Hot water production system

Abstract

To provide a warm water production system which can remedy drawbacks of an electric heat pump while optimally heating water according to whether an electric power demand adjustment is performed.SOLUTION: A warm water production system 1 for warming water to be used in a load facility 200 in a business establishment comprises: a first heating apparatus 10 for heating water by an electric heat pump 11; a second heating apparatus 20 for heating water by a combustion boiler 21; heating mode selection means 110 for selecting one of multiple heating modes according to whether an electric power demand adjustment is performed; and control means 120 for controlling operation of the first heating apparatus 10 and the second heating apparatus 20 according to the heating mode selected by the heating mode selection means 110.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hot water producing system. [Background technology]

[0002] Food and beverage manufacturing plants and manufacturing plants for automobiles, metal products, and machinery consume large amounts of hot water and heat in the production process. In recent years, many factories have been working on "decarbonization," moving away from fossil fuels, with the aim of reducing emissions of CO2, a greenhouse gas. As a result, as shown in Patent Document 1, electric heat pumps are increasingly being adopted as water heating devices in hot water production systems. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-229828 A Summary of the Invention [Problem to be solved by the invention]

[0004] Electric heat pumps are heat source devices that are extremely effective in reducing CO2 emissions, but they have the disadvantage that the equipment cost per heat output is about 10 times higher than that of combustion boilers. In addition, electric heat pumps have the disadvantage that they have a lower instantaneous power when outputting heat than combustion boilers, and that it takes a long time to obtain hot water at the desired temperature after starting up in cold mode. In order to promote the introduction of heat pumps, it is necessary to build a system that can compensate for these disadvantages. In recent years, Virtual Power Plant (VPP) systems have been attracting attention as a mechanism for adjusting the balance between power supply and demand. In a VPP system, it is expected that consumers will systematically adjust demand (demand response: DR) in response to the demands of the electricity market. Demand response includes "downward DR," which suppresses power consumption, and "upward DR," which promotes power consumption. In order to encourage consumers to participate in a VPP system while promoting the introduction of heat pumps, it is also necessary to build a system that can handle these DRs.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a hot water production system that can optimally heat water depending on whether or not power demand adjustment is implemented, while compensating for the shortcomings of electric heat pumps. [Means for solving the problem]

[0006] (1) The present invention is a hot water production system for warming water used in load equipment in a business establishment, comprising a first heating device for heating the water by an electric heat pump, a second heating device for heating the water by a combustion boiler, a heating mode selection means for selecting one of a plurality of heating modes including at least a first heating mode and a second heating mode depending on whether or not power demand adjustment is being implemented, and a control means for controlling the operation of the first heating device and the second heating device depending on the heating mode selected by the heating mode selection means, wherein the load equipment generates a demand for hot water by directly using the heated water, the heating mode selection means selects the first heating mode when power demand adjustment is not being implemented, and selects the second heating mode when power demand adjustment is being implemented to suppress power consumption more than when the first heating mode is selected, and the control means controls a hot water meter attached to the load equipment. and detecting a demand for hot water of the load equipment from a water level of a tank or a flow rate of makeup water, and operating the first heating device and the second heating device according to the detected demand for hot water. In the first heating mode, the first heating device is operated as a base load device and the second heating device is operated as a peak load device, and switching is performed between an independent operation of the first heating device and a coordinated operation of the first heating device and the second heating device, thereby allowing the hot water supply to follow changes in the demand for hot water of the load equipment. In the second heating mode, the second heating device is operated as a base load device and a peak load device, and the second heating device is operated as a base load device and a peak load device, and the hot water supply is allowed to follow changes in the demand for hot water of the load equipment by controlling the combustion boiler so that the thermal output of the second heating device in the second heating mode is greater than the thermal output of the second heating device in the first heating mode.

[0007] (2) The present invention also provides a hot water production system for warming water used in load equipment in a business establishment, the system comprising: a first heating device for heating the water by an electric heat pump; a second heating device for heating the water by a combustion boiler; a heating mode selection means for selecting one of a plurality of heating modes including at least a first heating mode and a second heating mode depending on whether or not power demand adjustment is being performed; and a control means for controlling operation of the first heating device and the second heating device depending on the heating mode selected by the heating mode selection means, the load equipment generating a demand for hot water by directly using the heated water, the heating mode selection means selecting the first heating mode when power demand adjustment is not being performed, and selecting the second heating mode when power demand adjustment is being performed to suppress power consumption more than when the first heating mode is selected, the control means detecting the hot water demand of the load equipment by the water level of a hot water tank attached to the load equipment or the flow rate of makeup water, and controlling the operation of the detected hot water The hot water producing system operates the first heating device and the second heating device in response to demand, and in the first heating mode, the first heating device is a base load device and the second heating device is a peak load device, and switching is performed between an independent operation of the first heating device and a coordinated operation of the first heating device and the second heating device, thereby allowing the hot water supply to follow changes in the hot water demand of the load equipment. In the second heating mode, the second heating device is a base load device and the first heating device is a peak load device, and switching is performed between an independent operation of the second heating device and a coordinated operation of the second heating device and the first heating device, and in the coordinated operation of the second heating device and the first heating device, the electric heat pump and the combustion boiler are controlled so that, in the coordinated operation of the second heating mode, the output ratio of the second heating device to the total thermal output of the first heating device and the second heating device is greater than the output ratio of the second heating device in the coordinated operation of the first heating mode, thereby allowing the hot water supply to follow changes in the hot water demand of the load equipment.

[0008] (3) The present invention also provides a hot water production system for warming water used in load equipment within a business establishment, the system comprising: a first heating device for heating the water by an electric heat pump; a second heating device for heating the water by a combustion boiler; a heating mode selection means for selecting one of a plurality of heating modes including at least a first heating mode and a second heating mode depending on whether or not power demand adjustment is performed; and a control means for controlling operation of the first heating device and the second heating device depending on the heating mode selected by the heating mode selection means, the load equipment generating a demand for hot water by indirectly using the heated water, the heating mode selection means selecting the first heating mode when power demand adjustment is not performed and selecting the second heating mode when power demand adjustment is performed to suppress power consumption more than when the first heating mode is selected, and the control means controlling a return temperature of hot water in a hot water loop system formed for the load equipment. the first heating device and the second heating device are operated in accordance with the detected demand for hot water; in the first heating mode, the first heating device is operated as a base load device and the second heating device is operated as a peak load device, and switching is performed between operating the first heating device alone and operating the first heating device and the second heating device in a coordinated manner, thereby allowing the supply of hot water to follow changes in the demand for hot water of the load equipment; and in the second heating mode, the second heating device is operated as a base load device and a peak load device, and the second heating device is operated alone, while the combustion boiler is controlled so that the thermal output of the second heating device in the second heating mode is greater than the thermal output of the second heating device in the first heating mode, thereby allowing the supply of hot water to follow changes in the demand for hot water of the load equipment.

[0009] (4) The present invention also provides a hot water production system for heating water used in load equipment in a business establishment, the system comprising: a first heating device for heating the water by an electric heat pump; a second heating device for heating the water by a combustion boiler; a heating mode selection means for selecting one of a plurality of heating modes including at least a first heating mode and a second heating mode depending on whether or not power demand adjustment is performed; and a control means for controlling operation of the first heating device and the second heating device depending on the heating mode selected by the heating mode selection means, the load equipment generating a demand for hot water by indirectly using the heated water, the heating mode selection means selecting the first heating mode when power demand adjustment is not performed, and selecting the second heating mode when power demand adjustment is performed to suppress power consumption more than when the first heating mode is selected, and the control means controlling the hot water demand of the load equipment by a return temperature of the hot water in a hot water loop system formed for the load equipment, or a difference between the supply temperature and the return temperature of the hot water in the hot water loop system. and operates the first heating device and the second heating device in response to the detected demand for hot water, and in the first heating mode, switches between an independent operation of the first heating device and a cooperative operation of the first heating device and the second heating device, with the first heating device as a base load device and the second heating device as a peak load device, thereby allowing the supply of hot water to follow changes in the demand for hot water of the load equipment; and in the second heating mode, switches between an independent operation of the second heating device and a cooperative operation of the second heating device and the first heating device, with the second heating device as a base load device and the first heating device as a peak load device, while controlling the electric heat pump and the combustion boiler so that, in the cooperative operation of the second heating mode, the output ratio of the second heating device to the total heat output of the first heating device and the second heating device is greater than the output ratio of the second heating device in the cooperative operation of the first heating mode, thereby allowing the supply of hot water to follow changes in the demand for hot water of the load equipment.

[0010] (5) Furthermore, in any of the hot water producing systems (1) to (4) above, the control means may detect the thermal output of the first heating device based on the outlet hot water temperature during operation of the first heating device, and in the first heating mode, switch between independent operation of the first heating device and coordinated operation of the first heating device and the second heating device depending on the thermal output of the first heating device.

[0011] (6) In addition, in any of the hot water production systems (1) to (4) above, a steam boiler may be used as the combustion boiler constituting the second heating device, and the water may be heated by direct or indirect heat exchange between the steam and the water.

[0012] (7) In the hot water producing system according to any one of the above (1) to (4), the combustion boiler may use a fuel selected from the group consisting of hydrogen, ammonia, biomethane, and bioethanol. Effect of the Invention

[0013] According to the present invention, it is possible to provide a hot water producing system that can perform optimal water heating depending on whether or not power demand adjustment is being implemented while compensating for the shortcomings of an electric heat pump. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram showing a schematic configuration of a hot water producing system according to a first embodiment of the present invention; [Diagram 2] FIG. 4 is a diagram showing a schematic configuration of a hot water producing system according to a second embodiment of the present invention. [Diagram 3] FIG. 10 is a diagram showing a schematic configuration of a hot water producing system according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a diagram showing a schematic configuration of a hot water producing system according to a fourth embodiment of the present invention. [Diagram 5] FIG. 13 is a diagram showing a schematic configuration of a hot water producing system according to a fifth embodiment of the present invention. [Figure 6]FIG. 13 is a diagram showing a schematic configuration of a hot water producing system according to a sixth embodiment of the present invention. [Figure 7] FIG. 13 is a diagram showing a schematic configuration of a hot water producing system according to a seventh embodiment of the present invention. [Figure 8] FIG. 13 is a diagram showing a schematic configuration of a hot water producing system according to an eighth embodiment of the present invention. [Figure 9] FIG. 13 is a diagram showing a schematic configuration of a hot water producing system according to a ninth embodiment of the present invention. [Figure 10] FIG. 23 is a diagram showing a schematic configuration of a hot water producing system according to a tenth embodiment of the present invention. [Figure 11] FIG. 23 is a diagram showing a schematic configuration of a hot water producing system according to an eleventh embodiment of the present invention. [Figure 12] FIG. 23 is a diagram showing a schematic configuration of a hot water producing system according to a twelfth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (First embodiment) Hereinafter, a first embodiment of a hot water producing system 1 of the present invention will be described with reference to the drawings. Note that in this specification, the term "line" is a general term for a line, such as a flow path, a pathway, or a pipe, through which a fluid can flow.

[0016] Fig. 1 is a diagram showing a schematic configuration of a hot water producing system 1 according to a first embodiment. The hot water producing system 1 includes a first heating device 10 that heats the water W1 with an electric heat pump 11, a second heating device 20 that heats the water W1 with a combustion boiler 21, and a control unit 100. The hot water producing system 1 of this embodiment further includes a hot water tank 30, a water distribution line L10, and a water return line L20. The hot water producing system 1 heats the water W1 to be used in a load facility 200 within a business establishment.

[0017] Here, the business establishment refers to an individual location where the production of goods or the provision of services is carried out as a business, such as a factory, a commercial facility, a medical institution, a welfare facility, an accommodation facility, or a research facility. The service water W1 refers to water used in the production of goods or the provision of services. When the business establishment is a factory, the load equipment 200 refers to production equipment (equipment directly involved in the production of goods), such as a food or beverage manufacturing factory, or a manufacturing factory for automobiles, metal products, or machinery and equipment. The heated service water W1 is used directly as cleaning water, etc., and is also used indirectly as heat transfer water. An example of the load equipment 200 other than the production equipment of a factory is a steam boiler device (heat source equipment involved in the operation of the production equipment), and a part of the heated service water W1 is used as boiler feed water. The load equipment 200 in this embodiment indirectly uses the heated service water W1 as heat transfer water (that is, outputs hot heat).

[0018] <Hot water tank> The hot water tank 30 stores the hot water, which is water W1, as stored water. In this embodiment, the hot water tank 30 is an open tank. The hot water tank 30 is equipped with a water level sensor 31. When the water level sensor 31 detects a decrease in the water level in the hot water tank 30 due to natural evaporation, makeup water W0 is supplied into the hot water tank 30 through the makeup water line L00. A temperature sensor (not shown) is provided in the hot water tank 30, and the temperature of the stored water in the hot water tank 30 is detected as the heat storage temperature TC of the hot water tank 30.

[0019] <Various lines> In this embodiment, a water distribution line L10, which is a hot water supply pipe from the hot water tank 30 to the load equipment 200, is laid, and a hot water return line L20, which is a hot water return pipe, is laid from the load equipment 200 to the hot water tank 30. This forms a circulation line of a hot water loop system.

[0020] The water distribution line L10 is a line for supplying the service water W1, which is hot water in the hot water tank 30, to the load equipment 200. A supply pump 50 is provided on the water distribution line L10.

[0021] The water return line L20 is a line for returning the water W1 from the load equipment 200 to the hot water tank 30. The water return line L20 branches from a branch point P into a first heating target line L21 and a second heating target line L22.

[0022] A first sub-heat exchanger 12 of a first heating device 10, which will be described later, is disposed in the first heating target line L21. The water W1 flowing through the first heating target line L21 is heated by the first sub-heat exchanger 12. A water passage valve 51 is provided in the first heating target line L21.

[0023] A second sub-heat exchanger 22 of a second heating device 20, which will be described later, is disposed in the second heating target line L22. The water W1 flowing through the second heating target line L22 is heated by the second sub-heat exchanger 22. A water passage valve 52 is provided in the second heating target line L22.

[0024] A temperature sensor 40 is provided on the water return line L20 upstream of a branch point P. The temperature sensor 40 detects a return temperature Tr of the hot water flowing through the water return line L20 upstream of the branch point P of the water return line.

[0025] <1st heating device> The first heating device 10 includes an electric heat pump 11 (abbreviated as HP), a first sub-heat exchanger 12, a first sub-circulation pump 13, and a first sub-circulation line LS1.

[0026] The first sub-circulation line LS1 connects the first sub-heat exchanger 12 and the condenser of the heat pump 11. The heat medium R1 circulating through the first sub-circulation line LS1 may be water. In particular, in hot water supply applications, the heat medium R1 is preferably water from the viewpoint of preventing the refrigerant from being mixed into the water W1 when the condenser breaks down.

[0027] The heat pump 11 heats the heat medium R1 circulating through the first sub-circulation line LS1. The heat pump 11 may be either an air heat source type or a water heat source type (groundwater, waste hot water, etc.). It may also be a heat pump chiller capable of simultaneously extracting hot and cold water.

[0028] The first sub-heat exchanger 12 exchanges heat between the water W1 flowing through the first heating target line L21 and the heat medium R1 flowing through the first sub-circulation line LS1 to heat the water W1. The first sub-heat exchanger 12 is disposed in the first heating target line L21 (including the return water line from the load equipment, the circulation line with the hot water tank, and the supply water line from the water supply equipment in each embodiment). A temperature sensor (not shown) is provided downstream of the first sub-heat exchanger 12 in the first heating target line L21, and the temperature of the hot water flowing through the first heating target line L21 after passing through the first sub-heat exchanger 12 is detected as the outlet temperature TA of the first sub-heat exchanger 12. In addition, a temperature sensor (not shown) is provided upstream of the first sub-heat exchanger 12 in the first heating target line L21, and the temperature of the hot water flowing through the first heating target line L21 before passing through the first sub-heat exchanger 12 is detected as the inlet temperature TA0 of the first sub-heat exchanger 12. The inlet / outlet temperature difference of the first sub-heat exchanger 12 is detected from the difference between the inlet temperature TA0 and the outlet temperature TA.

[0029] The first sub-circulation pump 13 is provided in the first sub-circulation line LS1. The first sub-circulation pump 13 circulates the heat medium R1 flowing through the first sub-circulation line LS1.

[0030] The first heating device 10 may be configured such that the first heating target line L21 is directly connected to the condenser of the heat pump 11. In this case, the first sub-heat exchanger 12 and the first sub-circulation line LS1 can be omitted.

[0031] <Second heating device> The second heating device 20 has a combustion boiler 21, a second sub-heat exchanger 22, a second sub-circulation pump 23, and a second sub-circulation line LS2.

[0032] The second sub-circulation line LS2 connects the second sub-heat exchanger 22 and the hot water boiler main body of the combustion boiler 21. The heat medium R2 circulating through the second sub-circulation line LS2 may be water.

[0033] The combustion boiler 21 heats the heat medium R2 circulating through the second sub-circulation line LS2. The combustion boiler 21 may be a boiler that uses a fuel selected from hydrocarbons, hydrogen, and ammonia. The combustion boiler 21 may be either a hot water boiler (abbreviation: BH) or a steam boiler (abbreviation: BS). In this embodiment, the hot water boiler 21 is used as the combustion boiler. The hot water boiler 21 includes a vacuum type hot water heater and a non-pressure type hot water heater.

[0034] The second sub-heat exchanger 22 exchanges heat between the water W1 flowing through the second heating target line L22 and the heat medium R2 flowing through the second sub-circulation line LS2 to heat the water W1. The second sub-heat exchanger 22 is disposed in the second heating target line L22 (including the return water line from the load equipment, the circulation line with the hot water tank, and the supply water line from the water supply equipment in each embodiment). A temperature sensor (not shown) is provided downstream of the second sub-heat exchanger 22 in the second heating target line L22, and the temperature of the hot water flowing through the second heating target line L22 after passing through the second sub-heat exchanger 22 is detected as the outlet temperature TB of the second sub-heat exchanger 22. In addition, a temperature sensor (not shown) is provided upstream of the second sub-heat exchanger 22 in the second heating target line L22, and the temperature of the hot water flowing through the second heating target line L22 before passing through the second sub-heat exchanger 22 is detected as the inlet temperature TB0 of the second sub-heat exchanger 22. The inlet / outlet temperature difference of the second sub-heat exchanger 22 is detected from the difference between the inlet temperature TB0 and the outlet temperature TB.

[0035] The second sub-circulation pump 23 is provided in the second sub-circulation line LS2. The second sub-circulation pump 23 circulates the heat medium R2 flowing through the second sub-circulation line LS2.

[0036] The second heating device 20 may be a device that heats the water W1 by exchanging heat between the steam generated in the combustion boiler 21 and the water W1. For example, the second heating device 20 may be configured such that a second sub-heat exchanger 22 is disposed in the second heating target line L22 (including the return water line from the load equipment, the circulation line with the hot water tank, and the supply water line from the water supply equipment in each embodiment), and a steam line extending from the steam boiler via a steam header is connected to the second sub-heat exchanger 22. A steam supply valve (proportional control valve) is provided in the steam line.

[0037] In this way, the combustion boiler 21 constituting the second heating device 20 can be not only a hot water boiler but also a steam boiler. When a steam boiler is used as a heat source, the steam and the water are indirectly or directly heat exchanged to heat the water. For example, when using steam with an absolute pressure of 0.3 MPa to 2 MPa generated by a small once-through steam boiler, the saturation temperature reaches 150 to 215°C, so that the heating operation time can be shortened even when producing hot water at 80 to 90°C. As a result, the increase in CO2 emissions is suppressed.

[0038] The hot water production system 1 may further include a third heating device that heats the boiler feed water with a heat recovery electric heat pump. A third heating device incorporating a heat recovery electric heat pump that uses waste hot water or the like as a heat source is installed to heat the boiler feed water for the steam boiler. This makes it possible to significantly reduce CO2 emissions from the combustion boiler when using steam energy in the third heating mode.

[0039] As shown in other embodiments described later, the second heating device 20 may be a device that heats the water stored in the hot water tank 30. In this case, the heating means of the second heating device 20 may be any one of (A) a steam blowing pipe (direct heating) installed inside the hot water tank 30, (B) a steam heater 25 (indirect heating) installed inside the hot water tank 30, and (C) a steam heat exchanger (indirect heating by water circulation) installed outside the hot water tank 30.

[0040] As described above, the hot water producing system 1 of this embodiment has the water return line L20 as a heating target line that supplies water to the hot water tank 30, and the first heating device 10 and the second heating device 20 heat the water W1 flowing through the heating target line. In addition, the heating target line is branched, and the first heating device 10 and the second heating device 20 are arranged in parallel.

[0041] <Control Unit> The control unit 100 includes a heating mode selection unit 110 as a heating mode selection means, an operation control unit 120 as a control means, and a storage unit 130.

[0042] The control unit 100 may be a server. The control unit 100 is configured with a plurality of functional blocks as described above, but the functional blocks do not necessarily need to be physically separated, and one CPU may realize the functions of a plurality of functional blocks. The control unit 100 may be arranged in two or more locations, taking into consideration the arrangement of the parts to be controlled, etc. One functional block may be divided into two or more locations and controlled in a distributed manner. The storage unit is configured with a recording medium such as a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a removable memory card. Examples of the recording medium include non-transitory tangible media. The control unit 100 is configured to include an arithmetic processor such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and an FPGA (Field-Programmable Gate Array). Various functions of the control unit 100 are realized, for example, by executing a program (application) stored in the storage unit. The program (application) may be provided via a network, or may be provided by being recorded on a computer-readable storage medium such as a CD-ROM (Compact Disc Read only memory) or a DVD (Digital Versatile Disc). Each function of the control unit 100 may be realized by a combination of hardware and software, or may be realized only by hardware (electronic circuitry).

[0043] The heating mode selection unit 110 selects one heating mode from among a plurality of heating modes depending on whether or not power demand adjustment is performed. The plurality of heating modes include a first heating mode, a second heating mode, and a third heating mode. The heating mode selection unit 110 selects the first heating mode when power demand adjustment is not performed, selects the second heating mode when power demand adjustment is performed to suppress power consumption, and selects the third heating mode when power demand adjustment is performed to promote power consumption. The heating mode selection unit 110 selects one mode from among a plurality of heating modes based on input information from outside. The input information from outside is, for example, information on the activation of up-down DR provided by a resource aggregator (a business operator that directly concludes a VPP service contract with a consumer and controls resources) or the like.

[0044] The second heating mode may have a plurality of types of heating modes, such as the second heating mode A and the second heating mode B. The hot water production system 1 may be configured to execute only the second heating mode A as the second heating mode, or may be configured to execute only the second heating mode B, or may be configured to selectively execute either one of them. The third heating mode may have a plurality of types of heating modes, such as the third heating mode A and the third heating mode B. The hot water production system 1 may be configured to execute only the third heating mode A as the third heating mode, or may be configured to execute only the third heating mode B, or may be configured to selectively execute either one of them.

[0045] In addition, in the case where the system is configured to selectively execute either the second heating mode A or the second heating mode B, when the second heating mode is executed, the second heating mode A and the second heating mode B may be switched as needed depending on the operating hours of the business establishment and the required amount of power adjustment. Furthermore, the system may be shifted to the second heating mode B during execution of the second heating mode A. The same applies to the case where the system is configured to selectively execute either the third heating mode A or the third heating mode B.

[0046] The operation control unit 120 controls the operation of the first heating device 10 and the second heating device 20 according to the heating mode selected by the heating mode selection unit 110. In controlling the operation of the first heating device 10 and the second heating device 20, the operation control unit 120 controls various devices constituting the hot water producing system 1, such as the refrigerant compressor of the heat pump 11, the water valve 51 of the first sub-heat exchanger 12, the burner of the hot water boiler 21, the water valve 52 of the second sub-heat exchanger 22, the first sub-circulation pump 13, and the second sub-circulation pump 23.

[0047] The operation control unit 120 acquires information on the return temperature Tr detected by the temperature sensor 40, the outlet temperature TA of the first sub-heat exchanger 12, and the outlet temperature TB of the second sub-heat exchanger 22, for example, and controls the operation of the first heating device 10 and the second heating device 20 based on this information. The operation control unit 120 may compare the return temperature Tr detected by the temperature sensor 40 with a plurality of set temperatures and control the operation of the first heating device 10 and the second heating device 20. The operation control unit 120 may compare the return temperature Tr detected by the temperature sensor 40 with three set temperatures T1>T2>T3, for example, and control the operation of the first heating device 10 and the second heating device 20. Each set temperature may be set based on input information from the outside. Each set temperature may be stored in the memory unit 130 of the control unit 100.

[0048] <<Control of the first heating mode>> As described above, the first heating mode is selected by the heating mode selection unit 110 when power demand adjustment is not performed. In the first heating mode, the operation control unit 120 switches between the independent operation of the first heating device 10 and the cooperative operation of the first heating device 10 and the second heating device 20 according to the hot water demand in the load equipment 200, the heat demand in the load equipment 200, or the heat output of the first heating device 10. In this embodiment, the operation control unit 120 controls the operation of the first heating device 10 and the second heating device 20 according to the heat demand in the load equipment 200. For example, an index indicating the heat demand of the load equipment 200 is the return temperature Tr of the hot water from the load equipment 200 side in the hot water loop system. The lower the return temperature Tr, the greater the heat demand.

[0049] Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0050] [1] For example, the set temperatures are T1 = 70°C (return temperature at zero load, i.e., equivalent to the target hot water temperature), T2 = 60°C (equivalent to return temperature at average base load), and T3 = 50°C (equivalent to return temperature at average peak load). However, the numerical examples of each set temperature do not take into account heat loss associated with hot water circulation.

[0051] [2] The water valve 51 of the first sub-heat exchanger 12 is always open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 52 of the second sub-heat exchanger 22 is opened when the second heating device 20 starts operating and closed when the operation ends.

[0052] [3] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0053] [4] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0054] [5] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, and the second sub-circulation pump 23 is stopped.

[0055] [6] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the second heating device 20 starts operating. Specifically, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to the first target temperature (e.g., 70°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (e.g., 70°C).

[0056] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment is performed to suppress power consumption. In the second heating mode A, the operation control unit 120 executes an independent operation of the second heating device 20 in response to the hot water demand in the load equipment 200 or the heat demand in the load equipment 200. In this embodiment, the operation control unit 120 executes an independent operation of the second heating device 20 in response to the heat demand in the load equipment 200.

[0057] An example of control by the operation control unit 120 in the second heating mode A will be described below.

[0058] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. To this end, the set temperature T1 is changed from 70°C to 90°C, and the set temperature T2 is changed from 60°C to 70°C. In this heating mode, there is no cooperative operation with the first heating device 10.

[0059] [2] The water valve 52 of the second sub-heat exchanger 22 is always kept open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 51 of the first sub-heat exchanger 12 is closed.

[0060] [3] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90° C.), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, and the second sub-circulation pump 23 is stopped.

[0061] [4] When the return temperature Tr becomes lower than the set temperature T2 (Tr<70° C.), the second heating device 20 starts operating. Specifically, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes fuel consumption of the second heating device 20 is continued while also satisfying the peak demand of the load equipment 200.

[0062] In this way, it is preferable that the operation control unit 120 controls the combustion boiler 21 so that the heat output of the second heating device 20 in the second heating mode is greater than the heat output of the second heating device 20 in the first heating mode.

[0063] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when implementing power demand adjustment to promote power consumption. In the third heating mode A, the operation control unit 120 executes independent operation of the first heating device 10 in response to the heat demand in the load equipment 200 or in response to the heat demand in the load equipment 200. In this embodiment, the operation control unit 120 executes independent operation of the first heating device 10 in response to the heat demand in the load equipment 200.

[0064] An example of control by the operation control unit 120 in the third heating mode A will be described below.

[0065] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. To this end, the set temperature T1 is changed from 70°C to 90°C, and the set temperature T2 is changed from 60°C to 70°C. In this heating mode, there is no cooperative operation with the second heating device 20.

[0066] [2] The water valve 51 of the first sub-heat exchanger 12 is always kept open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 52 of the second sub-heat exchanger 22 is closed.

[0067] [3] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0068] [4] When the return temperature Tr becomes lower than the set temperature T2 (Tr<70° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes the power consumption of the first heating device 10 is continued while also satisfying the peak demand of the load equipment 200.

[0069] In this way, it is preferable that the operation control unit 120 controls the electric heat pump 11 so that the heat output of the first heating device 10 in the third heating mode is greater than the heat output of the first heating device 10 in the first heating mode.

[0070] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when implementing power demand adjustment to suppress power consumption. In the second heating mode B, the operation control unit 120 switches between the independent operation of the second heating device 20 and the cooperative operation of the second heating device 20 and the first heating device 10 according to the hot water demand in the load equipment 200 or the heat demand in the load equipment 200, and controls the electric heat pump 11 and the combustion boiler 21 in the cooperative operation of the second heating mode B so that the output ratio of the second heating device 20 to the total heat output of the first heating device 10 and the second heating device 20 is greater than the output ratio of the second heating device 20 in the cooperative operation of the first heating mode. In this embodiment, the operation control unit 120 executes such control according to the heat demand in the load equipment 200.

[0071] An example of control by the operation control unit 120 in the second heating mode B will be described below.

[0072] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0073] [2] The water valve 52 of the second sub-heat exchanger 22 is always kept open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 51 of the first sub-heat exchanger 12 is opened when the first heating device 10 starts operating and closed when the operation ends.

[0074] [3] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, and the second sub-circulation pump 23 is stopped.

[0075] [4] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the second heating device 20 starts operating. Specifically, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (for example, 70° C.).

[0076] [5] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0077] [6] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the second heating device 20 (i.e., raising the output ratio) and lowering the outlet temperature of the first heating device 10 (i.e., lowering the output ratio) more than in the first heating mode, it is possible to suppress the power consumption of the first heating device 10 while performing the cooperative operation.

[0078] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when implementing power demand adjustment to promote power consumption. In the third heating mode B, the operation control unit 120 switches between the independent operation of the first heating device 10 and the cooperative operation of the first heating device 10 and the second heating device 20 according to the hot water demand in the load equipment 200 or the heat demand in the load equipment 200, and controls the electric heat pump 11 and the combustion boiler 21 in the cooperative operation of the third heating mode B so that the output ratio of the first heating device 10 to the total heat output of the first heating device 10 and the second heating device 20 is greater than the output ratio of the first heating device 10 in the cooperative operation of the first heating mode. In this embodiment, the operation control unit 120 executes such control according to the heat demand in the load equipment 200.

[0079] Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0080] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0081] [2] The water valve 52 of the first sub-heat exchanger 12 is always open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 52 of the second sub-heat exchanger 22 is opened when the second heating device 20 starts operating and closed when the operation ends.

[0082] [3] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0083] [4] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0084] [5] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, and the second sub-circulation pump 23 is stopped.

[0085] [6] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the second heating device 20 starts operating. Specifically, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the first heating device 10 (i.e., increasing the output ratio) and lowering the outlet temperature of the second heating device 20 (i.e., decreasing the output ratio) more than in the first heating mode, it is possible to promote power consumption of the first heating device 10 while performing the cooperative operation.

[0086] <Indicators of hot water demand, heat demand and heat output> In the above-described control example, the operation control unit 120 controls the operation of the first heating device 10 and the second heating device 20 in accordance with the return temperature Tr as the heat demand of the load equipment 200. However, the operation control unit 120 can control the operation of the first heating device 10 and the second heating device 20 in accordance with the hot water demand of the load equipment 200, the hot heat demand of the load equipment 200, or the heat output of the first heating device 10. Below, (1) an index indicating the hot water demand of the load equipment 200, (2) an index indicating the hot heat demand of the load equipment 200, and (3) an index indicating the heat output of the first heating device 10 will be described.

[0087] (1) Indicators of hot water demand of the load equipment 200 include the water level of the stored water (= amount of stored hot water and amount of remaining hot water) in a system with a hot water tank 30, and the make-up water flow rate (= hot water consumption flow rate) in a system without a hot water tank 30. The lower the amount of stored hot water or the higher the water supply flow rate, the greater the hot water demand (= the greater the amount of make-up water supplied per hour). When cooperative operation in the first heating mode is selected, if the hot water demand of the load equipment 200 increases, the amount of hot water supplied per hour to the load equipment 200 is increased by heating the amount of make-up water that cannot be heated by the first heating device 10 with the second heating device 20.

[0088] (2) An index showing the heat demand of the load equipment 200 is the return temperature Tr of the hot water from the load equipment 200 side in the hot water loop system. The lower the return temperature Tr, the greater the heat demand. The index can also be the difference between the supply temperature and the return temperature. The greater the temperature difference, the greater the heat demand. When cooperative operation in the first heating mode is selected, if the heat demand of the load equipment 200 increases, and the outlet temperature of the first heating device 10 or the heat storage temperature TC of the hot water tank 30 does not meet the required temperature of the load equipment 200, the temperature is raised to the required temperature by heating with the second heating device 20.

[0089] (3) The outlet hot water temperature (service water outlet temperature) during operation is an index showing the thermal output of the first heating device 10. When the outlet hot water temperature of the first heating device 10 is low, the second heating device 20 is operated in coordination with the first heating device 10, and combustion energy is used to back up the heating. Here, cases where the outlet hot water temperature of the first heating device 10 is low refer to the following cases, for example. (a) When the target hot water outlet temperature cannot be obtained even if the output of the refrigerant compressor is increased due to a drop in the temperature of the heat source air of the heat pump 11 (low temperature outside air in winter, etc.) or a drop in the temperature of the heat source water (low temperature waste hot water, such as at the start of operation). (b) When the target hot water outlet temperature cannot be obtained even if the output of the refrigerant compressor is increased due to a decrease in the temperature of the supply water from the water supply equipment (low-temperature supply water, such as in winter) or a decrease in the temperature of the return hot water from the load equipment 200 (low-temperature circulating water, such as at the start of operation). (c) When a simultaneous hot and cold water extraction heat pump is used, the hot water temperature drops due to control to maintain the cold water temperature at the target temperature. (d) When the target temperature is lowered due to a decrease in the heating capacity of the heat pump 11 (mainly due to a decrease in the heat source temperature or the inlet temperature).

[0090] Second embodiment Next, a second embodiment will be described. Fig. 2 is a diagram showing a schematic configuration of a hot water production system 1 in this embodiment. In this embodiment, the same components as those in the first embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment indirectly uses the heated service water W1 as heat transfer water (that is, outputs hot heat).

[0091] 2, the hot water producing system 1 of this embodiment has a return water line L20 that is not branched and is connected to the hot water tank 30. The first heating device 10 and the second heating device 20 of the hot water producing system 1 of this embodiment are arranged in series in the return water line L20, which is the line to be heated, and heat the water W1 flowing through the return water line L20.

[0092] The first sub-heat exchanger 12 of the first heating device 10 is disposed in the water return line L20, which is the line to be heated. The first sub-heat exchanger 12 exchanges heat between the water W1 flowing through the water return line L20 and the heat medium R1 flowing through the first sub-circulation line LS1, and heats the water W1 flowing through the water return line L20.

[0093] The second sub-heat exchanger 22 of the second heating device 20 is disposed in the water return line L20 as the line to be heated. The second sub-heat exchanger 22 exchanges heat between the water W1 flowing through the water return line L20 and the heat medium R2 flowing through the second sub-circulation line LS2, and heats the water W1 flowing through the water return line L20.

[0094] A temperature sensor 40 that detects the return temperature Tr is provided on the water return line L20 upstream of the position where the first sub-heat exchanger 12 and the second sub-heat exchanger 22 are arranged.

[0095] As described above, in this embodiment, the first sub-heat exchanger 12 of the first heating device 10 and the second sub-heat exchanger 22 of the second heating device 20 are arranged in this order on the water return line L20 to heat the circulating water.

[0096] Hereinafter, an example of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0097] <<Control of the first heating mode>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0098] [1] For example, the set temperatures are T1 = 70°C (return temperature at zero load, i.e., equivalent to the target hot water temperature), T2 = 60°C (equivalent to return temperature at average base load), and T3 = 50°C (equivalent to return temperature at average peak load). However, the numerical examples of each set temperature do not take into account heat loss associated with hot water circulation.

[0099] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0100] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0101] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, and the second sub-circulation pump 23 is stopped.

[0102] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the second heating device 20 starts operating. Specifically, the second sub-circulation pump 23 is driven and the burner of the hot water boiler 21 is operated. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a first target temperature difference (e.g., 10°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a first target temperature (e.g., 70°C).

[0103] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0104] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. Therefore, only the set temperature T1 is changed from 70°C to 90°C. In this heating mode, there is no coordinated operation with the first heating device 10.

[0105] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90° C.), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, and the second sub-circulation pump 23 is stopped.

[0106] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the second heating device 20 starts operating. Specifically, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes fuel consumption of the second heating device 20 is continued while also satisfying the peak demand of the load equipment 200.

[0107] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0108] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. Therefore, only the set temperature T1 is changed from 70°C to 90°C. In this heating mode, the second heating device 20 is not operated in coordination with the third heating mode A.

[0109] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0110] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes the power consumption of the first heating device 10 is continued while also satisfying the peak demand of the load equipment 200.

[0111] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0112] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0113] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, and the second sub-circulation pump 23 is stopped.

[0114] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the second heating device 20 starts operating. Specifically, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (eg, 70° C.).

[0115] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0116] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a second target temperature difference (e.g., 5°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a first target temperature (e.g., 70°C). By lowering the inlet / outlet temperature difference of the first heating device 10 (i.e., lowering the output ratio) more than in the first heating mode, it is possible to suppress power consumption while performing coordinated operation with the second heating device 20.

[0117] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0118] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0119] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0120] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0121] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, and the second sub-circulation pump 23 is stopped.

[0122] [5] When the return temperature Tr becomes lower than the set temperature T3 (T5<50° C.), the second heating device 20 starts operating. Specifically, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature difference (e.g., 15°C). Also, during the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 70°C). By increasing the inlet / outlet temperature difference of the first heating device 10 more than in the first heating mode (i.e., increasing the output ratio), it is possible to promote power consumption while performing cooperative operation with the second heating device 20.

[0123] Third embodiment Next, a third embodiment will be described. Fig. 3 is a diagram showing a schematic configuration of a hot water production system 1 in this embodiment. In this embodiment, the same components as those in the first embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment indirectly uses the heated service water W1 as heat transfer water (that is, outputs hot heat).

[0124] As shown in Fig. 3, the first heating device 10 and the second heating device 20 are not arranged in the water return line L20 of the hot water producing system 1 of this embodiment. The water return line L20 is not branched, but is directly connected to the hot water tank 30. The hot water producing system 1 of this embodiment includes a circulation line L30 as a heating target line that circulates the stored water in the hot water tank 30. The first heating device 10 and the second heating device 20 heat the service water W1 as circulating water flowing through the circulation line L30.

[0125] The circulation line L30 is a line for circulating the service water W1, which is hot water, in the hot water tank 30. The circulation line L30 branches into a first circulation line L31 and a second circulation line L32 at a branch point P, and then merges.

[0126] The first circulation line L31 is provided with a first sub-heat exchanger 12 of the first heating device 10. A first circulation pump 53 is provided in the first circulation line L31.

[0127] The second circulation line L32 is provided with the second sub-heat exchanger 22 of the second heating device 20. The second circulation line L32 is provided with a second circulation pump .

[0128] The first sub-heat exchanger 12 exchanges heat between the water W1 circulating through the first circulation line L31 and the heat medium R1 circulating through the first sub-circulation line LS1, and heats the water W1 circulating through the first circulation line L31.

[0129] The second sub-heat exchanger 22 exchanges heat between the water W1 circulating through the second circulation line L32 and the heat medium R2 circulating through the second sub-circulation line LS2, and heats the water W1 circulating through the second circulation line L32.

[0130] The water return line L20 is provided with a temperature sensor 40 that detects the return temperature Tr.

[0131] As described above, in this embodiment, the first sub-heat exchanger 12 of the first heating device 10 and the first circulation pump 53 are arranged in the first circulation line L31 connected to the hot water tank 30 to heat the circulating water. Also, the second sub-heat exchanger 22 of the second heating device 20 and the second circulation pump 54 are arranged in the second circulation line L32 connected to the hot water tank 30 to heat the circulating water.

[0132] Hereinafter, an example of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0133] <<Control of the first heating mode>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0134] [1] For example, the set temperatures are T1 = 70°C (return temperature at zero load, i.e., equivalent to the target hot water temperature), T2 = 60°C (equivalent to return temperature at average base load), and T3 = 50°C (equivalent to return temperature at average peak load). However, the numerical examples of each set temperature do not take into account heat loss associated with hot water circulation.

[0135] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70°C), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first circulation pump is stopped.

[0136] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60°C), the operation of the first heating device 10 is started. Specifically, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0137] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60°C), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the second circulation pump is stopped.

[0138] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50°C), the second heating device 20 starts operating. Specifically, the second circulation pump is driven, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to the first target temperature (e.g., 70°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (e.g., 70°C).

[0139] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0140] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. To this end, the set temperature T1 is changed from 70°C to 90°C, and the set temperature T2 is changed from 60°C to 70°C. In this heating mode, there is no cooperative operation with the first heating device 10.

[0141] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr ≧ 90°C), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the second circulation pump is stopped.

[0142] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<70°C), the second heating device 20 starts operating. Specifically, the second circulation pump is driven, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes fuel consumption of the second heating device 20 is continued while also satisfying the peak demand of the load equipment 200.

[0143] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0144] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. To this end, the set temperature T1 is changed from 70°C to 90°C, and the set temperature T2 is changed from 60°C to 70°C. In this heating mode, there is no cooperative operation with the second heating device 20.

[0145] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90°C), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first circulation pump is stopped.

[0146] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<70°C), the operation of the first heating device 10 is started. Specifically, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes the power consumption of the first heating device 10 is continued while also satisfying the peak demand of the load equipment 200.

[0147] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0148] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0149] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70°C), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the second circulation pump is stopped.

[0150] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60°C), the second heating device 20 starts operating. Specifically, the second circulation pump is driven, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (eg, 70° C.).

[0151] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60°C), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first circulation pump is stopped.

[0152] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50°C), the operation of the first heating device 10 is started. Specifically, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the second heating device 20 (i.e., raising the output ratio) and lowering the outlet temperature of the first heating device 10 (i.e., lowering the output ratio) more than in the first heating mode, it is possible to suppress the power consumption of the first heating device 10 while performing the cooperative operation.

[0153] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0154] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0155] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70°C), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first circulation pump is stopped.

[0156] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60°C), the operation of the first heating device 10 is started. Specifically, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0157] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60°C), the operation of the second heating device 20 is terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the second circulation pump is stopped.

[0158] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50°C), the second heating device 20 starts operating. Specifically, the second circulation pump is driven, the second sub-circulation pump 23 is driven, and the burner of the hot water boiler 21 is operated. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the first heating device 10 (i.e., increasing the output ratio) and lowering the outlet temperature of the second heating device 20 (i.e., decreasing the output ratio) more than in the first heating mode, it is possible to promote power consumption of the first heating device 10 while performing the cooperative operation.

[0159] (Fourth embodiment) Next, a fourth embodiment will be described. Fig. 4 is a diagram showing a schematic configuration of a hot water production system 1 in this embodiment. In this embodiment, the same components as those in the first embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment indirectly uses the heated service water W1 as heat transfer water (that is, outputs hot heat).

[0160] As shown in Fig. 4, the water return line L20 of the hot water producing system 1 of this embodiment is not branched and is connected to the hot water tank 30. The first heating device 10 heats the water W1 flowing through the water return line L20 as the line to be heated. The second heating device 20 heats the water W1 as the stored water in the hot water tank 30.

[0161] The first sub-heat exchanger 12 of the first heating device 10 is disposed in the water return line L20, which is the line to be heated. The first sub-heat exchanger 12 exchanges heat between the water W1 flowing through the water return line L20 and the heat medium R1 flowing through the first sub-circulation line LS1, and heats the water W1 flowing through the water return line L20.

[0162] The second heating device 20 includes a steam boiler (not shown), a steam heater 25, a steam supply valve 26, and a steam line.

[0163] The steam line L40 supplies steam S from the steam boiler to the steam heater 25. The steam S after heat exchange in the steam heater 25 is discharged from the steam heater 25 through the steam line L40.

[0164] The steam heater 25 is installed inside the hot water tank 30. The steam heater 25 exchanges heat between the water W1 as stored water in the hot water tank 30 and the steam S flowing through the steam line L40, thereby heating the stored water.

[0165] The steam supply valve 26 controls the flow state of the steam S flowing through the steam line L40. The steam supply valve 26 is preferably a proportional control valve whose opening degree is adjustable.

[0166] A temperature sensor 40 that detects the return temperature Tr is provided upstream of the position where the first sub-heat exchanger 12 is disposed on the water return line L20.

[0167] As described above, in this embodiment, the first sub-heat exchanger 12 of the first heating device 10 is arranged in the water return line L20 to heat circulating water as the service water W1. The steam heater 25 of the second heating device 20 is arranged in the hot water tank 30 to heat stored water as the service water W1. Steam S generated in the steam boiler is supplied to the steam heater 25 (steam heat exchanger) via the steam supply valve 26.

[0168] Hereinafter, an example of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0169] <Control of 1 heating mode> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0170] [1] For example, the set temperatures are T1 = 70°C (return temperature at zero load, i.e., equivalent to the target hot water temperature), T2 = 60°C (equivalent to return temperature at average base load), and T3 = 50°C (equivalent to return temperature at average peak load). However, the numerical examples of each set temperature do not take into account heat loss associated with hot water circulation.

[0171] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0172] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0173] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0174] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a first target temperature difference (e.g., 10°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C).

[0175] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0176] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. Therefore, only the set temperature T1 is changed from 70°C to 90°C. In this heating mode, there is no coordinated operation with the first heating device 10.

[0177] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0178] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes fuel consumption of the second heating device 20 is continued while also satisfying the peak demand of the load equipment 200.

[0179] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0180] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. Therefore, only the set temperature T1 is changed from 70°C to 90°C. In this heating mode, the second heating device 20 is not operated in coordination with the third heating mode A.

[0181] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0182] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes the power consumption of the first heating device 10 is continued while also satisfying the peak demand of the load equipment 200.

[0183] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0184] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0185] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0186] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (eg, 70° C.).

[0187] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0188] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a second target temperature difference (e.g., 5°C). Also, during the coordinated operation of the second heating device 20, the opening degree of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C). By lowering the inlet / outlet temperature difference of the first heating device 10 compared to the first heating mode (i.e., lowering the output ratio), it is possible to suppress power consumption while performing coordinated operation with the second heating device 20.

[0189] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0190] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0191] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the first heating device 10 is stopped. Specifically, the refrigerant compressor of the heat pump 11 is stopped, and the first sub-circulation pump 13 is stopped.

[0192] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the operation of the first heating device 10 is started. Specifically, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0193] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0194] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature difference (e.g., 15°C). Also, during the cooperative operation of the second heating device 20, the opening degree of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 70°C). By increasing the inlet / outlet temperature difference of the first heating device 10 more than in the first heating mode (i.e., increasing the output ratio), it is possible to promote power consumption while performing cooperative operation with the second heating device 20.

[0195] Fifth embodiment Next, a fifth embodiment will be described. Fig. 5 is a diagram showing a schematic configuration of a hot water production system 1 in this embodiment. In this embodiment, the same components as those in the fourth embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment indirectly uses the heated service water W1 as heat transfer water (that is, outputs hot heat).

[0196] As shown in Fig. 5, the first heating device 10 is not disposed in the water return line L20 of the hot water producing system 1 of this embodiment. The hot water producing system 1 of this embodiment includes a first circulation line L31 as a heating target line that circulates the water stored in the hot water tank 30. The first heating device 10 heats the water W1 as circulating water flowing through the first circulation line L31. The second heating device 20 heats the water W1 as stored water in the hot water tank 30, similar to the fourth embodiment.

[0197] The first circulation line L31 is a line for circulating the hot water W1 in the hot water tank 30.

[0198] The first circulation line L31 is provided with a first sub-heat exchanger 12 of the first heating device 10. A first circulation pump 53 is provided in the first circulation line L31.

[0199] The first sub-heat exchanger 12 exchanges heat between the water W1 circulating through the first circulation line L31 and the heat medium R1 circulating through the first sub-circulation line LS1, and heats the water W1 circulating through the first circulation line L31.

[0200] The water return line L20 is provided with a temperature sensor 40 that detects the return temperature Tr.

[0201] As described above, in this embodiment, the first sub-heat exchanger 12 of the first heating device 10 and the first circulation pump 53 are arranged in the first circulation line L31 connected to the hot water tank 30 to heat the service water W1 as the circulating water. In addition, the steam heater 25 of the second heating device 20 is arranged in the hot water tank 30 to heat the stored water as the service water W1. Steam S generated in the steam boiler is supplied to the steam heater 25 (steam heat exchanger) via the steam supply valve 26.

[0202] Hereinafter, an example of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0203] <<Control of the first heating mode>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0204] [1] For example, the set temperatures are T1 = 70°C (return temperature at zero load, i.e., equivalent to the target hot water temperature), T2 = 60°C (equivalent to return temperature at average base load), and T3 = 50°C (equivalent to return temperature at average peak load). However, the numerical examples of each set temperature do not take into account heat loss associated with hot water circulation.

[0205] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70°C), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first circulation pump is stopped.

[0206] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60°C), the operation of the first heating device 10 is started. Specifically, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0207] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0208] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a first target temperature difference (e.g., 10°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C).

[0209] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0210] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. Therefore, only the set temperature T1 is changed from 70°C to 90°C. In this heating mode, there is no coordinated operation with the first heating device 10.

[0211] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0212] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes fuel consumption of the second heating device 20 is continued while also satisfying the peak demand of the load equipment 200.

[0213] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0214] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. Therefore, only the set temperature T1 is changed from 70°C to 90°C. In this heating mode, the second heating device 20 is not operated in coordination with the third heating mode A.

[0215] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90°C), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first circulation pump is stopped.

[0216] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60°C), the operation of the first heating device 10 is started. Specifically, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes the power consumption of the first heating device 10 is continued while also satisfying the peak demand of the load equipment 200.

[0217] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0218] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0219] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0220] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (eg, 70° C.).

[0221] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60°C), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first circulation pump is stopped.

[0222] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50°C), the operation of the first heating device 10 is started. Specifically, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During coordinated operation of the first heating device 10 and the second heating device 20, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a second target temperature difference (e.g., 5°C). Also, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to the first target temperature (e.g., 70°C). By lowering the inlet / outlet temperature difference of the first heating device 10 compared to the first heating mode (i.e., lowering the output ratio), it is possible to suppress power consumption while performing coordinated operation with the second heating device 20.

[0223] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0224] [1] The set temperatures T1 to T3 are the same as those in the first heating mode.

[0225] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70°C), the operation of the first heating device 10 is terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first circulation pump is stopped.

[0226] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60°C), the operation of the first heating device 10 is started. Specifically, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0227] [4] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0228] [5] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature difference (e.g., 15°C). Also, during the cooperative operation of the second heating device 20, the opening degree of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 70°C). By increasing the inlet / outlet temperature difference of the first heating device 10 more than in the first heating mode (i.e., increasing the output ratio), it is possible to promote power consumption while performing cooperative operation with the second heating device 20.

[0229] Sixth embodiment Next, a sixth embodiment will be described. Fig. 6 is a diagram showing a schematic configuration of a hot water production system 1 in this embodiment. In this embodiment, the same components as those in the fourth embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment indirectly uses the heated service water W1 as heat transfer water (that is, outputs hot heat).

[0230] As shown in Fig. 6, the water return line L20 of the hot water producing system 1 of this embodiment branches midway, and multiple first heating devices 10 are arranged in parallel. The multiple first heating devices 10 arranged in parallel heat the water W1 flowing through the water return line L20. In this embodiment, the first heating device group as the first heating device 10 is composed of a first unit 10A, a second unit 10B, and a third unit 10C. The second heating device 20 heats the water W1 as stored water in the hot water tank 30, as in the fourth embodiment.

[0231] The water return line L20 branches into a plurality of first heating target lines L21A, L21B, and L21C downstream of a branch point P. First heating devices 10A, 10B, and 10C are arranged in the plurality of first heating target lines L21A, 21B, and 21C, respectively.

[0232] Each of the first heating devices 10A, 10B, and 10C constituting the first heating device group has the same configuration as the first heating device 10 of the first embodiment. In Fig. 6, only the first sub-heat exchanger 12 of the first heating devices 10B and 10C is shown, and other configurations are omitted. Each of the first heating devices 10A, 10B, and 10C heats the water W1 flowing through the first heating target lines L21A, L21B, and L21C, respectively.

[0233] When controlling the number of units in the first heating device group (with an increase or decrease in the number of operating units), water valves 51A, 51B, and 51C are provided in the first heating target lines L21A, 21B, and 21C, respectively. When controlling the first heating device group collectively (without an increase or decrease in the number of operating units), the provision of water valves 51A, 51B, and 51C is not necessary.

[0234] As in the fourth embodiment, the second heating device 20 uses a steam heater 25 to heat the service water W1 as stored water in the hot water tank 30. Steam S from a steam boiler is supplied to the steam heater 25 through a steam line L40.

[0235] The combustion boiler constituting the second heating device 20 may be a hot water boiler instead of a steam boiler. When replaced with a hot water boiler, the second heating device 20 may be installed in the rear stage of the first heating device group, for example as shown in Fig. 2, and the heat output may be adjusted by the combustion amount of the burner.

[0236] A temperature sensor 40 is provided on the water return line L20 upstream of a branch point P. The temperature sensor 40 detects a return temperature Tr of the hot water flowing through the water return line L20 upstream of the branch point P of the water return line.

[0237] As described above, in this embodiment, the water return line L20 is branched midway, and the first sub-heat exchangers 12 of the multiple first heating devices 10A, 10B, and 10C are connected in parallel.

[0238] An example of control of each heating mode by the operation control unit 120 in this embodiment will be described below. The collective control of the first heating device group involves starting and stopping operation of all the devices at the same time, and the control of each heating mode conforms to the fourth embodiment. The control of the number of devices in the first heating device group follows the control explanation for each heating mode below. The control of the number of devices in the first heating device group is, for example, by comparing the return temperature Tr of the hot water flowing through the water return line L20 with five set temperatures T1>T2>T3>T4>T5, and increasing or decreasing the number of devices in operation.

[0239] <<Control of the first heating mode: Controlling the number of units in the first heating device group>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0240] [1] For example, the set temperatures are T1 = 70°C (return temperature at zero load, i.e., equivalent to the target hot water temperature), T2 = 66°C, T3 = 63°C, T4 = 60°C (respectively equivalent to return temperatures within the fluctuation range of the average base load), and T5 = 50°C (equivalent to return temperature at the average peak load). However, the numerical examples of each set temperature do not take into account heat loss associated with hot water circulation.

[0241] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70°C), the operation of the first heating device 10A (Unit 1) is terminated. When the return temperature Tr becomes equal to or lower than the set temperature T2 (Tr<66°C), the operation of the first heating device 10A (Unit 1) is started. When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧66°C), the operation of the first heating device 10B (Unit 2) is terminated. When the return temperature Tr becomes equal to or higher than the set temperature T3 (Tr<63°C), the operation of the first heating device 10B (Unit 2) is started. When the return temperature Tr becomes equal to or higher than the set temperature T3 (Tr≧63°C), the operation of the first heating device 10C (Unit 3) is terminated. When the return temperature Tr becomes equal to or lower than the set temperature T4 (Tr<60°C), the operation of the first heating device 10C (Unit 3) is started. During independent operation of the first heating device 10 (i.e., any one of units 1 to 3 is operating), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (e.g., 70°C).

[0242] [3] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0243] [4] When the return temperature Tr becomes lower than the set temperature T3 (Tr<50° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the coordinated operation of the first heating device 10 (i.e., all of the first to third units are in operation), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a first target temperature difference (e.g., 10°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C).

[0244] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0245] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. Therefore, only the set temperature T1 is changed from 70°C to 90°C. In this heating mode, there is no coordinated operation with the first heating device 10.

[0246] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧90° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0247] [3] When the return temperature Tr becomes lower than the set temperature T2 (Tr<60° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the independent operation that promotes fuel consumption of the second heating device 20 is continued while also satisfying the peak demand of the load equipment 200.

[0248] <<Control of the third heating mode A: Controlling the number of units in the first heating device group>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0249] [1] In the third heating mode A, in order to increase the target temperature of hot water supply and increase the amount of heat stored in the system, the set temperature T1 is changed from 70°C to 90°C, the set temperature T2 is changed from 66°C to 80°C, and the set temperature T3 is changed from 63°C to 70°C. In this heating mode, there is no coordinated operation with the second heating device 20.

[0250] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr ≧ 90°C), the operation of the first heating device 10A (Unit 1) is terminated. When the return temperature Tr becomes equal to or lower than the set temperature T2 (Tr < 80°C), the operation of the first heating device 10A (Unit 1) is started. When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr ≧ 80°C), the operation of the first heating device 10B (Unit 2) is terminated. When the return temperature Tr becomes equal to or higher than the set temperature T3 (Tr < 70°C), the operation of the first heating device 10B (Unit 2) is started. When the return temperature Tr becomes equal to or higher than the set temperature T3 (Tr ≧ 70°C), the operation of the first heating device 10C (Unit 3) is terminated. When the return temperature Tr becomes equal to or lower than the set temperature T4 (Tr < 60°C), the operation of the first heating device 10C (Unit 3) is started. During independent operation of the first heating device 10 (i.e., any one of the first to third units is in operation), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing the independent operation that promotes the power consumption of the first heating device 10.

[0251] <<Control of second heating mode B: Control of the number of units in the first heating device group>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0252] [1] The set temperatures T1 to T5 are the same as those in the first heating mode.

[0253] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0254] [3] When the return temperature Tr becomes less than the set temperature T2 (Tr<60°C), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to the first target temperature (e.g., 70°C).

[0255] [4] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70°C), the operation of the first heating device 10A (Unit 1) is terminated. When the return temperature Tr becomes equal to or lower than the set temperature T2 (Tr<66°C), the operation of the first heating device 10A (Unit 1) is started. When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧66°C), the operation of the first heating device 10B (Unit 2) is terminated. When the return temperature Tr becomes equal to or higher than the set temperature T3 (Tr<63°C), the operation of the first heating device 10B (Unit 2) is started. When the return temperature Tr becomes equal to or higher than the set temperature T3 (Tr≧63°C), the operation of the first heating device 10C (Unit 3) is terminated. When the return temperature Tr becomes equal to or lower than the set temperature T4 (Tr<60°C), the operation of the first heating device 10C (Unit 3) is started. During the coordinated operation of the first heating device 10 (i.e., all of the first to third units are in operation), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a second target temperature difference (e.g., 5°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C). By lowering the inlet / outlet temperature difference of the first heating device 10 compared to the first heating mode (i.e., lowering the output ratio), it is possible to suppress power consumption while performing coordinated operation with the second heating device 20.

[0256] <<Control of the third heating mode B: Controlling the number of units in the first heating device group>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0257] [1] The set temperatures T1 to T5 are the same as those in the first heating mode.

[0258] [2] When the return temperature Tr becomes equal to or higher than the set temperature T1 (Tr≧70°C), the operation of the first heating device 10A (Unit 1) is terminated. When the return temperature Tr becomes equal to or lower than the set temperature T2 (Tr<66°C), the operation of the first heating device 10A (Unit 1) is started. When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧66°C), the operation of the first heating device 10B (Unit 2) is terminated. When the return temperature Tr becomes equal to or higher than the set temperature T3 (Tr<63°C), the operation of the first heating device 10B (Unit 2) is started. When the return temperature Tr becomes equal to or higher than the set temperature T3 (Tr≧63°C), the operation of the first heating device 10C (Unit 3) is terminated. When the return temperature Tr becomes equal to or lower than the set temperature T4 (Tr<60°C), the operation of the first heating device 10C (Unit 3) is started. During independent operation of the first heating device 10 (i.e., any one of units 1 to 3 is operating), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (e.g., 70°C).

[0259] [3] When the return temperature Tr becomes equal to or higher than the set temperature T2 (Tr≧60° C.), the operation of the second heating device 20 is terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25.

[0260] [4] When the return temperature Tr becomes lower than the set temperature T3 (T5<50° C.), the second heating device 20 starts operating. Specifically, the steam supply valve 26 is opened to operate the steam heater 25. During the coordinated operation of the first heating device 10 (i.e., all of the first to third units are in operation), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature difference (e.g., 15°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 70°C). By increasing the inlet / outlet temperature difference of the first heating device 10 more than in the first heating mode (i.e., increasing the output ratio), it is possible to promote power consumption while performing coordinated operation with the second heating device 20.

[0261] Seventh embodiment Next, a seventh embodiment will be described. Fig. 7 is a diagram showing a schematic configuration of a hot water production system 1 in this embodiment. In this embodiment, the same components as those in the first embodiment are given the same reference numerals, and the description thereof may be omitted.

[0262] As shown in Fig. 7, the hot water producing system 1 of this embodiment has a water supply line L50 extending from a water supply facility. The first heating device 10 and the second heating device 20 heat the service water W1 as the supply water flowing through the water supply line L50. The hot water producing systems 1 of the above-described first to sixth embodiments mainly supply heat to the load equipment 200 by water circulation (i.e., hot heat output in the load equipment 200), but the hot water producing system 1 of this embodiment mainly supplies hot water to the load equipment 200 by passing through the water (i.e., hot water output in the load equipment 200).

[0263] The hot water tank 30 of this embodiment is an open tank. The hot water tank 30 includes a water level sensor 31. The water level sensor 31 detects the water level in the hot water tank 30 and compares it with, for example, three preset water levels L1>L2>L3. When the water level sensor 31 detects a reduction in water level due to hot water consumption, make-up water is supplied as service water W1 from the water supply facility through the water supply line L50.

[0264] A water distribution line L10, which is a hot water supply pipe, is laid from the hot water tank 30 to the load equipment 200 (single pipe hot water supply). Note that a water return line L20, which is a return pipe for excess hot water, may be laid from the load equipment 200 to the hot water tank 30 (circulating hot water supply).

[0265] The water supply line L50 is a line for supplying makeup water from a water supply facility as service water W1 to the hot water tank 30. The water supply line L50 branches from a branch point P into a first water supply line L51 and a second water supply line L52.

[0266] The first sub-heat exchanger 12 of the first heating device 10 is disposed in the first water supply line L51. In the case of circulating hot water supply, a water passage valve 51 is provided in the first water supply line L51.

[0267] The second sub-heat exchanger 22 of the second heating device 20 is disposed in the second water supply line L52. In the case of circulating hot water supply, a water passage valve 52 is provided in the second water supply line L52.

[0268] Two supply water pumps 55A, 55B are installed in parallel on the water supply line L50 upstream of the branch point P of the water supply line L50. The rotation speed (driving frequency) of each supply water pump 55A, 55B is constant, and the supply water flow rate is adjusted in two stages by switching between driving and stopping each supply water pump 55A, 55B according to the detected water level in the hot water tank 30. When only the first supply water pump 55A is driven, water is supplied at a first flow rate, and when both the first supply water pump 55A and the second supply water pump 55B are driven, water is supplied at a second flow rate (>first flow rate).

[0269] The first sub-heat exchanger 12 of the first heating device 10 is disposed in the first water supply line L51 as the line to be heated. The first sub-heat exchanger 12 exchanges heat between the water W1 flowing through the first water supply line L51 and the heat medium R1 flowing through the first sub-circulation line LS1, and heats the water W1 flowing through the first water supply line L51.

[0270] The second sub-heat exchanger 22 of the second heating device 20 is disposed in the second water supply line L52 as the line to be heated. The second sub-heat exchanger 22 exchanges heat between the water W1 flowing through the second water supply line L52 and the heat medium R2 flowing through the second sub-circulation line LS2, and heats the water W1 flowing through the second water supply line L52.

[0271] As described above, the hot water producing system 1 of this embodiment has the water supply line L50 as a heating target line that supplies water to the hot water tank 30, and the first heating device 10 and the second heating device 20 heat the water W1 flowing through the heating target line. In addition, the heating target line is branched, and the first heating device 10 and the second heating device 20 are arranged in parallel.

[0272] Hereinafter, an example of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0273] <<Control of the first heating mode>> As described above, the first heating mode is selected by the heating mode selection unit 110 when power demand adjustment is not performed. In this embodiment, in the first heating mode, the operation control unit 120 controls the operation of the first heating device 10 and the second heating device 20 in accordance with the hot water demand in the load equipment 200. An index indicating the hot water demand of the load equipment 200 is, for example, the water level of the stored water in the hot water tank 30 (=amount of stored hot water / amount of remaining hot water). A smaller amount of stored hot water indicates a greater demand for hot water (=a larger amount of makeup water supplied per hour).

[0274] Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0275] [1] In the case of circulating hot water supply, the water valve 51 of the first sub-heat exchanger 12 is always kept open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 52 of the second sub-heat exchanger 22 is opened when the second heating device 20 starts operating and closed when the operation ends.

[0276] [2] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first water supply pump 55A is stopped.

[0277] [3] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0278] [4] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0279] [5] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. The first feedwater pump 55A continues to be driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to the first target temperature (e.g., 70°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (e.g., 70°C).

[0280] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment is performed to suppress power consumption. In this embodiment, in the second heating mode A, the operation control unit 120 executes an independent operation of the second heating device 20 in response to the hot water demand in the load equipment 200.

[0281] An example of control by the operation control unit 120 in the second heating mode A will be described below.

[0282] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the first heating device 10 is performed.

[0283] [2] In the case of circulating hot water supply, the water valve 52 of the second sub-heat exchanger 22 is always kept open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 51 of the first sub-heat exchanger 12 is closed.

[0284] [3] When the detected water level reaches or exceeds the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the first feedwater pump 55A is stopped.

[0285] [4] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. During independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes fuel consumption of the second heating device 20. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be taken out.

[0286] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment is performed to promote power consumption. In this embodiment, in the third heating mode A, the operation control unit 120 executes independent operation of the first heating device in response to the hot water demand in the load equipment 200.

[0287] An example of control by the operation control unit 120 in the third heating mode A will be described below.

[0288] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the second heating device 20 is performed.

[0289] [2] In the case of circulating hot water supply, the water valve 51 of the first sub-heat exchanger 12 is always kept open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 52 of the second sub-heat exchanger 22 is closed.

[0290] [3] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first water supply pump 55A is stopped.

[0291] [4] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes power consumption of the first heating device 10. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be extracted.

[0292] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment is performed to suppress power consumption. In this embodiment, in the second heating mode B, the operation control unit 120 switches between the independent operation of the second heating device 20 and the cooperative operation of the second heating device 20 and the first heating device 10 according to the hot water demand in the load equipment 200, and controls the electric heat pump 11 and the combustion boiler 21 in the cooperative operation of the second heating mode B so that the output ratio of the second heating device 20 to the total heat output of the first heating device 10 and the second heating device 20 is greater than the output ratio of the second heating device 20 in the cooperative operation of the first heating mode.

[0293] Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0294] [1] The water valve 52 of the second sub-heat exchanger 22 is always kept open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 51 of the first sub-heat exchanger 12 is opened when the first heating device 10 starts operating and closed when the operation ends.

[0295] [2] When the detected water level reaches or exceeds the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the first feedwater pump 55A is stopped.

[0296] [3] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (for example, 70° C.).

[0297] [4] When the detected water level becomes equal to or higher than the set water level L2, the water supply at the second flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the second water supply pump 55B is stopped. The first water supply pump 55A continues to operate.

[0298] [5] When the detected water level falls below the set water level L3, water supply at the second flow rate and operation of the first heating device 10 are started. Specifically, the second water supply pump 55B is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. The first water supply pump 55A continues to be driven. During the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the second heating device 20 (i.e., raising the output ratio) and lowering the outlet temperature of the first heating device 10 (i.e., lowering the output ratio) more than in the first heating mode, it is possible to suppress the power consumption of the first heating device 10 while performing the cooperative operation.

[0299] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment is performed to promote power consumption. In this embodiment, in the third heating mode B, the operation control unit 120 switches between the independent operation of the first heating device 10 and the cooperative operation of the first heating device 10 and the second heating device 20 according to the hot water demand in the load equipment 200, and controls the electric heat pump 11 and the combustion boiler 21 in the cooperative operation of the third heating mode B so that the output ratio of the first heating device 10 to the total heat output of the first heating device 10 and the second heating device 20 is greater than the output ratio of the first heating device 10 in the cooperative operation of the first heating mode.

[0300] Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0301] [1] The water valve 51 of the first sub-heat exchanger 12 is always open to return hot water from the load equipment 200 to the hot water tank 30. The water valve 52 of the second sub-heat exchanger 22 is opened when the second heating device 20 starts operating and closed when the operation ends.

[0302] [2] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first water supply pump 55A is stopped.

[0303] [3] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0304] [4] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0305] [5] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. The first feedwater pump 55A continues to be driven. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the first heating device 10 (i.e., increasing the output ratio) and lowering the outlet temperature of the second heating device 20 (i.e., decreasing the output ratio) more than in the first heating mode, it is possible to promote power consumption of the first heating device 10 while performing the cooperative operation.

[0306] Eighth embodiment Next, an eighth embodiment will be described. Fig. 8 is a diagram showing a schematic configuration of a hot water production system 1 in this embodiment. In this embodiment, the same components as those in the seventh embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment directly uses the heated service water W1 as washing water or the like (that is, outputs heated water).

[0307] As shown in Fig. 8, the water supply line L50 of the hot water producing system 1 of this embodiment is not branched and is connected to the hot water tank 30. The first heating device 10 and the second heating device 20 of the hot water producing system 1 of this embodiment are arranged in series in the water supply line L50 as the line to be heated, and heat the water W1 flowing through the water supply line L50. Here, the configuration in which the first heating device 10 and the second heating device 20 are arranged in series in the line to be heated (water supply line L50) is the same as in the second embodiment, and therefore a description thereof will be omitted. In the case of circulating hot water supply, a water passage valve is provided in the branch line.

[0308] Hereinafter, examples of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0309] <<Control of the first heating mode>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0310] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first water supply pump 55A is stopped.

[0311] [2] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0312] [3] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0313] [4] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. The first feedwater pump 55A continues to be driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a first target temperature difference (e.g., 30°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a first target temperature (e.g., 70°C).

[0314] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0315] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the first heating device 10 is performed.

[0316] [2] When the detected water level reaches or exceeds the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the first feedwater pump 55A is stopped.

[0317] [3] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. During independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes fuel consumption of the second heating device 20. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be taken out.

[0318] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0319] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the second heating device 20 is performed.

[0320] [2] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first water supply pump 55A is stopped.

[0321] [3] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes power consumption of the first heating device 10. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be extracted.

[0322] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0323] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the first feedwater pump 55A is stopped.

[0324] [2] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (for example, 70° C.).

[0325] [3] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the second water supply pump 55B is stopped. The first water supply pump 55A continues to operate.

[0326] [4] When the detected water level falls below the set water level L3, water supply at the second flow rate and operation of the first heating device 10 are started. Specifically, the second water supply pump 55B is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. The first water supply pump 55A continues to be driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a second target temperature difference (e.g., 25°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a first target temperature (e.g., 70°C). By lowering the inlet / outlet temperature difference of the first heating device 10 (i.e., lowering the output ratio) more than in the first heating mode, it is possible to suppress power consumption while performing coordinated operation with the second heating device 20.

[0327] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0328] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the 21st water supply pump is stopped.

[0329] [2] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0330] [3] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0331] [4] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. The first feedwater pump 55A continues to be driven. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature difference (e.g., 35°C). Also, during the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 70°C). By increasing the inlet / outlet temperature difference of the first heating device 10 more than in the first heating mode (i.e., increasing the output ratio), it is possible to promote power consumption while performing cooperative operation with the second heating device 20.

[0332] Ninth embodiment Next, a ninth embodiment will be described. Fig. 9 is a diagram showing a schematic configuration of a hot water producing system 1 in this embodiment. In this embodiment, the same components as those in the seventh embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment directly uses the heated service water W1 as washing water or the like (that is, outputs heated water).

[0333] As shown in FIG. 9, the first heating device 10 and the second heating device 20 are not arranged in the water supply line L50 of the hot water producing system 1 of this embodiment. The water supply line L50 is not branched and is directly connected to the hot water tank 30. The hot water producing system 1 of this embodiment includes a circulation line L30 as a heating target line for circulating the stored water in the hot water tank 30. The first heating device 10 and the second heating device 20 heat the water W1 as circulating water flowing through the circulation line L30. Here, the configuration in which the first heating device 10 and the second heating device 20 are arranged in parallel in the circulation line L30 is the same as in the third embodiment, and therefore a description thereof will be omitted.

[0334] Hereinafter, an example of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0335] <<Control of the first heating mode>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0336] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, the first circulation pump is stopped, and the first water supply pump 55A is stopped.

[0337] [2] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0338] [3] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, the second circulation pump is stopped, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0339] [4] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B, drive the second circulation pump, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. The first feedwater pump 55A continues to be driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to the first target temperature (e.g., 70°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (e.g., 70°C).

[0340] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0341] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the first heating device 10 is performed.

[0342] [2] When the detected water level reaches or exceeds the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, the second circulation pump is stopped, and the first feedwater pump 55A is stopped.

[0343] [3] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, drive the second circulation pump, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. During independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes fuel consumption of the second heating device 20. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be taken out.

[0344] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0345] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the second heating device 20 is performed.

[0346] [2] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, the first circulation pump is stopped, and the first water supply pump 55A is stopped.

[0347] [3] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes power consumption of the first heating device 10. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be extracted.

[0348] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0349] [1] When the detected water level reaches or exceeds the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, the second circulation pump is stopped, and the first feedwater pump 55A is stopped.

[0350] [2] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, drive the second circulation pump, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. During the independent operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (for example, 70° C.).

[0351] [3] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, the first circulation pump is stopped, and the second water supply pump 55B is stopped. The first water supply pump 55A continues to operate.

[0352] [4] When the detected water level falls below the set water level L3, water supply at the second flow rate and operation of the first heating device 10 are started. Specifically, the second water supply pump 55B is driven, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. The first water supply pump 55A continues to be driven. During the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the second heating device 20 (i.e., raising the output ratio) and lowering the outlet temperature of the first heating device 10 (i.e., lowering the output ratio) more than in the first heating mode, it is possible to suppress the power consumption of the first heating device 10 while performing the cooperative operation.

[0353] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0354] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, the first circulation pump is stopped, and the first water supply pump 55A is stopped.

[0355] [2] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0356] [3] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the burner of the hot water boiler 21 is stopped, the second sub-circulation pump 23 is stopped, the second circulation pump is stopped, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0357] [4] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B, drive the second circulation pump, drive the second sub-circulation pump 23, and operate the burner of the hot water boiler 21. The first feedwater pump 55A continues to be driven. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the first heating device 10 (i.e., increasing the output ratio) and lowering the outlet temperature of the second heating device 20 (i.e., decreasing the output ratio) more than in the first heating mode, it is possible to promote power consumption of the first heating device 10 while performing the cooperative operation.

[0358] Tenth embodiment Next, a tenth embodiment will be described. Fig. 10 is a diagram showing a schematic configuration of a hot water producing system 1 in this embodiment. In this embodiment, the same components as those in the seventh embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment directly uses the heated service water W1 as washing water or the like (that is, outputs heated water).

[0359] As shown in FIG. 10, the water supply line L50 of the hot water producing system 1 of this embodiment is not branched and is connected to the hot water tank 30. The first heating device 10 heats the water W1 flowing through the water supply line L50 as the line to be heated. The second heating device 20 heats the water W1 as stored water in the hot water tank 30. Here, the configuration in which the first heating device 10 heats the water W1 flowing through the line to be heated (water supply line L50) and the configuration in which the second heating device 20 heats the water W1 as stored water in the hot water tank are the same as those in the fourth embodiment, and therefore description thereof will be omitted.

[0360] Hereinafter, an example of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0361] <<Control of the first heating mode>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0362] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first water supply pump 55A is stopped.

[0363] [2] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0364] [3] When the detected water level becomes equal to or higher than the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0365] [4] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B and open the steam supply valve 26 to operate the steam heater 25. The first feedwater pump 55A continues to be driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a first target temperature difference (e.g., 30°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C).

[0366] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0367] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the first heating device 10 is performed.

[0368] [2] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25, and the first feedwater pump 55A is stopped.

[0369] [3] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, open the steam supply valve 26, and operate the steam heater 25. During independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes fuel consumption of the second heating device 20. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be taken out.

[0370] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0371] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the second heating device 20 is performed.

[0372] [2] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the first water supply pump 55A is stopped.

[0373] [3] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes power consumption of the first heating device 10. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be extracted.

[0374] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0375] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25, and the first feedwater pump 55A is stopped.

[0376] [2] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, open the steam supply valve 26, and operate the steam heater 25. During the independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (for example, 70° C.).

[0377] [3] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the second water supply pump 55B is stopped. The first water supply pump 55A continues to operate.

[0378] [4] When the detected water level falls below the set water level L3, water supply at the second flow rate and operation of the first heating device 10 are started. Specifically, the second water supply pump 55B is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. The first water supply pump 55A continues to be driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a second target temperature difference (e.g., 25°C). Also, during the coordinated operation of the second heating device 20, the opening degree of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C). By lowering the inlet / outlet temperature difference of the first heating device 10 compared to the first heating mode (i.e., lowering the output ratio), it is possible to suppress power consumption while performing coordinated operation with the second heating device 20.

[0379] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0380] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, and the 21st water supply pump is stopped.

[0381] [2] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0382] [3] When the detected water level becomes equal to or higher than the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0383] [4] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B and open the steam supply valve 26 to operate the steam heater 25. The first feedwater pump 55A continues to be driven. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature difference (e.g., 35°C). Also, during the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a second target temperature (e.g., 70°C). By increasing the inlet / outlet temperature difference of the first heating device 10 more than in the first heating mode (i.e., increasing the output ratio), it is possible to promote power consumption while performing cooperative operation with the second heating device 20.

[0384] Eleventh embodiment Next, an eleventh embodiment will be described. Fig. 11 is a diagram showing a schematic configuration of a hot water producing system 1 in this embodiment. In this embodiment, the same components as those in the tenth embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment directly uses the heated water W1 as cleaning water or the like (i.e., hot water output).

[0385] As shown in FIG. 11, the first heating device 10 is not arranged in the water supply line L50 of the hot water producing system 1 of this embodiment. The hot water producing system 1 of this embodiment includes a first circulation line L31 as a heating target line for circulating the stored water in the hot water tank 30. The first heating device 10 heats the water W1 as the circulating water flowing through the first circulation line L31. The second heating device 20 heats the water W1 as the stored water in the hot water tank 30, as in the tenth embodiment. Here, the configuration in which the first heating device 10 heats the water W1 as the circulating water flowing through the first circulation line L31 is the same as in the fifth embodiment, and therefore will not be described.

[0386] Hereinafter, an example of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0387] <<Control of the first heating mode>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0388] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, the first circulation pump is stopped, and the first water supply pump 55A is stopped.

[0389] [2] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0390] [3] When the detected water level becomes equal to or higher than the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0391] [4] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B and open the steam supply valve 26 to operate the steam heater 25. The first feedwater pump 55A continues to be driven. During the coordinated operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to the first target temperature (e.g., 70°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to the first target temperature (e.g., 70°C).

[0392] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0393] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the first heating device 10 is performed.

[0394] [2] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25, and the first feedwater pump 55A is stopped.

[0395] [3] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, open the steam supply valve 26, and operate the steam heater 25. During independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes fuel consumption of the second heating device 20. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be taken out.

[0396] <<Control of the third heating mode A>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0397] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the second heating device 20 is performed.

[0398] [2] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, the first circulation pump is stopped, and the first water supply pump 55A is stopped.

[0399] [3] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes power consumption of the first heating device 10. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be extracted.

[0400] <<Control of second heating mode B>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0401] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the second heating device 20 are terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25, and the first feedwater pump 55A is stopped.

[0402] [2] When the detected water level falls below the set water level L2, start supplying water at the first flow rate and operating the second heating device 20. Specifically, drive the first feedwater pump 55A, open the steam supply valve 26, and operate the steam heater 25. During the independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (eg, 70° C.).

[0403] [3] When the detected water level reaches or exceeds the set water level L2, the water supply at the second flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, the first circulation pump is stopped, and the second water supply pump 55B is stopped. The first water supply pump 55A continues to operate.

[0404] [4] When the detected water level falls below the set water level L3, water supply at the second flow rate and operation of the first heating device 10 are started. Specifically, the second water supply pump 55B is driven, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. The first water supply pump 55A continues to be driven. During the cooperative operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a third target temperature (e.g., 60°C). By raising the heat storage temperature TC by the second heating device 20 (i.e., raising the output ratio) and lowering the outlet temperature of the first heating device 10 (i.e., lowering the output ratio) more than in the first heating mode, it is possible to suppress the power consumption of the first heating device 10 while performing the cooperative operation.

[0405] <<Control of the third heating mode B>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0406] [1] When the detected water level becomes equal to or higher than the set water level L1, the water supply at the first flow rate and the operation of the first heating device 10 are terminated. Specifically, the refrigerant compressor of the heat pump 11 is stopped, the first sub-circulation pump 13 is stopped, the first circulation pump is stopped, and the first water supply pump 55A is stopped.

[0407] [2] When the detected water level falls below the set water level L2, water supply at the first flow rate and operation of the first heating device 10 are started. Specifically, the first water supply pump 55A is driven, the first circulation pump is driven, the first sub-circulation pump 13 is driven, and the refrigerant compressor of the heat pump 11 is driven. During the independent operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (eg, 70° C.).

[0408] [3] When the detected water level becomes equal to or higher than the set water level L2, the water supply at the second flow rate and the operation of the second heating device 20 are terminated. Specifically, the steam supply valve 26 is closed to stop the steam heater 25, and the second feedwater pump 55B is stopped. The first feedwater pump 55A continues to operate.

[0409] [4] When the detected water level falls below the set water level L3, start supplying water at the second flow rate and operating the second heating device 20. Specifically, drive the second feedwater pump 55B and open the steam supply valve 26 to operate the steam heater 25. The first feedwater pump 55A continues to be driven. During the cooperative operation of the first heating device 10, the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 80°C). Also, during the cooperative operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to a third target temperature (e.g., 60°C). By raising the outlet temperature of the first heating device 10 (i.e., increasing the output ratio) and lowering the heat storage temperature TC by the second heating device 20 (i.e., decreasing the output ratio) more than in the first heating mode, it is possible to promote power consumption of the first heating device 10 while performing the cooperative operation.

[0410] Twelfth embodiment Next, a twelfth embodiment will be described. Fig. 12 is a diagram showing a schematic configuration of a hot water production system 1 in this embodiment. In this embodiment, the same components as those in the tenth embodiment are given the same reference numerals, and the description thereof may be omitted. The load equipment 200 in this embodiment directly uses the heated service water W1 as washing water or the like (that is, outputs heated water).

[0411] As shown in FIG. 12, the water supply line L50 of the hot water production system 1 of this embodiment is branched on the way, and a plurality of first heating devices 10 are arranged in parallel. The plurality of first heating devices 10 arranged in parallel heat the water W1 flowing through the water supply line L50. In this embodiment, the first heating device group as the first heating device 10 is composed of the first unit 10A, the second unit 10B, and the third unit 10C. The second heating device 20 heats the water W1 as the water stored in the hot water tank 30, as in the tenth embodiment. Here, the configuration in which the plurality of first heating devices 10 arranged in parallel heat the water W1 flowing through the heating target line (water supply line L50) is the same as in the sixth embodiment, so the description will be omitted. A water supply pump 55 capable of inverter-controlling the rotation speed (drive frequency) is installed in the water supply line L50. The water supply pump 55 supplies water at a first flow rate < second flow rate < third flow rate < fourth flow rate under inverter control. A flow meter 56 may be installed in the water supply line L50 to detect the flow rate through the water supply line L50.

[0412] The collective control of the first heating device group involves starting and stopping operation of all the devices at the same time, and the control of each heating mode conforms to the tenth embodiment. The control of the number of devices in the first heating device group follows the control explanation for each heating mode below. For example, the water level in the hot water tank 30 is detected and compared with the five-stage set water level "L1>L2>L3>L4>L5", and the water supply flow rate is adjusted in four stages. The control of the number of devices in the first heating device group increases or decreases the number of operating devices according to the detected water level (i.e., the water supply flow rate).

[0413] Hereinafter, examples of control of each heating mode by the operation control unit 120 in this embodiment will be described.

[0414] <<Control of the first heating mode: Controlling the number of units in the first heating device group>> As described above, when power demand adjustment is not performed, the first heating mode is selected by the heating mode selection unit 110. Hereinafter, an example of control by the operation control unit 120 in the first heating mode will be described.

[0415] [1] When the detected water level is equal to or higher than the set water level L1, the operation of the first heating device 10A (unit 1) is terminated and the feedwater pump is stopped. When the detected water level is lower than the set water level L2, the feedwater pump is driven at the first flow rate and the operation of the first heating device 10A (unit 1) is started. When the detected water level is equal to or higher than the set water level L2, the operation of the first heating device 10B (unit 2) is terminated and the feedwater pump is shifted from the second flow rate to the first flow rate. When the detected water level is lower than the set water level L3, the feedwater pump is shifted from the first flow rate to the second flow rate and the operation of the first heating device 10B (unit 2) is started. When the detected water level is equal to or higher than the set water level L3, the operation of the first heating device 10C (unit 3) is terminated and the feedwater pump is shifted from the third flow rate to the second flow rate. When the detected water level falls below the set water level L4, the feedwater pump is shifted from the second flow rate to the third flow rate, and the first heating device 10C (Unit No. 3) starts operating. During independent operation of the first heating device 10 (i.e., any one of units 1 to 3 is operating), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (e.g., 70°C).

[0416] [2] When the detected water level is equal to or higher than the set water level L4, the operation of the second heating device 20 is terminated (the steam supply valve 26 is closed and the steam heater 25 is stopped) and the feedwater pump is shifted from the fourth flow rate to the third flow rate. When the detected water level is lower than the set water level L5, the feedwater pump is shifted from the third flow rate to the fourth flow rate and the operation of the second heating device 20 is started (the steam supply valve 26 is opened and the steam heater 25 is operated). During the coordinated operation of the first heating device 10 (i.e., all of the first to third units are in operation), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a first target temperature difference (e.g., 30°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C).

[0417] <<Control of second heating mode A>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode A will be described.

[0418] [1] In the second heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the first heating device 10 is performed.

[0419] [2] When the detected water level is equal to or higher than the set water level L1, the operation of the second heating device 20 is terminated (the steam supply valve 26 is closed and the steam heater 25 is stopped). When the detected water level is lower than the set water level L4, the water supply pump is driven at the third flow rate and the operation of the second heating device 20 is started (the steam supply valve 26 is opened and the steam heater 25 is operated). During independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a second target temperature (e.g., 90°C). By making the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is also satisfied while continuing independent operation that promotes fuel consumption of the second heating device 20. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be taken out.

[0420] <<Control of the third heating mode A: Controlling the number of units in the first heating device group>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode A will be described.

[0421] [1] In the third heating mode A, the target temperature of the hot water supply is increased to increase the amount of heat stored in the system. In this heating mode, no coordinated operation with the second heating device 20 is performed.

[0422] [2] When the detected water level is equal to or higher than the set water level L1, the operation of the first heating device 10A (unit 1) is terminated and the feedwater pump is stopped. When the detected water level is lower than the set water level L2, the feedwater pump is driven at the first flow rate and the operation of the first heating device 10A (unit 1) is started. When the detected water level is equal to or higher than the set water level L2, the operation of the first heating device 10B (unit 2) is terminated and the feedwater pump is shifted from the second flow rate to the first flow rate. When the detected water level is lower than the set water level L3, the feedwater pump is shifted from the first flow rate to the second flow rate and the operation of the first heating device 10B (unit 2) is started. When the detected water level is equal to or higher than the set water level L3, the operation of the first heating device 10C (unit 3) is terminated and the feedwater pump is shifted from the third flow rate to the second flow rate. When the detected water level falls below the set water level L4, the feedwater pump is shifted from the second flow rate to the third flow rate, and the first heating device 10C (Unit No. 3) starts operating. During independent operation of the first heating device 10 (i.e., any one of the first to third units is in operation), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a second target temperature (e.g., 90°C). By setting the heat storage temperature TC of the hot water tank 30 higher than in the first heating mode, the peak demand of the load equipment 200 is satisfied while continuing independent operation that promotes power consumption of the first heating device 10. Since the load equipment 200 mixes high-temperature water and room-temperature water to adjust the temperature to an appropriate level, a higher heat storage temperature TC allows more hot water at the required temperature to be taken out.

[0423] <<Control of second heating mode B: Control of the number of units in the first heating device group>> As described above, the second heating mode is selected by the heating mode selection unit 110 when power demand adjustment for suppressing power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the second heating mode B will be described.

[0424] [1] When the detected water level is equal to or higher than the set water level L1, the operation of the second heating device 20 is terminated (the steam supply valve 26 is closed and the steam heater 25 is stopped) and the feedwater pump is stopped. When the detected water level is lower than the set water level L2, the feedwater pump is driven at the first flow rate and the operation of the second heating device 20 is started (the steam supply valve 26 is opened and the steam heater 25 is operated). During the independent operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the first target temperature (for example, 70° C.).

[0425] [2] When the detected water level is equal to or higher than the set water level L2, the operation of the first heating device 10A (unit 1) is terminated, and the feedwater pump is shifted from the second flow rate to the first flow rate. When the detected water level is less than the set water level L3, the feedwater pump is shifted from the first flow rate to the second flow rate, and the operation of the first heating device 10A (unit 1) is started. When the detected water level is equal to or higher than the set water level L3, the operation of the first heating device 10B (unit 2) is terminated, and the feedwater pump is shifted from the third flow rate to the second flow rate. When the detected water level is less than the set water level L4, the feedwater pump is shifted from the second flow rate to the third flow rate, and the operation of the first heating device 10B (unit 2) is started. When the detected water level is equal to or higher than the set water level L4, the operation of the first heating device 10C (unit 3) is terminated, and the feedwater pump is shifted from the fourth flow rate to the third flow rate. When the detected water level falls below the set water level L5, the feedwater pump is shifted from the third flow rate to the fourth flow rate, and the first heating device 10C (Unit No. 3) starts operating. During the coordinated operation of the first heating device 10 (i.e., any one of the first to third units is operating), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the inlet / outlet temperature difference of the first sub-heat exchanger 12 converges to a second target temperature difference (e.g., 25°C). Also, during the coordinated operation of the second heating device 20, the opening of the steam supply valve 26 of the steam heater 25 is adjusted so that the heat storage temperature TC of the hot water tank 30 converges to a first target temperature (e.g., 70°C). By lowering the inlet / outlet temperature difference of the first heating device 10 compared to the first heating mode (i.e., lowering the output ratio), it is possible to suppress power consumption while performing coordinated operation with the second heating device 20.

[0426] <<Control of the third heating mode B: Controlling the number of units in the first heating device group>> As described above, the third heating mode is selected by the heating mode selection unit 110 when power demand adjustment for promoting power consumption is performed. Hereinafter, an example of control by the operation control unit 120 in the third heating mode B will be described.

[0427] [1] When the detected water level is equal to or higher than the set water level L1, the operation of the first heating device 10A (unit 1) is terminated and the feedwater pump is stopped. When the detected water level is lower than the set water level L2, the feedwater pump is driven at the first flow rate and the operation of the first heating device 10A (unit 1) is started. When the detected water level is equal to or higher than the set water level L2, the operation of the first heating device 10B (unit 2) is terminated and the feedwater pump is shifted from the second flow rate to the first flow rate. When the detected water level is lower than the set water level L3, the feedwater pump is shifted from the first flow rate to the second flow rate and the operation of the first heating device 10B (unit 2) is started. When the detected water level is equal to or higher than the set water level L3, the operation of the first heating device 10C (unit 3) is terminated and the feedwater pump is shifted from the third flow rate to the second flow rate. When the detected water level falls below the set water level L4, the feedwater pump is shifted from the second flow rate to the third flow rate, and the first heating device 10C (Unit No. 3) starts operating. During independent operation of the first heating device 10 (i.e., any one of units 1 to 3 is operating), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to a first target temperature (e.g., 70°C).

[0428] [2] When the detected water level is equal to or higher than the set water level L4, the feedwater pump is shifted from the fourth flow rate to the third flow rate, and the operation of the second heating device 20 is terminated (the steam supply valve 26 is closed and the steam heater 25 is stopped). When the detected water level is lower than the set water level L3, the feedwater pump is shifted from the third flow rate to the fourth flow rate, and the operation of the second heating device 20 is started (the steam supply valve 26 is opened and the steam heater 25 is operated). During the coordinated operation of the first heating device 10 (i.e., all of the first to third units are in operation), the rotation speed of the refrigerant compressor of the heat pump 11 is adjusted so that the outlet temperature TA of the first sub-heat exchanger 12 converges to the third target temperature difference (e.g., 35°C). Also, during the coordinated operation of the second heating device 20, the combustion amount of the burner of the hot water boiler 21 is adjusted so that the outlet temperature TB of the second sub-heat exchanger 22 converges to the second target temperature (e.g., 70°C). By increasing the inlet / outlet temperature difference of the first heating device 10 more than in the first heating mode (i.e., increasing the output ratio), it is possible to promote power consumption while performing coordinated operation with the second heating device 20.

[0429] The hot water producing system 1 of the above-described embodiment provides the following advantages.

[0430] (1) The hot water producing system 1 is a hot water producing system that heats water to be used in a load facility 200 in a business establishment, and includes a first heating device 10 that heats the water with an electric heat pump 11, a second heating device 20 that heats the water with a combustion boiler 21, a heating mode selection means 110 (heating mode selection unit 110) that selects one of a plurality of heating modes depending on whether or not power demand adjustment is performed, and a control means 120 (operation control unit 120) that controls the operation of the first heating device 10 and the second heating device 20 depending on the heating mode selected by the heating mode selection means 110. This makes it possible to provide a hot water producing system 1 that can perform optimal water heating depending on whether or not power demand adjustment is performed while compensating for the shortcomings of an electric heat pump.

[0431] The system is configured to combine a first heating device 10 using an electric heat pump 11 with a second heating device 20 using a combustion boiler 21 (hot water boiler or steam boiler) and operate in one of several heating modes. By selecting the optimal heating mode according to the power supply situation of the retail electricity supplier, VPP supplier, private power generation facility, etc., hot water can be produced stably. Furthermore, the combustion boiler 21 has a larger heating capacity by combustion energy and a higher instantaneous heat output than the electric heat pump 11. Therefore, in the heating mode in which the first heating device 10 and the second heating device 20 are used together, it is possible to supply heat by taking advantage of the advantages of the electric heat pump 11 and the combustion boiler 21.

[0432] (2) In the hot water producing system 1 of (1), the multiple heating modes include a first heating mode, a second heating mode A, and a third heating mode A, and the heating mode selection means 110 selects the first heating mode when power demand adjustment is not performed, selects the second heating mode A when power demand adjustment is performed to suppress power consumption, and selects the third heating mode A when power demand adjustment is performed to promote power consumption, and the control means 120 selects the hot water demand in the load equipment 200, the load Depending on the heat demand in the equipment 200 or the heat output of the first heating device 10, switching is performed between independent operation of the first heating device 10 and coordinated operation of the first heating device 10 and the second heating device 20. In the second heating mode A, the second heating device 20 is operated independently in response to the hot water demand in the load equipment 200 or the hot water demand in the load equipment 200. In the third heating mode A, the first heating device 10 is operated independently in response to the hot water demand in the load equipment 200 or the hot water demand in the load equipment 200.

[0433] In the first heating mode, hot water is produced by switching between independent operation of the first heating device 10 and cooperative operation (joint operation) of the first heating device 10 and the second heating device 20. During periods when electricity rates are set appropriately, the first heating device 10 is operated as a base load device and the second heating device 20 is operated as a peak load device, thereby improving the responsiveness of heat supply to changes in demand in the load facility 200 and simultaneously minimizing running costs and CO2 emissions. In the second heating mode A, the second heating device 20 is operated alone to produce hot water. During periods of rising electricity rates, the second heating device 20 is operated as a base load device and a peak load device to utilize combustion energy and limit power consumption, thereby reducing running costs while allowing for a temporary increase in CO2 emissions. In the third heating mode A, the first heating device 10 is operated alone to produce hot water. During periods of reduced electricity rates, the first heating device 10 can be operated as a base load device and a peak load device to utilize electric energy and limit fuel consumption, thereby simultaneously reducing running costs and CO2 emissions.

[0434] (3) In the hot water producing system 1 of (1), the multiple heating modes include a first heating mode, a second heating mode B, and a third heating mode B. The heating mode selection means 110 selects the first heating mode when power demand adjustment is not performed, selects the second heating mode B when power demand adjustment is performed to suppress power consumption, and selects the third heating mode B when power demand adjustment is performed to promote power consumption. In the first heating mode, the control means 120 switches between the independent operation of the first heating device 10 and the cooperative operation of the first heating device 10 and the second heating device 20 according to the hot water demand in the load equipment 200, the heat demand in the load equipment 200, or the heat output of the first heating device 10, and in the second heating mode B, switches between the independent operation of the second heating device 20 and the cooperative operation of the second heating device 20 and the first heating device 1 according to the hot water demand in the load equipment 200 or the heat demand in the load equipment 200. In the third heating mode B, switching between independent operation of the first heating device 10 and cooperative operation of the first heating device 10 and the second heating device 20 is performed according to the hot water demand in the load equipment 200 or the heat demand in the load equipment 200, and in the third heating mode B, switching between independent operation of the first heating device 10 and cooperative operation of the first heating device 10 and the second heating device 20 is performed according to the hot water demand in the load equipment 200 or the heat demand in the load equipment 200, and in the cooperative operation of the third heating mode B, switching between independent operation of the first heating device 10 and cooperative operation of the first heating device 10 and the second heating device 20 is performed, and in the cooperative operation of the third heating mode B, the electric heat pump 11 and the combustion boiler 21 are controlled so that the output ratio of the first heating device 10 to the total heat output of the first heating device 10 and the second heating device 20 is greater than the output ratio of the first heating device 10 in the cooperative operation of the first heating mode.

[0435] In the first heating mode, hot water is produced by switching between independent operation of the first heating device 10 and cooperative operation (joint operation) of the first heating device 10 and the second heating device 20. During periods when electricity rates are set appropriately, the first heating device 10 is operated as a base load device and the second heating device 20 is operated as a peak load device, thereby improving the responsiveness of heat supply to changes in demand in the load facility 200 and simultaneously minimizing running costs and CO2 emissions. In the second heating mode B, hot water is produced by switching between the independent operation of the second heating device 20 and the cooperative operation of the second heating device 20 and the first heating device 10. During the period of increasing electricity rates, the second heating device 20 is operated as a base load device and the first heating device 10 is operated as a peak load device, and the power consumption is limited by utilizing combustion energy, thereby allowing a temporary increase in CO2 emissions and reducing running costs. In addition, in the cooperative operation of the second heating mode B, the output ratio of the second heating device 20, which is a base load device, is increased compared to the first heating mode, and most of the heat is supplied by the combustion boiler 21 to the peak demand of the load equipment 200. On the other hand, the electric heat pump 11 is operated to supplement only a portion of the heat to the peak demand, so that the power consumption of the system can be minimized. In the third heating mode B, hot water is produced by switching between independent operation of the first heating device 10 and cooperative operation of the first heating device 10 and the second heating device 20. During the period of lowering the price setting of electricity rates, the first heating device 10 is operated as a base load device and the second heating device 20 is operated as a peak load device, and fuel consumption is limited by utilizing electric energy, thereby reducing running costs and CO2 emissions at the same time. In addition, in the cooperative operation of the third heating mode B, the output ratio of the first heating device 10, which is a base load device, is operated at a higher rate than in the first heating mode, and most of the heat is supplied by the electric heat pump 11 to the peak demand of the load equipment 200. On the other hand, the combustion boiler 21 is operated to supplement only a portion of the heat to the peak demand, so that the power consumption of the system can be maximized.

[0436] (4) In the hot water producing system 1 of (1), the multiple heating modes include a first heating mode, a second heating mode B, and a third heating mode A, and the heating mode selection means 110 selects the first heating mode when power demand adjustment is not performed, selects the second heating mode B when power demand adjustment is performed to suppress power consumption, and selects the third heating mode A when power demand adjustment is performed to promote power consumption, and the control means 120 switches between independent operation of the first heating device 10 and cooperative operation of the first heating device 10 and the second heating device 20 in accordance with the hot water demand in the load equipment 200, the heat demand in the load equipment 200, or the heat output of the first heating device 10 in the first heating mode. In the second heating mode B, the second heating device 20 is operated independently and the second heating device 20 and the first heating device 10 are operated in coordination with each other depending on the demand for hot water in the load equipment 200 or the demand for heat in the load equipment 200. In the coordinated operation of the second heating mode B, the electric heat pump 11 and the combustion boiler 21 are controlled so that the output ratio of the second heating device 20 to the total heat output of the first heating device 10 and the second heating device 20 is greater than the output ratio of the second heating device 20 in the coordinated operation of the first heating mode. In the third heating mode A, the first heating device 10 is operated independently depending on the demand for hot water in the load equipment 200 or the demand for heat in the load equipment 200.

[0437] In the first heating mode, hot water is produced by switching between independent operation of the first heating device 10 and cooperative operation (joint operation) of the first heating device 10 and the second heating device 20. During periods when electricity rates are set appropriately, the first heating device 10 is operated as a base load device and the second heating device 20 is operated as a peak load device, thereby improving the responsiveness of heat supply to changes in demand in the load facility 200 and simultaneously minimizing running costs and CO2 emissions. In the second heating mode B, hot water is produced by switching between the independent operation of the second heating device 20 and the cooperative operation of the second heating device 20 and the first heating device 10. During the period of increasing electricity rates, the second heating device 20 is operated as a base load device and the first heating device 10 is operated as a peak load device, and the power consumption is limited by utilizing combustion energy, thereby allowing a temporary increase in CO2 emissions and reducing running costs. In addition, in the cooperative operation of the second heating mode B, the output ratio of the second heating device 20, which is a base load device, is increased compared to the first heating mode, and most of the heat is supplied by the combustion boiler 21 to the peak demand of the load equipment 200. On the other hand, the electric heat pump 11 is operated to supplement only a portion of the heat to the peak demand, so that the power consumption of the system can be minimized. In the third heating mode A, the first heating device 10 is operated alone to produce hot water. During periods of reduced electricity rates, the first heating device 10 can be operated as a base load device and a peak load device to utilize electric energy and limit fuel consumption, thereby simultaneously reducing running costs and CO2 emissions.

[0438] (5) In the hot water producing system 1 of (1), the multiple heating modes include a first heating mode, a second heating mode A, and a third heating mode B. The heating mode selection means 110 selects the first heating mode when power demand adjustment is not performed, selects the second heating mode A when power demand adjustment is performed to suppress power consumption, and selects the third heating mode B when power demand adjustment is performed to promote power consumption. In the first heating mode, the control means 120 switches between the independent operation of the first heating device 10 and the cooperative operation of the first heating device 10 and the second heating device 20 according to the hot water demand in the load equipment 200, the heat demand in the load equipment 200, or the heat output of the first heating device 10. In the second heating mode A, the second heating device 20 is operated alone in response to the demand for hot water in the load equipment 200 or the demand for heat in the load equipment 200, and in the third heating mode B, the first heating device 10 is operated alone and the first heating device 10 and the second heating device 20 are switched between cooperative operation in response to the demand for hot water in the load equipment 200 or the demand for heat in the load equipment 200, and in the cooperative operation of the third heating mode B, the electric heat pump 11 and the combustion boiler 21 are controlled so that the output ratio of the first heating device 10 to the total thermal output of the first heating device 10 and the second heating device 20 is greater than the output ratio of the first heating device 10 in the cooperative operation of the first heating mode.

[0439] In the first heating mode, hot water is produced by switching between independent operation of the first heating device 10 and cooperative operation (joint operation) of the first heating device 10 and the second heating device 20. During periods when electricity rates are set appropriately, the first heating device 10 is operated as a base load device and the second heating device 20 is operated as a peak load device, thereby improving the responsiveness of heat supply to changes in demand in the load facility 200 and simultaneously minimizing running costs and CO2 emissions. In the second heating mode A, the second heating device 20 is operated alone to produce hot water. During periods of rising electricity rates, the second heating device 20 is operated as a base load device and a peak load device to utilize combustion energy and limit power consumption, thereby reducing running costs while allowing for a temporary increase in CO2 emissions. In the third heating mode B, hot water is produced by switching between independent operation of the first heating device 10 and cooperative operation of the first heating device 10 and the second heating device 20. During the period of lowering the price setting of electricity rates, the first heating device 10 is operated as a base load device and the second heating device 20 is operated as a peak load device, and fuel consumption is limited by utilizing electric energy, thereby reducing running costs and CO2 emissions at the same time. In addition, in the cooperative operation of the third heating mode B, the output ratio of the first heating device 10, which is a base load device, is operated at a higher rate than in the first heating mode, and most of the heat is supplied by the electric heat pump 11 to the peak demand of the load equipment 200. On the other hand, the combustion boiler 21 is operated to supplement only a portion of the heat to the peak demand, so that the power consumption of the system can be maximized.

[0440] (6) In the hot water producing system 1 of (2) or (5), the control means 120 controls the combustion boiler 21 so that the thermal output of the second heating device 20 in the second heating mode A is greater than the thermal output of the second heating device 20 in the first heating mode.

[0441] In the cooperative operation of the first heating mode, the combustion boiler 21 is operated at a predetermined output point to produce hot water at about 50 to 70°C. On the other hand, in the independent operation of the second heating mode A, the combustion boiler 21 is operated at a higher output point to produce hot water at about 80 to 90°C in order to prioritize the consumption of fuel instead of electricity. By actively converting fuel that can be purchased stably from the market into high-temperature thermal energy and storing the heat in the hot water tank 30, even in the independent operation of the second heating device 20, it is possible to flexibly and stably respond to not only the base demand of the load equipment 200 but also peak demand. When using high-temperature water in the load equipment 200, hot water of the required temperature can be obtained by mixing the high-temperature water with normal temperature water or by heat exchanging the high-temperature water with normal temperature water.

[0442] (7) In the hot water producing system 1 of (2) or (4), the control means 120 controls the electric heat pump 11 so that the heat output of the first heating device 10 in the third heating mode A is greater than the heat output of the first heating device 10 in the first heating mode.

[0443] In the independent operation and cooperative operation of the first heating mode, the electric heat pump 11 is driven at a predetermined output point to produce hot water at about 50 to 70°C. On the other hand, in the third heating mode A, in order to consume surplus power generated by the power supply source, the electric heat pump 11 is driven at a higher output point to produce hot water at about 80 to 90°C. By actively converting surplus power in the market into high-temperature thermal energy and storing it in the hot water tank 30, even in the independent operation of the first heating device 10, it is possible to flexibly and stably respond to not only the base demand of the load equipment 200 but also the peak demand. When using high-temperature water in the load equipment 200, hot water of the required temperature can be obtained by mixing the high-temperature water with room-temperature water or by heat exchanging the high-temperature water with room-temperature water.

[0444] In the hot water producing system 1 of (8)(1), the second heating device 20 heats the water by exchanging heat between the steam generated in the combustion boiler 21 and the water.

[0445] The combustion boiler 21 constituting the second heating device 20 can be a hot water boiler or a steam boiler. When a steam boiler is used as a heat source, the steam and the water are indirectly or directly heat exchanged to heat the water. For example, when using steam with an absolute pressure of 0.3 MPa to 2 MPa generated by a small once-through steam boiler, the saturation temperature reaches 150 to 215°C, so that the heating operation time can be shortened even when producing hot water at 80 to 90°C. As a result, the increase in CO2 emissions is suppressed.

[0446] In the hot water production system 1 of (9)(1), the combustion boiler 21 uses a fuel selected from the group consisting of hydrocarbons, hydrogen, and ammonia.

[0447] Hydrocarbon gases mainly composed of methane (city gas 13A, biogas, etc.), hydrocarbon gases mainly composed of propane, hydrogen gas, and ammonia gas can be used as gas fuels for the combustion boiler 21. In addition, as oil fuels for the combustion boiler 21, kerosene, light oil, heavy oil containing hydrocarbons, as well as bioethanol with adjusted moisture content can also be used. When using hydrogen gas or ammonia gas, there is the advantage that a decarbonized system that takes environmental conservation into consideration can be constructed since no CO2 is generated by combustion. When using biomethane or bioethanol, although CO2 is generated by combustion, a carbon-neutral system can be constructed.

[0448] Although the preferred embodiment of the hot water production system of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment and can be modified as appropriate. The present invention also includes a combination of two or more of the individual configurations of the above-mentioned embodiment. [Explanation of symbols]

[0449] 1. Hot water production system 10 1st heating device 11 Heat pump 12 First sub-heat exchanger 20 Second heating device 21 Combustion boiler (hot water boiler) 22 Second sub-heat exchanger 30 Hot Water Tank 31 Water level sensor 40 Temperature Sensor 100 Control section 110 Heating mode selection unit (heating mode selection means) 120 Operation control unit (control means) 200 load equipment L10 Water distribution line L20 Return water line L21 First heating line L22 Second heating line L30 Circulation Line L31 First Circulation Line L32 2nd circulation line L50 Water supply line L51 First water supply line L52 Second water supply line

Claims

1. A hot water production system that heats water used in load equipment within a business establishment, a first heating device that heats water by an electric heat pump; A second heating device that heats the water by a combustion boiler; a heating mode selection means for selecting one of a plurality of heating modes including at least a first heating mode and a second heating mode depending on whether or not power demand adjustment is being performed; a control means for controlling the operation of the first heating device and the second heating device in accordance with the heating mode selected by the heating mode selection means, The load facility generates a demand for hot water by directly using heated water, The heating mode selection means includes: When power demand adjustment is not performed, the first heating mode is selected; Selecting the second heating mode when implementing power demand adjustment to suppress power consumption more than when the first heating mode is selected; The control means Detecting a demand for hot water of the load equipment based on a water level of a hot water tank attached to the load equipment or a flow rate of makeup water, and operating the first heating device and the second heating device in response to the detected demand for hot water; In the first heating mode, the first heating device is a base load device and the second heating device is a peak load device, and switching is performed between an independent operation of the first heating device and a coordinated operation of the first heating device and the second heating device, thereby making the hot water supply follow the change in the hot water demand of the load equipment; In the second heating mode, the second heating device is operated independently as a base load device and a peak load device, and the combustion boiler is controlled so that the heat output of the second heating device in the second heating mode is greater than the heat output of the second heating device in the first heating mode, thereby allowing the hot water supply to follow changes in hot water demand of the load equipment. Hot water production system.

2. A hot water production system that heats water used in load equipment within a business establishment, a first heating device that heats water by an electric heat pump; A second heating device that heats the water by a combustion boiler; a heating mode selection means for selecting one of a plurality of heating modes including at least a first heating mode and a second heating mode depending on whether or not power demand adjustment is being performed; a control means for controlling the operation of the first heating device and the second heating device in accordance with the heating mode selected by the heating mode selection means, The load facility generates a demand for hot water by directly using heated water, The heating mode selection means includes: When power demand adjustment is not performed, the first heating mode is selected; Selecting the second heating mode when implementing power demand adjustment to suppress power consumption more than when the first heating mode is selected; The control means Detecting a demand for hot water of the load equipment based on a water level of a hot water tank attached to the load equipment or a flow rate of makeup water, and operating the first heating device and the second heating device in response to the detected demand for hot water; In the first heating mode, the first heating device is a base load device and the second heating device is a peak load device, and switching is performed between an independent operation of the first heating device and a coordinated operation of the first heating device and the second heating device, thereby making the hot water supply follow the change in the hot water demand of the load equipment; In the second heating mode, the second heating device is a base load device and the first heating device is a peak load device, and switching is performed between an independent operation of the second heating device and a coordinated operation of the second heating device and the first heating device, and in the coordinated operation of the second heating mode, the electric heat pump and the combustion boiler are controlled so that the output ratio of the second heating device to the total heat output of the first heating device and the second heating device is greater than the output ratio of the second heating device in the coordinated operation of the first heating mode, thereby allowing the hot water supply to follow changes in hot water demand of the load equipment. Hot water production system.

3. A hot water production system that heats water used in load equipment within a business establishment, a first heating device that heats water by an electric heat pump; A second heating device that heats the water by a combustion boiler; a heating mode selection means for selecting one of a plurality of heating modes including at least a first heating mode and a second heating mode depending on whether or not power demand adjustment is being performed; a control means for controlling the operation of the first heating device and the second heating device in accordance with the heating mode selected by the heating mode selection means, The load equipment generates heat demand by indirectly using heated water, The heating mode selection means includes: When power demand adjustment is not performed, the first heating mode is selected; Selecting the second heating mode when implementing power demand adjustment to suppress power consumption more than when the first heating mode is selected; The control means Detecting the heat demand of the load equipment based on the return temperature of the hot water in a hot water loop system formed for the load equipment or the difference between the supply temperature and the return temperature of the hot water in the hot water loop system, and operating the first heating device and the second heating device in response to the detected heat demand; In the first heating mode, the first heating device is a base load device and the second heating device is a peak load device, and the first heating device is operated independently, and the first heating device and the second heating device are operated in a coordinated manner. In this manner, the heat supply is made to follow the change in the heat demand of the load equipment. In the second heating mode, the second heating device is operated independently as a base load device and a peak load device, and the combustion boiler is controlled so that the heat output of the second heating device in the second heating mode is greater than the heat output of the second heating device in the first heating mode, thereby allowing the supply of hot heat to follow changes in the hot heat demand of the load equipment. Hot water production system.

4. A hot water production system that heats water used in load equipment within a business establishment, a first heating device that heats water by an electric heat pump; A second heating device that heats the water by a combustion boiler; a heating mode selection means for selecting one of a plurality of heating modes including at least a first heating mode and a second heating mode depending on whether or not power demand adjustment is being performed; a control means for controlling the operation of the first heating device and the second heating device in accordance with the heating mode selected by the heating mode selection means, The load equipment generates heat demand by indirectly using heated water, The heating mode selection means includes: When power demand adjustment is not performed, the first heating mode is selected; Selecting the second heating mode when implementing power demand adjustment to suppress power consumption more than when the first heating mode is selected; The control means Detecting the heat demand of the load equipment based on the return temperature of the hot water in a hot water loop system formed for the load equipment or the difference between the supply temperature and the return temperature of the hot water in the hot water loop system, and operating the first heating device and the second heating device in response to the detected heat demand; In the first heating mode, the first heating device is a base load device and the second heating device is a peak load device, and the first heating device is operated independently, and the first heating device and the second heating device are operated in a coordinated manner. In this manner, the heat supply is made to follow the change in the heat demand of the load equipment. In the second heating mode, the second heating device is a base load device and the first heating device is a peak load device, and switching is performed between an independent operation of the second heating device and a coordinated operation of the second heating device and the first heating device, and in the coordinated operation of the second heating mode, the electric heat pump and the combustion boiler are controlled so that the output ratio of the second heating device to the total heat output of the first heating device and the second heating device is greater than the output ratio of the second heating device in the coordinated operation of the first heating mode, thereby making the hot heat supply follow changes in the hot heat demand of the load equipment. Hot water production system.

5. The control means Detecting a heat output of the first heating device based on a temperature of hot water discharged from the first heating device during operation; In the first heating mode, switching between an independent operation of the first heating device and a coordinated operation of the first heating device and the second heating device is performed according to a heat output of the first heating device. The hot water producing system according to any one of claims 1 to 4.

6. A steam boiler is used as the combustion boiler constituting the second heating device, and the water is heated by direct or indirect heat exchange between the steam and the water. The hot water producing system according to any one of claims 1 to 4.

7. The combustion boiler uses a fuel selected from hydrogen, ammonia, biomethane, and bioethanol. The hot water producing system according to any one of claims 1 to 4.

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