Hot water supply system, method, program and cogeneration system

Abstract

In a hot water supply system in which an auxiliary heating device is installed away from a hot water supply device, stored thermal energy is effectively utilized. [Solution] The system includes a heat storage hot water supply device (34-1) capable of controlling the hot water temperature by exchanging heat from a heat medium (HM1) stored in a heat storage tank (6) with supply water (W), an auxiliary heating device (34-2) that receives hot water from the heat storage hot water supply device and is capable of auxiliary heating the hot water, and control units (14-1, 14-2) that monitor the temperature of the hot water from the heat storage hot water supply device supplied to the auxiliary heating device during hot water supply, compare the temperature of the heat medium with a set temperature to determine whether or not there is heat stored in the heat storage tank, and if there is heat storage, control the hot water temperature to the set temperature by the heat storage hot water supply device through heat exchange with the heat medium, or after processing to bring the hot water temperature closer to the set temperature, cause the auxiliary heating device to heat the hot water to the set temperature when the temperature of the hot water supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature.

Description

[Technical field]

[0001] The present invention relates to a heat utilization technology that utilizes thermal energy generated in a gas engine or a fuel cell for heating hot water. [Background technology]

[0002] 2. Description of the Related Art Hot water supply systems that utilize thermal energy, such as solar heat, or thermal energy generated by an engine generator or fuel cell that uses gas or the like as fuel, for heating hot water are known. In such hot water supply systems, when the amount of stored heat is insufficient to meet the heat required for hot water supply, etc., auxiliary heating is performed. For example, gas combustion heat from a burner is used as the auxiliary heat source, making it possible to supply hot water at the required temperature. Regarding such hot water supply systems, there is known one in which an auxiliary heat source unit is placed downstream of a solar hot water heater (Patent Document 1). Regarding efficient use of the auxiliary heat source, it is known that the auxiliary heat source is operated when hot water is supplied, and heat radiation to the atmosphere and fuel consumption are reduced compared to keeping the hot water tank full (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-148804 A [Patent Document 2] JP 2007-311036 A Summary of the Invention [Problem to be solved by the invention]

[0004] In some hot water supply systems, a heat storage hot water supply device that recovers and stores heat from a heat source such as an engine generator, a fuel cell, or solar heat, and an auxiliary heat source that heats the hot water supplied from the heat storage hot water supply device are each configured as separate devices. The heat storage hot water supply device and the auxiliary heat source are connected by piping, and the hot water can be heated by the auxiliary heat source based on the state of the stored thermal energy, and hot water can be supplied to the hot water supply load at a temperature that meets the hot water supply demand. However, in such a hot water supply system, the thermal storage hot water supply device and the auxiliary heat source may be placed apart from each other, for example, to secure installation space. In this case, the auxiliary heat source may be supplied with hot water whose temperature has changed from that when the hot water was supplied from the thermal storage hot water supply device due to the influence of the installation environment or climate. In a hot water supply system, for example, if the thermal storage hot water supply device and the auxiliary heat source are controlled at the same target temperature, even if the thermal storage in the thermal storage hot water supply device is sufficient, the auxiliary heat source will perform heating processing every time hot water is supplied, and the consumption of fuel gas will increase, resulting in a problem that the thermal energy of the exhaust heat source cannot be effectively used. In addition, in a hot water supply system, for example, if the outdoor temperature or the temperature of the pipe between the thermal storage hot water supply device and the auxiliary heat source is monitored, and the combustion amount of the auxiliary heat source is controlled according to the temperature state, there is a problem that the processing becomes complicated. SUMMARY OF THE PRESENT EMBODIMENT In order to solve the above problems, an object of the present invention is to effectively utilize stored thermal energy in a hot water supply system in which an auxiliary heat source is installed away from a hot water supply device. [Means for solving the problem]

[0005] In order to achieve the above object, according to one aspect of the hot water supply system of the present invention, there is provided a heat storage hot water supply device capable of controlling hot water temperature by heat exchange of heat of a heat medium stored in a heat storage tank with supply water, an auxiliary heating device that receives hot water from the heat storage hot water supply device and is capable of auxiliary heating of the hot water, and during hot water supply, a process of monitoring the temperature of hot water from the heat storage hot water supply device that is supplied to the auxiliary heating device, comparing the temperature of the heat medium with a set temperature to determine whether or not heat has been stored in the heat storage tank, and if heat has been stored, controlling the hot water temperature to the set temperature by heat exchange with the heat medium or bringing the hot water temperature closer to the set temperature, and a process of controlling the auxiliary heating device side. Difference Minute temperature information The initial value is "0" and supplying the heat from the heat storage hot water supply device to the auxiliary heating device, When the hot water temperature flowing into the auxiliary heating device is equal to or higher than the temperature obtained by subtracting a threshold value from the set temperature, The control unit includes a process for calculating the temperature difference between the hot water temperature at this time and the set temperature and comparing it with the differential temperature information, and if there is a difference, storing the temperature difference as new differential temperature information and using this new differential temperature information to adjust the hot water temperature of the heat storage hot water supply device, and a process for causing the auxiliary heating device to heat the hot water to the set temperature when the hot water temperature supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature.

[0006] In order to achieve the above object, according to one aspect of the hot water supply method of the present invention, there are provided a process in which a heat-storage hot water supply device exchanges heat of a heat medium stored in a heat storage tank with supply water to control and adjust a hot water temperature, a process in which an auxiliary heating device receives a supply of hot water from the heat-storage hot water supply device and performs auxiliary heating of the hot water, and a control unit monitors the temperature of hot water supplied from the heat-storage hot water supply device to the auxiliary heating device during hot water supply, and compares the temperature of the heat medium with a set temperature to determine whether or not heat has been stored in the heat storage tank, and if heat has been stored, controls the hot water temperature to the set temperature by heat exchange with the heat medium, or brings the hot water temperature closer to the set temperature, and a process in which the auxiliary heating device side controls the hot water temperature to the set temperature. Difference Minute temperature information The initial value is "0" and supplying the heat from the heat storage hot water supply device to the auxiliary heating device, When the hot water temperature flowing into the auxiliary heating device is equal to or higher than the temperature obtained by subtracting a threshold value from the set temperature,The method includes a process of calculating the temperature difference between the hot water temperature at this time and the set temperature and comparing it with the differential temperature information, and if there is a difference, storing the temperature difference as new differential temperature information and using this new differential temperature information to adjust the hot water temperature of the heat storage hot water supply device, and when the hot water temperature supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature, performing a process of causing the auxiliary heating device to heat the hot water to the set temperature.

[0007] In order to achieve the above object, according to one aspect of the program of the present invention, there is provided a program to be executed by a computer, the program including: a function of exchanging heat of a heat medium stored in a heat storage tank with supply water to cause a heat-storage hot water supply device to control a hot water temperature; a function of receiving hot water from the heat-storage hot water supply device and causing an auxiliary heating device to perform auxiliary heating of the hot water; a function of monitoring the temperature of hot water from the heat-storage hot water supply device supplied to the auxiliary heating device during hot water supply, and comparing the temperature of the heat medium with a set temperature to determine whether or not heat has been stored in the heat storage tank, and if heat has been stored, a process of controlling the hot water temperature to the set temperature by heat exchange with the heat medium, or a process of bringing the hot water temperature closer to the set temperature; Difference Minute temperature information The initial value is "0" and supplying the heat from the heat storage hot water supply device to the auxiliary heating device, When the hot water temperature flowing into the auxiliary heating device is equal to or higher than the temperature obtained by subtracting a threshold value from the set temperature, The system includes a function of calculating the temperature difference between the hot water temperature at this time and the set temperature and comparing it with the differential temperature information, and if there is a difference, storing the temperature difference as new differential temperature information and using this new differential temperature information to adjust the hot water temperature of the heat storage hot water supply device, and when the hot water temperature supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature, performing a process of causing the auxiliary heating device to heat the hot water to the set temperature.

[0008] In order to achieve the above object, according to one aspect of the cogeneration system of the present invention, there is provided a cogeneration system having a heat source which is at least any one of an engine, a fuel cell, and a solar heat exchanger, the cogeneration system including: a heat storage tank for storing a heat medium which has recovered heat from the heat source; a heat-storage hot water supply device capable of controlling a hot water temperature by exchanging heat of the heat medium stored in the heat storage tank with supply water; an auxiliary heating device which receives hot water from the heat-storage hot water supply device and is capable of auxiliary heating the hot water; a process for monitoring a temperature of hot water from the heat-storage hot water supply device which is supplied to the auxiliary heating device during hot water supply, and comparing a temperature of the heat medium with a set temperature to determine whether or not heat has been stored in the heat storage tank, and if heat has been stored, a process for controlling the hot water temperature to the set temperature by heat exchange with the heat medium, or a process for bringing the hot water temperature closer to the set temperature; Difference Minute temperature information The initial value is "0" and supplying the heat from the heat storage hot water supply device to the auxiliary heating device, When the hot water temperature flowing into the auxiliary heating device is equal to or higher than the temperature obtained by subtracting a threshold value from the set temperature, The control unit includes a process for calculating the temperature difference between the hot water temperature at this time and the set temperature and comparing it with the differential temperature information, and if there is a difference, storing the temperature difference as new differential temperature information and using this new differential temperature information to adjust the hot water temperature of the heat storage hot water supply device, and a process for causing the auxiliary heating device to heat the hot water to the set temperature when the hot water temperature supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature. Effect of the Invention

[0009] According to the present invention, any one of the following effects can be obtained.

[0010] (1) The exhaust heat from any of the exhaust heat sources, such as an engine, a fuel cell, or a solar heat exchanger, can be stored and effectively used for heating hot water, thereby enabling efficient use of the exhaust heat.

[0011] (2) By limiting the operation of the auxiliary heat source according to the heat storage state, it is possible to prevent unnecessary combustion of fuel gas and achieve energy savings.

[0012] (3) Hot water supply according to the set temperature can be realized regardless of the heat storage state.

[0013] (4) The auxiliary heat source controls heating based on information when the heat storage is sufficient, so that hot water can be continuously supplied at the same temperature even if the heat storage state changes.

[0014] (5) By notifying the heat storage hot water supply device of the temperature flowing into the auxiliary heat source and adjusting the hot water temperature, hot water can be supplied at a set temperature in accordance with the installation environment of the hot water supply system, and the amount of combustion of the auxiliary heat source can be reduced.

[0015] Other objects, features and advantages of the present invention will become more apparent with reference to the accompanying drawings and each embodiment. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram showing an example of a configuration of a hot water supply system according to a first embodiment; [Diagram 2] 4 is a flowchart showing an example of a hot water supply control process. [Diagram 3] FIG. 11 is a diagram showing an example of a configuration of a hot water supply system according to a second embodiment. [Figure 4] 4 is a flowchart showing an example of a hot water supply control process. [Diagram 5] FIG. 13 is a diagram illustrating an example of the configuration of a cogeneration system according to a third embodiment. [Figure 6] FIG. 4 is a diagram showing an example of a state inside the heat storage tank. [Figure 7] FIG. 2 is a diagram illustrating an example of a control unit of a cogeneration system. [Figure 8] 4 is a flowchart showing an outline of the cooperative control of the devices constituting the cogeneration system. [Figure 9] 4 is a flowchart showing an example of a heat recovery process of a fuel cell unit. [Figure 10] 4 is a flowchart showing an example of a heat-storage hot water supply process of the heat-storage hot water supply device. [Figure 11] 4 is a flowchart showing an example of a backup hot water supply process in the auxiliary heating device. [Figure 12] 13 is a flowchart showing an example of a hot water supply control process of a cogeneration system according to a fourth embodiment. [Figure 13] 4 is a flowchart showing an example of a heat-storage hot water supply process. [Figure 14] 4 is a flowchart showing an example of a backup hot water supply process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] First Embodiment

[0018] Fig. 1 shows a hot water supply system according to a first embodiment. The configuration shown in Fig. 1 is an example, and the present invention is not limited to the configuration to which the present invention pertains.

[0019] This hot water supply system 2 includes a first hot water supply unit 4-1 and a second hot water supply unit 4-2. The first hot water supply unit 4-1 has a hot water supply function of storing heat recovered from a heat source, for example, and using the stored heat to heat water and supply hot water. The second hot water supply unit is an example of an auxiliary heat source that takes in hot water discharged from the first hot water supply unit 4-1 and performs a heating process or the like so that the hot water reaches a set temperature. The first hot water supply unit 4-1 and the second hot water supply unit 4-2 are connected by a connection pipe 5. One end of this connection pipe 5 is connected to the hot water discharge section of the first hot water supply unit, and the other end is connected to the water supply section of the second hot water supply unit 4-2. The connection pipe 5 may be a straight pipe according to the arrangement interval between the first hot water supply unit 4-1 and the second hot water supply unit 4-2, or the shape and arrangement length may be set to avoid obstacles such as buildings (not shown) at the arrangement position of the hot water supply system 2.

[0020] In the hot water supply process of hot water supply system 2, the temperature of the hot water supplied from first hot water supply unit 4-1 is used as a criterion for determining whether or not to perform auxiliary heating in second hot water supply unit 4-2.

[0021] <First hot water supply unit 4-1> The first hot water supply unit 4-1 includes a heat storage tank 6 that collects and stores heat, for example, from an external heat source 8. It also includes a heat exchanger 10-1 that boils water using the heat stored in the heat storage tank 6, and a temperature detector 12-1 that monitors the water supply temperature and the state of heat storage in the heat storage tank 6. The heat storage tank 6 has a circulation pipe formed between it and the heat source 8, for example, and stores a heat medium inside the pipe to recover heat emitted from the heat source 8. The heat source 8 is a heat generating device such as an engine generator, a fuel cell, or a solar system that recovers solar heat. The heat medium is, for example, water, antifreeze, or other liquid or similar medium. In the heat storage process, for example, when a heat medium with a lower temperature than the exhaust heat from the heat source 8 is flowed from the heat storage tank 6 into the pipe, the heat medium exchanges heat with the heat generating part and is heated. The heat source 8 absorbs heat and is cooled by heat exchange with the heat medium. The heat medium that has exchanged heat is stored in the tank from the upper side of the heat storage tank 6. Furthermore, as described below, a circulation pipe is formed between the heat storage tank 6 and the heat exchanger 10-1, and the high-temperature heat medium in the heat storage tank 6 is passed through the heat exchanger 10-1. At this time, low-temperature feed water W is taken into the heat exchanger 10-1 in response to a hot water supply request, for example, and the feed water W is heated by exchanging heat with the high-temperature heat medium to generate hot water HW. The heat medium cooled by heat exchange with the feed water W is sent back to the heat source 8 and stored in heat. The first hot water supply unit 4-1 is provided with a control unit 14-1 which controls the heat recovery process for the heat source 8, the process of monitoring the heat storage state in the heat storage tank 6, the process of generating heat storage state information from the monitoring results, and the hot water supply process of supplying hot water at a predetermined temperature using the stored heat. This control unit 14-1 is provided with, for example, a storage unit 16-1, which is an example of a means for storing set temperature information set in a hot water supply request and heat storage state information in the heat storage tank 6. In addition, the control unit 14-1 notifies the second hot water supply unit 4-2 of the generated heat storage state information.

[0022] <Second hot water unit 4-2> The second hot water supply unit 4-2 includes, for example, a backup heat source unit 18 that heats hot water supplied through the connection pipe 5, a control unit 14-2 that controls the second hot water supply unit 4-2, and a temperature detection unit 12-2 that detects the temperature of the supplied hot water and the hot water dispensed from the second hot water supply unit 4-2. That is, the second hot water supply unit 4-2 may be a water heater that heats supplied water. The backup heat source unit 18 includes, for example, a combustion section 20 and a heat exchange section 10-2. The combustion unit 20 is an example of an auxiliary heat source that burns a fuel gas such as a burner to generate combustion exhaust. The heat exchange unit 10-2 is an example of a functional unit that performs heat exchange between liquids or between liquid and gas, and may exchange heat between the supplied hot water HW and the combustion exhaust of the combustion unit 20, or may be configured to heat the hot water HW via a heat medium that has exchanged heat with the combustion exhaust generated in the combustion unit 20. Control unit 14-2 includes, for example, storage unit 16-2, which stores information on the hot water temperature to be supplied from second hot water supply unit 4-2, hot water supplied from first hot water supply unit 4-1, threshold information for the set temperature of the hot water supply request, etc. Control unit 14-2 also acquires heat storage state information from control unit 14-1. The control unit 14-2 uses the hot water temperature detected by the temperature detection unit 12-2 and the heat storage state information of the heat storage tank 6 to control whether or not to perform auxiliary heating by the backup heat source unit 18. This control unit 14-2 performs the following controls.

[0023] <Control of second hot water supply unit 4-2> (1) When the heat storage in the first hot water supply unit 4-1 is insufficient to meet the hot water supply request, the backup heat source unit 18 is combusted to supplement the heating of the hot water HW from the first hot water supply unit 4-1 so that the hot water supply temperature reaches the set temperature set at the time of the hot water supply request or the hot water supply temperature set in the control unit 14-2. (2) When the heat storage of the first hot water supply unit 4-1 is sufficient for a hot water supply request, the temperature of the hot water HW supplied to the second hot water supply unit 4-2 is detected, and if the temperature of the hot water HW is equal to or higher than a range (TK) of a predetermined threshold value K relative to the set temperature T, hot water is supplied at this detected temperature without auxiliary heating. In other words, the backup heat source unit 18 is not operated by instructions from the control unit 14-2. Furthermore, the memory unit 16-2 stores the detected temperature of the hot water HW at this time as hot water supply temperature information. Note that this threshold value K may be set based on, for example, the piping length and material of the connecting pipe 5, the conditions of the installation environment, and the like, and is an example of temperature information that may decrease by passing through the connecting pipe 5. (3) Furthermore, when the heat storage in the first hot water supply unit 4-1 is sufficient and the temperature of the hot water HW does not reach the range (TK) of a predetermined threshold value K relative to the set temperature T, the backup heat source unit 18 is combusted to provide supplementary heating based on the set temperature T of the hot water supply request or the stored hot water supply temperature information.

[0024] <Hot water supply control of hot water supply system 2> Fig. 2 shows an example of hot water supply control by a hot water supply system. The process contents and process procedures shown in Fig. 2 are merely examples, and the present invention is not limited to such contents. In Fig. 2, process L1 is a process performed by the first hot water supply unit 4-1, and process L2 is a process performed by the second hot water supply unit 4-2. This hot water supply control is an example of the hot water supply program of the present disclosure. In response to a hot water supply request, the first hot water supply unit 4-1 exchanges heat with the water supply by utilizing heat in the heat storage tank 6 (step S1), and also acquires heat storage state information in the heat storage tank 6 and transmits it to the second hot water supply unit 4-2 (step S2). The heat storage state information may be acquired, for example, when hot water supply is started in response to a hot water supply request, or when there is a change in the temperature state of the heat medium in the heat storage tank 6.

[0025] Next, the second hot water supply unit 4-2 receives the heat storage state information from the first hot water supply unit 4-1 and stores it in the memory unit 16-2 (step S3), and also takes in the detected temperature of the inflowing hot water HW (step S4). The control unit 14-2 determines whether the heat storage state information and the detected temperature are equal to or higher than a threshold range for the set temperature (step S5), and outputs auxiliary heating process at the hot water supply temperature or control to stop the backup heat source unit 18 (step S6). The control unit 14-2 also stores the detected temperature of the hot water HW as the hot water supply temperature (step S7).

[0026] <Advantages of the First Embodiment>

[0027] According to this configuration, the following effects can be obtained.

[0028] (1) When the first hot water supply unit 4-1 supplies hot water at the set temperature, the backup heat source unit 18 of the second hot water supply unit 4-2 will not operate if the temperature change is within a threshold value previously assumed based on the arrangement environment of the connecting pipeline 5, etc., thereby preventing auxiliary heating each time hot water is supplied, and reducing the consumption of fuel gas.

[0029] (2) By determining whether or not to perform supplementary heating depending on the state of heat stored in the heat storage tank 6, the stored thermal energy can be utilized effectively.

[0030] (3) The second hot water supply unit 4-2 stores the detected temperature of the hot water taken in from the first hot water supply unit 4-1 as the hot water supply temperature, and controls the combustion of the backup heat source unit 18 based on this hot water supply temperature. This allows stable hot water supply processing to be performed without changing the temperature of the hot water dispensed from the load depending on whether auxiliary heating is provided or not.

[0031] (4) By setting the detected temperature of the hot water taken in from the first hot water supply unit 4-1 as the hot water supply temperature, hot water is supplied at the same temperature as when stored thermal energy is used, and excessive auxiliary heating is not performed, thereby preventing waste of fuel gas.

[0032] Second Embodiment

[0033] Fig. 3 shows an example of the configuration of a hot water supply system according to the second embodiment. In Fig. 3, the same components as those in Fig. 1 are given the same reference numerals. This hot water supply system 2 is an example of the hot water supply system, hot water supply program, and cogeneration system disclosed herein, and the inlet water temperature to the hot water supply unit 4-2 is used as the reference temperature for hot water supply control of the hot water supply system 2. This hot water supply system 2 may have a configuration similar to that shown in the first embodiment, and detailed description thereof will be omitted. In the first hot water supply unit 4-1, for example, in the storage section 16-1, heat storage state information indicating the state of the heat storage tank 6 is stored, and also set temperature information based on a hot water supply request is stored. Second hot water supply unit 4-2 stores, for example in memory section 16-2, set temperature information acquired when a hot water supply request is made, hot water supply temperature information used for the operation processing of second hot water supply unit 4-2, threshold value information, and the like. Furthermore, second hot water supply unit 4-2 notifies control unit 14-1 of first hot water supply unit 4-1 of detected temperature information, which is state information of supplied hot water HW, or differential temperature information with respect to a set temperature.

[0034] In such a configuration, the control unit 14-2 performs auxiliary heating processing by the backup heat source unit 18 using the detected temperature of the hot water HW detected by the temperature detection unit 12-2 and the heat storage state information of the heat storage tank 6, and also performs so-called feedback (FB) processing, which notifies the first hot water supply unit 4-1 that the hot water being supplied does not match the set temperature of the hot water supply request, thereby prompting adjustment of the hot water supply control. In the hot water supply system 2, for example, the following process is carried out as hot water supply control.

[0035] <Control of second hot water supply unit 4-2> (1) In response to a hot water supply request, the control unit 14-2 performs auxiliary heating by combusting the backup heat source unit 18 based on the detected temperature information of the incoming hot water HW, so that the set temperature set at the time of the hot water supply request is reached, regardless of the heat storage state of the first hot water supply unit 4-1. (2) When the heat storage in first hot water supply unit 4-1 is sufficient for the hot water supply request, control unit 14-2 notifies first hot water supply unit 4-1 of the stored detected temperature information or the difference temperature information between this detected temperature information and the set temperature information.

[0036] <Control of first hot water supply unit 4-1> (1) First hot water supply unit 4-1 generates information on the heat storage state in heat storage tank 6 and notifies second hot water supply unit 4-2 of the information. (2) If the heat storage is sufficient, the control unit 14-1 adjusts the opening of a pump and an on-off valve (not shown) so that the set temperature is reached, and generates hot water HW by exchanging heat between the high-temperature heat medium in the heat storage tank 6 and the supply water W. If the heat storage is insufficient, the control unit 14-1 heats the supply water W so that the temperature becomes as close to the set temperature as possible, and sends it to the second hot water supply unit 4-2 side. (3) When control unit 14-1 acquires the detected temperature information or the difference temperature information from second hot water supply unit 4-2, it corrects the hot water supply temperature based on the detected temperature information or the difference temperature information. That is, on the second hot water supply unit 4-2 side, the hot water supply temperature is set to the set temperature. Basically, the hot water supply temperature is equal to or greater than the set temperature.

[0037] <Hot water supply control of hot water supply system 2> Fig. 4 shows an example of hot water supply control by a hot water supply system. The process contents and process procedures shown in Fig. 4 are examples, and the present invention is not limited to such contents. In Fig. 4, process L1 shows a process performed by the first hot water supply unit 4-1, and process L2 shows a process performed by the second hot water supply unit 4-2. This hot water supply control is an example of a hot water supply control program disclosed herein.

[0038] In this hot water supply control, steps S11 to S14 are the same processes as steps S1 to S4 in FIG. 2, and the description thereof will be omitted. The second hot water supply unit 4-2 refers to the acquired heat storage state information and stores the detected temperature information or the difference temperature information (step S15). Furthermore, control unit 14-2 notifies first hot water supply unit 4-1 of the detected temperature information or the differential temperature information (step S16). When the temperature of the supplied hot water HW is lower than the set temperature, the control unit 14-2 operates the backup heat source unit 18 to heat the water, and then causes the hot water to be discharged to the load (step S17).

[0039] The first hot water supply unit 4-1 adjusts the hot water supply temperature based on the received detected temperature information or differential temperature information (step S18).

[0040] In this embodiment, the second hot water supply unit 4-2 performs auxiliary heating when there is a difference between the detected temperature of the incoming hot water HW and the hot water supply request temperature, but this is not limited to the above. For example, when the difference temperature is small, the second hot water supply unit 4-2 may perform processing such as not performing auxiliary heating or waiting for a predetermined time before performing auxiliary heating. In addition, the auxiliary heating processing is not limited to being based only on the detected temperature information, and may also use a flow sensor to determine the amount of hot water supply. In other words, when the amount of hot water supply is small and the difference temperature is small, auxiliary heating may not be performed based on the minimum combustion capacity of the backup heat source unit 18.

[0041] <Advantages of the second embodiment> According to this configuration, the following effects can be obtained.

[0042] (1) By correcting the hot water temperature at the first hot water supply unit 4-1 based on the detected temperature information on the second hot water supply unit 4-2 side, hot water supply processing can be performed taking into account the temperature drop between the hot water supply units, and the number of times the auxiliary heating process is performed can be reduced.

[0043] (2) By reducing the number of times auxiliary heating is performed and prioritizing the use of stored thermal energy, the amount of fuel gas consumed can be reduced.

[0044] (3) The hot water temperature is adjusted according to the drop in the temperature of the hot water HW between the hot water supply units, so that hot water supply processing can be performed at the required temperature in response to the installation environment of the hot water supply system 2 and seasonal temperature changes.

[0045] Third embodiment

[0046] Fig. 5 shows an example of the configuration of a cogeneration system according to the third embodiment. In Fig. 5, the same components as those in Fig. 1 are denoted by the same reference numerals. 5, the cogeneration system 30 includes a heat storage hot water supply device 34-1 which is a first hot water supply unit and an auxiliary heating device 34-2 which is an example of a second hot water supply unit as the hot water supply system 32. The cogeneration system 30 also includes a fuel cell unit 36 ​​as a heat source, for example.

[0047] The heat storage hot water supply device 34-1 has a heat storage function and a hot water supply function. The heat storage hot water supply device 34-1 is provided with a heat storage tank 6 in which a first heat medium HM1 is stored, and the heat medium HM1 flows from the lower part of the heat storage tank 6 to a heat medium circulation path 38-1, and the high-temperature heat medium HM1, which is heated by circulating it to an exhaust heat source, is returned to the upper part of the heat storage tank 6. This allows heat storage in a hierarchical state. For example, an open-type heat storage tank is used as the heat storage tank 6. The heat medium HM1 is a cooling heat medium on the exhaust heat source side, and recovers heat from the exhaust heat source and stores it in the heat storage tank 6. The heat storage tank 6 is provided with a number of temperature sensors that detect the heat medium temperatures of the upper, middle, and lower layers in the tank, and the detected temperature T1 of the temperature sensor 40-1 represents the heat medium temperature of the upper layer. With this heat storage function, the hot water supply function exchanges heat from the heat medium HM1 with the water W to supply hot water HW.

[0048] When supplying hot water, the feed water W supplied to the water supply passage 38-2 flows into the heat exchanger 42-1. At this time, by driving the circulation pump 44-1, the heat medium HM1 flows from the upper side of the heat storage tank 6 through the heat medium circulation passage 38-3 to the heat exchanger 42-1. In the heat exchanger 42-1, the heat of the heat medium HM1 is exchanged with the feed water W, and hot water HW is generated from the feed water W by the heat of the heat medium HM1. This hot water HW is supplied from the hot water supply passage 38-4 of the heat-storage hot water supply device 34-1.

[0049] A temperature sensor 40-2 for detecting the water supply temperature T2 is installed in the water supply passage 38-2, for example, at the inlet side of the heat storage hot water supply device 34-1. A mixing valve 46-1 is installed in the water supply passage 38-2, and a bypass passage 38-5 is installed to branch a part of the water supply W through the mixing valve 46-1 and flow it to the hot water supply passage 38-4 side. This allows the water supply W to be mixed with the hot water HW at a mixing ratio according to the opening ratio of the mixing valve 46-1. Therefore, if the heat amount of the heat medium HM1 in the heat storage tank 6 is equal to or greater than the heat amount required to obtain the hot water HW at the set temperature T, the hot water HW at the set temperature T can be discharged only from the hot water HW or from a mixture of the hot water HW and the water supply W, but if the heat amount is insufficient, the temperature at which the hot water HW is discharged will be lower than the set temperature T. In addition, the water supply passage 38-2 is provided with a flow rate sensor 50-1 for detecting the flow rate of the water supply W, and this detected flow rate is used for the heat exchange process between the heat medium HM1 and the water supply W. Further, the hot water supply passage 38-4 is provided with a temperature sensor 40-3 for detecting the temperature after heat exchange and a temperature sensor 40-4 for detecting the temperature of the hot water HW at the time of tapping.

[0050] The hot water supply path 38-4 of the thermal storage hot water supply device 34-1 is connected to the hot water supply path 38-7 of the auxiliary heating device 34-2 via a supply pipe 38-6, and the hot water supply path 38-4 forms a water passage that is continuous with the hot water supply path 38-7. As a result, the hot water HW discharged from the thermal storage hot water supply device 34-1 is supplied to the auxiliary heating device 34-2. For example, a bypass path 38-8 is provided in the hot water supply path 38-7, which is branched upstream of the heat exchanger 42-2 and connected downstream of the heat exchanger 42-2 via a mixing valve 46-3. At this time, if the temperature of the hot water HW flowing through the hot water supply path 38-7 is the set temperature T, auxiliary heating processing by the auxiliary heating device 34-2 is not necessary, and the hot water can be discharged from the auxiliary heating device 34-2 while maintaining that temperature. In addition, the hot water supply path 38-7 is provided with a flow rate sensor 50-2 that detects the flow rate of the hot water HW flowing into the auxiliary heating device 34-2. In the auxiliary heating process, the detected flow rate may be used to control the combustion of the burner 43 and the operation of the circulation pump 44-2.

[0051] The auxiliary heating device 34-2 includes a burner 43 that burns fuel gas, for example, as an example of a backup heat source. The heat source used for auxiliary heating may be electric heat or solar heat, in addition to the heat of the combustion exhaust gas of the burner 43. When performing auxiliary heating, the auxiliary heating device 34-2 operates a circulation pump 44-2 to circulate the second heat medium HM2 through the heat medium circulation path 38-9, and exchanges the combustion heat of the burner 43 with the heat medium HM2 in the heat exchanger 42-3. The amount of combustion heat of the burner 43 is adjusted so that the heat medium HM2 after the heat exchange has a predetermined temperature T9, for example, 80° C. The temperature of the heat medium HM2 is detected by a temperature sensor 40-9 that detects the temperature of the heat medium HM2 after the heat exchange. As a result, the heat medium HM1 is compensated for by heating the heat medium HM2 by the burner 43. In addition, the heat medium circuit 38-9 may be provided with an accumulator 52 for controlling the pressure of the heat medium HM2.

[0052] In the auxiliary heating process, when the detected temperature T6 of the temperature sensor 40-6 installed on the inlet side of the hot water supply passage 38-7 falls below the set temperature T, hot water HW is flowed into the heat exchanger 42-2, heat exchange is performed between the heat medium HM2 and the hot water HW, and the hot water HW is heated. The detected temperature T7 of the hot water HW at the outlet side of the heat exchanger 42-2 is detected by the temperature sensor 40-7. The hot water HW after the heat exchange can be mixed with the hot water HW before the heat exchange at a mixing ratio according to the opening ratio of the hot water supply passage 38-7 side and the bypass passage 38-8 side by the mixing valve 46-4. That is, if the detected temperature T7 of the hot water HW after the heat exchange is higher than the set temperature T, it is mixed with the hot water HW before the heat exchange at a predetermined mixing ratio from the bypass passage 38-8, and the mixed water HW of the set temperature T is discharged. The temperature of the mixed water HW is detected by a temperature sensor 40-8 in the hot water supply line 38-7, and this detected temperature T8 is used to adjust the opening of a mixing valve 46-4 that adjusts the mixed water HW to a set temperature T.

[0053] <Configuration of fuel cell unit 36> The fuel cell unit 36 ​​is an example of an exhaust heat source of the heat-storage hot water supply device 34-1, and is provided with a fuel cell 48 as this heat source. A heat exchanger 42-4 is provided in the fuel cell unit 36, and exhaust HM3 of the fuel cell 48 flows through an exhaust path 38-10. A heat medium circulation path 38-1 is provided in the heat exchanger 42-4. By operating the circulation pump 44-3, the heat medium HM1 circulates to the heat exchanger 42-4 and is heated by the exhaust heat of the high-temperature exhaust HM3 flowing through the exhaust path 38-10. In the heat medium circulation path 38-1, an inlet temperature T10 of the heat exchanger 42-4 is detected by a temperature sensor 40-10, and an outlet temperature T11 is detected by a temperature sensor 40-11.

[0054] The heat medium HM1 is caused to flow from the lower layer side of the heat storage tank 6 into the heat medium circulation path 38-1, and after heat exchange with exhaust heat in the heat exchanger 42-4, is returned to the upper layer side of the heat storage tank 6. This allows hierarchical heat storage of the heat medium HM1. The heat storage tank 6 is provided with multiple temperature sensors at different heights from the upper layer side to the lower layer side. The temperature sensor 40-1 detects the heat medium temperature on the uppermost layer side of the heat storage tank 6. The temperature sensor 40-5 detects the temperature of the heat medium at a position lower than the temperature sensor 40-1.

[0055] In addition, the cogeneration system 30 includes, for example, a heat storage hot water supply device control unit 60-1 that controls the heat storage hot water supply device 34-1, an auxiliary heating device control unit 60-2 that controls the auxiliary heating device 34-2, and a fuel cell unit control unit 60-3 that controls the fuel cell unit 36. Also, a remote control device 64 (FIG. 7) that communicates with each control unit to exchange command information may be included.

[0056] <Heat storage state in heat storage tank 6> FIG. 6 shows an example of the state inside the heat storage tank. The installation position of the temperature sensor 40-1 in the upper layer of the heat storage tank 6 may be set according to, for example, the heating capacity and heating speed of the heat medium HM2 that performs auxiliary heating. The position of the temperature sensor 40-1 may be at least a position where the temperature of the heat medium HM1 is detected at a volume level position where the time to complete the start-up of the burner 43 can be secured before the heat of the heat medium HM1 is used for hot water supply. For example, if the regulated flow rate of 24 [liters / min] can be heated in 10 [seconds], the temperature sensor 40-1 is set at a volume level position corresponding to a heat medium amount of 4 [liters] or more, and the heat medium temperature at that position is detected. In the figure, the dashed line X indicates an imaginary line of the watershed between the heat medium HM1 on the upper layer side and the low-temperature heat medium LHM1 on the lower layer side.

[0057] The heat storage state of the heat storage tank 6 is determined, for example, by whether or not the detected temperature T1 of the temperature sensor 40-1 is a predetermined temperature β higher than the set temperature T of the hot water supply request. In other words, the heat storage state is determined by whether or not the heat medium HM1 stored in the heat storage tank 6 is capable of supplying hot water at the set temperature T. As a result, if the detected temperature T1 is T1<(T+β), it is determined that no heat has been stored, and if T1≧(T+β), it is determined that heat has been stored.

[0058] <About the control unit> 7 shows an example of a control unit of the cogeneration system 30. This control unit 62 includes a heat-storage hot water supply device control unit 60-1, an auxiliary heating device control unit 60-2, a fuel cell unit control unit 60-3, and a remote control control unit 60-4, which are configured by a computer equipped with a communication function. The heat-storage hot water supply device control unit 60-1 is a control means for the heat-storage hot water supply device 34-1, and includes a processor 66-1, a memory unit 68-1, a system communication unit 70-1, and an input / output unit (I / O) 72-1, and controls hot water supply for the heat-storage hot water supply device 34-1. The processor 66-1 executes an OS (Operating System) and a hot water supply program in the memory unit 68-1, and cooperates with the auxiliary heating device control unit 60-2, the fuel cell unit control unit 60-3, and the remote control control unit 60-4 via the system communication unit 70-1 to execute information processing required for hot water supply control. The memory unit 68-1 includes a ROM (Read-Only Memory) and a RAM (Random-Access Memory). A storage element such as a hard disk device or a non-volatile memory that stores data is used in this memory unit 68-1. The RAM constitutes a work area for information processing. The system communication unit 70-1 communicates with the auxiliary heating device control unit 60-2, the fuel cell unit control unit 60-3, and the system communication unit on the remote control control unit 60-4 side by wire or wirelessly, and transmits and receives information necessary for control. The I / O 72-1 receives detection signals from various temperature sensors such as the temperature sensor 40-1 and the flow rate sensor 50-1 in the thermal storage hot water supply device 34-1, and outputs control signals for the mixing valve 46-1 and the circulation pump 44-1.

[0059] The auxiliary heating device control unit 60-2 is a control means for the auxiliary heating device 34-2, and includes a processor 66-2, a memory unit 68-2, a system communication unit 70-2, and an I / O 72-2, and controls hot water supply for the auxiliary heating device 34-2. The processor 66-2 executes the OS and hot water supply program stored in the memory unit 68-2, and cooperates with the thermal storage hot water supply device control unit 60-1, the fuel cell unit control unit 60-3, and the remote control control unit 60-4 via the system communication unit 70-2 to execute information processing required for hot water supply control. The memory unit 68-2 includes ROM and RAM. Storage elements such as a hard disk drive and non-volatile memory that store data are used in this memory unit 68-2. The RAM constitutes a work area for information processing. The system communication unit 70-2 communicates with the thermal storage hot water supply device control unit 60-1, the fuel cell unit control unit 60-3, and the system communication unit on the remote control control unit 60-4 side by wire or wirelessly, and transmits and receives information required for control. The I / O 72-2 receives detection signals from various temperature sensors, such as the temperature sensor 40-6 in the auxiliary heating device 34-2, and the flow rate sensor 50-2, and outputs control signals to the burner combustion control unit 74 that controls the combustion of the mixing valve 46-4, the circulating pump 44-2, and the burner 43.

[0060] The fuel cell unit control unit 60-3 is a control means for the fuel cell unit 36, and includes a processor 66-3, a memory unit 68-3, a system communication unit 70-3, and an I / O 72-3, and controls the operation of the fuel cell unit 36. The processor 66-3 executes the OS and hot water supply program stored in the memory unit 68-3, and cooperates with the thermal storage hot water supply device control unit 60-1, the auxiliary heating device control unit 60-2, and the remote control control unit 60-4 via the system communication unit 70-3 to execute information processing required for hot water supply control. The memory unit 68-3 includes ROM and RAM. Storage elements such as a hard disk drive and non-volatile memory that store data are used in this memory unit 68-3. The RAM constitutes a work area for information processing. The system communication unit 70-3 communicates with the thermal storage hot water supply device control unit 60-1, the auxiliary heating device control unit 60-2, and the system communication unit on the remote control control unit 60-4 side by wire or wirelessly, and transmits and receives information required for control. The I / O 72-3 receives detection signals from the temperature sensors 40-10, 40-11 in the fuel cell unit 36, and outputs control signals to the circulation pump 44-3 and other components 76 related to fuel cell control.

[0061] The remote control control section 60-4 is provided in a remote control device 64, and cooperates with the independent heat-storage hot water supply device control section 60-1, auxiliary heating device control section 60-2, and fuel cell unit control section 60-3 through computer communication.

[0062] <Processing procedure for linkage control> Fig. 8 shows an overview of the coordinated control of the devices constituting the cogeneration system 30. The process contents shown in Fig. 8 are an example of a hot water supply program of the hot water supply system and a control method of the cogeneration system according to the present disclosure. In this process, the remote control device 64 executes initialization at start-up (S21), input reception processing (S22), and display output processing (S23). In the input reception processing, initial settings are made by the user. This initial setting includes, for example, inputting the set hot water supply temperature T to the heat storage hot water supply device 34-1 and the auxiliary heating device 34-2, and switching the operation of the fuel cell unit 36 ​​ON / OFF. In the display output processing, input information and output information are presented on the display unit of the remote control device 64.

[0063] The fuel cell unit 36 ​​is initialized (S31) and then executes a heat recovery process (S32). The start or end of the heat recovery process is instructed by switching the operation ON / OFF from the remote control device 64.

[0064] The heat-storage hot water supply device 34-1 executes initialization (S41) and executes heat-storage hot water supply process I (S42). This heat-storage hot water supply process is an example of a hot water supply process of the present disclosure, and receives a set temperature T as setting information from the remote control device 64, and controls the outlet temperature of the hot water HW to the set temperature T. In this heat-storage hot water supply process, the auxiliary heating device 34-2 is notified of "heat storage" or "no heat storage" as heat storage state information of the heat storage tank 6. In addition, the heat-storage hot water supply device 34-1 may perform maintenance and the like as a management process.

[0065] The auxiliary heating device 34-2 executes initialization (S51) and executes auxiliary heating process I (S52). In this auxiliary heating process, the remote control device 64 provides setting information, such as set temperature T, and the heat storage state information from the heat-storage hot water supply device 34-1, such as "heat stored" or "heat not stored." The auxiliary heating device 34-2 uses the outlet hot water temperature of the heat-storage hot water supply device 34-1 as a reference, and controls execution and stop of the auxiliary heating process depending on whether heat is stored in the heat storage tank 6 and whether the temperature of the incoming hot water is a predetermined temperature difference from the set temperature T. In addition, the auxiliary heating device 34-2 may perform maintenance as a management process.

[0066] <Heat recovery processing> FIG. 9 shows the procedure of the heat recovery process of the fuel cell unit . The fuel cell unit 36 ​​determines whether operation is ON (S321), and if operation is ON (YES in S321), drives the fuel cell 48 (S322). When driving the fuel cell 48, the rotation of the circulation pump 44-3 is controlled so that the detected temperature T11 of the temperature sensor 40-11, which detects the OUT temperature after heat recovery, becomes a constant temperature, for example, 75° C. (S323). If the operation is not ON (NO in S321), the operation of the fuel cell 48 is stopped or the stopped state is maintained (S324). When the operation of the fuel cell 48 is stopped, the rotation of the circulation pump 44-3 is stopped (S325).

[0067] <Heat storage hot water treatment I> FIG. 10 shows an example of the heat-storage hot water supply process I (S42) of the heat-storage hot water supply device 34-1. The heat-storage hot water supply device control unit 60-1 judges whether or not heat is stored in the heat storage tank based on the detected temperature state in the heat storage tank 6 (step S421), and if heat is stored (YES in step S421), transmits heat storage state information of "heat stored" to at least the auxiliary heating device 34-2 (step S422). If heat is not stored (NO in step S421), transmits heat storage state information of "no heat stored" to at least the auxiliary heating device 34-2 (step S423). As described above, the heat storage state may be judged using the input set temperature T and the detected temperatures of the temperature sensors 40-1, 40-5, etc. in the heat storage tank 6.

[0068] The heat-storage hot water supply device control unit 60-1 judges whether hot water supply is being used from the detection result of the flow rate sensor 50-1 (step S424), and if hot water supply is being used (YES in step S424), the heat storage is heat exchanged with the water supply W (step S425). The heat-storage hot water supply device control unit 60-1 then judges whether the temperature T3 detected by the temperature sensor 40-3 is higher than the set temperature T (step S426) to judge whether hot water supply at the set temperature T is possible. In other words, this judgement is a judgement as to whether there is heat storage in the heat storage tank. If hot water supply at the set temperature T is possible (YES in step S426), the opening of the mixing valve 46-1 is controlled so that the temperature detected by the temperature sensor 40-4 becomes the set temperature T (step S427).

[0069] Furthermore, if hot water cannot be supplied at the set temperature T (NO in step S426), the heat-storage hot water supply device 34-1 may supply hot water to the auxiliary heating device 34-2 at a temperature as close as possible to the set temperature T (step S428). Furthermore, if hot water supply is not in use (NO in step S424), heat-storage hot water supply device control section 60-1 stops hot water supply (step S429).

[0070] In addition, the heat storage status information of the heat storage tank 6 may be transmitted when the status changes, for example, when a hot water supply request occurs, when the status inside the heat storage tank 6 changes, or when the set temperature T of the hot water supply request changes.

[0071] In addition, the heat storage hot water supply device 34-1 may transmit only detected temperature information from temperature sensors 40-1, 40-5, etc. to the auxiliary heating device 34-2 or the remote control device 64 as heat storage status information, and in this case, the determination of whether or not heat has been stored may be made by the auxiliary heating device 34-2 or the remote control device 64.

[0072] <Auxiliary Heat Treatment I> FIG. 11 shows an example of the auxiliary heating process I of the auxiliary heating device 34-2. In the auxiliary heating device control section 60-2, the set temperature T notified from the remote control device 64 as the hot water heater set temperature is set in the memory section 68-2, for example (step S521). This hot water set temperature is an example of the hot water temperature of the auxiliary heating device 34-2, and is the target temperature for hot water supply. The set temperature T is set as the initial value for this hot water set temperature. It is determined whether hot water supply is in use (step S522), and if hot water supply is in use (YES in step S522), it is determined whether the heat storage tank 6 has "heat storage" (step S523). This determination of hot water supply use may be made by, for example, referring to the detection result of the flow rate sensor 50-2. If heat storage is in use (YES in step S523), it is determined by referring to the temperature sensor 40-6 whether the detected temperature T6, which is the inlet water temperature, is equal to or greater than a predetermined threshold value K, for example, a range (TK) of 2 [°C] with respect to the set temperature T (step S524). If the inlet water temperature is equal to or higher than the range of threshold value K (YES in step S524), the inlet water temperature (T-α), which is the detected temperature T6 at this time, is stored as the hot water heater set temperature in memory unit 68-2 (step S525). The stored "α" is the difference temperature between the detected inlet water temperature T6 and the set temperature T. Note that if mixing valve 46-4 is fully open toward bypass path 38-8, the detected temperature T8 of temperature sensor 40-8 may be stored as the hot water heater set temperature.

[0073] The auxiliary heating device 34-2 then stops the heating operation or maintains the stopped state, or fully opens the mixing valve 46-4 to the bypass path 38-8 side to supply hot water HW to the hot water supply load side at the detected temperature (step S526).

[0074] In addition, if the heat storage tank 6 is "without heat storage" (NO in step S523) or if the inlet water temperature is outside the range of the threshold K (NO in step S524), it is determined whether the inlet water temperature is above the hot water heater set temperature (step S527), and if it is above the hot water heater set temperature (YES in step S527), the hot water is discharged at that temperature (step S526).If the temperature is lower (NO in step S527), the mixing valve 46-3 is controlled so that the temperature sensor 40-8 reaches the set temperature T (step S528). Furthermore, if hot water supply is not in use (NO in step S522), hot water supply is stopped (step S529).

[0075] If the inlet water temperature T6 for the auxiliary heating device 34-2 is less than the hot water heater set temperature, the heating operation is performed to make it reach the hot water heater set temperature. However, if it is at the hot water heater set temperature, the heating operation is not performed and hot water is supplied at that temperature.

[0076] <Advantages of the Third Embodiment> According to this embodiment, the following effects can be obtained.

[0077] (1) When the heat storage hot water supply device 34-1 supplies hot water at the set temperature T, if the temperature change in the hot water flow is within the range of the threshold value K previously assumed, the auxiliary heating device 34-2 does not perform auxiliary heating processing by burner combustion. This prevents the auxiliary heating processing from occurring each time hot water is supplied, and reduces the consumption of fuel gas.

[0078] (2) By determining whether or not to perform supplementary heating depending on the state of heat stored in the heat storage tank 6, the stored thermal energy can be utilized effectively.

[0079] (3) The auxiliary heating device 34-2 sets the detected temperature of the hot water taken in from the heat storage hot water supply device 34-1 as the hot water supply temperature, and controls the combustion of the burner 43 based on this hot water supply temperature. This allows stable hot water supply processing to be performed without changing the hot water supply temperature to the load depending on whether auxiliary heating is present or not.

[0080] (4) By setting the detected temperature of the hot water taken in from the auxiliary heating device 34-2 as the next hot water supply temperature, hot water is supplied at the same temperature as when the stored thermal energy is used, and excessive auxiliary heating is not performed, thereby preventing waste of fuel gas.

[0081] [Fourth embodiment]

[0082] Fig. 12 shows an overview of the coordinated control of the devices constituting the cogeneration system 30 according to the fourth embodiment. The coordinated control shown in Fig. 12 is an example of the hot water supply program of the present invention, and the present invention is not limited to such processing contents and processing procedures.

[0083] In the linked control shown in FIG. 12, control processing steps S21 to S23 of the remote control device 64 and control processing steps S31 and S32 of the fuel cell unit are similar to the processing shown in FIG. 8, so description thereof will be omitted.

[0084] The heat-storage hot water supply device 34-1 executes initialization (S41) and executes heat-storage hot water supply process II (S42). This heat-storage hot water supply process is an example of a hot water supply process of the present disclosure, and receives a set temperature T as setting information from the remote control device 64, and controls the outlet temperature of the hot water HW to the set temperature T. In this heat-storage hot water supply process, the auxiliary heating device 34-2 is notified of "heat storage" or "no heat storage" as heat storage state information of the heat storage tank 6, and the auxiliary heating device 34-2 is notified of inlet water temperature information detected by the temperature sensor 40-6, and the hot water supply temperature is adjusted based on this inlet water temperature.

[0085] In the auxiliary heating device 34-2, initialization is performed (S51), and auxiliary heating process II (S52) is executed. In this auxiliary heating process, a set temperature T is received as setting information from the remote control device 64, and the outlet temperature of the hot water HW is controlled to the set temperature T. Also, depending on the heat storage state information from the heat storage hot water supply device 34-1, "with heat storage" or "without heat storage", heating control of the hot water HW, including combustion control of the burner 43, is performed. Also, the inlet water temperature of the hot water HW supplied from the heat storage hot water supply device 34-1 is detected, and if this detected temperature does not match the set temperature T set by the remote control device 64, the inlet water temperature information is notified to the heat storage hot water supply device 34-1 side in order to correct the hot water supply temperature.

[0086] <Heat storage hot water treatment II> FIG. 13 shows an example of the heat-storage hot water supply process (S42) of the heat-storage hot water supply device 34-1. The heat-storage hot water supply device control unit 60-1 stores the set temperature T set by the remote control device 64 as the supply temperature for hot water supply from the heat-storage hot water supply device 34-1 (step S61), and judges the heat storage state in the heat storage tank 6. Steps S62 to S65 for judging the heat storage state and judging whether hot water is to be used are similar to steps S421 to S424 in Fig. 10, and a description thereof will be omitted. However, in this case, the set temperature T, which is the criterion for judging the heat storage state, is the stored supply temperature.

[0087] If hot water is being used (YES in step S65), it is checked whether inlet water temperature information has been received from the auxiliary heating device 34-2 (step S66), and if it has been received (YES in step S66), it is determined whether this inlet water temperature is lower than the set temperature T (step S67). If the inlet water temperature is lower than the set temperature T (YES in step S67), the heat-storage hot water supply device control unit 60-1 corrects the supply temperature to be higher (step S68). If the inlet water temperature is higher than the set temperature T (YES in step S69), the heat-storage hot water supply device control unit 60-1 corrects the supply temperature to be lower (step S70). This supply temperature is the hot water supply temperature of the heat-storage hot water supply device 34-1. That is, in this heat storage hot water supply process II, the cogeneration system 30 performs auxiliary heating process based on the outlet hot water temperature from the heat storage hot water supply device 34-1, and supplies hot water at the set temperature T by adjusting the outlet hot water temperature of the heat storage hot water supply device 34-1 through feedback control based on water temperature information detected by the auxiliary heating device 34-2.

[0088] The heat-storage hot water supply device 34-1 exchanges the stored heat with the water supply W at the corrected hot water supply temperature (step S71). The heat-storage hot water supply device control unit 60-1 determines whether hot water can be supplied at the set temperature T by determining whether the temperature T3 detected by the temperature sensor 40-3 is higher than the supply temperature (step S72). In other words, this determination is a determination of whether there is heat stored in the heat storage tank. If hot water can be supplied at the hot water supply temperature (YES in step S72), the mixing valve 46-1 is controlled so that the temperature T4 detected by the temperature sensor 40-4 becomes the supply temperature (step S73).

[0089] If hot water cannot be supplied at the set temperature T (NO in step S72), the heat-storage hot water supply device 34-1 controls the mixing valve 46-1 so that the temperature is as close as possible to the hot water supply temperature, and supplies hot water to the auxiliary heating device 34-2 (step S74).

[0090] Moreover, when the heat-storage hot water supply device 34-1 has not received the inlet water temperature information (NO in step S66), the process proceeds to a process of heat-exchanging the stored heat with the supply water W at the stored supply temperature (step S71).

[0091] If hot water supply is not in use (NO in step S65), hot water supply is stopped (step S75).

[0092] <Auxiliary Heat Treatment II> FIG. 14 shows an example of the auxiliary heating process II of the auxiliary heating device 34-2. In the auxiliary heating device control section 60-2, for example, in the memory section 68-2, "0" is stored as the inlet water temperature difference record (step S81). This inlet water temperature difference record is an example of the difference temperature information of the present disclosure, and is the temperature difference between the set temperature T and the inlet water temperature of the auxiliary heating device 34-2. It is a record relating to the hot water temperature, whether or not the heat storage hot water supply device 34-1 supplies hot water in the "with heat storage" state and the inlet water temperature is within a range of, for example, 2 [°C] or more with respect to the set temperature T as a threshold value K.

[0093] It is determined whether hot water is being used (step S82), and if so (YES in step S82), it is determined whether the heat storage tank 6 has "heat storage" (step S83). This determination of hot water use may be made, for example, by referring to the detection result of the flow rate sensor 50-2. If "heat storage" is present (YES in step S83), the temperature sensor 40-6 is referenced to determine whether the detected temperature T6 is equal to or greater than a predetermined threshold value K, for example, a range (TK) of 2°C with respect to the set temperature T (step S84). If the inlet water temperature is equal to or greater than the range of threshold value K (YES in step S84), the set temperature and the inlet water temperature are subtracted, and it is determined whether they match the stored inlet water temperature difference record (step S85). If the subtraction value does not match the inlet water temperature difference record (NO in step S85), this subtraction value is stored as a new inlet water temperature difference record in memory unit 68-2 (step S86), and this inlet water temperature difference record and the inlet water temperature are transmitted to heat-storage hot water supply device 34-1 as inlet water temperature information (step S87). That is, the inlet water temperature difference record is compared with the temperature difference between the set temperature and the inlet water temperature, and if there is a change, the temperature difference at that time is recorded as a new inlet water temperature difference record, and at the same time the inlet water temperature, temperature difference, etc. are transmitted to heat-storage hot water supply device 34-1 as inlet water temperature information.

[0094] If the inlet water temperature is equal to or higher than the set temperature (YES in step S88), the auxiliary heating operation is stopped (step S89). At this time, the mixing valve 46-4 is set to the bypass side. Also, if the temperature is low (NO in step S88), the mixing valve 46-4 is controlled so that the temperature sensor 40-8 reaches the set temperature T (step S90).

[0095] If there is no heat stored in the heat storage tank 6 (NO in step S83), the hot water supply process may be performed without calculating the difference in the inlet water temperature. Furthermore, if hot water supply is not in use (NO in step S82), the hot water supply may be stopped (step S91).

[0096] <Advantages of the Fourth Embodiment> According to this embodiment, the following effects can be obtained.

[0097] (1) By correcting the hot water temperature of the heat storage hot water supply device 34-1 based on the detected temperature information from the auxiliary heating device 34-2, hot water supply processing can be performed taking into account the temperature drop between the hot water supply units, and the number of times the auxiliary heating processing is performed can be reduced.

[0098] (2) By reducing the number of times auxiliary heating is performed and prioritizing the use of stored thermal energy, the amount of fuel gas consumed can be reduced.

[0099] (3) The hot water temperature of the heat storage hot water supply device 34-1 is adjusted according to the temperature drop, so that hot water supply processing can be performed at the required temperature in response to the installation environment of the hot water supply system 32 and seasonal temperature changes.

[0100] As described above, the most preferred embodiment of the present invention has been described. The present invention is not limited to the above description. Various modifications and changes are possible for those skilled in the art based on the gist of the invention described in the claims or disclosed in the description for carrying out the invention. It goes without saying that such modifications and changes are included in the scope of the present invention. [Industrial Applicability]

[0101] The hot water supply system, hot water supply program, and cogeneration system of the present invention control the execution of the auxiliary heating process based on the inlet water temperature flowing into the auxiliary heating device, and correct the control on the hot water supply device side, thereby making effective use of the recovered thermal energy and reducing waste of fuel gas, which is useful. [Explanation of symbols]

[0102] 2. Hot water system 4-1 First hot water unit 4-2 Second hot water supply unit 5 Connecting Pipes 6. Heat storage tank 8 Heat source 10-1, 10-2 Heat exchange section 12-1, 12-2 Temperature detection section 14-1, 14-2 Control section 16-1, 16-2 Storage section 18 Backup heat source unit 20 Combustion section 30 Cogeneration system 32 Hot water system 34-1 Heat storage hot water supply device 34-2 Auxiliary heating device 36 Fuel Cell Unit 38-1, 38-3, 38-9 Heat medium circulation path 38-2 Water supply channel 38-4, 38-7 Hot water supply 38-5, 38-8 Bypass Road 38-6 Supply pipe 38-10 Exhaust duct 40-1, 40-2, 40-3, 40-4, 40-5, 40-6, 40-7, 40-8, 40-9, 40-10, 40-11 Temperature sensors 42-1, 42-2 42-3, 42-4 Heat exchanger 44-1, 44-2, 44-3 Circulation pump 46-1, 46-3, 46-4 Mixing valve 48 Fuel Cell 50-1, 50-2 Flow Sensor 52 Accumulator 60-1 Heat storage hot water supply device control unit 60-2 Auxiliary heating device control unit 60-3 Fuel cell unit control section 60-4 Remote control unit 62 Control section 64 Remote Control Device

Claims

1. a heat storage hot water supply device capable of controlling the hot water temperature by exchanging heat of a heat medium stored in a heat storage tank with supply water; an auxiliary heating device that receives hot water from the heat-storage hot water supply device and is capable of auxiliary heating the hot water; During hot water supply, the temperature of hot water supplied from the heat storage hot water supply device to the auxiliary heating device is monitored, and the temperature of the heat medium is compared with a set temperature to determine whether or not heat is stored in the heat storage tank. If heat is stored, the hot water temperature is controlled to the set temperature by heat exchange with the heat medium, or the hot water temperature is brought closer to the set temperature. An initial value of difference temperature information is set to "0" on the auxiliary heating device side to supply the hot water from the heat storage hot water supply device to the auxiliary heating device, and the hot water temperature flowing into the auxiliary heating device is adjusted to the temperature of the hot water that is higher than the previous temperature. a control unit that, when the temperature is equal to or higher than the set temperature minus a threshold value, calculates the temperature difference between the hot water temperature at that time and the set temperature and compares it with the differential temperature information, and if there is a difference, stores the temperature difference as new differential temperature information and uses this new differential temperature information to adjust the hot water temperature of the heat storage hot water supply device; and, when the hot water temperature supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature, causes the auxiliary heating device to heat the hot water to the set temperature.

2. A step in which the heat storage hot water supply device exchanges heat of the heat medium stored in the heat storage tank with the supply water to control and adjust the hot water temperature; an auxiliary heating device receiving hot water from the heat storage hot water supply device and auxiliary heating the hot water; a control unit monitors the hot water temperature from the heat storage hot water supply device supplied to the auxiliary heating device during hot water supply, compares the temperature of the heat medium with a set temperature to determine whether or not heat has been stored in the heat storage tank, and if heat has been stored, controls the hot water temperature to the set temperature by heat exchange with the heat medium, or brings the hot water temperature closer to the set temperature; sets "0" as an initial value of difference temperature information on the auxiliary heating device side and supplies the hot water from the heat storage hot water supply device to the auxiliary heating device, and if the hot water temperature flowing into the auxiliary heating device is equal to or higher than a temperature obtained by subtracting a threshold value from the set temperature, calculates the temperature difference between the hot water temperature at this time and the set temperature and compares it with the difference temperature information, and if there is a difference, stores the temperature difference as new difference temperature information and uses this new difference temperature information to adjust the hot water supply temperature of the heat storage hot water supply device; and if the hot water temperature supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature, causes the auxiliary heating device to heat the hot water to the set temperature. A hot water supply method comprising:

3. A program for causing a computer to execute the program, A function of exchanging heat of the heat medium stored in the heat storage tank with the supply water to control the hot water temperature by the heat storage hot water supply device; A function of receiving hot water from the heat storage hot water supply device and causing an auxiliary heating device to perform auxiliary heating of the hot water; a function for monitoring the hot water temperature from the heat storage hot water supply device supplied to the auxiliary heating device during hot water supply, and for comparing the temperature of the heat medium with a set temperature to determine whether or not heat has been stored in the heat storage tank, and if heat has been stored, for controlling the hot water temperature to the set temperature by heat exchange with the heat medium, or for bringing the hot water temperature closer to the set temperature; for setting "0" as an initial value of differential temperature information on the auxiliary heating device side and for supplying the hot water from the heat storage hot water supply device to the auxiliary heating device, and if the hot water temperature flowing into the auxiliary heating device is equal to or higher than the temperature obtained by subtracting a threshold value from the set temperature, for calculating the temperature difference between the hot water temperature at this time and the set temperature and comparing it with the differential temperature information, and if there is a difference, for storing the temperature difference as new differential temperature information and for adjusting the hot water supply temperature of the heat storage hot water supply device using this new differential temperature information; and for performing a process for causing the auxiliary heating device to heat the hot water to the set temperature when the hot water temperature supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature. Including, the program.

4. A cogeneration system having at least one of an engine, a fuel cell, and a solar heat exchanger as a heat source, a heat storage tank for storing a heat medium that has recovered heat from the heat source; a heat storage hot water supply device capable of controlling a hot water temperature by heat exchange of the heat of the heat medium stored in the heat storage tank with supply water; an auxiliary heating device that receives hot water from the heat-storage hot water supply device and is capable of auxiliary heating the hot water; a control unit which, during hot water supply, monitors the hot water temperature from the heat storage hot water supply device supplied to the auxiliary heating device, compares the temperature of the heat medium with a set temperature to determine whether or not heat has been stored in the heat storage tank, and if heat has been stored, controls the hot water temperature to the set temperature by heat exchange with the heat medium, or brings the hot water temperature closer to the set temperature; sets "0" as an initial value of difference temperature information on the auxiliary heating device side and supplies the hot water from the heat storage hot water supply device to the auxiliary heating device, and if the hot water temperature flowing into the auxiliary heating device is equal to or higher than a temperature obtained by subtracting a threshold value from the set temperature, calculates the temperature difference between the hot water temperature at this time and the set temperature and compares it with the difference temperature information, and if there is a difference, stores the temperature difference as new difference temperature information and uses this new difference temperature information to adjust the hot water supply temperature of the heat storage hot water supply device; and, when the hot water temperature supplied from the heat storage hot water supply device to the auxiliary heating device is lower than the set temperature, causes the auxiliary heating device to heat the hot water to the set temperature. Cogeneration systems, including:

Images