Hot water supply system

Abstract

To provide a hot water supply system that is advantageous in preventing a power peak from occurring right after end of downward DR.SOLUTION: A hot water supply system according to the present disclosure comprises: a hot water storage tank; a plurality of heat source units connected to the hot water storage tank; control means for controlling the operation of the plurality of heat source units; and communication means capable of receiving a power consumption reduction instruction. For a predetermined time after end of power the consumption reduction instruction, a predetermined percentage of a required heating capacity is evenly distributed to a selected number of heat source units from the plurality of heat source units, thereby setting a target heating capacity per heat source unit and performing boiling operation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a hot water supply system.

Background Art

[0002] Patent Document 1 below discloses a hot water supply system including a plurality of heat pump units capable of changing the heating capacity by varying the operating frequency of a compressor, a calculation unit that calculates the heating capacity per unit required to achieve a target stored hot water volume at a target time, and a drive unit that drives the heat pump units with the heating capacity calculated by this calculation unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is known a hot water supply system that receives a DR (Demand Response) implementation request regarding adjustment of power consumption transmitted from an electric power company or an aggregator and controls the boiling operation according to the DR implementation request. DR includes up-DR and down-DR. Up-DR means increasing the power demand during a specific time period, and down-DR means decreasing the power demand during a specific time period. If the hot water supply system performs a boiling operation at maximum capacity when down-DR ends and power becomes available, there is a risk of generating a power peak.

[0005] The present disclosure has been made to solve the above-described problems. An object of the present disclosure is to provide a hot water supply system that is advantageous in preventing the occurrence of a power peak immediately after the end of down-DR.

Means for Solving the Problems

[0006] The hot water supply system according to the present disclosure includes a hot water storage tank, a plurality of heat source machines connected to the hot water storage tank, control means for controlling the operation of the plurality of heat source machines, and communication means capable of receiving an instruction for suppressing power consumption. During a predetermined time after the end of the power consumption suppression instruction, a predetermined ratio of the required heating capacity is evenly distributed to the number of heat source machines selected from the plurality of heat source machines, thereby setting the target heating capacity per heat source machine and performing a boiling-up operation.

Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a hot water supply system that is advantageous in preventing a power peak from occurring immediately after the end of the down DR.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described with reference to the drawings. The same reference numerals are given to common or corresponding elements in each figure, and the description will be simplified or omitted. The configurations shown in the following embodiments are examples of the technical idea according to the present disclosure, and can be combined with other known technologies, or a plurality of technical ideas described in the present disclosure can be combined. Further, within the scope not departing from the gist of the present disclosure, a part of the configuration can be omitted or changed.

[0010] Embodiment 1. FIG. 1 is a diagram showing a hot water supply system according to Embodiment 1. As shown in FIG. 1, the hot water supply system 1 of the present embodiment includes one tank unit 5 incorporating a hot water storage tank 2 and a plurality of heat source machines 3 connected to the hot water storage tank 2 in one tank unit 5. The heat source machine 3 may be a heat pump type including a compressor that compresses a refrigerant, a water-cooled refrigerant heat exchanger that performs heat exchange between the refrigerant and water, an expansion device that expands the refrigerant, and an air heat exchanger that absorbs heat of the outside air into the refrigerant.

[0011] The plurality of heat source machines 3 are connected in parallel to one hot water storage tank 2. That is, each heat source machine 3 is connected to the hot water storage tank 2 via a forward pipe that sends hot water from the hot water storage tank 2 to the heat source machine 3 and a return pipe that returns the hot water that has exited the heat source machine 3 to the hot water storage tank 2. In the example of FIG. 1, the number of connected heat source machines 3 is four, but the number of connected heat source machines 3 is not limited to this, and may be three or less or five or more.

[0012] The tank unit 5 is connected to a hot water supply destination 100 via a hot water supply pipe 101. The hot water stored in the hot water storage tank 2 is sent to the hot water supply destination 100 through the hot water supply pipe 101.

[0013] A control device 4 for controlling the operation of the hot water supply system 1 is installed in the tank unit 5. FIG. 2 is a functional block diagram of the hot water supply system 1 according to Embodiment 1. As shown in FIG. 2, each heat source machine 3 is connected to the control device 4. The control device 4 includes a control means 6 and a communication means 7. The control means 6 controls the operation of the plurality of heat source machines 3. The communication means 7 can receive an instruction for suppressing power consumption. The control device 4 and the control device mounted on the heat source machine 3 may be configured to cooperate to control the operation of the heat source machine 3.

[0014] A plurality of hot water storage temperature sensors 8 are installed at different height positions in the hot water storage tank 2. According to these hot water storage temperature sensors 8, the amount of heat stored and the amount of hot water stored in the hot water storage tank 2 can be detected.

[0015] The hot water supply system 1 is capable of performing a heating-up operation. In the heating-up operation, the hot water sent from the hot water storage tank 2 is heated by the heat source machine 3, and the hot water heated by the heat source machine 3 is made to flow into the hot water storage tank 2. In the hot water supply system 1, the number of heat source machines 3 to be operated during the heating-up operation can be changed.

[0016] The heating capacity [kW] is the amount of heat given to water per unit time during the heating-up operation. The heat source machine 3 may be configured to be able to change the heating capacity by changing the rotational speed of the compressor.

[0017] The communication means 7 can receive a demand response (hereinafter also referred to as "DR") implementation request from an aggregator or an electric power company to control the energy resources on the customer side and change the power demand pattern. There are an upward DR and a downward DR in DR. The upward DR means increasing the power demand amount in a specific time zone, and the downward DR means decreasing the power demand amount in a specific time zone.

[0018] When the communication means 7 receives a downward DR implementation request, the control means 6 controls so as not to perform the heating-up operation within the designated downward DR period. The downward DR implementation request corresponds to an instruction to suppress power consumption.

[0019] After the end of the downward DR period, the control device 4 sets the target heating capacity per heat source machine 3 by equally distributing a predetermined ratio of the required heating capacity to the number of heat source machines 3 selected from the plurality of heat source machines 3 for a predetermined time, and performs the heating-up operation. The predetermined ratio is a value smaller than 100%. The predetermined ratio may be, for example, 50%. The predetermined time may be, for example, 1 hour.

[0020] In the present embodiment, during a predetermined time after the end of the reduction DR period, since the boiling-up operation is performed with a heating capacity smaller than the required heating capacity, the power consumption of the hot water supply system 1 can be suppressed. Therefore, it is possible to prevent the occurrence of a power peak and prevent the power supply-demand balance from being disrupted. Further, instead of operating at the maximum capacity of a single heat source machine 3, a plurality of heat source machines 3 are operated at a low capacity. Therefore, the operation of each heat source machine has a high COP, and even when the same heating capacity is obtained as a whole, the power consumption can be reduced, and it is possible to avoid the occurrence of a power peak immediately after the reduction DR.

[0021] The hot water supply system 1 may operate all the heat source machines 3 during a predetermined time after the end of the reduction DR period. By operating all the heat source machines 3, each heat source machine 3 operates at a low capacity. Therefore, the operation of each heat source machine has a high COP, and even when the same heating capacity is obtained as a whole, the power consumption can be reduced, and it is possible to avoid the occurrence of a power peak immediately after the reduction DR.

[0022] FIG. 3 is a flowchart showing the control operation in Embodiment 1. As step S1 in FIG. 3, the control device 4 determines whether or not it is necessary to perform the boiling-up operation after the end of the reduction DR. If it is necessary to perform the boiling-up operation, the process proceeds to step S2. If it is not necessary to perform the boiling-up operation, the processing of the flowchart ends.

[0023] In step S2, the control device 4 calculates the required heating capacity Qall [kW] of the entire hot water supply system 1 by the following equation. Qall=(Mt-M) / (Tt-T) However, Mt [kJ] is the required hot water storage amount, M [kJ] is the current hot water storage amount, Tt [s] is the time to secure the required hot water storage amount, and T [s] is the current time.

[0024] Subsequently, as step S3, the control device 4 calculates the heating capacity Q [kW] of each heat source machine 3 by the following equation. Q=Qall / N×α However, N[-] is the number of the heat source machines 3 to be operated, and α[-] is the capacity reduction ratio. α is a value corresponding to the above-mentioned predetermined ratio and is a value such that 0 < α < 1.

[0025] Subsequently, as step S4, the control device 4 determines whether a predetermined time has elapsed since the end of the lowering DR period. When the predetermined time has elapsed since the end of the lowering DR period, the control device 4 changes the heating capacity Q [kW] of each heat source machine 3 as follows. Q = Qall / N

[0026] That is, when the predetermined time has elapsed since the end of the lowering DR period, the control device 4 determines the heating capacity of each heat source machine 3 by equally distributing the required heating capacity to the heat source machines 3 of the number of units to be operated.

[0027] During the period from the end of the lowering DR period to the predetermined time, the control device 4 may adjust the number of operating units of the heat source machine 3 so that the heat source machine 3 has a heating capacity for operating at the maximum efficiency. For example, when the heating capacity when the heat source machine 3 operates at the maximum efficiency is Qm, the number of operating units of the heat source machine 3 may be calculated by Qall / Qm. As a result, since each heat source machine 3 operates at the maximum efficiency, the COP of the operation of each unit becomes high, and even when the same heating capacity is obtained as a whole, the power consumption can be reduced, and it is possible to avoid the occurrence of a power peak immediately after the lowering DR.

[0028] During the period from the end of the lowering DR period to the predetermined time, a plurality of heat source machines 3 selected in order from the heat source machines 3 with less accumulated operation time may be operated. Thereby, since the operation time of each heat source machine 3 can be averaged, it is possible to prevent the possibility of failure of a specific heat source machine 3 from increasing.

[0029] The boiling temperature is the temperature of the hot water flowing out of the heat source machine 3. The heat source machine 3 is provided with a boiling temperature sensor and can detect the boiling temperature.

[0030] For a predetermined time period from the end of the lowering DR period, a plurality of heat source units 3 sequentially selected from the heat source units 3 with less cumulative operation time and a low average value of the operation time of the boiling temperature may be operated. That is, the heat source unit 3 selected from the higher rank obtained by summing the rank in ascending order of the cumulative operation time and the rank in ascending order of the average value of the operation time of the boiling temperature may be operated. The higher the boiling temperature, the higher the load on the heat source unit 3. Therefore, by sequentially selecting from the heat source units 3 with less cumulative operation time and a low average value of the operation time of the boiling temperature, the heat source unit 3 with a low load can be preferentially selected, and the load of each heat source unit 3 can be averaged. Therefore, it is possible to prevent the possibility of failure of a specific heat source unit 3 from increasing.

[0031] FIG. 4 is a diagram showing an example of a configuration for realizing the functions of the control device 4 in the first embodiment. Each function of the control device 4 is realized by, for example, a processing circuit. The processing circuit may be dedicated hardware 600. The processing circuit may include a processor 601 and a memory 602. A part of the processing circuit may be formed as dedicated hardware 600, and the processing circuit may further include a processor 601 and a memory 602. In the example shown in FIG. 4, a part of the processing circuit is formed as dedicated hardware 600. Also, in the example shown in FIG. 4, the processing circuit further includes a processor 601 and a memory 602 in addition to the dedicated hardware 600.

[0032] Examples of the processing circuit, a part of which is at least one piece of dedicated hardware 600, include a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

[0033] When the processing circuit includes at least one processor 601 and at least one memory 602, the functions of each part of the control device 4 are realized by software, firmware, or a combination of software and firmware.

[0034] Software and firmware are described as programs and stored in the memory 602. The programs may be recorded on a computer-readable recording medium. The processor 601 realizes the functions of each part by reading and executing the programs stored in the memory 602. The processor 601 is also referred to as a CPU (Central Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a DSP. The memory 602 includes, for example, non-volatile or volatile semiconductor memories such as RAM, ROM, flash memory, EPROM, and EEPROM, or magnetic disks, flexible disks, optical disks, compact disks, mini-disks, and DVDs.

[0035] In this way, the processing circuit can realize the functions of the control device 4 by hardware, software, firmware, or a combination thereof. Note that each function of the control device 4 may be realized by a plurality of devices cooperating with each other or by a single device. Also, at least a part of each function of the control device 4 may be implemented in a server or the like on an external network. Hereinafter, various aspects of the present disclosure will be collectively described as appendices.

[0036] (Appendix 1) A hot water storage tank, A plurality of heat source machines connected to the hot water storage tank, Control means for controlling the operation of the plurality of heat source machines, Communication means capable of receiving a power consumption suppression instruction, Comprising, A hot water supply system that performs a boiling operation by setting the target heating capacity per heat source machine by equally distributing a predetermined ratio of the required heating capacity to the number of heat source machines selected from the plurality of heat source machines during a predetermined time after the end of the power consumption suppression instruction. (Appendix 2) The hot water supply system according to Supplementary Note 1, wherein after the elapse of the predetermined time, the target heating capacity per heat source machine is set by equally distributing the required heating capacity to all the heat source machines, and a boiling-up operation is performed. (Supplementary Note 3) The hot water supply system according to Supplementary Note 1 or Supplementary Note 2, wherein during the predetermined time, the number of operating heat source machines is adjusted so that the heating capacity of the heat source machines is such that they operate with maximum efficiency. (Supplementary Note 4) The hot water supply system according to any one of Supplementary Notes 1 to 3, wherein during the predetermined time, a plurality of the heat source machines are sequentially selected from the heat source machines with less accumulated operation time and operated. (Supplementary Note 5) The hot water supply system according to any one of Supplementary Notes 1 to 3, wherein during the predetermined time, a plurality of the heat source machines are sequentially selected from the heat source machines with less accumulated operation time and a low average operation time of the boiling-up temperature and operated. (Supplementary Note 6) The hot water supply system according to Supplementary Note 1 or Supplementary Note 2, wherein during the predetermined time, all the heat source machines are operated.

Explanation of Signs

[0037] 1 Hot water supply system, 2 Hot water storage tank, 3 Heat source machine, 4 Control device, 5 Tank unit, 6 Control means, 7 Communication means, 8 Hot water storage temperature sensor, 100 Hot water supply destination, 101 Hot water supply pipe, 600 Dedicated hardware, 601 Processor, 602 Memory

Claims

1. A hot water storage tank, a plurality of heat source machines connected to the hot water storage tank, control means for controlling the operation of the plurality of heat source machines, communication means capable of receiving a power consumption suppression instruction, and comprising: A hot water supply system that performs a boiling-up operation by setting the target heating capacity per heat source machine by equally distributing a predetermined ratio of the required heating capacity to the number of heat source machines selected from the plurality of heat source machines for a predetermined time after the end of the power consumption suppression instruction.

2. The hot water supply system according to claim 1, wherein after the elapse of the predetermined time, the target heating capacity per heat source machine is set by equally distributing the required heating capacity to all the heat source machines, and a boiling-up operation is performed.

3. The hot water supply system according to claim 1 or claim 2, wherein during the predetermined time, the number of operating heat source machines is adjusted so that the heat source machines have a heating capacity for operating at maximum efficiency.

4. The hot water supply system according to claim 1 or claim 2, wherein during the predetermined time, a plurality of the heat source machines are sequentially selected from the heat source machines with less accumulated operation time and operated.

5. The hot water supply system according to claim 1 or claim 2, wherein during the predetermined time, a plurality of the heat source machines are sequentially selected from the heat source machines with less accumulated operation time and a low average operation time value of the boiling-up temperature and operated.

6. The hot water supply system according to claim 1 or claim 2, wherein during the predetermined time, all the heat source machines are operated.

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