Heat pump hot water system

Abstract

To provide a heat pump hot water supply system capable of executing a hot water storage operation while reducing use of commercial power supply even without means to detect surplus power.SOLUTION: A heat pump hot water supply system (1) is equipped with a heat pump type heat source machine (10), a hot water storage tank (21), and control means (29) for controlling a hot water storage operation for storing, in the hot water storage tank (21), hot water heated by the heat pump type heat source machine (10) using power supplied from a photovoltaic power generation device and commercial power supply, and has a saving mode for saving power consumption in the hot water storage operation. A surplus power time zone in which an occurrence of surplus power by a photovoltaic power generation device is predicted is set beforehand. When storing hot water for the required heat quantity in the saving mode, the control means (29) sets minimum output of the output of the heat pump type heat source machine (10) that can be set so that the hot water storage operation is completed within the surplus power time zone, as output of the heat pump type heat source machine (10), and executes the hot water storage operation.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a heat pump hot water supply system equipped with a heat pump type heat source unit and a hot water storage tank, and in particular to a heat pump hot water supply system that performs hot water storage operation by using electricity supplied from a solar power generation device and a commercial power source to store hot water heated by the heat pump type heat source unit in the hot water storage tank. [Background technology]

[0002] Conventionally, heat pump hot water supply systems have been widely used, which perform a hot water storage operation to store hot water heated by a heat pump heat source in a hot water storage tank, and use the hot water stored in the hot water storage tank for hot water supply. The heat pump hot water supply system predicts, for example, future hot water usage times and hot water usage amounts based on the past hot water usage history, calculates the required heat amount equivalent to the hot water usage amount, and stores the required heat amount until the predicted hot water usage time.

[0003] A heat pump type heat source machine consumes electricity when it heats hot water using heat from outside air. Electricity is generally supplied from a commercial power source, but if a solar power generation device is installed, the electricity generated by the solar power generation device is consumed by the machine itself, and any shortfall is supplied from the commercial power source. Meanwhile, surplus electricity that is not consumed by the machine itself is sold or stored in a power storage device. For example, Patent Document 1 describes a technology that predicts surplus electricity from solar power generation and performs hot water storage operation when there is sufficient surplus electricity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6630631 Summary of the Invention [Problem to be solved by the invention]

[0005] If surplus power from a solar power generation system can be used for hot water storage operation to reduce the power supply from a commercial power source, as in Patent Document 1, the energy costs of a heat pump hot water supply system can be reduced.

[0006] However, a heat pump hot water supply system that does not have a means for detecting surplus power cannot control the hot water storage operation according to the surplus power, and therefore the power consumption of the hot water storage operation may exceed the surplus power. Also, if a means for detecting surplus power is provided, the manufacturing cost of the heat pump hot water supply system increases, which is not preferable.

[0007] An object of the present invention is to provide a heat pump hot water supply system that can perform hot water storage operation while reducing power consumption from a commercial power source even without a means for detecting surplus power. [Means for solving the problem]

[0008] The heat pump hot water supply system of the invention of claim 1 comprises a heat pump type heat source unit, a hot water storage tank, and a control means for controlling a hot water storage operation in which hot water heated by the heat pump type heat source unit is stored in the hot water storage tank using power supplied from a solar power generation device and a commercial power source, the heat pump hot water supply system having a saving mode for saving power consumption in the hot water storage operation, a surplus power time period in which the generation of surplus power by the solar power generation device is predicted is set in advance, and when the required amount of heat is stored in the saving mode, the control means: Based on the surplus power time period, The hot water storage operation is completed within the surplus power time period. Maximum hot water storage operation time setting and can be set so that the storage of the required amount of heat is completed within the maximum hot water storage operation time. Of the output of the heat pump type heat source machine, The power consumption is the lowest The heat pump type heat source unit is characterized in that the hot water storage operation is performed by setting a minimum output as the output of the heat pump type heat source unit.

[0009] According to the above configuration, in the hot water storage operation in the saving mode, during the surplus power time period in which the generation of surplus power is predicted, The maximum hot water storage operation time can be set so that hot water storage operation can be completed, and the required amount of hot water storage can be completed within the maximum hot water storage operation time. Of the heat pump heat source unit's output, The power consumption is the lowest The minimum output is set and hot water is stored. Therefore, surplus electricity is used to perform hot water storage operation, During surplus power hours The storage of the required amount of heat can be completed. Since the power consumption during the hot water storage operation is small, the number of cases where the surplus power is exceeded is reduced, and the power supply from the commercial power source can be reduced, thereby reducing energy costs. In addition, since there is no need for a means to detect surplus power, the increase in manufacturing costs for the heat pump hot water supply system can be suppressed.

[0010] The heat pump hot water supply system of the invention of claim 2 is characterized in that, in the invention of claim 1, the hot water storage operation is performed by setting the hot water storage temperature that requires the smallest power consumption among the hot water storage temperatures at which the hot water storage operation is completed within the surplus power time period. According to the above configuration, it is possible to complete the storage of the required amount of hot water, and to further reduce the power consumption during the hot water storage operation, thereby reducing the power supply from the commercial power source. Effect of the Invention

[0011] According to the heat pump hot water supply system of the present invention, it is possible to reduce the power consumption of the commercial power source and perform hot water storage operation even without a means for detecting surplus power. [Brief description of the drawings]

[0012] [Figure 1] 1 is an explanatory diagram of the peripheral configuration of a heat pump hot water supply system according to an embodiment of the present invention. [Diagram 2] 1 is an explanatory diagram of a heat pump hot water supply system according to an embodiment. [Diagram 3] FIG. 2 is an explanatory diagram of a main heat source unit according to an embodiment. [Figure 4] 11 is a flowchart of hot water storage operation control in a saving mode according to an embodiment. [Diagram 5] 13 is a power consumption table for hot water storage operation in a saving mode according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the mode for carrying out the present invention will be described based on examples. EXAMPLES

[0014] First, the peripheral configuration of the heat pump hot water supply system 1 will be described with reference to FIG. The heat pump hot water supply system 1 has a heat pump type heat source unit as a main heat source unit 10, a hot water storage unit 20, and an auxiliary heat source unit 40. This heat pump hot water supply system 1 is connected to a distribution board 2 via a power line 1a. The distribution board 2 distributes power supplied from a commercial power line 3 connected to a commercial power source and generated power supplied from a solar power generation device 4 to the heat pump hot water supply system 1 and devices that use power (not shown).

[0015] The solar power generation device 4 has a junction box 6 for combining DC power generated by the solar panels 5 when they receive sunlight, and a power conditioner 7 connected to convert the DC power combined in the junction box 6 into AC power (generated power). The generated power supplied from the solar power generation device 4 is consumed by the device itself, and surplus power that is not consumed by the device itself is sold via a commercial power line 3 connected from the distribution board 2 to a commercial power source. The surplus power may be stored in a power storage device (not shown).

[0016] The heat pump hot water supply system 1 is driven by using either the generated power or commercial power supplied from the distribution board 2, either alone or in combination. The power supplied to the heat pump hot water supply system 1 is supplied to the hot water storage unit 20 via power line 1a, and is supplied from the hot water storage unit 20 to the main heat source unit 10 and the auxiliary heat source unit 40 via power lines 10a, 40a. Note that the auxiliary heat source unit 40 may be supplied with power directly from the distribution board 2.

[0017] The heat pump hot water supply system 1 will be described with reference to FIG. The heat pump hot water supply system 1 is configured to perform a hot water storage operation in which hot water heated by the main heat source unit 10 is stored in the hot water storage tank 21 of the hot water storage unit 20. The hot water stored in the hot water storage tank 21 is supplied to, for example, the hot water tap 8 via the auxiliary heat source unit 40. The auxiliary heat source unit 40 is, for example, a combustion type heat source unit, and supplies the hot water supplied from the hot water storage unit 20 to the hot water tap 8 with or without reheating.

[0018] A main heat source unit forward passage 23 equipped with a pump 22 is connected to the bottom of the hot water storage tank 21 in order to supply hot water from the hot water storage tank 21 to the main heat source unit 10. A main heat source unit return passage 24 is connected to the top of the hot water storage tank 21 in order to supply hot water heated by the main heat source unit 10 to the hot water storage tank 21. A changeover valve 25 for switching the hot water flow path is provided in the middle of the main heat source unit return passage 24, and a return branch passage 24a branched off from the main heat source unit return passage 24 by the changeover valve 25 is connected to a portion of the main heat source unit forward passage 23 upstream of the pump 22.

[0019] A return temperature sensor 24b that detects the temperature of the hot water heated by the main heat source unit 10 is disposed upstream of the switching valve 25 in the main heat source unit return passage 24. For example, if the temperature detected by the return temperature sensor 24b immediately after the main heat source unit 10 is started up is low, the switching valve 25 is switched from the hot water tank 21 side to the return branch passage 24a side, and the hot water is circulated without being returned to the hot water tank 21 until it can be sufficiently heated.

[0020] A water supply passage 26 that supplies clean water, as indicated by arrow CW, is connected to the bottom of hot water storage tank 21. A hot water outlet passage 27 that outputs hot water from hot water storage tank 21 to the outside of hot water storage unit 20 is connected to the top of hot water storage tank 21. A water supply branch passage 26a that branches off from the middle of water supply passage 26 is connected to a mixing valve 28 that is disposed midway on hot water outlet passage 27. A plurality of hot water temperature sensors 21a to 21d are disposed in hot water storage tank 21, and can detect the temperature of the hot water stored in hot water storage tank 21 and the amount of hot water stored therein.

[0021] A supply water temperature sensor 26b is disposed in the water supply passage 26 to detect the temperature (supply water temperature) of clean water supplied from the water supply passage 26. A hot water outlet passage 27 is disposed in the hot water outlet flow rate sensor 27a to detect the hot water outlet flow rate from the hot water storage unit 20, a hot water storage tank outlet temperature sensor 27b to detect the temperature of hot water discharged from the hot water storage tank 21 (hot water storage tank outlet temperature), and an outlet hot water temperature sensor 27c to detect the outlet hot water temperature from the hot water storage unit 20.

[0022] The hot water outlet passage 27 of the hot water storage unit 20 and the water supply port 40a of the auxiliary heat source unit 40 are connected by a hot water passage 31. The hot water supply port 40b of the auxiliary heat source unit 40 is connected to a hot water supply passage 32 connected to a hot water tap 8. The hot water discharged from the hot water storage unit 20 is supplied to the hot water tap 8 via the auxiliary heat source unit 40, and is supplied from the hot water tap 8 as shown by the arrow HW.

[0023] The hot water storage unit 20 has a control unit 29 (control means) that controls the hot water storage operation. The control unit 29 drives the pump 22 to circulate hot water between the hot water storage tank 21 and the main heat source unit 10, and stores the hot water heated by the main heat source unit 10 from the upper part of the hot water storage tank 21. The control unit 29 also adjusts the mixing ratio in the mixing valve 28 based on the hot water storage tank outlet temperature, the water supply temperature, and the hot water outlet flow rate, and supplies hot water so that the temperature detected by the outlet hot water temperature sensor 27c becomes, for example, a preset hot water supply setting temperature or a predetermined temperature. The predetermined temperature is set so that the auxiliary heat source unit 40 can heat the hot water supplied from the hot water storage unit 20 to the hot water supply setting temperature and supply hot water.

[0024] An operation terminal 30 that allows a user to set, for example, a hot water supply temperature setting is connected to the control unit 29. This operation terminal 30 is also connected to an auxiliary heat source unit 40, and is configured to be able to supply hot water at the hot water supply temperature setting set by the operation terminal 30 to the hot water tap 8.

[0025] 3, the main heat source unit 10 has a heat pump circuit in which a compressor 11, a condensing heat exchanger 12, an expansion valve 13, and an evaporative heat exchanger 14 are connected by a refrigerant passage 15, a blower 16 for blowing air to the evaporative heat exchanger 14, and an outside air temperature sensor 17. In hot water storage operation, the refrigerant filled in the heat pump circuit of the main heat source unit 10 is circulated, and the refrigerant compressed by the compressor 11 and raised in temperature heats hot water supplied from the hot water storage tank 21 through heat exchange in the condensing heat exchanger 12.

[0026] The refrigerant, whose temperature has been reduced by the heat exchange, undergoes adiabatic expansion in the expansion valve 13 and becomes colder than the outside air. This low-temperature refrigerant is heated in the evaporation heat exchanger 14 by heat exchange with the outside air blown by the blower 16. The heated refrigerant is introduced back into the compressor 11.

[0027] The control unit 29 predicts the future hot water usage time and hot water usage amount based on, for example, the stored past hot water usage history, and calculates the required heat amount corresponding to the hot water usage amount. Then, the control unit 29 controls the hot water storage operation so that the storage of the required heat amount is completed by the predicted hot water usage time.

[0028] The control unit 29 has a normal mode and a saving mode as modes for performing hot water storage operation. The normal mode is a mode in which hot water is stored by setting the heating capacity (output) and hot water storage temperature of the main heat source unit 10 so as to increase the operating efficiency based on the hot water supply setting temperature, the water supply temperature, and the outside air temperature. The saving mode is a mode in which hot water is stored by setting the output and hot water storage temperature of the main heat source unit 10 so as to save power consumption in the hot water storage operation. In either mode, the hot water storage temperature is set higher than the hot water supply setting temperature, and the lower the hot water storage temperature, the higher the operating efficiency of the hot water storage operation and the lower the power consumption. Also, the lower the output of the main heat source unit 10, the lower the power consumption in the hot water storage operation.

[0029] When a user of the heat pump hot water supply system 1 that can use the power generated by the solar power generation device 4 wishes to reduce the energy cost of hot water storage operation, the user can switch from normal mode to saving mode by operating the operation terminal 30. In saving mode, the minimum output of the main heat source unit 10 that can be set so that the hot water storage operation is completed by the predicted hot water supply usage time and within the surplus power time period in which the solar power generation device 4 is predicted to generate surplus power is set as the output of the main heat source unit 10. Since the generation situation of surplus power differs depending on the installation environment of the solar power generation device 4 and the lifestyle of the user, the surplus power time period is set in advance by the user operating the operation terminal 30.

[0030] Next, the control of the hot water storage operation in the saving mode by the control unit 29 will be described based on the flowchart of Fig. 4 and with reference to the power consumption table of the hot water storage operation in Fig. 5. In the figure, Si (i = 1, 2, ...) represents a step.

[0031] First, in S1, the maximum hot water storage operation time in the saving mode is set based on the predicted hot water usage time and the surplus power time zone, and then the process proceeds to S2. For example, if the current time is 13:00, the predicted hot water usage time is 17:00, and the surplus power time zone is set to 9:00 to 16:00, in order to complete hot water storage by the predicted hot water usage time and within the surplus power time zone, the maximum hot water storage operation time is set to 180 minutes so that hot water storage is completed at the earlier time of 16:00.

[0032] In S2, it is determined whether the required heat quantity is equal to or less than the maximum heat quantity that can be stored in hot water storage tank 21. The maximum heat quantity is determined by the hot water storage temperature and the capacity of hot water storage tank 21, and here, the maximum heat quantity is set to 6500 [kcal] when the hot water storage temperature is 65 [°C]. Since it is not possible to store an amount of heat that exceeds the maximum heat quantity during hot water storage operation, the shortfall is made up by auxiliary heat source unit 40 during hot water supply. If the determination in S2 is Yes (the required heat quantity is equal to or less than the maximum heat quantity), the process proceeds to S3, and if the determination in S2 is No (the required heat quantity exceeds the maximum heat quantity), the process proceeds to S6.

[0033] In S3, the output of the main heat source unit 10 is set based on the required heat amount and the maximum hot water storage operation time set in S1, and the process proceeds to S4. For example, when the required heat amount is 5200 [kcal], the output required to complete hot water storage within the maximum hot water storage operation time (within 180 minutes) is calculated to be 28.9 [kcal / min] or more. Then, as a settable output that is greater than the calculated required output, for example, of outputs of 30, 40, and 50 [kcal / min], the minimum output of 30 [kcal / min] that minimizes power consumption is set as the output of the main heat source unit 10 (see FIG. 5).

[0034] In S4, the hot water storage temperature is set based on the required heat quantity, and the process proceeds to S5. For example, the hot water supply setting temperature is set to 42[°C], and the settable hot water storage temperatures are 45, 50, 55, 60, and 65[°C]. The amount of heat generated when hot water storage tank 21 is filled with hot water at the settable hot water storage temperatures is equal to or greater than the required heat quantity of 5200[kcal], and among the hot water storage temperatures of 55, 60, and 65[°C] at which the required heat quantity can be stored, 55[°C], the lowest temperature at which power consumption during hot water storage operation is minimized, is set as the hot water storage temperature (see FIG. 5).

[0035] The power consumption in S3 and S4 above is calculated by the control unit 29 according to the output of the main heat source unit 10 and the hot water temperature, based on the supply water temperature and the outside air temperature. Note that the control unit 29 may store a plurality of power consumption tables in which the power consumption is calculated according to the output and the hot water temperature by changing the supply water temperature and the outside air temperature.

[0036] In S5, hot water storage operation is performed at the hot water storage temperature set in S4 with the output of the main heat source unit 10 set in S3, and when storage of the required amount of heat is completed, control of the hot water storage operation is terminated.

[0037] On the other hand, if the determination in S2 is No, in S6, the output of the main heat source unit 10 is set based on the maximum hot water storage heat amount and the maximum hot water storage operation time, and the process proceeds to S7. For example, when the required heat amount is 7000 [kcal], the output required to complete hot water storage of the maximum hot water storage heat amount of 6500 [kcal] within the maximum hot water storage operation time is calculated to be 36.1 [kcal / min] or more. Among the settable outputs of, for example, 40 and 50 [kcal / min] as outputs that are greater than the required output, the minimum output of 40 [kcal / min] that minimizes power consumption is set as the output of the main heat source unit 10 (see FIG. 5). The power consumption in S6 may also be calculated by the control unit 29 according to the output of the main heat source unit 10 and the hot water storage temperature based on the water supply temperature and the outdoor air temperature, as described above, or a plurality of power consumption tables calculated in advance may be stored in the control unit 29.

[0038] Next, in S7, the hot water storage temperature is set to the maximum temperature, and the process proceeds to S5. For example, if the settable hot water storage temperatures are 45, 50, 55, 60, and 65°C, the hot water storage temperature is set to 65°C, which is the maximum temperature at which the maximum amount of hot water heat can be stored. Then, in S5, hot water storage operation is performed at the hot water storage temperature set in S7 with the output of the main heat source unit 10 set in S6, and when the maximum amount of hot water heat has been stored, the control of the hot water storage operation is terminated.

[0039] The operation and effects of the heat pump hot water supply system 1 will be described. In the hot water storage operation in the saving mode, the minimum output of the main heat source unit 10 that can store the required amount of heat during the surplus power time period when the generation of surplus power is predicted is set and hot water is stored. Therefore, the hot water storage operation is performed using the surplus power, and the storage of the required amount of heat can be completed. Furthermore, since the power consumption in the hot water storage operation is small, there are fewer cases where the surplus power is exceeded, and the power supply from the commercial power source can be reduced, thereby reducing energy costs. In addition, since there is no need for a means for detecting surplus power, the increase in manufacturing costs of the heat pump hot water supply system 1 can be suppressed.

[0040] In addition, the hot water storage temperature that requires the least amount of power consumption is set among the hot water storage temperatures at which the hot water storage operation is completed within the surplus power time period, and the hot water storage operation is performed by setting the temperature at which the least amount of power consumption is required. This allows the storage of the required amount of heat to be completed within the surplus power time period, and further reduces the power consumption of the hot water storage operation, thereby reducing the power supply from the commercial power source.

[0041] The heat pump hot water supply system 1 may be configured such that an auxiliary heat source unit 40 is built into the hot water storage unit 20, and hot water in the hot water storage tank 21 from the hot water storage unit 20 is adjusted in temperature, or hot water heated by the auxiliary heat source unit 40 is adjusted in temperature, and hot water is supplied to the hot water tap 8. Furthermore, the settable output and settable hot water storage temperature of the main heat source unit 10 described above are merely examples for the purpose of explanation, and are not limited to the above.

[0042] In addition, a person skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiment without departing from the spirit of the present invention, and the present invention includes such modifications. [Explanation of symbols]

[0043] 1: Heat pump hot water system 2: Distribution board 3: Commercial power line 4: Solar power generation equipment 5: Solar panel 6: Junction box 7: Power conditioner 8: Hot water tap 10: Main heat source unit (heat pump type heat source unit) 11: Compressor 12: Condensing heat exchanger 13: Expansion valve 14: Evaporative heat exchanger 15: Refrigerant passage 16: Blower 17: Outside air temperature sensor 20: Hot water storage unit 21: Hot water tank 21a to 21d: Hot water temperature sensor 22: Pump 23: Heat source machine access passage 24: Heat source return passage 24a: Return passage 24b: Return temperature sensor 25: Switching valve 26:Water supply passage 26a: Water supply branch passage 26b: Water supply temperature sensor 27: Hot water passage 27a: Flow rate sensor 27b: Hot water tank outlet temperature sensor 27c: Outlet water temperature sensor 28: Mixing valve 29: Control unit (control means) 30: Operation terminal 31:Hot water passage 32: Hot water passage 40:Auxiliary heat source machine

Claims

1. A heat pump hot water supply system including a heat pump type heat source device, a hot water storage tank, and a control means for controlling a hot water storage operation in which hot water heated by the heat pump type heat source device is stored in the hot water storage tank using power supplied from a solar power generation device and a commercial power source, A saving mode for saving power consumption in the hot water storage operation is provided, A surplus power time period during which the generation of surplus power by the solar power generation device is predicted is set in advance; the control means, when storing the required amount of heat in the saving mode, sets a maximum hot water storage operation time based on the surplus power time zone so that the hot water storage operation is completed within the surplus power time zone; A heat pump hot water supply system characterized in that the hot water storage operation is performed by setting the output of the heat pump type heat source unit to the minimum output that minimizes power consumption among the outputs of the heat pump type heat source unit that can be set so that the storage of the required amount of heat is completed within the maximum hot water storage operation time.

2. The heat pump hot water supply system according to claim 1, characterized in that the hot water storage operation is performed by setting the hot water storage temperature at which the power consumption is the smallest among the hot water storage temperatures at which the hot water storage operation is completed within the surplus power time period.

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