JP5899344B2 - Heat pump system - Google Patents

Description

  The present invention relates to a heat pump system.

  Patent Document 1 discloses a heat pump system including a heat pump unit including a heat pump that absorbs heat from outside air and heats the heat medium, and a tank unit including a tank that stores the heat medium. In this heat pump system, in order to prevent the heat medium from freezing, it is possible to perform an antifreeze operation in which heating is performed while circulating the heat medium between the tank and the heat pump. In this heat pump system, the heat medium is heated by the heat pump in the freeze prevention operation.

JP 2009-156495 A

  In general, since heating of the heat medium by the heat pump is high in energy efficiency, it is preferable to heat the heat medium to prevent freezing by driving the heat pump. In addition, in a system having only a heat pump as a heat source, even when the outside air temperature is low, not only for anti-freezing operation but also when it is necessary to store heat in the tank, for example, when hot water for hot water supply needs to be stored It is necessary to drive the heat pump. However, when the heat pump is driven in a situation where the outside air temperature is low, there is a possibility that the evaporator that performs heat exchange between the refrigerant of the heat pump and the outside air may be frosted. If the evaporator is frosted, drainage is generated along with the defrosting operation, so that a separate measure for preventing the drain from freezing is required. In particular, in a system having only a heat pump as a heating source, a defrosting operation is always required, so that a drain freezing prevention measure is also necessarily required. For this reason, it is preferable that the evaporator of the heat pump is not frosted as much as possible.

  The present specification provides a technique for solving the above problems. The present specification provides a technology capable of preventing a situation in which a heat pump heated by a heat pump accumulates in a tank, and prevents a frost from forming on the evaporator of the heat pump due to the freeze prevention operation.

The heat pump system disclosed in the present specification includes a heat pump unit including a heat pump that absorbs heat from outside air and heats the heat medium, a tank unit including a tank that stores the heat medium, and a heat medium supplied from the tank to the heat medium utilization point. An auxiliary heat source unit for heating the battery is provided. The heat pump system further includes an outside air temperature detecting means for detecting the outside air temperature, and a heater provided in a flow path through which the heat medium flows between the tank and the heat pump. In order to prevent the heat medium from freezing, the heat pump system can execute an anti-freezing operation in which the heat medium is heated while circulating the heat medium between the tank and the heat pump. In the anti-freezing operation, the heat pump system heats the heat medium with a heat pump when the outside air temperature is high, and heats the heat medium with a heater when the outside air temperature is low.

  In the above heat pump system, the heating means used in the freeze prevention operation is switched according to the outside air temperature. When the outside air temperature is high, energy efficiency can be increased by heating the heat medium with a heat pump. Further, when the outside air temperature is low, frosting on the evaporator of the heat pump can be prevented by heating the heat medium with a heater and not heating the heat medium with a heat pump. According to the above heat pump system, it is possible to prevent a situation where the evaporator of the heat pump is frosted due to the freeze prevention operation. Note that the heat pump system described above can heat the heat medium using the auxiliary heat source unit even when the heat pump unit is not driven when the outside air temperature is low, for example, to produce and supply hot water for hot water supply. As a result, convenience is not impaired. Any auxiliary heat source unit may be used as long as it is a heat source that does not form frost upon driving, such as a gas heat source unit, a gas engine cogeneration unit, a fuel cell, or a heater.

  The above heat pump system can be configured such that a heater is provided in a flow path inside the tank unit.

  According to the above heat pump system, the detection value of the thermistor (the thermistor for detecting the temperature of the heat medium or the thermistor for detecting the temperature of the refrigerant circulating in the heat pump) in the heat pump unit is affected by the heat radiation from the heater. Can be prevented.

  The above heat pump system can be configured such that a heater is provided in the flow path where the heat medium returns from the heat pump to the tank.

  In general, the flow path for sending the heat medium from the tank to the heat pump is more likely to freeze the heat medium than the flow path for returning the heat medium from the heat pump to the tank. For this reason, the necessity of the freeze prevention operation is often determined based on the temperature of the heat medium detected in the flow path for sending the heat medium from the tank to the heat pump. According to the above heat pump system, since the heater is provided in the flow path for returning the heat medium from the heat pump to the tank, the detection value of the thermistor provided in the flow path for sending the heat medium from the tank to the heat pump is from the heater. It can be prevented from being affected by heat dissipation.

  According to the heat pump system disclosed in the present specification, it is possible to prevent a situation where the evaporator of the heat pump is frosted due to the freeze prevention operation.

It is a figure which shows typically the structure of the hot water supply system 10 of an Example. It is a flowchart explaining the freeze prevention operation which the hot water supply system 10 of an Example performs. It is a figure which shows typically the structure of the modification of the hot water supply system 10 of an Example.

(Example)
FIG. 1 shows a configuration of a hot water supply system 10 of the present embodiment. As shown in FIG. 1, the hot water supply system 10 includes a hot water storage unit 20, an HP heat source unit 40, a gas heat source unit 50, and a controller 11.

  The HP heat source unit 40 includes a compressor 41, a first heat exchanger 43 that is a condenser, an expansion valve 44, and a heat pump 40a that includes a second heat exchanger 45 that is an evaporator. In the heat pump 40a, the discharge side of the compressor 41, the four-way valve 42, the refrigerant flow path 43a of the first heat exchanger 43, the expansion valve 44, the second heat exchanger 45, the four-way valve 42, and the suction side of the compressor 41 are refrigerant. The pipes 46 are connected in order, and the refrigerant circulates in this order. The refrigerant may be, for example, R744 (CO2 refrigerant) or R410A (HFC refrigerant). The first heat exchanger 43 includes a refrigerant channel 43a and a circulating water channel 43b. A fan 45 a is installed in the vicinity of the second heat exchanger 45. The second heat exchanger 45 performs heat exchange between the outside air sent by the fan 45a and the refrigerant. A defrosting path 47 is connected to the refrigerant pipe 46 between the discharge side of the compressor 41 and the four-way valve 42, and between the expansion valve 44 and the second heat exchanger 45. In the defrosting path 47, a defrosting valve 47a is provided.

  A circulation forward path connection path 48 is connected to the inlet side of the circulating water flow path 43b of the first heat exchanger 43, and a circulation return path connection path 49 is connected to the outlet side. The circulation path connection path 48 is provided with an inlet side thermistor 48a, and the circulation path connection path 49 is provided with an outlet side thermistor 49a. The inlet side thermistor 48a detects the temperature of the circulating water flowing into the circulating water flow path 43b of the first heat exchanger 43, and the outlet side thermistor 49a is the circulating water flowing out of the circulating water flow path 43b of the first heat exchanger 43. Detect the temperature. Actually, each thermistor 48a, 49a outputs a detection signal corresponding to the water temperature, and this signal is input to the controller 11 to detect the water temperature. In the following description, the expression that a thermistor or sensor detects actually means that the temperature or the flow rate of water is detected by inputting these detection signals to the controller 11.

  The hot water storage unit 20 includes a hot water storage tank 21 and a mixer 24. A water supply path 22 for supplying tap water to the hot water tank 21 is connected to the bottom of the hot water tank 21. In the vicinity of the tap water inlet 22 a of the water supply path 22, a pressure reducing valve 23 is provided. The pressure reducing valve 23 adjusts the water supply pressure to the water supply path 22. A mixed water supply path 26 of the mixer 24 is connected to the downstream side of the pressure reducing valve 23 of the water supply path 22. In the mixed water supply path 26, a water supply control valve 26a, a water supply flow rate sensor 26b, and a water supply thermistor 26c are provided. The water supply control valve 26 a adjusts the flow rate of tap water flowing through the mixed water supply path 26. The water supply flow rate sensor 26 b and the water supply thermistor 26 c detect the flow rate and temperature of tap water flowing through the mixed water supply path 26. When the hot water in the hot water storage tank 21 decreases or the water supply control valve 26a opens, the downstream pressure of the pressure reducing valve 23 decreases. The pressure reducing valve 23 opens when the downstream pressure decreases, and tries to maintain the pressure at a predetermined pressure regulation value. For this reason, when the hot water in the hot water storage tank 21 decreases or the water supply control valve 26a of the mixer 24 is opened, tap water is supplied thereto.

  In the water supply path 22, a drainage path 31 is connected to the downstream side of the connection portion of the mixed water supply path 26. A drain valve 32 is provided in the middle of the drain path 31. The drain valve 32 can be manually opened and closed. When the drain valve 32 is opened, the water in the hot water tank 21 is drained to the outside through the drain path 31.

  One end of a circulation outward path 33 is connected to the bottom of the hot water tank 21, and one end of a circulation return path 34 is connected to the upper part of the hot water tank 21. The other end of the circulation outward path 33 is connected to the circulation outward path connection path 48 of the HP heat source unit 40, and the other end of the circulation return path 34 is connected to the circulation return path connection path 49. A circulation thermistor 36 and a circulation pump 37 are provided in the circulation outward path 33. The outward thermistor 36 detects the temperature of the water that has flowed out of the hot water storage tank 21 into the circulation outward path 33. When the circulation pump 37 is driven, water is sucked out from the lower part of the hot water storage tank 21 to the circulation outward path 33, and this water flows through the circulating water flow path 43 b of the first heat exchanger 43 and passes through the circulation return path 34 to the upper part of the hot water storage tank 21. Returned. In this way, a circulation path between the hot water tank 21 and the heat pump 40a is configured.

  An electric freezing prevention heater 34 a is provided in the circulation return path 34 inside the tank unit 20. A pressure release path 38 is connected in the middle of the circulation return path 34, and a relief valve 38 a is provided in the pressure release path 38. The valve opening pressure of the relief valve 38 a is set slightly higher than the pressure regulation value of the pressure reducing valve 23. When the pressure regulation of the pressure reducing valve 23 becomes impossible, the relief valve 38a is opened to prevent the pressure in the hot water storage tank 21 from exceeding the pressure that can withstand pressure. In the hot water storage tank 21, an upper thermistor 39 is attached to a predetermined amount (for example, 30 liters) from the upper end. The upper thermistor 39 detects the water temperature at the upper part of the hot water tank 21. The hot water storage unit 20 is also provided with an outside air temperature thermistor 35 that detects the outside air temperature.

  A hot water path 25 of the mixer 24 is connected to the upper part of the hot water tank 21. The warm water path 25 is provided with a warm water control valve 25a, a warm water flow rate sensor 25b, and a warm water thermistor 25c. The hot water control valve 25 a adjusts the flow rate of water flowing from the hot water tank 21 to the hot water path 25. The hot water flow rate sensor 25 b detects the flow rate of water flowing from the hot water storage tank 21 to the hot water path 25. The hot water thermistor 25 c detects the temperature of the water flowing through the hot water path 25. The warm water path 25 and the mixed water supply path 26 merge and are connected to the first mixing path 27. The first mixing path 27 is provided with a mixing thermistor 27 a that detects the temperature of the mixed water flowing through the first mixing path 27.

  The hot water storage unit 20 includes a first hot water supply path 29. A hot water supply thermistor 29 a is provided in the first hot water supply path 29. A hot-water tap 60 is connected to the tip of the first hot water supply path 29. The hot-water tap 60 is arranged in a bathroom, a washroom, a kitchen, etc. (in FIG. 1, the plurality of hot-water taps 60 are represented by one). The middle of the first mixing path 27 and the middle of the first hot water supply path 29 are connected by a hot water supply bypass path 28. The hot water supply bypass path 28 is provided with a bypass control valve 28a. When the bypass control valve 28a is opened, the mixed water flowing through the first mixing path 27 flows to the hot water supply bypass path 28, and when the bypass control valve 28a is closed, the mixed water flowing through the first mixing path 27 is It flows to the second mixing path 51 of the gas heat source unit 50 described later.

  The gas heat source unit 50 includes a burner heat exchanger 52, a burner 53, and the like. The mixed water from the first mixing path 27 of the hot water storage unit 20 flows into the burner heat exchanger 52 through the second mixing path 51. The second mixing path 51 is provided with an incoming water thermistor 51a, a hot water supply flow rate sensor 51b, and a water amount servo 51c. The incoming water thermistor 51a and the hot water supply flow rate sensor 51b detect the temperature and flow rate of the water flowing through the second mixing path 51, respectively. The water amount servo 51 c adjusts the flow rate of water flowing through the second mixing path 51. The gas combustion type burner 53 heats the burner heat exchanger 52. The water heated by the burner heat exchanger 52 flows into the first hot water supply path 29 of the hot water storage unit 20 through the second hot water supply path 54. In the second hot water supply path 54, a can body thermistor 55 is provided near the outlet of the burner heat exchanger 52, and a hot water thermistor 56 is provided downstream thereof. A heat source bypass path 57 is connected between the downstream side of the water amount servo 51 c in the second mixing path 51 and the can body thermistor 55 and the hot water thermistor 56 in the second hot water supply path 54. A heat source unit bypass control valve 58 is provided at a connection portion between the second mixing path 51 and the heat source unit bypass path 57. By adjusting the opening degree of the heat source unit bypass control valve 58, a part of the water flowing through the second mixing path 51 flows into the heat source unit bypass path 57, and the flow rate of the water is adjusted.

  The controller 11 includes a CPU, a ROM, a RAM, and the like. Various operation programs are stored in the ROM. The RAM temporarily stores various signals input to the controller 11 and various data generated in the course of execution of processing by the CPU. Specifically, the detection signals of the various thermistors 25c, 26c, 27a, 29a, 35, 36, 39, 48a, 49a, 51a, 55, 56 and the flow sensors 25b, 26b, 51b are input to the RAM. These pieces of information are temporarily stored. In the controller 11, the CPU outputs drive signals to various devices such as the hot water storage unit 20, the HP heat source unit 40, and the gas heat source unit 50 based on information stored in the ROM and RAM. A remote controller 13 is connected to the controller 11. The remote controller 13 is provided with a switch 16 for operating the hot water supply system 10, a liquid crystal display 17 for displaying an operation state of the hot water supply system 10, and the like, and information set by the remote controller 13 is input to the controller 11. .

(Heat storage operation)
In the hot water supply system 10, it is possible to execute a heat storage operation in which the water in the hot water storage tank 21 is heated by the heat pump 40 a to be hot hot water, and the hot water is stored in the hot water storage tank 21.

  In the heat storage operation, the compressor 41 is driven in the HP heat source unit 40. When the refrigerant compressed by the compressor 41 flows through the refrigerant channel 43a of the first heat exchanger 43, the circulating water flowing through the circulating water channel 43b is heated. The refrigerant that has flowed out of the refrigerant flow path 43a is expanded and cooled by the expansion valve 44, and when it flows through the second heat exchanger 45, it absorbs heat from the outside air and rises in temperature. The temperature of the refrigerant that has been raised flows into the compressor 41 and is compressed again, so that the temperature is further raised.

  In the hot water storage unit 20, the circulation pump 37 is operated, and the water in the hot water storage tank 21 is sucked out from the bottom of the hot water storage tank 21 to the circulation forward path 33. The water sucked into the circulation outward path 33 is heated and increases in temperature when passing through the circulation water flow path 43b of the first heat exchanger 43 of the HP heat source unit 40. The hot water whose temperature has risen flows through the circulation return path 34 and is returned to the upper part of the hot water tank 21. By this circulation, the hot water storage tank 21 forms a temperature stratification in which the high temperature layer is laminated on the upper side of the low temperature layer. As hot hot water continues to be returned to the hot water tank 21, the thickness (depth) of the high temperature layer gradually increases, and when hot water is stored to the maximum, hot water is stored in the entire hot water tank 21. Become. When the temperature stratification is formed in the hot water storage tank 21, even if the hot water storage tank 21 does not store heat to the maximum extent, hot hot water can be sent out to the hot water path 25 connected to the upper part of the hot water storage tank 21. It becomes possible.

(Hot water operation)
In the hot water supply operation, the mixed water adjusted to the hot water supply set temperature by the mixer 24 was adjusted to a temperature lower than the hot water supply set temperature by the first hot water supply operation for supplying hot water from the hot water tap 60 through the hot water supply bypass path 28. One of the 2nd hot water supply operation which heats mixed water with gas heat source unit 50, and supplies hot water from hot-water tap 60 is performed.

  When the detected water temperature of the upper thermistor 39 of the hot water tank 21 is equal to or higher than the first reference temperature (for example, the hot water set temperature + 5 ° C.) higher than the hot water set temperature set by the remote controller 13, the first hot water operation is performed. Is called. In the first hot water supply operation, the controller 11 opens the bypass control valve 28a and fully closes the water amount servo 51c. The controller 11 adjusts the opening degree of the hot water control valve 25a and the opening degree of the water supply control valve 26a so that the water temperature detected by the mixing thermistor 27a becomes the hot water supply set temperature. The mixed water adjusted to the hot water supply set temperature flows through the first mixing path 27, and then hot water is supplied from the hot water tap 60 through the hot water supply bypass path 28 and the first hot water supply path 29.

  On the other hand, when the detected water temperature of the upper thermistor 39 is lower than the first reference temperature, the second hot water supply operation is performed. In the second hot water supply operation, the controller 11 fully closes the bypass control valve 28a and sets the water amount servo 51c to a predetermined opening. The controller 11 adjusts the opening degree of the hot water control valve 25a and the water supply control valve 26a so that the water temperature detected by the mixed thermistor 27a becomes a second reference temperature lower than the hot water supply set temperature (for example, the hot water supply set temperature −5 ° C.). Adjust the opening. The mixed water adjusted to the second reference temperature flows through the first mixing path 27, flows through the second mixing path 51 of the gas heat source unit 50, flows into the burner heat exchanger 52, and is heated by the burner 53. The heating capacity of the burner 53 is controlled so that the water temperature detected by the can body thermistor 55 provided at the outlet of the burner heat exchanger 52 is 60 ° C. or higher. Thereby, it can suppress that dew condensation water generate | occur | produces in piping. A part of the mixed water flowing through the second mixing path 51 flows into the second hot water supply path 54 through the heat source unit bypass path 57, and water of 60 ° C. or higher from the burner heat exchanger 52 and the second from the heat source unit bypass path 57. The water at the reference temperature is mixed, and the water at the hot water supply set temperature is sent to the first hot water supply path 29. In this way, the water adjusted to the hot water supply set temperature is supplied from the hot water tap 60 through the first hot water supply path 29. Thereby, even when the hot water stored in the hot water storage tank 21 is completely consumed during the first hot water supply operation, the hot water adjusted to the hot water supply set temperature can be continuously supplied.

(Defrosting operation)
When the heat pump 40a is driven in a state where the outside air temperature is low such as in winter, the second heat exchanger 45 may be frosted. If the second heat exchanger 45 is frosted, the efficiency of heat exchange with the outside air is lowered, and the heating capacity of the circulating water in the heat pump 40a is lowered. Therefore, in the hot water supply system 10 of the present embodiment, when the second heat exchanger 45 is frosted, a defrosting operation for defrosting from the second heat exchanger 45 can be performed. In the defrosting operation, in the HP heat source unit 40, the compressor 41 is driven with the defrosting valve 47a opened. As a result, the high-temperature refrigerant discharged from the compressor 41 flows to the second heat exchanger 45 through the defrosting path 47 and circulates back to the compressor 41 as indicated by broken line arrows in FIG. When the high-temperature refrigerant flows through the second heat exchanger 45, it can be defrosted from the second heat exchanger 45.

(Anti-freezing operation)
When a long time elapses without performing the heat storage operation in a state where the outside air temperature is low such as in winter, the circulating water flow path 43b of the first heat exchanger 43, the circulation outward path 33, the circulation outbound path connection path 48, and the circulation return path connection path 49 Circulating water may stay inside the circulation return path 34, and the circulating water may freeze inside these pipes. If the circulating water is frozen, the heat storage operation cannot be executed until the frozen circulating water is melted. Therefore, in the hot water supply system 10 of this embodiment, when the outside air temperature is low and the temperature of the circulating water is lowered, it is possible to perform an antifreezing operation that prevents the circulating water from freezing. Hereinafter, the freeze prevention operation performed by the hot water supply system 10 will be described with reference to FIG.

  In step S202, it is determined whether or not the temperature of the circulating water is below a predetermined temperature (for example, 10 ° C.). In the following description, the temperature of the circulating water refers to the temperature of the circulating water in the circulating outbound path 33 detected by the outbound thermistor 36 and the circulating water in the circulating outbound connection path 48 detected by the inlet-side thermistor 48a. It means the lower one of the temperatures. If the temperature of the circulating water is equal to or higher than the predetermined temperature (NO in step S202), the process returns to step S202. When the temperature of the circulating water is lower than the predetermined temperature (YES in step S202), the process proceeds to step S204.

  In step S204, it is determined whether or not the outside air temperature detected by the outside air temperature thermistor 35 is lower than a predetermined temperature (for example, 5 ° C.). If the outside air temperature is equal to or higher than the predetermined temperature (NO in step S204), the process returns to step S202. If the outside air temperature falls below the predetermined temperature (YES in step S204), the process proceeds to step S206.

  In step S206, the circulation pump 37 is driven. Thereby, the circulating water is sucked out from the lower part of the hot water storage tank 21, and the circulation outward path 33, the circulation outbound path connection path 48, the circulation water path 43 b of the first heat exchanger 43, the circulation return path connection path 49, and the circulation return path 34 are sequentially arranged. Via, the circulating water is returned to the upper part of the hot water tank 21. The circulating water inside the circulation outward path 33, the circulation outbound path connection path 48, the circulation water flow path 43b of the first heat exchanger 43, the circulation return path connection path 49, and the circulation return path 34 is replaced by the flow of the circulating water.

  In step S208, the temperature of the circulating water (the temperature of the circulating water in the circulating outbound path 33 detected by the outbound path thermistor 36 and the temperature of the circulating water in the circulating outbound path connection path 48 detected by the inlet-side thermistor 48a is low. It is determined whether or not the temperature is higher than a predetermined temperature (for example, 13 ° C.). If residual heat remains in the hot water storage tank 21 when the freeze prevention operation is started in step S206, the circulation pump 37 is driven to circulate the circulation outward path 33, the circulation outward path connection path 48, and the first heat exchanger 43. Circulating water inside the water flow path 43 b, the circulation return path connection path 49, and the circulation return path 34 is replaced with warm circulating water from the hot water storage tank 21. In this case, there is no need to continue the freeze prevention operation. Accordingly, when the temperature of the circulating water becomes equal to or higher than the predetermined temperature in step S208 (YES), the process proceeds to step S228, the circulation pump 37 is stopped, and the freeze prevention operation is ended. If the temperature of the circulating water is less than the predetermined temperature in step S208 (in the case of NO), the process proceeds to step S210.

  In step S210, it is determined whether or not the outside air temperature is equal to or higher than a predetermined temperature (for example, 6 ° C.). If the outside air temperature rises to a temperature at which the circulating water is not likely to freeze after starting the freeze prevention operation in step S206, it is not necessary to continue the freeze prevention operation any further. Accordingly, when the outside air temperature becomes equal to or higher than the predetermined temperature in step S210 (YES), the process proceeds to step S228, the circulation pump 37 is stopped, and the freeze prevention operation is ended. If the outside air temperature is less than the predetermined temperature in step S210 (NO), the process proceeds to step S212.

  In step S212, it is determined whether or not a predetermined time (for example, 30 minutes) has elapsed since the circulation pump 37 was driven in step S206. If the predetermined time has not elapsed (NO in step S212), the process returns to step S208. If the predetermined time has elapsed (YES in step S212), the process proceeds to step S214. The process proceeds from step S212 to step S214 when the temperature of the circulating water does not reach the predetermined temperature (that is, no residual heat remains in the hot water storage tank 21) until a predetermined time has elapsed after the circulation pump 37 is driven. And the outside air temperature does not rise. In such a case, in the hot water supply system 10 of the present embodiment, the circulating water is heated in the processing after step S214.

  In step S214, it is determined whether or not the outside air temperature is lower than a predetermined temperature (for example, −10 ° C.). In general, since the heating of the circulating water by the heat pump 40a is high in energy efficiency, it is preferable to heat the circulating water to prevent freezing by driving the heat pump 40a. However, if heating by the heat pump 40a is performed in a state where the outside air temperature is low, the second heat exchanger 45 may be frosted. If the second heat exchanger 45 is frosted, drainage is generated along with the defrosting operation, and therefore a separate measure for preventing the drain from freezing is required. For this reason, it is preferable that the second heat exchanger 45 is not frosted as much as possible. Therefore, in the hot water supply system 10 of the present embodiment, when the circulating water is heated in the freeze prevention operation, the heating means is switched according to the outside air temperature.

  If the outside air temperature is equal to or higher than the predetermined temperature in step S214 (NO), the process proceeds to step S216. In step S216, the compressor 41 is driven and heating of the circulating water by the heat pump 40a is started. In step S218, the temperature of the circulating water (the temperature of the circulating water in the circulating outbound path 33 detected by the outbound thermistor 36 and the temperature of the circulating water in the circulating outbound path 48 detected by the inlet-side thermistor 48a is low). Waits until the temperature of the one reaches a predetermined temperature (for example, 30 ° C.) or higher. If the temperature of circulating water becomes more than predetermined temperature by step S218 (it becomes YES), the compressor 41 will be stopped by step S220 and the heating of circulating water by the heat pump 40a will be complete | finished. Thereafter, the process proceeds to step S228, the circulation pump 37 is stopped, and the freeze prevention operation is ended.

  If the outside air temperature exceeds the predetermined temperature in step S214 (NO), the process proceeds to step S222. In step S222, the anti-freezing heater 34a is turned on, and heating of the circulating water by the anti-freezing heater 34a is started. In step S224, the process waits until the outside air temperature becomes equal to or higher than a predetermined temperature (for example, −8 ° C.). When the outside air temperature becomes equal to or higher than the predetermined temperature in step S224 (YES), the freeze prevention heater 34a is turned off in step S226, and the heating of the circulating water by the freeze prevention heater 34a is finished. Thereafter, the process proceeds to step S228, the circulation pump 37 is stopped, and the freeze prevention operation is ended.

  As described above, in the hot water supply system 10 of the present embodiment, when the freeze prevention operation is performed, the circulating water is heated by the heat pump 40a when the outside air temperature is high, and by the freeze prevention heater 34a when the outside air temperature is low. Heat the circulating water. By adopting such a configuration, it is possible to prevent a situation where the second heat exchanger 45 of the heat pump 40a is frosted due to the freeze prevention operation.

  In the hot water supply system 10 described above, the antifreeze heater 34 a is provided not in the HP heat source unit 40 but in the hot water storage unit 20. With such a configuration, the detection values of the thermistors in the HP heat source unit 40 (an inlet-side thermistor 48a that detects the temperature of circulating water, an outlet-side thermistor 49a, and a thermistor (not shown) that detects the temperature of the refrigerant) are prevented from freezing. It is possible to prevent the heat radiation from the heater 34a.

  In the hot water supply system 10 described above, not only in the antifreezing operation but also in the heat storage operation, when the outside air temperature is lower than a predetermined temperature (for example, −10 ° C.), the circulating water is not heated by the heat pump 40a. And it is good also as a structure which prevents the frost formation to the 2nd heat exchanger 45. FIG. Even in such a configuration, according to the hot water supply system 10 described above, water at the hot water supply set temperature can be supplied to the hot water tap 60 by the second hot water supply operation using the gas heat source unit 50. The frost formation on the second heat exchanger 45 of the heat pump 40a can be prevented without impairing the convenience for the user.

  In the hot water supply system 10 described above, the freeze prevention heater 34 a is provided not in the circulation outward path 33 but in the circulation return path 34. By adopting such a configuration, it is possible to prevent the detection value of the forward thermistor 36 from being affected by the heat radiation from the antifreezing heater 34a.

  As shown in FIG. 3, even when the anti-freezing heater 34a is provided in the circulation forward path connection path 48 inside the HP heat source unit 40, the anti-freezing operation is performed by performing the anti-freezing operation as shown in FIG. Therefore, it is possible to prevent the second heat exchanger 45 of the heat pump 40a from frosting.

  In the above-described embodiment, the configuration in which tap water (water supply) supplied with hot water is used as the heat medium circulated between the heat pump 40a and the hot water tank 21 has been described. Unlike this, for example, an antifreeze liquid is used as a heat medium circulated between the heat pump 40a and the hot water storage tank 21, and heat is exchanged between tap water (water supply) supplied by hot water supply and the antifreeze liquid stored in the hot water storage tank 21. It is good also as a structure which utilizes the heat storage of the hot water storage tank 21 for hot water supply by providing a heat exchanger separately.

  In the above embodiment, the configuration in which the heat medium stored in the hot water storage tank 21 is used for hot water supply has been described. Unlike this, for example, the heat medium stored in the hot water storage tank 21 may be used for heating such as floor heating or bathroom drying heater. Alternatively, the heat medium stored in the hot water storage tank 21 may be used for both hot water supply and heating.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

DESCRIPTION OF SYMBOLS 10 Hot water supply system 11 Controller 13 Remote control 16 Switch 17 Liquid crystal display 20 Hot water storage unit 21 Hot water storage tank 22 Water supply path 22a Tap water inlet 23 Pressure reducing valve 24 Mixer 25 Hot water path 25a Hot water control valve 25b Hot water flow rate sensor 25c Hot water thermistor 26 Mixed water supply path 26a Water supply control valve 26b Water supply flow sensor 26c Water supply thermistor 27 First mixing path 27a Mixing thermistor 28 Hot water supply bypass path 28a Bypass control valve 29 First hot water supply path 29a Hot water supply thermistor 31 Drainage path 32 Drain valve 33 Circulation forward path 34 Circulation return path 34a Freezing prevention Heater 35 Outside temperature thermistor 36 Outward thermistor 37 Circulation pump 38 Pressure release path 38a Relief valve 39 Upper thermistor 40 HP heat source unit 40a Heat pump 41 Compressor 42 Four-way valve 43 First heat exchanger 3a Refrigerant flow path 43b Circulating water flow path 44 Expansion valve 45 Second heat exchanger 45a Fan 46 Refrigerant pipe 47 Defrost path 47a Defrost valve 48 Circulation forward path connection path 48a Inlet side thermistor 49 Circulation return path connection path 49a Outlet side thermistor 50 Gas Heat source unit 51 Second mixing path 51a Incoming thermistor 51b Hot water flow sensor 51c Water quantity servo 52 Burner heat exchanger 53 Burner 54 Second hot water path 55 Can body thermistor 56 Hot water thermistor 57 Heat source machine bypass path 58 Heat source machine bypass control valve 60 Hot water tap

Claims (3)

A heat pump unit including a heat pump that absorbs heat from outside air and heats the heat medium;
A tank unit having a tank for storing a heat medium;
A heat pump system including an auxiliary heat source unit that heats a heat medium supplied from a tank to a heat medium utilization location ,
Outside temperature detecting means for detecting outside temperature;
A heater provided in a flow path through which the heat medium flows between the tank and the heat pump;
In order to prevent the heat medium from freezing, it is possible to perform an anti-freezing operation in which heating is performed while circulating the heat medium between the tank and the heat pump.
In a freeze prevention operation, a heat pump system that heats a heat medium with a heat pump when the outside air temperature is high, and heats the heat medium with a heater when the outside air temperature is low.   The heat pump system according to claim 1, wherein a heater is provided in a flow path inside the tank unit.   The heat pump system according to claim 2, wherein a heater is provided in a flow path where the heat medium returns from the heat pump to the tank.

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