JP5378504B2 - Heat pump water heater - Google Patents

Description

  The present invention provides a liquid-refrigerant heat exchanger using a heat pump circuit in which a compressor, a liquid-refrigerant heat exchanger (including a water-refrigerant heat exchanger), an expansion valve, and an evaporator are connected by a refrigerant pipe. The present invention relates to a heat pump type water heater for boiling liquid (including water).

  2. Description of the Related Art A heat pump type hot water heater having a boiling function for driving a heat pump circuit using midnight power or the like and heating low temperature water to store hot water at a desired temperature in a hot water storage tank is known. When such a heat pump water heater is operated under conditions such as a low outside air temperature, moisture in the outside air freezes on the evaporator and forms frost, thereby reducing the performance of the evaporator. For this reason, defrosting operation of an evaporator is implemented and defrosting is performed.

  When carrying out the defrosting operation, in order to improve the efficiency of the defrosting operation, it is proposed to stop the circulation pump that circulates the water in the hot water storage tank through the water-refrigerant heat exchanger of the heat pump circuit ( For example, Patent Document 1). In this way, the amount of heat absorbed by the water in the water-refrigerant heat exchanger when the refrigerant circulating in the heat pump circuit passes through the water-refrigerant heat exchanger can be reduced, so that the heat of the refrigerant is evaporated. It can be used effectively for defrosting in a vessel.

  Further, in order to improve the efficiency of the defrosting operation, the defrosting preparation operation for reducing the flow rate of the circulation pump that circulates the water in the hot water storage tank through the water-refrigerant heat exchanger of the heat pump circuit is performed prior to the defrosting operation. Has been proposed (for example, Patent Document 2).

  However, in the invention described in Patent Document 2, since the circulation pump is driven at a low flow rate during the defrost preparation operation, low-temperature water in the hot water storage tank is introduced into the water-refrigerant heat exchanger. Therefore, there is a problem that the heat of the refrigerant circulating in the heat pump circuit is absorbed by the water in the water-refrigerant heat exchanger when passing through the water-refrigerant heat exchanger.

  Therefore, a bypass pipe is provided to flow the water derived from the water-refrigerant heat exchanger bypassing the hot water storage tank, and the water derived from the water-refrigerant heat exchanger is circulated through the bypass pipe during the defrost preparation operation. It has been proposed to stop the circulation pump during the defrosting operation (for example, Patent Document 3).

Japanese Patent No. 3297657 JP 2008-39360 A JP 2008-121923 A JP 2004-37011 A JP 2007-333340 A JP-A-5-272812 JP 2003-222391 A

  However, since the heat pump type water heater described in Patent Document 3 is for stopping the circulation pump during the defrosting operation, the heat pump type water heater is operated in an environment where the outside air temperature is extremely low such as −15 ° C. or lower. In such a case, there is a risk that the freezing in the circulation pipe may occur and the subsequent boiling operation becomes difficult or impossible.

  Therefore, the present invention has an object to provide a heat pump type water heater that can perform a stable boiling operation by preventing freezing of water in a pipe even when the outside air condition is operated in a cryogenic environment. And

  A heat pump hot water supply apparatus according to the present invention includes a compressor that compresses a refrigerant, a liquid-refrigerant heat exchanger that heats a liquid stored in a storage tank by a high-temperature, high-pressure refrigerant discharged from the compressor, An evaporator for exchanging heat between the low-temperature and low-pressure refrigerant flowing from the liquid-refrigerant heat exchanger through the expansion valve with air, a storage tank for storing the liquid heated by the liquid-refrigerant heat exchanger, A forward pipe for sending liquid to the liquid-refrigerant heat exchanger; and a return pipe for returning the liquid heated by the liquid-refrigerant heat exchanger to the storage tank, and heating the low-temperature liquid to the storage tank. A bypass pipe connecting the forward pipe and the return pipe so that the liquid flowing out from the liquid-refrigerant heat exchanger bypasses the storage tank, and the liquid-refrigerant heat exchanger Liquid spilled from A heat pump type that includes a path switching mechanism that switches between a path that is sent to the storage tank and a path that bypasses the storage tank, and performs a defrosting operation that introduces a high-temperature refrigerant into the evaporator and melts frost adhering to the evaporator In the water heater, a high-temperature liquid introduction operation is performed to introduce a liquid higher in temperature than the low-temperature liquid into the liquid-refrigerant heat exchanger before the defrosting operation, and from the liquid-refrigerant heat exchanger during the defrosting operation. A bypass circulation operation is performed in which the liquid that has flowed out is circulated through the bypass pipe at a lower flow rate than in the boiling operation.

  According to the heat pump type water heater having the above configuration, since hot water is introduced into the liquid-refrigerant heat exchanger even during the defrosting operation, it is possible to prevent freezing in the piping during the defrosting operation. In addition, the temperature of the refrigerant can be prevented from decreasing in the liquid-refrigerant heat exchanger, and the heat of the refrigerant can be effectively used for defrosting in the evaporator, thereby improving the efficiency of the defrosting operation. it can.

  The heat pump water heater further includes an outside air temperature detection unit that detects an outside air temperature, and performs the high-temperature liquid introduction operation when the temperature detected by the outside air temperature detection unit becomes a predetermined temperature or less. preferable. In this way, when the outside air temperature is such that the pipe does not freeze even if the high temperature liquid introduction operation is not performed, the high temperature liquid introduction operation is not performed and the outside air temperature at which the pipe may be frozen By performing the high temperature liquid introduction operation only in this case, it is possible to suitably prevent the energy efficiency from being unnecessarily lowered.

  Moreover, it is preferable that the said heat pump type water heater switches the said path | route switching mechanism so that the liquid which flowed out of the said liquid-refrigerant heat exchanger may become a path | route which bypasses a storage tank at the time of the start of the said high temperature liquid introduction operation | movement.

  The heat pump type water heater further includes an inflow liquid temperature detection unit that detects the temperature of the liquid flowing into the liquid-refrigerant heat exchanger, and the high temperature liquid introduction operation is performed at a temperature detected by the inflow liquid temperature detection unit. It is preferable that the process is terminated when either the temperature reaches a predetermined temperature or the predetermined time has passed. If it does in this way, warm water can be reliably introduced into a liquid-refrigerant heat exchanger.

  By the way, depending on the outside air temperature, freezing in the pipe as described above may occur even during defrosting operation (for example, during normal boiling operation). In this case, the boiling operation becomes difficult. There is a risk of problems such as becoming impossible. In that respect, freezing can be prevented by performing the high-temperature liquid introducing operation as described above.

  That is, a heat pump type hot water heater according to the present invention includes a compressor that compresses a refrigerant, a liquid-refrigerant heat exchanger that heats a liquid stored in a storage tank by a high-temperature and high-pressure refrigerant discharged from the compressor, and An evaporator for exchanging heat with low-temperature, low-pressure refrigerant flowing from the liquid-refrigerant heat exchanger through an expansion valve, and a storage tank for storing liquid heated by the liquid-refrigerant heat exchanger; A forward pipe for sending a low-temperature liquid to the liquid-refrigerant heat exchanger; and a return pipe for returning the liquid heated by the liquid-refrigerant heat exchanger to the storage tank, and heating the low-temperature liquid to A bypass pipe that performs a boiling operation for storing in a storage tank, further connects the forward pipe and the return pipe by bypassing the storage tank, and a path through which the liquid flowing out from the liquid-refrigerant heat exchanger is sent to the storage tank And storage In the heat pump water heater, comprising: a path switching mechanism that switches between a path that bypasses the tank and an inflow liquid temperature detection section that detects the temperature of the liquid flowing into the liquid-refrigerant heat exchanger; When the detected temperature is below a predetermined temperature for a predetermined time, the path switching mechanism is switched so that the liquid flowing out from the liquid-refrigerant heat exchanger becomes a path bypassing the storage tank, A liquid higher in temperature than the low-temperature liquid is introduced into the liquid-refrigerant heat exchanger, and the liquid flowing out from the liquid-refrigerant heat exchanger is circulated through the bypass pipe at a lower flow rate than in the boiling operation. The anti-freezing operation is performed to prevent freezing of the outgoing piping toward the liquid-refrigerant heat exchanger.

  The heat pump type hot water heater according to the present invention includes a compressor that compresses a refrigerant, and a liquid-refrigerant heat exchanger that heats a liquid stored in a storage tank by a high-temperature and high-pressure refrigerant discharged from the compressor. An evaporator for exchanging heat between the low-temperature and low-pressure refrigerant flowing from the liquid-refrigerant heat exchanger via an expansion valve with air, an outgoing pipe for sending a low-temperature liquid to the liquid-refrigerant heat exchanger, A return pipe for returning the liquid heated by the liquid-refrigerant heat exchanger to the storage tank, heating the low-temperature liquid and storing it in the storage tank, and further performing the liquid-refrigerant heat exchange A bypass pipe connecting the forward pipe and the return pipe so that the liquid flowing out from the vessel bypasses the storage tank, and a path through which the liquid flowing out from the liquid-refrigerant heat exchanger is sent to the storage tank and the storage tank. A heat pump type hot water heater having a path switching mechanism for switching between the path to be switched and the path switching mechanism to switch the path switching mechanism so that the liquid flowing out of the liquid-refrigerant heat exchanger bypasses the storage tank; A high-temperature liquid introduction operation for introducing a high-temperature liquid into the liquid-refrigerant heat exchanger, a high-temperature refrigerant introduction operation for introducing a high-temperature refrigerant into the evaporator, and the liquid-refrigerant. A bypass circulation operation is performed in which the liquid flowing out of the heat exchanger is circulated through the bypass pipe at a lower flow rate than in the boiling operation.

According to the present invention, it is possible to prevent freezing of water in the pipe during the defrosting operation or the boiling operation even when the outside air condition becomes an extremely low temperature, and a stable boiling operation can be performed. .
Other objects, features and advantages of the present invention will become apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

It is a line | wire system block diagram of the heat pump type hot water heater which concerns on one Embodiment of this invention. It is a flowchart of the defrost operation control of the heat pump type water heater which concerns on one Embodiment of this invention. It is a system | strain block diagram of the heat pump type water heater which concerns on other embodiment of this invention.

  FIG. 1 shows a system configuration diagram of a heat pump type water heater according to an embodiment of the present invention, and FIG. 2 shows a control flow diagram of defrosting operation control which is a characteristic part of the present embodiment.

  As shown in FIG. 1, the heat pump type water heater of the present embodiment has a refrigerant cycle including a liquid-refrigerant heat exchanger (in this embodiment, a water-refrigerant heat exchanger) shown on the left side of the drawing inside the box. A tank unit 2 in which a hot water supply cycle including a mounted heat pump unit 1 and a hot water storage tank 9 as a storage tank shown on the right side of the drawing is mounted inside the box is configured. The heat pump unit 1 and the tank unit 2 are connected to each other using a connection pipe 3 at the construction site of the heat pump type hot water heater. In addition, since the connection piping 3 is selected at the time of construction, the length, the number of bends, and the type of heat insulating material differ depending on the local situation.

  The refrigerant cycle includes a compressor 4 that compresses the refrigerant, and water-refrigerant heat as a liquid-refrigerant heat exchanger that exchanges heat between the high-temperature and high-pressure refrigerant discharged from the compressor 4 and water introduced from the hot water storage tank 9. An exchanger 5, a pressure reducing valve 6 in which the refrigerant flowing out of the water-refrigerant heat exchanger 5 is decompressed, and an evaporator 7 in which the low-temperature and low-pressure refrigerant decompressed by the pressure reducing valve 6 exchanges heat with air. It becomes the structure connected circularly by refrigerant | coolant piping. The evaporator 7 has a structure for exchanging heat with the outside air introduced by the fan 8.

  The water cycle includes a hot water storage tank 9 for storing a predetermined amount of hot water, a circulation pump 10 to which water at the bottom of the hot water storage tank 9 is guided, and a water-refrigerant heat exchanger in which water discharged from the circulation pump 10 exchanges heat with refrigerant. 5 is connected in a ring shape by a circulation pipe. The water discharged from the water-refrigerant heat exchanger 5 is returned to the top of the hot water storage tank 9. Further, a water supply source (not shown) such as a water supply is connected to the bottom of the hot water storage tank 9 via a water supply pipe 11, and a hot water supply pipe 12 for supplying hot water to a place to be used is connected to the top.

  In addition, the heat pump type hot water heater includes a forward pipe 3A for sending a low-temperature liquid (low-temperature water from the bottom of the hot water storage tank 9 in this embodiment) to the water-refrigerant heat exchanger 5, and the water-refrigerant heat exchanger 5 A return pipe 3B is provided for returning the water heated in step 1 to the hot water storage tank 9. The forward piping 3 </ b> A and the return piping 3 </ b> B to the water-refrigerant heat exchanger are configured using the connection piping 3. A bypass pipe 13 is connected to the outgoing pipe 3 </ b> A and the return pipe 3 </ b> B so that water derived from the water-refrigerant heat exchanger 5 bypasses the tank 9.

  In addition, the heat pump type hot water heater is provided with a path switching mechanism that switches between a path through which water derived from the water-refrigerant heat exchanger 5 is sent to the hot water storage tank 9 and a path that bypasses the hot water storage tank 9. Specifically, a switching valve 14 serving as a path switching mechanism that switches the path of water is provided at a connection point between the connection pipe 3 and the bypass pipe 13. The switching valve 14 is provided at a connection point between the outgoing pipe 3 </ b> A to the water-refrigerant heat exchanger and the bypass pipe 13. In addition to the switching valve 14, the path switching mechanism may be constituted by open / close valves provided in the connection pipe 3 and the bypass pipe 13, respectively.

  The bypass pipe 13 is provided in the tank unit 2, and hot water circulates across the heat pump unit 1 and the tank unit 2 during a bypass circulation operation (or hot water circulation operation) described later. With such a configuration, freezing of the outgoing pipe 3A to the liquid-refrigerant heat exchanger that is most likely to be frozen can be suitably prevented. The circulation pump 10 is provided in the heat pump unit 1.

  The heat pump unit 1 is provided with an outside air temperature sensor 15 as an outside air temperature detecting unit that detects the outside air temperature. Specifically, the outside air temperature sensor 15 is provided in the vicinity of the evaporator 7. Further, an evaporator inlet temperature sensor 16 and an evaporator outlet temperature sensor 17 are provided at the refrigerant inlet and outlet, respectively. In the pipes before and after the water-refrigerant heat exchanger 5, an incoming water temperature sensor 18 as an influent temperature sensor for detecting the temperature of the water flowing into the water-refrigerant heat exchanger 5, and the water-refrigerant heat exchanger 5. There is provided a tapping temperature sensor 19 as an effluent temperature detecting section for detecting the temperature of water flowing out of the effluent.

  Next, the defrosting operation control in the heat pump type water heater configured as shown in FIG. 1 will be described in detail with reference to FIG.

  In the boiling operation, the switching valve 14 is set on the hot water storage tank 9 side, and the hot water storage operation is performed in which the hot water heated by the water-refrigerant heat exchanger 5 is stored in the hot water storage tank 9. Further, in the boiling operation, it is determined whether the defrosting operation is necessary, and serves as an inflow refrigerant temperature detection unit that detects the outside air temperature obtained from the outside air temperature sensor 15 and the temperature of the refrigerant flowing into the evaporator. Based on the evaporator inlet temperature obtained from the evaporator inlet temperature sensor 16 and the evaporator outlet temperature obtained from the evaporator outlet temperature sensor 17 serving as a refrigerant outlet temperature sensor for detecting the temperature of the refrigerant flowing out of the evaporator. Determine if frost operation is required. Specifically, the defrosting operation is executed when a predetermined defrosting operation start condition is satisfied. The predetermined defrosting operation start condition is when the evaporator inlet temperature obtained from the evaporator inlet temperature sensor 16 and the evaporator outlet temperature obtained from the evaporator outlet temperature sensor 17 have reached a predetermined temperature.

  When it is determined that the defrosting operation is necessary, it is next determined whether the defrosting preparation operation is necessary. Specifically, it is determined that the defrost preparation operation is necessary when the outside air temperature reaches a predetermined temperature that requires the defrost preparation operation. The predetermined temperature at which the defrost preparation operation is necessary is a temperature (for example, −15 ° C. or less) at which the water in the pipe may be frozen. In the defrost preparation operation, a high-temperature water introduction operation (or a hot water introduction operation) is performed in which water (that is, hot water) that is hotter than cold water (that is, low-temperature water) is introduced into the water-refrigerant heat exchanger 5. Specifically, the switching valve 14 is set on the bypass pipe 13 side while continuing the heat pump operation, and the water in the connection pipe 3 and the bypass pipe 13 is heated by the water-refrigerant heat exchanger 5 to be hot water.

  This defrost preparation operation is performed until a predetermined defrost preparation operation end condition is satisfied. The predetermined defrosting preparatory operation end condition is that the incoming water temperature of the incoming water temperature sensor 18 detected during the defrosting preparatory operation is equal to or higher than a predetermined temperature (for example, 70 ° C.) or predetermined from the start of the defrosting preparatory operation. This is a case where any one of elapses of time (for example, 3 minutes) is satisfied. However, it is not limited to this, either one may be sufficient and other things may be sufficient. For example, it may be based on a change in the temperature of the circulating water, such as when the outlet temperature sensor 19 detected during the defrost preparation operation detects that the temperature of the water has exceeded a predetermined temperature.

  As described above, the defrosting preparation operation time is provided as the defrosting preparation operation end condition in the actual product in which the incoming water temperature reaches a predetermined temperature depending on the length of the connecting pipe 3 and the state of the pipe insulation. This is because there is a possibility that it will not rise, and in this case, an operation different from the defrosting operation that is originally required will be performed for a long time, which is not preferable.

  After completion of the defrost preparation operation, the defrost operation is started. In the defrosting operation, a high-temperature refrigerant introduction operation for introducing a high-temperature refrigerant into the evaporator 7 is performed to melt the frost attached to the evaporator 7. As this method, there are hot gas defrosting that introduces refrigerant discharged from the compressor into the evaporator at a high temperature and reverse cycle defrosting that reverses the heat pump cycle. In the heat pump hot water supply apparatus according to this embodiment, the pressure reducing valve 6, an electromagnetic expansion valve whose opening degree can be adjusted is used, the opening degree of the electromagnetic expansion valve is made larger than that during the boiling operation, and refrigerant having a temperature higher than that during the boiling operation is introduced into the evaporator 7.

  Further, during the defrosting operation, a bypass circulation operation for circulating the water led out from the water-refrigerant heat exchanger 5 through the bypass pipe 13 is performed. Specifically, in the bypass circulation operation, control is performed so that water flows at a predetermined flow rate that is smaller than that in the boiling operation. Specifically, the flow rate during the boiling operation is about 1.0 L / min, whereas the predetermined flow rate of the bypass circulation operation is about 0.1 to 0.2 L / min.

  More specifically, the rotational speed of the circulation pump 10 is set to a predetermined low speed rotational speed. Here, it is desirable that the predetermined low-speed rotation speed is lower than the rotation speed during normal boiling operation and is the rotation speed at which the hot and cold water in the pipe circulates. However, the circulating pump 10 may be driven intermittently (or intermittently) in addition to lowering the rotational speed of the circulating pump 10 than during the boiling operation.

  This defrosting operation is performed until a predetermined defrosting operation end condition is satisfied. Here, depending on the outside air temperature at the place where the heat pump unit 1 is disposed, the evaporator outlet temperature of the evaporator outlet temperature sensor 17 may not rise to a predetermined temperature even though frost has already been removed. In this case, although the frost is removed, the defrosting operation is continued, and a useless operation is performed.

  Therefore, the predetermined defrosting operation end condition is set to satisfy either a predetermined defrosting operation end temperature condition or a predetermined defrosting operation end time condition. However, it is not limited to this, either one may be sufficient and other things may be sufficient. For example, as an example of other defrosting operation termination conditions, the outside air temperature is set to be the same as when the temperature difference between the detected value of the outside air temperature sensor 15 and the detected value of the evaporator inlet temperature sensor 16 is within a predetermined range. The temperature change condition may be taken into consideration.

  First, the predetermined defrosting operation end temperature condition will be described. At least the evaporator outlet temperature of the evaporator outlet temperature sensor 17 is a predetermined temperature (for example, 7 ° C.) or more. Moreover, in order to perform defrosting reliably, the evaporator inlet temperature of the evaporator inlet temperature sensor 16 is also utilized. Specifically, when the evaporator inlet temperature is a predetermined temperature and the evaporator outlet temperature is equal to or higher than a predetermined temperature (for example, 7 ° C.), the defrosting operation end temperature condition is set. However, it is not limited to this, either one may be sufficient and other things may be sufficient. The predetermined defrosting operation end time condition is when a predetermined time (for example, 10 minutes) has elapsed since the start of the defrosting operation.

  When the defrosting operation is completed, the operation proceeds to the boiling operation.

  With the above control, even when the outside air temperature becomes extremely low, the piping during the defrosting operation is filled with hot water, and the hot water is circulated to prevent freezing in the piping. Since it circulates, the defrosting energy is not deprived from the refrigerant flowing through the water-refrigerant heat exchanger 5, so that the influence on the defrosting operation can be suppressed.

  By the way, depending on the outside air temperature, freezing in the pipe as described above may occur even during defrosting operation (for example, during normal boiling operation). In this case, the boiling operation becomes difficult. There is a risk of problems such as becoming impossible. In that respect, freezing can be prevented by performing the warm water introduction operation as described above.

  That is, the heat pump type water heater according to the present embodiment has a predetermined temperature of water entering the water-refrigerant heat exchanger 5 detected by the water temperature sensor 18 as shown in FIG. 2 regardless of the necessity of the defrosting operation. When the temperature is below a predetermined temperature (for example, 3 ° C.) over a period of time (for example, 3 minutes), the freeze prevention operation for forcibly performing the above-described bypass circulation operation is executed.

  Specifically, in the freeze prevention operation, the path switching mechanism is switched so that the water flowing out from the water-refrigerant heat exchanger 5 becomes a path that bypasses the hot water storage tank 9, and water having a temperature higher than that of the low temperature water is supplied. -The water introduced into the refrigerant heat exchanger 5 and flowing out of the water-refrigerant heat exchanger 5 is circulated through the bypass pipe 13 to prevent freezing of the outgoing pipe 3A toward the water-refrigerant heat exchanger 5.

  By performing this freeze prevention operation, it becomes possible to melt the ice even if water in the pipe is frozen during the boiling operation, and it is possible to prevent a problem in the boiling operation due to the pipe freezing.

  And when this freeze prevention operation is performed, the said defrost operation is performed continuously. This is a warm water circulation operation similar to the operation performed in the freeze prevention operation and the defrost preparation operation, and since the hot water is introduced into the water-refrigerant heat exchanger 5 and the bypass pipe 13, the operation proceeds to the defrost operation as it is. Compared to the normal boiling operation, the hot water introduced into the water-refrigerant heat exchanger 5 and the bypass pipe 13 is not wasted, and the evaporator 7 is frosted at this point. Because this frost can be removed, energy efficiency is improved.

  In addition, the heat pump type water heater according to the present invention is not limited to the configuration of the above embodiment, and various modifications can be made without departing from the spirit of the invention.

  For example, in the above embodiment, hot water boiled using the heat pump circuit is stored in the hot water storage tank 9, and hot water is supplied from the hot water storage tank 9 at the hot water supply terminal when hot water is supplied. However, the present invention is not limited to this, for example, hot water supplied at a hot water supply terminal is generated by indirectly heating low temperature water by heat exchange with a high temperature liquid stored in a storage tank. The storage tank may store the liquid heated by the heat pump circuit. In this case, the liquid only needs to function as a heat medium, and may be water or brine. For example, hot water stored in a storage tank is heated by indirectly exchanging low-temperature water with a water-liquid heat exchanger to generate hot water to be supplied at a hot water supply terminal, and hot water is supplied at a hot water supply terminal. is there.

  This is illustrated in FIG. 3 as another embodiment. The configuration of FIG. 3 is substantially different from the configuration of FIG. 1 in that a water-liquid heat exchanger 20 is provided between a tank for storing the liquid of the heat medium and a hot water supply terminal (not shown). Other configurations are substantially the same as shown in the figure, but the reference numerals and names are partially changed. That is, the liquid-refrigerant heat exchanger 5 ', the storage tank 9', and the circulating liquid inlet pipe 11 'correspond to indirectly heating the low-temperature water with heated water or a liquid other than water stored in the tank. The circulating fluid outlet pipe 12 ', the inlet temperature sensor 18', and the outlet temperature sensor 19 'are changed.

The defrosting operation control of the heat pump type water heater according to the embodiment of FIG. 3 is substantially the same as the flowchart of the defrosting operation control of the embodiment of FIG.
While the above description has been made with reference to exemplary embodiments, it will be apparent to those skilled in the art that the invention is not limited thereto and that various changes and modifications can be made within the spirit of the invention and the scope of the appended claims.

DESCRIPTION OF SYMBOLS 1 Heat pump unit 2 Tank unit 3 Connection piping 4 Compressor 5 Water-refrigerant heat exchanger 5 'Liquid-refrigerant heat exchanger 6 Pressure reducing valve 7 Evaporator 8 Fan 9 Hot water storage tank 9' Storage tank 10 Circulation pump 11 Water supply piping 11 ' Circulating fluid inlet piping 12 Hot water supply piping 12 'Circulating fluid outlet piping 13 Bypass piping 14 Switching valve 15 Outside air temperature sensor 16 Evaporator inlet temperature sensor 17 Evaporator outlet temperature sensor 18 Incoming water temperature sensor 18' Inlet temperature sensor 19 Hot water temperature sensor 19 ' Outlet temperature sensor 20 Water-liquid heat exchanger

Claims (10)

A compressor that compresses the refrigerant, a liquid-refrigerant heat exchanger that heats the liquid stored in the storage tank by the high-temperature and high-pressure refrigerant discharged from the compressor, and an expansion valve from the liquid-refrigerant heat exchanger. An evaporator that exchanges heat between low-temperature and low-pressure refrigerant flowing in through air, a storage tank that stores liquid heated by the liquid-refrigerant heat exchanger, and low-temperature liquid into the liquid-refrigerant heat exchanger. A forward pipe for sending, and a return pipe for returning the liquid heated by the liquid-refrigerant heat exchanger to the storage tank,
Performing a boiling operation of heating the low-temperature liquid and storing it in the storage tank;
In addition, a bypass pipe connecting the forward pipe and the return pipe so that the liquid flowing out from the liquid-refrigerant heat exchanger bypasses the storage tank, and the liquid flowing out from the liquid-refrigerant heat exchanger enters the storage tank. A path switching mechanism for switching between a route to be sent and a path to bypass the storage tank;
In a heat pump hot water heater that performs a defrosting operation that introduces a high-temperature refrigerant into the evaporator and dissolves frost adhering to the evaporator,
Before the defrosting operation, perform a high temperature liquid introduction operation to introduce a liquid having a temperature higher than that of the low temperature liquid into the liquid-refrigerant heat exchanger
During the defrosting operation, a heat pump type hot water heater is provided that performs a bypass circulation operation for circulating the liquid flowing out from the liquid-refrigerant heat exchanger through a bypass pipe at a lower flow rate than in the boiling operation. In the heat pump type water heater according to claim 1,
It further includes an outside air temperature detection unit that detects the outside air temperature,
A heat pump type hot water heater characterized in that the high temperature liquid introduction operation is performed when the temperature detected by the outside air temperature detection unit becomes a predetermined temperature or lower. In the heat pump type water heater according to claim 1,
A heat pump type hot water supply apparatus, wherein the path switching mechanism is switched so that the liquid flowing out from the liquid-refrigerant heat exchanger becomes a path bypassing the storage tank at the start of the high-temperature liquid introduction operation. In the heat pump type water heater according to claim 2,
A heat pump type hot water supply apparatus, wherein the path switching mechanism is switched so that the liquid flowing out from the liquid-refrigerant heat exchanger becomes a path bypassing the storage tank at the start of the high-temperature liquid introduction operation. In the heat pump type water heater according to claim 1,
An inflow liquid temperature detection unit for detecting the temperature of the liquid flowing into the liquid-refrigerant heat exchanger;
The high-temperature liquid introduction operation is terminated when the temperature detected by the inflow liquid temperature detecting unit is equal to or higher than a predetermined temperature or when a predetermined time has passed. Heat pump water heater. In the heat pump type water heater according to claim 2,
An inflow liquid temperature detection unit for detecting the temperature of the liquid flowing into the liquid-refrigerant heat exchanger;
The high-temperature liquid introduction operation is terminated when the temperature detected by the inflow liquid temperature detecting unit is equal to or higher than a predetermined temperature or when a predetermined time has passed. Heat pump water heater. In the heat pump type water heater according to claim 3,
An inflow liquid temperature detection unit for detecting the temperature of the liquid flowing into the liquid-refrigerant heat exchanger;
The high-temperature liquid introduction operation is terminated when the temperature detected by the inflow liquid temperature detecting unit is equal to or higher than a predetermined temperature or when a predetermined time has passed. Heat pump water heater. In the heat pump type water heater according to claim 4,
An inflow liquid temperature detection unit for detecting the temperature of the liquid flowing into the liquid-refrigerant heat exchanger;
The high-temperature liquid introduction operation is terminated when the temperature detected by the inflow liquid temperature detecting unit is equal to or higher than a predetermined temperature or when a predetermined time has passed. Heat pump water heater. A compressor that compresses the refrigerant, a liquid-refrigerant heat exchanger that heats the liquid stored in the storage tank by the high-temperature and high-pressure refrigerant discharged from the compressor, and an expansion valve from the liquid-refrigerant heat exchanger. An evaporator that exchanges heat between low-temperature and low-pressure refrigerant flowing in through air, a storage tank that stores liquid heated by the liquid-refrigerant heat exchanger, and low-temperature liquid into the liquid-refrigerant heat exchanger. A forward pipe for sending out, and a return pipe for returning the liquid heated by the liquid-refrigerant heat exchanger to the storage tank,
Performing a boiling operation of heating the low-temperature liquid and storing it in the storage tank;
Further, a bypass pipe that bypasses the storage tank and connects the forward pipe and the return pipe, and a path through which the liquid flowing out from the liquid-refrigerant heat exchanger is sent to the storage tank and a path that bypasses the storage tank are switched. In a heat pump type water heater comprising a path switching mechanism and an inflow liquid temperature detection unit for detecting the temperature of the liquid flowing into the liquid-refrigerant heat exchanger,
When the temperature detected by the influent temperature detector is below a predetermined temperature over a predetermined time,
The path switching mechanism is switched so that the liquid flowing out from the liquid-refrigerant heat exchanger becomes a path that bypasses the storage tank, and a liquid higher in temperature than the low-temperature liquid is introduced into the liquid-refrigerant heat exchanger. And an anti-freezing operation that circulates the liquid flowing out of the liquid-refrigerant heat exchanger through a bypass pipe at a lower flow rate than that during the boiling operation and prevents freezing of the outgoing pipe toward the liquid-refrigerant heat exchanger. A heat pump type water heater characterized by performing A compressor that compresses the refrigerant, a liquid-refrigerant heat exchanger that heats the liquid stored in the storage tank by the high-temperature and high-pressure refrigerant discharged from the compressor, and an expansion valve from the liquid-refrigerant heat exchanger. An evaporator that exchanges heat between the low-temperature and low-pressure refrigerant flowing in through air, an outgoing pipe that sends low-temperature liquid to the liquid-refrigerant heat exchanger, and a liquid heated by the liquid-refrigerant heat exchanger. A return pipe returning to the storage tank,
Performing a boiling operation of heating the low-temperature liquid and storing it in the storage tank;
In addition, a bypass pipe connecting the forward pipe and the return pipe so that the liquid flowing out from the liquid-refrigerant heat exchanger bypasses the storage tank, and the liquid flowing out from the liquid-refrigerant heat exchanger enters the storage tank. In a heat pump type water heater provided with a path switching mechanism that switches between a path to be sent and a path that bypasses the storage tank,
The path switching mechanism is switched so that the liquid flowing out from the liquid-refrigerant heat exchanger becomes a path that bypasses the storage tank, and a liquid higher in temperature than the low-temperature liquid is introduced into the liquid-refrigerant heat exchanger. After performing the high temperature liquid introduction operation,
A bypass circulation operation for performing a high-temperature refrigerant introduction operation for introducing a high-temperature refrigerant into the evaporator and circulating the liquid flowing out from the liquid-refrigerant heat exchanger through a bypass pipe at a lower flow rate than in the boiling operation. A heat pump type water heater characterized by performing.

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