JPWO2012070082A1 - Heat pump type water heater - Google Patents

Abstract

The heat pump hot water supply apparatus 100 conducts the reverse defrosting operation by causing the refrigerant discharged from the compressor 1 to conduct to the path 31 other than the path 33 positioned at the lowermost stage of the evaporator 13, and after the reverse defrosting operation is completed, the outside air When the temperature is equal to or lower than the predetermined temperature, and the passage of the predetermined time or the difference between the shell temperature of the compressor 1 and the low pressure saturation temperature is equal to or lower than the predetermined value, the refrigerant discharged from the compressor 1 is It branches between the four-way valve 2 and is conducted to a path 33 located at the lowest stage of the evaporator 13 so as to be in parallel with the water heat exchanger 3 until a predetermined time elapses.

Description

  The present invention relates to a heat pump type hot water supply apparatus using a heat pump that circulates refrigerant, and in particular, defrosting that removes frost attached to a heat exchanger that functions as an evaporator even at a low outside air temperature (for example, 0 ° or less). The present invention relates to a heat pump type hot water supply device that performs operation.

  2. Description of the Related Art Conventionally, there is a heat pump hot water supply device that uses a heat pump that circulates a refrigerant and that can perform a defrosting operation that removes frost attached to an evaporator. As such, in the method of controlling a heat pump hot water supply apparatus equipped with a refrigeration cycle incorporating a water heat exchanger that generates water by heating water, when the outside air temperature is below a predetermined temperature, water heat exchange A control method of a heat pump hot water supply apparatus that regulates the set upper limit temperature of hot water generated by a water heater has been proposed (see, for example, Patent Document 1).

  In the technique described in Patent Document 1, a defrosting operation is performed in which frost adhering to the heat source side heat exchanger is melted by guiding the refrigerant discharged from the compressor (hot gas) to the heat source side heat exchanger. It is like that. During normal defrosting operation, if the water temperature falls or the water heat exchanger temperature falls, it is judged that the water heat exchanger may freeze, and the water heat exchange is performed by opening the bypass circuit. Do not let the refrigerant flow through the water heater, or flow the refrigerant through the bypass circuit in parallel with the water heat exchanger to reduce the amount of refrigerant circulating to the water heat exchanger to prevent the water heat exchanger from freezing. It was. When the outside air temperature becomes equal to or lower than a predetermined temperature (for example, −5 ° C.), the upper limit temperature of the desired hot water is decreased (for example, 65 ° C. → 58 ° C.).

Japanese Unexamined Patent Publication No. 2009-41860 (for example, page 7, FIG. 1, etc.)

  The technique described in Patent Document 1 regulates the set upper limit temperature of hot water generated by the water heat exchanger when the outside air temperature is equal to or lower than a predetermined temperature for the purpose of reducing the burden on the compressor. It was like that. If it does in this way, the hot water temperature in a hot water tank will be less than 60 degreeC, and there existed a possibility that the hot water temperature in a hot water tank required for prevention of Resinellosis 60 degreeC could not be maintained. The recommended temperature of the hot water stored in the hot water storage tank for suppressing the reproduction of Legionella is 60 ° C. or higher.

  The present invention has been made in order to solve the above-described problems, and requires a hot water temperature (for example, 65, which is required even when the temperature is low outside air (for example, when the outside air temperature is 0 ° C. or lower). It is an object of the present invention to provide a heat pump type hot water supply apparatus that can maintain the temperature (° C.) and can efficiently perform the defrosting operation of the evaporator.

  The heat pump hot water supply apparatus according to the present invention has a main circuit in which a compressor, a flow switching device, a water heat exchanger, a throttling device, and an evaporator are connected by piping, and the flow of the refrigerant is switched by the flow switching device. A heat pump hot water supply device for performing a reverse defrosting operation by causing the refrigerant discharged from the compressor to flow into the evaporator, and discharging from the compressor to a path other than the path located below the evaporator The reverse defrosting operation is performed with the refrigerant conducted, and after the reverse defrosting operation is completed, the outside air temperature is equal to or lower than a predetermined temperature, and the passage of the predetermined time or the compressor shell temperature and the low pressure saturation temperature The refrigerant discharged from the compressor is branched between the compressor and the flow path switching device and in parallel with the water heat exchanger. Path at the bottom of It is intended to conduct until a predetermined time elapses.

  In the heat pump hot water supply apparatus according to the present invention, after the end of the reverse defrosting operation, the outside air temperature is equal to or lower than a predetermined temperature, and the elapse of a predetermined time or the difference between the compressor shell temperature and the low pressure saturation temperature is equal to or lower than a predetermined value. When this is the case, the refrigerant discharged from the compressor is branched between the compressor and the flow path switching device, and a predetermined time elapses in a path located below the evaporator so as to be in parallel with the water heat exchanger. Therefore, the required hot water temperature (for example, 65 ° C.) can be maintained even when the outside air is low, and the refrigerant is not accumulated in the path located below the evaporator during the hot water supply operation. It is possible to perform the defrosting operation efficiently without deteriorating the heating capacity of the defrosting due to insufficient refrigerant amount during the defrosting operation.

It is a refrigerant circuit figure which shows an example of the refrigerant circuit structure of the heat pump hot-water supply apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows roughly an example of the pass pattern of the evaporator of the heat pump hot-water supply apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of control operation at the time of the defrost operation of the heat pump apparatus which concerns on embodiment of this invention. It is a refrigerant circuit figure which shows another example of the refrigerant circuit structure of the heat pump hot-water supply apparatus which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a refrigerant circuit diagram illustrating an example of a refrigerant circuit configuration of a heat pump water heater 100 according to an embodiment of the present invention. An example of the circuit configuration of the heat pump hot water supply apparatus 100 will be described with reference to FIG. The heat pump hot water supply apparatus 100 performs a hot water supply operation using a refrigeration cycle (heat pump cycle) for circulating a refrigerant. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

  As shown in FIG. 1, a heat pump hot water supply apparatus 100 includes a compressor 1, a four-way valve 2 as a flow path switching valve, a water heat exchanger 3 (for example, a refrigerant circulating in the refrigerant circuit and water circulating in the water circuit). A load side heat exchanger that exchanges heat with a heat medium), a liquid receiver 6, a double pipe heat exchanger 7, a throttling device 11, and an evaporator 13 connected by a refrigerant pipe 20 as a main circuit. Yes. That is, the heat pump hot water supply apparatus 100 can perform a hot water supply operation by circulating the refrigerant in the main circuit.

  Further, the heat pump hot water supply apparatus 100 includes an injection pipe 21 that branches the liquid pipe on the outlet side of the liquid receiver 6 and leads to the compressor 1 through the secondary side of the double pipe heat exchanger 7. Thereby, the fall of a heating capability can be suppressed also in a cold district. An injection electronic expansion valve 8 is provided between the branch point of the injection tube 21 and the double tube heat exchanger 7. An injection solenoid valve 9 is provided in the injection pipe 21 between the double pipe heat exchanger 7 and the compressor 1. Furthermore, the heat pump hot water supply apparatus 100 includes a first bypass pipe 23 that branches off the refrigerant pipe 20 on the outlet side of the water heat exchanger 3 and connects to the outlet side of the double pipe heat exchanger 7. The first bypass pipe 23 is provided with a first check valve 10.

  The heat pump hot water supply device 100 includes a second bypass pipe 24 that bypasses the expansion device 11. A second check valve 12 is provided in the second bypass pipe 24. Further, the heat pump hot water supply apparatus 100 includes a hot gas conduction pipe 22 for guiding refrigerant discharged from the compressor 1 (hot gas) to the evaporator 13. The hot gas conducting tube 22 is provided with a hot gas solenoid valve 14. A high pressure sensor 15 is provided at the discharge portion of the compressor 1, a low pressure sensor 16 is provided at the suction portion of the compressor 1, a shell temperature sensor 17 is provided at the lower portion of the compressor 1, and an outside air temperature is provided near the evaporator 13. Each sensor 18 is provided.

  The compressor 1 compresses the refrigerant sucked from the suction part, the injection pipe 21 and the hot gas conduction pipe 22 to bring it into a high temperature / high pressure state. The compressor 1 may be configured by a capacity control type in which the rotation speed can be controlled by an inverter, for example. The compressor 1 has a structure capable of injecting (injecting) the refrigerant flowing through the injection pipe 21 into the compression chamber in the compressor 1. The compressor 1 has a structure that allows the refrigerant flowing through the hot gas conduction pipe 22 to flow into the compression chamber in the compressor 1.

  The four-way valve 2 switches the refrigerant flow between the reverse defrosting operation and the hot water supply operation. The water heat exchanger 3 delivers the warm heat stored in the refrigerant to the water circuit side. The water circuit inlet connected to the water heat exchanger 3 is referred to as a water circuit inlet 4, and the water circuit outlet is referred to as a water circuit outlet 5. The water circuit inlet 4 and the water circuit outlet 5 are connected to a hot water tank (not shown) to form a water circuit. The hot water boiled by the water heat exchanger 3 is stored in the hot water storage tank.

  The liquid receiver 6 is provided on the outlet side of the water heat exchanger 3 and stores excess refrigerant. Heat is exchanged between the refrigerant flowing out of the double pipe heat exchanger 7 and the liquid receiver 6 and flowing through the injection pipe 21 and the refrigerant flowing through the refrigerant pipe 20. This double pipe heat exchanger 7 has a liquid pipe (referred to as liquid pipe 20a) through which the liquid refrigerant flowing out from the liquid receiver 6 flows, and a pipe diameter larger than the pipe diameter of the liquid pipe 20a. The injection pipe 21 is arranged so as to cover the pipe, and a pipe part (not shown) having a pipe diameter larger than the pipe diameter of the injection pipe 21 and forming a closed space. The liquid pipe 20a side of the double pipe heat exchanger 7 is referred to as a primary side, and the injection pipe 21 side is referred to as a secondary side.

  The expansion device 11 has a function as a pressure reducing valve or an expansion valve, and expands the refrigerant by reducing the pressure. The expansion device 11 may be constituted by, for example, an electronic expansion valve whose opening degree can be variably controlled. The evaporator 13 evaporates the refrigerant by exchanging heat between air (outside air) supplied from a fan (not shown) and the like and the refrigerant. The refrigerant pipe 20 connects the component devices. The liquid pipe 20 a, the injection pipe 21, the hot gas conduction pipe 22, the first bypass pipe 23, and the second bypass pipe 24 each constitute a part of the refrigerant pipe 20.

  The injection electronic expansion valve 8 expands the refrigerant flowing through the injection pipe 21 by reducing the pressure. The injection electronic expansion valve 8 may be constituted by, for example, an electronic expansion valve whose opening degree can be variably controlled. The electromagnetic solenoid valve 9 for injection is controlled to be opened and closed, and adjusts the inflow of refrigerant into the injection pipe 21. The first check valve 10 allows the refrigerant flow in one direction (from the expansion device 11 toward the water heat exchanger 3). The second check valve 12 allows the flow of the refrigerant in one direction (from the evaporator 13 toward the inlet side of the first bypass pipe 23). The hot gas solenoid valve 14 is controlled to be opened and closed, and adjusts the inflow of refrigerant into the hot gas conduction pipe 22.

  The high pressure sensor 15 detects the pressure of the refrigerant discharged from the compressor 1. The low pressure sensor 16 detects the pressure of the refrigerant sucked into the compressor 1. The shell temperature sensor 17 detects the shell temperature of the compressor 1. The outside air temperature sensor 18 detects the temperature of outside air that exchanges heat with the evaporator 13. Information (pressure information, temperature information) detected by these sensors is sent to the control device 50, and the drive frequency of the compressor 1, switching of the four-way valve 2, opening of the expansion device 11, the electronic expansion valve for injection. 8 is used for opening / closing the electromagnetic valve 9 for injection, opening / closing the electromagnetic valve 14 for hot gas, and the like.

  FIG. 2 is a schematic diagram schematically showing an example of a pass pattern of the evaporator 13 of the heat pump hot water supply apparatus 100. The evaporator 13 will be described in more detail with reference to FIG. As shown in FIG. 2, the evaporator 13 has an inlet header 31 provided on the inlet side, and the refrigerant branches into and flows into a plurality of paths, and the outlet header 32 provided with the refrigerant flowing out of the plurality of paths on the outlet side. It is supposed to join at. FIG. 2 illustrates a state where the path of the evaporator 13 is a path 30a to a path 30h, that is, eight branches.

  However, the lowermost path 33 of the evaporator 13 is not communicated with other paths (path 31a to path 31h). That is, the path 33 does not communicate with the inlet header 31 and the outlet header 32. The path 33 is connected to the hot gas solenoid valve 14 on the inlet side and the suction portion of the compressor 1 on the outlet side via another pipe (hot gas conduction pipe 22). Therefore, during hot water supply operation (during heating operation), the hot gas solenoid valve 14 is controlled to be closed, so that the refrigerant does not flow. A unit base 34 is provided below the evaporator 13. That is, the evaporator 13 is disposed on the unit base 34. In addition, in FIG. 2, as a preferred example, a state where one of the paths 33 located at the lowermost stage is not in communication with the other paths (paths 31 a to 31 h) is shown as an example. A plurality of stages of paths at the lower part (lower side from the center of the evaporator 13 in the height direction) may function in the same manner as the path 33.

Examples of the refrigerant circulating through the refrigerant circuit constituting the heat pump hot water supply apparatus 100 include single refrigerants such as R-22, R-134a, and R-32, and pseudo-azeotropic refrigerant mixtures such as R-410A and R-404A. Non-azeotropic refrigerants such as R-407C, tetrafluoropropene which is a refrigerant containing a double bond in the chemical formula and having a chemical formula represented by C ₃ H ₂ F ₄ and a relatively low global warming potential (HFO-1234yf or HFO-1234ze) or a mixture thereof, or a natural refrigerant such as CO ₂ or propane can be used. In consideration of the global environment, it is desirable to use a mixed refrigerant containing R-32 or R-32 and tetrafluoropropene (HFO-1234yf or HFO-1234ze) having a small warming potential. In order to meet the demand for high temperature hot water (for example, storing 65 ° C. in a hot water storage tank), refrigerants such as R407C, R134a, HFO-1234yf, and HFO-1234ze are particularly desirable.

Here, the operation of the heat pump hot water supply apparatus 100 will be described.
[Hot water operation]
During the hot water supply operation, the refrigerant discharged from the compressor 1 is guided to the water heat exchanger 3 via the four-way valve 2. The refrigerant flowing into the water heat exchanger 3 exchanges heat with a heat medium such as water flowing from the water circuit inlet 4 to heat the water. And the heated heat medium (here hot water) is guide | induced to the hot water storage tank from the water circuit exit 5, and is stored. Since the piping from the hot water tank communicates with the water circuit inlet 4, the heat medium is circulated between the water heat exchanger 3 and the hot water tank.

  The refrigerant that has heated the heat medium flows out from the water heat exchanger 3, passes through the liquid receiver 6, is branched, partly flows into the liquid pipe 20 a, and the rest flows into the injection pipe 21. In the double pipe heat exchanger 7, heat exchange is performed between the primary refrigerant flowing through the liquid pipe 20 a and the secondary refrigerant flowing through the injection pipe 21 and throttled by the injection electronic expansion valve 8. It is. That is, in the double pipe heat exchanger 7, heat exchange is performed between the refrigerant flowing through the liquid pipe 20 a guided to the closed space and the refrigerant flowing through the injection pipe 21. Then, the liquid refrigerant supercooled by the secondary refrigerant is guided to the expansion device 11 and then flows into the evaporator 13.

  At this time, in the evaporator 13, the refrigerant passes through the paths 30a to 30h excluding the lowermost path 33, and performs heat exchange between the refrigerant and the outside air. The refrigerant having exchanged heat with the outside air joins at the outlet header 32 and is sucked again into the compressor 1 through the four-way valve 2. Further, during the hot water supply operation, the hot gas solenoid valve 14 is closed and the refrigerant does not flow through the path 33 located at the lowest stage of the evaporator 13.

  The refrigerant flowing into the injection pipe 21 passes through the injection electronic expansion valve 8 and then exchanges heat with the primary liquid refrigerant in the double pipe heat exchanger 7. This refrigerant flows out of the double-pipe heat exchanger 7 and then passes through an injection electromagnetic valve 9 that is controlled to open when injection is required, and enters an intermediate portion (injection port) of the compression chamber in the compressor 1. It is guided and the discharge gas of the compressor 1 is cooled.

  In addition, if the hot water supply operation is continuously executed in a cold district or the like, frost adheres to the evaporator 13. If the frost adhering to the evaporator 13 is left as it is, the heat exchange capability of the evaporator 13 is reduced. Then, the desired ability cannot be exhibited in the hot water supply operation. Therefore, in the heat pump hot water supply apparatus 100, a defrosting operation for removing frost adhering to the evaporator 13 is appropriately executed. The defrosting operation performed by the heat pump hot water supply apparatus 100 includes a reverse defrosting operation in which the refrigerant flow is reversed and the refrigerant discharged from the compressor 1 flows into the evaporator 13, and the refrigerant discharged from the compressor 1 (hot gas). ) And a hot gas defrosting operation in which part of the gas is branched into the evaporator 13. Hereinafter, the defrosting operation will be described in detail.

[Defrosting operation (reverse defrosting operation + hot gas defrosting operation)]
Next, the refrigerant circuit during the defrosting operation will be described.
During the reverse defrosting operation, the refrigerant discharged from the compressor 1 is guided to the evaporator 13 by switching the four-way valve 2. At this time, in the evaporator 13, the refrigerant passes through the paths 30 a to 30 h excluding the path 33, and the frost attached to the evaporator 13 is dissolved. The refrigerant that exchanges heat with the frost adhering to the evaporator 13 is joined at the outlet header 32 and flows through the second bypass pipe 24 and the first bypass pipe 23, and the expansion device 11, the double pipe heat exchanger 7, and the liquid receiver. It bypasses the vessel 6, passes through the water heat exchanger 3, and is sucked again into the compressor 1 through the four-way valve 2. During the reverse defrosting operation, the water heat exchanger 3 circulates the heat medium so that the heat medium does not freeze.

  In addition, after the reverse defrosting operation is completed, the hot gas defrosting operation can be performed by opening-controlling the hot gas solenoid valve 14. By doing so, it becomes possible to cause the refrigerant to flow into the hot gas conduction pipe 22 so as to be in parallel with the refrigerant circuit in the hot water supply operation. That is, by opening the hot gas solenoid valve 14, a part of the refrigerant discharged from the compressor 1 branches from between the compressor 1 and the four-way valve 2 and passes through the hot gas solenoid valve 14. Then, a part of the refrigerant that flows into the path 33 located at the lowest stage of the evaporator 13 and is discharged from the compressor 1 flows into the water heat exchanger 3 through the four-way valve 2. The refrigerant flowing into the path 33 exchanges heat with the frost attached to the lowermost stage of the evaporator 13, then flows in from the evaporator 13, and is guided to the suction side of the compressor 1.

  FIG. 3 is a flowchart showing the flow of the control operation during the defrosting operation (reverse defrosting operation, hot gas defrosting operation). Based on FIG. 3, the control operation during the defrosting operation will be described. Control device 50 starts the defrosting operation when it is determined that predetermined conditions (for example, the accumulated operation time of compressor 1, a decrease in outside air temperature, etc.) are satisfied (step S101). The control device 50 first performs the reverse defrosting operation by switching the four-way valve 2 and flowing hot gas through the path 30a to the path 30h of the evaporator 13 (step S102).

  When it is determined that a predetermined condition (for example, a predetermined time has elapsed) is satisfied, control device 50 ends the reverse defrosting operation (step S103). Thereafter, the control device determines whether or not the outside air temperature is a predetermined temperature or lower (for example, 0 ° C. or lower) (step S104). When the outside air temperature is not equal to or lower than the predetermined temperature (step S104; NO), the control device 50 switches the four-way valve 2 and executes a hot water supply operation (step S110).

  On the other hand, when the outside air temperature is equal to or lower than the predetermined temperature (step S104; YES), the control device 50 stands by until a predetermined time (for example, 10 seconds) elapses after the reverse defrosting operation ends (step S105). When a predetermined time has elapsed since the end of the reverse defrosting operation (step S105; YES), the controller 50 opens the hot gas solenoid valve 14 and starts the hot gas defrosting operation (step S106). ). At this time, the standby for a predetermined time is to switch the four-way valve 2 after the reverse defrosting operation is completed, but after the four-way valve 2 is reliably switched by a differential pressure before and after the four-way valve 2, the hot gas defrosting is performed. This is in order to be able to shift to driving.

  The control device 50 determines whether or not a predetermined time (for example, about 5 minutes) has elapsed since the start of the hot gas defrosting operation (step S107). When it is determined that the predetermined time has elapsed since the start of the hot gas defrosting operation (step S107; YES), the control device 50 ends the hot gas defrosting operation (step S108), and the hot gas electromagnetic The valve 14 is closed and switched to a hot water supply operation (step S110).

  On the other hand, when it is determined that the predetermined time has not elapsed since the start of the hot gas defrosting operation (step S107; NO), the control device 50 may return the liquid refrigerant to the compressor 1. Thus, the shell temperature of the compressor 1 detected by the shell temperature sensor 17 and the low pressure detected by the low pressure sensor 16 are converted into a low pressure saturated gas temperature, and (compressor shell temperature−low pressure saturated gas temperature) is obtained. It is determined whether the value is equal to or less than a predetermined value (step S109).

  If it is determined that (compressor shell temperature−low pressure saturated gas temperature) is not equal to or lower than the predetermined value (step S109; NO), has the control device 50 elapsed since the start of the hot gas defrosting operation? The process returns to the determination of whether or not (step S107). On the other hand, if it is determined that (compressor shell temperature−low pressure saturated gas temperature) is equal to or lower than the predetermined value (step S109; YES), the controller 50 determines that there is a possibility of liquid back and removes the hot gas. Even if the predetermined time has not elapsed since the start of the frost operation, the hot gas defrosting operation is terminated to protect the compressor 1 (step S108). Then, the hot gas solenoid valve 14 is closed and switched to the hot water supply operation (step S110).

  When the evaporator 13 has a lot of frost due to low outside air or snowfall, or when snow falls on the lower part of the evaporator 13, the refrigerant accumulates in the path 33 located at the lowest stage of the evaporator 13. There are times. In such a case, the refrigerant cannot be used at the time of the defrosting operation, and the amount of the refrigerant becomes insufficient, and the heating capacity may be reduced. Further, since the path 33 located at the lowermost stage of the evaporator 13 is provided in the vicinity of the unit base 34, the defrosting operation is performed during the defrosting operation by the snowfall or the cold unit base 34 accumulated in the unit base 34. I was deprived of the heat required.

  Therefore, in the heat pump hot water supply apparatus 100, the evaporator 13 is configured to separate the path 33 located at the lowermost stage near the unit base 34 from the other paths 30a to 30h. Accordingly, during the hot water supply operation, the refrigerant is not stored in the path 33 located at the lowest stage of the evaporator 13, and therefore the heating capacity of the defrosting can be prevented from being reduced due to the insufficient refrigerant amount during the defrost operation. became. Moreover, even at the time of low outside air, the fall of hot water supply capability can be suppressed and the hot water supply temperature can be kept high (for example, 65 ° C.). Therefore, reproduction of Legionella bacteria etc. in a hot water tank can be suppressed.

  Further, the heat pump hot water supply apparatus 100 performs the reverse defrosting operation via the paths 30a to 30h of the evaporator 13 and then flows hot gas into the path 33 positioned at the lowest stage of the evaporator 13. Yes. Therefore, at the time of defrosting other than the pass 33 located at the lowermost stage of the evaporator 13, the water is dissolved by the reverse defrosting operation, and the dripping water is deprived of heating power without excessively heating the dripped water. The hot gas defrosting operation can now be executed without being interrupted. For this reason, it becomes possible to reliably defrost the vicinity of the lower part of the evaporator 13 and the unit base 34, which are the starting points of the remaining ice, by the hot gas defrosting operation.

  FIG. 4 is a refrigerant circuit diagram illustrating another example of the refrigerant circuit configuration of the heat pump water heater 100 according to the embodiment of the present invention. Based on FIG. 4, another example of the circuit configuration of the heat pump hot water supply apparatus 100 will be described.

  When performing the hot gas defrosting operation, the low pressure of the refrigerant sucked into the compressor 1 and the high pressure of the refrigerant discharged from the compressor 1 are increased during the defrosting of the lowermost stage of the evaporator 13. Therefore, in FIG. 4, in order to maintain the design pressure of the evaporator 13 at a low value, the first hot gas throttle device 25 and the path 33 of the evaporator 13 are provided between the compressor 1 and the hot gas solenoid valve 14. A second hot gas throttling device 26 is provided between the suction of the compressor 1.

  By providing the first hot gas throttling device 25 and the second hot gas throttling device 26, even during the hot gas defrosting operation, the low pressure of the refrigerant sucked into the compressor 1 and the refrigerant discharged from the compressor 1 are discharged. The high pressure of the refrigerant does not rise abnormally. Therefore, the design pressure of the evaporator 13 can be maintained at a low value, which can contribute to further improvement in reliability. FIG. 4 shows an example in which the first hot gas throttling device 25 and the second hot gas throttling device 26 are constituted by capillaries. However, the present invention is not limited to this, such as an expansion valve. You may make it comprise with a diaphragm | throttle device.

  In addition, it is good to determine the refrigerant | coolant to be used according to the purpose and use to which the heat pump hot-water supply apparatus 100 is applied, the number of the water heat exchangers 3, and the number of temperature sensors and pressure sensors. The control device 50 may be configured by a microcomputer or the like that can control the heat pump hot water supply device 100 in an integrated manner.

1 compressor, 2 four-way valve, 3 water heat exchanger, 4 water circuit inlet, 5 water circuit outlet, 6 liquid receiver, 7 double pipe heat exchanger, 8 electronic expansion valve for injection, 9 electromagnetic valve for injection, 10 First check valve, 11 Throttle device, 12 Second check valve, 13 Evaporator, 14 Hot gas solenoid valve, 15 High pressure sensor, 16 Low pressure sensor, 17 Shell temperature sensor, 18 Outside air temperature sensor, 20 Refrigerant piping 20a liquid pipe, 21 injection pipe, 22 hot gas conduction pipe, 23 first bypass pipe, 24 second bypass pipe,
25 First hot gas throttle device, 26 Second hot gas throttle device, 30a pass, 30b pass, 30c pass, 30d pass, 30e pass, 30f pass, 30g pass, 31 inlet header, 32 outlet header, 33 pass, 34 units Base, 50 control device, 100 heat pump hot water supply device.

Claims (5)

A compressor, a flow path switching device, a water heat exchanger, a throttling device, and a main circuit connected by an evaporator, and the flow of the refrigerant is switched by the flow path switching device to discharge refrigerant discharged from the compressor. A heat pump hot water supply device that performs reverse defrosting operation by flowing into the evaporator,
The reverse defrosting operation is performed by passing the refrigerant discharged from the compressor through a path other than the path located below the evaporator,
After the end of the reverse defrosting operation, when the outside air temperature is equal to or lower than the predetermined temperature, and the difference between the passage of the predetermined time or the shell temperature of the compressor and the low pressure saturation temperature is equal to or lower than the predetermined value
The refrigerant discharged from the compressor is branched between the compressor and the flow path switching device, and a predetermined time elapses in a path located below the evaporator so as to be in parallel with the water heat exchanger. A heat pump hot water supply device that is conducted until it is turned on. A hot gas conduction pipe that branches a pipe between the compressor and the flow path switching device and connects to a suction side of the compressor after passing through a path located at a lower portion of the evaporator;
A hot gas solenoid valve installed in the hot gas conducting pipe,
The heat pump hot water supply apparatus according to claim 1, wherein the refrigerant discharged from the compressor is conducted to a path located below the evaporator through the hot gas conducting pipe by opening and closing the hot gas solenoid valve. A liquid receiver installed between the water heat exchanger and the expansion device;
A double-tube heat exchanger installed between the expansion device and the receiver;
An injection pipe that branches a refrigerant pipe between the double pipe heat exchanger and the liquid receiver, and is connected to an injection port of the compressor via the double pipe heat exchanger;
An electronic expansion valve for injection installed on the upstream side of the double pipe heat exchanger of the injection pipe;
The heat pump hot water supply apparatus according to claim 1, further comprising: an injection electromagnetic valve installed between the double pipe heat exchanger of the injection pipe and the compressor. The double pipe heat exchanger, a first bypass pipe bypassing the liquid receiver;
A second bypass pipe that bypasses the throttle device;
A first check valve installed in the first bypass pipe;
A second check valve installed in the second bypass pipe,
The heat pump hot-water supply apparatus according to claim 3, wherein during the reverse defrosting operation, the refrigerant that has flowed out of the evaporator is sucked into the compressor through the second bypass pipe and the first bypass pipe. A first hot gas throttling device installed between the compressor of the hot gas conducting pipe and the hot gas solenoid valve;
The heat pump hot-water supply apparatus as described in any one of Claims 1-4 provided with the 2nd hot gas throttling apparatus installed between the said evaporator of the said hot gas conduction pipe | tube, and the said compressor.

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