JP2012225580A - Heat pump water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a high-speed and efficient defrost operation while controlling water shortage in a hot water tank.SOLUTION: The heat pump water heater includes a refrigerant cycle circuit and a hot water supply circuit. The refrigerant cycle circuit is formed by connecting a compressor 1, a user side heat exchanger 3, an expansion valve 4, and a heat source side heat exchanger 5 in this order by a refrigerant pipe 13. The hot water supply circuit is composed of the hot water tank 6, a first water pipe 21 of which one end is connected to a water inlet of the user side heat exchanger 3, a water pump 7 installed in the first water pipe 21, a second water pipe 22 to connect a water outlet of the user side heat exchanger 3 and an upper part of the hot water tank 6, a first three-way valve 8 installed at the other end of the first water pipe 21, a lower pipe 20 to connect the first three-way valve 8 and a lower part of the hot water tank 6, and an upper pipe 19 to connect the first three-way valve 8 and the upper part of the hot water tank 6. In the defrost operation of the heat source side heat exchanger 5 by reversing the refrigerant flow in the refrigerant cycle circuit, the first three-way valve 8 is controlled to adjust the temperature of water flowing into the user side heat exchanger 3.

Description

  The present invention relates to a heat pump water heater.

  Conventionally, a heat pump device such as an air conditioner or a heat pump water heater is composed of a refrigeration cycle including a compressor, a use side heat exchanger, an expansion means, and a heat source side heat exchanger, and the refrigeration cycle is filled with a refrigerant. Yes. The refrigerant compressed by the compressor becomes a high-temperature and high-pressure gas refrigerant and is sent to the use side heat exchanger (condenser). The refrigerant flowing into the use side heat exchanger is liquefied by releasing heat into water. On the other hand, hot water is produced | generated by heating water in a utilization side heat exchanger.

  The liquefied refrigerant is depressurized by the expansion means to be in a gas-liquid two-phase state, gasified by absorbing heat from ambient air in the heat source side heat exchanger (evaporator), and then returned to the compressor. At this time, when the ambient air temperature of the heat source side heat exchanger is low and the evaporation temperature of the refrigerant is lower than 0 ° C., frost is generated on the fin surface of the heat source side heat exchanger. When frost is generated, the hot water supply capacity is reduced due to a decrease in the air volume and an increase in thermal resistance, and therefore a defrosting operation that periodically removes frost is required.

  As the defrosting operation, reverse defrosting is known in which the direction in which the refrigerant flows is reversed and defrosting is performed using hot water in the hot water storage tank as a heat source. In reverse defrosting, the refrigerant flow is reversed to melt the frost of the heat source side heat exchanger using the use side heat exchanger as an evaporator and the heat source side heat exchanger as a condenser. At this time, since the direction of water flow does not change, cold water enters the utilization side heat exchanger acting as an evaporator from the lower part of the hot water storage tank, and is further cooled in the utilization side heat exchanger to the upper part of the hot water storage tank. Will return. In this case, since low-temperature water is used as a heat source, there is a problem that the defrosting time becomes long, and water cooled by the use side heat exchanger returns to the upper part of the tank, so that it is stored in the upper part of the tank. There is a problem that hot water for hot water supply is cooled and cannot be supplied.

  Therefore, in the heat pump hot water supply device, not only the refrigerant flow during reverse defrosting but also the water flow is reversed, hot water is put into the use side heat exchanger acting as an evaporator, and the cooled water is stored in the hot water A heat pump hot water supply device that returns to the bottom of the tank is known (see, for example, Patent Document 1). In this apparatus, since hot water is used as a heat source, the defrosting time is shortened. Moreover, since the water cooled by the utilization side heat exchanger is returned to the lower part of the hot water storage tank, it is possible to avoid the hot water in the upper part of the hot water storage tank being cooled.

JP 58-214759 A

  However, when the flow of water is reversed during reverse defrosting as in the above-described conventional device, hot hot water stored in the upper part of the hot water storage tank is used as a heat source. For this reason, depending on the usage of hot water, the amount of hot water required for hot water supply in the hot water storage tank is reduced, and there is a possibility that the problem of running out of hot water, which cannot be performed when hot water supply is desired, may occur.

  The present invention has been made to solve the above-described problems, and provides a heat pump hot water supply apparatus capable of performing a high-efficiency and high-efficiency defrosting operation while suppressing hot water in a hot water storage tank. Objective.

  A heat pump hot water supply apparatus according to the present invention includes a compressor that compresses a refrigerant, a use side heat exchanger for heating water by the refrigerant compressed by the compressor, an expansion valve, and a heat source side heat exchanger. A refrigeration cycle circuit, a hot water storage tank, a first water pipe whose one end is connected to the water inlet of the use side heat exchanger, and a first water pipe are provided in this order. A water pump, a second water pipe connecting the water outlet of the use side heat exchanger and the upper part of the hot water storage tank, a mixing valve disposed at the other end of the first water pipe, the mixing valve and the hot water storage A hot water supply circuit having a lower pipe that connects the lower part of the tank and an upper pipe that connects the upper part of the connection between the mixing valve and the lower pipe in the hot water storage tank, and controls the refrigeration cycle circuit and the hot water supply circuit And a mixing valve, the amount of water flowing through the lower pipe The control means is configured to be able to adjust the ratio with the amount of water flowing through the upper pipe, and the control means controls the mixing valve during the defrosting operation in which the refrigerant flowing through the refrigeration cycle circuit is reversely flowed to defrost the heat source side heat exchanger. The temperature of the water flowing into the use side heat exchanger is adjusted.

  ADVANTAGE OF THE INVENTION According to the heat pump hot water supply apparatus of this invention, the heat pump hot water supply apparatus which can perform a high-speed and highly efficient defrost operation can be provided, suppressing the hot water shortage in a hot water storage tank.

It is a figure which shows schematic structure of the heat pump hot-water supply apparatus in Embodiment 1 of this invention. It is a figure for demonstrating the flow of the water of the tank unit 200 at the time of boiling operation. It is a figure which shows the time change of the heating capability in the utilization side heat exchanger. It is a figure for demonstrating the flow of the refrigerant | coolant and water at the time of a defrost operation. It is a figure for demonstrating an example of the flow of water at the time of a defrost operation. It is a flowchart of the routine in which the heat pump hot-water supply apparatus of this Embodiment 1 performs a defrost operation. It is a figure which shows the modification of the heat pump hot-water supply apparatus of this Embodiment 1. It is a figure which shows the modification of the heat pump hot-water supply apparatus of this Embodiment 1. It is a figure which shows the modification of the heat pump hot-water supply apparatus of this Embodiment 1. It is a figure which shows schematic structure of the heat pump hot-water supply apparatus in Embodiment 2 of this invention. It is a flowchart of the routine in which the heat pump hot-water supply apparatus of this Embodiment 2 performs a defrost operation. It is a figure which shows schematic structure of the heat pump hot-water supply apparatus in Embodiment 3 of this invention. It is a flowchart of the routine in which the heat pump hot-water supply apparatus of this Embodiment 3 performs a defrost operation.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited by this embodiment.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
FIG. 1 is a diagram showing a schematic configuration of a heat pump hot water supply apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the heat pump water heater of this embodiment includes a heat pump unit 100 and a tank unit 200. In the heat pump unit 100, a compressor 1, a four-way valve 2, a use side heat exchanger 3, an expansion valve 4 and a heat source side heat exchanger 5 are mounted. A cycle circuit is formed. As shown in FIG. 1, the four-way valve 2 is disposed so as to intervene before and after the compressor 1 in the refrigerant pipe 13, and the flow direction of the refrigerant flowing through the refrigerant pipe 13 is switched by switching the ports to be communicated. It is configured to be possible.

  In the tank unit 200, a water pump 7 that sends water (hot water) that is a load-side medium to the use-side heat exchanger 3 and high-temperature water that is generated by being heated by the use-side heat exchanger 3 are stored. A hot water storage tank 6 is mounted. The water pump 7 is configured such that operation / stop switching and flow rate adjustment are possible by controlling the number of rotations of the pump by the control unit. The water pump is disposed in the middle of the first water pipe 21, and one end of the first water pipe 21 is connected to the water inlet of the use side heat exchanger 3. The water outlet of the use side heat exchanger 3 and the upper part of the hot water storage tank 6 are connected by a second water pipe 22. The other end of the first water pipe 21 is connected to the first three-way valve 8. The upper and lower parts of the hot water storage tank 6 are connected to the three-way valve 8 via an upper pipe 19 and a lower pipe 20, respectively. Furthermore, the lower part of the hot water storage tank 6 and the downstream side of the use side heat exchanger 3 in the second water pipe 22 are connected by a third water pipe 24, and the second three-way valve 9 is arranged at the connection part. It is installed. In the middle of the third water pipe 24, the first temperature detecting means 10 is disposed. A second temperature detecting means 11 is disposed in the middle of the pipe 12 for supplying city water (higher than 0 ° C.) to the lower part of the hot water storage tank 6.

[Operation of Embodiment 1]
Next, the operation | movement operation | movement with the heat pump hot-water supply apparatus of this Embodiment 1 is demonstrated.

(Boiling operation)
First, the heating operation of the heat pump type hot water supply apparatus according to the first embodiment will be described. In the boiling operation, the heat pump unit 100 and the tank unit 200 are operated, low-temperature water is discharged from the lower part of the hot water storage tank 6 by the water pump 7 and sent to the hot water storage tank 6, and the refrigerant on the use side heat exchanger 3 In this operation, the water is boiled to high temperature water by heat exchange, and the high temperature water is returned to the upper part of the hot water storage tank 6.

  As shown in FIG. 1, in the heat pump unit 100, the refrigerant compressed by the compressor 1 becomes a high-temperature and high-pressure gas refrigerant, and is sent to the use side heat exchanger 3 through the four-way valve 2. The refrigerant flowing into the use side heat exchanger 3 is liquefied by releasing heat into water. The liquefied refrigerant flows into the expansion valve 4. The liquid refrigerant is decompressed by the expansion valve 4 to be in a gas-liquid two-phase state, sent to the heat source side heat exchanger 5, gasified by absorbing heat from the air, and returned to the compressor 1.

  FIG. 2 is a view for explaining the flow of water in the tank unit 200 during the boiling operation. As shown in FIG. 2, in the tank unit 200, the water sent from the lower part of the hot water storage tank 6 to the use side heat exchanger 3 through the first water pipe 21 by the water pump 7 is used on the use side heat exchanger 3. Then, heat is received from the refrigerant to become hot hot water, and returns to the upper part of the hot water storage tank 6 through the second water pipe 22. With this configuration, temperature stratification is generated, such as hot water in the upper part of the hot water tank 6 and cold water in the lower part, so that hot water can be taken out from the upper part of the hot water tank 6 when hot water is supplied. Yes.

(Defrosting operation)
Next, a defrosting operation operation of the heat pump hot water supply apparatus according to the first embodiment will be described. The defrosting operation is an operation for melting the frost adhering to the heat source side heat exchanger 5 with the heat of the refrigerant discharged from the compressor 1. When the evaporating temperature of the refrigerant in the heat source side heat exchanger 5 is 0 ° C. or less, moisture present in the air adheres to the heat source side heat exchanger 5 and accumulates as frost. The amount of deposition increases with time. FIG. 3 is a diagram illustrating a change over time in the heating capacity in the use side heat exchanger 3. As shown in this figure, when the heat resistance and the ventilation resistance increase due to frost adhering to the fins that are a part of the heat source side heat exchanger 5, as shown in FIG. Decreases with. For this reason, when frost has adhered to the heat source side heat exchanger 5, it is necessary to temporarily interrupt the boiling operation and periodically perform the defrosting operation to remove the frost from the heat source side heat exchanger 5. .

  FIG. 4 is a diagram for explaining the flow of refrigerant and water during the defrosting operation. As shown in this figure, when the defrosting operation is performed, the refrigerant flows backward by switching the four-way valve 2, and the high-temperature and high-pressure refrigerant is introduced into the heat source side heat exchanger 5. Thereby, the heat source side heat exchanger 5 can be operated as a condenser to perform defrosting.

  Further, during the defrosting operation, a low-temperature and low-pressure refrigerant flows through the use side heat exchanger 3 and acts as an evaporator to absorb heat necessary for defrosting from water. At this time, hot water having a sufficient amount of heat for defrosting is allowed to flow from the hot water storage tank 6 into the use side heat exchanger 3, so that the hot water in the upper part of the hot water storage tank 6 coming from the upper pipe 19 by the first three-way valve 8 The low temperature water in the lower part of the hot water storage tank 6 coming from the lower pipe 20 is mixed.

  The hot water flowing into the use side heat exchanger 3 becomes low-temperature water in the use side heat exchanger 3, passes through the second water pipe 22, the second three-way valve 9, and the third water pipe 24 to store the hot water. 6 is returned to the bottom. Thus, by setting the return port of the cold water to the lower part of the hot water storage tank 6, it becomes possible to return water into the tank without breaking the temperature stratification, and the hot water at the upper part of the hot water storage tank 6 and the hot water at the lower part of the hot water storage tank 6. There is an effect that the mixing of is reduced.

  Drawing 5 is a figure for explaining an example of the flow of water at the time of defrosting operation. As shown in this figure, when the temperature of the water returning to the lower part of the hot water storage tank 6 is intermediate and higher than the temperature of the water (city water) supplied to the lower part of the hot water storage tank 6, as shown in FIG. Therefore, the temperature stratification in the hot water storage tank 6 is disturbed, the hot water in the upper part of the hot water storage tank 6 and the cold water in the lower part are mixed, and the amount of hot water that can be used for hot water supply decreases.

  Moreover, the temperature of the water returning to the lower part of the hot water storage tank 6 is higher than the temperature of the water (city water) supplied to the lower part of the tank, which means that a large amount of hot water is required to obtain the amount of heat necessary for defrosting. This means that the amount of hot water that can be used for hot water supply is reduced. That is, it is better to reduce the amount of hot water used by lowering the temperature of hot water flowing to the use side heat exchanger 3 so that the temperature of the water returning to the lower part of the hot water storage tank 6 is as low as possible.

However, if the temperature of the hot water flowing through the use side heat exchanger 3 is too low, there is a problem that the defrosting operation becomes long. Further, the amount of heat Qh heated by the use side heat exchanger 3 is defined by the flow rate of water Vw (l / s), the specific heat C of water (kJ / kg), and the temperature of water flowing into the use side heat exchanger 3 as Tin. When the temperature of the flowing hot water is Tout, it is expressed by the following equation.
Qh = Vw × C × (Tout-Tin) (1)

  As can be seen from the above equation (1), when the temperature of the water returning to the lower part of the hot water storage tank 6 is lower than the temperature of the water (city water) supplied to the upper part of the hot water storage tank 6, During the heating operation, the heating amount when heating to the predetermined temperature by the use side heat exchanger 3 is increased, and the power consumption is increased.

  Therefore, in the heat pump of the present embodiment, the second temperature detection means 11 is provided in a pipe for supplying city water, and the temperature of the first temperature detection means 10 provided in the third water pipe 24 is the second temperature. The amount of hot and cold water mixed in the first three-way valve 8 is determined so as to be the same as the detection value of the detection means 11. Thus, by adjusting the temperature of the water returning to the hot water storage tank 6, the hot water inside the tank can be used effectively, and a heat source having sufficient heat for defrosting can be provided. it can.

  Next, the operation of each actuator will be specifically described with reference to a flowchart. FIG. 6 is a flowchart of a routine in which the heat pump water heater of the first embodiment performs a defrosting operation. The routine shown in FIG. 6 is executed when it is determined that the heating capacity has decreased due to frost formation on the heat source side heat exchanger 5.

  In the routine shown in FIG. 6, first, in step S1, the compressor 1 is stopped or the compressor frequency is lowered to an arbitrary frequency. However, if the four-way valve 2 can be switched, the compressor frequency may be left as it is.

  In the next step S2, the four-way valve 2 is switched to reverse the refrigerant flow, and the expansion valve 4 is fully opened. As described above, the defrosting time can be further shortened by reducing the resistance of the expansion valve portion and increasing the flow rate of the refrigerant.

  In the next step S3, the compressor frequency is set to a predetermined compressor frequency during the defrosting operation. In the next step S4, the detection value Tw1 of the first temperature detection means 10 is compared with the detection value Tw2 of the second temperature detection means 11. As a result, when Tw1 = Tw2, the process proceeds to the next step S6 to determine the end of the defrosting operation. On the other hand, if Tw1 ≠ Tw2 in step S4, the process proceeds to the next step S5, and the first three-way valve 8 is adjusted. Here, specifically, for example, when Tw1> Tw2, the first three-way valve 8 is adjusted so that the amount of low-temperature water from the lower part of the hot water storage tank 6 is increased, and when Tw1 <Tw2 The first three-way valve 8 is adjusted so that the amount of hot water from the upper part of the hot water storage tank 6 is increased.

  When the process of step S5 is completed, the process proceeds to step S6 described above. In step S6, it is determined whether or not the defrosting is finished. If the defrosting is not finished yet, the process returns to step S4 again to compare Tw1 and Tw2. This operation is performed until the defrosting operation is completed. In the routine shown in FIG. 6, Tw1 = Tw2 is set. However, Tw1 = Tw2 + α, and the temperature returning to the hot water storage tank 6 may be higher than the city water temperature.

  As described above, by adjusting the temperature of the hot water supplied to the use-side heat exchanger 3 during the defrosting operation, it is possible to suppress a decrease in the amount of hot water in the hot water storage tank 6 to prevent the hot water from running out during hot water supply, and during the heating operation. Reheating of hot water when returning is avoided. Further, as described above, it is possible to perform defrosting operation at high speed and high efficiency by effectively removing heat necessary for defrosting from hot water.

  In addition, during the defrosting operation, the refrigerant saturation temperature of the use side heat exchanger 3 acting as an evaporator becomes 0 ° C. or less, and there may be a problem that water inside the use side heat exchanger freezes. As in the present invention, the temperature of the water coming out of the use side heat exchanger 3 and returning to the hot water storage tank 6 is adjusted to be the city water temperature (higher than 0 ° C.) or the temperature at the lower part of the hot water storage tank 6. There is also an effect that it is possible to avoid problems such as freezing of the water, blocking of the water flow path, and rupture of the water flow path.

  By the way, in the heat pump hot-water supply apparatus of Embodiment 1 mentioned above, although the expansion valve 4 was opened fully at the time of a defrost operation, it is good also as respond | corresponding, for example with the structure shown below. FIG. 7 is a diagram illustrating a modification of the heat pump hot water supply apparatus according to the first embodiment. As shown in this figure, a bypass circuit 41 that bypasses the expansion valve 4 and an on-off valve 42 disposed in the middle of the bypass circuit 41 are provided, and the on-off valve 42 is controlled to be closed during the heating operation, During the defrosting operation, the on-off valve 42 may be controlled to open.

  In the heat pump hot water supply apparatus of the first embodiment described above, the detection value Tw2 of the second temperature detection means 11 provided in the middle of the pipe 12 for supplying city water to the lower part of the hot water storage tank 6 and the first temperature detection. Although the detection value Tw1 of the means 10 is compared, the temperature to be compared is not limited to this. FIG. 8 is a diagram illustrating a modification of the heat pump hot water supply apparatus according to the first embodiment. As shown in this figure, instead of the second temperature detection means 11, a third temperature detection means 14 is provided so that the water temperature at the lower part of the hot water storage tank 6 can be detected, and a third water pipe 24 is provided with a third temperature detection means 14. The opening degree of the first three-way valve 8 may be determined so that the detection value Tw1 of the first temperature detection means 10 is the same as the detection value of the third temperature detection means 14.

  In the heat pump hot water supply apparatus of the first embodiment described above, the first three-way valve 8 is connected to the upper pipe 19, but is connected to the middle part of the hot water storage tank 6 so as to take out the warm water in the hot water storage tank 6. Alternatively, it may be connected to the middle pipe 23. FIG. 9 is a diagram illustrating a modification of the heat pump hot water supply apparatus according to the first embodiment. As shown in this figure, by reducing the middle temperature water in the central portion of the hot water storage tank 6, it becomes easier to generate temperature stratification, and mixing of hot hot water at the upper part of the hot water storage tank 6 and lower temperature hot water at the lower part is reduced. There is also an effect.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG. 10 and FIG. FIG. 10 is a diagram illustrating a schematic configuration of the heat pump hot water supply apparatus according to Embodiment 2 of the present invention. As shown in FIG. 10, in the heat pump hot water supply apparatus of the present embodiment, the fourth temperature detection means 15 and the fifth temperature detection means 16 are respectively arranged before and after the use side heat exchanger 3 in the refrigerant pipe 13. Except for this point, the heat pump hot water supply apparatus shown in FIG. The fourth temperature detection means 15 detects the temperature of the refrigerant entering the use side heat exchanger 3 during the defrosting operation, and the fifth temperature detection means 15 detects the refrigerant coming out of the use side heat exchanger 3 during the defrosting operation. Detect the temperature.

  In the heat pump hot water supply apparatus shown in FIG. 10, it is possible to provide a heat pump apparatus with further improved reliability by adding the above-described temperature detection means. That is, during the defrosting operation, the refrigerant introduced into the use-side heat exchanger 3 may not evaporate, and there may be a problem that the refrigerant is returned to the compressor 1 and liquid-compressed in a two-phase state containing liquid refrigerant. . Therefore, the detection value Tw4 of the fourth temperature detection means 15 shown in FIG. 10 is compared with the detection value Tw5 of the fifth temperature detection means 16, and if Tw5 <Tw4, it is determined that the evaporation has not been completed. The compressor frequency is lowered and the refrigerant flow rate is reduced.

  Next, specific processing according to the second embodiment will be described with reference to a flowchart. FIG. 11 is a flowchart of a routine in which the heat pump water heater of the second embodiment executes a defrosting operation. In the routine shown in FIG. 11, steps S1 to S5 are the same as the routine shown in FIG.

  In step S6, Tw5 and Tw4 are compared. As a result, when Tw5 <Tw4, it is determined that the refrigerant has not completely evaporated and the liquid refrigerant is flowing into the compressor 1 (liquid backed), and the compressor frequency is set in the next step S7. Decrease by a predetermined amount. Thereafter, in step S8, it is determined whether or not the defrosting is finished. If the defrosting is not finished yet, the same operation is repeated from step S4.

  In this way, by adjusting the refrigerant flow rate so that the refrigerant returning to the compressor 1 is always in a gas state, it is possible to avoid liquid compression and improve the reliability of the heat pump water heater. Further, an increase in power consumption due to liquid compression can be avoided.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIG. 12 and FIG. FIG. 12 is a diagram showing a schematic configuration of a heat pump hot water supply apparatus according to Embodiment 3 of the present invention. As shown in FIG. 12, the heat pump water heater of this embodiment is the same as the heat pump water heater shown in FIG. 1 except that the fourth water pipe 25 is drained without being connected to the lower part of the hot water storage tank 6. It is configured.

  In the third embodiment, there is no need to worry about the water temperature returned to the hot water storage tank 6, and the second temperature detection means 11 provided in the fourth water pipe 25 is made as low as possible. However, as described in the first embodiment, the first three-way valve 8 is adjusted so that the temperature of the first temperature detecting means 10 becomes 0 ° C. in order to avoid freezing of the use side heat exchanger 3. I decided to.

  Next, specific processing of the third embodiment will be described with reference to a flowchart. FIG. 13 is a flowchart of a routine in which the heat pump water heater of the third embodiment performs a defrosting operation. In the routine shown in FIG. 13, steps S1 to S3 are the same as the routine shown in FIG.

  In step S4, it is determined whether or not the detected value Tw1 of the first temperature detecting means 10 is equal to 0 ° C. As a result, when Tw1 ≠ 0 ° C., the process proceeds to the next step S5, and the first three-way valve 8 is adjusted. Specifically, when Tw1> 0 ° C., the first three-way valve 8 is adjusted so that the amount of low-temperature water from the lower part of the hot water storage tank 6 is increased, and when Tw1 <0 ° C. The first three-way valve 8 is adjusted so that the amount of hot water from the hot water storage tank 6 is increased.

  When Tw1 ≠ 0 ° C. in Step S4, or after adjusting the opening degree of the first three-way valve 8 in Step S5, the process proceeds to the next Step S6. In step S6, it is determined whether or not the defrosting is completed. If the defrosting is not yet completed, the process returns to step S4 again to determine whether or not Tw1 is equal to 0 ° C. This operation is performed until the defrosting operation is completed. In the routine shown in FIG. 13, Tw1 = 0 ° C., but Tw1 = 0 ° C. + α, and the temperature of Tw1 may be higher than 0 ° C.

  As described above, by adjusting the temperature of hot water supplied to the use-side heat exchanger 3 during the defrosting operation, it is possible to suppress a decrease in the amount of hot water in the hot water storage tank 6 and prevent hot water from running out during hot water supply. Further, by draining the cold water, it becomes possible to suppress the temperature drop of the water in the lower part of the hot water storage tank 6, and the reheating of the hot water when returning to the heating operation can be avoided. Further, as described above, it is possible to perform defrosting operation at high speed and high efficiency by effectively removing heat necessary for defrosting from hot water.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Use side heat exchanger 4 Expansion valve 5 Heat source side heat exchanger 6 Hot water storage tank 7 Water pump 8 First three-way valve (mixing valve)
9 Second three-way valve (flow path switching means, second flow path switching means)
10 first temperature detection means 11 second temperature detection means 12 pipe 13 refrigerant pipe 14 third temperature detection means 15 fourth temperature detection means 16 fifth temperature detection means 19 upper pipe 20 lower pipe 21 first Water pipe 22 Second water pipe 24 Third water pipe 25 Fourth water pipe 41 Bypass circuit (bypass pipe)
42 On-off valve 100 Heat pump unit 200 Tank unit

Claims (9)

A compressor for compressing the refrigerant, a use side heat exchanger for heating water with the refrigerant compressed by the compressor, an expansion valve, and a heat source side heat exchanger are connected in this order by the refrigerant flow path. A refrigeration cycle circuit;
A hot water storage tank, a first water pipe having one end connected to the water inlet of the use side heat exchanger, a water pump provided in the middle of the first water pipe, and the use side heat exchanger A second water pipe connecting a water outlet and an upper part of the hot water storage tank, a mixing valve disposed at the other end of the first water pipe, and connecting the mixing valve and the lower part of the hot water storage tank A hot water supply circuit having a lower pipe, and an upper pipe connecting the upper part of the mixing valve and the lower pipe in the hot water storage tank.
Control means for controlling the refrigeration cycle circuit and the hot water supply circuit,
The mixing valve is configured to be able to adjust the ratio of the amount of water flowing through the lower pipe and the amount of water flowing through the upper pipe,
The control means controls the mixing valve to control the temperature of the water flowing into the use side heat exchanger during the defrosting operation in which the refrigerant flowing through the refrigeration cycle circuit is caused to flow backward to defrost the heat source side heat exchanger. Adjust heat pump water heater. A third water pipe branched from the middle of the second water pipe and connected to the lower part of the hot water storage tank;
A flow path switching means provided at a branch point between the second water pipe and the third water pipe,
The flow path switching means can be switched between a state in which the water outlet of the use side heat exchanger is communicated with the upper part of the hot water storage tank and a state in which the outlet of the hot water storage tank is communicated with
2. The heat pump hot water supply apparatus according to claim 1, wherein the control means switches the flow path switching means to a state in which an outlet of water of the use side heat exchanger communicates with a lower portion of the hot water storage tank during the defrosting operation. First temperature detecting means for detecting the temperature of circulating water circulated from the third water pipe to the lower part of the hot water storage tank;
City water supply means for supplying city water to the lower part of the hot water storage tank;
A second temperature detecting means for detecting the temperature of the city water,
The heat pump hot water supply apparatus according to claim 2, wherein the control means controls the opening of the mixing valve so that the temperature of the circulating water becomes equal to the temperature of the city water. First temperature detecting means for detecting the temperature of circulating water circulated from the third water pipe to the lower part of the hot water storage tank;
A third temperature detecting means for detecting the temperature of the lower stored water stored in the lower part of the hot water storage tank;
The heat pump hot water supply apparatus according to claim 2, wherein the control means controls the opening of the mixing valve so that the temperature of the circulating water becomes equal to the temperature of the lower reservoir water.   The heat pump hot water supply apparatus according to any one of claims 1 to 4, wherein the control means opens the expansion valve fully open during the defrosting operation. A bypass pipe for bypassing the expansion valve from the refrigerant flow path;
An on-off valve for opening and closing the bypass pipe,
The heat pump hot water supply apparatus according to any one of claims 1 to 4, wherein the control means opens the on-off valve during the defrosting operation. A first temperature detecting means for detecting the temperature of circulating water circulated from the third water pipe to the lower part of the hot water storage tank;
The heat pump hot water supply apparatus according to any one of claims 1 to 6, wherein the control means controls the three-way valve so that a temperature of the circulating water becomes 0 ° C or higher during the defrosting operation. A fourth temperature detecting means for detecting a refrigerant temperature at an inlet of the refrigerant of the use side heat exchanger;
Fifth temperature detecting means for detecting the refrigerant temperature at the refrigerant outlet of the use side heat exchanger;
Further comprising
In the defrosting operation, when the refrigerant temperature detected by the fourth temperature detection unit is higher than the refrigerant temperature detected by the fifth temperature detection unit, the control unit rotates the compressor. The heat pump hot-water supply apparatus of any one of Claims 1 thru | or 7 which reduces this. A fourth water pipe that branches off from the middle of the second water pipe and communicates with the outside;
A second flow path switching means provided at a branch point between the second water pipe and the fourth water pipe;
The second flow path switching means switches between a state in which the water outlet of the use side heat exchanger communicates with an upper portion of the hot water storage tank and a state in which the water outlet communicates with the outside through the fourth water pipe. Is possible,
The heat pump hot water supply apparatus according to claim 1, wherein the control means switches the second flow path switching means to a state in which an outlet of water of the use side heat exchanger is communicated to the outside during the defrosting operation.

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