JPH10227536A - Heat pump hot-water supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable heat pump hot-water supply, with which the switching noise of a refrigerant circuit is prevented, the stopping of a compressor is not necessary, the quick cooling performance of air conditioning is improved and the delay of the start up time of the hot-water supply is prevented at the switching from a refrigerating run to a refrigerating/hot-water supply run. SOLUTION: The heat pump hot water supply is provided with a refrigerant circuit being connected toroidally to a compressor 11, an outdoor heat exchanger 13, an electric motor operated expansion valve EV2 and an indoor heat exchanger 14. An end of a hot-water heat exchanger, 15 is connected on the discharging side of the compressor 11 and the other end of the hot-water heat exchanger 15 is connected to a refrigerant piping 32 between the outdoor heat exchanger 13 and the valve EV2 through an electric motor operated expansion valve EV3. At the air conditioning run stopping the hot-water supply run, the opening of the valve EV3 is decreased and the pressure inside the refrigerant circuit on the side of the hot-water heat exchanger 15 is turned to high pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat pump water heater having a cooling function and a hot water supply function.

[0002]

2. Description of the Related Art Conventionally, as a heat pump water heater, as shown in FIG.
And a hot water storage tank unit 30 for performing a cooling / heating operation and a hot water supply operation. This heat pump water heater is configured by connecting the compressor 11, the four-way valve 12, the outdoor heat exchanger 13, and the electric expansion valves EV1, EV2 of the outdoor unit 10 and the indoor heat exchanger 14 of the indoor unit 20 in a ring shape. The refrigerant circuit. An electromagnetic valve 21 is disposed in a refrigerant pipe 31 between the compressor 11 and the four-way valve 12, and a refrigerant pipe 32 between the electric expansion valve EV1 and the electric expansion valve EV2.
, A closing valve 23 is provided in a refrigerant pipe 33 between the indoor heat exchanger 14 and the four-way valve 12.

The refrigerant pipe 3 of the outdoor unit 10
2, one end of the capillary tube 43 is connected via check valves 41 and 42 that allow only the flow from the capillary tube 43 side to the closing valve 22 side. The other end of the capillary tube 43 is connected to one end of a hot water supply heat exchanger 15 having a double pipe structure of the hot water storage tank unit 30. The other end of the hot water supply heat exchanger 15 is connected to the compressor 11 of the outdoor unit 10.
Is connected by a refrigerant pipe 34, and a closing valve 24 and a solenoid valve 25 are disposed on the refrigerant pipe 34 in order from the hot water supply heat exchanger 15 side. Then, the upstream side of the accumulator 17 is connected to a refrigerant pipe 34 between the closing valve 24 and the solenoid valve 25 of the outdoor unit 10 by a refrigerant pipe 35,
An electromagnetic valve 26 is provided in the refrigerant pipe 35.

In the heat pump water heater having the above configuration, when only the cooling operation is performed with the hot water supply operation stopped, the electromagnetic valves 21 and 26 are opened, the electromagnetic valve 25 is closed, and the electric expansion valve EV1 is fully opened. And the electric expansion valve EV2
To a predetermined opening. Then, the refrigerant discharged from the compressor 11 circulates in the order of the outdoor heat exchanger 13, the electric expansion valve EV1, the electric expansion valve EV2, the indoor heat exchanger 14, and the accumulator 17, and the refrigerant is circulated in the outdoor heat exchanger 13. The cooling operation is performed by condensing the refrigerant and evaporating the refrigerant in the indoor heat exchanger 14. At this time, no refrigerant flows through the hot water supply heat exchanger 15 of the hot water storage tank unit 30, and the capillary tube 4
The refrigerant circuit on the hot water supply heat exchanger 15 side from 3 to the electromagnetic valve 26 is connected to the low pressure side via the electromagnetic valve 26 to reduce the pressure inside the refrigerant circuit on the hot water supply heat exchanger 15 side. Then, when the remaining hot water in the hot water storage tank 16 of the hot water storage tank unit 30 decreases due to tapping during the cooling operation and the hot water supply operation is started, the electromagnetic valve 21 is closed, the electric expansion valve EV1 is fully closed, and the electromagnetic operation is started. The solenoid valve 25 is opened while the valve 26 is closed. Then, the refrigerant discharged from the compressor 11 is supplied to the hot water supply heat exchanger 15, the capillary tube 43, the check valve 42,
The check valve 41, the electric expansion valve EV2, the indoor heat exchanger 14, and the accumulator 17 circulate in this order, and the hot water supply heat exchanger 15
To condense the refrigerant and boil the hot water in the hot water storage tank 16,
The cooling operation is performed by evaporating the refrigerant in the indoor heat exchanger 14.

[0005]

In the heat pump water heater, when the hot water supply operation is started during the cooling operation, since the pressure in the refrigerant circuit on the side of the hot water storage tank unit 30 is low, noise is generated when the refrigerant circuit is switched. In addition to this, a downtime for stopping the compressor 11 for equalizing pressure and the like is required, so that the quick cooling of the cooling is impaired and the rise of hot water supply is delayed. When performing the cooling operation in a state where the hot water supply operation is stopped, the check valves 41 and 42 are used.
When the high-pressure refrigerant leaks from the hot water supply heat exchanger 15 into the hot water supply heat exchanger 15, the water in the double pipe structure hot water supply heat exchanger 15 freezes and expands, and the hot water supply heat exchanger 15 may be ruptured.

Therefore, an object of the present invention is to prevent the generation of switching noise of the refrigerant circuit when switching from the cooling operation to the cooling / hot water supply operation, and to improve the rapid cooling of the cooling without stopping the compressor. An object of the present invention is to provide a highly reliable heat pump water heater capable of preventing a delay in rising of hot water.

[0007]

According to a first aspect of the present invention, there is provided a heat pump water heater, comprising: a refrigerant circuit in which a compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger are connected in a ring; A hot water supply heat exchanger having one end connected to the discharge side of the compressor, and one end connected to the other end of the hot water supply heat exchanger, and the other end connected to a refrigerant pipe between the outdoor heat exchanger and the decompressor. And an electric expansion valve connected to the motor.

According to the heat pump water heater of the first aspect, when performing the cooling operation while the hot water supply operation is stopped,
By narrowing the opening of the electric expansion valve, the refrigerant circuit on the hot water supply heat exchanger side from the electric expansion valve to the discharge side of the compressor has a high pressure. When the hot water supply operation is started during the cooling operation, since the pressure in the refrigerant circuit on the side of the hot water supply heat exchanger is high, it is not necessary to stop the compressor. Open and circulate the refrigerant in the order of compressor, hot water supply heat exchanger, electric expansion valve, decompressor and indoor heat exchanger. By doing so, the refrigerant is condensed in the hot water supply heat exchanger to perform heat exchange for boiling water, and the refrigerant is evaporated in the indoor heat exchanger to exchange heat with indoor air to perform a cooling operation. . Therefore, when switching from the cooling operation state to the cooling / hot water supply operation for performing both cooling and hot water supply, it is possible to prevent the generation of the switching noise of the refrigerant circuit, and it is not necessary to stop the compressor. It is possible to improve and prevent a delay in rising of hot water supply. Also,
The number of times of starting / stopping the compressor is reduced, and the possibility of freezing of the hot water supply heat exchanger is eliminated, so that the reliability can be improved.

The heat pump water heater according to claim 2 is
In the heat pump water heater of the first aspect, when performing the cooling operation in a state where the hot water supply operation is stopped, the refrigerant temperature at the outlet side of the outdoor heat exchanger is substantially equal to the refrigerant temperature at the outlet side of the hot water supply heat exchanger. Thus, a control device for controlling the opening degree of the electric expansion valve is provided.

According to the heat pump water heater of the second aspect, during the cooling operation while the hot water supply operation is stopped, the refrigerant temperature at the outlet side of the hot water supply heat exchanger is substantially equal to the refrigerant temperature at the outlet side of the outdoor heat exchanger. By adjusting the opening of the electric expansion valve, at the junction where the downstream side of the electric expansion valve is connected to the refrigerant pipe between the outlet side of the outdoor heat exchanger and the pressure reducer,
The state of supercooling of the refrigerant from the outdoor heat exchanger and that of the refrigerant from the hot water supply heat exchanger are made substantially the same. Therefore, the temperature of the refrigerant at the outlet side of the outdoor heat exchanger does not rise due to the refrigerant flowing in from the hot water supply heat exchanger side, and a decrease in the cooling capacity can be prevented.

The heat pump water heater according to claim 3 is
The heat pump water heater according to claim 2, wherein a first temperature sensor for detecting a refrigerant temperature on an outlet side of the outdoor heat exchanger,
A second temperature sensor for detecting a refrigerant temperature at an outlet side of the hot water supply heat exchanger, wherein the control device is configured to control a temperature of the refrigerant at an outlet side of the hot water supply heat exchanger detected by the second temperature sensor. The temperature of the refrigerant at the outlet of the outdoor heat exchanger is higher than the refrigerant temperature at the outlet of the outdoor heat exchanger detected by the first temperature sensor, and the temperature of the refrigerant at the outlet of the hot water supply heat exchanger is the same as the temperature of the refrigerant at the outlet of the outdoor heat exchanger. A first temperature determination unit that determines whether the temperature difference is higher than a first predetermined temperature; and a refrigerant temperature at an outlet side of the hot water supply heat exchanger detected by the second temperature sensor is determined by the first temperature sensor. The temperature difference between the detected refrigerant temperature at the outlet side of the outdoor heat exchanger and the refrigerant temperature at the outlet side of the hot water supply heat exchanger and the refrigerant temperature at the outlet side of the outdoor heat exchanger is the second. A second temperature determination for determining whether the temperature is lower than a predetermined temperature; Portion, the refrigerant temperature at the outlet side of the hot water supply heat exchanger is higher than the refrigerant temperature at the outlet side of the outdoor heat exchanger, and the refrigerant temperature at the outlet side of the hot water supply heat exchanger and the temperature of the outdoor heat exchanger. When the first temperature determining unit determines that the temperature difference from the refrigerant temperature on the outlet side is higher than a first predetermined temperature,
While the opening degree of the electric expansion valve is reduced, the refrigerant temperature on the outlet side of the hot water supply heat exchanger is lower than the refrigerant temperature on the outlet side of the outdoor heat exchanger, and the outlet side of the hot water supply heat exchanger. When the second temperature discriminator determines that the temperature difference between the refrigerant temperature and the refrigerant temperature on the outlet side of the outdoor heat exchanger is lower than a second predetermined temperature, the electric expansion valve increases the opening of the electric expansion valve. And a control unit.

[0012] According to the heat pump water heater of the third aspect, the first temperature discriminator determines that the refrigerant temperature at the outlet side of the hot water heat exchanger is higher than the refrigerant temperature at the outlet side of the outdoor heat exchanger. When it is determined that the temperature difference between the refrigerant temperature on the outlet side of the hot water supply heat exchanger and the refrigerant temperature on the outlet side of the outdoor heat exchanger is higher than the first predetermined temperature, the electric expansion valve control unit determines the opening degree of the electric expansion valve. The refrigerant flow from the hot water supply heat exchanger side to the outlet side of the outdoor heat exchanger through the electric expansion valve,
The temperature of the refrigerant at the outlet of the hot water supply heat exchanger is reduced. on the other hand,
The second temperature determination unit is configured such that the refrigerant temperature at the outlet side of the hot water supply heat exchanger is lower than the refrigerant temperature at the outlet side of the outdoor heat exchanger, and
When determining that the temperature difference between the refrigerant temperature on the outlet side of the hot water supply heat exchanger and the refrigerant temperature on the outlet side of the outdoor heat exchanger is lower than the second predetermined temperature, the electric expansion valve control unit opens the electric expansion valve. The temperature of the refrigerant at the outlet side of the hot water supply heat exchanger is increased by increasing the refrigerant flow rate from the hot water supply heat exchanger side to the outlet side of the outdoor heat exchanger through the electric expansion valve. Therefore, by the simple control of the electric expansion valve, the refrigerant temperature on the outlet side of the outdoor heat exchanger can be made substantially equal to the refrigerant temperature on the outlet side of the hot water supply heat exchanger.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a heat pump water heater according to the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a circuit diagram of a heat pump water heater according to one embodiment of the present invention. The heat pump water heater includes an outdoor unit 1, an indoor unit 2, and a hot water storage tank unit 3. The outdoor unit 1 includes a compressor 11, a four-way valve 12 connected to the discharge side of the compressor 11, an outdoor heat exchanger 13 having one end connected to the four-way valve 12, and an outdoor heat exchanger. An electric expansion valve EV1 having one end connected to the other end of the vessel 13. One end of an electric expansion valve EV2 is connected to the other end of the electric expansion valve EV1 via a closing valve 22. The other end of the electric expansion valve EV2 of the outdoor unit 1 and the indoor heat exchanger 1 of the indoor unit 2
4 is connected to one end. The other end of the indoor heat exchanger 14 of the indoor unit 2 is connected to the suction side of the compressor 11 via the four-way valve 12 and the accumulator 17 of the outdoor unit 1. In addition, an electromagnetic valve 21 is provided in a refrigerant pipe 31 between the compressor 11 and the four-way valve 12, and a refrigerant pipe 3 between the indoor heat exchanger 14 of the indoor unit 2 and the four-way valve 12 is provided.
3 is provided with a closing valve 23.

Further, the closing valve 22 and the electric expansion valve EV2
One end of the electric expansion valve EV3 is connected to the refrigerant pipe 32 between the two, and the other end of the electric expansion valve EV3 is connected to one end of the hot water supply heat exchanger 15 of the double pipe structure of the hot water storage tank unit 3. The upper end of the inner pipe of the hot water supply heat exchanger 15 is
6, the lower end of the inner pipe of the hot water supply heat exchanger 15 is connected to the bottom of the hot water storage tank 16. The hot water in the hot water storage tank 16 is stored in the hot water storage tank 16 and the hot water supply heat exchanger 15.
The water is circulated in the inner pipe by the pump 18 and heat is exchanged in the hot water supply heat exchanger 15 to boil the hot water. The hot water supply heat exchanger 1
The other end of 5 is connected to the discharge side of the compressor 11 by a refrigerant pipe 34, and a closing valve 24 and a solenoid valve 25 are arranged in the refrigerant pipe 34 in order from the hot water supply heat exchanger 15 side. The upstream side of the accumulator 17 is connected to a refrigerant pipe 34 between the closing valve 24 and the solenoid valve 25 by a refrigerant pipe 35, and the solenoid valve 26 is disposed in the refrigerant pipe 35.

Further, the heat pump water heater has a thermistor 51 as a first temperature sensor for detecting a refrigerant temperature at an outlet side of the outdoor heat exchanger 13 and detects a refrigerant temperature at an outlet side of the hot water supply heat exchanger 15. A thermistor 52 as a second temperature sensor is provided. The heat pump water heater receives the output signals of the thermistors 51 and 52,
A control device 50 for controlling the compressor 11, the electric expansion valves EV1 to EV3, and the like is provided. The control device 50 includes a microcomputer, an input / output circuit, and the like. The refrigerant temperature at the outlet side of the hot water supply heat exchanger 15 detected by the thermistor 52 is at the outlet side of the outdoor heat exchanger 13 detected by the thermistor 51. It is determined whether the temperature is higher than the refrigerant temperature and the temperature difference between the refrigerant temperature at the outlet side of the hot water supply heat exchanger 15 and the refrigerant temperature at the outlet side of the outdoor heat exchanger 13 is higher than a first predetermined temperature α. A first temperature discriminator 50a and an outdoor heat exchanger 1 in which the refrigerant temperature on the outlet side of the hot water supply heat exchanger 15 detected by the thermistor 52 is detected by the thermistor 51;
3 and a temperature difference between the refrigerant temperature on the outlet side of the hot water supply heat exchanger 15 and the refrigerant temperature on the outlet side of the outdoor heat exchanger 13 is lower than the second predetermined temperature -α. Electric expansion valve control for controlling the degree of opening of the electric expansion valve EV3 based on the judgment result of the second temperature judgment unit 50b for judging whether or not the temperature is high, and the judgment result of the first temperature judgment unit 50a and the second temperature judgment unit 50b. A portion 50c.

In the heat pump water heater of the above configuration, when the cooling operation is performed in a state where the hot water supply operation is stopped, as shown in FIG. 1, the electromagnetic valves 21 and 25 are opened, while the electromagnetic valve 26 is opened.
Is closed, the electric expansion valve EV1 is fully opened, and the electric expansion valve EV2 is set to a predetermined opening degree. And the compressor 11
Is circulated in the order of the outdoor heat exchanger 13, the electric expansion valve EV1, the electric expansion valve EV2, the indoor heat exchanger 14, and the accumulator 17. At this time, the opening degree of the electric expansion valve EV3 is controlled by the control device 50.

FIG. 2 shows the electric expansion valve EV of the control device 50.
6 is a flowchart illustrating an operation of an opening degree control 3;

The opening control process of the control device 50 will be described below with reference to FIG.

First, when the process starts, step S
In 1, the refrigerant temperature DLW on the outlet side of the hot water supply heat exchanger 15 detected by the thermistor 52 by the first temperature determination unit 50 a
It is determined whether the temperature difference (DLW-DEL) between the temperature and the refrigerant temperature DEL on the outlet side of the outdoor heat exchanger 13 detected by the thermistor 51 is higher than the first predetermined temperature α. And
If it is determined in step S1 that the temperature difference (DLW-DEL) is higher than the first predetermined temperature α, the process proceeds to step S4,
If it is determined that the temperature difference (DLW-DEL) is lower than or equal to the first predetermined temperature α, the process proceeds to step S2.

Next, in step S2, the first temperature discriminating section 50
The refrigerant temperature DLW on the outlet side of the hot water supply heat exchanger 15 detected by the thermistor 52 in accordance with a and the refrigerant temperature DEL on the outlet side of the outdoor heat exchanger 13 detected by the thermistor 51
It is determined whether or not the temperature difference (DLW-DEL) is lower than the second predetermined temperature −α. Then, in step S1, the temperature difference
If it is determined that (DLW-DEL) is lower than the second predetermined temperature -α, the process returns to step S1 while the temperature difference (DLW-DEL) is determined.
If it is determined that EL) is higher than or equal to the second predetermined temperature -α, the process proceeds to step S3.

Next, after the opening EVW of the electric expansion valve EV3 is increased by a predetermined opening β in step S3, the process returns to step S1.

On the other hand, after reducing the opening EVW of the electric expansion valve EV3 by a predetermined opening β in step S4, the process returns to step S1.

The predetermined opening β is obtained by β = │DEW-DEL│ × γ (γ: coefficient).

As described above, when the cooling operation is performed while the hot water supply operation is stopped, the electromagnetic valve 25 is opened, the electromagnetic valve 26 is closed, and the opening of the electric expansion valve EV3 is reduced, so that the electric expansion is performed. The pressure in the refrigerant circuit on the hot water supply heat exchanger 15 side from the valve EV3 to the solenoid valve 25 is increased. At this time, the temperature difference (DLW-DEL) between the refrigerant temperature DLW on the outlet side of the hot water supply heat exchanger 15 and the refrigerant temperature DEL on the outlet side of the outdoor heat exchanger 13 is determined by the control device 50 to be the predetermined temperature α.
If it is higher, the opening EVW of the electric expansion valve EV3 is reduced based on the absolute value of the temperature difference (DLW-DEL), and flows from the hot water supply heat exchanger 15 to the outlet of the outdoor heat exchanger 13. While reducing the flow rate of the refrigerant, the temperature difference (D
LW-DEL) is lower than the predetermined temperature -α, the electric expansion valve E is determined based on the absolute value of the temperature difference (DLW-DEL).
By increasing the opening EVW of V3, the flow rate of the refrigerant flowing from the hot water supply heat exchanger 15 side to the outlet side of the outdoor heat exchanger 13 is increased. Thus, the opening degree EVW of the electric expansion valve EV3 is obtained.
Is adjusted, the electric expansion valve E is connected to the refrigerant pipe 32 between the outlet side of the outdoor heat exchanger 13 and the electric expansion valve EV2.
At the junction A where the downstream side of V3 is connected, the state of supercooling of the refrigerant from the outdoor heat exchanger 13 and the state of the refrigerant from the hot water supply heat exchanger 15 are substantially the same. When the hot water supply operation is started during the cooling operation, the electric expansion valve EV1 is closed and the electric expansion valve EV3 is opened to a predetermined opening without stopping the compressor 11, so that the compressor 11, the hot water supply heat exchange. The refrigerant is circulated in the order of the heat exchanger 15, the electric expansion valve EV3, the electric expansion valve EV2, and the indoor heat exchanger 14, so that the hot water supply heat exchanger 1
Heat exchange is performed in step 5.

When the hot water supply operation is started during the cooling operation, as shown in FIG. 3, the electromagnetic valve 21 is closed while the opened electromagnetic valve 25 and the closed electromagnetic valve 26 are kept as they are, and the electric expansion valve EV1 is opened. Is fully closed, and the electric expansion valve EV3 is fully opened. Then, the refrigerant discharged from the compressor 11 circulates in the order of the hot water supply heat exchanger 15, the electric expansion valve EV3, the electric expansion valve EV2 indoor heat exchanger 14, and the accumulator 17, and circulates the refrigerant in the hot water supply heat exchanger 15. The condensed water is heated in the hot water storage tank 16 and the refrigerant is evaporated in the indoor heat exchanger 14 to cool the room. When the hot water in the hot water storage tank 16 rises to the target temperature, the electric expansion valve EV1 is fully opened, the opening degree of the electric expansion valve EV3 is reduced, and the solenoid valve 21 is opened to perform only the cooling operation. In addition,
When only the hot water supply operation is performed, the four-way valve 12 is switched to the switching position indicated by the dotted line, the electric expansion valve EV1 is fully opened, the electric expansion valve EV2 is fully closed, the electromagnetic valves 21 and 26 are closed, and the electromagnetic valve 25 is closed. Is opened, and the refrigerant discharged from the compressor 11 is circulated in the order of the hot water supply heat exchanger 15, the electric expansion valve EV3, the electric expansion valve EV1, and the outdoor heat exchanger 13.

Therefore, when the hot water supply operation is started during the cooling operation, the state of the refrigerant circuit on the hot water supply heat exchanger 15 side before switching from the cooling operation to the cooling / hot water supply operation is at a high pressure. Can be prevented from occurring, and the cooling speed of the cooling can be improved without stopping the compressor 11, and a delay in rising of hot water supply can be prevented. In addition, the number of times of starting / stopping of the compressor 11 is reduced, and there is no fear of breakage due to freezing of the hot water supply heat exchanger 15, so that reliability can be improved.

The controller 50 also controls the refrigerant temperature DLW on the outlet side of the hot water supply heat exchanger 15 to reduce the outdoor heat exchanger 1 temperature.
By controlling the opening degree EVW of the electric expansion valve EV3 by the control device 50 so as to be substantially equal to the refrigerant temperature DEL on the outlet side of the refrigerant pipe 3 at the junction A of the refrigerant pipe 32,
The state of supercooling of the refrigerant on the outdoor heat exchanger 13 side and the refrigerant on the hot water supply heat exchanger 15 side can be made substantially the same, and the refrigerant flowing in from the hot water supply heat exchanger 15 closes the outlet side of the outdoor heat exchanger 13. It is possible to prevent a decrease in cooling capacity without increasing the refrigerant temperature.

Further, by the simple control of the electric expansion valve EV3 by the control device 50, the refrigerant temperature DEL at the outlet of the outdoor heat exchanger 13 and the refrigerant temperature DLW at the outlet of the hot water supply heat exchanger 15 are made substantially equal. be able to.

In the above embodiment, when the cooling operation is performed with the hot water supply operation stopped, the refrigerant temperature at the outlet side of the outdoor heat exchanger 13 and the refrigerant temperature at the outlet side of the hot water supply heat exchanger 15 are substantially equal. Although the opening degree of the electric expansion valve EV3 is adjusted so as to be as described above, the opening degree adjustment of the electric expansion valve may be fixed.

In the above embodiment, the four-way valve 1
Although the heat pump water heater that performs the cooling and heating operation by switching 2 has been described, the present invention may be applied to a heat pump water heater that performs the cooling operation and the hot water supply operation without the four-way valve.

Further, in the above embodiment, the electric expansion valve EV2 whose opening can be adjusted is used as the decompressor, but a decompressor may be used.

[0033] The number of indoor units and the structure of the hot water supply heat exchanger in the heat pump water heater of the present invention are not limited to the above embodiment.

[0034]

As is apparent from the above description, the heat pump water heater according to the first aspect of the present invention comprises a refrigerant circuit in which a compressor, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger are connected in a ring.
A hot water supply heat exchanger having one end connected to the discharge side of the compressor, and one end connected to the other end of the hot water supply heat exchanger, and the other end connected to a refrigerant pipe between the outdoor heat exchanger and the decompressor. And an electric expansion valve connected to the motor.

Therefore, according to the heat pump water heater of the first aspect of the present invention, when performing the cooling operation in a state where the hot water supply operation is stopped, the opening degree of the electric expansion valve is reduced, and the opening of the electric expansion valve is reduced. By setting the refrigerant circuit on the hot water supply heat exchanger side up to the discharge side to a high pressure, it is possible to prevent generation of a switching noise of the refrigerant circuit when switching from the cooling operation state to the cooling / hot water supply operation for performing both cooling and hot water supply. At the same time, there is no need to stop the compressor, and the rapid cooling of the cooling can be improved, and a delay in rising of hot water supply can be prevented. In addition, the number of times the compressor is started / stopped is reduced, and there is no possibility of damage due to freezing of the hot water supply heat exchanger, so that high reliability can be obtained.

In the heat pump water heater according to the second aspect of the present invention, in the heat pump water heater according to the first aspect, when performing the cooling operation in a state where the hot water supply operation is stopped, the temperature of the refrigerant at the outlet side of the outdoor heat exchanger is reduced. Since the opening of the electric expansion valve is controlled by the control device so that the refrigerant temperature on the outlet side of the hot water supply heat exchanger becomes substantially equal, the refrigerant pipe between the outlet side of the outdoor heat exchanger and the pressure reducer is controlled. At the junction where the downstream side of the electric expansion valve is connected, the state of supercooling of the refrigerant from the outdoor heat exchanger side and the refrigerant from the hot water supply heat exchanger side is almost the same, and the outlet side of the outdoor heat exchanger is The refrigerant temperature does not rise due to the refrigerant flowing from the hot water supply heat exchanger side, and a decrease in the cooling capacity can be prevented.

According to a third aspect of the present invention, in the heat pump water heater of the second aspect, the refrigerant temperature at the outlet of the hot water supply heat exchanger detected by the second temperature sensor is detected by the first temperature sensor. The temperature difference between the refrigerant temperature at the outlet side of the hot water supply heat exchanger and the refrigerant temperature at the outlet side of the outdoor heat exchanger is higher than the first predetermined temperature. Is too high and the first
When the temperature determination unit determines, the electric expansion valve control unit reduces the opening degree of the electric expansion valve and reduces the flow rate of refrigerant flowing from the hot water supply heat exchanger side to the outlet side of the outdoor heat exchanger via the electric expansion valve. The temperature of the refrigerant at the outlet of the hot water supply heat exchanger is lowered, and the temperature of the refrigerant at the outlet of the hot water supply heat exchanger detected by the second temperature sensor is detected by the first temperature sensor. If the temperature difference between the refrigerant temperature on the outlet side of the hot water supply heat exchanger and the refrigerant temperature on the outlet side of the outdoor heat exchanger is lower than a second predetermined temperature, the second temperature of the control device is lower than the second predetermined temperature. When the temperature determination unit determines, the electric expansion valve control unit increases the opening degree of the electric expansion valve and increases the flow rate of the refrigerant flowing from the hot water supply heat exchanger side to the outlet side of the outdoor heat exchanger via the electric expansion valve. Then, the refrigerant temperature at the outlet side of the hot water supply heat exchanger is increased. Therefore, by the simple control of the electric expansion valve, the refrigerant temperature on the outlet side of the outdoor heat exchanger and the refrigerant temperature on the outlet side of the hot water supply heat exchanger can be made substantially equal.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a state of a heat pump water heater according to an embodiment of the present invention during a cooling operation.

FIG. 2 is a flowchart of a control device of the heat pump water heater.

FIG. 3 is a circuit diagram showing a state of the heat pump water heater during a cooling / hot water supply operation.

FIG. 4 is a circuit diagram of a conventional heat pump water heater.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outdoor unit, 2 ... Indoor unit, 3 ... Hot water supply tank unit, 11 ... Compressor, 12 ... Four-way valve, 13 ... Outdoor heat exchanger, 14 ... Indoor heat exchanger, 15 ... Hot water supply heat exchanger, 1
6 hot water supply tank, 17 accumulator, 21, 25, 2
6 solenoid valves, 50: control device, 51, 52: thermistor,
EV1, EV2, EV3: Electric expansion valves.

Claims (3)

[Claims] 1. A refrigerant circuit in which a compressor (11), an outdoor heat exchanger (13), a pressure reducer (EV2) and an indoor heat exchanger (14) are connected in a ring shape, and a discharge of the compressor (11). A hot water supply heat exchanger (15) having one end connected to the other side, one end connected to the other end of the hot water supply heat exchanger (15), and the other end connected to the outdoor heat exchanger (13) and the pressure reducer (EV2). And a motor-operated expansion valve (EV3) connected to the refrigerant pipe (32). 2. The heat pump water heater according to claim 1, wherein when performing the cooling operation in a state where the hot water supply operation is stopped, the temperature of the refrigerant at the outlet side of the outdoor heat exchanger and the hot water supply heat exchanger. A control device (50) for controlling the opening of the electric expansion valve (EV3) so that the refrigerant temperature on the outlet side of the item (15) becomes substantially equal.
A heat pump water heater comprising: 3. The heat pump water heater according to claim 2, wherein a first temperature sensor (51) for detecting a refrigerant temperature at an outlet side of the outdoor heat exchanger (13), and the hot water heat exchanger (15). A second temperature sensor (52) for detecting a refrigerant temperature on an outlet side of the hot water supply heat exchanger (15) detected by the second temperature sensor (52). The refrigerant temperature at the outlet side is the first temperature sensor
(51) is higher than the refrigerant temperature at the outlet side of the outdoor heat exchanger (13), and the hot water supply heat exchanger (1
A first temperature discriminator (50a) for discriminating whether or not a temperature difference between the refrigerant temperature on the outlet side of 5) and the refrigerant temperature on the outlet side of the outdoor heat exchanger (13) is higher than a first predetermined temperature; The refrigerant temperature at the outlet of the hot water supply heat exchanger (15) detected by the second temperature sensor (52) is equal to the first temperature sensor.
(51) is lower than the refrigerant temperature at the outlet side of the outdoor heat exchanger (13), and the hot water supply heat exchanger (1
A second temperature determination unit (50b) that determines whether a temperature difference between the refrigerant temperature on the outlet side of 5) and the refrigerant temperature on the outlet side of the outdoor heat exchanger (13) is lower than a second predetermined temperature. The refrigerant temperature at the outlet of the hot water supply heat exchanger (15) is higher than the refrigerant temperature at the outlet of the outdoor heat exchanger (13), and
If the temperature difference between the refrigerant temperature at the outlet side of the hot water supply heat exchanger (15) and the refrigerant temperature at the outlet side of the outdoor heat exchanger (13) is higher than a first predetermined temperature, the first temperature discrimination section (50a ) Is determined, the opening degree of the electric expansion valve (EV3) is reduced, while the refrigerant temperature at the outlet side of the hot water supply heat exchanger (15) is lower than the refrigerant temperature at the outlet side of the outdoor heat exchanger (13). And the temperature difference between the refrigerant temperature at the outlet of the hot water supply heat exchanger (15) and the refrigerant at the outlet of the outdoor heat exchanger (13) is lower than a second predetermined temperature. A heat pump water heater comprising an electric expansion valve control section (50c) for increasing the opening of the electric expansion valve (EV3) when the temperature judgment section (50b) judges.