JP2021156500A - Heat pump type hot water unit - Google Patents

Abstract

To provide a heat pump type hot water unit that suppresses freezing of a water heat exchanger.SOLUTION: A heat pump type hot water unit includes: a refrigerant circuit having a compressor (1), a water heat exchanger (2), an expansion mechanism (EV) and an air heat exchanger (3); a water circuit having a circulation pump (P) circulating water via the water heat exchanger (2); and a control section (10) controlling the refrigerant circuit and the circulation pump (P). The heat pump type hot water unit is configured to enable execution of a first freezing prevention operation for preventing freezing of the water heat exchanger (2) with water circulated in the water circuit by controlling the refrigerant circuit and the circulation pump (P) and a second freezing prevention operation for preventing freezing of the water heat exchanger (2) by operating the compressor (1) in the state where the amount of water circulating in the water circuit is smaller than that in the first freezing prevention operation.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a heat pump type hot water unit.

The conventional heat pump type hot water unit includes a heat pump unit including a compressor, a water refrigerant heat exchanger, a decompression means, a refrigerant circuit formed by connecting an evaporator, and a circulation pump, a hot water storage tank, and a control device. There is one (see Patent Document 1). In this heat pump type hot water unit, the control device drives a circulation pump to transport the water in the lower part of the hot water storage tank to the upper part of the hot water storage tank via the water refrigerant heat exchanger, thereby freezing the water in each pipe. It has an antifreeze operation mode that suppresses antifreeze.

Japanese Unexamined Patent Publication No. 2014-196849

The conventional heat pump type hot water unit has a problem that freezing of the water refrigerant heat exchanger cannot be suppressed when a sufficient amount of water circulation cannot be secured due to a failure of the circulation pump or the like.

The present disclosure proposes a heat pump type hot water unit that suppresses freezing of a water heat exchanger.

The heat pump type hot water unit of the present disclosure is
Refrigerant circuits with compressors, water heat exchangers, expansion mechanisms, and air heat exchangers,
A water circuit having a circulation pump that circulates water through the water heat exchanger,
It is equipped with a control unit that controls the refrigerant circuit and the circulation pump.
The first anti-freezing operation for preventing freezing of the water heat exchanger in a state where water is circulated in the water circuit, and the above in a state where the amount of water circulating in the water circuit is smaller than that in the first anti-freezing operation. It is characterized in that the second anti-freezing operation of operating the compressor to prevent the water heat exchanger from freezing can be performed.

According to the present disclosure, the control unit operates the compressor in a state where the amount of water circulating in the water circuit is smaller than that in the first antifreeze operation to prevent the water heat exchanger from freezing in the second antifreeze operation. Since it is configured to be feasible, even if the amount of water circulating in the water circuit cannot be sufficiently secured due to a failure of the circulation pump, etc., the water heat exchanger can be frozen by executing the second antifreeze operation. Can be suppressed.

In the heat pump type hot water unit according to one aspect of the present disclosure,
The control unit executes the second antifreeze operation when a poor circulation of water through the water heat exchanger occurs in the water circuit.

According to the present disclosure, when the water circulation failure occurs in the water circuit via the water heat exchanger, the second antifreeze operation is executed, so that the circulation pump cannot be operated due to a failure or the like. In addition, the second antifreeze operation can be appropriately executed.

In the heat pump type hot water unit according to one aspect of the present disclosure,
When the control unit starts the compressor when the inlet temperature or the outlet temperature of the water heat exchanger is lower than the predetermined first temperature in the first antifreeze operation, after the compressor is started. When the pressure of the refrigerant circulating in the refrigerant circuit is higher than the predetermined pressure, the second antifreeze operation is executed.

When a circulation failure occurs in the water circuit via the water heat exchanger, when the compressor is started in the first antifreeze operation, the heat exchange between the refrigerant and water in the water heat exchanger becomes insufficient. , The pressure in the refrigerant circuit rises. According to the present disclosure, the control unit executes the second antifreeze operation when the pressure of the refrigerant in the refrigerant circuit after starting the compressor in the first antifreeze operation is higher than a predetermined pressure, and thus circulates. The second antifreeze operation can be appropriately executed when the pump cannot be operated due to a failure or the like.

The heat pump type hot water unit according to one aspect of the present disclosure is
The operating frequency of the compressor in the second antifreeze operation is lower than the operating frequency of the compressor in the boiling operation of boiling water in the water circuit.

According to the present disclosure, since the operating frequency of the compressor in the second antifreezing operation is lower than the operating frequency of the compressor in the boiling operation, it is possible to suppress an excessive increase in the pressure of the refrigerant in the second antifreezing operation. can.

The heat pump type hot water unit according to one aspect of the present disclosure is
Equipped with a fan that supplies air to the above air heat exchanger
The control unit controls the fan so that the fan is driven in the second antifreeze operation.

According to the present disclosure, in the second antifreeze operation, since the fan that supplies air to the air heat exchanger is driven, it is possible to suppress an excessive increase in the pressure of the refrigerant.

In the heat pump type hot water unit according to one aspect of the present disclosure,
The control unit controls the refrigerant circuit so that the second antifreeze operation is terminated when the condensation temperature in the water heat exchanger is higher than the predetermined second temperature.

According to the present disclosure, the second antifreeze operation ends when the condensation temperature in the water heat exchanger becomes higher than the second temperature. Therefore, for example, by setting the second temperature lower than the boiling temperature, the second temperature is set. 2 It is possible to suppress an excessive increase in the pressure of the refrigerant in the antifreeze operation.

In the heat pump type hot water unit according to one aspect of the present disclosure, the control unit starts the second antifreeze operation when the discharge pipe temperature of the compressor is lower than the predetermined third temperature. Control the circuit.

According to the present disclosure, after the second antifreeze operation is once executed, the next second antifreeze operation is executed after the discharge pipe temperature raised by the second antifreeze operation becomes lower than the predetermined third temperature. It will be possible. As a result, for example, by setting the third temperature to a temperature at which the compressor is sufficiently cooled, the time from the first execution of the second antifreeze operation to the next execution of the second antifreeze operation is secured. Therefore, it is possible to prevent the second antifreeze operation from being frequently executed.

In the heat pump type hot water unit according to one aspect of the present disclosure, the expansion mechanism is an electric valve, and the opening degree of the expansion mechanism in the second antifreeze operation is boiling water in the water circuit. It is larger than the opening degree of the expansion mechanism in operation.

According to the present disclosure, the opening degree of the electric valve in the second antifreeze operation is larger than the opening degree of the expansion mechanism in the boiling operation for boiling water in the water circuit. It is possible to suppress an excessive increase in pressure.

The heat pump type hot water unit according to one aspect of the present disclosure is configured so that the second antifreeze operation can be performed again when a predetermined time has elapsed from the end of the second antifreeze operation.

According to the present disclosure, since the time from the execution of the second antifreeze operation to the next execution of the second antifreeze operation is secured, it is possible to prevent the second antifreeze operation from being frequently executed. can.

It is a block diagram of the heat pump type hot water unit which concerns on embodiment of this disclosure. It is a control block diagram of the heat pump type hot water unit which concerns on embodiment of this disclosure. It is a control flowchart of the antifreeze operation which concerns on embodiment of this disclosure.

Hereinafter, the heat pump type hot water unit according to the embodiment of the present disclosure will be described with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of a hot water supply device to which the heat pump type hot water unit according to the present disclosure is applied.

As shown in FIG. 1, this hot water supply device includes a heat pump unit 100 and a hot water storage unit 200.

The heat pump unit 100 includes a compressor 1, a water heat exchanger 2 having one end connected to the discharge side of the compressor 1, an electric expansion valve EV having one end connected to the other end of the water heat exchanger 2, and an electric motor. An outdoor heat exchanger 3 having one end connected to the other end of the expansion valve EV, and an accumulator 4 having one end connected to the other end of the outdoor heat exchanger 3 and the other end connected to the suction side of the compressor 1. Be prepared. An outdoor fan 6 is arranged in the vicinity of the outdoor heat exchanger 3. The water heat exchanger 2 is a double pipe heat exchanger composed of an outer pipe 2a and an inner pipe 2b inserted into the outer pipe 2a. The water heat exchanger is not limited to the double tube heat exchanger, but may be a plate type heat exchanger or the like. The outdoor heat exchanger 3 according to the present embodiment is an example of the air heat exchanger according to the present disclosure. The electric expansion valve EV according to the present embodiment is an example of the expansion mechanism according to the present disclosure.

The electric expansion valve EV according to the present embodiment is a pulse-driven electric expansion valve driven by a stepping motor (not shown). The opening degree of the electric expansion valve EV is adjusted between 0% and 100% (for example, corresponding to 0 pls to 470 pls).

The compressor 1, the water heat exchanger 2, the outdoor heat exchanger 3, the electric expansion valve EV, and the accumulator 4 constitute the refrigerant circuit according to the present disclosure.

A discharge pipe temperature sensor 11 is provided on the discharge side of the compressor 1. Further, an outdoor temperature sensor 12 for detecting the outdoor temperature is provided in the vicinity of the outdoor heat exchanger 3.

Further, in the heat pump unit 100, one end of the water inlet pipe L1 is connected to the water inlet of the water heat exchanger 2, and one end of the hot water outlet pipe L2 is connected to the outlet of the water heat exchanger 2. The water inlet temperature sensor 13 is provided in the water inlet pipe L1, and the hot water outlet temperature sensor 14 is provided in the hot water outlet pipe L2. A circulation pump P is arranged in the water inlet pipe L1. The circulation pump P is provided with a rotation speed sensor (not shown) for detecting the rotation speed of the circulation pump P and a flow rate sensor (not shown) for detecting the flow rate discharged by the circulation pump P.

Further, in the heat pump unit 100, a pressure sensor 15 for measuring the discharge pressure of the compressor 1 is provided on the discharge side of the compressor 1.

The heat pump unit 100 includes a control device 10 as an example of the control unit according to the present disclosure. The control device 10 may be provided on the hot water storage unit 200 side, or each of the heat pump unit 100 and the hot water storage unit 200 may be provided with a control device that operates in cooperation with each other.

Further, the hot water storage unit 200 includes a hot water storage tank 20. The other end of the water inlet pipe L1 is connected to the lower part of the hot water storage tank 20, and the other end of the hot water outlet pipe L2 is connected to the upper part of the hot water storage tank 20. The hot water storage tank 20 is provided with three temperature sensors T1 to T3 at intervals from the lower side to the upper side.

The water heat exchanger 2, the hot water storage tank 20, and the circulation pump P constitute the water circuit according to the present disclosure.

Further, a water supply pipe L11 provided with a pressure reducing valve 21 is connected to the lower part of the hot water storage tank 20. One end of the pipe L12 is connected to the upper part of the hot water storage tank 20, and the other end of the pipe L12 is connected to the first water inlet port of the hot water supply mixing valve 22. A pipe L13 branched from the water supply pipe L11 is connected to the second water inlet port of the hot water supply mixing valve 22.

One end of the hot water supply pipe L14 is connected to the water outlet of the hot water supply mixing valve 22, and a hot water supply unit 30 (for example, a faucet, a bath curan, a shower) is connected to the other end of the hot water supply pipe L14. A hot water supply temperature sensor 23 is provided in the hot water supply pipe L14.

FIG. 2 is a control block diagram of the hot water supply device of the first embodiment. The control device 10 includes a microcomputer, an input / output circuit, and the like, and as shown in FIG. 2, the discharge pipe temperature sensor 11, the outdoor temperature sensor 12, the temperature sensors T1 to T3, the water inlet temperature sensor 13, the hot water temperature sensor 14, Based on the signals from the pressure sensor 15, the hot water supply temperature sensor 23, the rotation speed sensor and the flow rate sensor (not shown) provided in the circulation pump P, the compressor 1, the outdoor fan motor 6a, the electric expansion valve EV, It controls the circulation pump P, the hot water supply mixing valve 22, and the like.

The heat pump type hot water unit of the present embodiment includes a boiling operation in which the hot water in the hot water storage tank 20 is boiled by the heat pump unit 100, an antifreezing operation for preventing the water in the water heat exchanger 2 from freezing, and outdoor heat. A defrosting operation for melting the frost adhering to the exchanger 3 can be performed. Hereinafter, the boiling operation and the antifreeze operation will be described. Further, the defrosting operation according to the present embodiment is a so-called normal cycle defrosting operation, and detailed description thereof will be omitted.

(Boiling operation)
In the "boiling operation" in which the hot water in the hot water storage tank 20 is boiled by the heat pump unit 100 in the hot water supply device having the above configuration, the circulation pump P is operated to supply the hot water in the hot water storage tank 20 to the water inlet pipe L1 and the heat pump unit 100. It is circulated through the water heat exchanger 2 and the hot water pipe L2.

At this time, in the heat pump unit 100, the compressor 1 is operated with the electric expansion valve EV opened to a predetermined opening degree. The water supplied to the water heat exchanger 2 by the circulation pump P is warmed by heat exchange with the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 in the water heat exchanger 2.

(Freezing prevention operation)
The control device 10 according to the present disclosure has a first antifreezing operation for preventing freezing of the water heat exchanger 2 in a state where water is circulated in the water circuit, and a first antifreezing operation in which the amount of water circulating in the water circuit is the first antifreezing operation. It is configured so that the compressor 1 can be operated in a state less than that of the water heat exchanger 2 to perform a second antifreezing operation for preventing the water heat exchanger 2 from freezing.

In the first antifreeze operation, the control device 10 operates the circulation pump P to circulate the water in the hot water storage tank 20 through the water inlet pipe L1, the water heat exchanger 2 of the heat pump unit 100, and the hot water outlet pipe L2. ..

In the first antifreeze operation, the water heat exchanger 2 is heated by the heat of the water supplied to the water heat exchanger 2 of the heat pump unit 100 by the circulation pump P, and the freezing of the water heat exchanger 2 is suppressed. ..

In the second antifreeze operation, the control device 10 operates the heat pump unit 100 in a state where the amount of water circulating in the water circuit is smaller than that in the first antifreeze operation to heat the water heat exchanger 2. Specifically, in the second antifreeze operation, the control device 10 operates the compressor 1, and the water heat exchanger 2 is heated by the high-temperature and high-pressure gas refrigerant discharged from the compressor 1.

In the boiling operation of the present embodiment, the compressor 1 is controlled so that the operating frequency is fixed at about 60 Hz. In the present embodiment, the operating frequency of the compressor 1 in the second antifreeze operation is lower than the operating frequency of the compressor 1 in the boiling operation. For example, in the present embodiment, in the second antifreeze operation, the compressor 1 is controlled so that the operating frequency is about 32 Hz. Further, in the defrosting operation, the compressor 1 is controlled so that the operating frequency is about 80 Hz.

In the boiling operation of the present embodiment, the electric expansion valve EV is controlled so that the drive pulse is between the opening degree corresponding to 60 pls and the opening degree corresponding to 470 pls. On the other hand, in the second antifreeze operation of the present embodiment, the electric expansion valve EV is controlled so that the drive pulse has an opening degree corresponding to 470 pls (that is, fully open). Further, in the defrosting operation, the electric expansion valve EV is controlled so that the drive pulse has an opening degree (fully open) corresponding to 470 pls.

In the boiling operation of the present embodiment, the outdoor fan 6 is controlled so that the rotation speed is between 500 rpm and 800 rpm. In the second antifreeze operation, the outdoor fan 6 is controlled so that the rotation speed is 500 rpm. In the defrosting operation, the outdoor fan 6 is controlled so as not to be driven.

(Control of antifreeze operation by control device)
FIG. 3 is a control flowchart of the antifreeze operation executed by the control device 10 according to the present embodiment. Hereinafter, control of the antifreeze operation by the control device 10 of the present embodiment will be described with reference to FIG.

In the present embodiment, when the predetermined condition is satisfied, the control device 10 starts the antifreeze operation (step S1). Specifically, when the outdoor temperature detected by the outdoor temperature sensor 12 has passed a predetermined time (for example, 20 minutes) in a state where the outdoor temperature is lower than a predetermined temperature (for example, −10 ° C.). In addition, the anti-freezing operation is started. Alternatively, in the control device 10, at least one of the incoming water temperature detected by the incoming water temperature sensor 13 and the hot water outlet temperature detected by the hot water outlet temperature sensor 14 becomes lower than a predetermined temperature (for example, 3 ° C.). At that time, the antifreeze operation is started.

When the antifreeze operation is started, the control device 10 determines whether or not the first antifreeze operation can be executed while the circulation pump P is stopped (step S2). The control device 10 determines that the first antifreeze operation cannot be executed when it is expected that a sufficient amount of water circulation in the water circuit cannot be secured, and in other cases, the first antifreeze operation is performed. Is determined to be feasible.

In step S2, when it is found that the control device 10 cannot secure a sufficient amount of water circulation due to, for example, a failure of the circulation pump P, generation of air biting in the circulation pump P, freezing of the water pipe, or the like. Then, it is determined that the first antifreeze operation cannot be executed, and the process proceeds to step S8. Step S8 will be described later.

The time when it is found that a sufficient amount of water circulation cannot be secured due to the failure of the circulation pump P is, for example, the case where the hot water supply device of the present embodiment is abnormally stopped due to the failure of the circulation pump P.

In the hot water supply device of the present embodiment, for example, the detection value of the rotation speed of the circulation pump P detected by the rotation speed sensor (not shown) is 1 / of the indicated value regarding the rotation speed from the control device 10 to the circulation pump P. When it is 2 or less, the circulation pump P is considered to be out of order and stops abnormally. Specifically, for example, when the indicated value regarding the rotation speed from the control device 10 to the circulation pump P is 5000 rpm, and the detection value of the rotation speed detected by the rotation speed sensor of the circulation pump P is 2000 rpm. , The control device 10 abnormally stops the hot water supply device on the assumption that the circulation pump P is out of order.

When it is found that a sufficient amount of water circulation cannot be secured due to the occurrence of air biting in the circulation pump P, for example, when the hot water supply device is abnormally stopped due to the occurrence of air biting in the circulation pump P. be.

In the hot water supply device of the present embodiment, for example, when the rotation speed of the circulation pump P is a predetermined value (for example, 1000 rpm) or more, the flow rate detected by the flow rate sensor (not shown) is a predetermined value (for example, 0. When it is 2 l / min) or less, it is assumed that air biting has occurred in the circulation pump P, and the circulation pump P stops abnormally.

In the hot water supply device of the present embodiment, for example, when the rotation speed of the circulation pump P is a predetermined value (for example, 1000 rpm) or more, the pressure sensor 15 after a predetermined time (for example, 1 minute) has elapsed after the start of the compressor 1. When the pressure detected by is higher than a predetermined pressure (for example, 4.2 MPa), the circulation pump P is abnormally stopped as if air biting has occurred. When the compressor 1 is started when the water circulation amount cannot be sufficiently secured, the heat exchange between the refrigerant and the water in the water heat exchanger 2 becomes insufficient, and the pressure in the refrigerant circuit rises.

On the other hand, when the control device 10 determines that the first antifreeze operation can be executed, the control device 10 starts the first antifreeze operation (step S3).

Next, after the first antifreeze operation is started in step S3, the control device 10 determines whether or not the normal termination condition in which the first antifreeze operation is normally terminated is satisfied (step S4).

The control device 10 was detected by the incoming water temperature sensor 13 and the hot water temperature sensor 14 before a predetermined time (for example, 20 minutes) elapses after the first antifreeze operation is started. When the hot water temperature becomes equal to or higher than a predetermined temperature (for example, 6 ° C.), it is determined that the normal termination condition is satisfied, and the first antifreeze operation is terminated (step S4-1). After that, the control device 10 ends the antifreeze operation (step S12).

On the other hand, when the water entry temperature and the hot water outlet temperature when a predetermined time (for example, 20 minutes) has elapsed since the first antifreeze operation is started are less than the predetermined first temperature (for example, 6 ° C.), control is performed. The device 10 determines that the normal termination condition is not satisfied, and starts the operation of the compressor 1 (step S5). At this time, the operating frequency of the compressor 1, the opening degree of the electric expansion valve EV, and the rotation speed of the outdoor fan 6 may be the same as those in the boiling operation.

Next, after the compressor 1 is started, the control device 10 determines whether or not a water circulation failure has occurred in the water circuit (step S6).

When a circulation failure occurs in the water circuit via the water heat exchanger 2, when the compressor 1 is started, the heat exchange between the refrigerant and water in the water heat exchanger 2 becomes insufficient, and the refrigerant circuit The pressure inside rises. In the control device 10, when the pressure detected by the pressure sensor 15 after a lapse of a predetermined time (for example, 2 minutes) after the start of the compressor 1 is higher than the predetermined pressure, poor water circulation in the water circuit occurs. If so, the first antifreeze operation is terminated (step S7).

On the other hand, if it is determined in step S6 that poor water circulation has not occurred, the control device 10 abnormally stops the first antifreeze operation (step S6-1) and ends the antifreeze operation. (Step S12).

After terminating the first antifreeze operation in step S7, the control device 10 determines whether or not the second antifreeze operation is possible (step S8). The control device 10 determines that the second antifreeze operation is possible when all of the following five conditions (1-1) to (1-5) are satisfied, and starts the second antifreeze operation. (Step S9). In the second antifreeze operation, the control device 10 controls the compressor 1 so that the operating frequency of the compressor 1 becomes about 32 Hz, and electrically expands so that the opening degree of the electric expansion valve EV becomes 470 pls (fully open). The valve EV is controlled, and the outdoor fan 6 is controlled so that the rotation speed of the outdoor fan 6 becomes 500 rpm.

(1-1) The outdoor temperature detected by the outdoor temperature sensor 12 is less than a predetermined temperature (for example, 4 ° C.).

(1-2) At least one of the incoming water temperature detected by the incoming water temperature sensor 13 and the hot water outlet temperature detected by the hot water outlet temperature sensor 14 is lower than a predetermined temperature (for example, 3 ° C.).

(1-3) The discharge pipe temperature detected by the discharge pipe temperature sensor 11 is less than a predetermined temperature (for example, 15 ° C.).

(1-4) Poor circulation of water through the water heat exchanger 2 in the water circuit has occurred. As described above, the presence or absence of poor circulation of water through the water heat exchanger 2 in the water circuit is based on the pressure of the refrigerant in the refrigerant circuit when the compressor 1 is operated in the first antifreeze operation.

(1-5) No abnormality has occurred in the refrigerant circuit. It is assumed that the control device 10 has an abnormality in the refrigerant circuit, for example, when an abnormality has occurred in the compressor 1 or when an abnormality has occurred in the outdoor fan 6.

In addition, when the second antifreeze operation is once executed, the condition that the second antifreeze operation is possible is that a predetermined time has elapsed from the end of the previous second antifreeze operation. You may add it. The predetermined time may be changed according to the outside air temperature. For example, when the outside air temperature is low, it is preferable to shorten the predetermined time.

In step S9, after the second antifreeze operation is started, the control device 10 determines whether or not the normal termination condition in which the second antifreeze operation is normally terminated is satisfied (step S10). After starting the second antifreeze operation, the control device 10 is said to satisfy the normal termination condition when any one of the following three conditions (2-1) to (2-3) is satisfied. After determining, the second antifreeze operation is terminated (step S11). After that, the control device 10 ends the antifreeze operation (step S12).

(2-1) A predetermined time (for example, 2 minutes) or more has passed since the second antifreeze operation was started, and the condensation temperature in the water heat exchanger 2 is set to a predetermined second temperature (for example, 40 ° C.). Over. In the present embodiment, the condensation temperature in the water heat exchanger 2 is estimated from the pressure of the refrigerant circuit detected by the pressure sensor 15.

(2-2) A predetermined time (for example, 30 minutes) or more has passed since the second antifreeze operation was started. The predetermined time may be changed according to the outside air temperature.

(2-3) The outdoor temperature detected by the outdoor temperature sensor 12 is a predetermined temperature (for example, 4 ° C.) or higher.

On the other hand, when the control device 10 determines that an abnormality has occurred in the refrigerant circuit, it determines that the normal termination condition is not satisfied, and abnormally stops the second antifreeze operation (step S10-1). The antifreeze operation is terminated (step S12). The control device 10 determines that an abnormality has occurred in the refrigerant circuit, for example, when an abnormality has occurred in the compressor 1 or when an abnormality has occurred in the outdoor fan 6.

According to the above embodiment, the control device 10 is configured to be able to execute the second antifreezing operation in which the compressor 1 is operated to warm the water heat exchanger 2 in a state where the circulation pump P is not operating. Even if the pump P cannot be operated due to a failure or the like, freezing of the water heat exchanger 2 can be suppressed by executing the second antifreezing operation.

According to the above embodiment, when the water circulation failure through the water heat exchanger 2 occurs in the water circuit, the second antifreeze operation is executed, so that the circulation pump P cannot be operated due to a failure or the like. The second antifreeze operation can be appropriately executed in the state.

When a circulation failure occurs in the water circuit via the water heat exchanger 2, when the compressor 1 is started in the first antifreeze operation, the heat exchange between the refrigerant and water in the water heat exchanger 2 is not possible. It becomes sufficient and the pressure in the refrigerant circuit rises. According to the present disclosure, the control device 10 executes the second antifreeze operation when the pressure of the refrigerant in the refrigerant circuit after starting the compressor 1 in the first antifreeze operation is higher than a predetermined pressure. , The second anti-freezing operation can be appropriately executed when the circulation pump P cannot be operated due to a failure or the like.

According to the above embodiment, since the operating frequency of the compressor 1 in the second antifreeze operation is lower than the operating frequency of the compressor 1 in the boiling operation, the pressure of the refrigerant is excessively increased in the second antifreeze operation. Can be suppressed.

According to the above embodiment, in the second antifreeze operation, the outdoor fan 6 that supplies air to the outdoor heat exchanger 3 is driven, so that the heat exchange between the refrigerant and the air in the outdoor heat exchanger 3 is promoted. NS. As a result, the increase in the low pressure in the refrigerant circuit is suppressed, so that the excessive increase in the pressure of the refrigerant can be suppressed.

According to the above embodiment, the second antifreeze operation ends when the condensation temperature in the water heat exchanger 2 becomes higher than the second temperature. Therefore, for example, the second temperature is set to the boiling temperature (40 in the present embodiment). By setting the temperature lower than (° C.), it is possible to suppress an excessive increase in the pressure of the refrigerant in the second antifreeze operation.

According to the above embodiment, after the second antifreeze operation is once executed, the discharge pipe temperature raised by the second antifreeze operation becomes lower than the predetermined third temperature, and then the next second antifreeze operation is performed. Become executable. As a result, for example, by setting the third temperature to a temperature at which the compressor 1 is sufficiently cooled (15 ° C. in the present embodiment), the second antifreeze operation is once executed and then the second freezing is performed. Since the time until the preventive operation is executed is secured, it is possible to prevent the second antifreeze operation from being frequently executed.

Although the embodiments have been described above, it will be understood that various modifications of the embodiments and details are possible without departing from the purpose and scope of the claims.

For example, in the above embodiment, the heat pump type hot water unit according to the present disclosure has been applied to a hot water supply device, but the present invention is not limited to this, and may be applied to other devices such as a floor heating device.

For example, the condensation temperature in the water heat exchanger 2 was used under the condition (2-1), which is one of the termination conditions of the second antifreeze operation, but the temperature of the water heat exchanger 2 is not limited to this. Alternatively, the ambient temperature of the water heat exchanger 2 may be measured and used.

1 ... Compressor 2 ... Water heat exchanger 3 ... Outdoor heat exchanger 4 ... Accumulator 6 ... Outdoor fan 6a ... Outdoor fan motor 10 ... Control device (control unit)
11 ... Discharge pipe temperature sensor 12 ... Outdoor temperature sensor 13 ... Water inlet temperature sensor 14 ... Hot water temperature sensor 15 ... Pressure sensor 20 ... Hot water storage tank 21 ... Pressure reducing valve 22 ... Hot water supply mixing valve 23 ... Hot water supply temperature sensor 30 ... Hot water supply unit 100 ... Heat pump Unit (heating part)
200 ... Hot water storage unit EV ... Electric expansion valve (expansion mechanism)
P ... Circulation pump T1 to T3 ... Temperature sensor

Claims (9)

A refrigerant circuit having a compressor (1), a water heat exchanger (2), an expansion mechanism (EV), and an air heat exchanger (3),
A water circuit having a circulation pump (P) that circulates water via the water heat exchanger (2), and
A control unit (10) for controlling the refrigerant circuit and the circulation pump (P) is provided.
The first anti-freezing operation that prevents the water heat exchanger (2) from freezing while the water is circulated in the water circuit, and the amount of water that circulates in the water circuit is smaller than that of the first anti-freezing operation. A heat pump type hot water unit characterized in that the compressor (1) is operated in a state to execute a second antifreezing operation for preventing the water heat exchanger (2) from freezing. The claim is characterized in that the control unit (10) executes the second anti-freezing operation when a poor circulation of water via the water heat exchanger (2) occurs in the water circuit. Item 1. The heat pump type hot water unit according to item 1. The control unit (10) started the compressor (1) when the inlet temperature or the outlet temperature of the water heat exchanger (2) was lower than the predetermined first temperature in the first antifreeze operation. In this case, the second antifreeze operation is executed when the pressure of the refrigerant circulating in the refrigerant circuit after the start of the compressor (1) is higher than a predetermined pressure. The heat pump type hot water unit according to 1 or 2. The operating frequency of the compressor (1) in the second antifreeze operation is lower than the operating frequency of the compressor (1) in the boiling operation of boiling water in the water circuit. The heat pump type hot water unit according to any one of Items 1 to 3. A fan (6) for supplying air to the air heat exchanger (3) is provided.
The control unit (10) controls the fan (6) so that the fan (6) is driven in the second antifreeze operation, according to any one of claims 1 to 4. The heat pump type hot water unit described. The control unit (10) controls the refrigerant circuit so that the second antifreeze operation is terminated when the condensation temperature in the water heat exchanger (2) is higher than the predetermined second temperature. The heat pump type hot water unit according to any one of claims 1 to 5, which is characterized. The control unit (10) is characterized in that the refrigerant circuit is controlled so as to start the second antifreeze operation when the discharge pipe temperature of the compressor (1) is lower than a predetermined third temperature. The heat pump type hot water unit according to any one of claims 1 to 6. The expansion mechanism (EV) is an electric valve and
The opening degree of the expansion mechanism (EV) in the second antifreeze operation is larger than the opening degree of the expansion mechanism (EV) in the boiling operation for boiling water in the water circuit. Item 2. The heat pump type hot water unit according to any one of Items 1 to 7. The invention according to any one of claims 1 to 8, wherein the second antifreeze operation can be executed again when a predetermined time has elapsed from the end of the second antifreeze operation. Heat pump type hot water unit.

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