JPH1172268A - Heat pump hot water supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable returning of a refrigerant to a compressor in the defrosting operation from a path built by connecting the inlet side of an evaporator to the inlet side of the compressor through a solenoid valve. SOLUTION: In this heat pump hot water supply apparatus, a compressor 1, a four-way valve 2, a condenser 3 for heating water of a hot water supply circuit, an expansion valve 4 and an evaporator 5 are connected sequentially in a ring while the inlet side of the evaporator 5 is connected to the inlet side of the compressor 1 through a solenoid valve 10 and with the solenoid valve 10 closed, a refrigerant is circulated to perform a hot water supply operation. The outlet side of the compressor 1 is connected by the four-way valve 2 to the outlet side of the evaporator 5 while the solenoid valve 10 is opened and the refrigerant is circulated through the compressor 1, the evaporator 5 and the solenoid valve 10 sequentially to perform a defrosting operation of the evaporator 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat pump water heater, and more particularly to a heat pump water heater for performing a defrosting operation of an evaporator.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional heat pump water heater. In FIG. 2, 21 is a compressor, 22 is a four-way valve, 23
Is a condenser, 24 is an expansion valve, and 25 is an evaporator. Compressor 21, four-way valve 22, condenser 23, expansion valve 24, evaporator 2
5 are sequentially connected in a ring to form a heat pump circuit. In FIG. 2, reference numeral 26 denotes a check valve for establishing a reverse cycle, and reference numeral 27 denotes a strainer for preventing dust and other foreign substances from flowing into the expansion valve 24.

[0003] A circulating pump 28 for sending city water to the condenser 23 for heating and discharging hot water, a water control valve 29 for keeping the temperature of the hot water constant, and a condenser 23 constitute a hot water supply circuit. .

In this conventional heat pump water heater, the refrigerant in the heat pump circuit is compressed by a compressor 21 and the water in the water heater circuit is heated by a condenser 23 to condense the refrigerant in the heat pump circuit. It is evaporated by atmospheric heat and returned to the compressor 21. In this case, in the hot water supply circuit, city water is supplied to the condenser 23 by the circulation pump 28, and is heated by the condenser 23 to discharge hot water.

In such a heat pump hot water supply apparatus, when frost adheres to the evaporator 25 in winter or the like, the hot water supply capacity is reduced, and thus the defrosting operation of the evaporator 25 is periodically performed. Such a defrosting operation is performed by reversing a normal operation cycle. That is, the outlet side of the compressor 21 and the evaporator 2
By switching the setting of the four-way valve 22 (to the solid line side) so that the outlet side of No. 5 is connected, high-temperature refrigerant gas is supplied from the compressor 21 to the evaporator 25 to defrost and condense the cooled and condensed refrigerant. The heat was exchanged with the hot water in the hot water supply circuit in the hot water supply circuit 23 to evaporate and return the hot water to the compressor 21.

[0006]

However, in this conventional heat pump hot water supply apparatus, when performing a defrosting operation, heat of hot water in a hot water supply circuit is taken to evaporate a refrigerant in a heat pump cycle. During operation, there is a problem that the temperature of hot water in the hot water supply circuit decreases.

In this conventional heat pump circuit,
Each time the defrosting operation is performed, the condenser 23 is cooled, the water in the condenser 23 freezes, and the condenser 23 is damaged.
Although water must be circulated in the hot water supply circuit during the defrosting operation, the discharge pressure in the hot water supply circuit does not increase during the defrosting operation, so that the water control valve 29 remains closed. That is, the water control valve 29 is controlled by the discharge pressure of the compressor 21. The valve opens when the pressure is about 24 kg / cm ² or more, and closes when the pressure is less than about 24 kg / cm ² . When the cycle is reversed in the defrosting operation,
There is a possibility that the discharge pressure drops, the water control valve 29 closes, the water cannot be circulated, and the water freezes. For this purpose, conventionally, an electromagnetic valve 30 is provided in parallel with the water control valve 29, and this electromagnetic valve 30 is provided.
Was opened to circulate water.
There is a problem in that a separate means for opening and closing is required, which complicates the configuration.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the conventional apparatus. The temperature of the hot water supply circuit drops during the defrosting operation, and the configuration and control of the hot water supply circuit for the defrosting operation. It is an object of the present invention to provide a heat pump hot water supply apparatus that solves the problem of the conventional apparatus in that the heat pump becomes complicated.

[0009]

To achieve the above object, a heat pump hot water supply apparatus according to claim 1 includes a compressor, a four-way valve, a condenser for heating water in a hot water supply circuit, an expansion valve,
And a heat pump water heater in which an evaporator and an evaporator are sequentially connected in a ring shape, the inlet side of the evaporator and the inlet side of the compressor are connected via an electromagnetic valve.

In the heat pump hot water supply apparatus according to the second aspect, the compressor, the four-way valve, the condenser for heating water in the hot water supply circuit, the expansion valve, and the evaporator are sequentially connected in a ring shape.
In a heat pump water heater that connects an inlet side of the evaporator and an inlet side of the compressor via an electromagnetic valve and circulates refrigerant in a state where the electromagnetic valve is closed to perform a hot water supply operation, the four-way valve is used for the heat pump water heater. Connect the outlet side of the compressor and the outlet side of the evaporator, open the solenoid valve, circulate the refrigerant in the order of the compressor, the evaporator, and the solenoid valve to perform the defrosting operation of the evaporator. I did it.

In the above heat pump hot water supply apparatus, it is desirable to provide a check valve on the outlet side of the condenser.

In the above heat pump hot water supply apparatus, it is desirable that a capillary tube is interposed between the solenoid valve and the compressor.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a view showing one embodiment of a heat pump hot water supply apparatus according to the present invention, wherein 1 is a compressor, 2 is a four-way valve, 3 is a condenser, 4 is an expansion valve, 5 is an evaporator, and 6 is a circulation pump. , 7 are water control valves.

The compressor 1 is provided for compressing the refrigerant and circulating it in the heat pump circuit. The four-way valve 2 is provided for switching the connection state of the compressor 1 in the heat pump circuit to change the flow path of the refrigerant. The condenser 3 is provided for heating city water with latent heat formed in the refrigerant. The expansion valve 4 is provided to reduce the pressure of the refrigerant and vaporize the refrigerant. Evaporator 5
Is provided to convert latent heat into the refrigerant.

A heat pump circuit is formed by sequentially connecting the compressor 1, the four-way valve 2, the condenser 3, the expansion valve 4, and the evaporator 5 in a ring shape. City water is supplied to the condenser 3 via the circulation pump 6 and the water control valve 7, and the condenser 3, the circulation pump 6 and the water control valve 7 constitute a hot water supply circuit. Further, the inlet side of the evaporator 5 and the inlet side of the compressor 1 in the heat pump circuit are connected via a solenoid valve 10 and a capillary tube 11. Note that the capillary tube 11 is provided to prevent a large amount of liquid refrigerant from flowing into the compressor 1 during the defrosting operation.

Next, the operation of the heat pump water heater configured as described above will be described. First, the four-way valve 2 is set (on the dotted line side) so that the outlet side of the compressor 1 and the inlet side of the condenser 3 are connected. In this case, the inlet (suction) side of the compressor 1 is connected to the evaporator 5. The refrigerant in the heat pump circuit is supplied to the compressor 1, the four-way valve 2, the condenser 3, the expansion valve 4,
The water in the hot water supply circuit is heated and circulated in the order of the evaporator 5 to supply hot water.

When performing the defrosting operation, the four-way valve 2 is set (on the solid line side) so that the outlet side of the compressor 1 is connected to the outlet side of the evaporator 5. In this case, the inlet side of the condenser 3 is connected to the inlet side of the compressor 1. In this state, the high-temperature discharge gas is sent from the compressor 1 to the evaporator 5, and the liquid refrigerant condensed by removing the frost from the evaporator 5 is opened to the electromagnetic valve 10, guided to the capillary tube 11, and passed through the capillary tube 11. The low-pressure refrigerant is returned to the compressor 1. That is, in the compressor 1, the refrigerant gas has a high temperature and a high pressure on the outlet side in order to compress the refrigerant gas. In this state, when the four-way valve 2 is connected to the outlet side of the low-pressure evaporator 5, the discharge gas instantaneously flows into the evaporator 5, but the pressure drops rapidly.

At this time, a check valve 8 is provided on the inlet side of the expansion valve 4, so that the refrigerant liquid flowing out of the evaporator 5 does not flow into the condenser 3. That is, although the expansion valve 4 is normally closed and the refrigerant liquid does not flow into the condenser 3, when a large amount of frost adheres to the evaporator 5, the temperature of the evaporator 5 is lower than the temperature rise of the thermosensitive cylinder of the expansion valve 4. Since the pressure rise is low, a state in which the expansion valve 4 remains open may occur. Therefore, a check valve 8 is provided on the inlet side of the expansion valve 4 to prevent the low-temperature refrigerant from flowing into the condenser 3 and freezing and breaking the condenser 3.

In this heat pump circuit, since low-temperature refrigerant does not flow into the condenser 3 during the defrosting operation, it is necessary to supply city water to prevent freezing in the condenser 3 during the defrosting operation. Absent. Therefore, it is not necessary to drive the circulation pump 6 during the defrosting operation, and it is not necessary to provide an electromagnetic valve in the hot water supply circuit as in the conventional device. Therefore, the configuration and control of the hot water supply circuit portion are simplified.

[0020]

As described above, according to the heat pump water heater according to the first aspect, the inlet side of the evaporator and the inlet side of the compressor are connected via the electromagnetic valve, so that the defrosting operation can be performed. In this way, the refrigerant can be returned to the compressor from this path, and since the low-temperature refrigerant does not flow into the condenser during the defrosting operation, the hot water temperature of the hot water supply circuit does not decrease, and the configuration of the hot water supply circuit and Control becomes easy.

Further, in the heat pump water heater according to claim 2, the outlet side of the compressor and the outlet side of the evaporator are connected by a four-way valve, and the solenoid valve is opened to transfer the refrigerant to the compressor, Because the evaporator and the solenoid valve were circulated in order to perform the defrosting operation of the evaporator,
During the defrosting operation, the low-temperature refrigerant does not flow into the condenser, the temperature of the hot water in the hot water supply circuit does not decrease, and the configuration and control of the hot water supply circuit become easy.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a heat pump hot water supply apparatus according to the present invention.

FIG. 2 is a view showing a conventional heat pump hot water supply apparatus.

[Explanation of symbols]

1 ‥‥‥ compressor, 2 ‥‥‥ four-way valve, 3 ‥‥‥ condenser, 4
‥‥‥ Expansion valve, 5 ‥‥‥ Evaporator, 6 ‥‥‥ Circulation pump,
7 mm water control valve, 10 mm solenoid valve, 11 mm capillary tube

Claims (4)

[Claims] 1. A heat pump water heater in which a compressor, a four-way valve, a condenser for heating water in a hot water supply circuit, an expansion valve, and an evaporator are sequentially connected in a ring shape, wherein an inlet side of the evaporator and the compressor are connected. A heat pump hot water supply device, wherein the heat pump hot water supply device is connected to an inlet side of the heat pump via an electromagnetic valve. 2. A compressor, a four-way valve, a condenser for heating water in a hot water supply circuit, an expansion valve, and an evaporator are sequentially connected in a ring shape, and an inlet side of the evaporator and an inlet side of the compressor are connected. In a heat pump water heater that connects via an electromagnetic valve and circulates refrigerant in a state where the electromagnetic valve is closed to perform a hot water supply operation, the outlet side of the compressor and the outlet side of the evaporator are connected by the four-way valve. A heat pump hot water supply apparatus, wherein the electromagnetic valve is opened, and the refrigerant is circulated in the order of the compressor, the evaporator, and the electromagnetic valve to perform a defrosting operation of the evaporator. 3. The heat pump water heater according to claim 1, wherein a check valve is provided on an outlet side of the condenser. 4. The heat pump hot water supply apparatus according to claim 1, wherein a capillary tube is interposed between the solenoid valve and the compressor.