JPH09318229A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the deterioration of cooling capacity due to a drain pan heater, and prevent the increasing of amount of refrigerant by a method wherein a bypass circuit, conducting the flow of refrigerant only upon defrosting operation, is formed in parallel to a choking mechanism while the drain pan heater is interposed in the bypass circuit. SOLUTION: A drain pan heater 20 is interposed in a bypass circuit 12, formed in parallel to a throttling mechanism 8. Upon cooling operation, refrigerant is circulated in the sequence of a compressor 1, a three-way valve 2, a heat source side heat exchanger 3, a receiver 4, a check valve 5, a solenoid opening and closing valve 7, the throttling mechanism 8, a utilizing side heat exchanger 9 and an accumulator 10. Upon defrosting operation, the refrigerant is circulated in the sequence of the compressor 1, the three-way valve 2, a hot-gas circuit 11, the bypass circuit 12, a solenoid opening and closing valve 13, the drain pan heater 20, the utilizing side heat exchanger 9 and the accumulator 10 while frost is molten under a process that the refrigerant passes through the utilizing side heat exchanger 9 to drop frost into a drain pan and heat is released under a process that the refrigerant passes through the drain pan heater 20 to melt the frost in the drain pan.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner,
The present invention relates to a refrigerator such as a refrigerator and a refrigerated showcase.

[0002]

2. Description of the Related Art A refrigerant circuit of this type of refrigerating apparatus is shown in FIG. During the cooling operation of the refrigeration system, the gas refrigerant discharged from the compressor 1 enters the heat source side heat exchanger 3 via the three-way valve 2 as shown by the solid arrow, and radiates heat to the outside to be condensed and liquefied. .

This liquid refrigerant passes through the receiver 4, the check valve 5, the drain pan heater 6, and the electromagnetic opening / closing valve 7 and then enters the throttling mechanism 8 composed of an expansion valve and the like, where it is adiabatically expanded by being throttled.

This refrigerant enters the heat exchanger 9 on the use side, where it evaporates and vaporizes by cooling the air in the refrigerator, and then returns to the compressor 1 via the accumulator 10.

When a large amount of frost adheres to the surface of the heat exchanger 9 on the use side, the defrost operation is performed. The refrigerant discharged from the compressor 1 during the defrost operation enters the drain pan heater 6 via the three-way valve 2 and the hot gas circuit 11 as shown by the dashed arrow, and after radiating heat there, the bypass circuit 12
After entering the heat exchanger 9 on the use side through the electromagnetic on-off valve 13 provided in the above, the frost adhering to the surface thereof is melted to lower the temperature, and then returns to the compressor 1 via the accumulator 10. During the defrost operation, the three-way valve 2 is switched as shown and the electromagnetic opening / closing valve 7 is closed.

FIG. 5 shows a schematic structure of the indoor unit. An air inlet is provided inside the housing 23 of the indoor unit.
A utilization side heat exchanger 9 is erected so as to face 26, and a fan 24 is arranged so as to face the air outlet 27. A drain pan 21 is installed under the heat exchanger 9 on the use side, and the drain pan heater 6 is installed along the drain pan 21.
Is provided.

When the fan 24 is driven by the motor 25,
The inside air is sucked into the housing 23 from the air suction port 26, is cooled in the process of passing through the use side heat exchanger 9, and
It is urged by 24 and is blown out from the air outlet 27 into the refrigerator.

Drain that has condensed on the surface of the use side heat exchanger 9 drops into the drain pan 21 and is discharged through a drain hose (not shown). Further, during the defrost operation, the frost that has fallen from the use-side heat exchanger 9 enters the drain pan 21 and is melted by being heated by the drain pan heater 6.

[0009]

In the above conventional refrigeration system, the liquid refrigerant flows through the drain pan heater 6 and radiates heat during the cooling operation, so that the cooling capacity is reduced and the refrigerant circuit is cooled. There has been a problem that the amount of refrigerant to be filled increases accordingly.

[0010]

The present invention has been invented to solve the above-mentioned problems, and the gist of the invention is to provide a compressor, a heat source side heat exchanger, a throttle mechanism, and a use side heat exchange. In the refrigerating device, which forms a refrigeration cycle with a cooling device and a drain pan is installed in the lower part of the utilization side heat exchanger, and a drain pan heater is provided along the drain pan, the refrigerant is supplied in parallel with the throttle mechanism only during defrost operation. A refrigerating apparatus is characterized in that a bypass circuit for flowing is formed, and the drain pan heater is interposed in the bypass circuit.

However, the refrigerant flows through the drain pan heater interposed in the bypass circuit only during the defrost operation.

Another feature is that a pump down solenoid valve is provided between the heat source side heat exchanger and the throttle mechanism and in parallel with the bypass circuit, and the bypass circuit is opened only during defrost operation. There is an electromagnetic on-off valve.

However, during the defrost operation, the pump-down solenoid valve is closed and the solenoid on-off valve is opened, so that the refrigerant flows through the bypass circuit and the drain pan heater and the solenoid on-off valve interposed therein. During the pump down operation, the pump down solenoid valve is opened and the solenoid on-off valve is closed, so that the refrigerant flows through the pump down solenoid valve and the throttle mechanism, but does not flow through the drain pan heater.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. As shown in FIG. 1, a drain pan heater 20 is provided in a bypass circuit 12 formed in parallel with the diaphragm mechanism 8. The drain pan heater 6, which has been conventionally provided on the upstream side of the bypass circuit 12, is eliminated. The other configuration is the same as that of the conventional one shown in FIGS. 4 and 5, and the corresponding members are denoted by the same reference numerals and description thereof is omitted.

During the cooling operation of the refrigeration system, however, the refrigerant is compressed by the compressor 1, the three-way valve 2, the heat source side heat exchanger 3, the receiver 4, the check valve 5, the electromagnetic on-off valve 7, as shown by the solid arrow. The throttling mechanism 8, the utilization side heat exchanger 9, and the accumulator 10 are circulated in this order.

Since there is no drain pan heater in this circulation path, the cooling capacity can be improved by not radiating heat here, and the amount of the refrigerant filled in the drain pan heater can be reduced by the amount of the liquid refrigerant.

During the defrost operation of the refrigeration system, the refrigerant is compressed by the compressor 1, the three-way valve 2, the hot gas circuit 11, the bypass circuit 12, the electromagnetic on-off valve 13, the drain pan heater 20, the heat exchange on the use side, as indicated by the broken line arrow. The container 9 and the accumulator 10 are circulated in this order. Then, in the process of passing through the heat exchanger 9 on the use side, the frost adhering to the surface of the heat exchanger 9 is melted and the frost 21 is drained.
The frost dropped inside the drain pan 21 is melted by radiating heat in the process of flowing through the drain pan heater 20.

A second embodiment in which the present invention is applied to a reverse cycle defrost type refrigeration system is shown in FIG. The indoor unit is the same as the conventional unit shown in FIG. During the cooling operation of this refrigeration system, the refrigerant discharged from the compressor 1 enters the heat source side heat exchanger 3 via the four-way valve 15 as shown by the solid arrow, and radiates heat to the outside to be condensed and liquefied. . This liquid refrigerant enters the throttling mechanism 8 including an expansion valve through the check valve 19 and is adiabatically expanded by being throttled there.

This refrigerant enters the heat exchanger 9 on the use side, where it evaporates by cooling the air in the refrigerator, and then returns to the compressor 1 via the four-way valve 15 and the accumulator 10.

During the heating operation, the refrigerant is, as indicated by the broken line arrow, the compressor 1, the four-way valve 15, the use side heat exchanger 9, the throttle mechanism 8, and the capillary tube interposed in the bypass passage 17.
18, the heat source side heat exchanger 3, the four-way valve 15, and the accumulator 10 are circulated in this order.

During the defrost operation, the refrigerant enters the utilization side heat exchanger 9 through the compressor 1 and the four-way valve 15, where the frost adhering to the surface thereof is melted to lower the temperature. As shown by the white arrow, this refrigerant enters the bypass circuit 12 and radiates heat in the process of passing through the drain pan heater 20 interposed therein to melt the frost that has fallen into the drain pan 21. And
Check valve 14, capillary tube 18 inserted in bypass line 17, heat source side heat exchanger 3, four-way valve 15, accumulator 10
And returns to the compressor 1.

Since the drain pan heater 20 is interposed in the bypass circuit 12 through which the refrigerant flows only during the defrost operation, the refrigerant does not flow through the drain pan heater 20 during the cooling operation and the heating operation of the refrigeration system, and therefore, It is possible to prevent the capacity loss during the cooling operation and the heating operation, and reduce the amount of refrigerant charged.

As shown in FIG. 3, a pump down solenoid valve 28 is provided between the heat source side heat exchanger 3 and the throttling mechanism 8 and in parallel with the bypass circuit 12, and the bypass circuit 12 is subjected to defrost operation. It is possible to provide an electromagnetic on-off valve 29 that is opened only at the time. By doing so, during the pump down operation performed to recover the liquid refrigerant in the low pressure refrigerant pipe to the high pressure refrigerant pipe side prior to the stop of the compressor 1, the pump down solenoid valve 28 is opened and the solenoid opening / closing valve is opened. By closing 29, the liquid refrigerant can be prevented from passing through the drain pan heater 20.

[0024]

According to the present invention, since the refrigerant flows through the drain pan heater only during the defrosting operation, it is possible to prevent the capacity of the refrigerating device from being lowered and to reduce the amount of the refrigerant filled.

If a pump-down solenoid valve is provided between the heat source side heat exchanger and the throttle mechanism and in parallel with the bypass circuit and a solenoid valve that is opened only during defrost operation is provided in the bypass circuit, pump down It is possible to prevent the refrigerant from flowing through the drain pan heater during operation.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a refrigerant circuit diagram showing a modified example of the second embodiment.

FIG. 4 is a refrigerant circuit diagram of a conventional refrigeration system.

FIG. 5 is a schematic cross-sectional view of an indoor unit of a conventional refrigeration system.

[Explanation of symbols]

 1 compressor 3 heat source side heat exchanger 8 throttling mechanism 9 user side heat exchanger 20 drain pan heater 12 bypass circuit

Claims (2)

[Claims] 1. A refrigeration cycle is formed by a compressor, a heat source side heat exchanger, a throttle mechanism, and a use side heat exchanger, and a drain pan is installed below the use side heat exchanger, and a drain pan is provided along the drain pan. A refrigerating apparatus provided with a heater, wherein a bypass circuit for flowing a refrigerant only in a defrost operation is formed in parallel with the throttle mechanism, and the drain pan heater is interposed in the bypass circuit. 2. A pump down solenoid valve is provided between the heat source side heat exchanger and the throttle mechanism and in parallel with the bypass circuit, and an electromagnetic on-off valve that is opened only during defrost operation is provided in the bypass circuit. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is provided.