JPS5810936Y2 - Air conditioning equipment - Google Patents

Description

[Detailed description of the invention] The present invention is designed to suppress the compressor discharge pressure temperature, etc. within a predetermined value range, and to keep the compressor discharge pressure and temperature within a predetermined value range, even when severe load fluctuations occur due to outside air fluctuations during heating operation in the winter, in heating and cooling systems using refrigerant circuits. In addition to minimizing losses and making effective use of equipment, the condensate in the evaporator is smoothly returned to the low pressure side during frost operation, and heat exchange from the compressor to the high-temperature gas in the evaporator is effectively achieved. The purpose is to shorten the defrosting time.

In conventional heating and cooling systems using refrigerant circuits, overload heating operation during high outside temperatures in winter can cause the compressor to overload, causing thermal decomposition of the refrigerant and changes in the viscosity and deterioration of the lubricating oil in the compressor. There was a risk that the compressor body would burn out.

On the other hand, in a reverse cycle defrost operation in which frost adhering to the evaporator is removed in a reverse cycle, the condensed and liquefied refrigerant is stored in the evaporator during defrosting, and high-temperature gas from the compressor flows into the evaporator. Otherwise, the defrost will fail.

In addition, due to the above reasons, after the defrost operation is completed, the operation switches to the normal cycle, which causes liquid refrigerant to be sent to the compressor and performs wet operation, which prevents troubles such as oil spills and damage to valves and packings. It was the cause.

The present invention is based on and solves the above problems.

As a configuration for this purpose, the present invention sequentially connects a compressor, a four-way valve for switching between cooling and heating, an indoor heat exchanger, a throttling mechanism, an outdoor heat exchanger, the four-way valve for switching between cooling and heating, an accumulator, and the compressor in an annular manner. and the throttle mechanism has at least two stages of capillary tubes, a first capillary tube on the indoor side heat exchanger side and a second capillary tube on the outdoor side heat exchanger side, and the first capillary tube A second liquid receiver is arranged through a solenoid valve, and a gas venting pipe led out from the upper part of the liquid receiver is joined with a third capillary tube for liquid drainage led out from the lower part. The compressor is connected to the accumulator on the suction side of the compressor via four capillary tubes.

The present invention will be explained below with reference to the drawings showing one embodiment thereof.

1 is an indoor unit, 2 is an outdoor unit, and 3°3' is a refrigerant piping unit.

4 is a compressor, 5 is a four-way valve for switching between cooling and heating, 6 is an indoor heat exchanger, 7 is a gas side branch pipe provided at one end of each of a plurality of divided circuits for dividing the refrigerant flowing through the indoor heat exchanger 6, 8 1 is a first capillary tube directly connected to the other end of each of the plurality of divided circuits of the indoor heat exchanger 6, 9 is a transistor repeater, 17 is an outdoor heat exchanger, and 18 is an outdoor heat exchanger. a gas side branch pipe provided at one end of each of the plurality of divided circuits for dividing the refrigerant flowing through the outdoor heat exchanger 17; a second capillary tube 19 directly connected to the other end of each of the plurality of divided circuits of the outdoor heat exchanger 17; 20 is a distributor, 21 is a check valve, 22 is a capillary tube exclusively for heating, and 23 is a first liquid receiver, and the check valve 21 and the capillary tube 22 exclusively for heating are branched from the sample repeater 20 to receive liquid respectively. It is connected to the container 23.

A subcooling heat exchanger 24 is disposed between the liquid receiver 23 and the distributor 9.

10 is an accumulator arranged on the suction side of the compressor 4.

16.16' and 25.25' are joints, and 12 is a second liquid receiver which is connected to the taste repeater 9 via the solenoid valve 11.

13 is a third capillary tube for draining liquid led out from the lower part of the second liquid receiver 12, and 14 is a gas draining pipe led out from the upper part of the second liquid receiver 12. The third capillary tube 13 and the gas venting pipe 14 are joined together and connected to the accumulator 10 via the fourth capillary tube 15.

To explain the operation of the above refrigerant circuit configuration, by setting the four-way cooling/heating switching valve 5 so that the discharge gas of the compressor 4 flows to the indoor heat exchanger 6 during heating operation,
When the high-temperature, high-pressure gas is condensed and liquefied in the indoor heat exchanger 6, a heating effect is performed.

This condensed and liquefied refrigerant liquid is subjected to the first throttling and pressure reduction in the first capillary tube 8, and then to the distributor 9.
．． Subcooling heat exchanger 24 via joint 16.25
After passing through the first liquid receiver 23, a second throttling depressurization is performed in the capillary tube 22 dedicated to heating, and the liquid is transferred from the IJ computer 20 to the plurality of divided circuits of the outdoor heat exchanger 17. A second capillary tube 19 directly connected to one end of each circuit divides the flow evenly to each circuit, and performs tertiary throttling and pressure reduction to enable effective heat exchange.
It is evaporated in the outdoor heat exchanger 17 and sucked into the compressor 4.

During normal heating operation, the solenoid valve 11 is closed and the refrigerant flows only through the main circuit.

Next, in the case of heating operation at a high outside temperature, the heating load decreases as the outside temperature increases, but the heating capacity increases, so the discharge pressure and discharge temperature of the compressor 4 increase.

Therefore, the amount of refrigerant flowing through the main circuit is reduced by opening the solenoid valve 11 and guiding the medium-pressure refrigerant, which has been first throttled and depressurized in the first capillary tube 8, to the second liquid receiver 12 and storing it. This results in a relatively insufficient state, and as a result, the discharge pressure of the compressor 4 can be reduced.

On the other hand, since the amount of refrigerant to the outdoor heat exchanger 17, which is an evaporator, decreases, the amount of refrigerant flows from the outdoor heat exchanger 17 to the accumulator 10.
Although the degree of superheating of the refrigerant increases, the gas refrigerant is led out from the upper gas vent pipe 14 of the second liquid receiver 12, and a part of the refrigerant liquid is led out from the lower third capillary tube 13 for liquid removal. Since the degree of superheat of the refrigerant sucked into the compressor 4 is adjusted by adjusting the decompression flow rate in the capillary tube 15 and causing the refrigerant to flow into the accumulator 10, an increase in the discharge temperature of the compressor 4 can be prevented.

Therefore, the discharge pressure and discharge temperature of the compressor 4 can be kept below a predetermined value over a wide outside temperature range.

In addition, the second liquid receiver 12 has a structure that is connected to a medium pressure close to high pressure as described above, and gas is removed from the gas removal pipe 14 in the upper part, and a portion is removed by the third capillary tube 13 for liquid removal in the lower part. Since the liquid is drained, it is possible to effectively store the refrigerant liquid in the second liquid receiver 12.

Next, in the case of heating operation at low outside temperatures, when frost begins to adhere to the outdoor heat exchanger 17, which acts as an evaporator, a detection device such as a timer switches the four-way valve 5 to reverse cycle defrost operation. The solenoid valve 11 is opened.

As a result, the high-temperature, high-pressure refrigerant gas discharged from the compressor 4 flows into the outdoor heat exchanger 17 and is condensed and liquefied, thereby melting the frost.

At this time, since the solenoid valve 11 is open, the second
Capillary tube 19 to first capillary tube 8
The refrigerant in the intermediate-pressure pipe between the two flows into the second liquid receiver 12, and the suction circuit to the compressor 4 becomes a two-system path connecting the indoor heat exchanger 6 and the second liquid receiver 12. Therefore, the refrigerant condensed and liquefied in the outdoor heat exchanger 17 flows smoothly and does not accumulate in the outdoor heat exchanger 17, and the high temperature and high pressure refrigerant gas from the compressor 4 is transferred to the outdoor heat exchanger 17. Throughout the area,
Defrosting can be performed effectively in a short time by effectively exchanging heat.

In addition, since the residual amount of condensed and liquefied refrigerant in the outdoor heat exchanger 17 during defrosting operation is small, the compressor 4 in wet operation is
The occurrence of troubles can be prevented.

As described above, according to the present invention, by opening the solenoid valve during heating operation at high outside temperatures, the increase in the discharge pressure and discharge temperature of the compressor can be suppressed, and heating operation can be performed within predetermined values. This prevents thermal decomposition of the refrigerant, changes in viscosity and deterioration of the lubricating oil in the compressor, and prevents burnout of the compressor body.

In addition, by opening the solenoid valve during defrosting operation, the refrigerant in the outdoor heat exchanger can be smoothly flowed out, allowing effective heat exchange without accumulating the refrigerant in the outdoor heat exchanger. Defrosting time can be shortened, and damp operation can be prevented when switching to the heating cycle after defrosting operation is completed.
This has many effects, such as preventing damage to compressor valves and gaskets, as well as preventing oil leakage.

[Brief explanation of the drawing]

The figure is a refrigerant circuit diagram of a heating and cooling device showing an embodiment of the present invention. 4... Compressor, 5... Four-way valve for switching between cooling and heating, 6... Indoor heat exchanger, 8...
1st capillary tube, 10...Accumulator, 11...Solenoid valve, 12...2nd
Liquid receiver, 13...Third capillary tube for liquid drainage, 14...Pipe for gas venting, 15...
... Fourth capillary tube, 17... Outdoor heat exchanger, 19... Second capillary tube.

Claims (1)

[Scope of claim for utility model registration] Compressor, four-way valve for switching between cooling and heating, and indoor heat exchanger. Throttle mechanism, outdoor heat exchanger, four-way valve for switching between heating and cooling,
The accumulator and the compressor are sequentially connected in an annular manner, and the throttling mechanism has at least two stages of a first capillary tube on the indoor heat exchanger side and a second capillary tube on the outdoor heat exchanger side. A second liquid receiver is arranged as a capillary tube via a solenoid valve from the first capillary tube, and a gas vent pipe led out from the upper part of the liquid receiver and a liquid drain pipe led out from the lower part of the liquid receiver. A heating and cooling system in which a third capillary tube is joined to the accumulator on the suction side of the compressor via a fourth capillary tube.