JPH08166172A - Refrigerating equipment - Google Patents

Abstract

PURPOSE: To enable sure liquefaction of a nonazeotropic mixture refrigerant and also lowering of a condensation pressure and thereby to improve a refrigerating capacity by providing heat exchange parts conducting heat exchange between the refrigerant flowing from a condenser to a liquid receiver and the refrigerant flowing from an evaporator to a compressor. CONSTITUTION: In refrigerating equipment having a compressor 1, a condenser 4 condensing a compressed nonazeotropic mixture refrigerant by external air, a liquid receiver 5, a pressure reducing unit 7, an evaporator 8, etc., there are provided a first heat exchange part 10 wherein a suction piping 13 on the outlet side of the evaporator 8 is laid along piping 12 between the condenser 4 and the liquid receiver 5, and besides, a second heat exchange part 11 wherein the suction piping 13 is laid likewise along a piping 14 between a drier 6 and a capillary tube 7. Thereby the nonazeotropic mixture refrigerant from the condenser 4 is cooled by the nonazeotropic mixture refrigerant flowing through the piping 13 in the first heat exchange part 10 and having a lower temperature than the external air. Besides, the liquid refrigerant coming out from the drier 6 is supercooled in the second heat exchange part 11 likewise by the refrigerant in the piping 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus using a non-azeotropic mixed refrigerant, which is intended to surely liquefy the non-azeotropic mixed refrigerant and to reduce the condensing pressure.

[0002]

2. Description of the Related Art Conventional refrigerants include dichlorodifluoromethane (hereinafter referred to as R-12) and an azeotropic refrigerant R-1.
R-500 consisting of 2 and 1,1-difluoroethane was used. The boiling point of R-12 is -29.65 ° C at atmospheric pressure.
The boiling point of R-500 was −33.45 ° C., which was suitable for ordinary refrigeration equipment.

However, due to their high ozone depletion potential, the above refrigerants destroy the ozone layer when they reach the ozone layer above the earth by being released into the atmosphere. The destruction of the ozone layer is caused by the chlorine group in the refrigerant. Therefore, as these alternative refrigerants, a refrigerant having a low chlorine group content, a chlorine group-free refrigerant, or a mixture thereof is considered. Examples of the refrigerant having a low chlorine group content include chlorodifluoromethane (HCFC-2
2, hereinafter referred to as R22), 2-chloro-1,1,1,2
-Tetrafluoroethane (HCFC-124, hereinafter R1
24), and as a refrigerant containing no chlorine group,
For example, difluoromethane (HFC-32, hereinafter R32), pentafluoroethane (HFC-125, hereinafter R125), 1,1-difluoroethane (HFC
-152a, hereinafter referred to as R152a), 1,1,1,2
-Tetrafluoroethane (HFC-134a, hereinafter R1
34a). The boiling point of this R22 is at atmospheric pressure-
At 40.82 ° C, the boiling point of R124 is-12.03 ° C,
The boiling point of R32 is -51.7 ° C, and the boiling point of R125 is-
At 48.5 ° C., the boiling point of R152a is −52.0 ° C.
The boiling point of 134a is −26.5 ° C.

As the mixed refrigerant, for example, R407A in which R32, R125, and R134a are mixed at 20:40:40, R407B in which R32, R125, and R134a are mixed at 10:70:20, or R2.
There is R401A which is a mixture of 2 and R124 and R152a at 52:33:15. R407A, R407B and R4
01A is a non-azeotropic mixed refrigerant, the boiling point of R407A is -45.4 ° C in the atmosphere, the dew point is -38.8 ° C, and R4A is R4A.
07B has a boiling point of -47.4 ° C and a dew point of -42.8 ° C, and R401A has a boiling point of -33.1 ° C and a dew point of -26.
6 ° C.

As a refrigerating device using these non-azeotropic mixed refrigerants, there is, for example, Japanese Patent Publication No. 5-45867. This constitutes a cooling cycle with a compressor, a condenser, an electric expansion valve, and an evaporator, and adds a heat exchanger for exchanging heat between a suction refrigerant of the compressor and a high-pressure liquid refrigerant. Then, the high-temperature and high-pressure refrigerant compressed by the compressor is liquefied by the condenser, and the high-pressure liquid refrigerant is supercooled by the heat exchanger and sent to the evaporator. A low-temperature liquid refrigerant passes through the evaporator and exchanges heat with the outside air to cool the outside air.

[0006]

However, since the single refrigerant and the azeotropic mixed refrigerant have no temperature gradient in the latent heat change region, a sufficient difference between the refrigerant temperature on the outlet side of the condenser and the outside air temperature can be ensured. Condensation is possible only by heat exchange with the outside air in the condenser, but since the non-azeotropic mixed refrigerant has a different boiling point and dew point and a temperature gradient in the latent heat change region, there is a difference between the refrigerant temperature on the outlet side of the condenser and the outside air temperature. Since the sufficient amount cannot be secured, the non-azeotropic mixed refrigerant was not cooled much only by heat exchange with the outside air in the condenser. Therefore, the condensing pressure becomes higher than that in the case of using a single refrigerant, and the pressure at the discharge side of the condenser and the compressor becomes higher. That is, since the discharge pressure of the compressor is high, the volumetric efficiency is low, and the capacity of the compressor is low.
As a result, the efficiency of the entire refrigeration system was poor.

Further, since a refrigerant having a low boiling point is difficult to liquefy, the composition ratio of the liquefied non-azeotropic mixed refrigerant may be different from the composition ratio of the non-azeotropic mixed refrigerant at the time of setting. Therefore, when a liquid refrigerant having a composition ratio different from that at the time of setting passes through the evaporator, the boiling point and the dew point of the non-azeotropic mixed refrigerant are different, which makes it impossible to reliably control the temperature of the refrigeration system.

Therefore, an object of the present invention is to reliably liquefy a non-azeotropic mixed refrigerant for efficient refrigerating operation.

[0009]

In order to solve the above problems, the invention of claim 1 is a compressor for compressing a refrigerant, a condenser for condensing the refrigerant compressed by the compressor with outside air, and A receiver for storing the refrigerant from the condenser, and a decompressor for decompressing the refrigerant from the receiver,
In a refrigerating apparatus including an evaporator that evaporates the refrigerant from the decompressor, heat for exchanging heat between the refrigerant flowing from the condenser to the liquid receiver and the refrigerant flowing from the evaporator to the compressor. It is a refrigerating device provided with an exchange section.

The invention of claim 2 is a compressor for compressing a refrigerant, a condenser for condensing the refrigerant compressed by the compressor by the outside air, and a receiver for storing the refrigerant from the condenser. And a decompressor that decompresses the refrigerant from the liquid receiver, and an evaporator that includes an evaporator that evaporates the refrigerant from the pressure reducer, from the refrigerant and the evaporator in the liquid receiver. It is a refrigerating device provided with a heat exchange part for exchanging heat with the refrigerant flowing through the compressor.

A third aspect of the invention is the refrigerating apparatus according to the first or second aspect, wherein the refrigerant is a non-azeotropic mixed refrigerant.

[0012]

According to the refrigerating apparatus of the first aspect, heat is exchanged between the pipe on the outlet side of the evaporator and the pipe between the condenser and the liquid receiver. Then, a refrigerant having a temperature lower than that of the outside air flows in the pipe on the outlet side of the evaporator, and cools the high temperature refrigerant in the pipe between the condenser and the liquid receiver.

In the refrigerating apparatus of the second aspect, the pipe on the outlet side of the evaporator is arranged around the liquid receiver. Then, a refrigerant having a temperature lower than that of the outside air flows in the pipe on the outlet side of the evaporator and circulates around the liquid receiver to cool the liquid receiver. Then, the gas refrigerant in the liquid receiver is cooled and liquefied.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a refrigeration circuit diagram of the present invention. A non-azeotropic mixed refrigerant is used as the refrigerant of this refrigeration circuit. As this non-azeotropic mixed refrigerant, there is R407C in which R32, R125 and R134a are mixed at a ratio of 23:25:52, especially for a low temperature refrigerator, and this refrigerant was used. Reference numeral 1 is a compressor for compressing a non-azeotropic refrigerant, which sucks a gas refrigerant from a suction port 2 and discharges it from a discharge port 3. 4 is a condenser,
The outside air is sent to the tube through which the gas refrigerant passes by the fan 4a. Here, the gas refrigerant is cooled and condensed by outside air while passing through the condenser 4. A liquid receiver 5 stores a liquid refrigerant therein. The liquid receiver 5 has a refrigerant inlet on the upper side and a refrigerant outlet on the lower side, and only the liquid refrigerant is discharged from the refrigerant outlet. Reference numeral 6 denotes a dryer having a desiccant filled therein, which removes water in the liquid refrigerant. A capillary tube 7 decompresses the liquid refrigerant from which water has been removed by the dryer 6. Reference numeral 8 denotes an evaporator, which has a cooling function by absorbing the heat of the outside air by the liquid refrigerant. An accumulator 9 stores the liquid refrigerant that cannot be completely evaporated in the evaporator 8 and returns only the gas refrigerant to the compressor 1.

Reference numeral 10 is a first heat exchange section, and 11 is a second heat exchange section. FIG. 2 is a perspective view of the first heat exchange unit 10 and the second heat exchange unit 11. The first heat exchange unit 10 is fixed to the pipe 12 between the condenser 4 and the liquid receiver 5 along with the suction pipe 13 on the outlet side of the evaporator 8, and the second heat exchange unit 11
Is a pipe 14 between the dryer 6 and the capillary tube 7.
The suction pipe 13 is attached to and fixed. In addition,
The configuration of the first heat exchange unit 10 may be any configuration as long as the non-azeotropic mixed refrigerant in the pipe 12 and the suction pipe 13 can exchange heat, and is not limited to the embodiment. Further, the heat exchange section that is a feature of the present invention is the first heat exchange section 10.

Next, the operation of this refrigeration circuit will be described. The compressor 1 compresses the gas refrigerant sucked from the suction port 2 and discharges it from the discharge port 3. This non-azeotropic mixed refrigerant is a high temperature and high pressure gas refrigerant. The non-azeotropic mixed refrigerant compressed by the compressor 1 is cooled by the outside air in the condenser 4 and condensed. Since the non-azeotropic mixed refrigerant has a different boiling point and dew point, a temperature gradient occurs in the latent heat change region. Therefore, it is not cooled very much by cooling with the outside air in the condenser 4, and a refrigerant having a particularly low dew point in a part of the non-azeotropic mixed refrigerant is not liquefied but exists as a gas refrigerant. Further, since a refrigerant having a high dew point is easily liquefied and a refrigerant having a low dew point is hard to liquefy, many refrigerants have a high dew point in the liquid refrigerant and many refrigerants have a low dew point in the gas refrigerant. The non-azeotropic mixed refrigerant in which the liquid refrigerant and the gas refrigerant are mixed passes through the first heat exchange section 10. Since the non-azeotropic mixed refrigerant in the suction pipe 13 of the first heat exchange unit 10 is lower in temperature than the outside air, the non-azeotropic mixed refrigerant from the condenser 4 is cooled. At this time, since the gas refrigerant condenses, the composition ratio of the liquid refrigerant becomes close to the set value. Further, since the amount of the liquefied refrigerant increases, the pressures of the discharge port 3 side of the compressor 1 and the condenser 4 decrease, and the compressor 1
The discharge pressure of is also reduced. Therefore, the volume effect is increased, the capacity of the compressor 1 is improved, and the coefficient of performance of the entire refrigeration circuit is improved.

The non-azeotropic mixed refrigerant is temporarily stored in the liquid receiver 5, the gas refrigerant is reserved, and only the liquid refrigerant is sent to the dryer 6. After removing the moisture by the dryer 6, the liquid refrigerant is sent to the second heat exchange section 11. In the second heat exchange section 11, the liquid refrigerant is supercooled by the non-azeotropic mixed refrigerant in the suction pipe 13. The liquid refrigerant cooled by the second heat exchange unit 11 is decompressed by the capillary tube 7 and easily evaporated. In the evaporator 8, the liquid refrigerant exchanges heat with the outside air to cool the outside air. At this time, the liquid refrigerant in the evaporator 8 absorbs external heat to become a gas refrigerant, but its temperature is lower than that of the outside air. The non-azeotropic mixed refrigerant that has passed through the evaporator 8 is suction pipe 1
It passes through the inside of 3 and passes the 1st heat exchange part 10 and the 2nd heat exchange part 11. Although the liquid refrigerant remains in this non-azeotropic mixed refrigerant, the remaining liquid refrigerant is evaporated by performing heat exchange in the first heat exchange unit 10 and the second heat exchange unit 11. The accumulator 9 sends only the gas refrigerant to the compressor 1 to store the liquid refrigerant.

FIG. 2 shows another embodiment of the first heat exchange section 10 (embodiment of claim 2). This has a suction pipe 13 arranged spirally around the liquid receiver 5. At this time, the liquid receiver 5 is cooled by the low-temperature non-azeotropic mixed refrigerant in the suction pipe 13. Therefore, the gas refrigerant retained in the liquid receiver 5 is condensed.

[0019]

According to the present invention, since the refrigerant between the condenser and the liquid receiver is cooled by the refrigerant sucked into the compressor, the pressure on the discharge side of the compressor is lowered. Therefore, the discharge pressure of the compressor is reduced, the volumetric efficiency is increased, and the capacity of the compressor is improved. Therefore, the coefficient of performance of the refrigerator is improved. Further, since the gas refrigerant that has not been completely liquefied in the condenser is cooled and liquefied at a temperature lower than the outside air, the composition ratio of the liquid refrigerant does not change from the set value, and reliable temperature control can be performed. Further, it is possible to promote the evaporation of the refrigerant that cannot be completely evaporated in the evaporator, and the refrigeration cycle can be efficiently circulated.

[Brief description of drawings]

FIG. 1 is a refrigeration circuit diagram.

FIG. 2 is a perspective view of a heat exchange section.

FIG. 3 is a perspective view of another heat exchange unit.

[Explanation of symbols]

 1 Compressor 4 Condenser 5 Liquid Receiver 7 Capillary Tube 8 Evaporator 10 First Heat Exchanger 13 Suction Pipe

Claims (3)

[Claims] 1. A compressor for compressing a refrigerant, a condenser for condensing the refrigerant compressed by the compressor with outside air, and a receiver for storing the refrigerant from the condenser.
In a refrigeration apparatus including a decompressor that decompresses the refrigerant from the liquid receiver and an evaporator that evaporates the refrigerant from the pressure reducer, the refrigerant and the evaporation that flow from the condenser to the liquid receiver. A refrigerating apparatus comprising a heat exchange section for exchanging heat with the refrigerant flowing from the container to the compressor. 2. A compressor for compressing a refrigerant, a condenser for condensing the refrigerant compressed by the compressor with outside air, and a receiver for storing the refrigerant from the condenser.
In a freezing device comprising a decompressor for decompressing the refrigerant from the receiver and an evaporator for evaporating the refrigerant from the decompressor, the refrigerant in the receiver and the compression from the evaporator A refrigerating apparatus comprising a heat exchange section for exchanging heat with the refrigerant flowing through the machine. 3. The refrigerating apparatus according to claim 1, wherein the refrigerant is a non-azeotropic mixed refrigerant.