CN111435041A

CN111435041A - Compression type refrigerating system and refrigerating and freezing device

Info

Publication number: CN111435041A
Application number: CN201910028144.0A
Authority: CN
Inventors: 赵向辉; 田红荀; 梁静娜; 孙永升
Original assignee: Qingdao Haier Smart Technology R&D Co Ltd
Current assignee: Qingdao Haier Smart Technology R&D Co Ltd
Priority date: 2019-01-11
Filing date: 2019-01-11
Publication date: 2020-07-21

Abstract

The invention provides a compression type refrigerating system and a refrigerating and freezing device, wherein the compression type refrigerating system comprises a gas-liquid separator which is arranged between an outlet of an evaporator and a gas return pipe leading to a compressor, and the gas-liquid separator comprises: the cylinder body defines a separation cavity, and liquid refrigerant discharged by the evaporator is settled at the lower part of the separation cavity to form a liquid storage area; the outlet pipe is communicated with the upper part of the separation cavity, is connected to the gas return pipe and is used for discharging the gaseous refrigerant at the upper part of the separation cavity to the gas return pipe; the head end of the liquid return pipe is arranged in the liquid storage area, extends out of the cylinder body and is connected to the outlet pipe, so that the mixed liquid of the refrigeration oil and the liquid refrigerant in the liquid storage area is discharged to the gas return pipe; and at least one part of the capillary tube is attached to the air return pipe or is arranged in the air return pipe in a penetrating way, wherein the liquid return pipe is constructed to ensure that the liquid refrigerant entering the air return pipe is completely gasified, and simultaneously, the content of the gaseous refrigerant in the capillary tube is reduced, thereby reducing the eruption noise at the position.

Description

Compression type refrigerating system and refrigerating and freezing device

Technical Field

The invention relates to the technical field of refrigeration, in particular to a compression type refrigeration system and a refrigerating and freezing device.

Background

The small compression refrigerating system mainly includes compressor, condenser, throttling element and evaporator component, the compressor is the power of refrigerating circulation, it is dragged by the motor and rotates ceaselessly, in time take out the interior vapour of evaporator, maintain low temperature low pressure, still improve the pressure and the temperature of refrigerant vapour through the compression action, create the condition that transfers the heat of refrigerant vapour to external environment medium. The condenser takes away heat of high-temperature and high-pressure refrigerant vapor from the compressor by using an environmental cooling medium (such as air or water), so that the high-temperature and high-pressure refrigerant vapor is cooled and condensed into refrigerant liquid with high pressure and normal temperature. The high-pressure normal-temperature refrigerant liquid passes through the throttling element to obtain a low-temperature low-pressure refrigerant, and then is sent into the evaporator for heat absorption and evaporation. The throttled low-temperature and low-pressure refrigerant liquid is evaporated (or boiled) in the evaporator to become steam, and the heat of the cooled substance is absorbed, so that the temperature of the substance is reduced, and the aim of refrigerating the surrounding environment is fulfilled.

Compression refrigeration systems also have a number of additional components, for example the evaporator outlet is also often provided with a gas-liquid separator (or referred to as a receiver). The gas-liquid separator is a common accessory component in refrigeration systems where the primary function is to separate and preserve refrigerant liquid at the evaporator exit to prevent compressor slugging. The gas-liquid separator can temporarily store redundant refrigerant liquid, and prevent the redundant refrigerant from flowing to a crankcase of the compressor to cause dilution of oil and even liquid impact. Therefore, when the gas-liquid separator is arranged in the refrigeration system, a smaller oil return hole is generally arranged at the bottom of the outlet pipe (the ratio of the sum of the opening areas of the oil return holes to the inner cross-sectional area of the outlet pipe is generally not more than 1.5%, and the limit condition is generally not more than 2%), so that liquid refrigerant is prevented from flowing back to the compressor.

In the case of compression-type refrigeration systems for use in refrigerators and freezers, capillary tubes are often used as throttling elements. In the refrigerating system, the outlet of the capillary tube has part of flash gas refrigerant besides liquid refrigerant, the mass percentage can be about 20%, and the flow velocity of the refrigerant at the outlet of the capillary tube is large and even can reach 200m/s due to the fact that the gaseous refrigerant accounts for more and the specific volume of the gaseous refrigerant is smaller, so that the noise and sound quality at the outlet of the capillary tube are poor, and poor user experience is caused.

In addition, the refrigerant at the outlet of the evaporator usually has a certain superheat, and the dryness of the refrigerant in the evaporator near the outlet section of the evaporator is also higher, so that the heat exchange coefficient in the evaporator near the outlet section is lower, and the power consumption is increased.

The above technical problem has not been solved in an effective manner in the prior art.

Disclosure of Invention

It is an object of the present invention to provide a compression-type refrigeration system and a refrigerating and freezing apparatus which solve at least any one of the above-mentioned problems.

A further object of the present invention is to reduce the amount of gaseous refrigerant at the outlet of the capillary tube and to reduce the noise of the spray.

It is another further object of the present invention to increase the heat exchange efficiency of the evaporator.

In particular, the present invention provides a compression refrigeration system, comprising a compressor, a condenser, a capillary tube, an evaporator connected in sequence by a pipeline, and further comprising: a gas-liquid separator disposed between the evaporator outlet and a return pipe leading to the compressor, the gas-liquid separator comprising: the cylinder body defines a separation cavity, and liquid refrigerant discharged by the evaporator is settled at the lower part of the separation cavity to form a liquid storage area; the outlet pipe is communicated with the upper part of the separation cavity, is connected to the gas return pipe and is used for discharging the gaseous refrigerant at the upper part of the separation cavity to the gas return pipe; the head end of the liquid return pipe is arranged in the liquid storage area, extends out of the cylinder body and is connected to the outlet pipe, so that the mixed liquid of the refrigeration oil and the liquid refrigerant in the liquid storage area is discharged to the gas return pipe; and at least one part of the capillary tube is attached to the air return tube or is arranged in the air return tube in a penetrating mode, wherein the liquid return tube is constructed to enable liquid refrigerant entering the air return tube to exchange heat with refrigerant in the capillary tube to be completely gasified, and meanwhile the content of gaseous refrigerant in the capillary tube is reduced.

Optionally, a liquid return pipe extends upwardly from the head end thereof and extends from the upper portion of the barrel to be connected to the outlet pipe.

Optionally, the liquid return pipe extends downwards from the head end of the liquid return pipe, extends from the bottom of the barrel and then is connected to the outlet pipe.

Optionally, the ratio of the inner cross-sectional area of the liquid return pipe to the inner cross-sectional area of the outlet pipe is 2% to 10%.

Optionally, the ratio of the inner cross-sectional area of the liquid return pipe to the inner cross-sectional area of the outlet pipe is 3% to 10%.

Optionally, the ratio of the inner cross-sectional area of the liquid return pipe to the inner cross-sectional area of the outlet pipe is 4% to 10%.

Optionally, the gas-liquid separator further comprises: and the inlet pipe is connected with the outlet of the evaporator and extends into the upper part of the separation cavity from the cylinder body.

Optionally, the portion of the inlet tube within the separation chamber is obliquely disposed with the direction of inclination facing away from the outlet tube.

Optionally, a dry filter is further disposed between the condenser and the capillary tube.

According to another aspect of the present invention, there is also provided a refrigeration and freezing apparatus, comprising: the compression type refrigerating system is characterized in that an evaporator of the compression type refrigerating system is used for providing cold energy for the refrigerating and freezing device.

The compression type refrigerating system is additionally provided with the liquid return pipe, and the liquid refrigerant at the lower part of the separation cavity is discharged to the gas return pipe along with the refrigerant oil through the liquid return pipe. The refrigerant of capillary and the refrigerant of muffler carry out the heat transfer, reduce the gaseous refrigerant's of the export of capillary content to reduce the eruption noise of this department, promoted the sound quality of this department.

Further, in the compression type refrigeration system, the liquid refrigerant in the liquid storage area at the bottom of the gas-liquid separator is discharged into the gas return pipe and is evaporated in the heat exchange process with the refrigerant in the capillary tube, so that the refrigerant at the outlet of the evaporator is in a gas-liquid two-phase state, the heat exchange efficiency of the evaporator is improved, and the whole power consumption can be reduced.

The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a schematic view of a compression refrigeration system according to one embodiment of the present invention;

FIG. 2 is an enlarged view of a gas-liquid separator in a compression refrigeration system according to an embodiment of the present invention;

FIG. 3 is a schematic view of a compression refrigeration system according to another embodiment of the present invention;

figure 4 is a basic principle schematic of a pressure-enthalpy diagram;

FIG. 5 is a schematic illustration of a comparative arrangement of a compression refrigeration system according to one embodiment of the present invention;

FIG. 6 is a pressure-enthalpy diagram for a compression refrigeration system of a comparative scheme;

figure 7 is a pressure enthalpy diagram for a compression type refrigeration system according to one embodiment of the present invention; and

fig. 8 is a schematic block diagram of a refrigeration freezer in accordance with one embodiment of the invention.

Detailed Description

Figure 1 is a schematic diagram of a compression refrigeration system 100 according to one embodiment of the present invention. Figure 2 is an enlarged view of a gas-liquid separator 150 in a compression refrigeration system 100 according to one embodiment of the present invention. The compression refrigeration system 100 may generally include: the compressor 110, the condenser 120, the capillary tube 130, and the evaporator 140 are also referred to as four major components of the refrigeration system, and the working principle of the refrigerant circulating through the four major components is well known to those skilled in the art and will not be described herein.

The compression refrigeration system 100 of the present embodiment further includes: the gas-liquid separator 150 is disposed downstream of the evaporator 140, i.e., between an outlet of the evaporator 140 and a return air pipe 170 leading to the compressor 110, for separating the refrigerant discharged from the evaporator. The gas-liquid separator 150 defines a separation chamber for allowing the liquid refrigerant discharged from the evaporator 140 to settle in a lower portion of the separation chamber 154.

The gas-liquid separator 150 may include: a cylinder 151, an inlet pipe 152, an outlet pipe 153, and a liquid return pipe 158, wherein the cylinder 151 defines a separation chamber 154; the separation chamber 154 is used to settle the liquid refrigerant discharged from the evaporator 140 at a lower portion thereof.

The inlet pipe 152 is connected to an outlet of the evaporator 140 and extends from the cylinder 151 to an upper portion of the separation chamber 154, so that the refrigerant is discharged from the upper portion of the cylinder 151 to the separation chamber 154 and the liquid refrigerant is settled in a lower portion of the separation chamber 154.

And an outlet pipe 153 communicating with an upper portion of the separation chamber 154 and connected to the return pipe 170 for discharging the gaseous refrigerant at the upper portion of the separation chamber 154 toward the return pipe 170.

The liquid return pipe 158 is disposed in the liquid storage region at a head end thereof, extends out of the cylinder 151, and is connected to the outlet pipe 151, so as to discharge a mixed liquid of the refrigerant oil and the liquid refrigerant in the liquid storage region to the gas return pipe 170.

In order to prevent the refrigerant of the inlet pipe 152 from directly entering the outlet pipe 153, a portion of the inlet pipe 152 in the separation chamber is inclined and directed away from the outlet pipe 153. The outlet pipe 153 may be positioned at an upper portion of the circumferential wall of the cylinder 151 at the opening of the cylinder 151.

At least a portion of the capillary tube 130 is attached to the muffler 170 or passes through the muffler 170, wherein the liquid return pipe 158 is configured to completely vaporize the liquid refrigerant entering the muffler 170 by exchanging heat with the refrigerant in the capillary tube 130, and simultaneously reduce the content of the gaseous refrigerant in the capillary tube 130.

The liquid return pipe 158 may be configured to completely vaporize the liquid refrigerant entering the gas return pipe 170 by exchanging heat with the refrigerant in the capillary tube 130, while reducing the content of the gaseous refrigerant in the capillary tube 130 and ensuring that the refrigerant oil can be returned to the compressor as much as possible.

Through practical tests, the ratio of the inner sectional area of the liquid return pipe 158 to the inner sectional area of the outlet pipe 153 can be in the range of 2% -10%. For example, the ratio of the inner sectional area of the liquid return pipe 158 to the inner sectional area of the outlet pipe 153 may be 3% to 10%, and preferably 4% to 10%.

In order to ensure the heat exchange effect, the length of the capillary 130 abutting against the air return pipe 170 or the length of the capillary 130 penetrating into the air return pipe 170 can be increased, so as to ensure sufficient heat exchange.

Because the refrigerant flowing through the capillary tube 130 exchanges heat with the liquid refrigerant mixed in the muffler 170, the gaseous refrigerant is partially or completely liquefied, thereby reducing the gaseous component in the refrigerant at the outlet of the capillary tube 130, reducing the eruption noise at the place, and improving the sound quality at the place.

The refrigerant at the outlet of the evaporator 140 is gas-liquid two-phase, which improves the heat exchange efficiency of the evaporator 140 and reduces the overall power consumption.

A dry filter 160 may also be disposed between the condenser 120 and the capillary tube 130. The filter drier 160 filters impurities and moisture in the refrigerant.

The diameter of the return pipe 158 is also related to the configuration of the return pipe 158, and the return pipe 158 may extend downward from the head end and extend from the bottom of the cylinder 151 to be connected to the outlet pipe 153, i.e. the return pipe 158 has a short length in the separation chamber 154 and a long length extending outside the cylinder 151.

Figure 3 is a schematic diagram of a compression refrigeration system 100 according to another embodiment of the present invention. The compression refrigeration system 100 of this embodiment differs from the embodiment shown in fig. 1 in that a liquid return pipe 158, which extends upward from the head end thereof, protrudes from the upper portion of the cylinder 151 and is connected to the outlet pipe 153. That is, the liquid return pipe 158 has a longer length inside the separation chamber 154 and a shorter length outside the cylinder 151.

The effect verification of the compression-type refrigeration system 100 of the above embodiment with the compression-type refrigeration systems of other schemes proves that the effect is far better than that of other compression-type refrigeration systems. The effects will be described below by a pressure-enthalpy diagram.

Figure 4 is a schematic diagram of the basic principle of the pressure-enthalpy diagram. In the pressure-enthalpy diagram, the ordinate is the logarithmic value lgP of the absolute pressure (in Bar) and the abscissa is the specific enthalpy h (in kJ/kg).

Ka is a saturated liquid line, and any point on the line is saturated liquid with corresponding pressure; kb is a saturated steam line, and the state of any point on the Kb line is a saturated steam state, or called dry steam. The critical point K is the intersection point of the saturated liquid line Ka and the saturated vapor line Kb, at which point K the difference between the liquid state and the gas state of the refrigerant disappears.

The left side of Ka is a supercooled liquid zone Z34, and the temperature of a refrigerant in the supercooled liquid zone Z34 is lower than the saturation temperature under the same pressure; the right side of Kb is a superheated steam zone Z36, and the temperature of steam in the superheated steam zone Z36 is higher than the saturation temperature under the same pressure; between Ka and Kb is a wet steam zone Z35, i.e. a gas-liquid coexisting zone. The refrigerant in the gas-liquid coexisting region is in a saturated state, and the pressure and the temperature are in one-to-one correspondence.

The diagram includes four parameter lines, i.e., an isobaric line L31 (parallel to the abscissa, pressure at each point on the same isobaric line is equal), an isenthalpic line L30 (perpendicular to the abscissa, working medium on the same isenthalpic line has equal enthalpy regardless of the state), an isotherm L33 (the isotherm varies in different regions and has different shapes, the isotherm is almost perpendicular to the abscissa in the supercooling region, the isotherm is a horizontal line parallel to the abscissa in the wet steam region Z35, the isotherm is a steeply curved line toward the lower right in the superheated steam region Z36), and an isothermicity line L32 (starting from a critical point K, a line connecting the same dryness points in the wet steam region Z35 is the isothermicity line L32, and only the wet steam region Z35 exists, wherein dryness is the mass percent of dry steam contained in each kilogram of wet steam).

Fig. 5 is a schematic view of a comparative version of compression refrigeration system 100 according to one embodiment of the present invention, compression refrigeration system 400 in this comparative version differing from compression refrigeration system 100 in this embodiment only in the absence of return line 158.

Fig. 6 is a pressure-enthalpy diagram of a compression-type refrigeration system 400 of a comparative embodiment, in which the abscissa h represents the enthalpy value (kJ/kg) of the refrigerant, the ordinate lgP represents the logarithm of the absolute pressure (in bar) of the refrigerant, the leftmost curve represents the saturated liquid-state refrigerant line L51, the rightmost curve represents the saturated gaseous-state refrigerant line L52, and 9 curves between the two lines represent equal dryness lines (i.e., the curves having dryness x of 0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8, and 0.9, respectively).

The process of the refrigerant in the compressor 410 is from point 51 to point 52 on the pressure-enthalpy diagram, the state of the refrigerant entering the compressor 410 is point 51, and the state of the refrigerant discharged from the compressor 410 is point 52, i.e. the low-temperature and low-pressure superheated gaseous refrigerant is compressed by the compressor 410 to become a high-temperature and high-pressure superheated gaseous refrigerant;

after the refrigerant is output from the compressor 410, the process in the condenser 420 is from point 52 to point 53, and due to the heat release effect of the condenser 420, the high-temperature and high-pressure superheated gaseous refrigerant is changed into a high-pressure liquid refrigerant (having a smaller supercooling degree);

then, the refrigerant enters the capillary tube 430 to be throttled and decompressed (the pressure is reduced from the pressure at the point 53 to the pressure at the point 54), and exchanges heat with the refrigerant in the return air tube 470 in the capillary tube 430 (the enthalpy value is reduced from the enthalpy value at the point 53 to the enthalpy value at the

point

54, 53 to 53 'are equal enthalpy lines, and the enthalpy difference between 54 and 53' is equal to the enthalpy difference between 55 and 51);

the refrigerant output from the capillary tube 430 enters the evaporator 440, the state point of the inlet of the evaporator 440 is point 54, the refrigerant absorbs heat in the evaporator 440 and evaporates, and then enters the gas-liquid separator 450, and the refrigerant states of the outlet of the evaporator 440 and the outlet of the gas-liquid separator 450 are almost the same during stable operation: state point 55 (slightly superheated vapor) then enters the muffler 470 where it exchanges heat with the capillary tube 430 (point 55 to point 51) and then enters the compressor 410 to cycle back and forth.

Fig. 7 is a pressure-enthalpy diagram of the compression-type refrigeration system 100 according to an embodiment of the present invention, in which the abscissa h is an enthalpy value (kJ/kg) of the refrigerant, the ordinate lgP is a logarithmic value (in bar) of an absolute pressure of the refrigerant, the leftmost curve is a saturated liquid-state refrigerant line L61, the rightmost curve is a saturated gaseous-state refrigerant line L62, and 9 curves between the two lines are equal-dryness lines (curves having dryness x of 0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8, and 0.9, respectively).

The refrigerant flowing through the compressor 110 is from a state point 61 to a state point 62 on a pressure-enthalpy diagram, the state of the refrigerant entering the compressor 110 is the point 61, and the state of the refrigerant discharged from the compressor 110 is the point 62, i.e., the low-temperature and low-pressure superheated gaseous refrigerant is compressed by the compressor 110 and becomes a high-temperature and high-pressure superheated gaseous refrigerant.

After the refrigerant is output from the compressor 110, the refrigerant flows from the state point 62 (inlet of the condenser 120) to the state point 63 (outlet of the condenser 120) in the condenser 120, and the high-temperature and high-pressure superheated gaseous refrigerant is changed into a high-pressure liquid refrigerant (having a smaller supercooling degree) due to the heat release of the condenser 120.

Then enters the capillary 130 for throttling and pressure reduction (the pressure is reduced from the pressure of the state point 63 (the inlet of the capillary 130) to the pressure of the state point 64 (the outlet of the capillary 130)), and exchanges heat with the gas-liquid mixed refrigerant in the muffler 170 in the capillary 130 (the enthalpy value is reduced from the enthalpy value of the state point 63 to the enthalpy value of the state point 64, the enthalpy value from the state point 63 to the state point 63 'is an isenthalpic line, and the enthalpy difference from the state point 64 to the state point 63' is equal to the enthalpy difference from the state point 65 to the state point 61).

The refrigerant output from the capillary tube 130 enters the evaporator 140, the state point of the refrigerant at the inlet of the evaporator 140 is point 64, the refrigerant absorbs heat in the evaporator 140 to the state point 65 (gas-liquid mixed state) and then is output from the evaporator 140, and then enters the gas-liquid separator 150, the liquid refrigerant at the bottom of the gas-liquid separator 150 exchanges heat with the capillary tube 130 and evaporates, and then enters the gas-liquid separator 150, the liquid storage area of the gas-liquid separator 150 is provided with a liquid return pipe 158, the refrigerant output from the gas-liquid separator 150 is in a gas-liquid mixed state (state point 65), and then enters the gas return pipe 170 to exchange heat with the refrigerant in the capillary tube 130 (state point 65 to state point 61), and then enters the compressor 110 to reciprocate in a.

As can be seen from a comparison between fig. 6 and fig. 7, the enthalpy value of the state point 64 of the compression refrigeration system 100 of the present embodiment is lower, and the refrigerant at the state point 65 is in a gas-liquid mixed state, so that the enthalpy value at the state point 66 is significantly higher than that at the state point 65.

The enthalpy of the state point 54 is higher in the comparison scheme, mainly because the enthalpy difference between the state points 55 and 51 is limited, the enthalpy of the state point 54 is higher, the dryness of the refrigerant is still higher, and the quality of the eruption noise and the loud sound at the outlet of the capillary 130 is poor.

The embodiment also provides a refrigerating and freezing device. Fig. 8 is a schematic block diagram of a refrigerating and freezing apparatus 70 according to an embodiment of the present invention, the refrigerating and freezing apparatus 70 including: in the compression refrigeration system 100 of any of the embodiments described above, the evaporator 140 of the compression refrigeration system 100 is used to supply cooling energy to the refrigeration chiller 70.

The refrigerating and freezing device 70 is, for example, a refrigerator as a home appliance for keeping food or other articles in a cold state at a constant low temperature. The refrigerating and freezing device 70 may have a box body and a door body. At least one storage compartment with an open front side is defined in the box body, and is generally a plurality of storage compartments, such as a refrigerating compartment, a freezing compartment, a temperature changing compartment and the like. The door body is arranged on the front side of the box body and used for opening and closing the storage compartment. The evaporator 140 of the compression refrigeration system 100 is configured to provide cooling directly or indirectly to the storage compartment. For example, when the refrigeration and freezing apparatus 70 is a compression-type refrigerator for domestic use, the evaporator 140 may be disposed outside or inside the rear wall of the refrigerator cabinet. When the refrigerating and freezing device 70 is a household compression type air-cooled refrigerator, the refrigerator body is also provided with an evaporator chamber, the evaporator chamber is communicated with the storage compartment through an air path system, an evaporator 140 is arranged in the evaporator chamber, and a fan is arranged at an outlet of the evaporator chamber so as to perform circulating refrigeration on the storage compartment.

Due to the compression-type refrigeration system 100 of the embodiment, the content of the gaseous refrigerant at the outlet of the capillary tube 130 is reduced, so that the eruption noise at the position is reduced, the sound quality at the position is improved, and the heat exchange efficiency of the evaporator 140 is improved. Therefore, the silencing effect and the sound quality of the refrigerating and freezing device are better, and more electricity is saved.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.

Claims

1. The compression type refrigerating system comprises a compressor, a condenser, a capillary tube and an evaporator which are sequentially connected through pipelines, and further comprises: a gas-liquid separator disposed between the evaporator outlet and a return pipe leading to the compressor, the gas-liquid separator comprising:

the cylinder body defines a separation cavity, and liquid refrigerant discharged by the evaporator is settled at the lower part of the separation cavity to form a liquid storage area;

the outlet pipe is communicated with the upper part of the separation cavity, is connected to the air return pipe and is used for discharging the gaseous refrigerant on the upper part of the separation cavity to the air return pipe;

the head end of the liquid return pipe is arranged in the liquid storage area, extends out of the barrel body and is connected to the outlet pipe, so that the mixed liquid of the refrigeration oil and the liquid refrigerant in the liquid storage area is discharged to the gas return pipe; and is

At least one part of the capillary tube is attached to the air return pipe or penetrates through the air return pipe, wherein the liquid return pipe is constructed to ensure that liquid refrigerant entering the air return pipe exchanges heat with refrigerant in the capillary tube to be completely gasified, and simultaneously, the content of gaseous refrigerant in the capillary tube is reduced.

2. The compression refrigeration system of claim 1, wherein

The liquid return pipe extends upwards from the head end of the liquid return pipe, and extends out of the upper part of the barrel body to be connected to the outlet pipe.

3. The compression refrigeration system of claim 1, wherein

The liquid return pipe extends downwards from the head end of the liquid return pipe, extends from the bottom of the barrel body and then is connected to the outlet pipe in an extending mode.

4. The compression refrigeration system of claim 1, wherein

The ratio of the inner sectional area of the liquid return pipe to the inner sectional area of the outlet pipe is 2-10%.

5. The compression refrigeration system of claim 4, wherein

The ratio of the inner sectional area of the liquid return pipe to the inner sectional area of the outlet pipe is 3% -10%.

6. The compression refrigeration system of claim 5, wherein

The ratio of the inner sectional area of the liquid return pipe to the inner sectional area of the outlet pipe is 4-10%.

7. The compression refrigeration system of claim 1, wherein the gas-liquid separator further comprises:

and the inlet pipe is connected with the outlet of the evaporator and extends into the upper part of the separation cavity from the cylinder.

8. The compression refrigeration system of claim 7, wherein

The inlet pipe is arranged obliquely in the separation chamber, and the oblique direction faces away from the outlet pipe.

9. The compression refrigeration system of claim 1, wherein

And a drying filter is also arranged between the condenser and the capillary tube.

10. A refrigeration chiller comprising:

the compression refrigeration system according to any one of claims 1 to 9, the evaporator of the compression refrigeration system being used to provide refrigeration to the refrigerated freezing apparatus.