CN111435043A

CN111435043A - Compression type refrigerating system and refrigerating and freezing device

Info

Publication number: CN111435043A
Application number: CN201910028672.6A
Authority: CN
Inventors: 赵向辉; 梁静娜; 田红荀; 房雯雯; 张冰
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
Also published as: WO2020143787A1

Abstract

The invention provides a compression type refrigerating system and a refrigerating and freezing device, wherein the compression type refrigerating system comprises a compressor, a condenser, a capillary tube and an evaporator which are sequentially connected, and further comprises: the gas-liquid separator is arranged at the downstream of the refrigerant flow direction of the evaporator and is used for separating the refrigerant discharged by the evaporator according to phases; the evaporator discharge pipe is used for connecting an evaporator outlet with an inlet of the gas-liquid separator; the air return pipe is connected with the outlet of the gas-liquid separator and the inlet of the compressor; wherein the capillary comprises: the first capillary tube section is attached to the air return pipe or penetrates through the air return pipe so as to utilize the refrigerant in the air return pipe to primarily exchange heat of the refrigerant flowing through the capillary tube; the second capillary section is attached to or arranged in the evaporator discharge pipe in a penetrating way so as to utilize the refrigerant in the evaporator discharge pipe to ensure that the refrigerant flowing through the capillary tube exchanges heat secondarily. The scheme of the invention reduces the eruption noise at the outlet of the capillary tube and improves the heat exchange efficiency.

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 part in a refrigeration system, and the basic function of the refrigeration system is to separate and store refrigerant liquid in a return air pipe so as to prevent liquid impact of a compressor. The gas-liquid separator can temporarily store the redundant refrigerant liquid and also prevent the redundant refrigerant from flowing to a crankcase of the compressor to cause dilution of oil.

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 series, and further comprising: the gas-liquid separator is arranged at the downstream of the refrigerant flow direction of the evaporator and is used for separating the refrigerant discharged by the evaporator according to phases; the evaporator discharge pipe is used for connecting an evaporator outlet with an inlet of the gas-liquid separator; the air return pipe is connected with the outlet of the gas-liquid separator and the inlet of the compressor; wherein the capillary comprises: the first capillary tube section is attached to the air return pipe or penetrates through the air return pipe so as to utilize the refrigerant in the air return pipe to primarily exchange heat of the refrigerant flowing through the capillary tube; and the second capillary section is attached to the evaporator discharge pipe or penetrates through the evaporator discharge pipe so as to utilize the refrigerant in the evaporator discharge pipe to perform secondary heat exchange on the refrigerant flowing through the capillary.

Optionally, the gas-liquid separator comprises: and the cylinder body limits a separation cavity, the separation cavity is used for enabling the liquid refrigerant discharged by the evaporator to settle at the lower part of the separation cavity, and the evaporator discharge pipe discharges the refrigerant from the upper part of the cylinder body to the gas-liquid separator towards the upper part of the separation cavity.

Optionally, the gas-liquid separator further comprises: the inlet pipe is connected with the evaporator discharge pipe and extends into the separation cavity from the upper part of the cylinder; and an outlet pipe extending from the upper part of the separation chamber to the bottom of the cylinder and further connected to the air return pipe.

Optionally, the outlet tube comprises: the first outlet pipe section is arranged in the separation cavity, the head end opening of the first outlet pipe section is positioned at the upper part of the separation cavity so as to discharge gaseous refrigerants at the upper part of the separation cavity, and the first outlet pipe section obliquely extends to the bottom of the separation cavity; and the second outlet pipe section is connected with the tail end of the first outlet pipe section and extends upwards to the air return pipe outside the cylinder body.

Optionally, the first outlet section is inclined in a direction offset from the direction of extension of the inlet tube.

Optionally, the outlet tube further comprises: and a balance pipe section connected to the second outlet pipe section and the upper part of the separation chamber to balance the pressure in the outlet pipe.

Optionally, the first outlet pipe section is provided with an oil return hole on the lower portion of the separation chamber, so that the mixed liquid of the refrigeration oil and the liquid refrigerant deposited at the bottom of the separation chamber enters the outlet pipe.

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.

According to the compression type refrigeration system, the capillary tube is divided into two tube sections, and the two tube sections respectively exchange heat with the evaporator discharge pipe and the air return pipe, so that the content of gaseous refrigerants at the outlet of the capillary tube is reduced, the eruption noise at the position is reduced, and the sound quality at the position is improved.

Furthermore, in the compression refrigeration system, part of liquid refrigerant in the discharge pipe of the evaporator is evaporated in the heat exchange process with 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 overall 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 diagram 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;

figure 3 is a basic principle schematic of a pressure-enthalpy diagram;

FIG. 4 is a schematic illustration of a comparative arrangement of a compression refrigeration system according to one embodiment of the present invention;

FIG. 5 is a pressure-enthalpy diagram for a compression refrigeration system of a comparative scheme;

FIG. 6 is a pressure enthalpy diagram of a compression type refrigeration system according to an embodiment of the present invention; and

fig. 7 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. 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 in a refrigerant flow direction, and separates 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 evaporator discharge pipe 180 is used to connect the outlet of the evaporator 140 with the inlet of the gas-liquid separator 150. The gas return pipe 170 connects the outlet of the gas-liquid separator 150 with the inlet of the compressor 110.

The capillary 130 may include: a first capillary segment 131 and a second capillary segment 132. That is, the capillary tube 130 may be divided into a first capillary tube section 131 located upstream and a second capillary tube section 132 located downstream in the flow direction of the refrigerant. The first capillary tube section 131 is attached to the muffler 170, so that the refrigerant flowing through the capillary tube 130 exchanges heat for the first time by using the refrigerant in the muffler 170; the second capillary segment 132 is disposed adjacent to the evaporator discharge pipe 180 to exchange heat with the refrigerant flowing through the capillary 130 for a second time by using the refrigerant in the evaporator discharge pipe 180. So that the refrigerant in the capillary tube 130 gradually exchanges heat while flowing.

In another embodiment, the first capillary segment 131 may also be inserted into the return air pipe 170, and the second capillary segment may also be inserted into the evaporator discharge pipe 180.

Because the refrigerant flowing through the capillary tube 130 is subjected to multi-section heat exchange, the gaseous refrigerant is partially or completely liquefied, so that the gaseous components in the refrigerant at the outlet of the capillary tube 130 are reduced, the eruption noise at the place is reduced, and the sound quality at the place is improved.

Part of the liquid refrigerant in the evaporator discharge pipe 180 is evaporated in the heat exchange process with the capillary tube 130, so that the refrigerant at the outlet of the evaporator 140 is in a gas-liquid two-phase state, the heat exchange efficiency of the evaporator 140 is improved, and the overall power consumption can be reduced.

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.

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 gas-liquid separator 150 may include: a cylinder 151, an inlet pipe 152, an outlet pipe 153, 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 in the lower portion of the separation chamber 154. The evaporator discharge pipe 140 discharges the refrigerant from the upper portion of the cylindrical body 151 to the gas-liquid separator 150.

The inlet pipe 152 is connected to the evaporator discharge pipe 180 and extends from the upper portion of the drum 151 into the separation chamber 154. An outlet pipe 153 extends from the upper part of the separation chamber 154 to the bottom of the cylinder 151 and further to a return pipe 170 connected to the compressor 110.

A first outlet pipe section 156 of the outlet pipe 153, which is disposed inside the separation chamber 154, has a head end opening at an upper portion of the separation chamber 154 to allow the gaseous refrigerant at the upper portion of the separation chamber 154 to be discharged, and extends obliquely to a bottom of the separation chamber 154; and a second outlet pipe section 157 of the outlet pipe 153 connected to the end of the first outlet pipe section 156 and extending upward outside the cylinder 151 to the muffler 170.

In order to prevent the refrigerant of the inlet pipe 152 from directly entering the outlet pipe 153, the first outlet pipe section 156 may be inclined in a direction offset from the extending direction of the inlet pipe 152.

Outlet pipe 153 may also include a balance pipe section 155 connected to second outlet pipe section 157 and to an upper portion of separation chamber 154 for balancing the pressure within outlet pipe 153.

The first outlet pipe section 156 is opened with an oil return hole 158 at a lower section of the lower portion of the separation chamber 154 to allow the refrigerant oil deposited at the bottom of the separation chamber 154 to enter the outlet pipe 153, so that the refrigerant oil can be circulated back to the compressor 110.

The effect verification of the compression-type refrigeration system 100 of the embodiment and 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 3 is a schematic diagram of the basic principle of the pressure-enthalpy diagram. In the pressure-enthalpy diagram, the ordinate is the logarithm of the absolute pressure lgP (in Bar), 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. 4 is a schematic view of a comparative version of a compression refrigeration system 100 according to one embodiment of the present invention, the compression refrigeration system 400 in this comparative version differing from the compression refrigeration system 100 of this embodiment only in that only a portion of the capillary tube 430 is positioned against the return tube 470, without the presence of the second capillary segment 132 described above.

Fig. 5 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. 6 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 in the compressor 110 is in 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 in the condenser 120 flows from a state point 62 (inlet of the condenser 120) to a state point 63 (outlet of the condenser 120), and due to the heat release effect of the condenser 120, the high-temperature and high-pressure superheated gaseous refrigerant is changed into a high-pressure liquid refrigerant (with a smaller supercooling degree);

then enters the capillary 130 for throttling and pressure reduction (the pressure is reduced from the pressure of a state point 63 (an inlet of the capillary 130) to the pressure of a state point 64 (an outlet of the capillary 130)), and exchanges heat with the liquid refrigerant in the evaporator discharge pipe 180 and the gaseous 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, the refrigerant passing through the evaporator discharge pipe 180 exchanges heat with the refrigerant in the second capillary tube section 132 to become slightly superheated steam (state point 66) and then enters the gas-liquid separator 150, the refrigerant which enters the gas return pipe 170 after being output from the gas-liquid separator 150 is also slightly superheated steam, enters the gas return pipe 170 to exchange heat with the other part of the capillary tube 130 (state point 66 to state point 61), and then enters the compressor 110 to circulate and reciprocate.

As can be seen from a comparison between fig. 5 and 6, 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 outlet eruption noise of the capillary tube 130 is large and the sound quality is poor.

The embodiment also provides a refrigerating and freezing device. Fig. 7 is a schematic block diagram of a refrigeration and freezing apparatus 70 according to an embodiment of the present invention, the refrigeration 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, the evaporator 140 can 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. A compression refrigeration system comprises a compressor, a condenser, a capillary tube and an evaporator which are connected in sequence, and further comprises:

the gas-liquid separator is arranged at the downstream of the refrigerant flow direction of the evaporator and is used for separating the refrigerant discharged by the evaporator according to phases;

an evaporator discharge pipe for connecting the evaporator outlet with the inlet of the gas-liquid separator;

the air return pipe is connected with the outlet of the gas-liquid separator and the inlet of the compressor;

the capillary tube includes:

the first capillary tube section is attached to the air return pipe or penetrates through the air return pipe so as to utilize the refrigerant in the air return pipe to primarily exchange heat of the refrigerant flowing through the capillary tube;

and the second capillary tube section is attached to the evaporator discharge pipe or penetrates through the evaporator discharge pipe so as to utilize the refrigerant in the evaporator discharge pipe to carry out secondary heat exchange on the refrigerant flowing through the capillary tube.

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

a cylinder defining a separation chamber for settling a liquid refrigerant discharged from the evaporator at a lower portion of the separation chamber, and

and the evaporator discharge pipe discharges the refrigerant to the upper part of the separation cavity.

3. The compression refrigeration system of claim 2, wherein the gas-liquid separator further comprises:

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

an outlet pipe extending from an upper portion of the separation chamber to a bottom portion of the drum and further connected to a gas return pipe leading to the gas return pipe.

4. The compression refrigeration system of claim 3, wherein the outlet tube comprises:

the first outlet pipe section is arranged in the separation cavity, the head end opening of the first outlet pipe section is positioned at the upper part of the separation cavity so as to discharge gaseous refrigerant at the upper part of the separation cavity, and the first outlet pipe section obliquely extends to the bottom of the separation cavity; and

and the second outlet pipe section is connected with the tail end of the first outlet pipe section and extends upwards to the air return pipe outside the cylinder.

5. The compression refrigeration system of claim 4, wherein

The inclined direction of the first outlet pipe section and the extending direction of the inlet pipe are arranged in a staggered mode.

6. The compression refrigeration system of claim 4, wherein the outlet tube further comprises:

a balance pipe section connected to the second outlet pipe section and an upper portion of the separation chamber to balance a pressure in the outlet pipe.

7. The compression refrigeration system of claim 4, wherein

And the first outlet pipe section is provided with an oil return hole at the lower part of the separation cavity, so that the refrigeration oil deposited at the bottom of the separation cavity enters the outlet pipe.

8. The compression refrigeration system of claim 1, wherein

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

9. A refrigeration chiller comprising:

the compression refrigeration system according to any one of claims 1 to 8, the evaporator of the compression refrigeration system being used to provide refrigeration to the refrigerated freezing apparatus.