阅读说明：本技术 一种带中间冷媒过冷的co2双级压缩制冷系统 (CO with intermediate refrigerant supercooling2Two-stage compression refrigerating system ) 是由 苟顺国 何铭 于 2021-07-12 设计创作，主要内容包括：本发明公开了一种带中间冷媒过冷的CO-2双级压缩制冷系统,属于空气制冷技术领域。包括一级压缩系统、二级压缩系统和中间过冷系统,一级压缩系统包括与一级压缩机依次连接的一级压缩高压油分离器、一级压缩高压储油罐和一级压缩滤油器,二级压缩系统包括与二级压缩机依次连接的二级压缩高压油分离器、二级高压缩压储油罐和二级压缩滤油器,中间过冷系统包括与中间过冷压缩机依次连接的中间过冷冷凝器、储液器、过滤器、视液镜和中间过冷电子膨胀阀。本发明能够实现将CO-2冷媒经过一级压缩和二级压缩后经中间过冷系统进行过冷,一路通过闪蒸罐气化后进入二级压缩系统完成二级压缩,另一路通过蒸发器回到一级压缩系统完成制冷循环。(The invention discloses a CO with intermediate refrigerant supercooling 2 A double-stage compression refrigeration system belongs to the technical field of air refrigeration. Comprises a first-stage compression system, a second-stage compression system and an intermediate supercooling system, wherein the first-stage compression system comprises a first refrigerant compressor and a second refrigerant compressorThe secondary compression system comprises a secondary compression high-pressure oil separator, a secondary compression high-pressure oil storage tank and a secondary compression oil filter which are sequentially connected with the secondary compressor, and the intermediate supercooling system comprises an intermediate supercooling condenser, a liquid reservoir, a filter, a liquid viewing mirror and an intermediate supercooling electronic expansion valve which are sequentially connected with the intermediate supercooling compressor. The invention can realize the reaction of CO 2 The refrigerant is subcooled by an intermediate subcooling system after being subjected to primary compression and secondary compression, one path of refrigerant is gasified by a flash tank and then enters a secondary compression system to complete secondary compression, and the other path of refrigerant returns to the primary compression system through an evaporator to complete refrigeration cycle.)

1. CO with intermediate refrigerant supercooling₂The double-stage compression refrigeration system is characterized in that: the system comprises a primary compression system, a secondary compression system and an intermediate supercooling system;

the primary compression system is used for compressing CO₂The refrigerant is fully refrigerated, and the secondary compression system is used for compressing CO₂The refrigerant forms high exhaust pressure and exhaust temperature to fully release heat, and the intermediate supercooling system is used for converting CO into CO₂The refrigerant fully releases heat to make CO₂Condensing the refrigerant to below the critical temperature;

the primary compression system comprises a primary compressor (1), a compressor controller (21), a primary compression frequency converter (41), a primary compression high-pressure oil separator (39), a primary compression high-pressure oil storage tank (40) and a primary compression oil filter (42), wherein the primary compression frequency converter (41) and the compressor controller (21) are both connected with the primary compressor (1), one end of the primary compressor (1) is connected with the primary compression high-pressure oil separator (39), one end of the primary compression high-pressure oil separator (39) is connected with the primary compression high-pressure oil storage tank (40), and the primary compression high-pressure oil storage tank (40) is sequentially connected with the primary compression oil filter (42) and the primary compressor (1) to form a loop;

the two-stage compression system comprises a two-stage compressor (2), a compressor controller (21), a two-stage compression high-pressure oil separator (4), a two-stage compression high-pressure oil storage tank (5), a two-stage compression oil filter (7), a cooler (11), a gas cooling controller (25), a primary electronic expansion valve (37) and a supercooling heat exchanger (34), wherein the compressor controller (21) is connected with the two-stage compressor (2), the two-stage compressor (2) is connected with the two-stage compression high-pressure oil separator (4), one end of the two-stage compression high-pressure oil separator (4) is connected with the two-stage compression high-pressure oil storage tank (5), and the two-stage compression high-pressure oil storage tank (5) is sequentially connected with the two-stage compression oil filter (7) and the two-stage compressor (2) to form a loop;

the other end of the first-stage compression high-pressure oil separator (39) is connected with a second-stage compressor (2), the other end of the second-stage compression high-pressure oil separator (4) is connected with a cooler (11), and the cooler (11) is sequentially connected with a gas cooling controller (25), a primary electronic expansion valve (37) and a supercooling heat exchanger (34);

the intermediate supercooling system comprises a compressor frequency converter (31), a compressor controller (21), an intermediate supercooling compressor (3), an intermediate supercooling condenser (32), a liquid storage device (33), a filter (9), a liquid viewing mirror (36), an intermediate supercooling electronic expansion valve (38) and a gas-liquid separator (35), the compressor frequency converter (31) and the compressor controller (21) are both connected with the intermediate supercooling compressor (3), one end of the intermediate supercooling compressor (3) is sequentially connected with an intermediate supercooling condenser (32), a liquid storage device (33), a filter (9), a liquid viewing mirror (36) and an intermediate supercooling electronic expansion valve (38), the intermediate supercooling electronic expansion valve (38) is connected with the supercooling heat exchanger (34), the supercooling heat exchanger (34) is sequentially connected with a gas-liquid separator (35) and an intermediate supercooling compressor (3) to form a loop;

the supercooling heat exchanger (34) is also sequentially connected with a flash tank (12) and a flash gas bypass valve (23), and the flash gas bypass valve (23) is connected with the secondary compression system to form a loop; flash evaporation gas bypass valve (23) are connected with gas cooling controller (25), filter (9) are connected to the other end of flash tank (12), the export of filter (9) is divided into two the tunnel, gets into evaporimeter (17) through the electronic evaporation pressure regulating valve (18) that sets up all the way and connects second grade compression system and accomplish secondary compression, and another way gets into evaporimeter (17) through electronic evaporation pressure regulating valve (18) and connects one-level compression system and accomplish refrigeration cycle.

2. The CO with intercooling of claim 1₂The double-stage compression refrigeration system is characterized in that: the primary compression system further comprises a check valve (6) and a primary compression filter (44) which are connected with the primary compressor (1), the primary compression high-pressure oil storage tank (40) is further connected with a primary compression oil pressure difference valve (45), and a primary compression high-pressure oil regulating valve (43) is further arranged between the primary compression oil filter (42) and the primary compressor (1).

3. The CO with intercooling of claim 1₂The double-stage compression refrigeration system is characterized in that: the two-stage compression system further comprises a check valve (6) and a two-stage compression air inlet filter (46) which are connected with the two-stage compressor (2), the two-stage compression high-pressure oil storage tank (5) is further connected with a two-stage compression oil pressure difference valve (10), and a two-stage compression high-pressure oil regulating valve (8) is further arranged between the two-stage compression oil filter (7) and the two-stage compressor (2).

4. The CO with intercooling of claim 1₂The double-stage compression refrigeration system is characterized in that: the gas cooling controller (25) is further connected with a high-pressure sensor (24), the high-pressure sensor (24) is connected with the cooler (11), and the high-pressure sensor (24) is further connected with a high-pressure filter (22).

5. The CO with intercooling of claim 1₂The double-stage compression refrigeration system is characterized in that: the intermediate supercooling system further comprisesComprising a check valve (6) arranged between the intermediate subcooling compressor (3) and the intermediate subcooling condenser (32).

6. The CO with intercooling of claim 1₂The double-stage compression refrigeration system is characterized in that: flash tank (12) one end is connected with ball valve (13), and the other end is connected with level sensor (26), level sensor (26) are connected with liquid level monitor (27).

7. The CO with intercooling of claim 1₂The double-stage compression refrigeration system is characterized in that: the outlet of the filter (9) is divided into two paths, which are specifically as follows: two ways all include ball valve (13), drier-filter (14), solenoid valve (15), secondary electronic expansion valve (16), evaporimeter (17) and electron evaporation pressure regulating valve (18) be connected with filter (9) in proper order, ball valve (13), drier-filter (14), solenoid valve (15), secondary electronic expansion valve (16) and evaporimeter (17) all are connected with overheat controller (28), electron evaporation pressure regulating valve (18) are connected with pressure regulating valve controller (29).

8. The CO with intercooling of claim 1₂The double-stage compression refrigeration system is characterized in that: and the air inlet pipelines of the first-stage compression system, the second-stage compression system and the intermediate supercooling system are respectively provided with a low-pressure safety protection device (20), and the air outlet pipelines of the first-stage compression system, the second-stage compression system and the intermediate supercooling system are respectively provided with a high-pressure safety protection device (19).

9. The CO with intercooling of claim 1₂The double-stage compression refrigeration system is characterized in that: the system also comprises a leakage monitoring device (30), wherein the leakage monitoring device (30) is connected with the primary compression system, the secondary compression system and the intermediate supercooling system.

Technical Field

The invention belongs to the technical field of air refrigeration, and particularly relates to CO with intermediate refrigerant supercooling₂A two-stage compression refrigeration system.

Background

With the rapid development of national economy and the improvement of the living standard of people in China, the application of the heat pump products such as refrigeration, air conditioning and heat pump products in the fields of industry, commerce, civilian use and the like is increasing. China is a large manufacturing country and a large using country of the refrigeration and air-conditioning industry, and both the installed capacity of equipment and the manufactured or used variety are in the forefront of the world. The refrigeration and air conditioning technology improves the quality of life of people, but the consumed electric energy is more and more, and the environmental problems caused by the leakage of various refrigerants are more and more serious. Popularization and application of CO₂The refrigerant has important significance for saving energy, reducing emission, promoting social sustainable development and building a low-carbon society.

Condensation temperature and CO of existing traditional refrigerant (R22, etc.) refrigeration system₂The cooling temperature of the refrigerant, whether water cooling or air cooling, depends on the ambient temperature at that time, the ambient temperature is high-efficiency and low, the refrigerating capacity is small, the ambient temperature is low-efficiency and high-refrigerating capacity is large, and the system is greatly influenced by the environment. CO 2₂The refrigerant system is greatly influenced by the ambient temperature, and the ambient temperature exceeds CO₂After the critical temperature of (C), CO₂The efficiency of the refrigerating system is greatly reduced, the intermediate refrigerant cooling system can control the refrigerant to obtain lower condensing temperature and supercooling before evaporation and interception, and can be completely controlled below critical temperature, and the purpose of supercooling is to reduce flash gas generated in the throttling process so as to improve the unit refrigerating capacity.

Disclosure of Invention

The invention aims to provide CO with intermediate refrigerant supercooling₂A two-stage compression refrigeration system.

In order to achieve the purpose, the technical scheme of the invention is as follows: beltIntercooled CO₂The double-stage compression refrigeration system comprises a first-stage compression system, a second-stage compression system and an intermediate supercooling system;

the primary compression system is used for compressing CO₂The refrigerant is fully refrigerated, and the secondary compression system is used for compressing CO₂The refrigerant forms high exhaust pressure and exhaust temperature to fully release heat, and the intermediate supercooling system is used for converting CO into CO₂The refrigerant fully releases heat to make CO₂Condensing the refrigerant to below the critical temperature;

the primary compression system comprises a primary compressor, a compressor controller, a primary compression frequency converter, a primary compression high-pressure oil separator, a primary compression high-pressure oil storage tank and a primary compression oil filter, wherein the primary compression frequency converter and the compressor controller are both connected with the primary compressor;

the secondary compression system comprises a secondary compressor, a compressor controller, a secondary compression high-pressure oil separator, a secondary compression high-pressure oil storage tank, a secondary compression oil filter, a cooler, a gas cooling controller, a primary electronic expansion valve and a supercooling heat exchanger, wherein the compressor controller is connected with the secondary compressor, the secondary compressor is connected with the secondary compression high-pressure oil separator, one end of the secondary compression high-pressure oil separator is connected with the secondary compression high-pressure oil storage tank, and the secondary compression oil storage tank is sequentially connected with the secondary compression oil filter and the secondary compressor to form a loop;

the other end of the first-stage compression high-pressure oil separator is connected with a second-stage compressor, the other end of the second-stage compression high-pressure oil separator is connected with a cooler, and the cooler is sequentially connected with a gas cooling controller, a primary electronic expansion valve and a supercooling heat exchanger;

the intermediate supercooling system comprises a compressor frequency converter, a compressor controller, an intermediate supercooling compressor, an intermediate supercooling condenser, a liquid storage device, a filter, a liquid viewing mirror, an intermediate supercooling electronic expansion valve and a gas-liquid separator, wherein the compressor frequency converter and the compressor controller are both connected with the intermediate supercooling compressor;

the supercooling heat exchanger is also sequentially connected with a flash tank and a flash gas bypass valve, and the flash gas bypass valve is connected with the secondary compression system to form a loop; the flash gas bypass valve is connected with the gas cooling controller, the other end of the flash tank is connected with the filter, the outlet of the filter is divided into two paths, one path of the filter enters the evaporator through the secondary electronic expansion valve, the evaporator is connected with the second-stage compression system to complete secondary compression, and the other path of the filter enters the evaporator through the secondary electronic expansion valve and is connected with the first-stage compression system to complete refrigeration cycle.

Furthermore, the first-stage compression system further comprises a check valve and a first-stage compression filter which are connected with the first-stage compressor, the first-stage compression high-pressure oil storage tank is further connected with a first-stage compression oil pressure difference valve, and a first-stage compression high-pressure oil regulating valve is further arranged between the first-stage compression oil filter and the first-stage compressor.

Furthermore, the second-stage compression system also comprises a check valve and a second-stage compression air inlet filter which are connected with the second-stage compressor, the second-stage compression high-pressure oil storage tank is also connected with a second-stage compression oil pressure difference valve, and a second-stage compression high-pressure oil regulating valve is also arranged between the second-stage compression oil filter and the second-stage compressor.

Further, the gas cooling controller is further connected with a high-pressure sensor, the high-pressure sensor is connected with the cooler, and the high-pressure sensor is further connected with a high-pressure filter.

Further, the intermediate subcooling system further comprises a check valve disposed between the intermediate subcooling compressor and the intermediate subcooling condenser.

Further, flash tank one end is connected with the ball valve, and the other end is connected with level sensor, level sensor is connected with the liquid level monitor.

Further, the outlet of the filter is divided into two paths, which specifically include: the two paths of the pipeline system comprise a ball valve, a drying filter, an electromagnetic valve, a secondary electronic expansion valve, an evaporator and an electronic evaporation pressure regulating valve which are sequentially connected with a filter, the ball valve, the drying filter, the electromagnetic valve, the secondary electronic expansion valve and the evaporator are all connected with an overheating controller, and the electronic evaporation pressure regulating valve is connected with a pressure regulating valve controller.

Furthermore, the air inlet pipelines of the first-stage compression system, the second-stage compression system and the intermediate supercooling system are respectively provided with a low-pressure safety protection device, and the air outlet pipelines of the first-stage compression system, the second-stage compression system and the intermediate supercooling system are respectively provided with a high-pressure safety protection device.

And the system further comprises a leakage monitoring device, and the leakage monitoring device is connected with the primary compression system, the secondary compression system and the intermediate supercooling system.

Due to the adoption of the technical scheme, the invention has the beneficial effects that: the invention can convert CO into CO by arranging the first-stage compression system, the second-stage compression system and the intermediate supercooling system₂The refrigerant is compressed into pressure and temperature suitable for the suction end of a secondary compression system by a primary compression system, is separated by a primary compression high-pressure oil separator and then is compressed into high-temperature and high-pressure gas by a secondary compressor, is subcooled by a condenser, is subcooled by an intermediate subcooling system, and finally returns to the primary compression system by an evaporator in two ways to complete refrigeration circulation and the secondary compression by the secondary compression system.

Drawings

FIG. 1 is a block diagram of the present invention;

the labels in the figure are: 1-a first-stage compressor; 2-a two-stage compressor; 3-an intermediate subcooling compressor; 4-a two-stage compression high-pressure oil separator; 5-two-stage compression high-pressure oil storage tank; 6-check valve; 7-a two-stage compression oil filter; 8-a two-stage compression oil regulating valve; 9-a filter; 10-a two-stage compression oil differential valve; 11-a cooler; 12-a flash tank; 13-a ball valve; 14-drying the filter; 15-an electromagnetic valve; 16-a secondary electronic expansion valve; 17-an evaporator; 18-electronic vapour pressure regulating valve; 19-high pressure safety devices; 20-low pressure safety devices; 21. a compressor controller; 22-a high pressure filter; 23-flash gas bypass valve; 24-a high pressure sensor; 25-gas cooling controller; 26-a liquid level sensor; 27-a liquid level monitor; 28-superheat controller; 29-pressure regulating valve control; 30-leakage monitoring; 31-compressor inverter; 32-an intermediate subcooling condenser; 33-a reservoir; 34-a subcooling heat exchanger; 35-a gas-liquid separator; 36-liquid sight glass; 37-primary electronic expansion valve; 38-intermediate subcooling electronic expansion valve; 39-first stage compression high pressure oil separator; 40-first-stage compression high-pressure oil storage tank; 41-first-stage compression frequency converter; 42-first stage compression oil filter; 43-first-stage compression high-pressure oil regulating valve; 44-first stage compression filter; 45-first-stage compression oil differential valve; 46-two stage compression intake filter.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the present embodiment provides a CO with intercooling of the intermediate refrigerant₂The double-stage compression refrigeration system comprises a first-stage compression system, a second-stage compression system and an intermediate supercooling system;

the first stage compression system of the present embodiment is used to compress CO₂The refrigerant is fully refrigerated, and the secondary compression system is used for compressing CO₂The refrigerant forms high exhaust pressure and exhaust temperature to fully release heat, and the intermediate supercooling system is used for removing CO₂The refrigerant fully releases heat to make CO₂Condensing the refrigerant to below the critical temperature;

the first-stage compression system of the embodiment comprises a first-stage compressor 1, a compressor controller 21, a first-stage compression frequency converter 41, a first-stage compression high-pressure oil separator 39, a first-stage compression high-pressure oil storage tank 40 and a first-stage compression oil filter 42, wherein the first-stage compression frequency converter 41 and the compressor controller 21 are both connected with the first-stage compressor 1, one end of the first-stage compressor 1 is connected with the first-stage compression high-pressure oil separator 39, one end of the first-stage compression high-pressure oil separator 39 is connected with the first-stage compression high-pressure oil storage tank 40, and the first-stage compression high-pressure oil storage tank 40 is sequentially connected with the;

the two-stage compression system of the embodiment comprises a two-stage compressor 2, a compressor controller 21, a two-stage compression high-pressure oil separator 4, a two-stage compression high-pressure oil storage tank 5, a two-stage compression oil filter 7, a cooler 11, a gas cooling controller 25, a primary electronic expansion valve 37 and a supercooling heat exchanger 34, wherein the compressor controller 21 is connected with the two-stage compressor 2, the two-stage compressor 2 is connected with the two-stage compression high-pressure oil separator 4, one end of the two-stage compression high-pressure oil separator 4 is connected with the two-stage compression high-pressure oil storage tank 5, and the two-stage compression high-pressure oil storage tank 5 is sequentially connected with the two;

further, the other end of the first-stage compression high-pressure oil separator 39 is connected with the second-stage compressor 2, the other end of the second-stage compression high-pressure oil separator 4 is connected with the cooler 11, and the cooler 11 is sequentially connected with the gas cooling controller 25, the primary electronic expansion valve 37 and the supercooling heat exchanger 34;

the intermediate supercooling system of the embodiment comprises a compressor frequency converter 31, a compressor controller 21, an intermediate supercooling compressor 3, an intermediate supercooling condenser 32, a liquid reservoir 33, a filter 9, a liquid viewing mirror 36, an intermediate supercooling electronic expansion valve 38 and a gas-liquid separator 35, wherein the compressor frequency converter 31 and the compressor controller 21 are both connected with the intermediate supercooling compressor 3, one end of the intermediate supercooling compressor 3 is sequentially connected with the intermediate supercooling condenser 32, the liquid reservoir 33, the filter 9, the liquid viewing mirror 36 and the intermediate supercooling electronic expansion valve 38, the intermediate supercooling electronic expansion valve 38 is connected with a supercooling heat exchanger 34, and the supercooling heat exchanger 34 is sequentially connected with the gas-liquid separator 35 and the intermediate supercooling compressor 3 to form a loop;

further, the supercooling heat exchanger 34 of the present embodiment is further sequentially connected with a flash tank 12 and a flash gas bypass valve 23, and the flash gas bypass valve 23 is connected with the secondary compression system to form a loop; flash gas bypass valve 23 is connected with gas cooling controller 25, and the other end of flash tank 12 is connected filter 9, and the export of filter 9 divide into two the tunnel, and one the tunnel enters into evaporimeter 17 through the secondary electronic expansion valve 18 that sets up and connects second grade compression system and accomplish the secondary compression, and another tunnel enters into evaporimeter 17 through secondary electronic expansion valve 18 and connects one-level compression system and accomplish refrigeration cycle, the export of filter 9 divide into two the tunnel, and it is specific: the two paths of the refrigerant pipeline all comprise a ball valve 13, a drying filter 14, an electromagnetic valve 15, a secondary electronic expansion valve 16, an evaporator 17 and an electronic evaporation pressure regulating valve 18 which are sequentially connected with the filter 9, the ball valve 13, the drying filter 14, the electromagnetic valve 15, the secondary electronic expansion valve 16 and the evaporator 17 are all connected with an overheating controller 28, and the electronic evaporation pressure regulating valve 18 is connected with a pressure regulating valve controller 29.

Further, the first-stage compression system further comprises a check valve 6 and a first-stage compression filter 44 which are connected with the first-stage compressor 1, the first-stage compression high-pressure oil storage tank 40 is further connected with a first-stage compression oil pressure difference valve 45, and a first-stage compression high-pressure oil regulating valve 43 is further arranged between the first-stage compression oil filter 42 and the first-stage compressor 1.

Further, the two-stage compression system of the embodiment further includes a check valve 6 and a two-stage compression air intake filter 46 which are connected with the two-stage compressor 2, the two-stage compression high-pressure oil storage tank 5 is further connected with a two-stage compression oil pressure difference valve 10, and a two-stage compression high-pressure oil regulating valve 8 is further arranged between the two-stage compression oil filter 7 and the two-stage compressor 2.

Further, the gas cooling controller 25 is connected to a high pressure sensor 24, the high pressure sensor 24 is connected to the cooler 11, and the high pressure sensor 24 is connected to the high pressure filter 22.

Further, the intermediate subcooling system further includes a check valve 6 disposed between the intermediate subcooling compressor 3 and the intermediate subcooling condenser 32.

Further, one end of the flash tank 12 is connected with the ball valve 13, the other end is connected with a liquid level sensor 26, and the liquid level sensor 26 is connected with a liquid level monitor 27.

Further, the air inlet pipelines of the first-stage compression system, the second-stage compression system and the intermediate supercooling system are respectively provided with a low-pressure safety protection device 20, and the air outlet pipelines of the first-stage compression system, the second-stage compression system and the intermediate supercooling system are respectively provided with a high-pressure safety protection device 19.

Further, the system also comprises a leakage monitoring device 30, and the leakage monitoring device 30 is connected with the primary compression system, the secondary compression system and the intermediate supercooling system.

When the invention works specifically, the working process is as follows: CO 2₂The refrigerant passes through a first-stage compression system, and the CO is compressed by a first-stage compressor controlled by a first-stage compression frequency converter₂Refrigerant is compressed into pressure and temperature suitable for the suction end of a secondary compressor, the compressor lubricating oil carried out by refrigerant in a pipeline is separated by a primary compression high-temperature oil separator and flows into a primary compression high-pressure liquid storage tank, the oil pressure difference of the compressor is controlled by a primary compression oil pressure difference valve, when the excessive oil pressure difference of the compressor is detected, the lubricating oil is supplemented to the primary compressor by the adjustment of a primary high-pressure oil adjusting valve after being filtered by a primary compression oil filter, then the gaseous refrigerant suitable for the secondary compression temperature and pressure is separated by the primary compression high-pressure oil separator and filtered by a secondary compression air inlet filter and is sucked into the secondary compressor to complete primary compression.

After the secondary compression sucks the gaseous refrigerant, the gaseous refrigerant is compressed into high-temperature and high-pressure gas by a compressor, the lubricant oil carried out by the refrigerant in the pipeline is separated by a secondary compression high-temperature oil separator and flows into a secondary compression high-pressure oil storage tank, the pressure difference of the compressor oil is controlled by a secondary compression oil difference valve, and when the pressure difference of the compressor oil is detected to be overlarge, the lubricant oil is regulated by a secondary high-pressure oil regulating valve and is supplied back to the secondary compressor. High-temperature high-pressure gas is separated by the secondary compression high-pressure oil separator, enters the cooler for cooling, takes away a large amount of heat through cooling, is cooled into a gas-liquid mixed refrigerant, and enters the supercooling heat exchanger for supercooling through throttling of the primary electronic throttle valve.

Supercooling process: the intermediate supercooling compressor is controlled by an intermediate supercooling frequency converter in an intermediate supercooling system to compress a refrigerant into high-temperature and high-pressure gas, the gas-liquid mixture condensed into intermediate temperature and intermediate pressure by an intermediate supercooling condenser enters a liquid storage tank to store redundant liquid refrigerants, part of the refrigerants are filtered by a filter and enter a supercooling heat exchanger through an intermediate supercooling electronic expansion valve, the refrigerants are evaporated into low-temperature and low-pressure refrigerants, so that the purpose of supercooling the main path refrigerants is achieved, the low-temperature and low-pressure refrigerants are separated by a gas-liquid separation tank, the low-temperature gas returns to a suction inlet of the intermediate supercooling compressor to complete supercooling circulation, the supercooled refrigerants enter a flash tank to flash and gasify part of the liquid refrigerants, the gasified flash gas is recycled to a secondary compressor through a flash gas bypass valve, and the low-temperature liquid refrigerants are filtered by the filter and divided into two paths: one path of refrigerant enters the evaporator through the secondary electronic expansion valve, the evaporator absorbs a large amount of heat to evaporate low-temperature liquid into low-temperature low-pressure gas, the low-temperature low-pressure gas returns to the secondary compressor through the secondary compression air inlet filter to complete secondary compression, the other path of refrigerant enters the evaporator through the secondary electronic expansion valve to evaporate a large amount of heat to evaporate low-temperature low-pressure liquid refrigerant into low-temperature low-pressure gas refrigerant, the pressure of the refrigerant is controlled by the pressure regulating valve, the pressure of the refrigerant is filtered by the primary compression filter to return to the primary compressor to complete refrigeration cycle.