Refrigeration system for cold store with differential pressure pre-cooling

Abstract

The application provides a cold storage refrigeration system with differential pressure precooling, comprising a cold storage, an outdoor unit module, a differential pressure precooling module and a refrigeration module; the outdoor unit module comprises a compressor, a gas-liquid separator, a condenser, a condensing fan, a liquid storage tank, an expansion valve, a bypass switching valve and an expansion valve switching valve; the differential pressure precooling module comprises a precooling heat exchanger, a precooling fan, a precooling switching valve and a pressure regulator; the refrigeration module comprises a refrigeration switching valve, a refrigeration heat exchanger, a refrigeration fan, a defrosting expansion valve, a defrosting switching valve, a defrosting bypass valve and a refrigeration outlet switching valve; the outlet of the refrigeration heat exchanger is divided into three paths, the first path is directly output, the second path is connected to the inlet of the precooling heat exchanger through the defrosting switching valve and the defrosting expansion valve, and the third path is connected to the inlet of the precooling heat exchanger through the defrosting bypass valve. The system integrates the precooling and refrigeration systems, improves the integration and operation efficiency of the cold storage system and saves cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food cold chain transportation, in particular to a cold storage refrigeration system with differential pressure precooling. BACKGROUND

[0002] The temperature of fruits and vegetables during harvesting is generally between 20-35℃, and such a high temperature will cause the vigorous metabolism of fruits and vegetables, so it is necessary to quickly reduce the temperature of fruits and vegetables, i.e. precooling, to maximize the quality and freshness of fruits and vegetables. The conventional cold storage refrigeration system usually only has cold storage function, and it is difficult to achieve rapid precooling when using the cold storage to precool fruits and vegetables.

[0003] The defect of cold storage precooling is that it takes a long time, generally 1-5 days are needed to reduce the temperature of fruits and vegetables to the cold storage temperature, and because the cold air under the refrigeration mode cannot penetrate the material, it can only contact the surface of the material or the package, and the material is not uniformly cooled.

[0004] Therefore, adding a differential pressure precooling function to the existing cold storage system can effectively solve the above problems.

[0005] Differential pressure precooling is to add a region in the cold storage, form an air duct in the region, and stack fruits and vegetables in the air duct, block the two sides and the top of the fruits and vegetables, so that the ventilation can only pass through the stack of fruits and vegetables, i.e. through the gap between the fruits and vegetables. Under the action of the negative pressure of the air duct, the cold air flow pre-cools the fruits and vegetables through the gap between the fruits and vegetables, realizes rapid cooling, and the efficiency is usually 2-6 times that of the cold storage refrigeration cooling.

[0006] However, adding a separate module with differential pressure precooling function to the cold storage system requires the addition of an extra precooling unit, and the management and operation costs of the cold storage will also be greatly increased.

[0007] How to integrate the original refrigeration system to realize unified precooling and refrigeration system combined operation has become a new problem that needs to be solved.

[0008] In order to solve the above problems, people have been seeking an ideal technical solution. SUMMARY

[0009] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a cold storage refrigeration system with differential pressure precooling, which has high integration degree, strong composite, switchable precooling and refrigeration, and combined operation.

[0010] In order to achieve the above purpose, the technical scheme adopted by the present application is: a cold storage refrigeration system with differential pressure precooling, comprising a cold storage, an outdoor unit module, a differential pressure precooling module and a refrigeration module, the differential pressure precooling module is arranged in a region of the cold storage;

[0011] The outdoor unit module comprises a compressor, a gas-liquid separator, a condenser, a condenser fan, a liquid storage tank, an expansion valve, a bypass switching valve and an expansion valve switching valve, an inlet end of the compressor is connected with the gas-liquid separator, an outlet end of the compressor is connected with the condenser, an inlet of the gas-liquid separator is used as a cold storage output pipeline; the condenser fan is used for heat dissipation of the condenser, an outlet of the condenser is connected with the liquid storage tank, a first outlet of the liquid storage tank is connected with the expansion valve and the expansion valve switching valve, a second outlet of the liquid storage tank is connected with the bypass switching valve, an outlet of the expansion valve switching valve and an outlet of the bypass switching valve are combined to be a cold storage input pipeline;

[0012] The differential pressure pre-cooling module comprises a pre-cooling heat exchanger, a pre-cooling fan, a pre-cooling switching valve and a pressure regulator, a first branch of the cold storage input pipeline is connected with an inlet of the pre-cooling heat exchanger through the pre-cooling switching valve, the pre-cooling fan is used for cold output of the pre-cooling heat exchanger, an outlet of the pre-cooling heat exchanger is connected with the pressure regulator, an outlet of the pressure regulator is connected with the cold storage output pipeline;

[0013] The refrigeration module comprises a refrigeration switching valve, a refrigeration heat exchanger, a refrigeration fan, a defrosting expansion valve, a defrosting switching valve, a defrosting bypass valve and a refrigeration outlet switching valve, a second branch of the cold storage input pipeline is connected with an inlet of the refrigeration heat exchanger through the refrigeration switching valve, the refrigeration fan is used for cold output of the refrigeration heat exchanger;

[0014] An outlet of the refrigeration heat exchanger is divided into three branches, a first branch is connected to the cold storage output pipeline through the refrigeration outlet switching valve, a second branch is connected to an inlet of the pre-cooling heat exchanger through the defrosting switching valve and the defrosting expansion valve, and a third branch is connected to the inlet of the pre-cooling heat exchanger through the defrosting bypass valve.

[0015] According to the above, when the refrigeration module and the differential pressure pre-cooling module are jointly associated to operate, the compressor, the condenser fan, the pre-cooling fan and the refrigeration fan work, the expansion valve switching valve, the refrigeration switching valve, the defrosting bypass valve and the pressure regulator are opened, and other valves are closed.

[0016] According to the above, when the refrigeration module defrosts, the compressor and the pre-cooling fan work, the bypass switching valve, the refrigeration switching valve, the defrosting switching valve and the pressure regulator are opened, and other valves are closed.

[0017] According to the above, when the differential pressure pre-cooling module independently operates, the compressor, the condenser fan and the pre-cooling fan work, the expansion valve switching valve, the pre-cooling switching valve and the pressure regulator are opened, and other valves and the refrigeration fan are closed.

[0018] According to the above, when the refrigeration module independently operates, the compressor, the condenser fan and the refrigeration fan work, the expansion valve switching valve, the refrigeration switching valve and the refrigeration outlet switching valve are opened, and other valves and the pre-cooling fan are closed.

[0019] The present application has outstanding substantial features and significant progress compared with the prior art, and has the following advantages.

[0020] 1. The pre-cooling system and the refrigeration system are integrated, and the pre-cooling system occupies one area of the cold storage, so that the fruits and vegetables are pre-cooled before being stored in the cold storage, and the storage efficiency is improved.

[0021] 2. The pre-cooling system and the refrigeration system share one outdoor module, and through pipeline optimization, the pre-cooling system can be independently operated, the refrigeration system can be independently operated, the pre-cooling system and the refrigeration system can be jointly operated, and the pre-cooling system can be operated under the defrosting state of the refrigeration system, so that the flexibility and integration of the system are greatly improved, the management is facilitated, and the operation cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the principle diagram of the cold storage refrigeration system with differential pressure pre-cooling in the present application.

[0023] Figure 2 is the assembly diagram of the cold storage refrigeration system with differential pressure pre-cooling in the present application.

[0024] Figure 3 is the operation principle diagram of the refrigeration module working alone in the present application.

[0025] Figure 4 is the operation principle diagram of the differential pressure pre-cooling module working alone in the present application.

[0026] Figure 5 is the principle diagram of the combined operation of the refrigeration module and the differential pressure pre-cooling module in the present application.

[0027] Figure 6 is the operation principle diagram of the refrigeration module under the defrosting mode in the present application.

[0028] In the figure: 1. Outdoor module; 2. Differential pressure pre-cooling module; 3. Refrigeration module; 4. Cold storage;

[0029] 101. Compressor; 102. Gas-liquid separator; 103. Condenser; 104. Condensing fan; 105. Liquid storage tank; 106. Expansion valve; 107. By-pass switching valve; 108. Expansion valve switching valve;

[0030] 201. Pre-cooling heat exchanger; 202. Pre-cooling fan; 203. Pre-cooling switching valve; 204. Pressure regulator;

[0031] 301. Refrigeration switching valve; 302. Refrigeration heat exchanger; 303. Refrigeration fan; 304. Defrosting expansion valve; 305. Defrosting switching valve; 306. Defrosting by-pass valve; 307. Refrigeration outlet switching valve. DETAILED DESCRIPTION

[0032] The technical solutions of the present application are described in further detail below through specific embodiments.

[0033] As shown in Figure 1 and Figure 2 A cold storage refrigeration system with differential pressure pre-cooling includes a cold storage 4, an outdoor unit module 1, a differential pressure pre-cooling module 2, and a refrigeration module 3. The differential pressure pre-cooling module 2 is arranged in a region of the cold storage, usually designed near the entrance, with the purpose of pre-cooling the fruits and vegetables before entering the cold storage for refrigerated storage, quickly cooling them to the required temperature, and then sending them to the refrigerated storage area of the cold storage for long-term storage, solving the slow pre-cooling speed defect of conventional cold storage.

[0034] The outdoor unit module 1 includes a compressor 101, a gas-liquid separator 102, a condenser 103, a condenser fan 104, a liquid storage tank 105, an expansion valve 106, a bypass switching valve 107, and an expansion valve switching valve 108. The inlet end of the compressor 101 is connected to the gas-liquid separator 102, and the outlet end is connected to the condenser 103. The inlet of the gas-liquid separator 102 serves as the cold storage output pipeline.

[0035] The condenser fan 104 is used for heat dissipation of the condenser 103. The outlet of the condenser 103 is connected to the liquid storage tank 105. The first outlet of the liquid storage tank 105 is connected to the expansion valve 106 and the expansion valve switching valve 108, and the second outlet is connected to the bypass switching valve 107. The outlet of the expansion valve switching valve 108 and the outlet of the bypass switching valve 107 are combined to serve as the cold storage input pipeline.

[0036] The differential pressure pre-cooling module 2 includes a pre-cooling heat exchanger 201, a pre-cooling fan 202, a pre-cooling switching valve 203, and a pressure regulator 204. The first branch of the cold storage input pipeline is connected to the inlet of the pre-cooling heat exchanger 201 through the pre-cooling switching valve 203. The pre-cooling fan 202 is used for cold output of the pre-cooling heat exchanger 201. The outlet of the pre-cooling heat exchanger 201 is connected to the pressure regulator 204. The outlet of the pressure regulator 204 is connected to the cold storage output pipeline.

[0037] The refrigeration module 3 includes a refrigeration switching valve 301, a refrigeration heat exchanger 302, a refrigeration fan 303, a defrosting expansion valve 304, a defrosting switching valve 305, a defrosting bypass valve 306, and a refrigeration outlet switching valve 307. The second branch of the cold storage input pipeline is connected to the inlet of the refrigeration heat exchanger 302 through the refrigeration switching valve 301. The refrigeration fan 303 is used for cold output of the refrigeration heat exchanger 302.

[0038] The outlet of the refrigeration heat exchanger 302 is divided into three paths. The first path is connected to the cold storage output pipeline through the refrigeration outlet switching valve 307. The second path is connected to the inlet of the precooling heat exchanger 201 through the defrost switching valve 305 and the defrost expansion valve 304. The third path is connected to the inlet of the precooling heat exchanger 201 through the defrost bypass valve 306.

[0039] The system has four operating modes, which are controlled in the following order:

[0040] like Figure 3 As shown, when the refrigeration module 3 operates independently, the compressor 101, condenser fan 104, and refrigeration fan 303 are working, the expansion valve switching valve 108, refrigeration switching valve 301, and refrigeration outlet switching valve 307 are open, and other valves and the pre-cooling fan are closed.

[0041] Specifically, the low-temperature, low-pressure refrigerant discharged from the refrigeration module or precooling module passes through the gas-liquid separator 102. The compressor 101 compresses the refrigerant during normal operation, increasing its temperature and pressure. The refrigerant then enters the condenser 103, where the condenser fan 104 drives ambient air to carry away the heat from the refrigerant. The cooled refrigerant then enters the liquid storage tank 105. After further throttling and depressurization by the expansion valve 106, the refrigerant forms a low-temperature, low-pressure gas-liquid two-phase fluid. This fluid then passes through the refrigeration switching valve 301 and enters the refrigeration heat exchanger 302. The refrigeration fan 303 inputs the cold air into the cold storage, creating a low-temperature environment for storing fruits and vegetables. The low-temperature refrigerant gas discharged from the refrigeration heat exchanger 302 enters the gas-liquid separator 102 through the refrigeration outlet switching valve 307.

[0042] like Figure 4 As shown, when the differential pressure precooling module 2 operates independently, the compressor, condenser fan, and precooling fan are working, the expansion valve switching valve, precooling switching valve, and pressure regulator are open, and other valves and the refrigeration fan are closed.

[0043] Specifically, the low-temperature, low-pressure refrigerant discharged from the refrigeration module or precooling module passes through the gas-liquid separator 102. The compressor 101 compresses the refrigerant during normal operation, increasing its temperature and pressure. The refrigerant then enters the condenser 103, where the condenser fan 104 drives ambient air to carry away the heat from the refrigerant. The cooled refrigerant then enters the liquid storage tank 105. After further throttling and depressurization by the expansion valve 106, the refrigerant forms a low-temperature, low-pressure gas-liquid two-phase fluid. This fluid then passes through the precooling switching valve 203 and enters the precooling heat exchanger 201. Under the action of the precooling fan 202, pressurized low-temperature cold air is output, which precools the fruits and vegetables through the precooling duct. The low-temperature refrigerant gas discharged from the precooling heat exchanger 201 passes through the pressure regulator 204 for pressure adjustment before entering the gas-liquid separator 102.

[0044] like Figure 6As shown, when the refrigeration module is defrosting, the compressor 101 and the precooling fan 202 are working, the bypass switching valve 107, the refrigeration switching valve 301, the defrosting switching valve 305 and the pressure regulator 204 are open, and the other valves are closed.

[0045] Specifically, when compressor 101 is working normally, the refrigerant temperature and pressure are increased, the condenser fan is not working, and the refrigerant directly enters the liquid receiver 105. It then passes through the second branch of the liquid receiver 105 and is output to the refrigeration module via the bypass switching valve 107 to provide heat for defrosting of the refrigeration module. The refrigerant with increased temperature continues to pass through the refrigeration switching valve 301 to enter the refrigeration heat exchanger 302 for heat exchange and defrosting. The frost layer on the surface of the heat exchanger melts under the heating of the high-temperature refrigerant. The cooled refrigerant passes through the defrosting switching valve 305 to enter the defrosting expansion valve 304 for throttling and pressure reduction to form a low-temperature, low-pressure two-phase refrigerant. Then it enters the differential pressure pre-cooling heat exchanger 201 to release cold energy for pre-cooling. After the pressure is regulated by the pressure regulator 204, it enters the gas-liquid separator 102.

[0046] like Figure 5 As shown, when the refrigeration module 3 and the differential pressure precooling module 2 are used together, the compressor 101, condenser fan 104, precooling fan 202 and refrigeration fan 303 are working, the expansion valve switching valve 108, refrigeration switching valve 301, defrost bypass valve 306 and pressure regulator 204 are open, and other valves are closed.

[0047] Specifically, when the compressor is working normally, the temperature and pressure of the refrigerant are increased. After being cooled by the condenser fan 104 and the condenser 103, the refrigerant enters the liquid storage tank 105. After passing through the first branch of the liquid storage tank 105, it enters the expansion valve 106 for throttling, pressure reduction, and temperature reduction, forming a low-temperature, low-pressure gas-liquid two-phase fluid. Then, it enters the refrigeration heat exchanger 302 through the refrigeration switching valve 301, where the refrigeration fan 303 provides low-temperature cold air to the fruits and vegetables. The cold air continues to flow, passing through the defrost bypass valve 306 and then entering the pre-cooling heat exchanger 201, where the pre-cooling fan 202 provides low-temperature cold air for pre-cooling the fruits and vegetables. Finally, after the pressure is adjusted by the pressure regulator 204, it flows back to the gas-liquid separator 102.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A cold storage refrigeration system with differential pressure precooling, characterized in that: It includes a cold storage unit, an outdoor unit module, a differential pressure pre-cooling module, and a refrigeration module, wherein the differential pressure pre-cooling module is installed in one area of ​​the cold storage unit; The outdoor unit module includes a compressor, a gas-liquid separator, a condenser, a condensing fan, a liquid storage tank, an expansion valve, a bypass switching valve, and an expansion valve switching valve. The inlet of the compressor is connected to the gas-liquid separator, and the outlet is connected to the condenser. The inlet of the gas-liquid separator serves as the cold storage output pipeline. The condensing fan is used for heat dissipation of the condenser. The outlet of the condenser is connected to the liquid storage tank. The first outlet of the liquid storage tank is connected to the expansion valve and the expansion valve switching valve, and the second outlet is connected to the bypass switching valve. The outlet of the expansion valve switching valve and the outlet of the bypass switching valve are combined to serve as the cold storage input pipeline. The differential pressure precooling module includes a precooling heat exchanger, a precooling fan, a precooling switching valve, and a pressure regulator. The first branch of the cold storage input pipeline is connected to the inlet of the precooling heat exchanger through the precooling switching valve. The precooling fan is used for the cold capacity output of the precooling heat exchanger. The outlet of the precooling heat exchanger is connected to the pressure regulator. The outlet of the pressure regulator is connected to the cold storage output pipeline. The refrigeration module includes a refrigeration switching valve, a refrigeration heat exchanger, a refrigeration fan, a defrost expansion valve, a defrost switching valve, a defrost bypass valve, and a refrigeration outlet switching valve. The second branch of the cold storage input pipeline is connected to the inlet of the refrigeration heat exchanger through the refrigeration switching valve, and the refrigeration fan is used for the cooling capacity output of the refrigeration heat exchanger. The outlet of the refrigeration heat exchanger is divided into three paths. The first path is connected to the cold storage output pipeline through the refrigeration outlet switching valve. The second path is connected to the inlet of the precooling heat exchanger through the defrost switching valve and the defrost expansion valve. The third path is connected to the inlet of the precooling heat exchanger through the defrost bypass valve. When the refrigeration module and the differential pressure precooling module are running together, the compressor, condenser fan, precooling fan and refrigeration fan are working. The expansion valve switching valve, refrigeration switching valve, defrost bypass valve and pressure regulator are open, and other valves are closed.

2. The cold storage refrigeration system with differential pressure precooling according to claim 1, characterized in that: When the refrigeration module defrosts, the compressor and precooling fan operate, the bypass switching valve, refrigeration switching valve, defrosting switching valve and pressure regulator open, and other valves close.

3. The cold storage refrigeration system with differential pressure precooling according to claim 2, characterized in that: When the differential pressure precooling module operates independently, the compressor, condenser fan, and precooling fan are working, the expansion valve switching valve, precooling switching valve, and pressure regulator are open, and other valves and the refrigeration fan are closed.

4. The cold storage refrigeration system with differential pressure precooling according to claim 1, 2, or 3, characterized in that: When the refrigeration module operates independently, the compressor, condenser fan, and refrigeration fan work, the expansion valve switching valve, refrigeration switching valve, and refrigeration outlet switching valve are open, and other valves and the pre-cooling fan are closed.

Images