Refrigerator defrosting control method and system, refrigerator control method and system

Abstract

Embodiments of the present application provide a cold storage defrosting control method and system, and a cold storage control method and system, which solve the problem of suction pressure fluctuation caused by improper discharge of defrosting liquid. The cold storage defrosting control method comprises: closing a first liquid supply electromagnetic valve to perform defrosting; opening a first gas return electromagnetic valve and a defrosting unit, and evacuating refrigerant in the defrosting unit after a first preset time; after the refrigerant is evacuated, closing the first gas return electromagnetic valve and the defrosting unit; opening a first hot gas electromagnetic valve to perform defrosting, and closing the first hot gas electromagnetic valve after a second preset time; opening a first defrosting liquid return valve to perform liquid return, and closing the first defrosting liquid return valve after a third preset time; and repeating the above steps after a fourth preset time.

Description

TECHNICAL FIELD

[0001] The present application relates to the defrosting technical field, and in particular to a cold storage defrosting control method and system and a cold storage control method and system. BACKGROUND

[0002] The temperature of the cold storage warehouse is below 0 degrees Celsius, and the evaporator of the cold storage warehouse is in a low-temperature and high-humidity environment for a long time, which is very easy to frost. The frosting of the evaporator will reduce the heat exchange performance, reduce the evaporation temperature, reduce the energy efficiency of the unit, and increase the energy consumption. Therefore, defrosting of the cold storage is an important problem in the design of the cold storage. The current defrosting methods of the cold storage include electric defrosting, water defrosting, and hot gas defrosting. Among them, the hot gas defrosting introduces refrigerant from the inside of the refrigerant, which does not consume additional electric energy compared with electric heating defrosting, and the defrosting is uniform. However, if the liquid discharge of the hot gas defrosting is not smooth, it is easy to cause liquid suction or suction pressure fluctuation of the compressor, affecting the reliability of the system.

[0003] The traditional hot gas defrosting refrigeration system has two liquid discharge methods after the defrosting is completed: the defrosting liquid of the direct expansion system is discharged to the liquid discharge barrel, and the system needs to additionally increase the liquid discharge barrel, which is poor in economy; or enters other cold air fans, which is easy to cause liquid suction after starting if the control is not proper; the defrosting liquid of the pump liquid supply system is discharged to the low-pressure circulating liquid storage barrel, which is easy to cause suction pressure fluctuation, affecting the operation stability of the unit. SUMMARY

[0004] Therefore, the present application provides a cold storage defrosting control method and system and a cold storage control method and system, which solve the problem of suction pressure fluctuation caused by improper defrosting liquid discharge.

[0005] In a first aspect, a cold storage defrosting control method provided by an embodiment of the present application comprises:

[0006] closing the first liquid supply electromagnetic valve to perform defrosting;

[0007] opening the first gas return electromagnetic valve and the defrosting unit, and evacuating the refrigerant in the defrosting unit after a first preset time;

[0008] after the refrigerant is evacuated, closing the first gas return electromagnetic valve and the defrosting unit;

[0009] opening the first hot gas electromagnetic valve to perform defrosting, and closing the first hot gas electromagnetic valve after a second preset time;

[0010] opening the first defrosting liquid return valve to perform liquid return, and closing the first defrosting liquid return valve after a third preset time;

[0011] repeating the above steps after a fourth preset time.

[0012] In one embodiment, before the closing of the first liquid supply electromagnetic valve to perform defrosting, the method further comprises:

[0013] detecting the running state of the compressor unit, and determining whether the compressor unit has a compressor running;

[0014] if no compressor is running, starting the compressor;

[0015] In an embodiment, the starting the first hot gas solenoid valve to defrost includes: starting the first hot gas solenoid valve, and the hot gas discharged by the compressor unit enters the defrosting unit through the hot gas pipeline, and the hot gas entering the defrosting unit is condensed into high-pressure liquid after absorbing heat of the frost layer.

[0016] In an embodiment, the starting the first defrosting liquid return valve to return liquid includes: starting the first defrosting liquid return valve, and the high-pressure liquid after condensation enters the intercooler through the liquid discharge pipeline.

[0017] In a second aspect, an embodiment of the present application provides a cold storage control method, which comprises the cold storage defrosting control method.

[0018] In an embodiment, the cold storage control method comprises a refrigeration control method, and the refrigeration control method comprises:

[0019] the gas discharged by the compressor unit is condensed into high-pressure liquid through the condenser and enters the liquid accumulator;

[0020] the gas-liquid mixture in the liquid accumulator enters the intercooler through the throttling valve to be separated into gas and liquid, the separated gas returns to the compressor gas inlet, and the separated liquid enters the refrigeration unit through the liquid supply pipeline.

[0021] In an embodiment, the cold storage control method further comprises a refrigeration control method, and the refrigeration control method comprises:

[0022] opening or closing the second liquid supply solenoid valve and the second gas return solenoid valve based on the warehouse temperature;

[0023] opening or closing the refrigeration unit based on the warehouse temperature;

[0024] closing the second hot gas solenoid valve and the second defrosting liquid return valve.

[0025] In an embodiment, the opening or closing the second liquid supply solenoid valve and the second gas return solenoid valve based on the warehouse temperature comprises:

[0026] when the warehouse temperature is greater than the upper limit of the warehouse temperature, opening the second liquid supply solenoid valve and the second gas return solenoid valve;

[0027] when the warehouse temperature is less than the lower limit of the warehouse temperature, closing the second liquid supply solenoid valve and the second gas return solenoid valve;

[0028] When the warehouse temperature is greater than or equal to the lower limit of the warehouse temperature and less than or equal to the upper limit of the warehouse temperature, the second liquid supply electromagnetic valve and the second gas return electromagnetic valve remain unchanged.

[0029] In an embodiment, the opening or closing of the refrigeration unit based on the warehouse temperature comprises:

[0030] When the warehouse temperature is greater than the upper limit of the warehouse temperature, the refrigeration unit is opened;

[0031] When the warehouse temperature is less than the lower limit of the warehouse temperature, the refrigeration unit is closed;

[0032] When the warehouse temperature is less than or equal to the upper limit of the warehouse temperature and greater than or equal to the lower limit of the warehouse temperature, the refrigeration unit remains unchanged.

[0033] In a third aspect, an embodiment of the present application provides a cold storage defrosting control system, comprising: a defrosting unit, an intermediate cooler, a compressor unit; and

[0034] A first liquid supply electromagnetic valve is arranged between the defrosting unit and the outlet of the intermediate cooler.

[0035] A first gas return electromagnetic valve is arranged between the defrosting unit and the compressor unit.

[0036] A first hot gas electromagnetic valve is arranged between the defrosting unit and the exhaust port of the compressor unit.

[0037] A first defrosting liquid return valve is arranged between the defrosting unit and the inlet of the intermediate cooler.

[0038] In a fourth aspect, an embodiment of the present application provides a cold storage control system, comprising the cold storage defrosting control system.

[0039] In an embodiment, the cold storage control system comprises a refrigeration control system, and the refrigeration control system comprises: a condenser, a liquid accumulator and a refrigeration unit; and

[0040] A second liquid supply electromagnetic valve is arranged between the refrigeration unit and the outlet of the intermediate cooler.

[0041] A second gas return electromagnetic valve is arranged between the defrosting unit and the compressor unit.

[0042] A second hot gas electromagnetic valve is arranged between the refrigeration unit and the exhaust port of the compressor unit.

[0043] A second defrosting liquid return valve is arranged between the refrigeration unit and the inlet of the intermediate cooler.

[0044] In one embodiment, the refrigeration control system further includes a throttling valve disposed between the liquid receiver outlet and the intercooler inlet.

[0045] The present invention provides a cold storage defrosting control method, cold storage control method, cold storage defrosting control system, and cold storage control system, which differs from traditional plate intercoolers. During the refrigeration stage, the liquid in the liquid receiver of the cold storage control system provided by the present invention enters the intercooler for gas-liquid separation after being throttled and depressurized by a throttling valve. The separated liquid enters the air cooler for heat exchange, while the gas returns to the compressor's gas inlet. During defrosting, the defrosted liquid enters the intercooler from the defrosting unit, which does not cause fluctuations in suction pressure and affect the stability of the unit's operation. Attached Figure Description

[0046] Figure 1 The diagram shown is a structural schematic of a cold storage control system provided in an embodiment of the present invention.

[0047] Figure 2 The diagram shown is a flowchart of a cold storage defrosting control method according to an embodiment of the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] This embodiment provides a cold storage defrosting control system, such as Figure 1 As shown, the cold storage defrosting control system includes: a defrosting unit, an intercooler, a compressor unit, a first liquid supply solenoid valve V1.02, a first return gas solenoid valve V1.03, a first hot gas solenoid valve V1.04, and a first defrost return valve V1.01. Specifically, the first liquid supply solenoid valve V1.02 is located between the defrosting unit and the outlet of the intercooler; the first return gas solenoid valve V1.03 is located between the defrosting unit and the compressor unit; the first hot gas solenoid valve V1.04 is located between the defrosting unit and the exhaust port of the compressor unit; and the first defrost return valve V1.01 is located between the defrosting unit and the inlet of the intercooler.

[0050] This embodiment provides a cold storage control system, such as Figure 1As shown, the system includes the cold storage defrosting control system and refrigeration control system described in the above embodiments. The refrigeration control system includes: a condenser, a liquid receiver, a refrigeration unit, a second liquid supply solenoid valve V2.02, a second return gas solenoid valve V2.03, a second hot gas solenoid valve V2.04, and a second defrost return liquid valve V2.01. Specifically, the second liquid supply solenoid valve V2.02 is located between the outlet of the refrigeration unit and the intercooler; the second return gas solenoid valve V2.03 is located between the defrosting unit and the compressor unit; the second hot gas solenoid valve V2.04 is located between the exhaust port of the refrigeration unit and the compressor unit; and the second defrost return liquid valve V2.01 is located between the inlet of the refrigeration unit and the intercooler.

[0051] In one embodiment of the present invention, the cold storage control system further includes a throttling valve disposed between the outlet of the liquid receiver and the inlet of the intercooler. The cold storage control system also includes a hot gas pipeline, wherein one end of the first return gas solenoid valve V1.03 and one end of the second return gas solenoid valve V2.03 are connected to one end of the hot gas pipeline, and the other end of the hot gas pipeline is connected to the exhaust port of the compressor unit and the inlet of the condenser. The cold storage control system also includes a drain pipeline, wherein one end of the first defrost return liquid valve V1.01 and one end of the second defrost return liquid valve V2.01 are connected to the drain pipeline, and the other end of the drain pipeline is connected to the inlet of the intercooler. The cold storage control system also includes a supply pipeline, wherein one end of the first supply liquid solenoid valve V1.02 and one end of the second supply liquid solenoid valve V2.02 are connected to the supply pipeline, and the other end of the supply pipeline is connected to the outlet of the intercooler. The cold storage control system also includes a gas supply line and a suction line. One end of the gas supply line is connected to the inlet of the intercooler, and the other end is connected to the compressor unit. One end of the suction line is connected to the compressor unit, and the other end is connected to the first return gas solenoid valve V1.03.

[0052] In one embodiment of the present invention, the defrosting unit and the refrigeration unit can be either an evaporator or a fan cooler.

[0053] This embodiment provides a method for controlling defrosting in cold storage, such as... Figure 2 As shown, the defrosting control method for cold storage includes:

[0054] Step 01: Close the first liquid supply solenoid valve V1.02 to perform defrosting.

[0055] In addition, before closing the first liquid supply solenoid valve V1.02 to perform defrosting, the following steps are also included:

[0056] Detect the operating status of the compressor unit to determine whether a compressor is running.

[0057] If the compressor is not running, turn it on.

[0058] Step 02: Open the first return gas solenoid valve V1.03 and the defrosting unit, and after the first preset time, evacuate the refrigerant from the defrosting unit.

[0059] Step 03: After the refrigerant is evacuated, close the first return gas solenoid valve V1.03 and the defrosting unit;

[0060] Step 04: Open the first hot gas solenoid valve V1.04 to defrost, and close the first hot gas solenoid valve V1.04 after the second preset time;

[0061] Step 05: Open the first defrost return valve V1.01 to return liquid, and close the first defrost return valve V1.01 after the third preset time;

[0062] Step 06: Repeat the above steps after the fourth preset time. After one defrosting cycle (minutes), the defrosting process of the defrosting unit ends. One defrosting cycle is the sum of the first preset time, the second preset time, the third preset time, and the fourth preset time.

[0063] In this embodiment, the defrost liquid is discharged into the intercooler, which balances economy and reliability, solves the problem of defrost liquid discharge, and avoids suction pressure fluctuations.

[0064] In one embodiment of the present invention, the first hot gas solenoid valve V1.04 is opened, and the hot gas discharged from the compressor unit enters the defrosting unit through the hot gas pipeline. After absorbing the heat of the frost layer, the hot gas entering the defrosting unit condenses into a high-pressure liquid. The first defrosting return valve V1.01 is opened, and the condensed high-pressure liquid enters the intercooler through the drain pipeline.

[0065] This embodiment provides a cold storage control method, which includes the cold storage defrosting control method described in the above embodiment, and also includes a refrigeration control method. The refrigeration control method includes: the gas discharged from the compressor unit is condensed into a high-pressure liquid by the condenser and enters the liquid receiver; the gas-liquid mixture in the liquid receiver enters the intercooler for gas-liquid separation through the throttle valve; the separated gas returns to the compressor's gas supply port; and the separated liquid enters the refrigeration unit through the liquid supply pipeline.

[0066] In this embodiment, the liquid in the receiver is throttled and depressurized by the throttle valve before entering the intercooler for gas-liquid separation. The separated liquid enters the air cooler for heat exchange, while the gas returns to the compressor's gas inlet. During defrosting, the defrosted liquid enters the intercooler from the defrosting unit, which does not cause fluctuations in the suction pressure and affect the stability of the unit's operation.

[0067] In one embodiment of the present invention, the refrigeration control method includes: opening or closing the second liquid supply solenoid valve V2.02 and the second return gas solenoid valve V2.03 based on the warehouse temperature; opening or closing the refrigeration unit based on the warehouse temperature; and closing the second hot gas solenoid valve V2.04 and the second defrost return liquid valve V2.01.

[0068] Optionally, the step of opening or closing the second liquid supply solenoid valve V2.02 and the second return gas solenoid valve V2.03 based on the warehouse temperature includes:

[0069] When the warehouse temperature exceeds the upper limit of the warehouse temperature, the second liquid supply solenoid valve V2.02 and the second return gas solenoid valve V2.03 are opened;

[0070] When the warehouse temperature is lower than the lower limit of the warehouse temperature, close the second liquid supply solenoid valve V2.02 and the second return gas solenoid valve V2.03;

[0071] When the warehouse temperature is greater than or equal to the lower limit of the warehouse temperature and less than or equal to the upper limit of the warehouse temperature, the on / off state of the second liquid supply solenoid valve V2.02 and the second return gas solenoid valve V2.03 remains unchanged.

[0072] Optionally, the step of turning the refrigeration unit on or off based on the warehouse temperature includes:

[0073] When the warehouse temperature exceeds the upper limit of the warehouse temperature, the refrigeration unit is turned on.

[0074] When the warehouse temperature is below the lower limit of the warehouse temperature, the refrigeration unit is turned off;

[0075] When the warehouse temperature is less than or equal to the upper limit of the warehouse temperature and greater than or equal to the lower limit of the warehouse temperature, the switching state of the refrigeration unit remains unchanged.

[0076] In one embodiment of the present invention, a parallel screw compressor with two terminal air coolers is used as an example. Air cooler 1 is a refrigeration unit, and air cooler 2 is a defrosting unit. The control process of the refrigeration cycle and the defrosting cycle when air cooler 1 is refrigerating and air cooler 2 is defrosting is shown in the table below:

[0077]

[0078]

[0079] This embodiment provides a computer-readable storage medium storing a computer program, which, when executed by a processor, is used to implement the cold storage defrosting control method described above.

[0080] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention. It will be clearly understood by those skilled in the art that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0081] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0082] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. If the functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media capable of storing program checksums.

[0083] This embodiment provides an electronic device, including a memory and a processor. The memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the above-described cold storage defrosting control method.

[0084] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0085] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner.

[0086] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0087] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0088] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, top, bottom, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of the components in a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0089] 0. Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0090] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto.

[0091] Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention should be included within the protection scope of this invention. Therefore, the protection scope of this invention should be determined by the scope of the claims. The above description is merely a preferred embodiment of this invention and is not intended to limit the invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A method for controlling defrosting in cold storage, characterized in that, This is applied to a cold storage control system, which includes: a defrosting unit, an intercooler, and a compressor unit; and The first liquid supply solenoid valve is located between the defrosting unit and the outlet of the intercooler; The first return gas solenoid valve is located between the defrosting unit and the compressor unit; The first hot gas solenoid valve is located between the defrosting unit and the exhaust port of the compressor unit; The first defrosting return valve is located between the defrosting unit and the inlet of the intercooler; The cold storage control system further includes: a condenser, a liquid receiver, a refrigeration unit, a throttling valve, a gas supply line, and a suction line. The inlet of the condenser is connected to the exhaust port of the compressor unit. The throttling valve is located between the outlet of the liquid receiver and the inlet of the intercooler. One end of the gas supply line is connected to the inlet of the intercooler, and the other end is connected to the compressor unit. One end of the suction line is connected to the compressor unit, and the other end is connected to the first return gas solenoid valve. Control methods include: Detect the operating status of the compressor unit to determine whether a compressor is running. If the compressor is not running, turn it on; Close the first liquid supply solenoid valve to perform defrosting; Open the first return air solenoid valve and the defrosting unit to draw refrigerant from the defrosting unit through the intake pipe, and empty the refrigerant from the defrosting unit after a first preset time. After the refrigerant is evacuated, the first return gas solenoid valve and the defrosting unit are closed; Open the first hot gas solenoid valve to defrost, and close the first hot gas solenoid valve after a second preset time. Open the first defrost return valve to return liquid, and close the first defrost return valve after a third preset time. Repeat the above steps after the fourth preset time; When the first hot gas solenoid valve is opened, the hot gas discharged from the compressor unit enters the defrosting unit through the hot gas pipeline. After absorbing the heat of the frost layer, the hot gas entering the defrosting unit condenses into a high-pressure liquid. After the first defrosting return valve is opened, the condensed high-pressure liquid enters the intercooler through the drain pipeline, thus preventing fluctuations in the suction pressure and affecting the stability of the unit's operation. The gas discharged from the compressor unit is condensed into a high-pressure liquid by the condenser and enters the liquid receiver; the gas-liquid mixture in the liquid receiver enters the intercooler for gas-liquid separation through the throttle valve, the separated gas returns to the compressor's gas inlet through the gas supply line, and the separated liquid enters the refrigeration unit through the liquid supply line.

2. A cold storage control method, characterized in that, Including the cold storage defrosting control method described in claim 1 above.

3. The cold storage control method according to claim 2, characterized in that, The cold storage control system also includes: The second liquid supply solenoid valve is located between the outlet of the refrigeration unit and the intercooler. The second return gas solenoid valve is located between the defrosting unit and the compressor unit; The second hot gas solenoid valve is located between the exhaust port of the refrigeration unit and the compressor unit. The second defrosting return valve is located between the inlet of the refrigeration unit and the intercooler. The method further includes: a refrigeration control method; the refrigeration control method includes: The second liquid supply solenoid valve and the second gas return solenoid valve are opened or closed based on the warehouse temperature. The refrigeration unit is turned on or off based on the warehouse temperature; Close the second hot gas solenoid valve and the second defrosting return valve.

4. The cold storage control method according to claim 3, characterized in that, The method of opening or closing the second liquid supply solenoid valve and the second return gas solenoid valve based on the warehouse temperature includes: When the warehouse temperature exceeds the upper limit of the warehouse temperature, open the second liquid supply solenoid valve and the second return gas solenoid valve. When the warehouse temperature is lower than the lower limit of the warehouse temperature, close the second liquid supply solenoid valve and the second return gas solenoid valve. When the warehouse temperature is greater than or equal to the lower limit of the warehouse temperature and less than or equal to the upper limit of the warehouse temperature, the switching states of the second liquid supply solenoid valve and the second return gas solenoid valve remain unchanged.

5. The cold storage control method according to claim 4, characterized in that, The method of turning the refrigeration unit on or off based on the warehouse temperature includes: When the warehouse temperature exceeds the upper limit of the warehouse temperature, the refrigeration unit is turned on. When the warehouse temperature is below the lower limit of the warehouse temperature, the refrigeration unit is turned off; When the warehouse temperature is less than or equal to the upper limit of the warehouse temperature and greater than or equal to the lower limit of the warehouse temperature, the switching state of the refrigeration unit remains unchanged.

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