Refrigerant control systems, methods, devices, apparatuses, and media at low refrigeration loads

Abstract

This application provides a refrigerant control system, method, apparatus, equipment, and medium under low-load refrigeration conditions, belonging to the field of air conditioning and refrigeration control technology. Each outdoor heat exchanger has an independent liquid temperature sensor to independently collect the liquid pipe temperature of each heat exchanger and detect the accumulation of refrigerant in the heat exchanger. The liquid temperature sensor is arranged on the lowest distribution pipe of the distributor assembly. Electronic expansion valves are installed on the liquid main pipes of the upper and lower finned heat exchangers to adjust the resistance of the upper and lower refrigerant flow pipes. Combined with the refrigerant control method in the embodiments of this application, the resistance of the refrigerant flow pipes of the heat exchangers can be adjusted by controlling and regulating the electronic expansion valves. A one-way valve is installed on the electronic expansion valves to remove refrigerant that accumulates in the lower finned heat exchanger due to the change in the resistance of the upper electronic expansion valve under low-load refrigeration conditions, thereby reducing the flow resistance of the lower refrigerant pipes, increasing the flow area, and reducing the flow resistance.

Description

Technical Field

[0001] This application belongs to the field of air conditioning and refrigeration control technology, and specifically relates to a refrigerant control system, method, device, equipment and medium under low refrigeration load. Background Technology

[0002] Variable frequency air conditioning systems are becoming increasingly popular due to their superior part-load energy efficiency compared to fixed frequency air conditioners, especially multi-split inverter systems, which account for more than 50% of the central air conditioning market. Currently, there is a clear trend towards larger commercial multi-split air conditioning systems, with single-module capacities approaching 50HP, leading to a gradual increase in heat exchanger height to approximately 1.6 meters and more than 40 U-tubes. Variable frequency multi-split systems have a wide load variation range, with compressor frequencies ranging from 14-160 rpm and a minimum indoor unit cooling capacity of approximately 1.8kW. These factors necessitate that the outdoor unit adjusts its cooling capacity within a 5%-100% load range during operation. Under low-load cooling conditions, the indoor unit load is small, and during operation, the refrigerant often accumulates at the bottom of the outdoor unit's heat exchanger and does not participate in operation. This results in insufficient refrigerant flow in the indoor unit under low load, and even with its expansion valve at maximum opening, it cannot achieve the required superheat to meet cooling capacity. Simultaneously, refrigerant accumulates at the bottom of the outdoor heat exchanger, occupying some of the heat exchange piping space, reducing the heat exchange area and decreasing heat transfer efficiency. This leads to increased high-pressure during cooling, and in extreme cases, may even trigger high-pressure protection. The conventional method is to tolerate refrigerant accumulation at the bottom by reducing fan speed and increasing high-pressure to enhance refrigerant delivery capacity and alleviate refrigerant shortages in the indoor unit. Summary of the Invention

[0003] In view of the above problems, this application proposes a refrigerant control system, method, apparatus, equipment, and medium for low-load refrigeration. Under low-load refrigeration conditions, it can eliminate refrigerant that accumulates in the lower finned heat exchanger due to changes in the resistance of the upper electronic expansion valve, reduce the flow resistance of the lower refrigerant pipeline, increase the flow area, and reduce the flow resistance.

[0004] One embodiment of this application provides a refrigerant control system under low refrigeration load, including:

[0005] The outdoor system includes an upper finned heat exchanger, a lower finned heat exchanger, a first electronic expansion valve, a second electronic expansion valve, a first liquid temperature sensor, a second liquid temperature sensor, and an outdoor temperature sensor.

[0006] The outdoor temperature sensor is installed on the external pipe of the heat exchanger to obtain the outdoor temperature.

[0007] A second liquid temperature sensor and a first liquid temperature sensor are respectively installed on the refrigerant channels of the upper finned heat exchanger and the lower finned heat exchanger.

[0008] The refrigerant channels of the upper finned heat exchanger and the lower finned heat exchanger are respectively connected to the second electronic expansion valve and the first electronic expansion valve through the second distributor assembly and the first distributor assembly.

[0009] In one embodiment, the system further includes:

[0010] The first end of the first distributor assembly is connected to multiple refrigerant pipes to the upper finned heat exchanger, and the second end of the first distributor assembly is connected to the second end of the first electronic expansion valve.

[0011] The first end of the first electronic expansion valve is connected to the liquid-side shut-off valve.

[0012] In one embodiment, the system further includes:

[0013] One-way valves are also connected in parallel at both ends of the first electronic expansion valve;

[0014] The first end of the one-way valve is connected to the second end of the first electronic expansion valve and to the second end of the first distributor assembly;

[0015] The second end of the one-way valve is connected to the first end of the first electronic expansion valve and is also connected to the liquid-side shut-off valve.

[0016] In one embodiment, the system further includes:

[0017] The first end of the second distributor assembly is connected to multiple refrigerant pipes to the upper finned heat exchanger, and the second end of the second distributor assembly is connected to the second end of the second electronic expansion valve.

[0018] The first end of the second electronic expansion valve is connected to the liquid-side shut-off valve.

[0019] In one embodiment, the system further includes:

[0020] The upper finned heat exchanger is connected to the first end of the lower finned heat exchanger and to the first end of the four-way valve. The second end of the four-way valve is connected to the second end of the gas-liquid separator.

[0021] The third end of the four-way valve is connected to the first end of the gas-side shut-off valve, and the fourth end of the four-way valve is connected to the second end of the compressor.

[0022] In one embodiment, the system further includes:

[0023] The first end of the compressor is connected to the first end of the gas-liquid separator.

[0024] Based on the same inventive concept, another aspect of this application provides a refrigerant control method under low refrigeration load, applied in a refrigerant control system under low refrigeration load, including:

[0025] The outdoor ambient temperature is collected using an outdoor temperature sensor; the temperature of the first distribution pipe of the lower finned heat exchanger from top to bottom is collected using a first liquid temperature sensor; and the temperature of the second distribution pipe of the upper finned heat exchanger is collected using a second liquid temperature sensor.

[0026] A first difference is determined based on the temperature of the first distribution pipe and the temperature of the second distribution pipe, and a second difference is determined based on the temperature of the second distribution pipe and the outdoor ambient temperature.

[0027] The difference condition is determined based on the first difference and the second difference, and the electronic expansion valve is adjusted to balance the refrigerant according to the difference condition determination result.

[0028] Furthermore, the step of determining the difference condition based on the first difference and the second difference includes:

[0029] Set a first threshold A and a second threshold B;

[0030] When the first difference is greater than or equal to the first threshold A, and the second difference is less than or equal to the second threshold B, the refrigerant balance anti-aggregation control is initiated.

[0031] Furthermore, the refrigerant equilibrium anti-aggregation control includes:

[0032] When the first difference is greater than or equal to the first threshold A and the second difference is less than or equal to the second threshold B, the second electronic expansion valve is controlled to close.

[0033] The second electronic expansion valve stops closing when the first difference is less than the first threshold and the second difference is greater than the second threshold B.

[0034] When the first difference is less than the second difference, the second electronic expansion valve is controlled to open until the first difference is greater than or equal to the second difference, at which point the second electronic expansion valve is controlled to stop opening.

[0035] Based on the same inventive concept, another aspect of the embodiments of this application provides a refrigerant control device under low refrigeration load, comprising:

[0036] The detection unit is used to collect the outdoor ambient temperature based on the outdoor temperature sensor, collect the temperature of the first distribution pipe of the lower finned heat exchanger from top to bottom based on the first liquid temperature sensor, and collect the temperature of the second distribution pipe of the upper finned heat exchanger based on the second liquid temperature sensor.

[0037] The calculation unit is used to determine a first difference based on the temperature of the first distribution pipe and the temperature of the second distribution pipe, and to determine a second difference based on the temperature of the second distribution pipe and the outdoor ambient temperature.

[0038] The control unit is used to determine the difference condition based on the first difference and the second difference, and adjust the electronic expansion valve to balance the refrigerant according to the difference condition determination result.

[0039] Based on the same inventive concept, another aspect of the embodiments of this application provides an electronic device, including: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0040] Memory, which stores computer programs;

[0041] When the processor executes the program stored in memory, it implements a refrigerant control method under low refrigeration load.

[0042] Based on the same inventive concept, another aspect of the embodiments of this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements a refrigerant control method under low refrigeration load.

[0043] The beneficial effects of this application are:

[0044] Based on the above technical solution, each outdoor heat exchanger has an independent liquid temperature sensor to independently collect the liquid pipe temperature of each heat exchanger and detect the refrigerant accumulation in the heat exchanger. The liquid temperature sensor is arranged on the lowest distribution pipe of the distributor assembly. Electronic expansion valves are installed on the liquid main pipes of the upper and lower finned heat exchangers to adjust the resistance of the upper and lower refrigerant flow pipes. Thus, it can be seen that the refrigerant control method in this embodiment can adjust the resistance of the refrigerant flow pipes of the heat exchanger by controlling and adjusting the electronic expansion valve. A one-way valve is installed on the electronic expansion valve. Under low-load cooling conditions, it can eliminate the refrigerant that accumulates in the lower finned heat exchanger to change the resistance of the upper electronic expansion valve, reduce the flow resistance of the lower refrigerant pipe, increase the flow area, and reduce the flow resistance.

[0045] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description and the accompanying drawings. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 A structural diagram of a refrigerant control system under low refrigeration load is shown.

[0048] Figure 2 A flowchart of a refrigerant control method under low refrigeration load is shown;

[0049] Figure 3 A schematic diagram of a refrigerant control device under low refrigeration load is shown.

[0050] Figure 4 A schematic diagram of an electronic device is shown. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.

[0053] This application provides an embodiment of a refrigerant control system for low-load refrigeration. (See also...) Figure 1 ,include:

[0054] The outdoor system includes an upper finned heat exchanger 72, a lower finned heat exchanger 71, a first electronic expansion valve 41, a second electronic expansion valve 42, a first liquid temperature sensor 51, a second liquid temperature sensor 52, and an outdoor temperature sensor 12.

[0055] The outdoor temperature sensor 12 is installed on the external pipe of the heat exchanger to obtain the outdoor temperature.

[0056] A second liquid temperature sensor 52 and a first liquid temperature sensor 51 are respectively installed on the refrigerant channels of the upper finned heat exchanger 72 and the lower finned heat exchanger 71.

[0057] The refrigerant channels of the upper finned heat exchanger 72 and the lower finned heat exchanger 71 are respectively connected to the second electronic expansion valve 42 and the first electronic expansion valve 41 through the second distributor assembly 62 and the first distributor assembly 61.

[0058] In one embodiment, the system further includes:

[0059] The first end of the first distributor assembly 61 is connected to a plurality of refrigerant pipes to the upper finned heat exchanger 71, and the second end of the first distributor assembly 61 is connected to the second end of the first electronic expansion valve 41.

[0060] The first end of the first electronic expansion valve 41 is connected to the liquid-side shut-off valve 11.

[0061] In one embodiment, the system further includes:

[0062] One-way valves 8 are also connected in parallel at both ends of the first electronic expansion valve 41;

[0063] The first end of the one-way valve 8 is connected to the second end of the first electronic expansion valve 41 and to the second end of the first distributor assembly 61.

[0064] The second end of the one-way valve 8 is connected to the first end of the first electronic expansion valve 41 and is also connected to the liquid-side shut-off valve 11.

[0065] In one embodiment, the system further includes:

[0066] The first end of the second distributor assembly 62 is connected to multiple refrigerant pipes to the upper finned heat exchanger 72, and the second end of the second distributor assembly 62 is connected to the second end of the second electronic expansion valve 42.

[0067] The first end of the second electronic expansion valve 42 is connected to the liquid-side shut-off valve 11.

[0068] In one embodiment, the system further includes:

[0069] The upper finned heat exchanger 72 is connected to the first end of the lower finned heat exchanger 71 and is also connected to the first end of the four-way valve 3. The second end of the four-way valve 3 is connected to the second end of the gas-liquid separator 2.

[0070] The third end of the four-way valve 3 is connected to the first end of the gas-side shut-off valve 10, and the fourth end of the four-way valve 3 is connected to the second end of the compressor 1.

[0071] In one embodiment, the system further includes:

[0072] The first end of the compressor 1 is connected to the first end of the gas-liquid separator 2.

[0073] The refrigerant control system under low refrigeration load in the embodiments of this specification will be described in detail below with reference to the accompanying drawings.

[0074] See Figure 1 The control system in this embodiment has two outdoor heat exchangers or the outdoor heat exchangers are divided into two parts. The purpose of setting two heat exchangers is to allow for individual adjustment of the refrigerant flow resistance of each part of the heat exchanger, so as to prevent refrigerant from accumulating in the lower part of the heat exchanger. Each outdoor heat exchanger or the part of the outdoor heat exchanger is arranged vertically or divided into two parts, such as the upper finned heat exchanger 72 and the lower finned heat exchanger 71 in this embodiment. The vertical arrangement is because the refrigerant is more likely to accumulate in the lower part due to gravity. The vertical distribution is to ensure that the refrigerant accumulated in the lower finned heat exchanger 71 is discharged after the resistance is adjusted.

[0075] Each outdoor heat exchanger or each part of the outdoor heat exchanger has an independent distributor assembly, which in this embodiment is a first distributor assembly 61 and a second distributor assembly 62. The independent distributor assembly is part of the refrigerant flow channel and can achieve independent adjustment of resistance.

[0076] Each outdoor heat exchanger or each part of the outdoor heat exchanger has an independent liquid temperature sensor, including the first liquid temperature sensor 51 and the second liquid temperature sensor 52 in this embodiment. The independent refrigerant liquid temperature sensor is to independently collect the liquid pipe temperature of each part of the heat exchanger and detect the accumulation of refrigerant in the heat exchanger.

[0077] The liquid temperature sensor is located on the lowest distribution pipe of the distributor assembly. Due to gravity, the refrigerant liquid mainly accumulates in the lower part of the heat exchanger. Therefore, the accumulation of refrigerant liquid is characterized by the lowest liquid pipe of each heat exchanger section.

[0078] A second electronic expansion valve 42 is installed on the liquid main of the upper finned heat exchanger 72 to adjust the resistance of the upper refrigerant flow pipeline; a first electronic expansion valve 41 is installed on the liquid pipeline of the lower finned heat exchanger 71 to adjust the resistance of the lower refrigerant flow pipeline.

[0079] In some embodiments, to reduce the resistance of the liquid pipeline in the lower finned heat exchanger 71, a check valve 8 is connected to the first electronic expansion valve 41. The direction of the check valve 8 is consistent with the direction of the liquid outlet. Due to the influence of gravity, the refrigerant pipeline usually accumulates in the lower part. It is common practice to change the resistance of the upper part of the electronic expansion valve to discharge the accumulated refrigerant in the lower finned heat exchanger. In order to reduce the flow resistance of the lower part of the refrigerant pipeline, the check valve 8 can be connected in parallel with the first electronic expansion valve 41 to increase the flow area and reduce the flow resistance.

[0080] Based on the same inventive concept, another aspect of this application provides a refrigerant control method under low refrigeration load, applied in a refrigerant control system under low refrigeration load. See [link to relevant documentation]. Figure 2 ,include:

[0081] S1: The outdoor ambient temperature is collected based on the outdoor temperature sensor; the temperature of the first distribution pipe of the lower finned heat exchanger from top to bottom is collected based on the first liquid temperature sensor; the temperature of the second distribution pipe of the upper finned heat exchanger is collected based on the second liquid temperature sensor.

[0082] S2: Determine a first difference based on the temperature of the first distribution pipe and the temperature of the second distribution pipe, and determine a second difference based on the temperature of the second distribution pipe and the outdoor ambient temperature;

[0083] S3: Based on the first difference and the second difference, a difference condition determination is made, and the electronic expansion valve is adjusted to balance the refrigerant according to the difference condition determination result.

[0084] Specifically, in step S3, the difference condition determination based on the first difference and the second difference includes:

[0085] Set a first threshold A and a second threshold B;

[0086] When the first difference is greater than or equal to the first threshold A, and the second difference is less than or equal to the second threshold B, the refrigerant balance anti-aggregation control is initiated.

[0087] Specifically, the refrigerant equilibrium anti-aggregation control includes:

[0088] When the first difference is greater than or equal to the first threshold A and the second difference is less than or equal to the second threshold B, the second electronic expansion valve is controlled to close.

[0089] The second electronic expansion valve stops closing when the first difference is less than the first threshold and the second difference is greater than the second threshold B.

[0090] When the first difference is less than the second difference, the second electronic expansion valve is controlled to open until the first difference is greater than or equal to the second difference, at which point the second electronic expansion valve is controlled to stop opening.

[0091] Specifically, the outdoor temperature sensor 12 collects the outdoor ambient temperature Ta; the first liquid temperature sensor 51 collects the temperature T1 of the first distribution pipe in the vertical direction from bottom to top on the lower finned heat exchanger 71; and the first liquid temperature sensor 51 collects the temperature T2 of the second distribution pipe in the vertical direction at the lowest point on the upper finned heat exchanger 72.

[0092] The first difference Δt1 = T1 - T2 is calculated based on the temperature T1 of the first distribution pipe and the temperature T2 of the second distribution pipe; the second difference Δt2 = T2 - Ta is determined based on the temperature T2 of the second distribution pipe and the outdoor ambient temperature Ta; the severity of refrigerant accumulation in the bottom heat exchanger is judged by the difference in liquid pipe temperature and the difference between the bottom liquid pipe temperature and the ambient temperature.

[0093] Specifically, a first threshold A and a second threshold B are set. When the first difference Δt1 ≥ the first threshold A and the second difference Δt2 ≤ the second threshold B, the electronic expansion valve 42 is gradually closed. Closing the electronic expansion valve 42 increases the resistance of the upper heat exchanger, forcibly discharging the refrigerant accumulated in the lower heat exchanger. The first threshold A and the second threshold B are based on experimental test thresholds.

[0094] The second electronic expansion valve 42 stops closing when the first difference Δt1 is less than the first threshold A, or the second difference Δt2 is greater than the second threshold B.

[0095] When the temperature of the first distribution pipe T1 is less than the temperature of the second distribution pipe T2, the second electronic expansion valve 42 is opened until the temperature of the first distribution pipe T1 is greater than or equal to the temperature of the second distribution pipe T2.

[0096] It should be noted that the control methods used in this application are all implemented by loading software code into hardware devices. The device running the software can be any one or more of the following controllers: microcontroller programmable logic controller (PLC), field-programmable gate array (FPGA).

[0097] By controlling and adjusting the electronic expansion valve, the resistance of the refrigerant flow pipeline in the heat exchanger can be adjusted. A one-way valve is installed on the electronic expansion valve to remove the refrigerant that accumulates in the lower finned heat exchanger due to the change in the resistance of the upper electronic expansion valve, thereby reducing the flow resistance of the lower refrigerant pipeline, increasing the flow area, and reducing the flow resistance.

[0098] Based on the same inventive concept, another aspect of the embodiments of this application provides a refrigerant control device under low refrigeration load, see [link to relevant documentation]. Figure 3 ,include:

[0099] The detection unit 201 is used to collect the outdoor ambient temperature based on the outdoor temperature sensor, collect the temperature of the first distribution pipe of the lower finned heat exchanger from top to bottom based on the first liquid temperature sensor, and collect the temperature of the second distribution pipe of the upper finned heat exchanger based on the second liquid temperature sensor.

[0100] The calculation unit 202 is used to determine a first difference based on the temperature of the first distribution pipe and the temperature of the second distribution pipe, and to determine a second difference based on the temperature of the second distribution pipe and the outdoor ambient temperature.

[0101] The control unit 203 is used to determine the difference condition based on the first difference and the second difference, and adjust the electronic expansion valve to perform balanced control of the refrigerant according to the difference condition determination result.

[0102] Based on the same inventive concept, another aspect of the embodiments of this application provides an electronic device, including: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0103] Memory, which stores computer programs;

[0104] When the processor executes the program stored in memory, it implements a refrigerant control method under low refrigeration load.

[0105] Based on the same inventive concept, another aspect of the embodiments of this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements a refrigerant control method under low refrigeration load.

[0106] Based on the same inventive concept, this disclosure also provides an electronic device 161, see [link to previous document]. Figure 4 It includes a processor 164, a communication interface 165, a memory 162, and a communication bus, wherein the processor 164, the communication interface 165, and the memory 162 communicate with each other through the communication bus;

[0107] Memory 162 stores computer program 163;

[0108] When the processor 164 executes the program stored in the memory 162, it implements a refrigerant control method under low refrigeration load.

[0109] The aforementioned communication bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc.

[0110] The communication interface 165 is used for communication between the aforementioned electronic device 161 and other devices.

[0111] The memory 162 may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory 162 may also be at least one storage device located remotely from the aforementioned processor 164.

[0112] The processor 164 mentioned above can be a general-purpose processor 164, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0113] Based on the same inventive concept, another aspect of the present disclosure provides a computer-readable storage medium storing a computer program 163, which, when executed by a processor 164, implements a refrigerant control method under low refrigeration load.

[0114] The computer-readable storage medium may be included in the device / apparatus described in the above embodiments; or it may exist independently and not assembled into the device / apparatus. The computer-readable storage medium carries one or more programs that, when executed, implement the refrigerant control method under low-load refrigeration according to the embodiments of this disclosure.

[0115] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A refrigerant control system for low-load refrigeration, characterized in that, include: The outdoor system includes an upper finned heat exchanger (72), a lower finned heat exchanger (71), a first electronic expansion valve (41), a second electronic expansion valve (42), a first liquid temperature sensor (51), a second liquid temperature sensor (52), and an outdoor temperature sensor (12). The outdoor temperature sensor (12) is installed on the external pipe of the heat exchanger to obtain the outdoor temperature; A second liquid temperature sensor (52) and a first liquid temperature sensor (51) are respectively installed on the refrigerant channels of the upper finned heat exchanger (72) and the lower finned heat exchanger (71). The refrigerant passages of the upper finned heat exchanger (72) and the lower finned heat exchanger (71) are respectively connected to the second electronic expansion valve (42) and the first electronic expansion valve (41) through the second distributor assembly (62) and the first distributor assembly (61).

2. The control system according to claim 1, characterized in that, The system also includes: The first end of the first distributor assembly (61) is connected to a plurality of refrigerant pipes to the upper finned heat exchanger (71), and the second end of the first distributor assembly (61) is connected to the second end of the first electronic expansion valve (41). The first end of the first electronic expansion valve (41) is connected to the liquid-side shut-off valve (11).

3. The control system according to claim 1 or 2, characterized in that, The system also includes: One-way valves (8) are also connected in parallel at both ends of the first electronic expansion valve (41). The first end of the one-way valve (8) is connected to the second end of the first electronic expansion valve (41) and to the second end of the first distributor assembly (61); The second end of the one-way valve (8) is connected to the first end of the first electronic expansion valve (41) and is connected to the liquid-side shut-off valve (11).

4. The control system according to claim 1, characterized in that, The system also includes: The first end of the second distributor assembly (62) is connected to multiple refrigerant pipes to the upper finned heat exchanger (72), and the second end of the second distributor assembly (62) is connected to the second end of the second electronic expansion valve (42); The first end of the second electronic expansion valve (42) is connected to the liquid-side shut-off valve (11).

5. The control system according to claim 1, characterized in that, The system also includes: The upper finned heat exchanger (72) is connected to the first end of the lower finned heat exchanger (71) and is also connected to the first end of the four-way valve (3). The second end of the four-way valve (3) is connected to the second end of the gas-liquid separator (2). The third end of the four-way valve (3) is connected to the first end of the gas-side shut-off valve (10), and the fourth end of the four-way valve (3) is connected to the second end of the compressor (1).

6. The control system according to claim 5, characterized in that, The system also includes: The first end of the compressor (1) is connected to the first end of the gas-liquid separator (2).

7. A refrigerant control method under low refrigeration load, applied in the refrigerant control system under low refrigeration load according to any one of claims 1 to 6, characterized in that, include: The outdoor ambient temperature is collected based on an outdoor temperature sensor, and the temperature of the first distribution pipe from top to bottom of the lower finned heat exchanger is collected based on a first liquid temperature sensor. The temperature of the second distribution pipe of the upper finned heat exchanger is collected based on the second liquid temperature sensor. A first difference is determined based on the temperature of the first distribution pipe and the temperature of the second distribution pipe, and a second difference is determined based on the temperature of the second distribution pipe and the outdoor ambient temperature. The difference condition is determined based on the first difference and the second difference, and the electronic expansion valve is adjusted to balance the refrigerant according to the difference condition determination result.

8. The method according to claim 7, characterized in that, The step of determining the difference condition based on the first difference and the second difference includes: Set a first threshold A and a second threshold B; When the first difference is greater than or equal to the first threshold A, and the second difference is less than or equal to the second threshold B, the refrigerant balance anti-aggregation control is initiated.

9. The method according to claim 8, characterized in that, The refrigerant equalization and anti-aggregation control includes: When the first difference is greater than or equal to the first threshold A and the second difference is less than or equal to the second threshold B, the second electronic expansion valve is controlled to close. The second electronic expansion valve stops closing when the first difference is less than the first threshold and the second difference is greater than the second threshold B. When the first difference is less than the second difference, the second electronic expansion valve is controlled to open until the first difference is greater than or equal to the second difference, at which point the second electronic expansion valve is controlled to stop opening.

10. A refrigerant control device under low refrigeration load, characterized in that, include: The detection unit is used to collect the outdoor ambient temperature based on the outdoor temperature sensor and to collect the temperature of the first distribution pipe from top to bottom of the lower finned heat exchanger based on the first liquid temperature sensor. The temperature of the second distribution pipe of the upper finned heat exchanger is collected based on the second liquid temperature sensor. The calculation unit is used to determine a first difference based on the temperature of the first distribution pipe and the temperature of the second distribution pipe, and to determine a second difference based on the temperature of the second distribution pipe and the outdoor ambient temperature. The control unit is used to determine the difference condition based on the first difference and the second difference, and adjust the electronic expansion valve to balance the refrigerant according to the difference condition determination result.

11. An electronic device, characterized in that, include: The processor, communication interface, memory, and communication bus are connected, with the processor, communication interface, and memory communicating with each other via the communication bus. Memory, which stores computer programs; When the processor executes the program stored in the memory, it implements the refrigerant control method under low refrigeration load as described in any one of claims 7 to 9.

12. A computer-readable storage medium, characterized in that, The device contains a computer program that, when executed by a processor, implements the refrigerant control method under low refrigeration load as described in any one of claims 7 to 9.

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