High-temperature refrigeration and air-conditioning system and control method

Abstract

The present invention relates to the technical field of air-conditioning systems, in particular to a high-temperature refrigeration and air-conditioning system and a control method, which aim to solve the problem of the discharge temperature of compressors of existing air-conditioning systems being excessively high in a high-temperature refrigeration mode. For this purpose, the high-temperature refrigeration and air-conditioning system provided by the present invention comprises an indoor heat exchanger, an outdoor heat exchanger, a four-way reversing valve, an electronic expansion valve and a compressor, wherein the indoor heat exchanger, the outdoor heat exchanger, the four-way reversing valve, the electronic expansion valve and the compressor form a closed-loop refrigerant circulation loop. The high-temperature refrigeration and air-conditioning system further comprises a solenoid valve, a capillary tube and an auxiliary branch, wherein a first end of the auxiliary branch is in communication with the refrigerant circulation loop, and the communication position is located between the outdoor heat exchanger and the electronic expansion valve, and a second end of the auxiliary branch is in communication with the compressor; and the solenoid valve and the capillary tube are arranged on the auxiliary branch. In the high-temperature refrigeration mode, the high-temperature refrigeration and air-conditioning system provided by the present invention can not only reduce the discharge temperature of the compressor, but can also improve the refrigeration capability of the system under high-temperature working conditions.

Description

High temperature refrigeration and air conditioning system and control method This application claims priority to Chinese patent application No. 202410213759.1 filed on February 27, 2024, with the invention name “High-temperature refrigeration and air-conditioning system and control method”. The entire contents of the above Chinese patent application are incorporated into this application by reference. Technical Field

[0001] The present invention relates to the technical field of air-conditioning systems, and in particular provides a high-temperature refrigeration air-conditioning system and a control method. Background Art

[0002] R32 has an ozone depletion potential (ODP) of 0 and a global warming potential (GWP) of 675. It is a refrigerant with acceptable environmental and thermal properties, and is an effective alternative to high-GWP HFC refrigerants such as R410A and R407C. However, higher exhaust temperatures reduce the operating range of R32 compressors, which limits the application of R32 systems in many areas. Lowering the exhaust temperature of R32 compressors and improving the performance of R32 systems under harsh operating conditions are important for promoting the application of R32 and reducing greenhouse gas emissions.

[0003] Lowering the compressor exhaust temperature requires cooling the refrigerant in the compressor's working chamber. Generally speaking, compressor cooling methods can be categorized as external cooling and internal cooling. External cooling involves introducing a medium such as lubricating oil or water to remove heat from the scroll disk. This type of device has a complex compressor structure and requires an external circulation system to cool the medium, resulting in high system costs. Internal cooling generally refers to methods that directly reduce the refrigerant temperature in the working chamber by injecting a refrigerant with a lower specific enthalpy. These methods include suction liquid injection (suction two-phase), intermediate liquid injection, and gas / two-phase injection. Suction liquid injection (suction two-phase) reduces the suction dryness by controlling the opening of the expansion valve, thereby achieving wet compression. This is a commonly used method for internal cooling. However, suction liquid injection (suction two-phase) requires strict control over the suction dryness range to prevent damage to the compressor due to wet compression, especially under harsh operating conditions, where the compressor frequency is generally high. Once wet compression exceeds the compressor's inherent tolerance limit, it poses a significant risk to the smooth and safe operation of the system. Therefore, precise control of the suction dryness is the key to suction liquid injection (suction two-phase) and is also the difficulty of control. Intermediate liquid injection refers to the technology of spraying the subcooled refrigerant liquid at the outlet of the condenser into the intermediate compression chamber of the compressor. This technology requires matching with a dedicated liquid injection compressor. The system structure is relatively complex and the cost is relatively high. Gas injection refers to the technology of spraying saturated or superheated gas refrigerant into the intermediate compression chamber of the compressor. It can be achieved through an intermediate heat exchanger system (also called an economizer system) or a flash tank system. If the dryness of the injected refrigerant is reduced, two-phase injection can be achieved. This technology also needs to be matched with a corresponding air supply compressor, and the system structure is relatively complex.

[0004] Accordingly, the art requires a new air-conditioning system to solve the above problems. Summary of the Invention

[0005] The present invention aims to solve the above-mentioned technical problem, namely, to solve the problem of excessively high compressor exhaust temperature in high-temperature cooling mode in existing air-conditioning systems. To this end, the present invention provides a high-temperature refrigeration air-conditioning system, comprising an indoor heat exchanger, an outdoor heat exchanger, a four-way reversing valve, an electronic expansion valve, and a compressor, wherein the indoor heat exchanger, the outdoor heat exchanger, the four-way reversing valve, the electronic expansion valve, and the compressor form a closed-loop refrigerant circulation circuit; the high-temperature refrigeration air-conditioning system also comprises a solenoid valve, a capillary tube, and an auxiliary branch; the first end of the auxiliary branch is connected to the refrigerant circulation circuit and the connection point is located between the outdoor heat exchanger and the electronic expansion valve, and the second end of the auxiliary branch is connected to the compressor; the solenoid valve and the capillary tube are arranged on the auxiliary branch.

[0006] In a specific embodiment of the above-mentioned high-temperature refrigeration and air-conditioning system, the solenoid valve is close to the first end of the auxiliary branch, and the capillary tube is close to the second end of the auxiliary branch.

[0007] The high-temperature refrigeration and air-conditioning system provided by the present invention has the following beneficial effects: in cooling mode, the compressor discharges high-temperature, high-pressure refrigerant gas, which passes through a four-way reversing valve to the outdoor heat exchanger. There, the heat is released and converted into high-pressure liquid. The discharged high-pressure liquid is throttled in two ways. One way is throttled by an electronic expansion valve and converted into low-pressure wet steam. It then enters the indoor heat exchanger to absorb heat. After absorbing heat, the refrigerant exits the evaporator and becomes superheated gas, which then enters the compressor. This is the main path. The other way is throttled by a solenoid valve through a capillary tube and converted into wet steam. After mixing with the superheated gas in the main path, it enters the compressor, completing a closed working cycle. Because the wet steam and superheated gas mix before entering the compressor, this method reduces the compressor's suction temperature and system pressure ratio, thereby reducing the compressor's discharge temperature by 10 to 15°C.

[0008] The present invention also provides a control method for a high-temperature refrigeration and air-conditioning system, which is applied to the high-temperature refrigeration and air-conditioning system described above. The control method comprises the following steps:

[0009] Get the ambient temperature;

[0010] Determining whether the ambient temperature exceeds a first threshold;

[0011] If yes, execute the high temperature cooling mode, otherwise execute the normal cooling mode.

[0012] In a specific embodiment of the control method of the high-temperature refrigeration and air-conditioning system, the step of "executing the normal cooling mode" includes the following:

[0013] Close the solenoid valve;

[0014] The opening of the electronic expansion valve is adjusted in real time according to the ambient temperature.

[0015] In a specific embodiment of the control method of the high-temperature refrigeration and air-conditioning system, the step of "executing the high-temperature refrigeration mode" includes the following:

[0016] Open the solenoid valve;

[0017] Get the exhaust temperature of the compressor;

[0018] determining whether the exhaust temperature exceeds a second threshold;

[0019] If yes, adjust the opening of the solenoid valve, otherwise the air conditioning system continues to operate;

[0020] Get the outlet superheat of the indoor heat exchanger;

[0021] determining whether the outlet superheat exceeds a third threshold;

[0022] If yes, adjust the opening of the electronic expansion valve, otherwise, the air conditioning system continues to operate.

[0023] In a specific embodiment of the control method of the high-temperature refrigeration and air-conditioning system, the step of "adjusting the opening of the electronic expansion valve in real time" includes the following:

[0024] Get the outlet superheat of the indoor heat exchanger;

[0025] When the outlet superheat exceeds a fourth threshold, the opening of the electronic expansion valve is adjusted.

[0026] In a specific implementation of the control method for the above-mentioned high-temperature refrigeration air-conditioning system, when the outlet superheat degree does not exceed the fourth threshold value, the air-conditioning system continues to operate.

[0027] In a specific embodiment of the control method of the high-temperature refrigeration and air-conditioning system, the step of "obtaining the exhaust temperature of the compressor" includes the following:

[0028] After the solenoid valve is opened, the operating time of the air conditioning system is obtained;

[0029] When the operating time of the air conditioning system exceeds a fifth threshold, the exhaust temperature of the compressor is acquired.

[0030] In a specific implementation of the above-mentioned control method for a high-temperature refrigeration air-conditioning system, when the operating time of the air-conditioning system does not exceed the fifth threshold, the operating time of the air-conditioning system continues to be obtained.

[0031] In a specific implementation of the above-mentioned control method for a high-temperature refrigeration and air-conditioning system, the ambient temperature is the outdoor ambient temperature.

[0032] The beneficial effects of the control method of the high-temperature refrigeration air-conditioning system provided by the present invention are as follows: according to the relationship between the outdoor ambient temperature and the first threshold value, the high-temperature refrigeration air-conditioning can provide two working modes, one is the conventional refrigeration mode, and the other is the high-temperature refrigeration mode; in the high-temperature refrigeration mode, the opening of the solenoid valve and the opening of the electronic expansion valve are adjusted respectively according to the exhaust temperature of the compressor and the outlet superheat of the indoor heat exchanger, so as to better adjust the indoor temperature in a timely and rapid manner, thereby achieving the purpose of lowering the exhaust temperature of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0034] FIG1 is a schematic structural diagram of a high-temperature refrigeration and air-conditioning system provided by the present invention;

[0035] FIG2 is a schematic structural diagram showing the position of the gas-liquid separator based on FIG1;

[0036] FIG3 is a simplified logic diagram of a control method for a high-temperature refrigeration and air-conditioning system provided by the present invention;

[0037] FIG4 is a simplified logic diagram of the high-temperature refrigeration and air-conditioning system provided by the present invention in a conventional refrigeration mode;

[0038] FIG5 is a simplified logic diagram of the high-temperature refrigeration and air-conditioning system provided by the present invention in the high-temperature refrigeration mode;

[0039] FIG6 is an extended logic diagram of step S302 in FIG4 ;

[0040] FIG. 7 is an extended logic diagram of step S304 in FIG. 5 .

[0041] In the figure: 1. Indoor heat exchanger; 2. Outdoor heat exchanger; 3. Four-way reversing valve; 4. Electronic expansion valve; 5. Compressor; 6. Solenoid valve; 7. Capillary tube; 8. Gas-liquid separator. DETAILED DESCRIPTION

[0042] It should be noted that, in the description of the present invention, terms such as "upper," "lower," "left," "right," "inner," and "outer" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are used solely for ease of description and are not intended to indicate or imply that the relevant devices or components must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, ordinal numbers such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted" and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0044] As shown in Figures 1 and 2, the present invention proposes a high-temperature refrigeration and air-conditioning system, which includes an indoor heat exchanger 1, an outdoor heat exchanger 2, a four-way reversing valve 3, an electronic expansion valve 4 and a compressor 5. The indoor heat exchanger 1, the outdoor heat exchanger 2, the four-way reversing valve 3, the electronic expansion valve 4 and the compressor 5 form a closed-loop refrigerant circulation circuit; the high-temperature refrigeration and air-conditioning system also includes a solenoid valve 6, a capillary tube 7 and an auxiliary branch, the first end of the auxiliary branch is connected to the refrigerant circulation circuit and the connection point is located between the outdoor heat exchanger 2 and the electronic expansion valve 4, and the second end of the auxiliary branch is connected to the compressor 5; the solenoid valve 6 and the capillary tube 7 are arranged on the auxiliary branch.

[0045] In this embodiment, the high-temperature refrigeration and air-conditioning system includes an indoor heat exchanger 1, an outdoor heat exchanger 2, a four-way reversing valve 3, an electronic expansion valve 4, a compressor 5, an auxiliary branch, a solenoid valve 6, and a capillary tube 7. The indoor heat exchanger 1, the outdoor heat exchanger 2, the four-way reversing valve 3, the electronic expansion valve 4, and the compressor 5 constitute a conventional refrigerant circulation loop. To reduce the exhaust temperature of the compressor 5, an auxiliary branch, a solenoid valve 6, and a capillary tube 7 are further provided in the system. The auxiliary branch has a first end and a second end. The first end of the auxiliary branch is connected to the refrigerant circulation loop, and the connection point is located between the outdoor heat exchanger 2 and the electronic expansion valve 4. The second end of the auxiliary branch is connected to the compressor 5. The solenoid valve 6 and the capillary tube 7 are both provided on the auxiliary branch.

[0046] The high-temperature refrigeration and air-conditioning system provided by the present invention operates as follows: In cooling mode, compressor 5 discharges high-temperature, high-pressure refrigerant gas, which passes through four-way reversing valve 3 to reach outdoor heat exchanger 2. There, heat is released and the refrigerant becomes high-pressure liquid. The discharged high-pressure liquid is then throttled in two ways. One way is throttled by electronic expansion valve 4, becoming low-pressure wet steam. It then enters indoor heat exchanger 1 to absorb heat. After absorbing heat, the refrigerant exits the evaporator as superheated gas and enters compressor 5. This is the main path. The other way passes through solenoid valve 6 and is throttled by capillary tube 7, becoming wet steam. After mixing with the superheated gas in the main path, it enters compressor 5, completing a closed working cycle. Because the wet steam and superheated gas mix before entering compressor 5, this method reduces the compressor's suction temperature and system pressure ratio, thereby reducing the compressor's discharge temperature by 10-15°C.

[0047] It should be noted that the above technical solution is for a compressor 5 containing a gas-liquid separator 8. If a compressor 5 without a gas-liquid separator 8 is used in the air-conditioning system, a gas-liquid separator 8 needs to be added to the air-conditioning system so that the gas first enters the gas-liquid separator 8 and then enters the compressor 5.

[0048] Further, as shown in FIG1 and FIG2 , the solenoid valve 6 is close to the first end of the auxiliary branch, and the capillary tube 7 is close to the second end of the auxiliary branch.

[0049] In this embodiment, since the first end of the auxiliary branch is the inlet of the auxiliary branch, and the solenoid valve 6 is provided on the auxiliary branch, primarily to open and close the auxiliary branch, placing the solenoid valve 6 closer to the inlet of the auxiliary branch facilitates flow control of the entire auxiliary branch due to the larger pressure differential between the front and rear ends, thereby more easily achieving the goal of reducing the compressor exhaust temperature.

[0050] The present invention also provides a control method for a high-temperature refrigeration and air-conditioning system, which is applied to the high-temperature refrigeration and air-conditioning system described above. As shown in FIG3 , the control method includes the following steps:

[0051] Step S10: obtaining the ambient temperature;

[0052] Step S20: determining whether the ambient temperature exceeds a first threshold;

[0053] Step S30: If yes, execute the high temperature cooling mode; otherwise, execute the normal cooling mode.

[0054] In this embodiment, since the high-temperature refrigeration air-conditioning system has an additional auxiliary branch, a solenoid valve, and a capillary tube compared to existing air-conditioning systems, the high-temperature refrigeration air-conditioning system provided by the present invention includes two operating modes. When the solenoid valve is open, the auxiliary branch is unblocked, and the entire air-conditioning system enters the high-temperature refrigeration mode; when the solenoid valve is closed, the auxiliary branch is blocked, and the entire air-conditioning system enters the conventional refrigeration mode. The high-temperature refrigeration air-conditioning system includes a temperature sensor and a controller. The temperature sensor and the solenoid valve are both electrically connected to the controller. The temperature sensor is located outdoors and is used to measure the outdoor ambient temperature. Once the outdoor ambient temperature exceeds a first threshold, the temperature sensor transmits a signal to the controller, which then controls the solenoid valve to open. When the outdoor ambient temperature does not exceed the first threshold, the solenoid valve is closed.

[0055] In one practical application, the first threshold can be selected between 45 and 50°C. Since temperatures within this range do not occur frequently, the solenoid valve can be in a normally closed state. It should also be noted that the first threshold can also be selected within other ranges, and those skilled in the art can set the first threshold based on actual operating conditions.

[0056] Further, as shown in FIG4 , the step of “executing the normal cooling mode” includes the following:

[0057] Step S301, closing the solenoid valve;

[0058] Step S302: Adjust the opening of the electronic expansion valve in real time according to the ambient temperature.

[0059] In this embodiment, in conventional cooling mode, due to changes in ambient temperature, the amount of refrigerant in the refrigerant circulation loop must be adjusted promptly to maintain a constant indoor temperature. Therefore, real-time monitoring of the ambient temperature is necessary to adjust the opening of the electronic expansion valve in real time. This control method for conventional cooling mode in an air conditioning system not only saves a significant amount of energy but also improves the user experience.

[0060] Further, as shown in FIG5 , the step of “executing the high temperature cooling mode” includes the following:

[0061] Step S303: Open the solenoid valve;

[0062] Step S304: obtaining the exhaust temperature of the compressor;

[0063] Step S305: determining whether the exhaust temperature exceeds a second threshold;

[0064] Step S306: If yes, adjust the opening of the solenoid valve; otherwise, the air conditioning system continues to operate;

[0065] Step S307: Obtain the outlet superheat of the indoor heat exchanger;

[0066] Step S308: determining whether the outlet superheat exceeds a third threshold;

[0067] Step S309: If yes, adjust the opening of the electronic expansion valve; otherwise, the air conditioning system continues to operate.

[0068] In this embodiment, because the air conditioning system needs to enter high-temperature cooling mode, the solenoid valve is opened and the opening of the electronic expansion valve is adjusted sequentially according to actual conditions. After the solenoid valve is opened, the auxiliary branch circuit comes into play, and the compressor exhaust temperature does not immediately decrease. Higher ambient temperatures increase the time required for the compressor exhaust temperature to fall within a safe range. To maintain a constant indoor temperature within a certain range, the need to adjust the solenoid valve opening is determined based on the relationship between the compressor exhaust temperature and a second threshold. The greater the value by which the exhaust temperature exceeds the second threshold, the greater the required solenoid valve opening.

[0069] In some cases, if the indoor temperature continues to rise, the opening of the electronic expansion valve needs to be adjusted to quickly reduce the indoor temperature. The opening of the electronic expansion valve is adjusted based on the comparison of the outlet superheat of the indoor heat exchanger with a third threshold. When the outlet superheat exceeds the third threshold, the opening of the electronic expansion valve needs to be further increased, that is, the amount of refrigerant in the refrigerant circulation loop is increased and the flow rate is faster.

[0070] It should be noted that the second threshold value can be selected between 100 and 110° C., and the third threshold value can be selected between 4 and 6° C. It should be noted that those skilled in the art can set the second and third threshold values ​​to other values ​​according to actual working conditions.

[0071] Furthermore, as shown in FIG6 , the step of “adjusting the opening of the electronic expansion valve in real time” includes the following:

[0072] Step S3021, obtaining the outlet superheat of the indoor heat exchanger;

[0073] Step S3022: When the outlet superheat exceeds a fourth threshold, adjust the opening of the electronic expansion valve.

[0074] In this embodiment, in conventional cooling mode, the outlet superheat of the indoor heat exchanger is detected and used as a basis to adjust the opening of the electronic expansion valve. This adjustment method can keep the indoor temperature within a constant range, and even if there are large temperature fluctuations, it will quickly return to the constant range. This control method not only significantly reduces the power consumption of the air conditioning system, but also improves the customer experience.

[0075] Further, as shown in FIG6 , in step S3033 , when the outlet superheat degree does not exceed the fourth threshold, the air conditioning system continues to operate.

[0076] In this embodiment, when the outlet superheat of the indoor heat exchanger does not exceed the fourth threshold, it proves that the indoor temperature is within a constant range. Therefore, there is no need to interfere too much with the air-conditioning system, and it is only necessary to maintain the normal operation of the air-conditioning system.

[0077] It should be noted that those skilled in the art can set the fourth threshold value according to the actual working conditions. This setting time can be selected when the air conditioner leaves the factory or when the air conditioner is installed.

[0078] Further, as shown in FIG7 , the step of “obtaining the exhaust temperature of the compressor” includes the following:

[0079] Step S3041: After the solenoid valve is opened, obtain the operating time of the air conditioning system;

[0080] Step S3042: When the operating time of the air conditioning system exceeds the fifth threshold, the exhaust temperature of the compressor is obtained. When the operating time of the air conditioning system does not exceed the fifth threshold, the operating time of the air conditioning system is continued to be obtained.

[0081] In this embodiment, when the outdoor ambient temperature is high, although the solenoid valve can be opened as soon as possible, if the compressor performs a complete operation in the refrigerant circulation loop, that is, if the air-conditioning system does not run for a stable period of time, it cannot be guaranteed that the auxiliary branch will play a cooling role, and the exhaust temperature of the compressor detected is likely to be the exhaust temperature under the conventional refrigeration mode. At this time, if the opening of the solenoid valve is adjusted rashly, or even the opening of the electronic expansion valve is adjusted, it is not the best control method.

[0082] In high-temperature cooling mode, after the solenoid valve is opened, the air-conditioning system can be operated for a period of time before the exhaust temperature of the compressor can be monitored. At this time, according to the above control method, more accurate control can be achieved, and ultimately the customer experience is improved.

[0083] To further improve the accuracy and automation of the control method, new steps can be added to the control method. For example, after the solenoid valve opens, the operating time of the air conditioning system can be monitored. Once the solenoid valve opens, a timer can be started. When the timer exceeds a set threshold, the compressor exhaust temperature can be checked. If the timer does not exceed the set threshold, the compressor exhaust temperature does not need to be monitored.

[0084] Furthermore, the ambient temperature is the outdoor ambient temperature.

[0085] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A high temperature refrigeration and air conditioning system, characterized in that: The high-temperature refrigeration and air-conditioning system comprises an indoor heat exchanger (1), an outdoor heat exchanger (2), a four-way reversing valve (3), an electronic expansion valve (4) and a compressor (5), wherein the indoor heat exchanger (1), the outdoor heat exchanger (2), the four-way reversing valve (3), the electronic expansion valve (4) and the compressor (5) form a closed-loop refrigerant circulation circuit; the high-temperature refrigeration and air-conditioning system further comprises a solenoid valve (6), a capillary tube (7) and an auxiliary branch, wherein a first end of the auxiliary branch is connected to the refrigerant circulation circuit and a connection point is located between the outdoor heat exchanger (2) and the electronic expansion valve (4), and a second end of the auxiliary branch is connected to the compressor (5); the solenoid valve (6) and the capillary tube (7) are arranged on the auxiliary branch.

2. The high-temperature refrigeration and air-conditioning system according to claim 1, characterized in that: The solenoid valve (6) is close to the first end of the auxiliary branch, and the capillary tube (7) is close to the second end of the auxiliary branch.

3. A control method for a high-temperature refrigeration and air-conditioning system, applied to the high-temperature refrigeration and air-conditioning system according to claim 1 or 2, characterized in that: The control method comprises the following steps: Get the ambient temperature; Determining whether the ambient temperature exceeds a first threshold; If yes, execute the high temperature cooling mode, otherwise execute the normal cooling mode.

4. The control method of the high temperature refrigeration and air conditioning system according to claim 3, characterized in that: The steps for "Performing Normal Cooling Mode" include the following: Close the solenoid valve; The opening of the electronic expansion valve is adjusted in real time according to the ambient temperature.

5. The control method of a high temperature refrigeration and air conditioning system according to claim 4, characterized in that: The steps for "Executing High Temperature Cooling Mode" include the following: Open the solenoid valve; Get the exhaust temperature of the compressor; determining whether the exhaust temperature exceeds a second threshold; If yes, adjust the opening of the solenoid valve, otherwise the air conditioning system continues to operate; Get the outlet superheat of the indoor heat exchanger; determining whether the outlet superheat exceeds a third threshold; If yes, adjust the opening of the electronic expansion valve, otherwise, the air conditioning system continues to operate.

6. The control method of the high temperature refrigeration and air conditioning system according to claim 5, characterized in that: The steps for "adjusting the opening of the electronic expansion valve in real time" include the following: Get the outlet superheat of the indoor heat exchanger; When the outlet superheat exceeds a fourth threshold, the opening of the electronic expansion valve is adjusted.

7. The control method of a high temperature refrigeration and air conditioning system according to claim 6, characterized in that: When the outlet superheat degree does not exceed the fourth threshold, the air conditioning system continues to operate.

8. The control method of a high temperature refrigeration and air conditioning system according to any one of claims 3 to 5, characterized in that: The steps for "obtaining the compressor's discharge temperature" include the following: After the solenoid valve is opened, the operating time of the air conditioning system is obtained; When the operating time of the air conditioning system exceeds a fifth threshold, the exhaust temperature of the compressor is acquired.

9. The control method of a high temperature refrigeration and air conditioning system according to claim 8, characterized in that: When the operating time of the air-conditioning system does not exceed the fifth threshold, the operating time of the air-conditioning system continues to be obtained.

10. The control method of a high temperature refrigeration and air conditioning system according to any one of claims 3 to 5, characterized in that: The ambient temperature is the outdoor ambient temperature.

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