Control method, control device, dual-cycle refrigeration system and storage medium

Abstract

The application provides a control method, a control device, a double-circulation refrigeration system and a computer readable storage medium, and can improve the system energy efficiency in a mixed refrigeration mode. The control method comprises the following steps: obtaining an operating parameter of a double-circulation refrigeration system; determining the superheat degree of a compressor according to the operating parameter of the double-circulation refrigeration system, wherein the superheat degree is the suction superheat degree or the discharge superheat degree of the compressor; and controlling a throttling device and a fluorine pump according to the superheat degree of the compressor in the mixed refrigeration mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration systems, and particularly relates to a control method, a control device, a double-cycle refrigeration system and a computer readable storage medium. BACKGROUND

[0002] At present, based on the characteristics of the whole year refrigeration of a data center, the traditional whole year compressor refrigeration cannot meet the requirements of customers on the PUE (Power Usage Effectiveness, energy use efficiency) of the data center. Therefore, when the ambient temperature is lower than the temperature of the machine room, a solution of using a natural cold source to perform refrigeration has been continuously promoted in the industry, especially a way of connecting a fluorine pump in series with an original compressor refrigeration cycle system as a natural cooling mode, that is, a double-cycle refrigeration system of a compressor fluorine pump is used to refrigerate the machine room.

[0003] Among them, the refrigeration modes of the double-cycle refrigeration system usually include a compressor refrigeration mode, a mixed refrigeration mode and a fluorine pump refrigeration mode. At present, the refrigeration mode is mainly determined according to the outdoor ambient temperature. For example, in summer or other cases of high outdoor temperature, the compressor refrigeration mode is mainly used; in winter or other cases of low outdoor temperature, the fluorine pump refrigeration mode is mainly used; in spring, autumn and other cases of relatively moderate outdoor temperature, the mixed refrigeration mode is mainly used.

[0004] In the compressor refrigeration mode and the mixed refrigeration mode, the opening degree of the throttling device is controlled according to the superheat degree of the compressor. In the fluorine pump refrigeration mode, the throttling device is kept in a fully open state.

[0005] How to further improve the system energy efficiency is the direction that the person skilled in the art has been striving for. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a control method, a control device, a double-cycle refrigeration system and a computer readable storage medium, so as to improve the system energy efficiency in the mixed refrigeration mode.

[0007] To this end, the present application provides a control method for a double-cycle refrigeration system, and the control method comprises the following steps.

[0008] Obtaining an operating parameter of the double-cycle refrigeration system;

[0009] Determining a superheat degree of a compressor according to the operating parameter of the double-cycle refrigeration system, wherein the superheat degree is a suction superheat degree or a discharge superheat degree of the compressor;

[0010] In the mixed refrigeration mode, the throttling device and the fluorine pump are controlled according to the superheat degree of the compressor.

[0011] The control method provided in this application controls the refrigerant pump and the throttling device based on the superheat of the compressor, rather than simply controlling the throttling device. This allows the refrigerant pump and the throttling device to work together to control the superheat of the compressor. This helps to avoid the refrigerant pump excessively increasing the refrigerant pressure, which would cause the throttling device to excessively reduce the pressure to ensure that the system has a suitable high and low pressure difference, resulting in unnecessary pump power loss. This is beneficial to improving the system energy efficiency in the hybrid refrigeration mode.

[0012] Based on the above technical solution, the following improvements can be made to this application.

[0013] In one exemplary embodiment, the throttling device and refrigerant pump controlled according to the superheat of the compressor include:

[0014] Based on the fact that the superheat of the compressor is greater than the preset target superheat and the difference is greater than the first threshold, where the first threshold is >0℃, the opening of the throttling device is adjusted according to the preset target superheat so that the superheat of the compressor approaches the preset target superheat.

[0015] Based on the fact that the opening degree of the throttling device reaches the set maximum opening degree in the mixed refrigeration mode and the superheat degree of the compressor is still greater than the preset target superheat degree and the difference is greater than the first threshold, the throttling device is controlled to maintain the current opening degree, and the speed of the refrigerant pump is adjusted according to the preset target superheat degree so that the superheat degree of the compressor approaches the preset target superheat degree.

[0016] In one exemplary embodiment, the throttling device and refrigerant pump controlled according to the superheat of the compressor include:

[0017] Based on the fact that the superheat of the compressor is less than the preset target superheat and the difference is less than the second threshold, where the second threshold is <0℃, the speed of the refrigerant pump is adjusted according to the preset target superheat to make the superheat of the compressor approach the preset target superheat.

[0018] Based on the fact that the speed of the refrigerant pump is reduced to the set minimum speed and the superheat of the compressor is still less than the preset target superheat and the difference is less than the second threshold, the refrigerant pump is controlled to maintain the current speed, and the opening of the throttling device is adjusted according to the preset target superheat so that the superheat of the compressor approaches the preset target superheat.

[0019] In an exemplary embodiment, the throttling device and refrigerant pump controlled according to the superheat of the compressor further include:

[0020] Based on the fact that the speed of the refrigerant pump is the set minimum speed, the opening degree of the throttling device is lower than the first set opening degree, and the superheat of the compressor is still less than the preset target superheat degree and the difference is less than the second threshold, the dual-cycle refrigeration system is controlled to switch to compressor refrigeration mode, and the first set opening degree is <100%.

[0021] In one exemplary embodiment, the control method further includes:

[0022] In compressor refrigeration mode, the system determines whether to switch to hybrid refrigeration mode based on the operating parameters of the dual-cycle refrigeration system.

[0023] In one exemplary embodiment, the operating parameters of the dual-cycle refrigeration system include: the operating parameters of the throttling device and the operating parameters of the compressor;

[0024] The step of determining whether to switch to hybrid cooling mode based on the operating parameters of the dual-cycle refrigeration system includes:

[0025] Determine whether to switch to hybrid refrigeration mode based on the operating parameters of the throttling device and the operating parameters of the compressor.

[0026] In one exemplary embodiment, the operating parameters of the throttling device include: the opening degree of the throttling device, and the operating parameters of the compressor include: the superheat degree of the compressor;

[0027] The step of determining whether to switch to hybrid refrigeration mode based on the operating parameters of the throttling device and the operating parameters of the compressor includes:

[0028] Based on the fact that the opening degree of the throttling device is greater than the second set opening degree, and the superheat degree of the compressor is greater than the set superheat degree, it is determined that the dual-cycle refrigeration system switches to the hybrid refrigeration mode, and the second set opening degree is less than 100%.

[0029] In one exemplary embodiment, the control method further includes:

[0030] Based on the fact that the dual-cycle refrigeration system switches from compressor mode to hybrid refrigeration mode and then switches back to compressor refrigeration mode within a preset time, the set superheat is increased.

[0031] In one exemplary embodiment, the control method further includes:

[0032] Under compressor refrigeration mode, the conditions for switching to refrigerant pump refrigeration mode are met;

[0033] Control the compressor to operate at a lower frequency, control the refrigerant pump to start softly, and control the opening of the throttling device according to the superheat of the compressor;

[0034] Based on the compressor frequency decreasing to the first set frequency and the refrigerant pump frequency increasing to the second set frequency, the compressor is turned off, and the throttling device is opened to the fully open state, so that the dual-cycle refrigeration system switches to the refrigerant pump refrigeration mode.

[0035] In one exemplary embodiment, the control method further includes:

[0036] In refrigerant pump refrigeration mode, the conditions for switching compressor refrigeration mode are met;

[0037] The compressor is controlled to start softly, and the refrigerant pump is controlled to operate at a reduced frequency. The opening of the throttling device is reduced to the initial opening of the compressor in refrigeration mode. Then, the opening of the throttling device is controlled according to the superheat of the compressor.

[0038] Based on the compressor frequency increasing to the third set frequency and the refrigerant pump frequency decreasing to the fourth set frequency, the refrigerant pump is turned off, and the dual-cycle refrigeration system is switched to compressor refrigeration mode.

[0039] In one exemplary embodiment, the control method further includes:

[0040] During the process of switching from compressor refrigeration mode to refrigerant pump refrigeration mode, the speed of the outdoor fan is controlled according to the compressor's discharge pressure;

[0041] During the process of switching from refrigerant pump refrigeration mode to compressor refrigeration mode, the speed of the outdoor fan is controlled according to the compressor's discharge pressure.

[0042] This application also provides a control device, including a processor and a memory storing a computer program, wherein the processor executes the computer program to implement the steps of the control method as described in any of the above embodiments.

[0043] This application also provides a dual-cycle refrigeration system, including the control device described in the above embodiments.

[0044] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the control method as described in any of the above embodiments. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of a dual-cycle refrigeration system provided in some embodiments of this application;

[0046] Figure 2 A flowchart illustrating the control method provided in some embodiments of this application;

[0047] Figure 3 A schematic flowchart illustrating a control method provided in one embodiment of this application;

[0048] Figure 4 A schematic flowchart illustrating a control method provided in one embodiment of this application;

[0049] Figure 5 A schematic flowchart illustrating a control method provided in one embodiment of this application;

[0050] Figure 6 This is a flowchart illustrating a control method provided in one embodiment of this application.

[0051] Figure 1 The list of components represented by each number is as follows:

[0052] 1. Condenser, 2. Outdoor fan, 3. Liquid receiver, 4. Refrigerant pump, 5. Second check valve, 6. Throttling device, 7. Evaporator, 8. Indoor fan, 9. First check valve, 10. Compressor, 11. Compressor bypass path, 12. Refrigerant pump bypass path. Detailed Implementation

[0053] The principles and features of this application are described below with reference to the accompanying drawings. The examples given are only for explaining this application and are not intended to limit the scope of this application.

[0054] This application provides a control method for a dual-cycle refrigeration system.

[0055] like Figure 1 As shown, the dual-cycle refrigeration system may include: a compressor 10, a condenser 1, a liquid receiver 3, a refrigerant pump 4, a throttling device 6, and an evaporator 7 connected by pipelines to form a loop; an outdoor fan 2 corresponding to the condenser 1 and an indoor fan 8 corresponding to the evaporator 7; a compressor bypass flow path 11 connected in parallel with the compressor 10 and a first check valve 9 located in the compressor bypass flow path 11; a refrigerant pump bypass flow path 12 connected in parallel with the refrigerant pump 4 and a second check valve 5 located in the refrigerant pump bypass flow path 12. The first check valve 9 is configured to unidirectionally open in the direction from the outlet of the evaporator 7 to the inlet of the condenser 1. The second check valve 5 is configured to unidirectionally open in the direction from the outlet of the condenser 1 to the inlet of the evaporator 7. A liquid receiver 3 may also be installed between the outlet of the condenser 1 and the refrigerant pump 4. The evaporator 7 and the indoor fan 8 are located on the indoor side, and the condenser 1 and the outdoor fan 2 are located on the outdoor side. The throttling device 6 may be, but is not limited to, an electronic expansion valve.

[0056] The dual-cycle refrigeration system can be set to have the following three refrigeration modes: compressor refrigeration mode, hybrid refrigeration mode, and refrigerant pump refrigeration mode. The working principle of each refrigeration mode is as follows:

[0057] Compressor refrigeration mode: First one-way valve 9 is closed, and second one-way valve 5 is open. The refrigerant flows sequentially through compressor 10, condenser 1, receiver 3, refrigerant pump bypass path 12, throttling device 6, and evaporator 7, forming the first circulation loop. In this refrigeration mode, refrigerant pump 4 stops, and compressor 10 starts, providing power for the system's refrigeration operation.

[0058] Hybrid refrigeration mode: The first one-way valve 9 is closed, and the second one-way valve 5 is closed. The refrigerant flows sequentially through the compressor 10, condenser 1, receiver 3, refrigerant pump 4, throttling device 6, and evaporator 7, forming a second circulation loop. In this refrigeration mode, both the refrigerant pump 4 and the compressor 10 are started, partially utilizing outdoor natural cold sources. The refrigerant pump 4 can compensate for the circulation dynamics of the refrigerant in the system, reducing the pressure loss of the refrigerant during circulation, allowing the compressor 10 to operate under optimal conditions, reducing the energy consumption of the compressor 10, improving refrigeration efficiency, and achieving a certain energy-saving effect.

[0059] Refrigerant pump refrigeration mode: First one-way valve 9 is open, second one-way valve 5 is closed. For example... Figure 1 As shown, the refrigerant flows sequentially through the compressor bypass path 11, condenser 1, receiver 3, refrigerant pump 4, throttling device 6, and evaporator 7, forming a third circulation loop. In this cooling mode, refrigerant pump 4 starts while compressor 10 stops, making full use of the outdoor natural cold source. Refrigerant pump 4 replaces compressor 10 to provide power for the system circulation. Since the power of refrigerant pump 4 is much smaller than that of compressor 10, the power consumption of the computer room air conditioner can be significantly reduced, resulting in significant energy-saving effects.

[0060] In related technologies, in the hybrid refrigeration mode, a throttling device 6 is often used to control the superheat of the compressor 10 to ensure the energy efficiency of the compressor 10. However, since the throttling device 6 and the refrigerant pump 4 have opposite functions, the pump power may be wasted, resulting in a decrease in system energy efficiency.

[0061] In some exemplary embodiments, such as Figure 2 As shown, the control methods include:

[0062] Step S202: Obtain the operating parameters of the dual-cycle refrigeration system;

[0063] Step S204: Determine the superheat of the compressor based on the operating parameters of the dual-cycle refrigeration system;

[0064] Step S206: In the mixed refrigeration mode, the throttling device and refrigerant pump are controlled according to the superheat of the compressor.

[0065] Wherein, the superheat refers to either the suction superheat or the discharge superheat of the compressor 10. Since the trends of suction superheat and discharge superheat are generally the same—that is, as suction superheat increases, discharge superheat usually also increases; and as suction superheat decreases, discharge superheat usually also decreases—in this embodiment, the superheat of the compressor 10 can be either the suction superheat or the discharge superheat of the compressor 10.

[0066] Research has found that the reason why the opposing effects of the throttling device 6 and the refrigerant pump 4 may lead to unnecessary pump power loss is that, since the refrigerant pump 4 and the compressor 10 are connected in series in a refrigeration system, the refrigeration mechanism of the hybrid refrigeration mode is still a reverse Carnot cycle. The main function of the refrigerant pump 4 is to offset the adverse effects of the liquid line pressure drop on the refrigeration system's energy efficiency by reducing the high-low pressure difference to improve the system's operating energy efficiency. However, if the operation of the refrigerant pump 4 not only offsets the adverse effects of the liquid line pressure drop on the refrigeration system's energy efficiency but also additionally increases the refrigerant pressure, i.e., excessively reduces the high-low pressure difference of the system, then the throttling device 6 needs to reduce the additional pressure increased by the refrigerant pump 4 to ensure that the system has a suitable high-low pressure difference, so as to ensure that the compressor 10 has a suitable suction superheat, and thus has higher energy efficiency. This leads to unnecessary pump power loss, causing a decrease in system energy efficiency. However, in related technologies, in the hybrid refrigeration mode, simply controlling the superheat of the compressor 10 through the throttling device 6 is difficult to avoid the occurrence of unnecessary pump power loss, therefore the system energy efficiency of the hybrid mode needs further improvement.

[0067] The control method provided in this application embodiment controls the refrigerant pump 4 and the throttling device 6 based on the superheat of the compressor 10, rather than simply controlling the throttling device 6. This allows the refrigerant pump 4 and the throttling device 6 to work together to control the superheat of the compressor 10. This helps to avoid the refrigerant pump 4 excessively increasing the refrigerant pressure, which would cause the throttling device 6 to excessively reduce the pressure to ensure that the system has a suitable high and low pressure difference, resulting in unnecessary pump power loss. This is beneficial to improving the system energy efficiency in the hybrid refrigeration mode.

[0068] The specific control method for the fluorine pump 4 and the throttling device 6 is not limited; for example, it can be a linear control method or a PID (Proportional Integral Derivative) control method.

[0069] As mentioned above, in this embodiment, the superheat of compressor 10 can be either the suction superheat or the discharge superheat of compressor 10. However, it is understood that the ideal range of suction superheat (e.g., 5°C to 10°C) is usually different from the ideal range of discharge superheat (e.g., 20°C to 40°C). Therefore, in the control method of this embodiment, some preset parameters when the superheat is suction superheat (such as the preset target superheat, first threshold, second threshold, maximum opening in mixed refrigeration mode, first set opening, second set opening, set superheat, and increase value of set superheat, etc., but not limited to these parameters) can be different from some preset parameters when the superheat is discharge superheat.

[0070] The following explanation uses the superheat of compressor 10 as the suction superheat as an example.

[0071] In some exemplary embodiments, the throttling device 6 and the refrigerant pump 4 are controlled according to the superheat of the compressor 10, including:

[0072] Based on the fact that the superheat of compressor 10 is greater than the preset target superheat and the difference is greater than the first threshold, the opening of throttling device 6 is adjusted according to the preset target superheat so that the superheat of compressor 10 approaches the preset target superheat.

[0073] Based on the fact that the opening degree of the throttling device 6 reaches the maximum opening degree set in the mixed refrigeration mode and the superheat of the compressor 10 is still greater than the preset target superheat and the difference is greater than the first threshold, the throttling device 6 is controlled to maintain the current opening degree, and the speed of the refrigerant pump 4 is adjusted according to the preset target superheat so that the superheat of the compressor 10 approaches the preset target superheat.

[0074] Wherein, the difference = superheat of compressor 10 - preset target superheat > 0℃, first threshold > 0℃. The size of the first threshold can be reasonably set as needed, and can be within the range of 3℃ to 8℃, such as 3℃, 4℃, 5℃, 6℃, 7℃, 8℃, etc. The maximum opening degree in the mixed refrigeration mode can be set to 100%, that is, the throttling device 6 reaches the fully open state. The preset target superheat is the superheat at which the compressor 10 has relatively ideal energy efficiency, that is: when the superheat of compressor 10 is the preset target superheat, the energy efficiency of compressor 10 is high. Based on the fact that the superheat of compressor 10 is the suction superheat, the preset target superheat can be within the range of 5℃ to 10℃.

[0075] When the suction superheat of compressor 10 exceeds the preset target superheat and the difference is greater than the first threshold, it indicates that the suction superheat of compressor 10 is significantly higher than the preset target superheat, resulting in low system energy efficiency. In this case, the suction superheat of compressor 10 can be reduced by increasing the opening of the throttling device 6, or by increasing the speed of the refrigerant pump 4. However, increasing the speed of the refrigerant pump 4 will increase its energy consumption. Therefore, increasing the opening of the throttling device 6 is preferred to reduce the suction superheat of compressor 10, bringing it closer to the preset target superheat, thereby improving the energy efficiency of compressor 10 and the overall system energy efficiency.

[0076] When the opening of the throttling device 6 has been increased to the maximum set opening in the mixed refrigeration mode (e.g., fully open), the suction superheat of the compressor 10 is still significantly higher than the preset target superheat. Therefore, the opening of the throttling device 6 cannot be increased further. Instead, the opening of the throttling device 6 remains unchanged. By increasing the speed of the refrigerant pump 4, the suction superheat of the compressor 10 is reduced, allowing it to approach the preset target superheat, thereby improving the energy efficiency of the compressor 10. Since the energy efficiency of the compressor 10 contributes far more to the overall system energy efficiency than that of the refrigerant pump 4, although the increased speed of the refrigerant pump 4 leads to increased power consumption, the overall system energy efficiency is improved due to the increased energy efficiency of the compressor 10.

[0077] In some exemplary embodiments, the throttling device 6 and the refrigerant pump 4 are controlled according to the superheat of the compressor 10, including:

[0078] Based on the fact that the superheat of compressor 10 is less than the preset target superheat and the difference is less than the second threshold, the speed of refrigerant pump 4 is adjusted according to the preset target superheat so that the superheat of compressor 10 approaches the preset target superheat.

[0079] Based on the fact that the speed of the refrigerant pump 4 is reduced to the set minimum speed and the superheat of the compressor 10 is still less than the preset target superheat and the difference is less than the second threshold, the refrigerant pump 4 is controlled to maintain the current speed, and the opening of the throttling device 6 is adjusted according to the preset target superheat so that the superheat of the compressor 10 approaches the preset target superheat.

[0080] Wherein, the difference = superheat of compressor 10 - preset target superheat < 0℃, second threshold < 0℃. The size of the second threshold can be reasonably set as needed, and can be in the range of -8℃ to -3℃, such as -8℃, -7℃, -6℃, -5℃, -4℃, -4℃, etc.

[0081] When the suction superheat of compressor 10 is less than the preset target superheat and the difference is less than the second threshold, it indicates that the suction superheat of compressor 10 is significantly lower than the preset target superheat. In this case, the suction superheat of compressor 10 can be increased by reducing the opening of the throttling device 6, or by reducing the speed of the refrigerant pump 4. However, reducing the speed of the refrigerant pump 4 will reduce its energy consumption, thereby improving system energy efficiency. Therefore, it is preferable to prioritize increasing the suction superheat of compressor 10 by reducing the speed of the refrigerant pump 4, so that the suction superheat of compressor 10 can approach the preset target superheat, thereby improving the energy efficiency of compressor 10 and the system energy efficiency.

[0082] When the speed of the refrigerant pump 4 has been reduced to the set minimum speed, the suction superheat of the compressor 10 is still significantly lower than the preset target superheat. At this time, the speed of the refrigerant pump 4 cannot be reduced further. Therefore, the speed of the refrigerant pump 4 remains unchanged. The suction superheat of the compressor 10 is increased by reducing the opening of the throttling device 6, so that the suction superheat of the compressor 10 can approach the preset target superheat, thereby improving the energy efficiency of the compressor 10.

[0083] In some exemplary embodiments, the throttling device 6 and the refrigerant pump 4, based on the superheat control of the compressor 10, further include:

[0084] Based on the fact that the speed of the refrigerant pump 4 is the set minimum speed, the opening degree of the throttling device 6 is lower than the first set opening degree, and the superheat of the compressor 10 is still less than the preset target superheat and the difference is less than the second threshold, the dual-cycle refrigeration system is controlled to switch to compressor refrigeration mode, and the first set opening degree is <100%.

[0085] The first set opening can be in the range of 50% to 70%, such as 50%, 55%, 60%, 65%, 70%, etc.

[0086] When the refrigerant pump 4 operates at the set minimum speed, the opening of the throttling device 6 is lower than the first set opening, and the superheat of the compressor 10 is still significantly lower than the preset target superheat, it indicates that the refrigerant circulation volume in the system is insufficient, and the system's cooling capacity is inadequate. In this case, the refrigerant circulation volume can be increased by increasing the opening of the throttling device 6. However, the operation of the refrigerant pump 4 actually increases system energy consumption and reduces system energy efficiency. Therefore, the control system switches from the hybrid cooling mode to the compressor cooling mode at this time.

[0087] In one embodiment, such as Figure 3 As shown, the control method includes the following steps:

[0088] Step S302: System operation;

[0089] Step S304: Determine whether the system is in hybrid cooling mode. If yes, proceed to step S306; otherwise, return to step S302.

[0090] Step S306: Obtain the current operating parameters of the system;

[0091] Step S308: Determine whether the following conditions are met: the refrigerant pump speed is at the set minimum speed, the opening degree of the throttling device 6 is lower than the first set opening degree, and the suction superheat of the compressor is less than the preset target superheat and the difference is less than the second threshold. If yes, proceed to step S310; otherwise, return to step S306.

[0092] Step S310: The control system enters the compressor refrigeration mode.

[0093] In step S308, the refrigerant pump speed is at the set minimum speed, which can also be replaced by: the refrigerant pump speed is lower than the set speed threshold. The set speed threshold can be greater than or equal to the set minimum speed.

[0094] In some exemplary embodiments, the control method further includes:

[0095] In compressor refrigeration mode, the system determines whether to switch to hybrid refrigeration mode based on the operating parameters of the dual-cycle refrigeration system.

[0096] As mentioned earlier, since the refrigerant pump 4 and compressor 10 are connected in series in a refrigeration system, the refrigeration mechanism of the hybrid refrigeration mode is still a reverse Carnot cycle. The main function of the refrigerant pump 4 is to offset the adverse effects of liquid line pressure drop on the refrigeration system's energy efficiency, thereby improving the system's operating efficiency by reducing the high-low pressure difference. However, different installation scenarios (such as refrigerant pipe length and height difference between indoor and outdoor units) will cause different liquid line pressure drops, which will in turn cause changes in the operating range of the hybrid refrigeration mode. Related technologies simply define the operating range of the hybrid refrigeration mode based on the outdoor ambient temperature, without considering the impact of the installation scenario on the operating range of the hybrid refrigeration mode, and therefore may not necessarily improve the system's operating efficiency.

[0097] The control method provided in this application, in compressor cooling mode, determines whether to switch to hybrid cooling mode based on the operating parameters of the dual-cycle cooling system, rather than based on the outdoor ambient temperature. Compared to outdoor ambient temperature, the operating parameters of the dual-cycle cooling system better reflect system energy efficiency; therefore, determining whether to switch to hybrid cooling mode based on the operating parameters of the dual-cycle cooling system is beneficial for further improving system energy efficiency.

[0098] Furthermore, the operating parameters of the dual-cycle refrigeration system are affected by the installation scenario (such as refrigerant pipe length, height difference between indoor and outdoor units, etc.). In other words, the operating parameters of the dual-cycle refrigeration system are related to the installation scenario; the operating parameters themselves already include the influence of the installation scenario. Therefore, there is no need to separately consider the impact of the installation scenario on the operating range of the hybrid refrigeration mode. Thus, the control method provided in this application embodiment can be applied to different installation scenarios, and the determined operating range of the hybrid refrigeration mode is beneficial for effectively improving the system's operating energy efficiency.

[0099] This control method is independent of the control method for improving energy efficiency through hybrid cooling mode described in the previous embodiments, and each can be implemented independently.

[0100] In some exemplary embodiments, the operating parameters of the dual-cycle refrigeration system include: the operating parameters of the throttling device 6 and the operating parameters of the compressor 10.

[0101] Determine whether to switch to hybrid cooling mode based on the operating parameters of the dual-cycle refrigeration system, including:

[0102] Determine whether to switch to hybrid refrigeration mode based on the operating parameters of the throttling device 6 and the compressor 10.

[0103] Since the power of compressor 10 is much higher than that of refrigerant pump 4, improving system energy efficiency is mainly achieved by increasing the energy efficiency of compressor 10. The operating parameters of compressor 10 reflect its energy efficiency, and the operating parameters of throttling device 6 affect these parameters, thus impacting its energy efficiency. Therefore, determining whether to switch from compressor-based refrigeration mode to refrigerant pump-based refrigeration mode based on the operating parameters of throttling device 6 and compressor 10 is more reasonable and reliable.

[0104] In some exemplary embodiments, the operating parameters of the throttling device 6 include the opening degree of the throttling device 6, and the operating parameters of the compressor 10 include the superheat degree of the compressor 10.

[0105] Determine whether to switch to hybrid refrigeration mode based on the operating parameters of the throttling device 6 and the compressor 10, including:

[0106] Based on the fact that the opening degree of the throttling device 6 is greater than the second set opening degree, and the superheat of the compressor 10 is greater than the set superheat, it is determined that the dual-cycle refrigeration system switches to the hybrid refrigeration mode.

[0107] Otherwise, the dual-cycle refrigeration system is determined to continue operating in hybrid refrigeration mode.

[0108] Wherein, the second set opening degree is less than 100%, and the second set opening degree can be in the range of, but is not limited to, 70% to 90%, such as 70%, 75%, 80%, 85%, 90%, 95%, etc. The second set opening degree can be greater than the aforementioned first set opening degree. The set superheat degree is greater than the preset target superheat degree in the aforementioned embodiment. For example, if the preset target superheat degree can be 5°C, the set superheat degree here can be 10°C.

[0109] Understandably, the suction superheat of compressor 10 reflects its energy efficiency. A high suction superheat indicates low energy efficiency, while a low suction superheat suggests insufficient refrigerant circulation, potentially affecting the system's cooling capacity. The suction superheat of compressor 10 can be adjusted by regulating the opening of the throttling device 6. Increasing the opening of the throttling device 6 reduces the suction superheat, while decreasing it increases it.

[0110] Therefore, when the opening degree of the throttling device 6 is already greater than the second set opening degree and the suction superheat of the compressor 10 is still greater than the set superheat, it indicates that it is no longer possible to reduce the suction superheat of the compressor 10 and thus improve system energy efficiency by increasing the opening degree of the throttling device 6. This may be because the piping is too long and the resistance is too high, resulting in excessive suction superheat of the compressor 10. Therefore, the pressure can be increased by turning on the refrigerant pump 4 to offset the pressure drop in the piping, allowing more liquid refrigerant to enter the evaporator, thereby reducing the suction superheat of the compressor 10 and improving system energy efficiency. Thus, it can be determined that the system has switched to hybrid refrigeration mode.

[0111] In some exemplary embodiments, the control method further includes:

[0112] Based on the dual-cycle refrigeration system, after switching from compressor mode 10 to hybrid refrigeration mode, it switches back to compressor refrigeration mode within a preset time to increase the set superheat.

[0113] The preset time can be set as needed, and there are no restrictions here.

[0114] This avoids frequent switching between compressor cooling mode and hybrid cooling mode in a short period of time, thus preventing frequent mode switching caused by accidental triggering.

[0115] The method of increasing the set superheat can be: increasing the set superheat by a set value (such as 2℃); multiplying the set superheat by a certain coefficient; or assigning a value to the set superheat according to a preset curve or reference table showing the relationship between preset time and set superheat.

[0116] In one embodiment, such as Figure 4As shown, the control method includes the following steps:

[0117] Step S402: System operation;

[0118] Step S404: Determine whether the system is in compressor cooling mode. If yes, proceed to step S406; otherwise, return to step S402.

[0119] Step S406: Obtain the current operating parameters of the system;

[0120] Step S408: Determine whether the following conditions are met: the opening degree of the throttling device is greater than the second set opening degree, and the suction superheat of the compressor is greater than the set superheat. If yes, proceed to step S410; if no, return to step S406.

[0121] Step S410: The control system enters the hybrid cooling mode.

[0122] In related technologies, when the system switches from compressor cooling mode to refrigerant pump cooling mode, compressor 10 is directly turned off and refrigerant pump 4 is turned on. However, refrigerant pump 4 requires a certain amount of time to start up, meaning that the refrigerant pump cooling mode also requires a certain amount of time to truly exert its cooling effect. This process can lead to insufficient cooling capacity of the system. Similarly, when the system switches from refrigerant pump cooling mode to compressor cooling mode, refrigerant pump 4 is directly turned off and compressor 10 is turned on. However, compressor 10 also requires a certain amount of time to start up, meaning that the compressor cooling mode also requires a certain amount of time to truly exert its cooling effect. This process can also lead to insufficient cooling capacity of the system.

[0123] In some exemplary embodiments, the control method further includes:

[0124] Under compressor refrigeration mode, the conditions for switching to refrigerant pump refrigeration mode are met;

[0125] The compressor 10 is controlled to operate at a lower frequency, and the refrigerant pump 4 is controlled to start softly. The opening degree of the throttling device 6 is controlled according to the superheat of the compressor 10.

[0126] Based on the compressor 10 frequency decreasing to the first set frequency and the refrigerant pump 4 frequency increasing to the second set frequency, the compressor 10 is turned off, and the throttling device 6 is opened to the fully open state, so that the dual-cycle refrigeration system switches to the refrigerant pump refrigeration mode.

[0127] The switching condition for the refrigerant pump cooling mode can be: the outdoor ambient temperature reaches the set temperature corresponding to the switch from compressor cooling mode to refrigerant pump cooling mode. The first set frequency can be the minimum operating frequency of compressor 10. The second set frequency is the frequency corresponding to the starting platform of refrigerant pump 4, that is, the frequency reached when refrigerant pump 4 completes the starting platform. When the frequency of refrigerant pump 4 rises to the second set frequency, it indicates that refrigerant pump 4 has completed the starting platform, that is, the starting process is complete, and the frequency can be adjusted as needed afterwards.

[0128] In this way, during the process of switching the system from compressor refrigeration mode to refrigerant pump refrigeration mode, the compressor 10 can continue to operate at a low speed, so that there is always liquid refrigerant flowing in the evaporator. It can absorb indoor heat through evaporation, so the system still has refrigeration capacity, and the refrigeration capacity is not significantly reduced compared to the stable operation process. This ensures that the system's refrigeration capacity does not fluctuate drastically during the process of switching from compressor refrigeration mode to refrigerant pump refrigeration mode.

[0129] When the compressor 10 frequency drops to the first set frequency and the refrigerant pump 4 frequency rises to the second set frequency, it indicates that the refrigerant pump 4 has completed its startup phase and can be adjusted in frequency as needed. Since the compressor 10 frequency has already dropped to its minimum operating frequency, shutting it down will not affect the normal operation of the refrigerant pump 4. The throttling device 6 is opened to its full open position to prevent it from generating resistance and increasing the power consumption of the refrigerant pump 4. At this time, the refrigerant pump 4 can be regulated according to the logic of the refrigerant pump refrigeration mode, i.e., the system enters the refrigerant pump refrigeration mode.

[0130] Because compressor 10 and refrigerant pump 4 operate simultaneously during the switching from compressor refrigeration mode to refrigerant pump refrigeration mode, there is a mixed refrigeration mode as a transition during the switching between these two modes, so that the system's refrigeration capacity does not fluctuate drastically.

[0131] This control method is independent of the control methods in the aforementioned embodiments (such as the hybrid refrigeration mode control method and the method for switching between compressor refrigeration mode and hybrid refrigeration mode), and each can be implemented independently.

[0132] In some embodiments, the control method further includes: controlling the speed of the outdoor fan 2 according to the discharge pressure of the compressor 10 during the process of switching from compressor refrigeration mode to refrigerant pump refrigeration mode.

[0133] This ensures that during the process of switching compressor 10 to refrigerant pump refrigeration mode, condenser 1 has a suitable condensing pressure, guaranteeing that the system still has a high refrigeration capacity during the low-speed operation of compressor 10.

[0134] In some embodiments, controlling the compressor 10 to operate at a reduced frequency includes: controlling the compressor 10 to gradually reduce its frequency to a first set frequency at a first rate. In other words, the compressor 10 reduces its frequency to the first set frequency at a constant speed. Of course, the compressor 10 may also reduce its frequency to the first set frequency in a non-constant speed manner.

[0135] Controlling the soft start of the refrigerant pump 4 includes: controlling the refrigerant pump 4 to gradually increase its frequency to a second set frequency at a second rate. In other words, the refrigerant pump 4 increases its frequency to the second set frequency at a constant rate. Of course, the refrigerant pump 4 can also increase its frequency to the second set frequency at a non-constant rate.

[0136] Opening the throttling device 6 to the fully open state includes controlling the throttling device 6 to open to the fully open state at a third rate. In other words, the throttling device 6 opens to the fully open state at a constant speed. Of course, the throttling device 6 can also open to the fully open state at a non-constant speed.

[0137] The first set frequency is the minimum operating frequency of the compressor 10, and the second set frequency is the operating frequency corresponding to the starting platform of the refrigerant pump 4.

[0138] In one embodiment, such as Figure 5 As shown, the control method includes the following steps:

[0139] Step S502: The system operates in compressor refrigeration mode;

[0140] Step S504: Determine whether the conditions for switching the refrigerant pump refrigeration mode are met; if yes, proceed to step S506; if no, return to step S502.

[0141] Step S506: Control the compressor to reduce its frequency to the first set frequency and control the refrigerant pump to start softly. Control the opening of the throttling device according to the superheat of the compressor and control the speed of the outdoor fan according to the discharge pressure of the compressor.

[0142] Step S508: Determine whether the refrigerant pump frequency has been increased to the second set frequency. If yes, proceed to step S510; otherwise, return to step S508.

[0143] Step S510: Turn off the compressor, open the throttling device to the fully open state, and control the refrigerant pump and outdoor fan according to the refrigerant pump refrigeration mode logic.

[0144] In some exemplary embodiments, the control method further includes:

[0145] In refrigerant pump refrigeration mode, the conditions for switching compressor refrigeration mode are met;

[0146] The compressor 10 is controlled to start softly, and the refrigerant pump 4 is controlled to operate at a reduced frequency. The opening of the throttling device 6 is reduced to the initial opening of the compressor in refrigeration mode. Then, the opening of the throttling device 6 is controlled according to the superheat of the compressor 10.

[0147] Based on the compressor 10 frequency increasing to the third set frequency and the refrigerant pump 4 frequency decreasing to the fourth set frequency, the refrigerant pump 4 is turned off, causing the dual-cycle refrigeration system to switch to compressor refrigeration mode.

[0148] The compressor cooling mode switching condition can be: the outdoor ambient temperature reaches the set temperature corresponding to the switch from refrigerant pump cooling mode to compressor cooling mode. The fourth set frequency can be the minimum operating frequency of refrigerant pump 4. The third set frequency can be the frequency corresponding to the starting platform of compressor 10, that is, the frequency reached when compressor 10 completes the starting platform. When the frequency of compressor 10 rises to the third set frequency, it indicates that compressor 10 has completed the starting platform, that is, the starting process is complete, and the frequency can be adjusted as needed afterwards.

[0149] In this way, during the process of switching the system from refrigerant pump refrigeration mode to compressor refrigeration mode, refrigerant pump 4 can continue to operate at a low speed, so that there is always liquid refrigerant flowing in the evaporator. It can absorb indoor heat through evaporation, so the system still has refrigeration capacity. Compared with the stable operation process, the refrigeration capacity is not greatly reduced, ensuring that the system's refrigeration capacity does not fluctuate drastically during the process of switching from refrigerant pump refrigeration mode to compressor refrigeration mode.

[0150] When the frequency of compressor 10 increases to the third set frequency and the frequency of refrigerant pump 4 decreases to the fourth set frequency, it indicates that compressor 10 has completed its startup phase and its frequency can be adjusted as needed. Meanwhile, the frequency of refrigerant pump 4 has decreased to the minimum operating frequency, and even if it is shut down, it will not affect the normal operation of compressor 10. At this time, compressor 10 and throttling device 6 can be regulated according to the logic of the compressor refrigeration mode, i.e., the system enters compressor refrigeration mode.

[0151] Because compressor 10 and refrigerant pump 4 operate simultaneously during the switching from refrigerant pump refrigeration mode to compressor refrigeration mode, there is a mixed refrigeration mode as a transition during the switching process between these two modes, so that the system's refrigeration capacity does not fluctuate drastically.

[0152] This control method is independent of the control methods in the aforementioned embodiments (such as the hybrid refrigeration mode control method, the method for switching between compressor refrigeration mode and hybrid refrigeration mode, and the method for switching from compressor refrigeration mode to refrigerant pump refrigeration mode), and each can be implemented independently.

[0153] In some embodiments, the control method further includes:

[0154] During the process of switching from refrigerant pump refrigeration mode to compressor refrigeration mode, the speed of outdoor fan 2 is controlled according to the discharge pressure of compressor 10.

[0155] This ensures that during the switching from refrigerant pump refrigeration mode to compressor refrigeration mode, condenser 1 has a suitable condensing pressure, guaranteeing that the system still has a high refrigeration capacity during the low-speed operation of refrigerant pump 4.

[0156] In some embodiments, controlling the compressor 10 to soft start includes controlling the compressor 10 to gradually increase its frequency to a third preset frequency at a fourth rate. In other words, the compressor 10 increases its frequency to the third preset frequency at a constant speed. Of course, the compressor 10 can also increase its frequency to the third preset frequency in a non-constant speed manner.

[0157] Controlling the refrigerant pump 4 to reduce its frequency operation includes: controlling the refrigerant pump 4 to gradually reduce its frequency to the fourth preset frequency at a fifth rate. In other words, the refrigerant pump 4 reduces its frequency to the fourth preset frequency at a constant speed. Of course, the refrigerant pump 4 can also reduce its frequency to the fourth preset frequency at a non-constant speed.

[0158] Reducing the opening of the throttling device 6 to the initial opening of the compressor cooling mode includes: controlling the throttling device 6 to reduce its opening at a sixth rate to the initial opening of the compressor cooling mode. In other words, the throttling device 6 reduces its opening to the initial opening of the compressor cooling mode at a constant rate. Of course, the throttling device 6 can also reduce its opening to the initial opening of the compressor cooling mode at a non-constant rate.

[0159] In one embodiment, such as Figure 6 As shown, the control method includes the following steps:

[0160] Step S602: The system operates in refrigerant pump refrigeration mode;

[0161] Step S604: Determine whether the compressor cooling mode switching condition is met; if yes, proceed to step S606; if no, return to step S602.

[0162] Step S606: Control the compressor to start softly and control the refrigerant pump to run at the fourth set frequency. Reduce the opening of the throttling device to the initial opening of the compressor in cooling mode. Then, control the opening of the throttling device according to the superheat of the compressor and control the speed of the outdoor fan according to the discharge pressure of the compressor.

[0163] Step S608: Determine whether the compressor frequency has been increased to the third set frequency. If yes, proceed to step S610; otherwise, return to step S608.

[0164] Step S610: Turn off the refrigerant pump and control the compressor, throttling device, and outdoor fan according to the compressor refrigeration mode logic.

[0165] This application also provides a control device, including a processor and a memory storing a computer program. When the processor executes the computer program, it implements the steps of any of the above embodiments of the fluorine pump starting method, and thus has all the above-mentioned beneficial effects, which will not be repeated here.

[0166] The processor may be an integrated circuit chip with signal processing capabilities. The aforementioned processor can be a general-purpose processor, 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), an On-Premises Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor.

[0167] This application also provides a dual-cycle refrigeration system, including the control device as described in the above embodiments, and thus has all the above-mentioned beneficial effects, which will not be repeated here.

[0168] This application also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the fluorine pump starting method as described in any of the above embodiments, and thus has all the above-mentioned beneficial effects, which will not be repeated here.

[0169] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0170] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0171] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0172] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0173] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0174] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

[0175] In any one or more of the exemplary embodiments described above, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored as one or more instructions or code on or transmitted via a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium may comprise a computer-readable storage medium corresponding to a tangible medium such as a data storage medium, or a communication medium comprising any medium facilitating the transfer of a computer program from one place to another, for example, according to a communication protocol. In this manner, a computer-readable medium may generally correspond to a non-transitory tangible computer-readable storage medium or a communication medium such as a signal or carrier wave. The data storage medium may be any available medium accessible by one or more computers or one or more processors to retrieve instructions, code, and / or data structures for implementing the techniques described in this disclosure. Computer program products may comprise computer-readable media.

[0176] For example, and not as a limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible by a computer. Furthermore, any connection may also be referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but rather refer to non-transient tangible storage media. As used herein, disks and optical discs include compact optical discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, or Blu-ray discs, where disks typically reproduce data magnetically, while optical discs use lasers to reproduce data optically. The above combinations should also be included within the scope of computer-readable media.

[0177] For example, instructions can be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Therefore, the term "processor" as used herein can refer to any of the above-described structures or any other structures suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein can be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into combined codecs. Furthermore, the techniques can be fully implemented in one or more circuit or logic elements.

[0178] The technical solutions of the embodiments of this disclosure can be implemented in a wide variety of devices or equipment, including wireless mobile phones, integrated circuits (ICs), or a set of ICs (e.g., chipsets). Various components, modules, or units are described in the embodiments of this disclosure to emphasize functional aspects of a device configured to perform the described techniques, but they do not necessarily need to be implemented through different hardware units. Rather, as described above, the various units can be combined in codec hardware units or provided by a collection of interoperable hardware units (including one or more processors as described above) combined with suitable software and / or firmware.

Claims

1. A control method for a dual cycle refrigeration system, comprising: The control method comprises: obtaining the operating parameters of the double-circulation refrigeration system; determining the superheat of the compressor according to the operating parameters of the double-circulation refrigeration system, the superheat being the suction superheat or the discharge superheat of the compressor; in the mixed refrigeration mode, controlling the throttling device and the fluorine pump according to the superheat of the compressor; wherein, the controlling the throttling device and the fluorine pump according to the superheat of the compressor comprises: based on the superheat of the compressor being less than the preset target superheat and the difference being less than the second threshold value, the second threshold value being less than 0℃, adjusting the speed of the fluorine pump according to the preset target superheat, so that the superheat of the compressor approaches the preset target superheat; based on the speed of the fluorine pump being reduced to the set minimum speed and the superheat of the compressor still being less than the preset target superheat and the difference being less than the second threshold value, controlling the fluorine pump to keep the current speed, adjusting the opening of the throttling device according to the preset target superheat, so that the superheat of the compressor approaches the preset target superheat; based on the speed of the fluorine pump being the set minimum speed, the opening of the throttling device being less than the first set opening, the superheat of the compressor still being less than the preset target superheat and the difference being less than the second threshold value, controlling the double-circulation refrigeration system to switch to the compressor refrigeration mode, the first set opening being less than 100%.

2. The control method according to claim 1, characterized by, the controlling the throttling device and the fluorine pump according to the superheat of the compressor comprises: based on the superheat of the compressor being greater than the preset target superheat and the difference being greater than the first threshold value, the first threshold value being greater than 0℃, adjusting the opening of the throttling device according to the preset target superheat, so that the superheat of the compressor approaches the preset target superheat; based on the opening of the throttling device reaching the set maximum opening in the mixed refrigeration mode and the superheat of the compressor still being greater than the preset target superheat and the difference being greater than the first threshold value, controlling the throttling device to keep the current opening, adjusting the speed of the fluorine pump according to the preset target superheat, so that the superheat of the compressor approaches the preset target superheat.

3. The control method according to claim 1 or 2, characterized by, further comprising: in the compressor refrigeration mode, determining whether to switch to the mixed refrigeration mode according to the operating parameters of the double-circulation refrigeration system.

4. The control method according to claim 3, characterized by the operating parameters of the double-circulation refrigeration system comprise the working parameters of the throttling device and the working parameters of the compressor; the determining whether to switch to the mixed refrigeration mode according to the operating parameters of the double-circulation refrigeration system comprises: determining whether to switch to the mixed refrigeration mode according to the working parameters of the throttling device and the working parameters of the compressor.

5. The control method according to claim 4, characterized by the working parameters of the throttling device comprise the opening of the throttling device, and the working parameters of the compressor comprise the superheat of the compressor; the determining whether to switch to the mixed refrigeration mode according to the working parameters of the throttling device and the working parameters of the compressor comprises: based on the opening of the throttling device being greater than the second set opening and the superheat of the compressor being greater than the set superheat, determining that the double-circulation refrigeration system switches to the mixed refrigeration mode, the second set opening being less than 100%.

6. The control method according to claim 5, characterized by further comprising: Based on the double-cycle refrigeration system switching from the compressor mode to the mixed refrigeration mode and then switching back to the compressor refrigeration mode within a preset time, the set superheat degree is increased.

7. The control method according to claim 1, characterized by, Further comprising: In the compressor refrigeration mode, it is determined that the fluorine pump refrigeration mode switching condition is met; In the compressor refrigeration mode, it is determined that the fluorine pump refrigeration mode switching condition is met; The compressor is controlled to run at a reduced frequency, the fluorine pump is controlled to soft start, and the opening degree of the throttling device is controlled according to the superheat degree of the compressor; 8. The control method according to claim 1, characterized by, Based on the compressor frequency being reduced to a first set frequency and the fluorine pump frequency being increased to a second set frequency, the compressor is turned off, the throttling device is opened to a full open state, and the double-cycle refrigeration system is switched to the fluorine pump refrigeration mode. Further comprising: In the fluorine pump refrigeration mode, it is determined that the compressor refrigeration mode switching condition is met; In the fluorine pump refrigeration mode, it is determined that the compressor refrigeration mode switching condition is met; 9. The control method according to claim 7 or 8, characterized by, The compressor is controlled to soft start, the fluorine pump is controlled to run at a reduced frequency, and the opening degree of the throttling device is reduced to the initial opening degree of the compressor refrigeration mode, and then the opening degree of the throttling device is controlled according to the superheat degree of the compressor; Based on the compressor frequency being increased to a third set frequency and the fluorine pump frequency being reduced to a fourth set frequency, the fluorine pump is turned off, and the double-cycle refrigeration system is switched to the compressor refrigeration mode. Further comprising:

10. A control device characterized by comprising: In the process of switching from the compressor refrigeration mode to the fluorine pump refrigeration mode, the speed of the outdoor fan is controlled according to the exhaust pressure of the compressor; 11. A dual cycle refrigeration system characterized by, In the process of switching from the fluorine pump refrigeration mode to the compressor refrigeration mode, the speed of the outdoor fan is controlled according to the exhaust pressure of the compressor.

12. A computer readable storage medium storing a computer program, wherein the computer program comprises program instructions configured to cause a processor to perform the method according to any one of claims 1 to 11. The control device comprises a processor and a memory storing a computer program, and the processor executes the computer program to realize the steps of the control method according to any one of claims 1 to 9. The control device according to claim 10. The computer program is executed by the processor to realize the control method according to any one of claims 1 to 9.

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