Mode switching method and device of fluorine pump double-cycle air conditioner and air conditioner system

Abstract

The application provides a mode switching method and device of a fluorine pump double-circulation air conditioner and an air conditioner system, which comprises the following steps: when the air conditioner unit is running in a fluorine pump mode, if a mode switching signal is acquired, the frequency of the fluorine pump is reduced and the target superheat of the evaporator is increased; the running parameters of the air conditioner unit are acquired, and whether the set switching preparation condition is met is judged according to the running parameters; if yes, the fluorine pump is turned off and the superheat of the evaporator is adjusted to the default superheat in the compressor mode; and the running mode of the air conditioner unit is switched to the compressor mode. After the mode switching signal is acquired, before the compressor mode is switched, the frequency of the fluorine pump is reduced and the target superheat of the evaporator is increased, more liquid refrigerant is left in the condenser due to the reduction of the frequency of the fluorine pump, a larger proportion of the liquid refrigerant is converted into gaseous refrigerant in the evaporator, the proportion of the gaseous refrigerant in the refrigerant circulating in the air conditioner unit gradually increases, and finally the possibility of the occurrence of the compressor liquid knock problem is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of precision air conditioning control, and in particular to a mode switching method, device and air conditioning system for a refrigerant pump dual-cycle air conditioner. Background Technology

[0002] Currently, due to the inherent installation and energy efficiency advantages of refrigerant pump dual-cycle air conditioners in data center energy-saving renovations, they have been gradually used as precision air conditioners in data centers in some regions.

[0003] In a dual-cycle air conditioner with a refrigerant pump, the refrigerant circulates in a gaseous state in compressor mode, while the refrigerant pump circulates in a liquid state. When the operating modes are switched, especially when the refrigerant pump and compressor switch operating modes, there is a possibility that more liquid refrigerant may enter the compressor from the pure liquid refrigerant circuit of the refrigerant pump, which may lead to a risk of liquid slugging during startup. Summary of the Invention

[0004] The main objective of this invention is to provide a refrigerant pump dual-cycle air conditioning control method, device, and refrigerant pump dual-cycle air conditioning system, aiming to solve the problem that when the refrigerant pump mode is switched to the compressor mode, a large amount of liquid refrigerant may enter the compressor, causing liquid slugging.

[0005] In a first aspect, the present invention provides a mode switching method for a refrigerant pump dual-cycle air conditioner, which adopts the following scheme:

[0006] A method for switching modes in a refrigerant pump dual-cycle air conditioner, comprising:

[0007] When the unit is running in refrigerant pump mode, if a mode switching signal is received, the frequency of the refrigerant pump will be reduced and the target superheat of the evaporator will be increased.

[0008] Obtain the unit's operating parameters and determine whether the set switching preparation conditions are met based on the operating parameters;

[0009] If the conditions are met, shut down the refrigerant pump and adjust the superheat of the evaporator to the default superheat in compressor mode;

[0010] Switch the unit's operating mode to compressor mode.

[0011] In some embodiments, the reduction of the refrigerant pump frequency and the increase of the target superheat of the evaporator are achieved by continuously reducing the refrigerant pump frequency until the operating parameters meet the switching preparation conditions, or by reducing the refrigerant pump frequency to a set transition frequency.

[0012] In some embodiments, the frequency of the fluorine pump is continuously reduced until the operating parameters meet the switching preparation conditions, by reducing the frequency of the fluorine pump according to a preset curve, or by adjusting the frequency reduction rate of the fluorine pump according to the inlet subcooling of the fluorine pump.

[0013] In some embodiments, the rate at which the frequency of the refrigerant pump is reduced is adjusted according to the inlet subcooling of the refrigerant pump.

[0014] If the inlet subcooling of the refrigerant pump is higher than the set first temperature, the frequency of the refrigerant pump will be reduced at the set first frequency reduction rate.

[0015] If the inlet subcooling of the fluorine pump is lower than the first temperature but higher than the set second temperature, the frequency of the fluorine pump is reduced at a set second frequency reduction rate that is lower than the first frequency reduction rate.

[0016] If the inlet subcooling of the fluorine pump is lower than the second temperature, the frequency of the fluorine pump is reduced at a third frequency reduction rate that is less than the second frequency reduction rate.

[0017] In some embodiments, the reduction of the refrigerant pump frequency and the increase of the target superheat of the evaporator are described, whereby the target superheat of the evaporator is increased to a level not less than the default superheat of the evaporator in compressor mode.

[0018] In some embodiments, when the unit is running in refrigerant pump mode, if a mode switching signal is received, the internal fan speed is adjusted to a set transition speed.

[0019] If the refrigerant pump is shut down and the superheat of the evaporator is adjusted to the default superheat in compressor mode, the internal fan speed is adjusted to the default speed in compressor mode.

[0020] In some embodiments, when the unit is operating in refrigerant pump mode, if a mode switching signal is received, the frequency of the refrigerant pump is reduced and the target superheat of the evaporator is increased.

[0021] If the hydraulic solenoid valve and electronic expansion valve in the unit are connected in series, adjust both to their maximum opening.

[0022] If the hydraulic solenoid valve and the electronic expansion valve in the unit are connected in parallel, close the hydraulic solenoid valve and adjust the opening of the electronic expansion valve to the maximum.

[0023] In some embodiments, determining whether the set switching preparation conditions are met based on the unit's operating parameters after reducing the refrigerant pump frequency and increasing the target superheat of the evaporator includes the following steps:

[0024] Determine whether the unit's operating time after reducing the refrigerant pump frequency and increasing the target superheat of the evaporator is greater than the set time, and / or whether the actual superheat of the evaporator is greater than the set superheat;

[0025] If the actual superheat is greater than the set time and the actual superheat is greater than the set superheat, then the set switching preparation conditions are met.

[0026] Secondly, the present invention also provides a mode switching device for a refrigerant pump dual-cycle air conditioner, which adopts the following technical solution:

[0027] A mode switching device for a refrigerant pump dual-cycle air conditioner, comprising:

[0028] The adjustment module is configured to, when the unit is running in refrigerant pump mode, reduce the frequency of the refrigerant pump and increase the target superheat of the evaporator if a mode switching signal is received; and to acquire the operating parameters of the unit and determine whether the set switching preparation conditions are met based on the operating parameters; if met, shut down the refrigerant pump and adjust the superheat of the evaporator to the default superheat of the compressor mode.

[0029] The switching module is configured to switch the unit's operating mode to compressor mode after shutting down the refrigerant pump and adjusting the evaporator's superheat to the default superheat in compressor mode.

[0030] Thirdly, the present invention also provides a refrigerant pump dual-cycle air conditioning system, which adopts the following technical solution:

[0031] A refrigerant pump dual-cycle air conditioning system includes a mode switching device as described above.

[0032] The present invention provides a mode switching method, apparatus, and air conditioning system for a dual-cycle refrigerant pump air conditioner. After receiving the mode switching signal, before switching to compressor mode, it reduces the frequency of the refrigerant pump and increases the target superheat of the evaporator. This results in more liquid refrigerant remaining in the condenser due to the reduced pump frequency, while the refrigerant flowing from the condenser into the evaporator is converted to gaseous refrigerant in a larger proportion due to the increased target superheat. This continuous process gradually increases the proportion of gaseous refrigerant and decreases the proportion of liquid refrigerant in the refrigerant circulating in the unit. Finally, after meeting the set switching preparation conditions, the refrigerant can smoothly enter the compressor while effectively reducing the possibility of liquid slugging. Furthermore, this frequency reduction process between switching to refrigerant pump mode and shutting down the pump allows for a smoother shutdown, significantly improving the system's operational stability during the switching process. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the hardware structure of the mode switching device for the refrigerant pump dual-cycle air conditioner involved in the embodiment of the present invention;

[0034] Figure 2 This is a flowchart illustrating the first embodiment of the mode switching method for the refrigerant pump dual-cycle air conditioner of the present invention.

[0035] Figure 3This is a schematic diagram of the functional modules of the mode switching device of the refrigerant pump dual-cycle air conditioner of the present invention.

[0036] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0038] Currently, due to the inherent installation and energy efficiency advantages of refrigerant pump dual-cycle air conditioners in data center energy-saving renovations, they have been gradually used as precision air conditioners in data centers in some regions.

[0039] In a dual-cycle air conditioner with a refrigerant pump, the refrigerant circulates in a gaseous state in compressor mode, while the refrigerant pump circulates in a liquid state. When the operating modes are switched, especially when the refrigerant pump and compressor switch operating modes, there is a possibility that more liquid refrigerant may enter the compressor from the pure liquid refrigerant circuit of the refrigerant pump, which may lead to a risk of liquid slugging during startup.

[0040] Therefore, this application proposes a mode switching method, device, and air conditioning system for a refrigerant pump dual-cycle air conditioner. The key point of the invention is that, after receiving the mode switching signal and before switching to compressor mode, by reducing the frequency of the refrigerant pump and increasing the target superheat of the evaporator, more liquid refrigerant is retained in the condenser due to the reduced pump frequency. Simultaneously, the refrigerant flowing from the condenser into the evaporator is converted into gaseous refrigerant in a larger proportion due to the increased target superheat of the evaporator. Thus, in this continuous process, the proportion of gaseous refrigerant gradually increases and the proportion of liquid refrigerant gradually decreases in the refrigerant circulating in the unit. Finally, after meeting the set switching preparation conditions, the refrigerant can smoothly enter the compressor while effectively reducing the possibility of liquid slugging. Furthermore, because of this frequency reduction process between refrigerant pump mode and pump shutdown, the pump shutdown action can be achieved more smoothly, greatly improving the system's operational stability during the switching process.

[0041] In a first aspect, embodiments of the present invention provide a mode switching device for a refrigerant pump dual-cycle air conditioner. This mode switching device can be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0042] Reference Figure 1 , Figure 1This is a schematic diagram of the hardware structure of the mode switching device for a refrigerant pump dual-cycle air conditioner according to an embodiment of the present invention. In this embodiment, the mode switching device for the refrigerant pump dual-cycle air conditioner may include a processor 1001 (e.g., a Central Processing Unit, CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to realize communication between these components; the user interface 1003 may include a display screen or an input unit such as a keyboard; the network interface 1004 may optionally include a standard wired interface or a wireless interface (e.g., Wireless Fidelity, Wi-Fi); the memory 1005 may be high-speed random access memory (RAM) or non-volatile memory, such as a disk storage device; the memory 1005 may also optionally be a storage device independent of the aforementioned processor 1001. Those skilled in the art will understand that… Figure 1 The hardware structure shown does not constitute a limitation of the invention and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0043] Continue to refer to Figure 1 , Figure 1 The memory 1005, which serves as a computer storage medium, may include an operating system, a network communication module, a user interface module, and a mode switching program for a dual-cycle refrigerant pump air conditioner. The processor 1001 can call the mode switching program for the dual-cycle refrigerant pump air conditioner stored in the memory 1005 and execute the mode switching method for the dual-cycle refrigerant pump air conditioner provided in this embodiment of the invention.

[0044] Secondly, embodiments of the present invention provide a mode switching method for a refrigerant pump dual-cycle air conditioner.

[0045] Reference Figure 2 A method for switching modes in a refrigerant pump dual-cycle air conditioner, comprising:

[0046] S100. When the unit is running in refrigerant pump mode, if a mode switching signal is received, the frequency of the refrigerant pump will be reduced and the target superheat of the evaporator will be increased.

[0047] S200: Obtain the unit's operating parameters and determine whether the set switching preparation conditions are met based on the operating parameters;

[0048] S300, if satisfied, shut down the refrigerant pump and adjust the superheat of the evaporator to the default superheat in compressor mode;

[0049] S400, switch the unit's operating mode to compressor mode.

[0050] Specifically, in step S100, the frequency reduction of the refrigerant pump can vary in different implementations. For example, in some implementations, the refrigerant pump frequency is directly jumped to a lower frequency, or in others, the frequency is continuously reduced. It is understood that there needs to be an operating state with a frequency lower than the refrigerant pump frequency in normal operation between the pump's shutdown and startup. During this operating state, the target superheat of the evaporator is simultaneously increased to allow for a greater increase in the proportion of gaseous refrigerant in the refrigerant. In step S200, regarding the set switching preparation conditions, in some implementations, these conditions can be set based on the experimental results or experience of technical personnel. It is understood that these switching preparation conditions must ensure that the compressor enters operation when the proportion of gaseous and liquid refrigerant in the refrigerant is appropriate, thereby significantly reducing the possibility of compressor liquid slugging.

[0051] This configuration, upon receiving the mode switching signal but before switching to compressor mode, reduces the frequency of the refrigerant pump and increases the target superheat of the evaporator. This results in more liquid refrigerant remaining in the condenser due to the reduced pump frequency, while the refrigerant flowing from the condenser into the evaporator is converted to gaseous refrigerant in a larger proportion due to the increased superheat. This continuous process gradually increases the proportion of gaseous refrigerant and decreases the proportion of liquid refrigerant circulating in the unit. Ultimately, once the set switching preparation conditions are met, the refrigerant can smoothly enter the compressor while effectively reducing the possibility of liquid slugging. Furthermore, this frequency reduction process between switching to refrigerant pump mode and shutting down the pump allows for a smoother shutdown, significantly improving the system's operational stability during the switching process.

[0052] Furthermore, in step S100, regarding reducing the frequency of the refrigerant pump and increasing the target superheat of the evaporator, in some embodiments, the frequency of the refrigerant pump is continuously reduced until the operating parameters meet the switching preparation conditions; in other embodiments, the frequency of the refrigerant pump is reduced to a set transition frequency.

[0053] With this configuration, in step S100, the implementation method of continuously reducing the refrigerant pump frequency until it is shut down further improves the smoothness of the entire refrigerant pump shutdown process. The implementation method of reducing the refrigerant pump frequency to a set transition frequency allows for faster and more efficient refrigerant handling and migration, resulting in a quicker transition to compressor mode.

[0054] Furthermore, the frequency of the refrigerant pump is continuously reduced until the operating parameters meet the switching preparation conditions. The frequency of the refrigerant pump is reduced according to a preset curve, or the frequency reduction rate of the refrigerant pump is adjusted according to the inlet subcooling of the refrigerant pump.

[0055] In one implementation method for reducing the refrigerant pump frequency using a preset curve, the preset curve can be a linear or non-linear curve. The specific curve can be designed and determined in advance by technicians based on the refrigerant pump's operating frequency and the current unit's operating conditions, and will not be elaborated upon here. In other implementation methods, the frequency reduction rate of the refrigerant pump can be adjusted according to the inlet subcooling of the refrigerant pump, thereby ensuring that the refrigerant pump is in a better operating state and avoiding operational problems caused by excessively rapid frequency reduction, or low switching efficiency caused by excessively slow frequency reduction. Furthermore, in other embodiments, the frequency reduction rate of the refrigerant pump can also be dynamically adjusted according to other relevant parameters to achieve the relevant operational effects during the switching process.

[0056] Furthermore, the rate at which the frequency of the refrigerant pump decreases is adjusted based on the inlet subcooling of the refrigerant pump.

[0057] If the inlet subcooling of the refrigerant pump is higher than the set first temperature, the frequency of the refrigerant pump will be reduced at the set first frequency reduction rate.

[0058] If the inlet subcooling of the fluorine pump is lower than the first temperature but higher than the set second temperature, the frequency of the fluorine pump is reduced at a set second frequency reduction rate that is lower than the first frequency reduction rate.

[0059] If the inlet subcooling of the fluorine pump is lower than the second temperature, the frequency of the fluorine pump is reduced at a third frequency reduction rate that is less than the second frequency reduction rate.

[0060] In this embodiment, the first temperature is preferably 8 degrees; the first frequency reduction rate is not less than 2% / s of the difference between the maximum and minimum frequencies of the fluorine pump, specifically 4% / s; the second temperature is 4 degrees, and the second frequency reduction rate is not greater than 1% / s of the difference between the maximum and minimum frequencies of the fluorine pump, specifically 0.5% / s.

[0061] Furthermore, in some preferred embodiments, in step S100, reducing the frequency of the refrigerant pump and increasing the target superheat of the evaporator, the target superheat of the evaporator is increased to be no less than the default superheat of the evaporator in compressor mode.

[0062] This configuration allows for faster refrigerant migration, increasing the proportion of gaseous refrigerant entering the evaporator and thus accelerating the switch from refrigerant pump mode to compressor mode.

[0063] Furthermore, in some preferred embodiments, when the unit is running in refrigerant pump mode, if a mode switching signal is received, the internal fan speed is adjusted to a set transition speed.

[0064] If the refrigerant pump is shut down and the superheat of the evaporator is adjusted to the default superheat in compressor mode, the internal fan speed is adjusted to the default speed in compressor mode.

[0065] This configuration allows for adjustments to the unit's internal fan speed during mode switching, thereby improving the heat exchange efficiency between the refrigerant and the indoor environment. This, in turn, helps the refrigerant increase its gaseous refrigerant ratio more quickly after entering the evaporator, ultimately enabling a faster mode switching process.

[0066] Furthermore, in step S100, when the unit is operating in refrigerant pump mode, if a mode switching signal is received, the frequency of the refrigerant pump is reduced and the target superheat of the evaporator is increased. Different units will implement differentiated control based on the different installation methods of the internal liquid circuit solenoid valves and electronic expansion valves:

[0067] If the liquid circuit solenoid valve and the electronic expansion valve in the unit are connected in series, the liquid circuit solenoid valve is normally open, and the electronic expansion valve is adjusted according to the target superheat.

[0068] If the hydraulic solenoid valve and the electronic expansion valve in the unit are connected in parallel, close the hydraulic solenoid valve and adjust the opening of the electronic expansion valve to the maximum.

[0069] Thirdly, embodiments of the present invention also provide a mode switching device for a refrigerant pump dual-cycle air conditioner.

[0070] Reference Figure 3 A schematic diagram of the functional modules of the mode switching device of the refrigerant pump dual-circulation air conditioner in the first embodiment.

[0071] In this embodiment, the mode switching device of the refrigerant pump dual-cycle air conditioner includes:

[0072] The adjustment module is configured to, when the unit is running in refrigerant pump mode, reduce the frequency of the refrigerant pump and increase the target superheat of the evaporator if a mode switching signal is received; and to acquire the operating parameters of the unit and determine whether the set switching preparation conditions are met based on the operating parameters; if met, shut down the refrigerant pump and adjust the superheat of the evaporator to the default superheat of the compressor mode.

[0073] The switching module is configured to switch the unit's operating mode to compressor mode after shutting down the refrigerant pump and adjusting the evaporator's superheat to the default superheat in compressor mode.

[0074] The functions of each module in the above-mentioned refrigerant pump dual-cycle air conditioner mode switching device correspond to the steps in the above-mentioned refrigerant pump dual-cycle air conditioner mode switching method embodiment, and their functions and implementation processes will not be described in detail here.

[0075] Fourthly, embodiments of the present invention also provide a readable storage medium.

[0076] The present invention stores a mode switching program for a refrigerant pump dual-cycle air conditioner on a readable storage medium, wherein when the mode switching program for the refrigerant pump dual-cycle air conditioner is executed by a processor, the steps of the mode switching method for the refrigerant pump dual-cycle air conditioner as described above are implemented.

[0077] The method implemented when the mode switching procedure of the refrigerant pump dual-cycle air conditioner is executed can be referred to in various embodiments of the mode switching method of the refrigerant pump dual-cycle air conditioner of the present invention, and will not be repeated here.

[0078] Fifthly, embodiments of the present invention also provide a refrigerant pump dual-cycle air conditioning system.

[0079] A refrigerant pump dual-cycle air conditioning system includes a mode switching device as described above.

[0080] The working principle and beneficial effects of the refrigerant pump dual-cycle air conditioner mode switching method, device, and air conditioning system provided by this invention are as follows:

[0081] Upon receiving the mode switching signal, before switching to compressor mode, the frequency of the refrigerant pump is reduced and the target superheat of the evaporator is increased. This process ensures that more liquid refrigerant remains in the condenser due to the reduced pump frequency. Simultaneously, the refrigerant flowing from the condenser into the evaporator is converted to gaseous refrigerant in a larger proportion due to the increased evaporator superheat. This continuous process gradually increases the proportion of gaseous refrigerant and decreases the proportion of liquid refrigerant in the refrigerant circulating in the unit. Finally, once the set switching preparation conditions are met, the refrigerant can smoothly enter the compressor while effectively reducing the possibility of liquid slugging. Furthermore, this frequency reduction process between switching to refrigerant pump mode and shutting down the pump allows for a smoother shutdown, significantly improving the system's operational stability during the switching process.

[0082] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0083] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0084] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of the present invention.

[0085] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A mode switching method of a fluorine pump dual cycle air conditioner, characterized by, It comprises: When the unit is running in the fluorine pump mode, if a mode switching signal is obtained, the frequency of the fluorine pump is reduced and the target superheat degree of the evaporator is increased; Obtain the operating parameters of the unit, and determine whether the set switching preparation condition is met according to the operating parameters; If so, shut down the fluorine pump and adjust the superheat degree of the evaporator to the default superheat degree in the compressor mode; Switch the operating mode of the unit to the compressor mode; In the step of reducing the frequency of the fluorine pump and increasing the target superheat degree of the evaporator, the target superheat degree of the evaporator is increased to be not less than the default superheat degree of the evaporator in the compressor mode.

2. The mode switching method of a fluoro-pump dual cycle air conditioner according to claim 1, characterized in that, In the step of reducing the frequency of the fluorine pump and increasing the target superheat degree of the evaporator, the frequency of the fluorine pump is continuously reduced until the operating parameters meet the switching preparation condition, or the frequency of the fluorine pump is reduced to a set transition frequency.

3. The mode switching method of a fluoro-pump dual cycle air conditioner according to claim 2, characterized in that, In the step of continuously reducing the frequency of the fluorine pump until the operating parameters meet the switching preparation condition, the frequency of the fluorine pump is reduced according to a preset curve, or the frequency reduction speed of the fluorine pump is adjusted according to the inlet subcooling degree of the fluorine pump.

4. The mode switching method of a fluoro-pump dual cycle air conditioner according to claim 3, characterized in that, In the step of adjusting the frequency reduction speed of the fluorine pump according to the inlet subcooling degree of the fluorine pump, If the inlet subcooling degree of the fluorine pump is higher than a set first temperature, the frequency of the fluorine pump is reduced at a set first frequency reduction speed; If the inlet subcooling degree of the fluorine pump is lower than the first temperature and higher than a set second temperature, the frequency of the fluorine pump is reduced at a set second frequency reduction speed which is smaller than the first frequency reduction speed; If the inlet subcooling degree of the fluorine pump is lower than the second temperature, the frequency of the fluorine pump is reduced at a set third frequency reduction speed which is smaller than the second frequency reduction speed.

5. The mode switching method of a fluoro-pump dual cycle air conditioner according to any one of claims 1 to 4, characterized in that, When the unit is running in the fluorine pump mode, if a mode switching signal is obtained, the speed of the indoor fan is adjusted to a set transition speed; If the step of shutting down the fluorine pump and adjusting the superheat degree of the evaporator to the default superheat degree in the compressor mode, the speed of the indoor fan is adjusted to the default speed in the compressor mode.

6. The mode switching method of a fluoro-pump dual cycle air conditioner according to any one of claims 1 to 4, characterized in that, In the step of reducing the frequency of the fluorine pump and increasing the target superheat degree of the evaporator when the unit is running in the fluorine pump mode, If the liquid circuit electromagnetic valve and the electronic expansion valve in the unit are connected in series, the liquid circuit electromagnetic valve is always open, and the electronic expansion valve is adjusted according to the target superheat degree; If the liquid circuit electromagnetic valve and the electronic expansion valve in the unit are connected in parallel, the liquid circuit electromagnetic valve is closed, and the opening degree of the electronic expansion valve is adjusted to the maximum.

7. The mode switching method of a fluoro-pump dual cycle air conditioner according to any one of claims 1 to 4, characterized in that, The step of determining whether the set switching preparation condition is met according to the operating parameters of the unit after the frequency of the fluorine pump is reduced and the target superheat degree of the evaporator is increased comprises the following steps: Determine whether the operating time of the unit after the frequency of the fluorine pump is reduced and the target superheat degree of the evaporator is increased is greater than a set time, and whether the actual superheat degree of the evaporator is greater than a set superheat degree; If the operating time is greater than the set time and the actual superheat degree is greater than the set superheat degree, the set switching preparation condition is met.

8. A mode switching device for a fluorine pump dual cycle air conditioner, characterized by, It comprises: An adjusting module configured to, when the unit is running in the fluorine pump mode, if a mode switching signal is obtained, reduce the frequency of the fluorine pump and increase the target superheat degree of the evaporator; and obtain the operating parameters of the unit, and determine whether the set switching preparation condition is met according to the operating parameters; if so, shut down the fluorine pump and adjust the superheat degree of the evaporator to the default superheat degree in the compressor mode; The switching module is configured to switch the operation mode of the air conditioning unit to the compressor mode after shutting down the fluorine pump and adjusting the superheat degree of the evaporator to the default superheat degree in the compressor mode. The lowering the frequency of the fluorine pump and the increasing the target superheat degree of the evaporator include increasing the target superheat degree of the evaporator to be not less than the default superheat degree of the evaporator in the compressor mode.

9. A fluoro-compressor dual-cycle air conditioning system characterized by, The mode switching device of the fluorine pump double-cycle air conditioner includes the mode switching device according to claim 8.

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