Low-pressure pump-driven two-phase cooling system and working method

Abstract

The invention provides a low-pressure pump-driven two-phase cooling system and a working method. The system comprises a pump driving module and a pressure regulating module, the pump driving module comprises a liquid storage tank, a first filter, a precooler, a pump, a flow meter, a preheater, a heating element, a condenser and a reheater which are sequentially connected through pipelines, and the reheater returns to the liquid storage tank through a pipeline. The pressure regulating module comprises a low-pressure gas tank, a vacuum pump and a high-pressure gas tank, the liquid storage tank is respectively connected with the primary low-pressure gas tank and the high-pressure gas tank through two pipelines, the primary low-pressure gas tank is connected with the primary vacuum pump, the primary low-pressure gas tank is connected with the secondary low-pressure gas tank through a pipeline, and the secondary low-pressure gas tank is connected with the secondary vacuum pump. According to the pressure regulating module, various modes such as the high-pressure gas tank, the multi-stage low-pressure gas tank and the vacuum pump are comprehensively utilized, and the cooling capacity and stability of the pump-driven two-phase cooling system are effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft environment control systems, and in particular relates to a low-pressure pump-driven two-phase cooling system and a working method thereof. Background Art

[0002] With the miniaturization and integration of airborne electronic equipment, their power and heat flux are constantly increasing. However, traditional cooling technologies can no longer meet these heat dissipation requirements. As a new and efficient thermal control technology based on two-phase flow, pump-driven two-phase flow cooling technology has gradually become an important means to address the heat dissipation needs of high heat flux density and has gradually become a research hotspot in this field.

[0003] The efficient heat dissipation capability of the pump-driven two-phase flow cooling system is achieved by utilizing the latent heat effect of the refrigerant during the phase change process. Therefore, low-boiling-point coolants are often used at lower operating temperatures, which limits the use of high-latent-heat refrigerants and reduces the cooling efficiency of the system. Summary of the Invention

[0004] The purpose of the present invention is to solve the defects of the above-mentioned prior art and provide a low-pressure pump-driven two-phase cooling system and a method of use, which can improve the performance of the pump-driven two-phase flow cooling system.

[0005] The present invention adopts the following technical solutions: A low-pressure pump-driven two-phase cooling system includes a pump-driven module and a pressure regulating module. The pump-driven module includes a liquid storage tank, a first filter, a precooler, a pump, a flow meter, a preheater, a heating element, a condenser, and a reheater. The above components are connected in sequence through pipelines, and the reheater returns to the liquid storage tank through a pipeline. The pressure regulating module includes a low-pressure gas tank, a vacuum pump and a high-pressure gas tank. The liquid storage tank is connected to the first-level low-pressure gas tank and the high-pressure gas tank through two pipes respectively. The first-level low-pressure gas tank is connected to the first-level vacuum pump. The first-level low-pressure gas tank is connected to the second-level low-pressure gas tank through a pipe, and the second-level low-pressure gas tank is connected to the second-level vacuum pump.

[0006] Furthermore, the inlet of the precooling cold source is communicated with the second outlet of the precooler, and the outlet of the precooling cold source is communicated with the second inlet of the precooler.

[0007] Furthermore, the inlet of the condensation cold source is communicated with the second outlet of the condenser, and the outlet of the condensation cold source is communicated with the second inlet of the condenser.

[0008] Furthermore, the on-off valve is arranged on a pipeline connecting the liquid storage tank and the first filter.

[0009] The pump drive module further includes a flow meter, which is disposed on a pipeline between the pump and the preheater.

[0010] The pump drive module further includes a first sight glass, which is arranged on a pipeline between the flow meter and the preheater.

[0011] The pump drive module further includes a second sight glass, which is arranged on the pipeline between the preheater and the heating element.

[0012] The heating element is composed of a heating element unit and a heating element heat exchanger unit. The heating element unit corresponds to the heating element heat exchanger unit one by one. Multiple heating element units are connected in parallel. The inlet of the heating element heat exchanger unit is connected to the outlet of the preheater through a pipeline, and the outlet of the heating element heat exchanger unit is connected to the inlet of the condenser through a pipeline.

[0013] The pump drive module further includes a third sight glass, which is arranged on the pipeline between the heating element and the condenser.

[0014] The pump drive module further includes a precooling flow meter, which is arranged on a pipeline between the precooler and the precooling cold source.

[0015] The pump drive module further includes a pre-cooling on-off valve, which is arranged on a pipeline between the pre-cooler and the pre-cooling cold source.

[0016] The pump drive module further includes a condensation on-off valve, which is arranged on two pipes between the condenser and the condensation cold source.

[0017] A second filter is installed on the pipe connecting the liquid storage tank and the first-level low-pressure gas tank. The inlet of the second filter is connected to the top of the liquid storage tank via a pipe. The first-level pressure reducing valve is installed on the pipe connecting the liquid storage tank and the second filter. The second-level pressure reducing valve is installed on the pipe connecting the first-level low-pressure gas tank and the second-level low-pressure gas tank. The boosting valve is installed on the pipe connecting the liquid storage tank and the high-pressure gas tank.

[0018] On the other hand, a working method of a low-pressure pump-driven two-phase cooling system is provided, including four working states: When the pressure of the liquid storage tank in the SA pump drive module is at the rated working state, the on-off valve is opened, the boost valve, the first-stage pressure reducing valve and the second-stage pressure reducing valve are closed, and the refrigerant in the liquid storage tank flows into the first filter, then passes through the preheater, passes through the pump, the flow meter and the preheater, enters the heating element, then enters the condenser for processing, enters the reheater, and finally returns to the liquid storage tank.

[0019] SB. When the pressure of the liquid storage tank in the pump drive module is higher than the rated working state, the on-off valve opens, the boost valve and the secondary pressure reducing valve close, and the pressure reducing valve opens. The refrigerant gas in the liquid storage tank of the pump drive circuit flows to the first-level low-pressure gas tank in the pressure regulating module. The first-level vacuum pump is turned on intermittently according to the pressure in the first-level low-pressure gas tank. At the same time, the refrigerant in the liquid storage tank flows into the first filter, then passes through the preheater, passes through the pump, the flow meter and the preheater, enters the heating element, then enters the condenser for processing, enters the reheater, and finally returns to the liquid storage tank.

[0020] SB. When the pressure of the liquid storage tank in the pump drive module is higher than the rated working state, the on-off valve opens, the boost valve closes, the first-level pressure reducing valve and the second-level pressure reducing valve open, and the refrigerant gas in the liquid storage tank flows to the first-level low-pressure gas tank and the second-level low-pressure gas tank through the pipeline. The first-level vacuum pump and the second-level vacuum pump remain on. At the same time, the refrigerant in the liquid storage tank flows into the first filter, then passes through the preheater, passes through the pump, the flow meter and the preheater, enters the heating element, then enters the condenser for processing, enters the reheater, and finally returns to the liquid storage tank.

[0021] SD. When the pressure of the liquid storage tank in the pump drive module is lower than the rated operating state, the on-off valve opens, the first and second pressure reducing valves close, and the boost valve opens. The liquid storage tank obtains refrigerant gas from the high-pressure gas tank. At the same time, the refrigerant in the liquid storage tank flows into the first filter, then passes through the preheater, passes through the pump, flow meter and preheater, enters the heating element, then enters the condenser for processing, enters the reheater, and finally returns to the liquid storage tank.

[0022] Beneficial effects of the present invention: The present invention indirectly extracts refrigerant gas from the liquid storage tank through a first-level low-pressure gas tank to maintain a low pressure in the pump-driven two-phase system, which can reduce the saturation temperature of the coolant and make it easier for phase change to occur at a lower temperature, thereby efficiently absorbing the heat generated by the equipment and significantly improving the heat exchange efficiency.

[0023] Low pressure increases the coolant's latent heat utilization, reducing the flow rate required for single-phase flow, lowering both pump and system energy consumption. Furthermore, low-pressure operation effectively suppresses bubble accumulation and cavitation, preventing pump damage and flow rate fluctuations, and ensuring long-term system reliability. Maintaining low pressure also widens the two-phase heat exchange area, increasing the coolant's phase change zone within the heat exchanger of the heating element, thereby improving temperature uniformity and avoiding localized overheating and stress concentration.

[0024] The low-pressure environment reduces the mechanical stress on the system, reduces fatigue damage to pipes and cold plates, and extends the service life of the equipment. Furthermore, the use of multi-stage low-pressure gas tanks and vacuum pumps minimizes pressure fluctuations while maintaining extremely low pressure in the pump-driven system. This also reduces the operating pressure of a single vacuum pump, resulting in more stable system operation.

[0025] Finally, maintaining a lower pressure also helps the system flexibly select refrigerants under different heat loads and operating conditions, adjust the cooling capacity of the pump-driven two-phase cooling system, and improve the stability of the flow and heat transfer process inside the cold plate, which is more conducive to meeting the requirements of avionics equipment and high heat flux density applications for efficient and reliable thermal management. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic structural diagram of a low-pressure pump-driven two-phase cooling system provided by the present invention; Figure 2 This is a schematic diagram of the working process when the pressure in the liquid storage tank is higher than the rated low pressure; Figure 3 This is a schematic diagram of the working process when the pressure in the liquid storage tank is higher than the rated low pressure; Figure 4 This is a schematic diagram of the working process when the pressure in the liquid storage tank is at the rated low pressure; Figure 5 This is a schematic diagram of the working process when the pressure in the liquid storage tank is lower than the rated low pressure.

[0027] In the figure: 1-liquid storage tank, 2-first filter, 3-precooler, 4-pump, 5-preheater, 6-first heating element, 7-second heating element, 8-third heating element, 9-condenser, 10-reheater, 11-second filter, 12-first level low-pressure gas tank, 13-first level vacuum pump, 14-second level low-pressure gas tank, 15-second level vacuum pump, 16-high-pressure gas tank, 17-on-off valve, 18-precooling flowmeter, 19-precooling cold source, 20-precooling on-off valve, 21-flowmeter, 22-first sight glass, 23-second sight glass, 24-third sight glass, 25-condensation flowmeter, 26-condensation cold source, 27-condensation on-off valve, 28-first level pressure reducing valve I, 29-first level pressure reducing valve II, 30-boosting valve.

[0028] a-first pipeline, b-second pipeline, c-third pipeline, d-fourth pipeline, e-fifth pipeline, f-sixth pipeline, g-seventh pipeline, h-eighth pipeline, i-ninth pipeline, j-tenth pipelineⅩ, k-eleventh pipeline, l-twelfth pipeline, m-thirteenth pipeline, n-fourteenth pipeline, o-fifteenth pipeline, p-sixteenth pipeline, q-seventeenth pipeline, r-eighteenth pipeline. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] The present invention provides a low-pressure pump-driven two-phase cooling system and a working method. Airborne pump-driven two-phase cooling technology is currently an important research direction in the field of aviation thermal control. It mainly faces the problem of needing to select the corresponding boiling point refrigerant according to the operating temperature, which limits the use of high latent heat refrigerants and thus reduces the cooling efficiency of the system. In this way, the present invention uses a multi-stage low-pressure gas tank and a vacuum pump to extract the gas phase of the liquid storage tank in the pump-driven two-phase cooling system, so that the gas pressure in the liquid storage tank is always maintained at a low level. At the same time, considering that the gas pressure of the liquid storage tank in the pump-driven two-phase cooling system may also be in an excessively low pressure state during the extraction transition, a high-pressure gas tank is used to dynamically adjust it according to the pressure value in the liquid storage tank. This not only allows the pump-driven two-phase cooling system to maintain a low pressure, but also facilitates the system to flexibly select refrigerants under different heat loads and operating conditions, thereby improving the cooling capacity and stability of the pump-driven two-phase cooling system.

[0031] like Figure 1 As shown, a low-pressure pump-driven two-phase cooling system of the present invention includes a pump-driven module and a pressure regulating module. The pump-driven module includes: a liquid storage tank 1, a first filter 2, a precooler 3, a precooling cold source 19, a pump 4, a preheater 5, a first heating element 6, a second heating element 7, a third heating element 8, a condenser 9, a condensing cold source 26, a reheater 10, and an on-off valve 17.

[0032] The outlet of the liquid storage tank 1 is connected to the inlet of the first filter 2 via a first pipe a. The liquid storage tank 1 is used to store refrigerant for the pump-driven two-phase cooling system. The first outlet of the first filter 2 is connected to the first inlet of the precooler 3 via a second pipe b. The precooler 3 is used to reduce the coolant temperature before it enters the pump 4 to remove bubbles in the refrigerant and protect the pump 4. The first outlet of the precooler 3 is connected to the inlet of the pump 4 via a third pipe c. The outlet of the pump 4 is connected to the inlet of the preheater 5 via a fourth pipe d. The preheater 5 preheats the coolant to a predetermined temperature before it enters the cold plate or heat source area, thereby optimizing the phase change and heat exchange process of the system. The outlet of the preheater 5 is connected to the inlet of the heating element via a fifth pipe e. The outlet of the heating element is connected to the first inlet of the condenser 9 via a sixth pipe f. The first outlet of the condenser 9 is connected to the inlet of the reheater 10 via a seventh pipe g. The reheater 10 is used to increase the coolant dryness and improve the stability of the two-phase system. The outlet of the reheater 10 is connected to the inlet of the liquid storage tank 1 via an eighth pipe h. The inlet of the precooling cold source 19 is connected to the second outlet of the precooler 3 via a ninth pipe i. The outlet of the precooling cold source 19 is connected to the second inlet of the precooler 3 via a tenth pipe j. The inlet of the condensing cold source 26 is connected to the second outlet of the condenser 9 via an eleventh pipe k. The outlet of the condensing cold source 26 is connected to the second inlet of the condenser 9 via a twelfth pipe l. The on-off valve 17 is provided on the first pipe a.

[0033] The pump drive module further includes a flow meter 21 , which is disposed on a fourth pipe d between the pump 4 and the preheater 5 .

[0034] The pump drive module further includes a first sight glass 22 , which is disposed on a fourth pipe d between the flow meter 21 and the preheater 5 .

[0035] The pump drive module further includes a second sight glass 23 , which is disposed on a fifth pipe e between the preheater 5 and the heating element.

[0036] like Figure 1 As shown, the heating elements include a first heating element 6, a second heating element 7 and a third heating element 8. The inlets of the first heating element 6, the second heating element 7 and the third heating element 8 are all connected to the fifth pipe e, and the outlets of the first heating element 6, the second heating element 7 and the third heating element 8 are all connected to the sixth pipe f.

[0037] The heating element is composed of a heating element unit and a heating element heat exchanger unit. The heating element unit corresponds to the heating element heat exchanger unit one by one, and multiple heating element units are connected in parallel. The heating element unit includes but is not limited to high-power, high-heat-flow airborne equipment such as motors, lasers and radars. The inlet of the heating element heat exchanger unit is connected to the outlet of the preheater 5 through the fifth pipe e, and the outlet of the heating element heat exchanger unit is connected to the inlet of the condenser 9 through the sixth pipe f.

[0038] The pump drive module further includes a third sight glass 24 , which is disposed on a sixth pipe f between the heating element and the condenser 9 .

[0039] The pump drive module further includes a pre-cooling flow meter 18 , which is disposed on a ninth pipe i between the pre-cooler 3 and the pre-cooling cold source 19 .

[0040] The pump drive module further includes a pre-cooling on-off valve 20 , which is disposed on a tenth pipeline j between the pre-cooler 3 and the pre-cooling cold source 19 .

[0041] The pump drive module further includes a condensation on-off valve 27 , which is disposed on a twelfth pipe 1 between the condenser 9 and the condensation cold source 26 .

[0042] The pressure regulating module includes: a second filter 11, a first-level low-pressure gas tank 12, a first-level vacuum pump 13, a second-level low-pressure gas tank 14, a second-level vacuum pump 15, a high-pressure gas tank 16, a first-level pressure reducing valve 28, a second-level pressure reducing valve 29 and a boosting valve 30.

[0043] The inlet of the second filter 11 is connected to the top of the liquid storage tank 1 through the thirteenth pipe m, the outlet of the second filter 11 is connected to the inlet of the first-level low-pressure gas tank 12 through the fourteenth pipe n, the first outlet of the first-level low-pressure gas tank 12 is connected to the inlet of the first-level vacuum pump 13 through the fifteenth pipe o, the second outlet of the first-level low-pressure gas tank 12 is connected to the inlet of the second-level low-pressure gas tank 14 through the sixteenth pipe p, the outlet of the second-level low-pressure gas tank 14 is connected to the inlet of the second-level vacuum pump 15 through the seventeenth pipe q, the outlet of the high-pressure gas tank 16 is connected to the top of the liquid storage tank 1 through the eighteenth pipe r, the first-level pressure reducing valve 28 is arranged on the thirteenth pipe m, the second-level pressure reducing valve 29 is arranged on the sixteenth pipe p, and the boosting valve 30 is arranged on the eighteenth pipe r.

[0044] In actual applications, the liquid storage tank 1 , the first-level low-pressure gas tank 12 , the second-level low-pressure gas tank 14 and the high-pressure gas tank 16 all need to be equipped with pressure sensors.

[0045] The present invention further provides a working process of a low-pressure pump-driven two-phase cooling system, comprising: like Figure 2 As shown, when the pressure of the liquid storage tank 1 in the pump drive module is at the rated operating state, the on-off valve 17 is opened, the pump drive module maintains normal operation, and the boost valve 30, the first-level pressure reducing valve 28, and the second-level pressure reducing valve 29 are closed, disconnecting the pump drive module from the pressure regulating module. The refrigerant gas in the liquid storage tank 1 of the pump drive circuit does not exchange with the refrigerant gas in the first-level low-pressure gas tank 12 and the high-pressure gas tank 16 of the pressure regulating module. At the same time, the first-level vacuum pump 13 and the second-level vacuum pump 15 are turned off, and the pressure regulating circuit has no impact on the pump drive circuit.

[0046] The refrigerant in the liquid storage tank 1 flows into the first filter 2 to filter impurities, then passes through the precooler 3 to remove bubbles, passes through the pump 4 to increase the circulation power, and the amount of refrigerant is measured by the flow meter 21. Then it enters the preheater 5 for heating, enters the heating element, and takes away the heat generated by high-power, high-heat-flow airborne equipment such as motors, lasers and radars. Then it enters the condenser 9 to transfer the heat in the refrigerant to the condensation cold source, enters the reheater 10, and finally flows back to the liquid storage tank 1.

[0047] like Figure 3 As shown, when the pressure in the liquid storage tank 1 in the pump drive module is higher than the rated operating state, the on-off valve 17 opens, and the pump drive module maintains normal operation. The boost valve 30, the secondary pressure reducing valve 29, and the boost valve 30 are closed, and the pressure reducing valve 28 is opened. The refrigerant gas in the pump drive circuit liquid storage tank 1 exchanges with the refrigerant gas in the primary low-pressure gas tank 12 in the pressure regulating module. The liquid storage tank 1 reduces the pressure by transferring the refrigerant gas to the primary low-pressure gas tank 12. At the same time, the primary vacuum pump 13 is intermittently opened according to the pressure in the primary low-pressure gas tank 12, so that the primary low-pressure gas tank 12 always maintains a high vacuum level.

[0048] like Figure 4 As shown, when the pressure of the liquid storage tank 1 in the pump drive module is higher than the rated working state, the on-off valve 17 is opened and the pump drive module maintains normal operation. The boost valve 30 is closed, the first-level pressure reducing valve 28 and the second-level pressure reducing valve 29 are opened, and the refrigerant gas in the liquid storage tank 1 of the pump drive circuit is exchanged with the refrigerant gas in the first-level low-pressure gas tank 12 and the second-level low-pressure gas tank 14 in the pressure regulating module. The liquid storage tank 1 reduces the pressure by transferring the refrigerant gas to the first-level low-pressure gas tank 12 and the second-level low-pressure gas tank 14. At the same time, the first-level vacuum pump 13 and the second-level vacuum pump 15 remain open, respectively, so that the first-level low-pressure gas tank 12 and the second-level low-pressure gas tank 14 always maintain a high vacuum degree.

[0049] like Figure 5As shown, when the pressure in liquid storage tank 1 in the pump drive module falls below the rated operating state, on-off valve 17 opens, and the pump drive module maintains normal operation. The primary and secondary pressure reducing valves 28 and 29 close, and the boost valve 30 opens. The refrigerant gas in liquid storage tank 1 of the pump drive circuit exchanges with the refrigerant gas in the pressure regulating module. Liquid storage tank 1 increases its pressure by drawing refrigerant gas from high-pressure gas tank 16. Simultaneously, the primary and secondary vacuum pumps 13 and 15 are shut down.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A low-pressure pump-driven two-phase cooling system, characterized in that: It includes a pump drive module and a pressure regulating module. The pump drive module includes a liquid storage tank, a first filter, a precooler, a pump, a flow meter, a preheater, a heating element, a condenser, and a reheater. The above components are connected in sequence through pipelines, and the reheater returns to the liquid storage tank through a pipeline; The pressure regulating module includes a low-pressure gas tank, a vacuum pump and a high-pressure gas tank. The liquid storage tank is connected to the first-level low-pressure gas tank and the high-pressure gas tank through two pipes respectively. The first-level low-pressure gas tank is connected to the first-level vacuum pump. The first-level low-pressure gas tank is connected to the second-level low-pressure gas tank through a pipe, and the second-level low-pressure gas tank is connected to the second-level vacuum pump.

2. The system according to claim 1, wherein: The inlet of the precooling cold source is connected to the second outlet of the precooler, the outlet of the precooling cold source is connected to the second inlet of the precooler, the inlet of the condensing cold source is connected to the second outlet of the condenser, and the outlet of the condensing cold source is connected to the second inlet of the condenser. The on-off valve is arranged on the pipeline connecting the liquid storage tank and the first filter.

3. The system according to claim 1, wherein: The pump drive module also includes a flow meter, which is arranged on the pipe between the pump and the preheater. The pump drive module also includes a first sight glass, which is arranged on the pipe between the flow meter and the preheater. The pump drive module also includes a second sight glass, which is arranged on the pipe between the preheater and the heating element. The pump drive module also includes a third sight glass, which is arranged on the pipe between the heating element and the condenser. The pump drive module also includes a precooling flow meter, which is arranged on the pipe between the precooler and the precooling cold source. The pump drive module also includes a precooling on-off valve, which is arranged on the pipe between the precooler and the precooling cold source. The pump drive module also includes a condensation on-off valve, which is arranged on the two pipes between the condenser and the condensation cold source.

4. The system according to claim 1, wherein: The heating element is composed of a heating element unit and a heating element heat exchanger unit. The heating element unit corresponds to the heating element heat exchanger unit one by one. Multiple heating element units are connected in parallel. The inlet of the heating element heat exchanger unit is connected to the outlet of the preheater through a pipeline, and the outlet of the heating element heat exchanger unit is connected to the inlet of the condenser through a pipeline.

5. The system according to claim 1, wherein: A second filter is installed on the pipe connecting the liquid storage tank and the first-level low-pressure gas tank. The inlet of the second filter is connected to the top of the liquid storage tank through a pipe. The first-level pressure reducing valve is arranged on the pipe connecting the liquid storage tank and the second filter. The second-level pressure reducing valve is arranged on the pipe connecting the first-level low-pressure gas tank and the second-level low-pressure gas tank. The boosting valve is arranged on the pipe connecting the liquid storage tank and the high-pressure gas tank.

6. A method for operating a low-pressure pump-driven two-phase cooling system, characterized in that: include: When the pressure of the liquid storage tank in the pump drive module is at the rated working state, the on-off valve is opened, the boost valve, the first-stage pressure reducing valve and the second-stage pressure reducing valve are closed, and the refrigerant in the liquid storage tank flows into the first filter, then passes through the preheater, passes through the pump, the flow meter and the preheater, enters the heating element, then enters the condenser for processing, enters the reheater, and finally returns to the liquid storage tank.

7. The method according to claim 6, characterized in that Also includes: When the pressure of the liquid storage tank in the pump drive module is higher than the rated working state, the on-off valve opens, the boost valve and the secondary pressure reducing valve are closed, and the pressure reducing valve opens. The refrigerant gas in the pump drive circuit liquid storage tank flows to the first-level low-pressure gas tank in the pressure regulating module. The first-level vacuum pump is turned on intermittently according to the pressure in the first-level low-pressure gas tank. At the same time, the refrigerant in the liquid storage tank flows into the first filter, then passes through the preheater, passes through the pump, the flow meter and the preheater, enters the heating element, then enters the condenser for processing, enters the reheater, and finally returns to the liquid storage tank.

8. The method according to claim 6, characterized in that Also includes: When the pressure of the liquid storage tank in the pump drive module is higher than the rated working state, the on-off valve opens, the boost valve closes, the first-level pressure reducing valve and the second-level pressure reducing valve open, and the refrigerant gas in the liquid storage tank flows to the first-level low-pressure gas tank and the second-level low-pressure gas tank through the pipeline. The first-level vacuum pump and the second-level vacuum pump remain on. At the same time, the refrigerant in the liquid storage tank flows into the first filter, then passes through the preheater, passes through the pump, the flow meter and the preheater, enters the heating element, then enters the condenser for processing, enters the reheater, and finally returns to the liquid storage tank.

9. The method according to claim 6, characterized in that Also includes: When the pressure of the liquid storage tank in the pump drive module is lower than the rated working state, the on-off valve opens, the first-level pressure reducing valve and the second-level pressure reducing valve are closed, and the boost valve opens. The liquid storage tank obtains refrigerant gas from the high-pressure gas tank. At the same time, the refrigerant in the liquid storage tank flows into the first filter, then passes through the preheater, passes through the pump, the flow meter and the preheater, enters the heating element, then enters the condenser for processing, enters the reheater, and finally returns to the liquid storage tank.

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