A fluorine pump double-cycle air conditioning system and a control method thereof

Abstract

The application discloses a fluorine pump double-cycle air conditioning system and a control method thereof. The air conditioning system comprises a compressor, a condenser, a liquid accumulator, a pump, a throttler and an evaporator which are connected in sequence through pipelines. The pipeline between the evaporator and the compressor passes through the liquid stored in the liquid accumulator. The control method adopts the air conditioning system. The air conditioning system and the control method thereof can increase the supercooling degree of the liquid in the liquid accumulator and control the superheating degree of the gas at the inlet of the compressor, thereby avoiding cavitation of the pump and liquid knock of the compressor. The whole system has simple structure, reliable operation, simple pipeline laying and convenient engineering application.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air conditioners, in particular to a fluorine pump double-cycle air conditioning system and a control method thereof. BACKGROUND

[0002] In order to maintain a low temperature in the computer room, the air conditioner needs to be started all year round to cool the load in the data center, which results in a huge power consumption and operating cost. Under the dual pressure of energy saving and emission reduction and reducing operating costs, new energy-saving technologies and new energy-saving products need to be developed for data centers.

[0003] In the transition season, there is a rich natural cold source in nature, so by using the cold source of outdoor air and delivering the cold source to the computer room after technical treatment, the temperature of the computer room can be reduced, thereby achieving the effect of energy saving and emission reduction.

[0004] The pump system (also referred to as a refrigerant pump system because the commonly used refrigerant of the air conditioning refrigeration system is freon) is an air conditioning system in which a pump is used instead of a compressor to drive the refrigerant. In summer, the special air conditioner for data centers starts the refrigeration compressor to normally refrigerate, and when the outdoor temperature is lower than the temperature preset by the controller, the controller automatically switches from the compressor refrigeration to the refrigerant pump refrigeration: the freon liquid cooled by the outdoor air-cooled condensing part is delivered to the evaporating part by the refrigerant pump, absorbs the heat in the room, and then the freon changes from liquid to gas, enters the air-cooled condensing part, and is cooled into liquid again, and the cycle continues. Since the power of the refrigerant pump is much smaller than that of the refrigeration compressor, under the same refrigeration capacity, the energy efficiency ratio of the refrigerant pump is higher than that of the refrigeration compressor, thereby achieving cooling while saving energy.

[0005] The fluid passing through the pump should be liquid, and if there is gas in the fluid passing through the pump, cavitation will occur, and the impeller surface of the pump (also referred to as a fluorine pump) will be impacted and eroded by cavitation, resulting in peeling and damage, i.e. cavitation occurs. In addition, it will also cause noise and vibration of the pump and lead to a decrease in the performance of the pump, and in severe cases, it will cause the liquid in the pump to be interrupted and unable to work normally. Therefore, before the pump system is operated, it is necessary to ensure that no gas enters the pump. Similarly, the compressor also needs to avoid the suction of liquid to prevent liquid knock.

[0006] For the current fluorine pump and compressor combined air conditioning system, in order to prevent the problems of "cavitation" and "liquid knock" of the fluorine pump and the compressor respectively when the working mode is switched, an additional electromagnetic valve needs to be arranged at the refrigerant inlet side of the fluorine pump and the compressor, and a gas-liquid separator may also need to be arranged at the inlet side of the compressor, thereby making the structure of the entire air conditioning system complex and increasing the control difficulty of the entire system. SUMMARY

[0007] The present application aims at overcoming the above-mentioned defects or problems existing in the prior art, and provides a fluorine pump double-circulation air conditioning system and a control method thereof, which can increase the subcooling degree of liquid in a liquid accumulator and control the superheating degree of gas at the inlet of a compressor, thereby avoiding cavitation of the pump and liquid hammer of the compressor without using external cold sources, and the whole system is simple in structure, reliable in operation, simple in pipeline laying and convenient in engineering application.

[0008] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0009] Technical solution one is a fluorine pump double-circulation air conditioning system, comprising a compressor, a condenser, a liquid accumulator, a pump, a throttler and an evaporator connected in sequence through pipelines, and the pipeline between the evaporator and the compressor passes through the liquid stored in the liquid accumulator.

[0010] Based on technical solution one, technical solution two is provided, in which the air conditioning system is divided into an indoor part and an outdoor part, the indoor part comprises the throttler and the evaporator, the outdoor part comprises the compressor, the condenser, the liquid accumulator and the pump, the pipeline between the evaporator and the compressor is divided into a first pipe section belonging to the indoor part and a second pipe section belonging to the outdoor part, and the second pipe section passes through the liquid stored in the liquid accumulator.

[0011] Based on technical solution two, technical solution three is provided, in which the second pipe section is provided with a cooling section extending into the liquid accumulator, the liquid accumulator is a liquid storage tank, and the cooling section is mirror-symmetric and zigzag along the height direction of the liquid storage tank.

[0012] Based on technical solution three, technical solution four is provided, in which the inlet of the liquid accumulator is higher than the outlet thereof.

[0013] Based on technical solution four, technical solution five is provided, which further comprises a first control valve and a second control valve, the first control valve is connected in parallel through a pipeline between the input end and the output end of the compressor, and the second control valve is connected in parallel through a pipeline between the input end of the liquid accumulator and the output end of the pump.

[0014] Sixth, the present application provides a kind of fluorine pump double cycle air conditioning system control method, it uses the air conditioning system described in technical solution five, the control method includes: obtaining outdoor temperature Tout, indoor temperature Tin And refrigeration demand, obtain first set value T1;If Tin-Tout <T1 And refrigeration demand is greater than 100%, then with first refrigeration mode operation;If Tin-Tout ≥T1 And refrigeration demand is greater than or equal to 100%, then with second refrigeration mode operation;If Tin-Tout ≥T1 And refrigeration demand is greater than 30% and less than 100%, then with third refrigeration mode operation;In the first refrigeration mode, the compressor is opened and is formed refrigeration cycle with condenser and evaporator, and the refrigerant pump is closed;In the second refrigeration mode, the compressor and refrigerant pump are all opened and are formed refrigeration cycle with condenser and evaporator;In the third refrigeration mode, the compressor is closed, and the refrigerant pump is opened and is formed refrigeration cycle with condenser and evaporator.

[0015] Based on technical solution six, there is also technical solution seven, in technical solution seven, obtaining the refrigeration demand includes the following steps: obtaining indoor target temperature Tset and second set value T2, and the refrigeration demand is (Tin-Tset) / T2*100%.

[0016] Eighth, the present application simultaneously provides a kind of fluorine pump double cycle air conditioning system control method, it uses the air conditioning system described in technical solution five, the control method includes: obtaining outdoor temperature Tout, according to the relationship of Tout With first set value T1 And second set value T2 Determine the refrigeration mode of operation, if Tout >T1, then determine with first refrigeration mode operation;If T2 <Tout ≤T1, then determine with second refrigeration mode operation;If Tout ≤2, then determine with third refrigeration mode operation;According to the relationship of outdoor temperature Tout With first set value T1, Second set value T2 And third set value Δt and the refrigeration mode of operation currently adjusts the refrigeration mode of operation;If current is first refrigeration mode: if T2 <Tout ≤T1-△t, then switch to second refrigeration mode;If current is second refrigeration mode: if Tout ≥T1 +△t, then switch to first refrigeration mode;If Tout ≤T2-△t, then switch to third refrigeration mode;If current is third refrigeration mode: if T2 +△t ≤Tout ≤T1, then switch to second refrigeration mode;In the first refrigeration mode, the compressor is opened and is formed refrigeration cycle with condenser and evaporator, and the refrigerant pump is closed;In the second refrigeration mode, the compressor and refrigerant pump are all opened and are formed refrigeration cycle with condenser and evaporator;In the third refrigeration mode, the compressor is closed, and the refrigerant pump is opened and is formed refrigeration cycle with condenser and evaporator.

[0017] From the above description of the present application, relative to the prior art, the present application has the following beneficial effects:

[0018] 1、In technical solution one, the condenser dissipates the heat of the high-temperature and high-pressure gas delivered by the compressor into low-temperature and high-pressure liquid, the throttling device makes the low-temperature and high-pressure liquid pass through throttling to become low-temperature and low-pressure wet steam, the evaporator evaporates the wet steam into gas, and the compressor compresses the gas into high-temperature and high-pressure gas to form a refrigeration cycle. It can be seen that, due to the presence of the throttling device, the temperature of the gas at the output end of the evaporator is lower than the temperature of the liquid in the liquid accumulator, the pipeline between the evaporator and the compressor passes through the liquid stored in the liquid accumulator, can exchange heat with the liquid in the liquid accumulator, thereby increasing the subcooling degree of the liquid in the liquid accumulator, ensuring that the pump sucks in liquid refrigerant rather than gaseous liquid refrigerant during the starting of the pump or the switching of the refrigeration mode, preventing the pump from cavitation, thereby protecting the pump, and the temperature of the pipeline between the evaporator and the compressor increases after passing through the liquid stored in the liquid accumulator, which can better control the superheat degree of the suction gas of the compressor, thereby preventing the problem of liquid hammering of the compressor due to the suction of liquid refrigerant, improving the stability and reliability of the entire air conditioning system. In addition, in this technical solution, the subcooling degree of the liquid in the liquid accumulator and the superheat degree of the gas at the inlet of the compressor can be increased by making the pipeline between the evaporator and the compressor pass through the liquid stored in the liquid accumulator, without borrowing an external cold source. The entire system has a simple structure, is more reliable in operation, has simple pipeline laying, and is more convenient for engineering application.

[0019] 2、In technical solution two, the pipeline between the evaporator and the compressor is divided into a first pipe section belonging to the indoor part and a second pipe section belonging to the outdoor part; the second pipe section passes through the liquid stored in the liquid accumulator. This design is more convenient when the pipeline is connected, and the overall pipeline length is shorter.

[0020] 3、In technical solution three, the structure of the cooling section is provided with a large heat exchange area, which is conducive to reducing the temperature of the liquid in the liquid accumulator, thereby increasing the subcooling degree of the liquid in the liquid accumulator.

[0021] 4、In technical solution four, the inlet of the liquid accumulator is higher than the outlet thereof, which further prevents gas from entering the pump.

[0022] 5、In technical solution five, the first control valve and the second control valve are provided, which is conducive to making the air conditioning system operate in different refrigeration modes, and is more energy-saving and environmentally friendly.

[0023] 6、In technical solution six, the present application simultaneously provides a control method of a fluorine pump double-circulation air conditioning system, which adopts the air conditioning system of technical solution five and has the same advantages as described above. In this technical solution, the refrigeration mode is adjusted according to the indoor-outdoor temperature difference and the refrigeration demand, which is more in line with the actual use, thereby ensuring that the air conditioning system can always meet the refrigeration demand and ensuring the stable operation of the indoor working condition.

[0024] 7、Technical solution seven, the refrigeration demand is determined by the target temperature and the indoor temperature, which is more in line with the actual use.

[0025] 8、Technical solution eight, the application also provides a control method of the fluorine pump double-cycle air conditioning system, which adopts the air conditioning system of technical solution five, has the same advantages as above; and in this solution, when the first refrigeration mode is switched to the second refrigeration mode, the outdoor temperature needs to be less than or equal to T1-△t, when the second refrigeration mode is switched to the first refrigeration mode, the outdoor temperature needs to be greater than or equal to T1+△t, avoiding frequent switching between the first refrigeration mode and the second refrigeration mode; when the second refrigeration mode is switched to the third refrigeration mode, the outdoor temperature needs to be less than or equal to T2-△t, when the third refrigeration mode is switched to the second refrigeration mode, the outdoor temperature needs to be greater than or equal to T2+△t, avoiding frequent switching between the second refrigeration mode and the third refrigeration mode, thereby avoiding frequent start and stop of the pump or compressor, and avoiding unstable indoor working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following briefly introduces the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 It is a schematic diagram of the air conditioning system of embodiment 1 of the application.

[0028] Main figure mark explanation:

[0029] Compressor 10; condenser 20; liquid accumulator 30; pump 40; throttling device 50; evaporator 60; first control valve 70; second control valve 80; first branch 01; second branch 02; first pipe section 03; second pipe section 04; cooling section 041; indoor part 100. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are preferred embodiments of the application, and should not be regarded as exclusion of other embodiments. Based on the embodiments of the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0031] In the claims, specification and above drawings of the application, unless otherwise explicitly limited, the terms such as "first", "second" or "third" are used only to distinguish different objects, and are not used to describe a specific order.

[0032] In the claims, the specification, and the drawings of the present application, terms such as "center", "transverse", "longitudinal", "horizontal", "vertical", "top", "bottom", "inner", "outer", "upper", "lower", "front", "rear", "left", "right", "clockwise", "counterclockwise", etc. are used as terms of reference and are not intended to limit the specific orientation or configuration of the apparatus or elements thereof, unless otherwise specifically indicated. Therefore, these terms are used merely to simplify the description of the application and are not intended to limit the specific protection scope of the application.

[0033] In the claims, the specification, and the drawings of the present application, unless otherwise specifically indicated, the term "fixedly connected" or "fixedly connected" should be understood in a broad sense, that is, any connection mode between the two without displacement relationship and relative rotation relationship, that is, it includes non-detachable fixed connection, detachable fixed connection, integration and fixed connection through other devices or elements.

[0034] In the claims, the specification, and the drawings of the present application, the terms "include", "have" and their variants are intended to mean "include but not limited to".

[0035] Reference is made to Figure 1 , Figure 1 A fluorine pump double-circuit air conditioning system is shown, which includes a compressor 10, a condenser 20, a liquid accumulator 30, a pump 40, a throttling device 50, an evaporator 60, a first control valve 70 and a second control valve 80.

[0036] The compressor 10, the condenser 20, the liquid accumulator 30, the pump 40, the throttling device 50 and the evaporator 60 are connected in series by pipelines, the first control valve 70 is connected in parallel by pipelines between the input end and the output end of the compressor 10 to form a first branch 01, and the second control valve 80 is connected in parallel by pipelines between the input end of the liquid accumulator 30 and the output end of the pump 40 to form a second branch 02. In this embodiment, the first control valve 70 and the second control valve 80 are both one-way valves, and the throttling device 50 is an electronic expansion valve.

[0037] The air conditioning system is divided into an indoor part 100 and an outdoor part (other than the indoor part 100), the indoor part 100 includes the throttling device 50 and the evaporator 60, and the outdoor part includes the compressor 10, the condenser 20, the liquid accumulator 30 and the pump 40; the pipeline between the evaporator 60 and the compressor 10 is divided into a first pipe section 03 belonging to the indoor part 100 and a second pipe section 04 belonging to the outdoor part.

[0038] The embodiment avoids the occurrence of cavitation and liquid hammer mainly through pipeline design. Specifically, the pipeline between the evaporator 60 and the compressor 10 passes through the liquid stored in the liquid accumulator 30. In the embodiment, the second pipe section 04 passes through the liquid stored in the liquid accumulator 30.

[0039] Specifically, the second pipe section 04 is provided with a cooling section 041 extending into the liquid accumulator 30. The liquid accumulator 30 is a liquid storage tank, and the cooling section 041 is mirror-symmetrical and zigzag along the height direction of the liquid storage tank.

[0040] The inlet of the liquid accumulator 30 is higher than the outlet, further avoiding the gas entering the pump 40.

[0041] In actual application, the air conditioning system further includes a controller electrically connected with and controlling the first control valve 70, the second control valve 80, the compressor 10, the pump 40, the condenser 20, the throttling device 50 and the evaporator 60.

[0042] Based on the above air conditioning system, the air conditioning system of the embodiment can operate three refrigeration modes, namely a first refrigeration mode, a second refrigeration mode and a third refrigeration mode.

[0043] In the first refrigeration mode, the first control valve 70 is closed, the second control valve 80 is opened, the throttling device 50 is opened, the pump 40 is closed, the compressor 10 is opened and forms a refrigeration cycle with the condenser 20 and the evaporator 60. Specifically, the compressor 10 highly compresses the refrigerant circulating from the evaporator 60, compresses the gaseous refrigerant into a high-temperature and high-pressure state and sends it to the condenser 20 to condense into refrigerant liquid at a low temperature and high pressure. The refrigerant liquid flows to the evaporator 60 through the second branch 02 and the throttling device 50. The liquid refrigerant is evaporated by the evaporator 60 and enters the compressor 10 in sequence through the first pipe section 03 and the second pipe section 04, completing a refrigeration cycle.

[0044] In the second refrigeration mode, the first control valve 70 and the second control valve 80 are both closed, the throttling device 50 is opened, and the compressor 10 and the pump 40 are both opened and form a refrigeration cycle with the condenser 20 and the evaporator 60. Specifically, the refrigerant comes out of the compressor 10, enters the condenser 20 to condense into refrigerant liquid, and the refrigerant liquid flows to the evaporator 60 through the liquid storage tank, the pump 40 and the throttling device 50. The liquid refrigerant is evaporated by the evaporator 60 and enters the compressor 10 in sequence through the first pipe section 03 and the second pipe section 04, completing a refrigeration cycle.

[0045] In the third refrigeration mode, the first control valve 70 and the throttle 50 are both open, the second control valve 80 is closed, the compressor 10 is closed, and the pump 40 forms a refrigeration cycle with the condenser 20 and the evaporator 60. Specifically, after the refrigerant exits the evaporator 60, it enters the condenser 20 through the first branch 0 to be condensed into a refrigerant liquid. The refrigerant liquid then flows through the liquid receiver >30, the pump 40, and the throttle 50 to the evaporator 60. The liquid refrigerant absorbs heat and evaporates in the evaporator 60 and then enters the compressor 10 through the first pipe section 03 and the second pipe section 04 in sequence, completing a refrigeration cycle.

[0046] It can be seen that due to the presence of the throttle 50, the gas temperature at the output end of the evaporator 60 is lower than the temperature of the liquid in the liquid receiver 30. The pipeline between the evaporator 60 and the compressor 10 passes through the liquid stored in the liquid receiver 30, especially the second pipe section 04 outdoors passes through the liquid stored in the liquid receiver 30. This design is more convenient for pipeline connection, and the overall pipeline length is shorter. The cooling section 041 of the second pipe section 04 extends into the liquid receiver 30, and the cooling section 041 can exchange heat with the liquid in the liquid receiver 30 to increase the subcooling degree of the liquid in the liquid receiver 30. The structure of the cooling section 041 has a large heat exchange area, which is beneficial to reducing the temperature of the liquid in the liquid receiver 30, thereby increasing the subcooling degree of the liquid in the liquid receiver 30. In this way, it is ensured that during the start-up of the pump 40 or the switching of the refrigeration mode, the pump 40 sucks in liquid refrigerant instead of gaseous refrigerant, preventing cavitation of the pump 40, thereby protecting the pump 40. Moreover, the temperature of the pipeline between the evaporator 60 and the compressor 10 increases after passing through the liquid stored in the liquid receiver 30, which can better control the suction superheat degree of the compressor 10, thereby preventing the problem of liquid slugging of the compressor 10 due to sucking in liquid refrigerant, and improving the stability and reliability of the entire air-conditioning system. In addition, in this technical solution, by making the pipeline between the evaporator 60 and the compressor 10 pass through the liquid stored in the liquid receiver 30, the subcooling degree of the liquid in the liquid receiver 30 can be increased and the superheat degree of the gas at the inlet of the compressor 10 can be controlled, without borrowing an external cold source. The entire system has a simple structure, more reliable system operation, simple pipeline laying, and more convenient engineering application.

[0047] Embodiment 2

[0048] The present invention provides a control method for a control system, which uses the air-conditioning system of Embodiment 1. The control method includes:

[0049] Obtain the outdoor temperature Tout, the indoor temperature Tin, the first set value T1, and the refrigeration demand; obtaining the refrigeration demand includes the following steps: obtaining the indoor target temperature Tset and the second set value T2, and the refrigeration demand is (Tin - Tset) / T2 * 100%.

[0050] If Tin - Tout < T1 and the refrigeration demand is greater than 100%, then operate in the first refrigeration mode;

[0051] If Tin-Tout≥T1 and the refrigeration demand is greater than or equal to 100%, the second refrigeration mode is run;

[0052] If Tin-Tout≥T1 and the refrigeration demand is greater than 30% and less than 100%, the third refrigeration mode is run.

[0053] In the specific implementation, the temperature sensor can be arranged to collect the outdoor temperature and the indoor temperature, which belongs to the prior art, and the present embodiment will not be described in detail. In actual application, T1 is generally 20℃, and T2 is generally 3℃.

[0054] The control method of the present embodiment has the same advantages as the air conditioning system of embodiment 1. In the technical solution, the refrigeration mode is adjusted according to the indoor and outdoor temperature difference and the refrigeration demand, which is more in line with the actual use, so as to ensure that the air conditioning system can always meet the refrigeration demand and ensure the stable operation of the indoor working condition.

[0055] Embodiment 3

[0056] The present application provides a control method of a control system, which adopts the air conditioning system of embodiment 1, and the control method comprises:

[0057] The outdoor temperature Tout is obtained, and the running refrigeration mode is determined according to the relationship between Tout and the first set value T1 and the second set value T2. If Tout>T1, it is determined that the first refrigeration mode is run. If T2<Tout≤T1, it is determined that the second refrigeration mode is run. If Tout≤T2, it is determined that the third refrigeration mode is run.

[0058] The running refrigeration mode is adjusted according to the relationship between the outdoor temperature Tout and the first set value T1, the second set value T2 and the third set value Δt and the current running refrigeration mode.

[0059] If the current is the first refrigeration mode: if T2<Tout≤T1-Δt, it is switched to the second refrigeration mode.

[0060] If the current is the second refrigeration mode: if Tout≥T1+Δt, it is switched to the first refrigeration mode; if Tout≤T2-Δt, it is switched to the third refrigeration mode.

[0061] If the current is the third refrigeration mode: if T2+Δt≤Tout≤T1, it is switched to the second refrigeration mode.

[0062] In the specific implementation, the temperature sensor can be arranged to collect the outdoor temperature, the first set value is generally 15℃, and the second set value is generally 5℃. The third set value Δt can be set according to the measured temperature curve. In the present embodiment, Δt is 2-3℃.

[0063] The control method of the embodiment has the same advantages as the air conditioning system of Embodiment 1. In the embodiment, the outdoor temperature needs to be less than or equal to T1-△t when switching from the first refrigeration mode to the second refrigeration mode, and the outdoor temperature needs to be greater than or equal to T1+△t when switching from the second refrigeration mode to the first refrigeration mode, thereby avoiding frequent switching between the first refrigeration mode and the second refrigeration mode. The outdoor temperature needs to be less than or equal to T2-△t when switching from the second refrigeration mode to the third refrigeration mode, and the outdoor temperature needs to be greater than or equal to T2+△t when switching from the third refrigeration mode to the second refrigeration mode, thereby avoiding frequent switching between the second refrigeration mode and the third refrigeration mode, avoiding frequent starting and stopping of the pump 40 or the compressor 10, and avoiding unstable indoor working conditions.

[0064] The above description and the embodiments are used to explain the scope of protection of the present application, but do not constitute a limitation on the scope of protection of the present application. Through the inspiration of the present application or the above embodiments, those skilled in the art can obtain the modification, equivalent replacement or other improvement of the embodiments of the present application or one part of the technical features by combining the common knowledge, the ordinary technical knowledge in the art and / or the prior art, through logical analysis, reasoning or limited experiments, which should be included in the scope of protection of the present application.

Claims

1. A fluorine pump double cycle air conditioning system comprising a compressor (10), a condenser (20), a liquid accumulator (30), a pump (40), a throttling device (50) and an evaporator (60) connected in series through pipes, characterized in that, The pipeline between the evaporator (60) and the compressor (10) passes through the liquid stored in the liquid accumulator (30), the pipeline between the evaporator (60) and the compressor (10) is provided with a cooling section (041) extending into the liquid accumulator (30), the liquid accumulator (30) is a liquid storage tank, and the cooling section (041) is mirror-symmetrical; further comprising a first control valve (70) and a second control valve (80), the first control valve (70) is connected in parallel between the input end and the output end of the compressor (10) through a pipeline, and the second control valve (80) is connected in parallel between the input end of the liquid accumulator (30) and the output end of the pump (40) through a pipeline.

2. The air conditioning system of claim 1, wherein, The air conditioning system is divided into an indoor part (100) and an outdoor part, the indoor part (100) comprises the throttler (50) and the evaporator (60), and the outdoor part comprises the compressor (10), the condenser (20), the liquid accumulator (30) and the pump (40); the pipeline between the evaporator (60) and the compressor (10) is divided into a first pipe section (03) belonging to the indoor part (100) and a second pipe section (04) belonging to the outdoor part; the second pipe section (04) passes through the liquid stored in the liquid accumulator (30), and the second pipe section (04) is provided with the cooling section (041).

3. A fluoro-pump dual-cycle air conditioning system as set forth in claim 2, characterized in that, The cooling section (041) is zigzag-shaped along the height direction of the liquid storage tank.

4. A fluoro-pump dual-cycle air conditioning system as set forth in claim 3, characterized in that, The inlet of the liquid accumulator (30) is higher than the outlet.

5. A control method of a fluorine pump dual cycle air conditioning system, characterized by, The control method comprises: obtaining an outdoor temperature Tout, an indoor temperature Tin and a refrigeration demand, obtaining a first set value T1; if Tin-Tout < T1 and the refrigeration demand is greater than 100%, operating in a first refrigeration mode; if Tin-Tout ≥ T1 and the refrigeration demand is greater than or equal to 100%, operating in a second refrigeration mode; if Tin-Tout ≥ T1 and the refrigeration demand is greater than 30% and less than 100%, operating in a third refrigeration mode; in the first refrigeration mode, the compressor (10) is turned on and forms a refrigeration cycle with the condenser (20) and the evaporator (60), and the refrigerant pump (40) is turned off; in the second refrigeration mode, the compressor (10) and the refrigerant pump (40) are both turned on and form a refrigeration cycle with the condenser (20) and the evaporator (60); in the third refrigeration mode, the compressor (10) is turned off, the refrigerant pump (40) is turned on and forms a refrigeration cycle with the condenser (20) and the evaporator (60).

6. The control method of a fluoro-pump dual cycle air conditioning system according to claim 5, wherein, The step of obtaining the refrigeration demand comprises the following steps: obtaining an indoor target temperature Tset and a second set value T2, and the refrigeration demand is (Tin-Tset) / T2*100%.

7. A control method of a fluorine pump dual cycle air conditioning system, characterized by, The control method comprises: An outdoor temperature Tout is acquired, and a running refrigeration mode is determined according to a relationship of Tout with a first set value T1 and a second set value T2, wherein if Tout>T1, the first refrigeration mode is determined to run; if T2 The running refrigeration mode is adjusted according to a relationship of an outdoor temperature Tout with a first set value T1, a second set value T2, a third set value Δt and a current running refrigeration mode; If the current running refrigeration mode is the first refrigeration mode, if T2 If the current running refrigeration mode is the second refrigeration mode, if Tout≥T1+Δt, the first refrigeration mode is switched to; if Tout≤T2-Δt, the third refrigeration mode is switched to; If the current running refrigeration mode is the third refrigeration mode, if T2+Δt≤Tout≤T1, the second refrigeration mode is switched to; In the first refrigeration mode, the compressor (10) is started and forms a refrigeration cycle with the condenser (20) and the evaporator (60), and the refrigerant pump (40) is stopped; In the second refrigeration mode, the compressor (10) and the refrigerant pump (40) are both started and form a refrigeration cycle with the condenser (20) and the evaporator (60); In the third refrigeration mode, the compressor (10) is stopped, the refrigerant pump (40) is started and forms a refrigeration cycle with the condenser (20) and the evaporator (60).

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