A cooling and heating integrated system with defrosting function

Abstract

The present invention discloses a cold and hot integrated system with a defrosting function, comprising a compressor, a four-way reversing valve, an outdoor heat exchanger, an outdoor fan, a first one-way valve, a second one-way valve, a third one-way valve, a fourth one-way valve, a liquid storage device, a drying filter, a first throttling element, a second throttling element, an auxiliary heat exchanger, an auxiliary electric heating, an indoor heat exchanger, an indoor fan, a gas-liquid separator and a pipe system, etc., respectively forming functions such as a refrigeration cycle, a heating cycle, a defrosting cycle and a supercooling bypass under a refrigeration cycle. Compared with reverse defrosting, sensible heat defrosting, hot gas bypass defrosting and electric defrosting used in the industry, the present invention has a shorter defrosting time, lower energy consumption, and has little effect on indoor temperature fluctuations.

Description

Technical Field

[0001] The invention relates to the field of cooling and heating air conditioning systems, and in particular to a cooling and heating integrated system with a defrosting function. Background Art

[0002] As people's requirements for the protection of living environment and special cabin environment are getting higher and higher, many air conditioning equipment and environmental control equipment with various functions and forms have emerged to meet people's cooling and heating needs. Among them, when used as air source heating, the industry will pay attention to the low-temperature defrosting problem, that is, when the compressor is in heating mode, due to the influence of the external low temperature environment, the evaporator participating in the outdoor heat exchange will easily frost. As the frost becomes thicker and thicker, the heat exchange effect becomes worse and worse, and eventually the heat exchange has to be stopped and the defrosting program has to be entered. At present, professional manufacturers at home and abroad have their own defrosting methods and control procedures. Relevant colleges and researchers have also published a large number of technical papers and research reports on defrosting. The purpose is nothing more than shortening the defrosting time, reducing the impact of temperature fluctuations on the heat exchange side, improving heating efficiency and reducing energy consumption.

[0003] From the perspective of system operation of defrosting methods, there are generally 4 types: ① Reverse defrosting, that is, the equipment stops heating operation and switches to "cooling operation", and the high-temperature and high-pressure refrigerant of the compressor is transported to the outdoor heat exchanger to release heat and defrost, while the indoor heat exchanger becomes evaporative and absorbs heat. The main disadvantage is that it has a greater impact on the temperature fluctuation on the indoor side, and the defrosting time and energy consumption are not ideal; ② Sensible heat defrosting, sometimes called low-pressure hot gas defrosting, that is, the equipment stops heating operation, and the high-temperature and high-pressure refrigerant of the compressor is transported to the outdoor heat exchanger after low pressure to release heat and defrost, while the indoor heat exchanger does not have heat exchange work, which has a greater impact on the indoor temperature than reverse defrosting. The impact of temperature fluctuation is small, but the defrosting time and energy consumption are much greater than reverse defrosting. For example, the reverse defrosting time is 3 minutes, while the sensible heat defrosting time is more than 3 times, and the energy consumption is also more than 3 times; ③ Hot gas bypass defrosting, that is, the equipment does not stop heating operation, and a part of the high-temperature and high-pressure refrigerant bypasses and flows to the outdoor heat exchanger, so that the temperature rises and defrosts are performed. Its characteristic is that the indoor temperature fluctuation is between reverse defrosting and sensible heat defrosting, and the defrosting time is doubled compared with reverse defrosting; ④ Electric defrosting, one case is full electric defrosting, the energy consumption is naturally the highest, not energy-saving, and the other case is used as an auxiliary or local use. In short, the main problems of the above methods are long defrosting time and high energy consumption.

[0004] In addition, from the perspective of refrigeration, in order to improve the refrigeration efficiency of equipment, in addition to continuously improving the efficiency of components such as compressors, fans and heat exchangers, system optimization is also a way. For example, the industry is well-known for using subcoolers to increase the system's subcooling degree, thereby improving the efficiency of the entire machine. How to comprehensively apply the subcooler function used for refrigeration to heating and defrosting, and at the same time use the heat energy stored in the heating stage to accelerate the defrosting process, is worth considering. Summary of the invention

[0005] The object of the present invention is to provide a cold and hot integrated system with a defrosting function, so as to solve the problems of long defrosting time and high energy consumption in the defrosting of the cold and hot air conditioning system in the prior art.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A cold and hot integrated system with a defrosting function, characterized in that it includes a compressor, a four-way reversing valve, a gas-liquid separator, an outdoor heat exchanger, an indoor heat exchanger, first to fourth one-way valves, a liquid reservoir, a drying filter, first and second throttling elements, and an auxiliary heat exchanger with a double channel inside, wherein:

[0008] The outlet of the compressor is connected to the first valve port of the four-way reversing valve through a pipeline, the second valve port of the four-way reversing valve is connected to one end port of the outdoor heat exchanger through a pipeline, the other end port of the outdoor heat exchanger is connected to the inlet of the first one-way valve through a pipeline, the outlet of the first one-way valve is connected to the inlet of the first channel in the auxiliary heat exchanger through a pipeline, the outlet of the first channel in the auxiliary heat exchanger is connected to the inside of the liquid reservoir through a pipeline, the inside of the liquid reservoir is also connected to the inlet of the dry filter through a pipeline, the outlet of the dry filter is connected to the inlet of the first throttling element through a pipeline, the outlet of the first throttling element is connected to the inlet of the third one-way valve through a pipeline, and the outlet of the third one-way valve is connected to one end port of the indoor heat exchanger through a pipeline The other end port of the indoor heat exchanger is connected to the fourth valve port of the four-way reversing valve through a pipeline, the third valve port of the four-way reversing valve is connected to the inside of the gas-liquid separator through a pipeline, and the inside of the gas-liquid separator is also connected to the inlet of the compressor through a pipeline; the refrigerant in the compressor enters the four-way reversing valve from the first valve port of the four-way reversing valve, flows out through the second valve port of the four-way reversing valve and passes through the outdoor heat exchanger, the first one-way valve, the first channel in the auxiliary heat exchanger, the liquid storage tank, the drying filter, the first throttling element, the third one-way valve, the indoor heat exchanger in sequence, and then enters from the fourth valve port of the four-way reversing valve, and finally flows out from the third valve port of the four-way reversing valve and returns to the compressor after passing through the gas-liquid separator, thereby forming a refrigeration cycle;

[0009] The port of the indoor heat exchanger connected to the outlet of the third one-way valve is also connected to the inlet of the fourth one-way valve through a pipeline, the outlet of the fourth one-way valve is connected to the inlet of the first channel in the auxiliary heat exchanger through a pipeline, the outlet of the first throttling element is also connected to the inlet of the second one-way valve through a pipeline, and the port of the outdoor heat exchanger connected to the inlet of the first one-way valve is also connected to the outlet of the second one-way valve through a pipeline; the refrigerant in the compressor enters the four-way reversing valve from the first valve port of the four-way reversing valve, flows out through the fourth valve port of the four-way reversing valve and passes through the indoor heat exchanger, the fourth one-way valve, the first channel in the auxiliary heat exchanger, the liquid storage tank, the drying filter, the first throttling element, the second one-way valve, the outdoor heat exchanger in sequence, and then enters from the second valve port of the four-way reversing valve, and finally flows out from the third valve port of the four-way reversing valve and returns to the compressor after passing through the gas-liquid separator, thereby forming a heating cycle;

[0010] The outlet of the first one-way valve is also connected to the inlet of the second throttling element through a pipeline, the outlet of the second throttling element is connected to the inlet of the second channel in the auxiliary heat exchanger through a pipeline, and the outlet of the second channel in the auxiliary heat exchanger is connected to the inside of the gas-liquid separator through a pipeline; the refrigerant in the compressor enters the four-way reversing valve from the first valve port of the four-way reversing valve, flows out through the second valve port of the four-way reversing valve and returns to the compressor after passing through the outdoor heat exchanger, the first one-way valve, the second throttling element, the second channel in the auxiliary heat exchanger, and the gas-liquid separator in sequence, thereby forming a defrost cycle.

[0011] The integrated cold and hot system with defrost function is characterized in that: the second throttling element is in a supercooling open state in the refrigeration cycle, and the refrigerant flowing out of the first one-way valve in the refrigeration cycle bypasses through the second throttling element and enters the second channel in the auxiliary heat exchanger, and then flows out of the second channel in the auxiliary heat exchanger and returns to the compressor through the gas-liquid separator, thereby forming a supercooling bypass.

[0012] The integrated cold and hot system with defrost function is characterized in that: the first throttling element corresponds to the cooling on state and the heating on state according to the throttling and superheating requirements of the refrigeration cycle and the heating cycle respectively; the second throttling element corresponds to the subcooling on state and the defrost on state according to the throttling and superheating requirements of the subcooling bypass and the defrost cycle respectively.

[0013] The integrated cold and hot system with defrost function is characterized in that: in the defrost cycle, the outdoor heat exchanger is converted to a condenser function, the outdoor fan stops working, the auxiliary heat exchanger is converted to an evaporator function, the second throttling element is in the defrost open state, and the first throttling element is in the closed state. At this time, the indoor heat exchanger is in a non-working state, and the fan configured for the indoor heat exchanger determines whether to turn on or off based on the indoor purification conditions.

[0014] The integrated cold and hot system with defrost function is characterized in that the auxiliary heat exchanger is a dual-channel plate heat exchanger, and at least one of the three positions, namely, the outside of the auxiliary heat exchanger, the pipeline connected to the outlet of the auxiliary heat exchanger, and the gas-liquid separator, is provided with auxiliary electric heating. The auxiliary electric heating serves as a supplement to the defrost cycle to avoid the evaporation temperature being too low during the defrost cycle.

[0015] The integrated cold and hot system with defrosting function is characterized in that: the first throttling element and the second throttling element are electronic expansion valves, which are fully closed when not working; or the first throttling element and the second throttling element are both a combination structure of a thermal expansion valve and a normally closed solenoid valve to replace the electronic expansion valve.

[0016] The integrated cold and hot system with defrosting function is characterized in that the liquid reservoir has a bidirectional flow liquid storage function.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The present invention adopts this "integrated defrosting method", which can shorten the defrosting time of the equipment and reduce energy consumption, while having little impact on the temperature fluctuation on the indoor side.

[0019] 2. The present invention uses mature components. For products with supercooling function, almost no components are added, thus achieving low cost. For products without supercooling function, only a small number of components need to be added, thus achieving rapid defrosting while taking into account the improvement of refrigeration energy efficiency.

[0020] 3. The present invention has strong applicability in the field of compressor defrosting.

[0021] 4. The technical path of the present invention is clear and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0023] Explanation of the numbers in the figure: 1-compressor, 2-four-way reversing valve, 3-outdoor fan, 4-outdoor heat exchanger, 5-first one-way valve, 6-liquid reservoir, 7-drying filter, 8-first throttling element, 9-second one-way valve, 10-third one-way valve, 11-fourth one-way valve, 12-second throttling element, 13-auxiliary heat exchanger, 14-auxiliary electric heating, 15-indoor fan, 16-indoor heat exchanger, 17-gas-liquid separator. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0025] like Figure 1 As shown, Figure 1 middle Indicates the direction of refrigerant flow during the refrigeration cycle. Indicates the refrigerant flow direction during the heating cycle. Indicates the refrigerant flow direction during the defrost cycle. Indicates the refrigerant flow direction during the subcooling bypass. The present invention provides a cooling and heating integrated system with a defrosting function, comprising a compressor 1, a four-way reversing valve 2, a gas-liquid separator 17, an outdoor heat exchanger 4 equipped with an outdoor fan 3, an indoor heat exchanger 16 equipped with an indoor fan 15, and a first one-way valve 5, a second one-way valve 9, a third one-way valve 10, a fourth one-way valve 11, a liquid storage tank 6, a drying filter 7, a first throttling element 8, a second throttling element 12, and an auxiliary heat exchanger 13 with a double channel inside, wherein:

[0026] The outlet of the compressor 1 is connected to the first valve port A of the four-way reversing valve 2 through a pipeline, the second valve port B of the four-way reversing valve 2 is connected to one end port of the outdoor heat exchanger 4 through a pipeline, the other end port of the outdoor heat exchanger 4 is connected to the inlet of the first one-way valve 5 through a pipeline, the outlet of the first one-way valve 5 is connected to the inlet of the first channel in the auxiliary heat exchanger 13 through a pipeline, the outlet of the first channel in the auxiliary heat exchanger 13 is connected to the inside of the liquid reservoir 6 through a pipeline, the inside of the liquid reservoir 6 is also connected to the inlet of the dry filter 7 through a pipeline, the outlet of the dry filter 7 is connected to the inlet of the first throttling element 8 through a pipeline, the outlet of the first throttling element 8 is connected to the inlet of the third one-way valve 10 through a pipeline, the outlet of the third one-way valve 10 is connected to one end port of the indoor heat exchanger 16 through a pipeline, and the indoor The other end port of the heat exchanger 16 is connected to the fourth valve port D of the four-way reversing valve 2 through a pipeline, and the third valve port C of the four-way reversing valve 2 is connected to the inside of the gas-liquid separator 17 through a pipeline, and the inside of the gas-liquid separator 17 is also connected to the inlet of the compressor 1 through a pipeline; the refrigerant in the compressor 1 enters the four-way reversing valve 2 from the first valve port A of the four-way reversing valve 2, flows out through the second valve port B of the four-way reversing valve 2 and passes through the outdoor heat exchanger 4, the first non-return valve 5, the first channel in the auxiliary heat exchanger 13, the liquid storage tank 6, the drying filter 7, the first throttling element 8, the third non-return valve 10, and the indoor heat exchanger 16 in sequence, and then enters from the fourth valve port D of the four-way reversing valve 2, and finally flows out from the third valve port C of the four-way reversing valve 2 and returns to the compressor 1 after passing through the gas-liquid separator 17, thereby forming a refrigeration cycle;

[0027] The port of the indoor heat exchanger 16 connected to the outlet of the third one-way valve 10 is also connected to the inlet of the fourth one-way valve 11 through a pipeline, the outlet of the fourth one-way valve 11 is connected to the inlet of the first channel in the auxiliary heat exchanger 13 through a pipeline, the outlet of the first throttling element 8 is also connected to the inlet of the second one-way valve 9 through a pipeline, and the port of the outdoor heat exchanger 4 connected to the inlet of the first one-way valve 5 is also connected to the outlet of the second one-way valve 9 through a pipeline; the refrigerant in the compressor 1 is discharged from the first one-way valve 2 of the four-way reversing valve 2. Valve port A enters the four-way reversing valve 2, flows out through the fourth valve port D of the four-way reversing valve 2, and passes through the indoor heat exchanger 16, the fourth non-return valve 11, the first channel of the auxiliary heat exchanger 13, the liquid storage tank 6, the drying filter 7, the first throttling element 8, the second non-return valve 9, and the outdoor heat exchanger 4 in sequence, and then enters from the second valve port B of the four-way reversing valve 2, and finally flows out from the third valve port C of the four-way reversing valve 2 and passes through the gas-liquid separator 17 and returns to the compressor 1, thereby forming a heating cycle;

[0028] The outlet of the first one-way valve 5 is also connected to the inlet of the second throttling element 12 through a pipeline, the outlet of the second throttling element 12 is connected to the inlet of the second channel in the auxiliary heat exchanger 13 through a pipeline, and the outlet of the second channel in the auxiliary heat exchanger 13 is connected to the inside of the gas-liquid separator 17 through a pipeline; the refrigerant in the compressor 1 enters the four-way reversing valve 2 from the first valve port A of the four-way reversing valve 2, flows out through the second valve port B of the four-way reversing valve 2 and passes through the outdoor heat exchanger 4, the first one-way valve 5, the second throttling element 12, the second channel in the auxiliary heat exchanger 13, and the gas-liquid separator 17 in sequence before returning to the compressor 1, thereby forming a defrost cycle.

[0029] In the present invention, the second throttling element 12 is in a supercooling open state in the refrigeration cycle. In the refrigeration cycle, the refrigerant flowing out of the first one-way valve 5 bypasses through the second throttling element 12 and enters the second channel in the auxiliary heat exchanger 13, and then flows out of the second channel in the auxiliary heat exchanger 13 and returns to the compressor 1 through the gas-liquid separator 17, thereby forming a supercooling bypass.

[0030] In the present invention, the first throttling element 8 corresponds to the refrigeration on state and the heating on state according to the throttling and superheating requirements of the refrigeration cycle and the heating cycle respectively; the second throttling element 12 corresponds to the subcooling on state and the defrost on state according to the throttling and superheating requirements of the subcooling bypass and the defrost cycle respectively.

[0031] In the present invention, during the defrost cycle, the outdoor heat exchanger 4 is converted to a condenser function, the outdoor fan 3 stops working, the auxiliary heat exchanger 13 is converted to an evaporator function, the second throttling element 12 is in the defrost open state, and the first throttling element 8 is in the closed state. At this time, the indoor heat exchanger 16 is in a non-working state, and the indoor fan 15 configured for the indoor heat exchanger 16 determines whether to turn on or off based on the indoor purification conditions.

[0032] In the present invention, the auxiliary heat exchanger 13 is a dual-channel plate heat exchanger. An auxiliary electric heater 14 is provided at at least one of the three positions: the outside of the auxiliary heat exchanger 13, the pipeline connected to the outlet of the auxiliary heat exchanger 13, and the gas-liquid separator 17. The auxiliary electric heater 14 serves as a supplement to the defrost cycle to avoid the evaporation temperature being too low during the defrost cycle.

[0033] In the present invention, the first throttling element 8 and the second throttling element 12 are electronic expansion valves, which are fully closed when not working; or the first throttling element 8 and the second throttling element 12 are both a combination structure of a thermal expansion valve and a normally closed solenoid valve to replace the electronic expansion valve.

[0034] In the present invention, the liquid storage device 6 has a bidirectional flow liquid storage function.

[0035] The present invention can be extended to water machine products, such as air source heat pump water heaters, etc. The difference is that the indoor heat exchanger 16 is changed from a fin heat exchanger to a plate heat exchanger, a shell and tube heat exchanger, a sleeve heat exchanger, etc. In other words, the heating side is changed from air to liquid (such as water, ethylene glycol, etc.), but the working principles of heating, defrosting, etc. here can be used equivalently.

[0036] The present invention is different from reverse defrost, sensible heat defrost and hot gas bypass defrost, but it also integrates some of their advantages. For example, the refrigerant does not pass through the air-inside heat exchanger 16, and the impact on the indoor temperature fluctuation is minimal, just like the sensible heat defrost; since the heat on the evaporation side during the defrost stage mainly comes from the liquid heat energy stored in the auxiliary heat exchanger 13, and the high-temperature and high-pressure refrigerant of the compressor 1 is all transported to the outdoor heat exchanger 4 to release heat and defrost, the effect is better than the reverse defrost. Sample tests have shown that the defrost time is compressed by about 30% compared with the reverse defrost, and the energy consumption is saved by about 30%.

[0037] Due to the different environmental temperature and humidity, required functions, control parameters and procedures of the products, as well as the different selection of components such as the auxiliary heat exchanger 13, sometimes a small amount of auxiliary electric heating 14 is needed to cooperate with the completion. Or use heat pipe technology to obtain more heat from the liquid reservoir 6.

[0038] The above-described embodiments are only preferred embodiments of the present invention, but the present invention is not limited to the above-described embodiments. For a person skilled in the art, any obvious changes made thereto without departing from the principle of the present invention are within the concept of the present invention and the protection scope of the appended claims.

Claims

1. A cold and hot integrated system with defrosting function, characterized in that: The invention comprises a compressor, a four-way reversing valve, a gas-liquid separator, an outdoor heat exchanger, an indoor heat exchanger, first to fourth one-way valves, a liquid reservoir, a drying filter, a first and a second throttling element, and an auxiliary heat exchanger with double channels inside, wherein: the outlet of the compressor is connected to the first valve port of the four-way reversing valve through a pipeline, the second valve port of the four-way reversing valve is connected to one end port of the outdoor heat exchanger through a pipeline, the other end port of the outdoor heat exchanger is connected to the inlet of the first one-way valve through a pipeline, the outlet of the first one-way valve is connected to the inlet of the first channel in the auxiliary heat exchanger through a pipeline, the outlet of the first channel in the auxiliary heat exchanger is connected to the inside of the liquid reservoir through a pipeline, and the inside of the liquid reservoir is also connected to the drying filter through a pipeline. The inlet of the filter is connected, the outlet of the drying filter is connected to the inlet of the first throttling element through a pipeline, the outlet of the first throttling element is connected to the inlet of the third one-way valve through a pipeline, the outlet of the third one-way valve is connected to one end port of the indoor heat exchanger through a pipeline, the other end port of the indoor heat exchanger is connected to the fourth valve port of the four-way reversing valve through a pipeline, the third valve port of the four-way reversing valve is connected to the inside of the gas-liquid separator through a pipeline, and the inside of the gas-liquid separator is also connected to the inlet of the compressor through a pipeline; the refrigerant in the compressor enters the four-way reversing valve from the first valve port of the four-way reversing valve, flows out through the second valve port of the four-way reversing valve and passes through the outdoor heat exchanger, the first one-way valve, the first one-way valve in the auxiliary heat exchanger in sequence. The refrigerant in the compressor flows through the fourth valve port of the four-way reversing valve, flows out from the third valve port of the four-way reversing valve, passes through the gas-liquid separator, and returns to the compressor, thereby forming a refrigeration cycle; the port of the indoor heat exchanger connected to the outlet of the third one-way valve is also connected to the inlet of the fourth one-way valve through a pipeline, the outlet of the fourth one-way valve is connected to the inlet of the first channel in the auxiliary heat exchanger through a pipeline, the outlet of the first throttling element is also connected to the inlet of the second one-way valve through a pipeline, and the port of the outdoor heat exchanger connected to the inlet of the first one-way valve is also connected to the outlet of the second one-way valve through a pipeline; the refrigerant in the compressor flows from the fourth valve port of the four-way reversing valve to the inlet of the second one-way valve. A valve port enters the four-way reversing valve, flows out through the fourth valve port of the four-way reversing valve and passes through the indoor heat exchanger, the fourth one-way valve, the first channel in the auxiliary heat exchanger, the liquid storage tank, the drying filter, the first throttling element, the second one-way valve, and the outdoor heat exchanger in sequence, and then enters from the second valve port of the four-way reversing valve, and finally flows out from the third valve port of the four-way reversing valve and returns to the compressor after passing through the gas-liquid separator, thereby forming a heating cycle; the outlet of the first one-way valve is also connected to the inlet of the second throttling element through a pipeline, the outlet of the second throttling element is connected to the inlet of the second channel in the auxiliary heat exchanger through a pipeline, and the outlet of the second channel in the auxiliary heat exchanger is connected to the inside of the gas-liquid separator through a pipeline;The refrigerant in the compressor enters the four-way reversing valve from the first valve port of the four-way reversing valve, flows out through the second valve port of the four-way reversing valve, and passes through the outdoor heat exchanger, the first check valve, the second throttling element, the second channel in the auxiliary heat exchanger, and the gas-liquid separator in sequence before returning to the compressor, thus forming a defrosting cycle; The second throttling element is in a subcooling open state in the refrigeration cycle. In the refrigeration cycle, the refrigerant flowing out of the first one-way valve bypasses through the second throttling element and enters the second channel in the auxiliary heat exchanger, and then flows out of the second channel in the auxiliary heat exchanger and returns to the compressor through the gas-liquid separator, thereby forming a subcooling bypass. The first throttling element is in a cooling on state and a heating on state respectively according to the throttling and superheating requirements of the refrigeration cycle and the heating cycle; the second throttling element is in a subcooling on state and a defrosting on state respectively according to the throttling and superheating requirements of the subcooling bypass and the defrosting cycle; In the defrosting cycle, the outdoor heat exchanger is changed to the condenser function, the outdoor fan stops working, the auxiliary heat exchanger is changed to the evaporator function, the second throttling element is in the defrosting open state, the first throttling element is in the closed state, the indoor heat exchanger is in the non-working state, and the fan configured for the indoor heat exchanger is turned on or off according to the indoor purification conditions; The auxiliary heat exchanger is a dual-channel plate heat exchanger, and at least one of the three positions, the outside of the auxiliary heat exchanger, the pipeline connected to the outlet of the auxiliary heat exchanger, and the gas-liquid separator, is provided with auxiliary electric heating, which is used as a supplement to the defrost cycle to avoid the evaporation temperature being too low during the defrost cycle; The first throttling element and the second throttling element are electronic expansion valves, which are fully closed when not in operation; or the first throttling element and the second throttling element are both a combination structure of a thermal expansion valve and a normally closed electromagnetic valve to replace the electronic expansion valve; The liquid storage device has a bidirectional flow liquid storage function.

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