Low-temperature air source heat pump system

Abstract

The utility model provides a low-temperature air source heat pump system, and relates to the technical field of heat pumps. The low-temperature air source heat pump system comprises a compressor, a fluorine pump, a finned tube heat exchanger, a gas-liquid separator, a circulation pipeline, a first parallel connection pipeline and a second parallel connection pipeline, the compressor and the gas-liquid separator are arranged on the first parallel connection pipeline, and the fluorine pump is arranged on the second parallel connection pipeline. The finned tube heat exchanger is arranged on the circulating pipeline; two ends of the first parallel pipeline are respectively connected with the circulating pipeline, two ends of the second parallel pipeline are respectively connected with the circulating pipeline, and the first parallel pipeline is connected with the second parallel pipeline in parallel. According to the low-temperature air source heat pump system, when the environment temperature is low, the fluorine pump conducts defrosting, the compressor does not work, and the risk that the compressor is damaged is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of heat pumps, and in particular to a low-temperature air source heat pump system. Background Art

[0002] Existing low-temperature air source heat pump systems generally include structures such as a compressor and a fin-tube heat exchanger. When the low-temperature air source heat pump system is used for cooling, heating or defrosting, the refrigerant circulation in the low-temperature air source heat pump system is driven by the compressor.

[0003] However, when the low-temperature air source heat pump system is performing winter heating and defrosting, the low-temperature air source heat pump system has a greater risk of liquid backflow and oil shortage, which increases the risk of compressor damage and further affects the service life of the low-temperature air source heat pump system. Utility Model Content

[0004] In view of this, the present application provides a low-temperature air source heat pump system to solve the problem that the low-temperature air source heat pump system has a high risk of liquid backflow and oil shortage when performing winter heating and defrosting, which increases the risk of damage and thus affects the service life of the low-temperature air source heat pump system.

[0005] The present application provides a low-temperature air source heat pump system, which includes a compressor, a fluorine pump, a fin-tube heat exchanger, a gas-liquid separator, a circulation pipeline, a first parallel pipeline and a second parallel pipeline, wherein the compressor and the gas-liquid separator are arranged on the first parallel pipeline, the fluorine pump is arranged on the second parallel pipeline, and the fin-tube heat exchanger is arranged on the circulation pipeline;

[0006] Both ends of the first parallel pipeline are connected to the circulation pipeline respectively, and both ends of the second parallel pipeline are connected to the circulation pipeline respectively. The first parallel pipeline and the second parallel pipeline are connected in parallel.

[0007] Preferably, the low-temperature air source heat pump system further comprises a four-way valve, the circulation pipeline comprises a first connecting pipe, a second connecting pipe, a third connecting pipe and a fourth connecting pipe, the first connecting pipe, the second connecting pipe, the third connecting pipe and the fourth connecting pipe are all connected to the four-way valve, the second connecting pipe is connected to one of the first connecting pipe and the third connecting pipe, and the fourth connecting pipe is connected to the other of the first connecting pipe and the third connecting pipe;

[0008] The first end of the first parallel pipeline and the first end of the second parallel pipeline are both connected to the first connecting pipeline, the second end of the first parallel pipeline and the second end of the second parallel pipeline are both connected to the third connecting pipeline, the second connecting pipeline is connected to the fourth connecting pipeline, and the fin-tube heat exchanger is arranged on the second connecting pipeline.

[0009] Preferably, the low-temperature air source heat pump system further includes an economizer, the economizer includes a first connecting port and a second connecting port, the first connecting port is connected to the second connecting pipe, and the second connecting port is connected to the fourth connecting pipe.

[0010] Preferably, the economizer further includes a third connecting port and a fourth connecting port, and the circulation pipeline further includes a first adapter pipe and a second adapter pipe, one end of the first adapter pipe is connected to the second connecting pipe, the other end of the first adapter pipe is connected to the third connecting port, one end of the second adapter pipe is connected to the fourth connecting port, and the other end of the second adapter pipe is connected to the compressor.

[0011] Preferably, the low-temperature air source heat pump system further comprises a plate heat exchanger, and the plate heat exchanger comprises a first adapter and a second adapter;

[0012] The circulation pipeline also includes a connecting pipe, the second connecting port and the first adapter are connected through the connecting pipe, one end of the fourth connecting pipe is connected to the second adapter, and the other end of the fourth connecting pipe is connected to the four-way valve.

[0013] Preferably, the low-temperature air source heat pump system further comprises a liquid storage tank, and the liquid storage tank is arranged on the connecting pipe.

[0014] Preferably, the low-temperature air source heat pump system further includes a first electronic expansion valve and a second electronic expansion valve, wherein the first electronic expansion valve is arranged on the second connecting pipe, and the second electronic expansion valve is arranged on the first transfer pipe.

[0015] Preferably, the low-temperature air source heat pump system further includes a first solenoid valve, and the first solenoid valve is arranged on the second adapter pipe.

[0016] Preferably, the low-temperature air source heat pump system further includes a second solenoid valve and a third solenoid valve, the second solenoid valve and the third solenoid valve are both arranged on the first parallel pipeline, and the compressor and the gas-liquid separator are located between the second solenoid valve and the third solenoid valve.

[0017] Preferably, the low-temperature air source heat pump system further includes a fourth solenoid valve and a fifth solenoid valve, both of which are arranged on the second parallel pipeline, and the fluorine pump is located between the fourth solenoid valve and the fifth solenoid valve.

[0018] When the low-temperature air source heat pump system of the present application is defrosted, when the ambient temperature is high, a compressor can be used for defrosting. At this time, the compressor works and the fluorine pump does not work. The compressor compresses the gaseous low-temperature and low-pressure refrigerant into a high-temperature and high-pressure gas, and then the refrigerant enters the fin tube heat exchanger. The refrigerant releases heat in the fin tube heat exchanger and condenses into a medium-temperature and high-pressure liquid and absorbs heat in the process to defrost the surface of the fin tube heat exchanger, and then returns to the compressor through the circulation pipeline, thereby completing a defrosting cycle. When the ambient temperature is low, a fluorine pump can be used for defrosting. At this time, the fluorine pump works and the compressor does not work. The fluorine pump transports the liquid refrigerant to the fin tube heat exchanger, and the liquid refrigerant exchanges heat with the fin tube heat exchanger, so that the frost layer on the surface of the fin tube heat exchanger melts, and then the liquid refrigerant returns to the fluorine pump through the circulation pipeline, thereby completing a defrosting cycle. In this way, when the ambient temperature is low, the fluorine pump defrosts and the compressor does not work, which reduces the risk of compressor damage and improves the service life of the low-temperature air source heat pump system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic structural diagram showing a low-temperature air source heat pump system according to an embodiment of the utility model;

[0021] Figure 2 A schematic diagram showing the refrigerant flow direction when the low-temperature air source heat pump system of an embodiment of the utility model is in a heating mode;

[0022] Figure 3 A schematic diagram showing the refrigerant flow direction when the low-temperature air source heat pump system of an embodiment of the utility model is in a cooling mode;

[0023] Figure 4 A schematic diagram showing the refrigerant flow direction when the low-temperature air source heat pump system of an embodiment of the utility model is in the first defrosting mode;

[0024] Figure 5 A schematic diagram showing the refrigerant flow direction when the low-temperature air source heat pump system of an embodiment of the utility model is in the second defrost mode.

[0025] Icons: 1- compressor; 2- fluorine pump; 31- fin-tube heat exchanger; 32- gas-liquid separator; 33- economizer; 331- first connection port; 332- second connection port; 333- third connection port; 334- fourth connection port; 34- plate heat exchanger; 341- first adapter; 342- second adapter; 343- third adapter; 344- fourth adapter; 35- liquid storage tank; 4- four-way valve; 51- first electronic expansion valve; 52- second electronic expansion valve; 61- first solenoid valve; 62- second solenoid valve; 63- third solenoid valve; 64- fourth solenoid valve; 65- fifth solenoid valve; 71- first parallel pipeline; 72- second parallel pipeline; 81- first connecting pipeline; 82- second connecting pipeline; 83- third connecting pipeline; 84- fourth connecting pipeline; 91- first transfer pipeline; 92- second transfer pipeline; 93- connecting pipeline. DETAILED DESCRIPTION

[0026] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0027] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0028] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0029] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0030] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0031] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0032] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0033] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0034] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0035] The present application provides a low temperature air source heat pump system, such as Figure 1 As shown, the low-temperature air source heat pump system includes a compressor 1, a fluorine pump 2, a fin-tube heat exchanger 31, a gas-liquid separator 32, a circulation pipeline, a first parallel pipeline 71 and a second parallel pipeline 72. The compressor 1 and the gas-liquid separator 32 are arranged on the first parallel pipeline 71, the fluorine pump 2 is arranged on the second parallel pipeline 72, and the fin-tube heat exchanger 31 is arranged on the circulation pipeline; both ends of the first parallel pipeline 71 are respectively connected to the circulation pipeline, and both ends of the second parallel pipeline 72 are respectively connected to the circulation pipeline, and the first parallel pipeline 71 and the second parallel pipeline 72 are connected in parallel. When the low-temperature air source heat pump system of the present application is defrosted, when the ambient temperature is high, compressor 1 can be used for defrosting. At this time, compressor 1 works and fluorine pump 2 does not work. Compressor 1 compresses the gaseous low-temperature and low-pressure refrigerant into a high-temperature and high-pressure gas, and then the refrigerant enters the fin-tube heat exchanger 31. The refrigerant releases heat in the fin-tube heat exchanger 31 and condenses into a medium-temperature and high-pressure liquid. In the process, the refrigerant absorbs heat to defrost the surface of the fin-tube heat exchanger 31, and then returns to compressor 1 through the circulation pipeline, thereby completing a defrosting cycle. When the ambient temperature is low, fluorine pump 2 can be used for defrosting. At this time, fluorine pump 2 works and compressor 1 does not work. Fluorine pump 2 transports liquid refrigerant to fin-tube heat exchanger 31. The liquid refrigerant exchanges heat with fin-tube heat exchanger 31, so that the frost layer on the surface of fin-tube heat exchanger 31 melts, and then the liquid refrigerant returns to fluorine pump 2 through the circulation pipeline, thereby completing a defrosting cycle. In this way, when the ambient temperature is low, the fluorine pump 2 is defrosted and the compressor 1 does not work, which reduces the risk of damage to the compressor 1 and increases the service life of the low-temperature air source heat pump system.

[0036] In addition, when the temperature is high, the low-temperature air source heat pump system uses compressor 1 to defrost the fin-tube heat exchanger 31, which can ensure the defrosting efficiency of the fin-tube heat exchanger 31. When the temperature is low, the low-temperature air source heat pump system uses fluorine pump 2 to defrost the fin-tube heat exchanger 31, and no longer uses compressor 1 to defrost the fin-tube heat exchanger 31, reducing the risk of damage to compressor 1. In this way, the low-temperature air source heat pump system of the present application can take into account both defrosting efficiency and safety during operation during defrosting, ensuring the reliability of the operation of the low-temperature air source heat pump system.

[0037] In the embodiments of the present application, Figure 1As shown, the low-temperature air source heat pump system further includes a four-way valve 4, and the circulation pipeline includes a first connecting pipeline 81, a second connecting pipeline 82, a third connecting pipeline 83 and a fourth connecting pipeline 84. The first connecting pipeline 81, the second connecting pipeline 82, the third connecting pipeline 83 and the fourth connecting pipeline 84 are all connected to the four-way valve 4, the second connecting pipeline 82 is connected to one of the first connecting pipeline 81 and the third connecting pipeline 83, and the fourth connecting pipeline 84 is connected to the other of the first connecting pipeline 81 and the third connecting pipeline 83. The first end of the first parallel pipeline 71 and the first end of the second parallel pipeline 72 are both connected to the first connecting pipeline 81, the second end of the first parallel pipeline 71 and the second end of the second parallel pipeline 72 are both connected to the third connecting pipeline 83, the second connecting pipeline 82 is connected to the fourth connecting pipeline 84, and the fin-tube heat exchanger 31 is arranged on the second connecting pipeline 82. By reversing the four-way valve 4, the connection states of the first connecting pipe 81, the second connecting pipe 82, the third connecting pipe 83 and the fourth connecting pipe 84 can be switched, thereby switching between the cooling mode, the heating mode and the defrosting mode. When the low-temperature air source heat pump system is in the heating mode, the first connecting pipe 81 is connected to the fourth connecting pipe 84, and the second connecting pipe 82 is connected to the third connecting pipe 83; when the low-temperature air source heat pump system is in the cooling mode, the first defrosting mode and the second defrosting mode, the first connecting pipe 81 is connected to the second connecting pipe 82, and the third connecting pipe 83 is connected to the fourth connecting pipe 84. In this way, by reversing the four-way valve 4, the flow of refrigerant in different modes can be achieved.

[0038] Further, the low-temperature air source heat pump system also includes a second solenoid valve 62 and a third solenoid valve 63, both of which are arranged on the first parallel pipeline 71, and the compressor 1 and the gas-liquid separator 32 are located between the second solenoid valve 62 and the third solenoid valve 63. When the fluorine pump 2 is used for defrosting, the second solenoid valve 62 and the third solenoid valve 63 are both closed, which can prevent the refrigerant from entering the first parallel pipeline 71, thereby reducing the risk of damage to the compressor 1. Optionally, the first parallel pipeline 71 includes a first section, a second section and a third section, one end of the first section is connected to the third connecting pipeline 83, the other end of the first section is connected to the gas-liquid separator 32, one end of the second section is connected to the gas-liquid separator 32, the other end of the second section is connected to the compressor 1, one section of the third section is connected to the compressor 1, and the other end of the third section is connected to the first connecting pipeline 81. The second solenoid valve 62 is arranged on the first section, and the third solenoid valve 63 is arranged on the third section.

[0039] In addition, the low-temperature air source heat pump system further includes a fourth solenoid valve 64 and a fifth solenoid valve 65, both of which are arranged on the second parallel pipeline 72, and the fluorine pump 2 is located between the fourth solenoid valve 64 and the fifth solenoid valve 65. When the compressor 1 is used for cooling, heating or defrosting, the fourth solenoid valve 64 and the fifth solenoid valve 65 are both closed, which can prevent the refrigerant from entering the second parallel pipeline 72. Optionally, the second parallel pipeline 72 includes a fourth section and a fifth section, one end of the fourth section is connected to the third connecting pipeline 83, the second section of the fourth section is connected to the fluorine pump 2, one end of the fifth section is connected to the fluorine pump 2, and the other end of the fifth section is connected to the first connecting pipeline 81. The fourth solenoid valve 64 is arranged on the fourth section, and the fifth solenoid valve 65 is arranged on the fifth section.

[0040] In an embodiment of the present application, the low-temperature air source heat pump system further includes an economizer 33, which includes a first connection port 331, a second connection port 332, a third connection port 333 and a fourth connection port 334. The first connection port 331 is connected to the second connection pipe 82, and the second connection port 332 is connected to the fourth connection pipe 84. The economizer 33 further includes a third connection port 333 and a fourth connection port 334, and the circulation pipeline further includes a first transfer pipe 91 and a second transfer pipe 92. One end of the first transfer pipe 91 is connected to the second connection pipe 82, the other end of the first transfer pipe 91 is connected to the third connection port 333, one end of the second transfer pipe 92 is connected to the fourth connection port 334, and the other end of the second transfer pipe 92 is connected to the compressor 1. When the low-temperature air source heat pump system is in cooling mode or heating mode, part of the refrigerant flowing through the economizer 33 flows to the compressor 1 through the second transfer pipe 92, thereby improving the thermal efficiency of the low-temperature air source heat pump system.

[0041] Optionally, the low-temperature air source heat pump system further includes a first solenoid valve 61, which is disposed on the second transfer pipe 92. When the first solenoid valve 61 is opened, the refrigerant can flow to the compressor 1 through the second transfer pipe 92.

[0042] In the embodiment of the present application, the low-temperature air source heat pump system further includes a plate heat exchanger 34, which includes a first adapter 341, a second adapter 342, a third adapter 343 and a fourth adapter 344; the circulation pipeline further includes a connecting pipe 93, the second connection port 332 and the first adapter 341 are connected through the connecting pipe 93, one end of the fourth connecting pipe 84 is connected to the second adapter 342, and the other end of the fourth connecting pipe 84 is connected to the four-way valve 4. The third adapter 343 and the fourth adapter 344 can be connected to the low-temperature air source heat pump system, so that the water source can exchange heat with the refrigerant flowing through the plate heat exchanger 34, thereby achieving the purpose of hot water production.

[0043] Optionally, the low-temperature air source heat pump system further includes a liquid storage tank 35, which is disposed on the connecting pipe 93. The liquid storage tank 35 can store refrigerant, and the refrigerant in the liquid storage tank 35 can regulate and supplement the refrigerant flowing in the low-temperature air source heat pump system.

[0044] The low-temperature air source heat pump system further includes a first electronic expansion valve 51 and a second electronic expansion valve 52. The first electronic expansion valve 51 is disposed on the second connecting pipe 82, and the first electronic expansion valve 51 can throttle the refrigerant flowing through. The second electronic expansion valve 52 is disposed on the first transfer pipe 91, and the second electronic expansion valve 52 can throttle the refrigerant flowing through the first transfer pipe 91.

[0045] When the low-temperature air source heat pump of the present application is in heating mode, the first solenoid valve 61, the second solenoid valve 62 and the third solenoid valve 63 are opened, and the fourth solenoid valve 64 and the fifth solenoid valve 65 are closed, so that the compressor 1 and the gas-liquid separator 32 are connected to the heating system cycle, and the fluorine pump 2 is closed. Figure 2 As shown, the compressor 1 compresses the gaseous low-temperature and low-pressure refrigerant into a high-temperature and high-pressure gas, which enters the plate heat exchanger 34 through the four-way valve 4. The refrigerant releases heat and condenses into a medium-temperature and high-pressure liquid, and realizes heat exchange with the external water source in the plate heat exchanger 34 to achieve the purpose of hot water production. After the refrigerant flows through the liquid storage tank 35, a part of the refrigerant is evaporated by the economizer 33 and then replenished to the medium-pressure chamber of the compressor 1, and the other part of the refrigerant is throttled into a low-pressure liquid through the first electronic expansion valve 51, and then absorbs heat and evaporates into a low-temperature and low-pressure gas through the fin-tube heat exchanger 31, and finally returns to the compressor 1 through the gas-liquid separator 32 to complete a heating cycle.

[0046] When the low-temperature air source heat pump of the present application is in cooling mode, the first solenoid valve 61, the second solenoid valve 62 and the third solenoid valve 63 are opened, and the fourth solenoid valve 64 and the fifth solenoid valve 65 are closed, so that the compressor 1 and the gas-liquid separator 32 are connected to the heating system cycle, and the fluorine pump 2 is closed. Figure 3 As shown, the compressor 1 compresses the gaseous low-temperature and low-pressure refrigerant into a high-temperature and high-pressure gas, which enters the fin-tube heat exchanger 31 through the four-way valve 4. In the fin-tube heat exchanger 31, the refrigerant releases heat and condenses into a medium-temperature and high-pressure liquid, and then is throttled into a low-pressure liquid through the first electronic expansion valve 51. After that, part of the refrigerant is evaporated through the economizer 33 and returned to the medium-pressure chamber of the compressor 1, and the other part of the refrigerant enters the plate heat exchanger 34 through the economizer 33 and the liquid storage tank 35. The refrigerant absorbs heat and evaporates into a low-temperature and low-pressure gas in the plate heat exchanger 34, and realizes heat exchange with the external water source in the plate heat exchanger 34 to achieve the purpose of cooling water. Finally, the refrigerant returns to the compressor 1 through the gas-liquid separator 32 to complete a refrigeration cycle.

[0047] When the heating mode is running, the fin-tube heat exchanger 31 will be frosted. When the low-temperature air source heat pump detects that the fin-tube heat exchanger 31 has reached the condition that requires defrosting, the ambient temperature is determined:

[0048] ① When the ambient temperature is greater than the predetermined temperature T1, it is determined that the risk of liquid backflow and oil shortage in the low-temperature air source heat pump system is low, and the first defrost mode is executed, and compressor 1 performs rapid defrosting;

[0049] ② When the ambient temperature is less than the predetermined temperature T1, it is determined that the low-temperature air source heat pump system has a high risk of liquid backflow and oil shortage, and the second defrost mode is executed, with fluorine pump 2 performing defrost.

[0050] Optionally, the predetermined temperature T1 may be selected according to the environment in which the low-temperature air source heat pump system is located.

[0051] When the low-temperature air source heat pump of the present application is in the first defrosting mode, the second solenoid valve 62 and the third solenoid valve 63 are opened, and the first solenoid valve 61, the fourth solenoid valve 64 and the fifth solenoid valve 65 are closed, so as to connect the compressor 1 and the gas-liquid separator 32, and close the fluorine pump 2. Figure 4 As shown, the compressor 1 compresses the gaseous low-temperature and low-pressure refrigerant into a high-temperature and high-pressure gas, which enters the fin-tube heat exchanger 31 through the four-way valve 4. In the fin-tube heat exchanger 31, the refrigerant releases heat and condenses into a medium-temperature and high-pressure liquid, and absorbs heat in the process to defrost the surface of the fin-tube heat exchanger 31. It is then throttled into a low-pressure liquid through the first electronic expansion valve 51, and then enters the plate heat exchanger 34 through the economizer 33 and the liquid storage tank 35. The refrigerant absorbs heat in the plate heat exchanger 34 and evaporates into a low-temperature and low-pressure gas. Finally, it returns to the compressor 1 through the gas-liquid separator 32 to complete a defrosting cycle.

[0052] When the low-temperature air source heat pump of the present application is in the first defrosting mode, the fourth solenoid valve 64 and the fifth solenoid valve 65 are opened, the first solenoid valve 61, the second solenoid valve 62 and the third solenoid valve 63 are closed, and the compressor 1 and the gas-liquid separator 32 are closed. During the defrosting process, the fluorine pump 2 works, such as Figure 5 As shown, high-temperature liquid refrigerant flows from the plate heat exchanger 34 into the fluorine pump 2, is transported by the fluorine pump 2, and reaches the fin-tube heat exchanger 31 after passing through the four-way valve 4. The liquid refrigerant exchanges heat with the fin-tube heat exchanger 31, so that the frost layer on the surface of the fin-tube heat exchanger 31 melts. After heat exchange, the liquid refrigerant passes through the first electronic expansion valve 51, the economizer 33 and the liquid storage tank 35 to reach the plate heat exchanger 34, and realizes heat exchange with the external water source in the plate heat exchanger 34, so that the temperature of the liquid refrigerant rises, and then the refrigerant enters the fluorine pump 2 to complete a defrost cycle.

[0053] The low-temperature air source heat pump of the present application uses a combination of compressor 1 and fluorine pump 2 for defrosting. The low-temperature air source heat pump selects the first defrosting mode or the second defrosting mode for defrosting according to the ambient temperature. In this way, when the ambient temperature is low, the fluorine pump 2 performs defrosting and the compressor 1 does not work, which reduces the risk of damage to the compressor 1, increases the service life of the low-temperature air source heat pump system, and improves the reliability of the operation of the low-temperature air source heat pump system.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A low-temperature air source heat pump system, characterized in that: The low-temperature air source heat pump system comprises a compressor, a fluorine pump, a fin-tube heat exchanger, a gas-liquid separator, a circulation pipeline, a first parallel pipeline and a second parallel pipeline, wherein the compressor and the gas-liquid separator are arranged on the first parallel pipeline, the fluorine pump is arranged on the second parallel pipeline, and the fin-tube heat exchanger is arranged on the circulation pipeline; Both ends of the first parallel pipeline are connected to the circulation pipeline respectively, and both ends of the second parallel pipeline are connected to the circulation pipeline respectively. The first parallel pipeline and the second parallel pipeline are connected in parallel.

2. The low-temperature air source heat pump system according to claim 1, characterized in that: The low-temperature air source heat pump system further includes a four-way valve, the circulation pipeline includes a first connecting pipe, a second connecting pipe, a third connecting pipe and a fourth connecting pipe, the first connecting pipe, the second connecting pipe, the third connecting pipe and the fourth connecting pipe are all connected to the four-way valve, the second connecting pipe is connected to one of the first connecting pipe and the third connecting pipe, and the fourth connecting pipe is connected to the other of the first connecting pipe and the third connecting pipe; The first end of the first parallel pipeline and the first end of the second parallel pipeline are both connected to the first connecting pipeline, the second end of the first parallel pipeline and the second end of the second parallel pipeline are both connected to the third connecting pipeline, the second connecting pipeline is connected to the fourth connecting pipeline, and the fin-tube heat exchanger is arranged on the second connecting pipeline.

3. The low-temperature air source heat pump system according to claim 2, characterized in that: The low-temperature air source heat pump system further includes an economizer, which includes a first connection port and a second connection port, wherein the first connection port is connected to the second connection pipe, and the second connection port is connected to the fourth connection pipe.

4. The low-temperature air source heat pump system according to claim 3, characterized in that: The economizer also includes a third connecting port and a fourth connecting port, and the circulation pipeline also includes a first adapter pipe and a second adapter pipe, one end of the first adapter pipe is connected to the second connecting pipe, the other end of the first adapter pipe is connected to the third connecting port, one end of the second adapter pipe is connected to the fourth connecting port, and the other end of the second adapter pipe is connected to the compressor.

5. The low-temperature air source heat pump system according to claim 3, characterized in that: The low-temperature air source heat pump system further includes a plate heat exchanger, and the plate heat exchanger includes a first adapter and a second adapter; The circulation pipeline also includes a connecting pipe, the second connecting port and the first adapter are connected through the connecting pipe, one end of the fourth connecting pipe is connected to the second adapter, and the other end of the fourth connecting pipe is connected to the four-way valve.

6. The low-temperature air source heat pump system according to claim 5, characterized in that: The low-temperature air source heat pump system also includes a liquid storage tank, which is arranged on the connecting pipe.

7. The low-temperature air source heat pump system according to claim 4, characterized in that: The low-temperature air source heat pump system further includes a first electronic expansion valve and a second electronic expansion valve, wherein the first electronic expansion valve is arranged on the second connecting pipe, and the second electronic expansion valve is arranged on the first transfer pipe.

8. The low-temperature air source heat pump system according to claim 4, characterized in that: The low-temperature air source heat pump system further includes a first solenoid valve, which is disposed on the second transfer pipe.

9. The low-temperature air source heat pump system according to claim 1, characterized in that: The low-temperature air source heat pump system also includes a second solenoid valve and a third solenoid valve, wherein the second solenoid valve and the third solenoid valve are both arranged on the first parallel pipeline, and the compressor and the gas-liquid separator are located between the second solenoid valve and the third solenoid valve.

10. The low-temperature air source heat pump system according to claim 1, characterized in that: The low-temperature air source heat pump system further includes a fourth solenoid valve and a fifth solenoid valve, both of which are arranged on the second parallel pipeline, and the fluorine pump is located between the fourth solenoid valve and the fifth solenoid valve.

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