High-energy-efficiency low-temperature cooling and heating heat pump system

Abstract

A high-energy-efficiency low-temperature cold and warm heat pump system comprises an enthalpy increasing compressor, a four-way valve, a gas-liquid separator, a liquid storage tank, a fin type heat exchanger, a water side heat exchanger, an economizer, a heat exchange conversion device and a throttling conversion device, the heat exchange conversion device comprises a main pipeline, a branch pipeline, a distributor and a conversion valve, and one end of the main pipeline and the branch pipeline communicate with a supercooling channel; the change-over valve is communicated with the main pipeline, the other end of the main pipeline is sequentially communicated with the throttling change-over device and the economizer, and the distributor is communicated with the main channel. During refrigeration, a refrigerant enters the throttling conversion device through the main channel, the distributor, the branch pipelines and the supercooling channel of the fin type heat exchanger; in the heating process, a large amount or all of refrigerants flowing out of the throttling conversion device enter the main channel through the conversion valve and the distributor, and a small amount or no refrigerants enter the distributor through the conversion valve, the supercooling channel and the branch pipeline. And during refrigeration, the resistance is reduced, the energy consumption of the enthalpy-increasing compressor is reduced, and the capacity and energy efficiency of the system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to air energy heat pump cooling and heating system. BACKGROUND

[0002] The prior art, Chinese patent CN202410688696.5, a heat pump unit, a heat pump unit operation control method, equipment and storage medium, wherein the heat pump unit includes fin heat exchanger, four-way valve, jacket heat exchanger, gas-liquid separator, compressor, solenoid valve, capillary, first electronic expansion valve, economizer and enthalpy electronic expansion valve; solenoid valve is used for environmental temperature and outlet water temperature to meet the first preset condition when conducting, enthalpy electronic expansion valve is used for environmental temperature and outlet water temperature to meet the second preset condition when conducting, which can solve the problem of low working efficiency of heat pump unit, improve the adaptability of refrigerant circulation under different working conditions of heat pump unit, and improve the overall working efficiency of heat pump unit. The problem is: when working, the energy consumption of compressor is large, and the refrigeration capacity of compressor itself cannot be fully utilized. SUMMARY

[0003] The purpose of the present application is to provide a high energy efficiency low temperature cooling and heating heat pump system, which has the characteristics of improving the refrigeration capacity and energy efficiency without affecting the heating capacity and energy efficiency, and reducing the energy consumption of compressor, so that the system has a larger application environment temperature range.

[0004] The present application is realized as follows: a high energy efficiency low temperature cooling and heating heat pump system, characterized in that: it comprises an enthalpy compressor, a four-way valve, a gas-liquid separator, a liquid storage tank, a fin heat exchanger, a water-side heat exchanger, an economizer, a heat exchange conversion device and a throttling conversion device,

[0005] The heat exchange conversion device comprises a main pipe, a branch pipe, a distributor and a conversion valve, and the branch pipe and the distributor are connected in parallel and then connected in series with the conversion valve to form a series-parallel pipe;

[0006] One end of the main pipe and the branch pipe are respectively communicated with the supercooling channel, the conversion valve is communicated with the main pipe, and the other end of the main pipe is communicated with the throttling conversion device and the economizer in sequence, and the distributor is communicated with the main channel;

[0007] When refrigerating, the refrigerant enters the throttling conversion device through the main channel of the fin heat exchanger, the distributor, the branch pipe and the supercooling channel;

[0008] When heating, the refrigerant flowing out of the throttling conversion device, (i) a large amount or all of the refrigerant enters the main channel through the conversion valve and the distributor, and (ii) a small amount or no refrigerant enters the distributor through the conversion valve, the supercooling channel and the branch pipe.

[0009] The high energy efficiency low temperature cooling and heating heat pump system, characterized in that: the conversion valve is a one-way valve, the outlet end of the one-way valve is communicated with the branch pipe and the distributor, and the inlet end is communicated with the main pipe.

[0010] The high energy efficiency low temperature cold and warm heat pump system, special in, the conversion valve is electromagnetic valve;

[0011] The electromagnetic valve one end and the branch pipe and the distributor are communicated, the other end is communicated with the main pipe.

[0012] The high energy efficiency low temperature cold and warm heat pump system, special in, the conversion valve is two-position three-way valve;

[0013] Two-position three-way valve is connected in series on the main pipe, and is communicated with the branch pipe and the distributor.

[0014] The high energy efficiency low temperature cold and warm heat pump system, special in, the conversion valve is respectively first check valve and second check valve,

[0015] The branch pipe and the distributor are connected in parallel and are connected in series with the first check valve to form a series-parallel pipe; the second check valve one end is communicated with the supercooling channel, the other end is communicated with the main pipe after being connected in parallel with the first check valve;

[0016] When refrigerating, the second check valve is conducted, when heating, the first check valve is conducted.

[0017] The high energy efficiency low temperature cold and warm heat pump system, special in, the conversion valve is respectively first electromagnetic valve and second electromagnetic valve,

[0018] The branch pipe and the distributor are connected in parallel and are connected in series with the first electromagnetic valve to form a series-parallel pipe; the second electromagnetic valve one end is communicated with the supercooling channel, the other end is communicated with the main pipe after being connected in parallel with the first electromagnetic valve;

[0019] When refrigerating, the second electromagnetic valve is conducted, the first electromagnetic valve is not conducted, when heating, the first electromagnetic valve is conducted, the second electromagnetic valve is not conducted.

[0020] The high energy efficiency low temperature cold and warm heat pump system, special in, the conversion valve is respectively third electromagnetic valve and third check valve,

[0021] The branch pipe and the distributor are connected in parallel and are connected in series with the third electromagnetic valve to form a series-parallel pipe; the third check valve one end is communicated with the supercooling channel, the other end is communicated with the main pipe after being connected in parallel with the third electromagnetic valve; When refrigerating, the third check valve is conducted, the third electromagnetic valve is not conducted, when heating, the third electromagnetic valve is conducted.

[0022] Or the branch pipe and the distributor are connected in parallel and are connected in series with the third check valve to form a series-parallel pipe; the third electromagnetic valve one end is communicated with the supercooling channel, the other end is communicated with the main pipe after being connected in parallel with the third check valve; When refrigerating, the third electromagnetic valve is conducted, when heating, the third check valve is conducted, the third electromagnetic valve is not conducted.

[0023] The high energy efficiency low temperature cold and warm heat pump system has the speciality that the throttling conversion device includes main throttling pipeline and vice throttling pipeline and is in parallel,

[0024] The main throttling pipeline includes main throttling valve and main pipeline, and the vice throttling pipeline includes vice throttling valve and throttling check valve; the throttling check valve is cut off in heating, and is conducted in refrigeration.

[0025] The high energy efficiency low temperature cold and warm heat pump system has the speciality that it further includes conversion electromagnetic valve or conversion check valve,

[0026] The conversion electromagnetic valve or conversion check valve and the main channel of the economizer are in parallel, and one end is communicated with the throttling conversion device, and the other end is communicated with the liquid storage tank, one end of the vice channel of the economizer is communicated with the jet port of the enthalpy increasing compressor, and the other end is communicated with the throttling conversion device through the electronic expansion valve,

[0027] The conversion electromagnetic valve or conversion check valve is conducted in refrigeration, and is cut off in heating.

[0028] The high energy efficiency low temperature cold and warm heat pump system has the speciality that it further includes two-position three-way valve,

[0029] The two-position three-way valve is communicated with the liquid storage tank, the throttling conversion device and the main channel of the economizer, one end of the vice channel of the economizer is communicated with the jet port of the enthalpy increasing compressor, and the other end is communicated with the throttling conversion device through the electronic expansion valve,

[0030] The two-position three-way valve is communicated with the liquid storage tank in refrigeration, and is communicated with the liquid storage tank and the main channel of the economizer in heating.

[0031] The high energy efficiency low temperature cold and warm heat pump system has the speciality that it further includes two-position three-way valve, BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is the refrigeration state view of the present application.

[0033] Figure 2 It is the heating state view of the present application.

[0034] Figure 3 It is the refrigeration state view of the second embodiment of the present application.

[0035] Figure 4 It is the heating state view of the second embodiment of the present application.

[0036] Figure 5 It is the refrigeration state view of the third embodiment of the present application.

[0037] Figure 6is a heating state view of the third embodiment of the present application.

[0038] Figure 7 is a heating state view of the third embodiment of the present application.

[0039] Figure 8 is a heating state view of the third embodiment of the present application.

[0040] Figure 9 is a heating state view of the third embodiment of the present application.

[0041] Figure 10 is a heating state view of the third embodiment of the present application.

[0042] Figure 11 is a heating state view of the third embodiment of the present application.

[0043] Figure 12 is a heating state view of the third embodiment of the present application.

[0044] Figure 13 is a heating state view of the third embodiment of the present application.

[0045] Figure 14 is a heating state view of the third embodiment of the present application. DETAILED DESCRIPTION

[0046] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for the purpose of explaining the present application, and should not be understood as limiting the present application.

[0047] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixedly connected, or detachably connected, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium, or can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0048] Example 1

[0049] As shown in Figure 1 , a high-efficiency low-temperature heating and cooling heat pump system includes an enthalpy-increasing compressor 1, a four-way valve 2, a gas-liquid separator 3, a liquid storage tank 4, a fin heat exchanger 5, a water-side heat exchanger 6, an economizer 7, a heat exchange conversion device 8, and a throttling conversion device 9,

[0050] The exhaust port of the enthalpy-increasing compressor 1 is communicated with the D end of the four-way valve 2, the E end of the four-way valve 2 is communicated with the fin heat exchanger 5, the S end of the four-way valve is communicated with the gas-liquid separator 3 and the gas return port of the enthalpy-increasing compressor 1, the C end of the four-way valve is communicated with the water side heat exchanger and the liquid storage tank 4;

[0051] The heat exchange conversion device 8 comprises a main pipeline 81, a branch pipeline 82, a distributor 83 and a conversion valve 84, the branch pipeline 82 and the distributor 83 are connected in parallel and then connected in series with the conversion valve to form a series-parallel pipeline; as shown in the figure, the conversion valve 84 is a one-way valve, the outlet of the one-way valve is communicated with the branch pipeline 82 and the distributor 83, and the inlet is communicated with the main pipeline 81. Figure 1

[0052] One end of the main pipeline 81 and the branch pipeline 82 are respectively communicated with the supercooling channel of the fin heat exchanger 5, the conversion valve 84 is communicated with the main pipeline 81, the other end of the main pipeline 81 is sequentially communicated with the throttling conversion device 9 and the economizer 7, and the distributor 83 is communicated with the main channel of the fin heat exchanger 5;

[0053] During refrigeration, the enthalpy-increasing compressor 1, the D-E end of the four-way valve, the refrigerant passes through the main channel of the fin heat exchanger 5, the distributor 83, the branch pipeline 82, the supercooling channel of the fin heat exchanger 5 and the main pipeline 81 to enter the throttling conversion device 9; the one-way valve is in a cut-off state;

[0054] During heating, the refrigerant flowing out of the throttling conversion device 9, (i) a large amount of refrigerant enters the main channel through the conversion valve 84 and the distributor 83, and (ii) a small amount of refrigerant enters the distributor 83 through the main pipeline 81, the supercooling channel and the branch pipeline 82.

[0055] Advantages: during refrigeration, the fin heat exchanger is a condenser, the refrigerant after heat exchange from the condenser enters the supercooling channel to increase the supercooling degree, thereby effectively improving the refrigerating capacity after throttling and enabling the refrigerating capacity of the compressor itself to be effectively utilized. During heating, the fin heat exchanger is an evaporator in a low-pressure and low-temperature state, the mass flow rate of the refrigerant needs to be increased and the resistance needs to be reduced to improve the heat exchange effect, the present scheme causes a large amount of refrigerant to pass through the conversion valve to the fin heat exchanger for heat exchange, thereby avoiding all refrigerants going to the supercooling channel to increase the resistance and greatly improving the capacity and efficiency of heating.

[0056] The throttling conversion device 9 comprises a main throttling pipeline and a secondary throttling pipeline and is connected in parallel,

[0057] The main throttling pipeline comprises a main throttling valve 91, the secondary throttling pipeline comprises a secondary throttling valve 92 and a throttling one-way valve 93 and is connected in series;

[0058] As shown in the figure, during refrigeration, the refrigerant passes through the main throttling pipeline and the secondary throttling pipeline at the same time; Figure 1

[0059] As shown in the figure, during refrigeration, the refrigerant passes through the main throttling pipeline and the secondary throttling pipeline at the same time; Figure 2 ​​As shown, during heating, the refrigerant enters the switching valve 84 through the main throttling pipeline.

[0060] During heating, the throttling check valve is closed; during cooling, the throttling check valve is open.

[0061] Problems can be solved:

[0062] During heating at low ambient temperature, in order to prevent the fin heat exchanger from returning liquid (ensure the superheat degree) and match the reduced gas delivery of the compressor at high pressure ratio, the system needs to limit the refrigerant flow during low-temperature heating. Therefore, the actual required effective throttling passage should be smaller to maintain appropriate evaporator outlet superheat, protect the compressor, and optimize system energy efficiency; if the main throttle valve is too large, it will cause excessive flow, incomplete evaporation, low superheat, and energy efficiency, and even liquid knock of the compressor, resulting in damage.

[0063] During cooling at high ambient temperature, in order to provide sufficient refrigerant flow to meet the high cooling load demand, prevent the condensing pressure from being too high (protect the compressor), and ensure that the evaporator is fully supplied with liquid (avoid excessive evaporator superheat and capacity reduction), the system needs a larger effective throttling passage during high-temperature cooling. If the main throttle valve is too small, it will cause insufficient liquid supply, evaporator overheating, reduced cooling capacity, soaring condensing pressure, compressor overheating, and dramatic increase in power consumption.

[0064] Indeed, electronic expansion valves can precisely control the valve needle opening degree through stepping motors, thereby continuously adjusting the throttling area; they can solve the problem of needing a larger throttle valve during cooling and a smaller throttle valve during heating. However, with the development of technology, heat pumps that can stably operate during heating at -40℃ low ambient temperature and during cooling at 53℃ high ambient temperature are no longer technical barriers. In such a boundary operating area with a large difference in ambient temperature, a single electronic expansion valve cannot meet the system requirements, so the cooperation of the electronic expansion valve, check valve, and auxiliary throttling pipe in the throttling switching device 9 provided by the present application can effectively solve the above problems and fully realize the capacity and energy efficiency of the system during cooling and heating.

[0065] As a further improvement of the present application: it also includes a switching solenoid valve 10 or a switching check valve 10;

[0066] As shown in Figure 1 The switching check valve 10 and the main channel of the economizer 7 are connected in parallel, one end of which communicates with the throttling switching device 9, and the other end communicates with the liquid storage tank 4. One end of the auxiliary channel of the economizer 7 communicates with the injection port of the enthalpy increasing compressor, and the other end communicates with the throttling switching device 9 through the electronic expansion valve 11.

[0067] As shown in Figure 1As shown, during refrigeration, the refrigerant flowing out of the throttling conversion device 9, the large amount of refrigerant enters the liquid storage tank 4 through the conversion one-way valve 10, and a small amount of refrigerant enters the main channel of the economizer 7 and then enters the liquid storage tank 4, thereby reducing the large amount of energy loss and reducing the energy consumption of the compressor; the refrigeration capacity of the large amount of refrigerant is avoided to be wasted during flowing through the economizer, and the refrigeration capacity and energy efficiency are improved.

[0068] As shown in the figure, Figure 2 As shown, during heating, the water side heat exchanger 6, the liquid storage tank 4, and the main channel of the economizer 7; (1) the refrigerant enters the throttling conversion device 9, (2) a part of the refrigerant enters the injection port of the enthalpy increasing compressor 1 through the electronic expansion valve 11 and the auxiliary channel of the economizer 7. It is ensured that the stable high heating capacity and energy efficiency can be achieved under low ambient temperature.

[0069] The application can also be implemented as shown in the figure, Figure 5 、 Figure 6 As shown, the application further comprises a two-position three-way reversing valve 12,

[0070] The two-position three-way reversing valve 12 is in communication with the liquid storage tank 4, the throttling conversion device 9, and the main channel of the economizer 7, one end of the auxiliary channel of the economizer 7 is in communication with the injection port of the enthalpy increasing compressor, and the other end is in communication with the throttling conversion device 9 through the electronic expansion valve;

[0071] As shown in the figure, Figure 5 As shown, during refrigeration, the throttling conversion device 9, the A1-A2 end of the two-position three-way reversing valve 12, and the liquid storage tank 4 are in communication,

[0072] As shown in the figure, Figure 6 As shown, during heating, the liquid storage tank 4, the A2-A3 end of the two-position three-way reversing valve 12, the main channel of the economizer 7, and the throttling conversion device 9 are sequentially in communication, and the refrigerant is in communication with the electronic expansion valve 11, the auxiliary channel of the economizer 7, and the injection port of the enthalpy increasing compressor.

[0073] Embodiment 2

[0074] As shown in the figure, Figure 3 、 Figure 4 As shown, the conversion valve 84 is an electromagnetic valve;

[0075] One end of the electromagnetic valve is in communication with the branch pipeline 82 and the distributor 83, and the other end is in communication with the main pipeline 81.

[0076] The enthalpy increasing compressor 1, the D-E end of the four-way valve, the main channel of the fin heat exchanger 5, the distributor 83, the branch pipeline 82, the supercooling channel of the fin heat exchanger 5, the main pipeline 81, and the throttling conversion device 9 are in communication; the one-way valve is in a cut-off state;

[0077] When heating, the refrigerant flowing out of the throttling switching device 9, (1) a large amount of refrigerant, enters the main passage through the switching valve 84 and the distributor 83, (2) a small amount of refrigerant, the main passage 81, the subcooling passage, the branch passage 82, enters the distributor 83.

[0078] Embodiment 3

[0079] As shown in Figure 5 , Figure 6 , the switching valve 84 is a two-position three-way valve.

[0080] The A1 and A3 of the two-position three-way valve are connected in series on the main passage 81, and the A2 is connected in communication with the branch passage 82 and the distributor 83.

[0081] As shown in Figure 5 , when refrigerating, the refrigerant flowing out of the throttling switching device 9, the refrigerant, the enthalpy increasing compressor 1, the D-E end of the four-way valve, the main passage of the fin heat exchanger 5, the distributor 83, the branch passage 82, the subcooling passage of the fin heat exchanger 5, the main passage 81, the A3-A1 of the two-position three-way valve, enters the throttling switching device 9.

[0082] As shown in Figure 6 , when heating, the refrigerant flowing out of the throttling switching device 9, the refrigerant, enters the main passage through the A1-A2 end of the two-position three-way valve and the distributor 83.

[0083] Embodiment 4

[0084] As shown in Figure 7 , Figure 8 , the switching valve 84 is respectively a first check valve 841 and a second check valve 842,

[0085] The branch passage 82 and the distributor 83 are connected in parallel and then connected in series with the first check valve 841 to form a series-parallel passage; one end of the second check valve 842 is connected in communication with the subcooling passage, and the other end is connected in parallel with the first check valve 841 and then connected in communication with the main passage 81;

[0086] As shown in Figure 7 , when refrigerating, the refrigerant flowing out of the throttling switching device 9, the refrigerant, the enthalpy increasing compressor 1, the D-E end of the four-way valve, the main passage of the fin heat exchanger 5, the distributor 83, the branch passage 82, the subcooling passage of the fin heat exchanger 5, the second check valve 842, the main passage 81, enters the throttling switching device 9.

[0087] As shown in Figure 8 , when heating, the refrigerant flowing out of the throttling switching device 9, the refrigerant, enters the main passage of the fin heat exchanger through the first check valve 841 and the distributor 83.

[0088] Embodiment 5

[0089] As shown in Figure 9 , Figure 10As shown, the switching valve 84 is the first solenoid valve 843 and the second solenoid valve 844 respectively.

[0090] Branch pipe 82 and distributor 83 are connected in parallel and then connected in series with the first solenoid valve 843 to form a series-parallel pipeline; one end of the second solenoid valve 844 is connected to the subcooling channel of the finned heat exchanger, and the other end is connected to the main pipe 81 after being connected in parallel with the first solenoid valve 843.

[0091] like Figure 9 As shown, during refrigeration, the refrigerant enters the throttling conversion device 9 through the enthalpy-increasing compressor 1, the D-E ends of the four-way valve, the main channel of the finned heat exchanger 5, the distributor 83, the branch pipe 82, the subcooling channel of the finned heat exchanger 5, the second solenoid valve 844, and the main pipe 81.

[0092] like Figure 10 As shown, during heating, the refrigerant flowing out of the throttling conversion device 9 enters the main channel of the finned heat exchanger via the first solenoid valve 843 and the distributor 83.

[0093] Example 6

[0094] like Figure 11 , Figure 12 As shown, the switching valves are respectively the third solenoid valve 845 and the third check valve 846.

[0095] like Figure 11 As shown, branch pipe 82 and distributor 83 are connected in parallel and then connected in series with the third solenoid valve to form a series-parallel pipeline; one end of the third check valve 846 is connected to the subcooling channel of the finned heat exchanger, and the other end is connected in parallel with the third solenoid valve 845 and then connected to the main pipe 81.

[0096] like Figure 11 As shown, during refrigeration, the refrigerant enters the throttling conversion device 9 through the enthalpy-increasing compressor 1, the D-E ends of the four-way valve, the main channel of the finned heat exchanger 5, the distributor 83, the branch pipe 82, the subcooling channel of the finned heat exchanger 5, the third one-way valve 846, and the main pipe 81.

[0097] like Figure 12 As shown, during heating, the refrigerant flowing out of the throttling conversion device 9 enters the main channel of the finned heat exchanger via the third solenoid valve 846 and the distributor 83.

[0098] Or such as Figure 13 , Figure 14 As shown, branch pipe 82 and distributor 83 are connected in parallel and then connected in series with third check valve 846 to form a series-parallel pipeline; one end of third solenoid valve 845 is connected to subcooling channel, and the other end is connected in parallel with third check valve 846 and then connected to main pipe 81.

[0099] like Figure 13As shown, during refrigeration, the refrigerant enters the throttling conversion device 9 through the enthalpy-increasing compressor 1, the D-E ends of the four-way valve, the main channel of the finned heat exchanger 5, the distributor 83, the branch pipe 82, the subcooling channel of the finned heat exchanger 5, the third solenoid valve 845, and the main pipe 81.

[0100] like Figure 14 As shown, during heating, the refrigerant flowing out of the throttling conversion device 9 enters the main channel of the finned heat exchanger via the third one-way valve 846 and the distributor 83.

[0101] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A high-efficiency low-temperature heating and cooling heat pump system, characterized in that: This includes an enthalpy-increasing compressor, a four-way valve, a gas-liquid separator, a liquid receiver, a finned heat exchanger, a water-side heat exchanger, an economizer, a heat exchange conversion device, and a throttling conversion device. The heat exchange conversion device includes a main pipeline, branch pipelines, distributors, and conversion valves. The branch pipelines and distributors are connected in parallel and then connected in series with the conversion valves to form a series-parallel pipeline. One end of the main pipeline and the branch pipeline are connected to the subcooling aisle respectively. The switching valve is connected to the main pipeline. The other end of the main pipeline is connected to the throttling switching device and the economizer in sequence. The distributor is connected to the main channel. During refrigeration, the refrigerant enters the throttling conversion device through the main channel, distributor, branch pipes, and subcooling channel of the finned heat exchanger; During heating, the refrigerant flowing out of the throttling switching device (i) a large amount or all of the refrigerant enters the main channel through the switching valve and distributor, and (ii) a small amount or no refrigerant enters the distributor through the switching valve, subcooling channel and branch pipe.

2. The high-efficiency low-temperature heating and cooling heat pump system according to claim 1, characterized in that: The switching valve is a one-way valve, with its outlet end connected to the branch pipeline and distributor, and its inlet end connected to the main pipeline.

3. The high-efficiency low-temperature heating and cooling heat pump system according to claim 1, characterized in that: The switching valve is a solenoid valve; One end of the solenoid valve is connected to the branch pipeline and distributor, and the other end is connected to the main pipeline.

4. The high-efficiency low-temperature heating and cooling heat pump system according to claim 1, characterized in that: The switching valve is a two-position three-way valve; A two-position three-way valve is connected in series on the main pipeline and is also connected to the branch pipeline and distributor.

5. The high-efficiency low-temperature heating and cooling heat pump system according to claim 1, characterized in that: The switching valves are respectively a first check valve and a second check valve. The branch pipe and the distributor are connected in parallel and then connected in series with the first check valve to form a series-parallel pipeline; one end of the second check valve is connected to the subcooling passage, and the other end is connected to the main pipeline after being connected in parallel with the first check valve. When cooling, the second check valve is open; when heating, the first check valve is open.

6. The high-efficiency low-temperature heating and cooling heat pump system according to claim 1, characterized in that: The switching valves are respectively the first solenoid valve and the second solenoid valve. The branch pipe and the distributor are connected in parallel and then connected in series with the first solenoid valve to form a series-parallel pipeline; one end of the second solenoid valve is connected to the subcooling channel, and the other end is connected to the main pipeline after being connected in parallel with the first solenoid valve. When cooling, the second solenoid valve is open and the first solenoid valve is closed; when heating, the first solenoid valve is open and the second solenoid valve is closed.

7. The high-efficiency low-temperature heating and cooling heat pump system according to claim 1, characterized in that: The switching valves are respectively the third solenoid valve and the third check valve. The branch pipe and distributor are connected in parallel and then connected in series with the third solenoid valve to form a series-parallel pipeline; one end of the third check valve is connected to the subcooling channel, and the other end is connected in parallel with the third solenoid valve and then connected to the main pipeline; when cooling, the third check valve is open and the third solenoid valve is not open; when heating, the third solenoid valve is open. Alternatively, the branch pipe and distributor can be connected in parallel and then connected in series with the third check valve to form a series-parallel pipeline; one end of the third solenoid valve is connected to the subcooling channel, and the other end is connected in parallel with the third check valve and then connected to the main pipeline; the third solenoid valve is open when cooling, and the third check valve is open when heating, while the third solenoid valve is not open.

8. The high-efficiency low-temperature heating and cooling heat pump system according to claim 1, characterized in that: The throttling conversion device includes a main throttling pipeline and a secondary throttling pipeline connected in parallel. The main throttling pipeline includes a main throttling valve, and the secondary throttling pipeline includes a secondary throttling valve and a throttling check valve; during heating, the throttling check valve is closed; during cooling, the throttling check valve is open.

9. A high-efficiency low-temperature heating and cooling heat pump system according to claim 1, 2, 3, 4, 5, 6, 7 or 8, characterized in that: It also includes switching solenoid valves or switching check valves; The main channel of the economizer is connected in parallel with the switching solenoid valve or switching check valve, with one end connected to the throttling switching device and the other end connected to the liquid storage tank. One end of the economizer's secondary channel is connected to the jet port of the enthalpy-increasing compressor, and the other end is connected to the throttling switching device through the electronic expansion valve. When cooling, the solenoid valve or check valve is activated; when heating, it is deactivated.

10. A high-efficiency low-temperature heating and cooling heat pump system according to claim 1, 2, 3, 4, 5, 6, 7 or 8, characterized in that: It also includes a two-position three-way directional valve. The two-position three-way reversing valve is connected to the main channel of the liquid storage tank, the throttling conversion device and the economizer. One end of the auxiliary channel of the economizer is connected to the jet port of the enthalpy-increasing compressor, and the other end is connected to the throttling conversion device through the electronic expansion valve. During cooling, the two-position three-way reversing valve is connected to the liquid receiver tank; during heating, the two-position three-way valve is connected to the main channel of the liquid receiver tank and the economizer.

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