Automatic refrigerant quantity adjusting system of double-cold-source unit

Abstract

The utility model relates to the technical field of heat management, in particular to a double-cold-source unit refrigerant quantity automatic adjusting system which comprises a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, a multi-way valve, a first expansion valve, a refrigerant backflow pipeline, a first control valve, a heating balance pipeline and a second control valve. A sixth port of the first heat exchanger is communicated with an inlet of the second heat exchanger through the first expansion valve; an outlet of the second heat exchanger is communicated with a third port; and a fourth port is communicated with an air suction end of the compressor. The first control valve is arranged on a refrigerant backflow pipeline, one end of the refrigerant backflow pipeline communicates with a bypass pipeline of the third heat exchanger, and the other end communicates with the air suction end of the compressor. The second control valve is arranged on a heating balance pipeline, one end of the heating balance pipeline communicates with the outlet end of the third heat exchanger, and the other end of the heating balance pipeline communicates with an inlet of the first expansion valve so that refrigerants can flow to the third heat exchanger through the heating balance pipeline.

Description

Technical Field

[0001] The utility model relates to the technical field of thermal management, in particular to a refrigerant quantity automatic adjustment system for a dual-cold source unit. Background Art

[0002] The existing dual-cold source unit refrigerant quantity automatic adjustment system will open the second control valve during heating to balance the refrigerant. However, the general heating mode is used in winter, when the ambient temperature is low, and the dual-cold source switching valve at the inlet of the evaporative condenser is closed, and only the second control valve is opened to allow excess refrigerant to flow to the pipeline that does not participate in the circulation in the heating mode. The pressure at the outlet of the balancing valve is the pressure before the electronic first expansion valve in the system. The pressure here is higher, higher than the pressure at the evaporative condenser end. At this time, the refrigerant stored in the evaporative condenser cannot be bypassed, and will only flow from the high-pressure side to the low-pressure side, that is, from the second control valve into the evaporative condenser, so that the amount of refrigerant in the circulation system is reduced. Once the second control valve is not controlled in time, it is easy to cause too much refrigerant in the evaporative condensing section, and too little refrigerant in the circulation system, and without switching the mode, the refrigerant in the evaporative condenser cannot be returned to the heating circulation system.

[0003] Therefore, there is an urgent need for an automatic refrigerant quantity adjustment system for a dual-cold source unit to solve the above problems. Utility Model Content

[0004] The utility model aims to provide a dual-cold source unit refrigerant quantity automatic adjustment system, which can solve the problem of insufficient refrigerant in the heating mode circulation system without switching modes.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] Provided is a refrigerant quantity automatic regulation system for a dual cold source unit, comprising a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, a multi-way valve, a first expansion valve, a refrigerant return pipeline, a first control valve, a heating balance pipeline and a second control valve, wherein the multi-way valve comprises a first port, a second port, a third port and a fourth port that can be connected in any two, the exhaust end of the compressor is connected to the first port, the second port is connected to the fifth port on the first side of the first heat exchanger, the sixth port on the first side of the first heat exchanger is connected to the inlet of the second heat exchanger via the first expansion valve, and the second The outlet of the heat exchanger is connected to the third port, the fourth port is connected to the suction end of the compressor, the first control valve is arranged on the refrigerant return pipeline, one end of the refrigerant return pipeline is connected to the bypass pipeline of the third heat exchanger, and the other end is connected to the suction end of the compressor, the second control valve is arranged on the heating balance pipeline, one end of the heating balance pipeline is connected to the outlet end of the third heat exchanger, and the other end is connected to the inlet of the first expansion valve, so that when the cooling mode is switched to the heating mode, the refrigerant can flow to the third heat exchanger through the heating balance pipeline;

[0007] In the heating mode of the automatic refrigerant quantity adjustment system for the dual cold source units, the first heat exchanger is a condenser and the second heat exchanger is an evaporator. In the cooling mode of the automatic refrigerant quantity adjustment system for the dual cold source units, the third heat exchanger is a condenser and the first heat exchanger is an evaporator.

[0008] As a preferred solution of the automatic refrigerant quantity adjustment system of the dual cold source unit, it also includes a dual cold source switching valve, and the exhaust end is connected to the inlet of the third heat exchanger through the dual cold source switching valve.

[0009] As a preferred solution of the automatic refrigerant quantity adjustment system of a dual cold source unit, it also includes a refrigeration check valve, and the outlet of the third heat exchanger is connected to the seventh port on the first side of the first heat exchanger through the refrigeration check valve and the first expansion valve. The refrigeration check valve can allow the refrigerant to flow from the third heat exchanger to the first expansion valve, and the refrigeration check valve is arranged in parallel with the second control valve.

[0010] As a preferred solution of the automatic refrigerant quantity adjustment system of the dual cold source unit, it also includes an economizer, a port on the first side of the economizer is selectively connected to the outlet of the third heat exchanger and the sixth port, and another port on the first side of the economizer is connected to the inlet of the first expansion valve.

[0011] As a preferred solution of the automatic refrigerant quantity adjustment system of the dual cold source unit, the inlet of the second side of the economizer is selectively connected to the outlet of the third heat exchanger and the sixth port, and the outlet of the second side of the economizer is connected to the air supply port of the compressor.

[0012] As a preferred solution of the automatic refrigerant quantity adjustment system for dual cold source units, it also includes a second expansion valve, which is arranged on the upstream pipeline of the inlet of the second side of the economizer.

[0013] As a preferred solution of the automatic refrigerant quantity adjustment system of the dual cold source unit, it also includes a first air-supply check valve, which is arranged on the upstream pipeline of the inlet of the second side of the economizer to limit the refrigerant to flow to the inlet of the second side of the economizer in one direction;

[0014] And / or, it also includes a second air-supply one-way valve, which is arranged on the pipeline between the outlet of the second side of the economizer and the air-supply port to limit the refrigerant to flow to the air-supply port in one direction.

[0015] As a preferred solution of the automatic refrigerant quantity adjustment system of the dual cold source unit, it also includes a drying filter barrel, the inlet of the drying filter barrel is selectively connected to the outlet of the third heat exchanger and the sixth port, and the downstream pipeline of the outlet of the drying filter barrel is provided with the economizer.

[0016] As a preferred solution of the automatic refrigerant quantity adjustment system of the dual cold source unit, it also includes a return oil three-way valve, the two inlets of the return oil three-way valve are respectively connected to the oil storage area of ​​the first heat exchanger and the exhaust end, and the outlet of the return oil three-way valve is connected to the suction end.

[0017] As a preferred solution of the automatic refrigerant quantity adjustment system of the dual cold source unit, it also includes an oil separator, the inlet of the oil separator is connected to the exhaust end, the refrigerant outlet of the oil separator is connected to the first port and the inlet of the dual cold source switching valve, and the oil outlet of the oil separator is connected to the suction end.

[0018] Beneficial effects of the utility model:

[0019] The utility model provides a refrigerant quantity automatic adjustment system for a dual cold source unit, comprising a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, a multi-way valve, a first expansion valve, a refrigerant return pipeline, a first control valve, a heating balance pipeline and a second control valve. The multi-way valve comprises a first port, a second port, a third port and a fourth port which can be connected in any two. The exhaust end of the compressor is connected to the first port, the second port is connected to the fifth port on the first side of the first heat exchanger, the sixth port on the first side of the first heat exchanger is connected to the inlet of the second heat exchanger through the first expansion valve, the outlet of the second heat exchanger is connected to the third port, and the fourth port is connected to the suction end of the compressor. The first control valve is arranged on the refrigerant return pipeline, one end of the refrigerant return pipeline is connected to the bypass pipeline of the third heat exchanger, and the other end is connected to the suction end of the compressor. The second control valve is arranged on the heating balance pipeline, one end of the heating balance pipeline is connected to the outlet end of the third heat exchanger, and the other end is connected to the inlet end of the first expansion valve, so that when the cooling mode is switched to the heating mode, the refrigerant can flow to the third heat exchanger through the heating balance pipeline. In the heating mode, the first heat exchanger is a condenser, the second heat exchanger is an evaporator, and the double cold source unit refrigerant quantity automatic adjustment system is in the cooling mode, the third heat exchanger is a condenser, and the first heat exchanger is an evaporator. When the double cold source unit refrigerant quantity automatic adjustment system is changed from the cooling mode to the heating mode, the second control valve can be opened to allow the refrigerant to flow from the heating balance pipeline to the third heat exchanger to flow out of the heating circuit. Once the refrigerant flows out too much, the first control valve can also be opened to allow the refrigerant to flow out from the bypass pipeline of the third heat exchanger, and flow to the suction end of the compressor through the refrigerant return pipeline to return to the heating circuit. The automatic refrigerant quantity adjustment system of the dual-cold source unit can solve the problem of excessive refrigerant outflow in the heating mode circulation system without switching modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a refrigerant quantity automatic adjustment system (refrigerant adjustment) of a dual cold source unit provided by an embodiment of the utility model;

[0021] Figure 2 It is a structural schematic diagram of a refrigerant quantity automatic adjustment system (heating mode) of a dual cold source unit provided by an embodiment of the utility model;

[0022] Figure 3 It is a structural schematic diagram of the automatic refrigerant quantity adjustment system (refrigeration mode) of the dual cold source unit provided by the embodiment of the utility model.

[0023] In the figure:

[0024] 1. compressor; 2. first heat exchanger; 21. fifth port; 22. sixth port; 23. seventh port;

[0025] 3. Second heat exchanger; 4. Third heat exchanger; 5. Multi-way valve; 51. First port; 52. Second port; 53. Third port; 54. Fourth port;

[0026] 6. First expansion valve; 7. Refrigerant return pipeline; 8. First control valve; 9. Heating balance pipeline; 10. Second control valve; 11. Dual cold source switching valve; 12. Refrigeration one-way valve; 13. Economizer; 14. Second expansion valve; 15. First air supply one-way valve; 16. Second air supply one-way valve; 17. Dry filter barrel; 18. Oil return three-way valve; 19. Oil separator. DETAILED DESCRIPTION

[0027] The technical solution of the utility model is further described below in conjunction with the accompanying drawings and implementation methods. It is understood that the specific embodiments described herein are only used to explain the utility model, rather than to limit the utility model. It should also be noted that, for the convenience of description, only the parts related to the utility model are shown in the accompanying drawings, rather than all.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0030] like Figure 1-Figure 3 As shown, the automatic refrigerant quantity adjustment system of the dual cold source unit of this embodiment includes a compressor 1, a first heat exchanger 2, a second heat exchanger 3, a third heat exchanger 4, a multi-way valve 5, a first expansion valve 6, a refrigerant return pipeline 7, a first control valve 8, a heating balance pipeline 9 and a second control valve 10.

[0031] The multi-way valve 5 includes a first port 51, a second port 52, a third port 53 and a fourth port 54, which can be connected in any two. The exhaust end of the compressor 1 is connected to the first port 51, the second port 52 is connected to the fifth port 21 on the first side of the first heat exchanger 2, the sixth port 22 on the first side of the first heat exchanger 2 is connected to the inlet of the second heat exchanger 3 through the first expansion valve 6, the outlet of the second heat exchanger 3 is connected to the third port 53, and the fourth port 54 is connected to the suction end of the compressor 1.

[0032] The first control valve 8 is arranged on the refrigerant return pipeline 7, one end of which is connected to the bypass pipeline of the third heat exchanger 4, and the other end is connected to the suction end of the compressor 1. The second control valve 10 is arranged on the heating balance pipeline 9, one end of which is connected to the outlet end of the third heat exchanger 4, and the other end is connected to the inlet end of the first expansion valve 6, so that when the cooling mode is switched to the heating mode, the refrigerant can flow to the third heat exchanger 4 through the heating balance pipeline 9.

[0033] In the heating mode of the automatic refrigerant quantity adjustment system of the dual cold source unit, the first heat exchanger 2 is a condenser, and the second heat exchanger 3 is an evaporator. In the cooling mode of the automatic refrigerant quantity adjustment system of the dual cold source unit, the third heat exchanger 4 is a condenser, and the first heat exchanger 2 is an evaporator. Optionally, the first heat exchanger 2 is a shell and tube heat exchanger, the second heat exchanger 3 is a fin heat exchanger, and the third heat exchanger 4 is an evaporative condenser. Optionally, in this embodiment, the first side of the first heat exchanger 2 is a shell side, and the second side is a tube side, the refrigerant flows through the first side, and the coolant flows through the second side.

[0034] When the refrigerant quantity automatic regulating system of the dual cold source unit changes from the cooling mode to the heating mode, the second control valve 10 can be opened to allow the refrigerant to flow from the heating balance pipeline 9 to the third heat exchanger 4 to flow out of the heating circuit, so as to solve the problem of the difference in the refrigerant dosage required for the cooling mode and the heating mode. Once the refrigerant flows out too much, the first control valve 8 can also be opened to allow the refrigerant to flow out from the bypass pipeline of the third heat exchanger 4, and flow to the suction end of the compressor 1 through the refrigerant return pipeline 7 to return to the heating circuit. Therefore, the refrigerant quantity automatic regulating system of the dual cold source unit can solve the problem of excessive refrigerant outflow in the heating mode circulation system without switching modes.

[0035] Preferably, the dual cold source unit refrigerant quantity automatic adjustment system further includes a dual cold source switching valve 11, and the exhaust end is connected to the inlet of the third heat exchanger 4 through the dual cold source switching valve 11. The dual cold source switching valve 11 is opened in the cooling mode and closed in the heating mode.

[0036] Preferably, the dual cold source unit refrigerant quantity automatic regulation system further includes a refrigeration check valve 12, and the outlet of the third heat exchanger 4 is connected to the seventh port 23 of the first side of the first heat exchanger 2 through the refrigeration check valve 12 and the first expansion valve 6. The refrigeration check valve 12 can allow the refrigerant to flow from the third heat exchanger 4 to the first expansion valve 6 to limit the flow direction of the refrigerant in the refrigeration mode. The refrigeration check valve 12 is arranged in parallel with the second control valve 10, and the flow directions of the pipelines where the two are located are opposite, and the refrigeration check valve 12 is only opened in the refrigeration state, and the second control valve 10 is only opened when the refrigeration mode is switched to the heating mode.

[0037] Preferably, the dual cold source unit refrigerant quantity automatic regulation system also includes an economizer 13, a port on the first side of the economizer 13 is selectively connected to the outlet of the third heat exchanger 4 and the sixth port 22, and another port on the first side of the economizer 13 is connected to the inlet of the first expansion valve 6.

[0038] Preferably, the inlet of the second side of the economizer 13 is selectively connected to the outlet of the third heat exchanger 4 and the sixth port 22, and the outlet of the second side of the economizer 13 is connected to the air supply port of the compressor 1 to achieve air supply. Preferably, the dual cold source unit refrigerant quantity automatic adjustment system also includes a second expansion valve 14, which is arranged on the upstream pipeline of the inlet of the second side of the economizer 13.

[0039] In order to limit the flow direction of the refrigerant, preferably, the dual-cold-source unit refrigerant quantity automatic regulating system further includes a first gas-injection check valve 15, which is arranged on the upstream pipeline of the inlet on the second side of the economizer 13 to limit the refrigerant to flow only in one direction to the inlet on the second side of the economizer 13. Preferably, the dual-cold-source unit refrigerant quantity automatic regulating system further includes a second gas-injection check valve 16, which is arranged on the pipeline between the outlet on the second side of the economizer 13 and the gas-injection port to limit the refrigerant to flow only in one direction to the gas-injection port.

[0040] Preferably, the dual cold source unit refrigerant quantity automatic regulation system further comprises a drying filter barrel 17, the inlet of the drying filter barrel 17 is selectively connected to the outlet of the third heat exchanger 4 and the sixth port 22, and the downstream pipeline of the outlet of the drying filter barrel 17 is provided with an economizer 13.

[0041] After the dual-cold source unit refrigerant quantity automatic regulation system has been running for a period of time, a small amount of the lubricating oil of the compressor 1 will flow into the system circuit and accumulate in the oil storage area of ​​the first heat exchanger 2. In order to recover this part of the lubricating oil, preferably, the dual-cold source unit refrigerant quantity automatic regulation system also includes a return oil three-way valve 18, and the two inlets of the return oil three-way valve 18 are respectively connected to the oil storage area and the exhaust end of the first heat exchanger 2, and the outlet of the return oil three-way valve 18 is connected to the suction end, that is, the high-pressure refrigerant at the exhaust end is used to drive the lubricating oil flowing back from the oil storage area of ​​the first heat exchanger 2 to enter the air inlet end of the compressor 1, that is, return to the compressor 1.

[0042] Optionally, the inner diameter of the return oil three-way valve 18 is changed to increase the flow rate of the refrigerant so as to drive the lubricating oil to flow downstream. A regulating valve and a solenoid valve are provided upstream of the first inlet of the return oil three-way valve 18 to regulate the flow of the refrigerant entering the return oil three-way valve 18. A regulating valve is also provided upstream of the second inlet of the return oil three-way valve 18 to control the flow of the lubricating oil flowing back. A regulating valve is also provided downstream of the outlet of the return oil three-way valve 18 to control the flow of the refrigerant and lubricating oil flowing to the compressor 1.

[0043] In order to further reduce the lubricating oil entering the system circuit, preferably, the dual cold source unit refrigerant quantity automatic adjustment system further includes an oil separator 19, the inlet of the oil separator 19 is connected to the exhaust end, the refrigerant outlet of the oil separator 19 is connected to the first port 51 and the inlet of the dual cold source switching valve 11, and the oil outlet of the oil separator 19 is connected to the suction end. The oil separator 19 can separate the refrigerant and lubricating oil flowing out of the exhaust end of the compressor 1, and send the lubricating oil back to the suction end, and send the refrigerant into the system circuit.

[0044] Optionally, an oil return capillary and a regulating valve are provided downstream of the oil outlet of the oil separator 19. Optionally, a safety valve is also provided at the oil separator 19 to regulate the pressure in the system circuit, and a charging valve is also provided to charge the refrigerant.

[0045] In order to limit the flow direction of the refrigerant in the dual cold source unit refrigerant quantity automatic adjustment system in the heating mode, a one-way valve is provided on the downstream pipeline of the sixth port 22 of the first heat exchanger 2, and a one-way valve is provided on the pipeline between the first expansion valve 6 and the second heat exchanger 3.

[0046] like Figure 2As shown, in the heating mode, the refrigerant flows out from the exhaust end of the compressor 1, enters the shell side of the first heat exchanger 2 through the oil separator 19 and the four-way valve, and then passes through the drying filter barrel 17 and is divided into two paths, one path enters the first side of the economizer 13, and the other path enters the second side of the economizer 13 through the second expansion valve 14. The refrigerant flowing out of the first side outlet of the economizer 13 enters the second heat exchanger 3 after passing through the first expansion valve 6, and returns to the suction end of the compressor 1 through the four-way valve after heat exchange, completing a heating cycle.

[0047] In order to limit the flow direction of the refrigerant in the dual cold source unit refrigerant quantity automatic adjustment system in the cooling mode, a one-way valve is provided on the pipeline between the first expansion valve 6 and the seventh port 23 of the first heat exchanger 2 .

[0048] like Figure 3 As shown, in the refrigeration mode, the refrigerant flows out from the exhaust end of the compressor 1, enters the third heat exchanger 4 through the oil separator 19 and the dual cold source switching valve 11, and after heat exchange, flows through the refrigeration check valve 12, the drying filter barrel 17, the economizer 13, and the first expansion valve 6, and then enters the seventh port 23 of the first heat exchanger 2, and then flows back to the suction end of the compressor 1 from the fifth port 21 through the multi-way valve 5, completing a refrigeration cycle.

[0049] In order to monitor the temperature, pressure and other parameters of the automatic refrigerant quantity regulation system of the dual cold source unit in order to accurately control each valve, optionally, the suction end of the compressor 1 is provided with a pressure sensor, and the upstream pipeline of the suction end is provided with an NTC temperature sensor to measure the suction pressure and suction temperature. Optionally, the inlet and outlet of the tube side of the first heat exchanger 2 are provided with an NTC temperature sensor to measure the temperature of the inlet and outlet coolant. Optionally, a safety valve and a charging valve are also provided at the first heat exchanger 2. A pressure sensor and an NTC temperature sensor are provided on the downstream pipeline of the outlet on the second side of the economizer 13 to measure the replenishing air pressure and replenishing air temperature.

[0050] When switched to heating mode, when the system condensing temperature ≥ system design condensing temperature + setting deviation, the system design condensing temperature defaults to the condensing temperature when the heating water temperature is set to 45°C. If the user sets other outlet water temperatures, the condensing temperature deviation = set outlet water temperature - 45°C. At this time, there is too much refrigerant, the system opens the second control valve 10, and the refrigerant bypasses to the third heat exchanger 4 for storage. When the system condensing temperature ≤ system design condensing temperature + setting deviation, the second control valve 10 is closed, and the refrigerant bypass is stopped to ensure that the amount of refrigerant in the circulation system is appropriate and will not be too much to cause a high pressure alarm.

[0051] In heating mode, when the system evaporation temperature is less than or equal to the design evaporation temperature corresponding to the ambient temperature, the first control valve 8 is opened, and the refrigerant in the evaporation condenser is pumped back into the circulation system using the low pressure at the suction end of the compressor 1, thereby increasing the amount of refrigerant in the system. When the system evaporation temperature is greater than or equal to the design evaporation temperature corresponding to the ambient temperature, the first control valve 8 is closed, and the refrigerant replenishment in the system is stopped, ensuring that the amount of refrigerant in the circulation system is appropriate and will not be too little to cause a low pressure alarm.

[0052] The automatic refrigerant quantity adjustment system of the dual-cold source unit can solve the problem of refrigerant quantity mismatch during the transition from cooling mode to heating mode, making the system operation more stable and controlling the system refrigerant quantity within a reasonable range, which can ensure better system performance and higher energy efficiency.

[0053] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. The automatic refrigerant quantity adjustment system of the dual cold source unit is characterized by: The invention comprises a compressor (1), a first heat exchanger (2), a second heat exchanger (3), a third heat exchanger (4), a multi-way valve (5), a first expansion valve (6), a refrigerant return pipeline (7), a first control valve (8), a heating balance pipeline (9) and a second control valve (10), wherein the multi-way valve (5) comprises a first port (51), a second port (52), a third port (53) and a fourth port (54) which can be connected in any two, the exhaust end of the compressor (1) is connected to the first port (51), the second port (52) is connected to the fifth port (21) on the first side of the first heat exchanger (2), and the sixth port (22) on the first side of the first heat exchanger (2) is connected to the inlet port (21) of the second heat exchanger (3) via the first expansion valve (6). The outlet of the second heat exchanger (3) is connected to the third port (53), the fourth port (54) is connected to the suction end of the compressor (1), the first control valve (8) is arranged on the refrigerant return pipeline (7), one end of the refrigerant return pipeline (7) is connected to the bypass pipeline of the third heat exchanger (4), and the other end is connected to the suction end of the compressor (1), the second control valve (10) is arranged on the heating balance pipeline (9), one end of the heating balance pipeline (9) is connected to the outlet end of the third heat exchanger (4), and the other end is connected to the inlet of the first expansion valve (6), so that when the cooling mode is switched to the heating mode, the refrigerant can flow to the third heat exchanger (4) through the heating balance pipeline (9); In the heating mode of the automatic refrigerant quantity regulating system for the dual cold source unit, the first heat exchanger (2) is a condenser and the second heat exchanger (3) is an evaporator; in the cooling mode of the automatic refrigerant quantity regulating system for the dual cold source unit, the third heat exchanger (4) is a condenser and the first heat exchanger (2) is an evaporator.

2. The automatic refrigerant quantity adjustment system for a dual cold source unit according to claim 1 is characterized in that: It also comprises a dual cold source switching valve (11), and the exhaust end is connected to the inlet of the third heat exchanger (4) via the dual cold source switching valve (11).

3. The automatic refrigerant quantity adjustment system for a dual cold source unit according to claim 1, characterized in that: It also includes a refrigeration check valve (12), the outlet of the third heat exchanger (4) is connected to the seventh port (23) on the first side of the first heat exchanger (2) via the refrigeration check valve (12) and the first expansion valve (6), the refrigeration check valve (12) can allow the refrigerant to flow from the third heat exchanger (4) to the first expansion valve (6), and the refrigeration check valve (12) is arranged in parallel with the second control valve (10).

4. The automatic refrigerant quantity adjustment system for a dual cold source unit according to claim 1, characterized in that: It also includes an economizer (13), one port on the first side of the economizer (13) is selectively connected to the outlet of the third heat exchanger (4) and the sixth port (22), and the other port on the first side of the economizer (13) is connected to the inlet of the first expansion valve (6).

5. The automatic refrigerant quantity adjustment system for a dual cold source unit according to claim 4, characterized in that: The inlet of the second side of the economizer (13) is selectively connected to the outlet of the third heat exchanger (4) and the sixth port (22), and the outlet of the second side of the economizer (13) is connected to the air supply port of the compressor (1).

6. The automatic refrigerant quantity adjustment system for a dual cold source unit according to claim 5, characterized in that: It also includes a second expansion valve (14), which is arranged on an upstream pipeline of the inlet of the second side of the economizer (13).

7. The automatic refrigerant quantity adjustment system for a dual cold source unit according to claim 5, characterized in that: It also includes a first gas-supplementing one-way valve (15), which is arranged on an upstream pipeline of the inlet on the second side of the economizer (13) to limit the refrigerant to flow in one direction only to the inlet on the second side of the economizer (13); And / or, it also includes a second air-supply one-way valve (16), which is arranged on the pipeline between the outlet of the second side of the economizer (13) and the air-supply port to limit the refrigerant to flow to the air-supply port in one direction.

8. The automatic refrigerant quantity adjustment system for a dual cold source unit according to any one of claims 4 to 7, characterized in that: It also comprises a drying filter barrel (17), the inlet of which is selectively connected to the outlet of the third heat exchanger (4) and the sixth port (22), and the economizer (13) is provided in the downstream pipeline of the outlet of the drying filter barrel (17).

9. The automatic refrigerant quantity adjustment system for dual cold source units according to any one of claims 1 to 7, characterized in that: It also comprises an oil return three-way valve (18), the two inlets of which are respectively connected to the oil storage area of ​​the first heat exchanger (2) and the exhaust end, and the outlet of which is connected to the intake end.

10. The automatic refrigerant quantity adjustment system for a dual cold source unit according to claim 2, characterized in that: It also includes an oil separator (19), the inlet of the oil separator (19) being connected to the exhaust end, the refrigerant outlet of the oil separator (19) being connected to the first port (51) and the inlet of the dual cold source switching valve (11), and the oil outlet of the oil separator (19) being connected to the suction end.

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