Water chilling unit system and oil return control method

Abstract

The invention provides a water chilling unit system and an oil return control method. The water chilling unit system comprises a compressor and a heat exchanger, wherein an outlet part of the heat exchanger communicates with the compressor; an inlet of the gas-liquid separator is connected with an exhaust port of the compressor; the gas-liquid separator is provided with a first separation opening which is used for being communicated with an inlet of the heat exchanger. And at least part of the outlet part of the heat exchanger is selectively communicated with or disconnected from the inlet, so that when at least part of the outlet part of the heat exchanger is communicated with the inlet, fluid flowing out of at least part of the outlet part of the heat exchanger exchanges heat with fluid discharged out of the exhaust port. By means of the technical scheme, the technical problem that in the prior art, the refrigerant oil and refrigerant separation efficiency in a water chilling unit system is low can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of water chillers, and in particular to a water chiller system and an oil return control method. Background Art

[0002] At present, for screw chillers using full liquid shell and tube or falling film shell and tube, chilled water is produced through a shell and tube heat exchanger and a screw compressor is used. The refrigerant oil in the shell and tube heat exchanger is used to play the functions of lubrication, sealing, cooling, load control, etc. in the screw compressor.

[0003] However, since refrigeration oil and refrigerant are miscible, in the chiller, the refrigerant in the refrigeration circulation flow path often contains refrigeration oil. In order to avoid oil shortage in the compressor, the conventional technical solution is to set a gas-liquid separator at the exhaust port of the compressor to separate oil and gas, thereby separating the refrigeration oil from the refrigerant gas and returning the refrigeration oil to the compressor. However, due to the high temperature at the exhaust port of the compressor, the high temperature causes the oil droplet diameter of the refrigeration oil to be smaller, which makes it difficult to separate the refrigeration oil from the refrigerant, resulting in the oil separator being unable to completely separate the oil and gas. There is always a part of the refrigeration oil that enters the refrigerant circulation with the refrigerant, which leads to oil shortage in the compressor. At the same time, since there is refrigeration oil in the refrigerant circulation, during the refrigeration cycle, refrigeration oil will accumulate in the shell and tube heat exchanger. The accumulation of refrigeration oil in the heat exchanger affects the heat exchange effect in the cold water shell and tube, and further affects the heat exchange efficiency of the chiller. Summary of the invention

[0004] The main purpose of the present invention is to provide a chiller system and an oil return control method to solve the technical problem of low separation efficiency of refrigeration oil and refrigerant in the chiller system in the prior art.

[0005] In order to achieve the above object, according to one aspect of the present invention, a chiller system is provided, comprising:

[0006] A compressor and a heat exchanger, wherein an outlet of the heat exchanger is in communication with the compressor;

[0007] A gas-liquid separator, the inlet of the gas-liquid separator is connected to the exhaust port of the compressor; the gas-liquid separator has a first separation port, and the first separation port is used to communicate with the inlet of the heat exchanger;

[0008] Wherein, at least part of the outlet of the heat exchanger can be selectively connected or disconnected with the inlet, so that when at least part of the outlet of the heat exchanger is connected with the inlet, at least part of the fluid flowing out through the outlet of the heat exchanger can exchange heat with the fluid discharged through the exhaust port.

[0009] Further, the outlet portion of the heat exchanger comprises a first outlet and a second outlet which are arranged at intervals, the second outlet is located below the first outlet, the first outlet is connected to the compressor, and the second outlet forms at least a part of the outlet portion of the heat exchanger; and / or,

[0010] The chiller system further includes a first valve body, which is disposed at at least a portion of the outlet of the heat exchanger, and is used to control the connection or disconnection between at least a portion of the outlet of the heat exchanger and the inlet; and / or,

[0011] The chiller system further comprises a pump body, which is arranged at least partially at the outlet of the heat exchanger and is used to allow at least partially the fluid flowing out through the outlet of the heat exchanger to pass into the inlet.

[0012] Furthermore, the inlet and the exhaust port are connected through an exhaust pipe; the chiller system also includes:

[0013] A pressure detection member is arranged at the exhaust pipe; and / or,

[0014] A temperature detection element is arranged at the exhaust duct; and / or,

[0015] The liquid level detection component is arranged in the heat exchanger and is used to detect the refrigerant liquid level in the heat exchanger.

[0016] Furthermore, the gas-liquid separator also has a second separation port, which is located below the first separation port and is used to communicate with the compressor; the chiller system also includes:

[0017] an oil filter, disposed at the second separation port, for filtering impurities in the fluid discharged from the second separation port; and / or,

[0018] The second valve body is arranged at the second separation port, and is used to control the connection or disconnection between the second separation port and the compressor.

[0019] Furthermore, the chiller system also includes:

[0020] An ejector, used to communicate with the air intake port of the compressor; the inlet port of the ejector can be selectively connected to or disconnected from the second outlet of the heat exchanger, and the ejection port of the ejector can be selectively connected to or disconnected from the exhaust port;

[0021] Among them, the ejector has an ejection state in which the inlet of the ejector is connected with the second outlet, the ejection port of the ejector is connected with the exhaust port, and the ejector is connected with the air intake port; and a closed state in which the inlet of the ejector is disconnected from the second outlet, and the ejection port of the ejector is disconnected from the exhaust port.

[0022] According to another aspect of the present invention, an oil return control method is provided, which is applicable to the chiller system provided above, and the oil return control method comprises:

[0023] Obtaining at least one of a refrigerant quantity in a heat exchanger of the chiller system and an exhaust gas temperature of a compressor of the chiller system;

[0024] According to at least one of the refrigerant quantity and the exhaust gas temperature, the connection or disconnection between at least a part of the outlet of the heat exchanger and the inlet of the gas-liquid separator of the chiller system is controlled.

[0025] Further, the exhaust gas temperature condition includes the exhaust gas temperature of the compressor; and / or,

[0026] Discharge temperature conditions including compressor discharge superheat; and / or,

[0027] The refrigerant quantity includes the refrigerant liquid level in the heat exchanger.

[0028] Further, according to at least one of the refrigerant quantity and the exhaust gas temperature, controlling the connection or disconnection between at least part of the outlet of the heat exchanger and the inlet of the gas-liquid separator of the chiller system comprises:

[0029] Obtain the refrigerant level in the heat exchanger, the exhaust temperature of the compressor, and the operating time of the compressor;

[0030] Determine whether the chiller system satisfies the first preset judgment condition, the second preset judgment condition, the third preset judgment condition and the fourth preset judgment condition at the same time;

[0031] When the chiller system satisfies the first preset judgment condition, the second preset judgment condition, the third preset judgment condition and the fourth preset judgment condition at the same time, controlling at least a portion of the outlet of the heat exchanger to be connected to the inlet;

[0032] Among them, the first preset judgment condition is that the exhaust temperature of the compressor is greater than the preset temperature value; the second preset judgment condition is that the exhaust superheat of the compressor is greater than the preset superheat; the third preset judgment condition is that the refrigerant liquid level in the heat exchanger is greater than the first preset liquid level value; the fourth preset judgment condition is that the operating time of the compressor is greater than the preset time value.

[0033] Further, judging whether the chiller system satisfies a first preset judgment condition includes: obtaining the exhaust temperature of the compressor within a first preset temperature measurement time range; judging whether the exhaust temperature of the compressor within the first preset temperature measurement time range is greater than a preset temperature value; when the exhaust temperature of the compressor within the first preset temperature measurement time range is greater than a preset temperature value, judging that the chiller system satisfies the first preset judgment condition; and / or,

[0034] Determining whether the chiller system satisfies a second preset judgment condition includes: obtaining the exhaust superheat of the compressor within a second preset temperature measurement time range; determining whether the exhaust superheat of the compressor within the second preset temperature measurement time range is greater than the preset superheat; when the exhaust superheat of the compressor within the second preset temperature measurement time range is greater than the preset superheat, determining that the chiller system satisfies the second preset judgment condition; and / or,

[0035] The ratio of the first preset liquid level value to the height of the storage chamber of the heat exchanger for storing the refrigerant is greater than 0 and less than or equal to 0.3.

[0036] Further, the preset temperature value is greater than or equal to 60° C. and less than or equal to 100° C.; and / or,

[0037] The preset superheat is greater than 0°C and less than or equal to 30°C; and / or,

[0038] The preset duration value is greater than or equal to 30 minutes.

[0039] Furthermore, the oil return control method further includes:

[0040] Obtaining at least one of the refrigerant liquid level in the heat exchanger, the exhaust temperature of the compressor, and the operating state of the compressor;

[0041] Determine whether the chiller system satisfies at least one of a fifth preset judgment condition, a sixth preset judgment condition, and a seventh preset judgment condition;

[0042] When the chiller system satisfies at least one of the fifth preset judgment condition, the sixth preset judgment condition, and the seventh preset judgment condition, controlling at least a portion of the outlet of the heat exchanger to be disconnected from the inlet;

[0043] Among them, the fifth preset judgment condition is that the exhaust superheat of the compressor is less than or equal to the preset superheat; the sixth preset judgment condition is that the refrigerant liquid level in the heat exchanger is less than the second preset liquid level value; and the seventh preset judgment condition is that the compressor is in the off state.

[0044] Further, judging whether the chiller system satisfies the fifth preset judgment condition includes: obtaining the exhaust superheat of the compressor within the third preset temperature measurement time range; judging whether the exhaust superheat of the compressor within the third preset temperature measurement time range is less than or equal to the preset superheat; when the exhaust superheat of the compressor within the third preset temperature measurement time range is less than or equal to the preset superheat, judging that the chiller system satisfies the fifth preset judgment condition; and / or,

[0045] The ratio of the second preset liquid level value to the height of the storage chamber of the heat exchanger for storing the refrigerant is greater than 0 and less than or equal to 0.3.

[0046] By applying the technical solution of the present invention, the oil return efficiency and system reliability of the chiller system can be improved. By establishing an optional connection between the gas-liquid separator and the heat exchanger, when at least part of the outlet of the heat exchanger is connected to the inlet of the gas-liquid separator, the cold of the fluid flowing out of the heat exchanger can be effectively used to exchange heat with the heat of the exhaust gas of the compressor. This heat exchange can promote the reduction of the exhaust temperature, thereby increasing the diameter of the fluid flowing into the inlet of the gas-liquid separator, and then facilitating the improvement of the gas-liquid separation efficiency of the gas-liquid separator, improving the recycling rate of the refrigeration oil, reducing the accumulation of the refrigeration oil in the heat exchanger, thereby improving the heat exchange efficiency and avoiding the failure of the compressor caused by lack of oil. Secondly, by controlling the connection state between the outlet of the heat exchanger and the inlet of the gas-liquid separator, the oil return and heat exchange strategies can be optimized under different operating conditions, thereby achieving the improvement of the overall energy efficiency of the system. In addition, such a setting can also cool the high-temperature refrigerant discharged by the compressor, further improving the condensation effect. Therefore, the technical problem of low separation efficiency of refrigeration oil and refrigerant in the chiller system in the prior art can be solved by the technical solution of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0048] Figure 1 It shows a schematic structural diagram of a chiller system according to the first embodiment of the present invention;

[0049] Figure 2 A schematic diagram of the steps of the oil return control method provided in the second embodiment of the present invention is shown.

[0050] The above drawings include the following reference numerals:

[0051] 10. Compressor; 11. Exhaust port; 12. Intake port; 13. Oil return port;

[0052] 20. heat exchanger; 21. first outlet; 22. second outlet;

[0053] 30. gas-liquid separator; 31. first separation port; 32. second separation port; 33. inlet;

[0054] 40. a first valve body;

[0055] 50. Pump body;

[0056] 60. Pressure testing parts;

[0057] 70. Temperature detection parts;

[0058] 80. Second valve body;

[0059] 90. Ejector;

[0060] 100, third valve body;

[0061] 110, fourth valve body;

[0062] 120. Oil filter;

[0063] 130. Air heat exchanger;

[0064] 140. Electronic expansion valve;

[0065] 150. Exhaust duct. DETAILED DESCRIPTION

[0066] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0067] like Figure 1 As shown, the first embodiment of the present invention provides a chiller system, which includes a compressor 10, a heat exchanger 20 and a gas-liquid separator 30. The outlet of the heat exchanger 20 is connected to the compressor 10. The inlet 33 of the gas-liquid separator 30 is connected to the exhaust port 11 of the compressor 10; the gas-liquid separator 30 has a first separation port 31, and the first separation port 31 is used to communicate with the inlet of the heat exchanger 20. Among them, at least part of the outlet of the heat exchanger 20 can be selectively connected or disconnected with the inlet 33, so that when at least part of the outlet of the heat exchanger 20 is connected with the inlet 33, at least part of the fluid flowing out of the outlet of the heat exchanger 20 is exchanged with the fluid discharged through the exhaust port 11.

[0068] The chiller system provided by the first embodiment of the present invention can firstly improve the oil return efficiency and system reliability of the chiller system. By establishing an optional connection between the gas-liquid separator 30 and the heat exchanger 20, when at least part of the outlet of the heat exchanger 20 is connected to the inlet 33 of the gas-liquid separator 30, the cold of the fluid flowing out of the heat exchanger 20 can be effectively used to exchange heat with the heat of the exhaust gas of the compressor 10. This heat exchange can promote the reduction of the exhaust gas temperature, thereby increasing the diameter of the fluid flowing into the inlet 33 of the gas-liquid separator 30, thereby facilitating the improvement of the gas-liquid separation efficiency of the gas-liquid separator 30, improving the recycling rate of the refrigeration oil, and reducing the accumulation of the refrigeration oil in the heat exchanger 20, thereby improving the heat exchange efficiency and avoiding the failure of the compressor 10 caused by lack of oil. Secondly, by controlling the connection state between the outlet of the heat exchanger 20 and the inlet 33 of the gas-liquid separator 30, the oil return and heat exchange strategies can be optimized under different operating conditions, thereby achieving the improvement of the overall energy efficiency of the system. In addition, such a configuration can also cool the high-temperature refrigerant discharged from the compressor 10, further improving the condensation effect. Therefore, the chiller system provided by this embodiment can solve the technical problem of low separation efficiency of refrigeration oil and refrigerant in the chiller system in the prior art.

[0069] Specifically, the heat exchanger 20 is a shell and tube heat exchanger, and has a first heat exchange part for accommodating a refrigerant and a second heat exchange part for accommodating water.

[0070] Specifically, the chiller system also includes an air heat exchanger 130, and the first separation port 31 is connected to the air heat exchanger 130. The chiller system also includes an electronic expansion valve 140, the inlet of the electronic expansion valve 140 is connected to the air heat exchanger 130, and the outlet of the electronic expansion valve 140 is connected to the heat exchanger 20. With such a structural arrangement, by connecting the first separation port 31 of the gas-liquid separator 30 with the air heat exchanger 130, the high-temperature and high-pressure refrigerant gas separated from the exhaust gas of the compressor 10 can be further cooled, its temperature can be reduced, and the condensation efficiency can be improved. The use of the electronic expansion valve 140 realizes the precise control of the refrigerant flow rate, and the flow rate and pressure of the refrigerant can be automatically adjusted according to the changes in the system load, thereby optimizing the energy efficiency ratio and operation stability of the refrigeration system.

[0071] Specifically, the refrigeration circulation flow path of the chiller system includes: the high-temperature and high-pressure gas (carrying refrigerant oil) discharged from the compressor 10 enters the gas-liquid separator 30 through the inlet 33 of the gas-liquid separator 30 for oil-gas separation, and most of the refrigerant oil is separated by the gas-liquid separator 30. The high-temperature and high-pressure refrigerant gas continues to enter the air heat exchanger 130 along the first separation port 31 for heat exchange, condenses into a high-pressure and medium-temperature refrigerant liquid in the air heat exchanger 130, and enters the shell and tube heat exchanger through the electronic expansion valve 140 (EXV) for throttling and pressure reduction, absorbs the heat of water to reduce the water temperature, and thus produces chilled water. The refrigerant absorbs heat and evaporates, and enters the air intake port 12 of the compressor 10 to complete the refrigerant cycle.

[0072] Specifically, the inlet 33 is connected to the exhaust port 11 through the exhaust pipe 150. At least part of the outlet portion of the heat exchanger 20 can be selectively connected or disconnected with the exhaust pipe 150. With such a structural arrangement, the extended length of the exhaust pipe 150 can be utilized to achieve sufficient heat exchange between the coldness of the fluid flowing out of the heat exchanger 20 and the heat of the exhaust gas of the compressor 10 in the exhaust pipe 150, thereby further promoting the reduction of the exhaust temperature, and then increasing the diameter of the fluid flowing into the inlet 33 of the gas-liquid separator 30, further facilitating the improvement of the gas-liquid separation efficiency of the gas-liquid separator 30, improving the recycling rate of the refrigeration oil, and reducing the accumulation of the refrigeration oil in the heat exchanger 20, thereby improving the heat exchange efficiency and avoiding the failure of the compressor 10 caused by lack of oil.

[0073] Specifically, the outlet portion of the heat exchanger 20 includes a first outlet 21 and a second outlet 22 which are arranged at intervals, the second outlet 22 is located below the first outlet 21, the first outlet 21 is connected to the compressor 10, and the second outlet 22 forms at least part of the outlet portion of the heat exchanger 20. With such a structural arrangement, by placing the second outlet 22 below the first outlet 21, it is helpful to utilize the gravity effect so that the refrigerant containing the refrigeration oil flows out from the second outlet 22 first, and the oil separation and oil return are performed, thereby improving the efficiency of refrigeration oil recovery.

[0074] Specifically, the chiller system further includes a first valve body 40, which is disposed at at least a portion of the outlet of the heat exchanger 20, and is used to control the connection or disconnection between at least a portion of the outlet of the heat exchanger 20 and the inlet 33. With such a structural arrangement, the introduction of the first valve body 40 provides flexibility in flow control, and can intelligently adjust the distribution of the refrigerant flow according to the operating state and requirements of the system, avoiding unnecessary energy waste, and preventing the liquid refrigerant from directly entering the compressor 10, thereby reducing the risk of liquid compression.

[0075] Specifically, the chiller system further includes a pump body 50, which is disposed at least partially at the outlet of the heat exchanger 20, and is used to allow at least part of the fluid flowing out of the outlet of the heat exchanger 20 to flow into the inlet 33. With such a structural arrangement, the use of the pump body 50 enhances the initiative of refrigeration oil recovery, and by pumping the refrigerant mixture containing refrigeration oil into the inlet 33, the reliability of oil return is improved, and the recycling of the refrigerant is promoted.

[0076] Specifically, the pump body 50 is a booster pump.

[0077] Specifically, the first valve body 40 and the pump body 50 are opened and stopped at the same time. In this way, the synchronous start and stop of the first valve body 40 and the pump body 50 ensures that when it is necessary to pump back the oil-containing fluid from the heat exchanger 20, the pump body 50 works immediately, and the first valve body 40 is opened at the same time, forming a continuous and reliable flow path, so that the refrigerant oil in the heat exchanger 20 is promptly and effectively pumped back to the gas-liquid separator 30, avoiding the accumulation of refrigerant oil in the heat exchanger 20, affecting the heat exchange efficiency, and preventing the compressor 10 from having poor lubrication due to insufficient oil, thereby improving the operating stability of the system and the reliability of the compressor 10.

[0078] Specifically, the inlet 33 is connected to the exhaust port 11 through an exhaust pipe 150. The chiller system also includes a pressure detection component 60, which is arranged at the exhaust pipe 150. With such a structural arrangement, the arrangement of the pressure detection component 60 realizes real-time monitoring of the exhaust pressure of the compressor 10, which helps to timely adjust the operating state of the system, optimize the condensation conditions, and provide data support for the protection and fault diagnosis of the system. In addition, the pressure detection component 60 is arranged at the exhaust pipe 150, and can also monitor the gas pressure after the exhaust gas of the compressor 10 is mixed with the fluid flowing out of the heat exchanger 20, so as to facilitate the real-time monitoring of the system status.

[0079] Specifically, the detection range of the pressure detection element 60 is 0 kPa to 3550 kPa (including 0 kPa and 3550 kPa).

[0080] Specifically, the inlet 33 is connected to the exhaust port 11 through an exhaust pipe 150. The chiller system also includes a temperature detection component 70, which is arranged at the exhaust pipe 150. With such a structural arrangement, the installation of the temperature detection component 70 enables the system to accurately grasp the temperature of the exhaust gas of the compressor 10, which is crucial for optimizing the recycling of the refrigerant, improving the condensation efficiency and preventing the compressor 10 from overheating, and also provides an ideal temperature control condition for the separation of the refrigeration oil and the refrigerant. In addition, the temperature detection component 70 is arranged at the exhaust pipe 150, and can also monitor the temperature of the exhaust gas of the compressor 10 mixed with the fluid flowing out of the heat exchanger 20, so as to facilitate the real-time status of the monitoring system.

[0081] Specifically, the detection range of the temperature detection member 70 is 0° C. to 100° C. (inclusive).

[0082] Specifically, the inlet 33 is connected to the exhaust port 11 through the exhaust pipe 150. The chiller system also includes a liquid level detection component, which is arranged in the heat exchanger 20 and is used to detect the refrigerant liquid level in the heat exchanger 20. With such a structural arrangement, the liquid level change of the refrigerant in the heat exchanger 20 can be accurately monitored, which is of great value for preventing refrigerant accumulation, avoiding liquid compression of the compressor 10, and optimizing the refrigerant circulation path. At the same time, the liquid level information is also a key basis for controlling the pump body 50 and the first valve body 40, which helps to improve the overall operation efficiency and safety of the system.

[0083] In this embodiment, the gas-liquid separator 30 also has a second separation port 32, which is located below the first separation port 31 and is used to communicate with the compressor 10. The chiller system also includes an oil filter 120, which is arranged at the second separation port 32, and the oil filter 120 is used to filter impurities in the fluid discharged from the second separation port 32. With such a structural setting, the design of the second separation port 32 makes full use of the principle of gravity, effectively separates the refrigerant oil in the condensed liquid, and makes it flow through the second separation port 32 preferentially, thereby improving the refrigerant oil reflux efficiency. The setting of the oil filter 120 can filter out impurities mixed in the condensed liquid, such as metal chips, dust, etc., to prevent these impurities from entering the compressor 10, protect the normal operation of the compressor 10, extend the system life, and ensure the quality of the refrigerant oil, thereby optimizing the lubrication, cooling and sealing effects of the compressor 10.

[0084] Specifically, the second separation port 32 is used to communicate with the air intake port 12 of the compressor 10 or the oil return port 13 of the compressor 10. With such a structural setting, two optional types are provided, which increases the flexibility of the system.

[0085] In this embodiment, the gas-liquid separator 30 also has a second separation port 32, which is located below the first separation port 31 and is used to communicate with the compressor 10. The chiller system also includes a second valve body 80, which is arranged at the second separation port 32, and the second valve body 80 is used to control the connection or disconnection between the second separation port 32 and the compressor 10. With such a structural arrangement, the introduction of the second valve body 80 provides controllability of the flow path from the second separation port 32 to the compressor 10, and can intelligently adjust the refrigeration oil reflux according to the system operating status and needs, avoid fluid reflux when it is not needed, reduce energy loss, and also prevent liquid refrigerant from entering the compressor 10 under inappropriate conditions, reduce the risk of liquid compression, and improve the safety and efficiency of system operation.

[0086] Specifically, the second valve body 80 opens and stops at the same time as the compressor 10. In this way, the synchronous start and stop of the second valve body 80 and the compressor 10 ensures that when the compressor 10 starts, the second valve body 80 also opens at the same time, so that the refrigerant oil filtered at the second separation port 32 of the gas-liquid separator 30 can flow back to the compressor 10 in time, ensuring that there is enough refrigerant oil inside the compressor 10 for lubrication, cooling and sealing, and preventing the compressor 10 from being damaged due to lack of oil when starting. At the same time, when the compressor 10 is turned off, the second valve body 80 is closed accordingly to prevent the refrigerant or oil from flowing back, protect the system from unnecessary pressure fluctuations and energy waste, and improve the safety and energy efficiency of the system.

[0087] Specifically, the chiller system further includes an ejector 90, which is used to communicate with the air intake port 12 of the compressor 10; the inlet of the ejector 90 can be selectively connected or disconnected with the second outlet 22 of the heat exchanger 20, and the ejection port of the ejector 90 can be selectively connected or disconnected with the exhaust port 11. The ejector 90 has an ejection state in which the inlet of the ejector 90 is connected with the second outlet 22, the ejection port of the ejector 90 is connected with the exhaust port 11, and the ejector 90 is connected with the air intake port 12, and a closed state in which the inlet of the ejector 90 is disconnected from the second outlet 22, and the ejection port of the ejector 90 is disconnected from the exhaust port 11. With such a structural setting, the design of the ejector 90 can utilize the kinetic energy and pressure difference of the exhaust of the compressor 10 to guide the liquid containing the refrigerant oil from the second outlet 22 of the heat exchanger 20 back to the air intake port 12 of the compressor. This process does not require an additional power source, saving energy consumption, and effectively solves the problem of accumulation of refrigerant oil in the heat exchanger 20, improves the recovery rate and heat exchange efficiency of the refrigerant oil, ensures good lubrication and cooling conditions of the compressor 10, and thus improves the reliability of the compressor. Secondly, this controllable connectivity enables the ejector 90 to switch to an ejection state or a closed state under different operating conditions. In the ejection state, the inlet of the ejector 90 is connected to the second outlet 22, and the ejection port is connected to the exhaust port 11, so as to realize the efficient withdrawal of the refrigerant oil; in the closed state, the inlet and the ejection port are disconnected, avoiding unnecessary fluid reflux, protecting the compressor from direct impact of the liquid refrigerant, and reducing the risk of liquid compression. This intelligent flow path control optimizes the operating efficiency and safety of the system under different working conditions.

[0088] Specifically, the chiller system also includes a third valve body 100, which is arranged at the oil discharge port of the heat exchanger 20. The third valve body 100 is used to control the connection or disconnection between the inlet of the ejector 90 and the second outlet 22 of the heat exchanger 20. With such a structural arrangement, the introduction of the third valve body 100 provides controllability for the flow path between the ejector 90 and the heat exchanger 20, and can intelligently control the recovery process of the oil-containing refrigerant fluid according to the needs of the system. When oil return is required, the third valve body 100 is opened to allow the oil-containing fluid to smoothly enter the ejector 90, thereby improving the oil return efficiency; when the system does not need to recover the refrigeration oil or is in an abnormal operating condition, the third valve body 100 is closed to prevent unnecessary fluid flow, avoid energy consumption and system fluctuations, and also ensure the safe operation of the equipment.

[0089] Specifically, the chiller system further includes a fourth valve body 110, which is arranged at the exhaust port 11, and is used to control the connection or disconnection between the ejector port of the ejector 90 and the exhaust port 11. In this way, the arrangement of the fourth valve body 110 ensures the flow path control between the ejector 90 and the exhaust port 11, and can timely open or close the ejector port according to the operating state of the compressor 10 and the system requirements, and utilizes the kinetic energy and pressure of the exhaust of the compressor 10 to efficiently guide the oil-containing refrigerant in the heat exchanger 20 back to the compressor suction port 12, thereby optimizing the recovery path of the refrigeration oil, reducing the energy loss in the oil return process, and improving the overall energy efficiency of the system. At the same time, in the non-oil return state or when the compressor 10 is not in operation, the fourth valve body 110 can be closed to avoid unnecessary fluid circulation in the system, protect the compressor 10 from direct impact of the liquid refrigerant, reduce the risk of liquid compression, and enhance the operating safety and stability of the system.

[0090] Specifically, the third valve body 100 and the fourth valve body 110 are opened and stopped at the same time. Specifically, the third valve body 100 and the fourth valve body 110 are opened periodically together. With such a structural setting, the synchronous periodic operation of the third valve body 100 and the fourth valve body 110 realizes the automation and intelligence of the refrigeration oil recovery, and can start the refrigeration oil recovery process regularly and automatically during the operation of the system. This periodic opening strategy not only ensures the timely recovery of the refrigeration oil, avoids the long-term accumulation in the heat exchanger 20, affects the heat exchange efficiency and the normal operation of the equipment, but also avoids the system energy waste and unstable operation caused by continuous oil return, ensuring the efficient and stable operation of the system under various working conditions. The periodic opening strategy can also be optimized and adjusted according to the system working conditions, further improving the energy efficiency and operational flexibility of the system. Thirdly, such a setting can also reduce the risk of liquid hammer. In a conventional refrigeration system, liquid refrigerant directly enters the compressor 10, which may cause liquid hammer and damage the compressor 10. By establishing a controllable communication path, it is possible to avoid the suction of liquid, thereby reducing the risk of liquid hammer and increasing the safety and operational stability of the system.

[0091] Specifically, the first valve body 40 , the second valve body 80 , the third valve body 100 and the fourth valve body 110 are all solenoid valves.

[0092] Specifically, in order to avoid interfering with the communication between at least part of the outlet portion of the heat exchanger 20 and the inlet 33 of the gas-liquid separator 30 , when the first valve body 40 is opened, the third valve body 100 and the fourth valve body 110 are closed.

[0093] like Figure 2 As shown, embodiment 2 of the present invention provides an oil return control method, which is applicable to the chiller system provided in embodiment 1, and the oil return control method includes: obtaining at least one of the refrigerant quantity in the heat exchanger 20 of the chiller system and the exhaust temperature of the compressor 10 of the chiller system; and controlling the connection or disconnection between at least part of the outlet of the heat exchanger 20 and the inlet 33 of the gas-liquid separator of the chiller system according to at least one of the refrigerant quantity and the exhaust temperature.

[0094] By adopting the oil return control method provided in the second embodiment of the present invention, according to the monitored refrigerant amount and / or exhaust temperature, the oil return control method can intelligently control the connection state between the outlet of the heat exchanger 20 and the inlet 33 of the gas-liquid separator 30, and adjust the oil return path and timing of the refrigeration oil. In this way, when the refrigerant amount is sufficient and / or the exhaust temperature is high, the relevant flow path can be used to reduce the temperature of the high-temperature refrigerant discharged by the compressor 10, thereby improving the condensation effect. At the same time, the cold amount of the fluid flowing out of the heat exchanger 20 and the heat of the exhaust gas of the compressor 10 can be effectively used for heat exchange. This heat exchange can promote the reduction of the exhaust temperature, thereby increasing the diameter of the fluid flowing into the inlet 33 of the gas-liquid separator 30, and then facilitating the improvement of the gas-liquid separation efficiency of the gas-liquid separator 30, improving the recycling rate of the refrigeration oil, reducing the accumulation of the refrigeration oil in the heat exchanger 20, thereby improving the heat exchange efficiency and avoiding the failure of the compressor 10 caused by lack of oil, promoting the recovery of refrigeration oil, and avoiding the performance of the compressor 10 affected by lack of oil. When the amount of refrigerant is insufficient or the exhaust temperature is low, the refrigeration cycle of the system is prioritized to avoid affecting the heat exchange in the heat exchanger 20, thereby ensuring the high efficiency and safety of the system operation. The oil return control method can adjust the recovery strategy of the refrigeration oil according to different operating conditions, enhance the adaptability of the system to different working conditions, enable the chiller system to respond to changing environments and needs more flexibly, and improve the overall performance and operating efficiency of the system. Therefore, the oil return control method provided in this embodiment can solve the technical problem of low separation efficiency of refrigeration oil and refrigerant in the chiller system in the prior art.

[0095] Specifically, the exhaust temperature condition includes the exhaust temperature of the compressor 10. In this way, the timing of connecting or disconnecting at least part of the outlet portion of the heat exchanger 20 and the inlet 33 of the chiller system can be determined by the size of the exhaust temperature. Real-time monitoring of the exhaust temperature of the compressor 10 can accurately evaluate the heat load state and operating efficiency of the compressor 10. High exhaust temperature is often associated with heat accumulation inside the compressor 10 and a decrease in the refrigerant cycle efficiency. By monitoring the exhaust temperature, potential problems in system operation, such as insufficient refrigerant and poor oil return, can be discovered in time, so that corresponding control measures can be taken to improve the oil return efficiency of the refrigeration oil, reduce the exhaust temperature of the compressor 10, avoid equipment failures caused by overheating of the compressor 10, and improve the operating safety and long-term reliability of the chiller system.

[0096] Specifically, the exhaust temperature condition includes the exhaust superheat of the compressor 10. It should be noted that the exhaust superheat is equal to the difference between the exhaust temperature and the saturation temperature corresponding to the exhaust pressure. With such a setting, the exhaust superheat has a direct impact on the oil droplet diameter. The larger the exhaust superheat, the smaller the oil droplet diameter, and the separation efficiency of the gas-liquid separator 30 for the refrigerant oil will also decrease. Therefore, the exhaust superheat is an important indicator for evaluating the refrigerant cycle efficiency and refrigerant oil recovery performance of the compressor 10. Too high or too low exhaust superheat may affect the stable operation of the system. By monitoring the exhaust superheat, the system can intelligently judge the timing and amount of refrigerant oil recovery, ensure that when the exhaust superheat reaches the threshold, the refrigerant oil recovery process is started, effectively reduce the exhaust superheat, avoid overheating of the compressor 10, and improve the system operation efficiency. At the same time, the optimized exhaust superheat control strategy helps to improve the lubrication conditions of the compressor 10, and improve the reliability and service life of the compressor 10.

[0097] Specifically, the refrigerant quantity includes the refrigerant liquid level in the heat exchanger 20. With such a setting, the refrigerant liquid level in the heat exchanger 20 is monitored, so that the refrigerant quantity in the system can be timely grasped, so as to avoid that when the refrigerant quantity in the heat exchanger 20 is insufficient, at least part of the outlet of the heat exchanger 20 is connected with the inlet 33 of the chiller system, thereby affecting the normal refrigeration cycle flow path of the system.

[0098] Specifically, according to at least one of the refrigerant quantity and the exhaust temperature, the method for controlling the connection or disconnection between at least part of the outlet of the heat exchanger 20 and the inlet 33 of the gas-liquid separator of the chiller system includes: obtaining the refrigerant liquid level in the heat exchanger 20, the exhaust temperature of the compressor 10 and the running time of the compressor 10; judging whether the chiller system satisfies the first preset judgment condition, the second preset judgment condition, the third preset judgment condition and the fourth preset judgment condition at the same time; and controlling at least part of the outlet of the heat exchanger 20 to be connected with the inlet when the chiller system satisfies the first preset judgment condition, the second preset judgment condition, the third preset judgment condition and the fourth preset judgment condition at the same time. Among them, the first preset judgment condition is that the exhaust temperature of the compressor 10 is greater than the preset temperature value; the second preset judgment condition is that the exhaust superheat of the compressor 10 is greater than the preset superheat; the third preset judgment condition is that the refrigerant liquid level in the heat exchanger 20 is greater than the first preset liquid level value; and the fourth preset judgment condition is that the running time of the compressor 10 is greater than the preset time value. With such a setting, by obtaining the refrigerant liquid level in the heat exchanger 20, the exhaust temperature of the compressor 10 and its operating time in real time, the control method can perform comprehensive analysis and decision-making based on multi-dimensional data, and realize accurate control of the connection state between the outlet of the heat exchanger 20 and the inlet 33. This ability of real-time monitoring and intelligent decision-making improves the adaptability and response speed of the system, and ensures the efficient and stable operation of the system under various working conditions. Among them, the first preset judgment condition sets the threshold value of the exhaust temperature of the compressor 10, so that when the exhaust temperature of the compressor 10 is high, the cooling effect of the fluid flowing out of the heat exchanger 20 can be used to reduce the exhaust temperature of the compressor 10, thereby improving the reliability and operating life of the compressor. The second preset judgment condition focuses on the exhaust superheat. When the exhaust superheat is greater than the preset superheat, it indicates that the separation efficiency of the refrigeration oil and the refrigerant gas in the system is reduced. At this time, starting the refrigeration oil recovery process can effectively improve the recovery efficiency of the refrigeration oil from the heat exchanger 20 to the compressor 10, ensure that there is sufficient refrigeration oil inside the compressor 10 for lubrication and cooling, and improve the operating efficiency and overall performance of the chiller system. The third preset judgment condition sets the threshold of the refrigerant liquid level in the heat exchanger 20. When the refrigerant liquid level is higher than the first preset liquid level value, the refrigeration oil recovery process is started, which can avoid affecting the normal refrigeration cycle of the system due to the low refrigerant liquid level, optimize the system operation state, and improve the system energy efficiency and equipment protection. The fourth preset judgment condition sets the compressor 10 operation time threshold. Only when the compressor 10 operation time is greater than the preset time value, the system will consider starting the refrigeration oil recovery process, avoiding the interference of system instability in the initial startup of the compressor 10, ensuring that the oil return process is started when the system reaches a stable operating state, improving the efficiency and reliability of oil return, and reducing unnecessary energy consumption.By simultaneously satisfying four preset judgment conditions to start the connection between the outlet of the heat exchanger 20 and the inlet 33, the control method realizes the intelligent linkage between the refrigerant oil recovery and the system operation status, which not only improves the efficiency of the refrigerant oil recovery and the operation safety of the compressor 10, but also optimizes the refrigerant cycle, improves the heat exchange efficiency of the heat exchanger 20, reduces the overall energy consumption of the system, and enhances the overall performance and operation stability of the chiller system.

[0099] Specifically, the method for judging whether the chiller system meets the first preset judgment condition includes: obtaining the exhaust temperature of the compressor 10 within the first preset temperature measurement time range; judging whether the exhaust temperature of the compressor 10 is greater than the preset temperature value within the first preset temperature measurement time range; when the exhaust temperature of the compressor 10 within the first preset temperature measurement time range is greater than the preset temperature value, judging that the chiller system meets the first preset judgment condition. With such a method, this judgment condition ensures that the system can respond quickly and take action when the compressor 10 is in a high heat load state by detecting the exhaust temperature of the compressor 10 within the first preset temperature measurement time. If the exhaust temperature continues to be higher than the preset temperature value within the set time period, the system will consider that the first preset judgment condition is met, thereby starting the refrigeration oil recovery process, using the circulating cooling effect of the refrigeration oil to reduce the exhaust temperature of the compressor 10, avoiding the performance degradation and equipment failure of the compressor 10 caused by the excessively high exhaust temperature, and improving the operating stability and overall efficiency of the compressor 10. Such a setting avoids the influence of the unstable fluctuation of the exhaust temperature on the judgment of the first preset judgment condition.

[0100] Specifically, the method for judging whether the chiller system meets the second preset judgment condition includes: obtaining the exhaust superheat of the compressor 10 within the second preset temperature measurement time range; judging whether the exhaust superheat of the compressor 10 is greater than the preset superheat within the second preset temperature measurement time range; when the exhaust superheat of the compressor 10 within the second preset temperature measurement time range is greater than the preset superheat, judging that the chiller system meets the second preset judgment condition. In this way, the second preset judgment condition ensures the optimization of the refrigerant circulation and the refrigeration oil separation efficiency by monitoring the exhaust superheat of the compressor 10. When the exhaust superheat is continuously greater than the preset superheat within the second preset temperature measurement time, the system will consider that the second preset judgment condition is met and automatically start the refrigeration oil recovery process. High exhaust superheat indicates that the separation efficiency of the refrigeration oil and the refrigerant in the system is reduced. By timely recovering the refrigeration oil and optimizing the circulation path, the oil return rate of the refrigeration oil can be improved, the lubrication condition of the compressor 10 can be improved, and the exhaust superheat can be reduced, the refrigerant circulation can be optimized, and the refrigeration efficiency and operation stability of the chiller system can be improved. Such a setting avoids the influence of unstable fluctuations of exhaust temperature and exhaust pressure on the determination of the second preset determination condition.

[0101] Specifically, the ratio of the first preset liquid level value to the height of the storage chamber of the heat exchanger 20 for storing the refrigerant is greater than 0 and less than or equal to 0.3. With such a setting, the liquid level of the refrigerant in the heat exchanger 20 can be effectively controlled to avoid the heat exchanger 20 being connected to the inlet 33 when the refrigerant in the heat exchanger 20 is insufficient, thereby affecting the normal refrigeration process of the system. At the same time, it also avoids the poor refrigeration oil reflux and the decrease in heat exchange efficiency caused by the excessively high liquid level, and prevents the risk of oil shortage in the compressor 10 caused by the excessively low liquid level. This setting ensures the balance of the circulation of the refrigeration oil and the refrigerant under different operating conditions of the system, optimizes the heat exchange efficiency of the heat exchanger 20, reduces the risk of liquid compression, and improves the overall performance and operating safety of the chiller system.

[0102] In this embodiment, the preset temperature value is greater than or equal to 60°C and less than or equal to 100°C. In this way, by comparing with the preset temperature value, it is possible to determine whether the system is in a high heat load state, trigger the refrigeration oil recovery process, and reduce the exhaust temperature of the compressor 10 to prevent the compressor 10 from overheating and causing performance degradation or equipment failure. The intelligent control of this temperature threshold improves the system operation stability and long-term reliability, while optimizing the system's refrigeration efficiency and energy efficiency ratio.

[0103] In this embodiment, the preset superheat is greater than 0° C. and less than or equal to 30° C. In this way, the separation efficiency of the gas-liquid separator 30 for the refrigeration oil and the refrigerant gas can be judged by comparison with the preset superheat, so that the circulation path of the refrigeration oil and the refrigerant gas can be optimized, the oil return rate of the refrigeration oil can be increased, the lubrication state of the compressor 10 can be improved, and the exhaust superheat can be reduced, the refrigerant cycle can be optimized, the refrigeration efficiency and overall performance of the chiller system can be improved, the equipment maintenance cost can be reduced, and the service life of the equipment can be extended.

[0104] In this embodiment, the preset time value is greater than or equal to 30 minutes. In this way, it is ensured that the oil return process is started only after the compressor 10 reaches a stable operating state, avoiding energy waste and equipment impact caused by oil return operation in the initial startup or under unstable conditions.

[0105] Specifically, the oil return control method further includes: obtaining at least one of the refrigerant liquid level in the heat exchanger 20, the exhaust temperature of the compressor 10, and the operating state of the compressor 10; judging whether the chiller system satisfies at least one of the fifth preset judgment condition, the sixth preset judgment condition, and the seventh preset judgment condition; when the chiller system satisfies at least one of the fifth preset judgment condition, the sixth preset judgment condition, and the seventh preset judgment condition, controlling at least part of the outlet of the heat exchanger 20 to be disconnected from the inlet 33; wherein the fifth preset judgment condition is that the exhaust superheat of the compressor 10 is less than or equal to the preset superheat; the sixth preset judgment condition is that the refrigerant liquid level in the heat exchanger 20 is less than the second preset liquid level value, and the seventh preset judgment condition is that the compressor 10 is in the off state. With such a setting, by real-time monitoring of the exhaust superheat of the compressor 10, the refrigerant liquid level of the heat exchanger 20, and the operating state of the compressor 10, the intelligent linkage between the refrigeration oil recovery process and the system operating state is realized. When one of the fifth, sixth or seventh preset judgment conditions is met, the system can automatically adjust the connectivity of the outlet of the heat exchanger 20, which not only improves the efficiency of refrigeration oil recovery, optimizes the circulation and distribution of refrigeration oil, but also avoids potential risks in system operation, such as overheating of the compressor 10, abnormal liquid level and equipment failure, etc., thereby improving the overall performance and operational safety of the chiller system. Among them, for the fifth preset judgment condition, by obtaining the exhaust temperature of the compressor 10 and detecting the exhaust superheat of the compressor 10, when it is less than or equal to the preset superheat, the system will determine that the current separation efficiency of the refrigeration oil and the refrigerant gas has reached a better level, and there is no need to start the refrigeration oil recovery process additionally. The setting of this condition avoids the unnecessary start of the refrigeration oil recovery process, which not only reduces the energy consumption of the system operation, but also optimizes the circulation and distribution of the refrigeration oil, maintains the efficient operation of the system at a lower energy consumption, and improves the economy and reliability of the chiller system. For the sixth preset judgment condition, by obtaining the refrigerant liquid level in the heat exchanger 20 and monitoring the refrigerant liquid level in the heat exchanger 20, when the liquid level is less than the second preset liquid level value, the system will automatically disconnect the connection between the outlet of the heat exchanger 20 and the inlet 33 to prevent the refrigerant liquid level from being too low, causing the heat exchanger 20 to be unable to produce chilled water normally. This liquid level control strategy not only avoids the wear and performance degradation of the compressor 10 caused by lack of oil, but also ensures the efficient heat exchange and system energy efficiency of the heat exchanger 20, reduces the risk of liquid compression and equipment failure, and improves the operating safety and stability of the chiller system. For the seventh preset judgment condition, by obtaining the operating status of the compressor 10, when the compressor 10 is in the off state, the system will automatically disconnect the connection between the outlet of the heat exchanger 20 and the inlet 33.This state control strategy ensures that when the compressor 10 is not working, the refrigeration oil circulation and oil return process can be automatically stopped, avoiding unnecessary energy consumption. At the same time, it reduces the maintenance complexity of the system when it is not operating, improves the energy efficiency and maintenance convenience of the chiller system, and reduces operating costs.

[0106] Specifically, the method for determining whether the chiller system meets the fifth preset judgment condition includes: obtaining the exhaust superheat of the compressor 10 within the third preset temperature measurement time range; determining whether the exhaust superheat of the compressor 10 within the third preset temperature measurement time range is less than or equal to the preset superheat; when the exhaust superheat of the compressor 10 within the third preset temperature measurement time range is less than or equal to the preset superheat, determining that the chiller system meets the fifth preset judgment condition. By adopting such a method, by obtaining the exhaust superheat of the compressor 10 within the third preset temperature measurement time range, and determining whether it is less than or equal to the preset superheat, refined monitoring of the system status is achieved. When the system meets the fifth preset judgment condition, it indicates that the separation efficiency of the refrigeration oil and the refrigerant gas of the compressor 10 has reached a better level under the current working conditions, and no additional refrigeration oil recovery process is required. The setting of this condition avoids unnecessary refrigeration oil recovery operations, reduces the energy consumption of the system, and at the same time optimizes the circulation path of the refrigeration oil, ensuring that the compressor 10 operates under appropriate exhaust superheat conditions, improving its operating efficiency and stability, and reducing the risk of equipment failure. It is a key technical means to achieve efficient and safe operation of the system.

[0107] Specifically, the first preset temperature measurement time is greater than 0s and less than or equal to 180s. The second preset temperature measurement time is greater than 0s and less than or equal to 180s. The third preset temperature measurement time is 10s. In this way, it is possible to avoid the short-term fluctuation of the detection result from affecting the judgment of the preset judgment condition.

[0108] Specifically, the ratio of the second preset liquid level value to the height of the storage chamber of the heat exchanger 20 for storing the refrigerant is greater than 0 and less than or equal to 0.3. In this way, the refrigerant liquid level in the heat exchanger 20 is ensured to be maintained at an appropriate level, avoiding the problem of oil shortage in the compressor 10 and the problem of insufficient refrigerant in the heat exchanger 20 caused by the low refrigerant liquid level. At the same time, this liquid level control strategy ensures sufficient refrigeration oil reflux space, improves the refrigeration oil recovery efficiency, optimizes the circulation and distribution of refrigeration oil, ensures the internal lubrication and cooling effect of the compressor 10, improves the heat exchange efficiency of the heat exchanger 20, reduces the risk of liquid compression, optimizes the refrigerant cycle, thereby improving the overall performance and operational safety of the chiller system, and is a key technical measure to achieve efficient and stable refrigeration of the system.

[0109] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: effectively reduce the refrigerant oil accumulated in the cold water shell and tube, lower the exhaust temperature and reduce the amount of refrigerant oil entering the refrigerant cycle with the refrigerant, and effectively reduce the risk of liquid inhalation in the compressor.

[0110] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0111] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0112] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0113] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0114] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0115] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A chiller system, characterized in that: include: A compressor (10) and a heat exchanger (20), wherein an outlet of the heat exchanger (20) is in communication with the compressor (10); a gas-liquid separator (30), wherein the inlet (33) of the gas-liquid separator (30) is connected to the exhaust port (11) of the compressor (10); the gas-liquid separator (30) has a first separation port (31), and the first separation port (31) is used to communicate with the inlet of the heat exchanger (20); In which, at least part of the outlet portion of the heat exchanger (20) can be selectively connected to or disconnected from the inlet (33), so that when at least part of the outlet portion of the heat exchanger (20) is connected to the inlet (33), at least part of the fluid flowing out through the outlet portion of the heat exchanger (20) can exchange heat with the fluid discharged through the exhaust port (11).

2. The chiller system according to claim 1, characterized in that: The outlet portion of the heat exchanger (20) comprises a first outlet (21) and a second outlet (22) which are arranged at an interval, the second outlet (22) being located below the first outlet (21), the first outlet (21) being in communication with the compressor (10), and the second outlet (22) forming at least a part of the outlet portion of the heat exchanger (20); and / or, The chiller system further comprises a first valve body (40), the first valve body (40) being arranged at least in part of the outlet of the heat exchanger (20), the first valve body (40) being used to control the connection or disconnection between at least in part of the outlet of the heat exchanger (20) and the inlet (33); and / or, The chiller system further comprises a pump body (50), wherein the pump body (50) is disposed at least partially at the outlet of the heat exchanger (20), and the pump body (50) is used to allow at least part of the fluid flowing out through the outlet of the heat exchanger (20) to pass into the inlet (33).

3. The chiller system according to claim 1, characterized in that: The inlet (33) is connected to the exhaust port (11) via an exhaust pipe (150); the chiller system further comprises: a pressure detection member (60) disposed at the exhaust pipe (150); and / or a temperature detection element (70) disposed at the exhaust duct (150); and / or, A liquid level detection component is arranged in the heat exchanger (20), and the liquid level detection component is used to detect the refrigerant liquid level in the heat exchanger (20).

4. The chiller system according to claim 1, characterized in that: The gas-liquid separator (30) further comprises a second separation port (32), wherein the second separation port (32) is located below the first separation port (31) and is used to communicate with the compressor (10); the chiller system further comprises: an oil filter (120), disposed at the second separation port (32), the oil filter (120) being used to filter impurities in the fluid discharged from the second separation port (32); and / or, A second valve body (80) is arranged at the second separation port (32), and the second valve body (80) is used to control the connection or disconnection between the second separation port (32) and the compressor (10).

5. The chiller system according to claim 1, characterized in that: The chiller system also includes: an ejector (90) for communicating with the air intake port (12) of the compressor (10); the inlet port of the ejector (90) can be selectively connected to or disconnected from the second outlet (22) of the heat exchanger (20), and the ejection port of the ejector (90) can be selectively connected to or disconnected from the air exhaust port (11); The ejector (90) has an ejection state in which the inlet of the ejector (90) is connected to the second outlet (22), the ejection port of the ejector (90) is connected to the exhaust port (11), and the ejector (90) is connected to the air intake port (12); and a closed state in which the inlet of the ejector (90) is disconnected from the second outlet (22), and the ejection port of the ejector (90) is disconnected from the exhaust port (11).

6. An oil return control method, characterized in that: Applicable to the chiller system according to any one of claims 1 to 5, the oil return control method comprises: Obtaining at least one of the amount of refrigerant in the heat exchanger of the chiller system and the exhaust temperature of the compressor of the chiller system; According to at least one of the refrigerant quantity and the exhaust gas temperature, the connection or disconnection between at least a part of the outlet of the heat exchanger and the inlet of the gas-liquid separator of the chiller system is controlled.

7. The oil return control method according to claim 6, characterized in that: The exhaust gas temperature condition includes the exhaust gas temperature of the compressor; and / or, The exhaust gas temperature condition includes the exhaust gas superheat of the compressor; and / or, The refrigerant quantity condition includes the refrigerant liquid level in the heat exchanger.

8. The oil return control method according to claim 6, characterized in that: The controlling the connection or disconnection between at least a portion of the outlet of the heat exchanger and the inlet of the gas-liquid separator of the chiller system according to at least one of the refrigerant quantity and the exhaust gas temperature comprises: Obtaining the refrigerant liquid level in the heat exchanger, the exhaust temperature of the compressor, and the operating time of the compressor; Determine whether the chiller system satisfies a first preset judgment condition, a second preset judgment condition, a third preset judgment condition and a fourth preset judgment condition at the same time; When the chiller system satisfies the first preset judgment condition, the second preset judgment condition, the third preset judgment condition and the fourth preset judgment condition at the same time, controlling at least a portion of the outlet of the heat exchanger to be connected to the inlet; Among them, the first preset judgment condition is that the exhaust temperature of the compressor is greater than the preset temperature value; the second preset judgment condition is that the exhaust superheat of the compressor is greater than the preset superheat; the third preset judgment condition is that the refrigerant liquid level in the heat exchanger is greater than the first preset liquid level value; the fourth preset judgment condition is that the operating time of the compressor is greater than the preset time value.

9. The oil return control method according to claim 8, characterized in that: The determining whether the chiller system satisfies a first preset determination condition comprises: obtaining the exhaust temperature of the compressor within a first preset temperature measurement time range; determining whether the exhaust temperature of the compressor within the first preset temperature measurement time range is greater than the preset temperature value; when the exhaust temperature of the compressor within the first preset temperature measurement time range is greater than the preset temperature value, determining that the chiller system satisfies the first preset determination condition; and / or, The determining whether the chiller system satisfies a second preset determination condition comprises: obtaining the exhaust superheat of the compressor within a second preset temperature measurement time range; determining whether the exhaust superheat of the compressor within the second preset temperature measurement time range is greater than the preset superheat; when the exhaust superheat of the compressor within the second preset temperature measurement time range is greater than the preset superheat, determining that the chiller system satisfies the second preset determination condition; and / or, The ratio of the first preset liquid level value to the height of the storage chamber of the heat exchanger for storing the refrigerant is greater than 0 and less than or equal to 0.

3.

10. The oil return control method according to claim 8, characterized in that: The preset temperature value is greater than or equal to 60° C. and less than or equal to 100° C.; and / or, The preset superheat is greater than 0°C and less than or equal to 30°C; and / or, The preset duration value is greater than or equal to 30 minutes.

11. The oil return control method according to claim 6, characterized in that: The oil return control method further includes: Obtaining at least one of the refrigerant liquid level in the heat exchanger, the exhaust temperature of the compressor, and the operating state of the compressor; Determine whether the chiller system satisfies at least one of a fifth preset judgment condition, a sixth preset judgment condition, and a seventh preset judgment condition; When the chiller system satisfies at least one of the fifth preset judgment condition, the sixth preset judgment condition, and the seventh preset judgment condition, controlling at least a portion of the outlet of the heat exchanger to be disconnected from the inlet; Among them, the fifth preset judgment condition is that the exhaust superheat of the compressor is less than or equal to the preset superheat; the sixth preset judgment condition is that the refrigerant liquid level in the heat exchanger is less than the second preset liquid level value; and the seventh preset judgment condition is that the compressor is in a closed state.

12. The oil return control method according to claim 11, characterized in that: The determining whether the chiller system satisfies the fifth preset determination condition comprises: obtaining the exhaust superheat of the compressor within the third preset temperature measurement time range; determining whether the exhaust superheat of the compressor within the third preset temperature measurement time range is less than or equal to the preset superheat; when the exhaust superheat of the compressor within the third preset temperature measurement time range is less than or equal to the preset superheat, determining that the chiller system satisfies the fifth preset determination condition; and / or, The ratio of the second preset liquid level value to the height of the storage chamber of the heat exchanger for storing the refrigerant is greater than 0 and less than or equal to 0.3.

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