Cooling system and heat pump unit

Abstract

The application relates to a cooling system, which comprises an evaporator, a compressor motor, a motor cooling circuit, a cooling assembly and a cooling compressor. The motor cooling circuit comprises a first cooling pipeline and a second cooling pipeline which are communicated with the evaporator and the compressor motor. The first cooling pipeline is used to extract refrigerant of the evaporator and deliver the refrigerant to the compressor motor of the heat pump unit. The second cooling pipeline is used to deliver the heat-exchanged refrigerant back to the evaporator. The cooling assembly is arranged in the first cooling pipeline and used to cool the refrigerant in the first cooling pipeline. The cooling compressor is arranged in the second cooling pipeline. The low-temperature liquid refrigerant extracted from the evaporator is secondarily cooled through the arrangement of the cooling assembly, so that the heat exchange temperature difference is enlarged, the heat exchange efficiency is improved, and the refrigerant is pressurized through the arrangement of the cooling compressor, so that the heat-exchanged refrigerant can smoothly flow back to the evaporator.

Description

Technical Field

[0001] This application relates to the field of heat pump cooling technology, and in particular to a cooling system and a heat pump unit. Background Technology

[0002] High-temperature heat pump systems, as highly efficient energy conversion devices, are widely used in various fields such as industrial heating, building heating, and domestic hot water supply. Their core function is to transfer and enhance heat by driving a refrigerant cycle through a compressor, offering significant advantages such as low energy consumption and good environmental performance. Among the core components of high-temperature heat pump units, the operating status of the compressor motor directly affects the overall performance and reliability of the unit. During high-speed operation, the motor continuously generates a large amount of heat. If it cannot be effectively cooled in time, it will lead to excessively high motor temperatures, causing problems such as insulation aging and decreased operating efficiency. Therefore, the cooling system of the compressor motor is a crucial aspect of the design of high-temperature heat pump systems.

[0003] Currently, the cooling system of the compressor motor in high-temperature heat pump units typically employs direct refrigerant cooling, which involves drawing a portion of the refrigerant from the main circulation loop to cool the motor. One method involves drawing a portion of low-temperature liquid refrigerant from the condenser and guiding it through pipelines to the cooling channels of the compressor motor. As the refrigerant flows through the motor, it absorbs the heat generated by the motor, causing its own temperature to rise or undergo a phase change. It then flows back into the evaporator through the return pipeline, thus carrying away the heat. However, for the refrigerant to flow smoothly into the evaporator, its temperature usually needs to be higher than that of the evaporator. This results in an excessively high initial refrigerant temperature. When this high-temperature refrigerant flows through the compressor motor, the temperature difference between the refrigerant and the motor decreases, significantly reducing heat exchange efficiency. This makes it unable to effectively absorb the heat generated by the motor, leading to a significant decrease in cooling performance or even failure. Summary of the Invention

[0004] In order to solve the problem that the cooling system in a high-temperature heat pump unit has insufficient cooling capacity for the motor due to the excessively high temperature of the refrigerant itself, this application provides a cooling system and a heat pump unit.

[0005] Firstly, the cooling system provided in this application adopts the following technical solution:

[0006] A cooling system for a heat pump unit, the cooling system comprising:

[0007] Evaporator and compressor motor;

[0008] The motor cooling circuit includes a first cooling pipe and a second cooling pipe connecting the evaporator and the compressor motor. The first cooling pipe is used to draw refrigerant from the evaporator and deliver it to the compressor motor of the heat pump unit. The second cooling pipe is used to return the refrigerant after heat exchange to the evaporator.

[0009] A cooling assembly, disposed in the first cooling pipe, is used to cool the refrigerant within the first cooling pipe; and...

[0010] A cooling compressor, located in the second cooling line, is used to pressurize the refrigerant in the second cooling line so that the refrigerant can flow back to the evaporator.

[0011] By adopting the above technical solution, the low-temperature liquid refrigerant extracted from the evaporator is cooled twice by the cooling components, enabling it to exchange heat with the compressor motor at a lower temperature. This significantly improves heat exchange efficiency, fully absorbs the heat generated by the compressor motor, effectively controls the compressor motor temperature, and prevents problems such as insulation aging and decreased operating efficiency caused by overheating. Furthermore, by setting up a cooling compressor to pressurize the refrigerant after heat exchange, it is ensured that the refrigerant can flow smoothly back to the evaporator to form a stable cooling cycle. This eliminates the need to rely on the refrigerant's own pressure difference, thus ensuring the continuous and stable operation of the cooling system. In turn, this helps to improve the overall reliability and operating efficiency of the high-temperature heat pump unit.

[0012] Optionally, the first cooling pipeline is further provided with a mixer and a cooling pump. The mixer and the cooling pump are located between the cooling component and the compressor motor, and are arranged sequentially along the fluid flow direction. The mixer is connected to the evaporator through a return gas pipeline, and the cooling compressor is located on the return gas pipeline.

[0013] The second cooling pipeline includes the return gas pipeline.

[0014] By adopting the above technical solution, a cooling pump is installed to provide power for the refrigerant in the first cooling pipe, so that the refrigerant flows stably in the first cooling pipe, ensuring that all parts of the motor are adequately cooled and that local overheating is not caused by insufficient flow rate. Furthermore, by installing a mixer, the gas and liquid phases of the refrigerant can be separated to reduce the proportion of gas phase in the refrigerant, so that the cooling pump can input more liquid refrigerant into the compressor motor.

[0015] Optionally, the second cooling pipeline further includes a return pipeline, which connects the compressor motor and the mixer to input the heat-exchanged refrigerant into the mixer for mixing.

[0016] By adopting the above technical solution and setting up a return pipeline to re-input the refrigerant after heat exchange into the mixer, the fluid fluctuations in the motor cooling circuit can be balanced on the one hand, and the refrigerant after heat exchange can be processed by the mixer to achieve gas-liquid separation, thus avoiding the need to set up an additional gas-liquid separator, thereby helping to reduce the cost of the cooling system.

[0017] Optionally, the cooling system further includes:

[0018] An oil-gas separator is provided in the return gas line and is located between the compressor and the evaporator; and,

[0019] An oil-gas return line connects the oil-gas separator to the cooling compressor, and is used to inject the separated lubricating oil into the cooling compressor.

[0020] By adopting the above technical solution, an oil-gas separator is installed to prevent lubricating oil from entering the evaporator, thus avoiding a decrease in heat exchange efficiency due to oil accumulation on the surface of the evaporator heat exchange tubes. This ensures that the main circulation of the heat pump unit can operate stably and efficiently. Furthermore, by setting up an oil-gas return pipeline, the separated lubricating oil is recovered and reinjected into the cooling compressor, allowing the lubricating oil to be recycled. This not only helps reduce lubricating oil consumption but also ensures good lubrication of the internal components of the cooling compressor, reducing frictional losses and thus helping to extend the service life of the cooling compressor.

[0021] Optionally, the cooling system further includes an oil cooling circuit, wherein an oil tank, an oil pump, a heat exchanger and a heat pump compressor are arranged sequentially along the flow direction in the oil cooling circuit;

[0022] The lubricating oil in the oil tank is pressurized by the oil pump, cooled by the heat exchanger, and then enters the heat pump compressor. The lubricating oil lubricates the bearings and carries away the heat from the bearings before leaving the heat pump compressor and re-entering the oil tank.

[0023] By adopting the above technical solution, the compressor bearing is lubricated and cooled by an independently set oil cooling circuit, avoiding problems such as accelerated wear and increased operating resistance caused by overheating of the compressor bearing. This can significantly improve the service life and operational stability of the compressor bearing. At the same time, by setting up a heat exchanger to cool the lubricating oil, the lubricating oil can continuously and efficiently absorb the bearing heat, effectively control the bearing temperature, and ensure that the heat pump compressor is always in good operating condition.

[0024] Optionally, the cooling system includes a return pipe and a heat exchange pipe, the heat exchange pipe connecting the first cooling pipe and the return pipe, and the heat exchanger being disposed in the heat exchange pipe; and / or,

[0025] The cooling system also includes an exhaust pipe that connects the oil tank to the evaporator.

[0026] By adopting the above technical solution, heat exchange pipelines are set up to introduce refrigerant into the heat exchanger so that the refrigerant can be used to cool the lubricating oil in the oil cooling circuit, thus avoiding the introduction of other cooling fluids and helping to simplify the structure of the cooling system. By setting up exhaust pipelines to connect the oil tank to the evaporator, the refrigerant in the oil cooling circuit can be introduced into the evaporator. This can maintain the pressure balance in the oil tank, prevent the pressure in the oil tank from being too high or too low and affecting the operation of the oil pump, and recover any refrigerant that may escape, thus reducing refrigerant loss.

[0027] Optionally, the cooling system further includes a gas supply line and a gas supply valve. One end of the gas supply line is connected to the exhaust line, and the other end is connected to the air inlet of the cooling compressor. The gas supply valve is located in the gas supply line.

[0028] By adopting the above technical solution, a gas replenishment pipeline is set up to connect the exhaust pipeline and the return pipeline. A gas replenishment valve is set up to control the opening and closing of the gas replenishment pipeline. When gaseous refrigerant in the gas replenishment pipeline needs to be input into the cooling compressor, the gaseous refrigerant resources in the exhaust pipeline can be recovered and utilized. At the same time, the intake volume of the cooling compressor can be adjusted according to the actual needs of the cooling compressor to avoid insufficient intake problems. This ensures that the cooling compressor can operate efficiently and stably under various operating conditions.

[0029] Optionally, the oil cooling circuit includes an oil cooling return line connecting the compressor and the oil tank, and the oil cooling return line is equipped with a return valve;

[0030] The cooling system also includes an oil replenishment line and an oil replenishment valve. The oil replenishment line connects the oil-cooled return line to the cooling compressor, and the oil replenishment valve is located on the oil replenishment line.

[0031] By adopting the above technical solution, the oil-cooled return oil pipeline and the return oil valve work together to ensure that the lubricating oil can flow back to the oil tank stably, maintain the normal level of lubricating oil in the oil tank, and ensure the continuous circulation of the oil-cooling circuit. This prevents the compressor bearings from experiencing increased wear due to insufficient lubrication. At the same time, by setting up the oil replenishment pipeline and the oil replenishment valve, on the one hand, the lubricating oil can be flexibly adjusted according to the actual needs of cooling the compressor, ensuring that it is always in a good lubrication state. On the other hand, replenishing the lubricating oil from the oil-cooling circuit allows the lubricating oil to be rationally distributed and efficiently utilized, which helps to reduce the consumption of lubricating oil, thereby reducing the maintenance cost and failure risk of the cooling system.

[0032] Optionally, the cooling assembly includes an electronic expansion valve and / or an orifice plate disposed in the first cooling pipeline.

[0033] By adopting the above technical solution, and by setting an electronic expansion valve or orifice plate to throttle and cool the refrigerant drawn from the evaporator, the refrigerant entering the compressor motor is kept at an extremely low temperature, so as to increase the temperature difference between the refrigerant and the compressor motor, thereby greatly improving the heat exchange efficiency.

[0034] Secondly, the heat pump unit provided in this application adopts the following technical solution:

[0035] A heat pump unit includes a cooling system, the cooling system comprising:

[0036] Evaporator and compressor motor;

[0037] The motor cooling circuit includes a first cooling pipe and a second cooling pipe connecting the evaporator and the compressor motor. The first cooling pipe is used to draw refrigerant from the evaporator and deliver it to the compressor motor of the heat pump unit. The second cooling pipe is used to return the refrigerant after heat exchange to the evaporator.

[0038] A cooling assembly, disposed in the first cooling pipe, is used to cool the refrigerant within the first cooling pipe; and...

[0039] A cooling compressor, located in the second cooling line, is used to pressurize the refrigerant in the second cooling line so that the refrigerant can flow back to the evaporator.

[0040] In summary, this application includes at least one of the following beneficial technical effects:

[0041] 1. The refrigerant drawn from the evaporator is cooled a second time by the cooling components, which significantly reduces the temperature of the refrigerant, thereby increasing the temperature difference with the compressor motor, improving heat exchange efficiency, effectively absorbing the heat generated by the motor, and avoiding insulation aging and efficiency reduction caused by motor overheating. At the same time, the cooling compressor pressurizes the returning refrigerant to ensure that the refrigerant returns to the evaporator stably, forming a closed loop. This can effectively enhance the reliability and overall energy efficiency of the system under high heat load conditions.

[0042] 2. The independent oil cooling circuit enables dedicated lubrication and cooling of the heat pump compressor bearings. Through the coordinated work of the oil pump and heat exchanger, the lubricating oil is kept at a low temperature, which efficiently removes heat from the bearings, prevents overheating and wear, improves the operating stability and service life of the compressor, and optimizes thermal management in conjunction with other cooling components to reduce the risk of failure.

[0043] 3. Through the design of oil-gas separator and oil return pipeline, lubricating oil is effectively separated and recovered, preventing oil sludge from accumulating in the evaporator and affecting heat exchange efficiency. At the same time, the gas supply pipeline and oil supply pipeline realize the resource reuse of refrigerant and lubricating oil, regulate system pressure and flow, reduce maintenance costs and energy consumption, and further ensure the long-term stable operation of the cooling system. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the cooling system provided in this application;

[0045] Figure 2 yes Figure 1 A schematic diagram of the motor cooling circuit in the cooling system;

[0046] Figure 3 yes Figure 1 A schematic diagram of the oil cooling circuit of the cooling system.

[0047] Explanation of reference numerals in the attached figures:

[0048] 100. Cooling system; 1. Evaporator; 2. Heat pump compressor; 21. Compressor motor; 22. Compressor bearing; 3. Motor cooling circuit; 31. First cooling pipe; 311. First liquid inlet pipe; 312. Second liquid inlet pipe; 32. Second cooling pipe; 321. Gas return pipe; 322. Return pipe; 33. Mixer; 34. Cooling pump; 4. Cooling components; 41. Electronic expansion valve; 42. Orifice plate; 5. Cooling compressor; 61. Oil-gas separator; 62. Oil-gas return pipe; 7. Oil cooling circuit; 71. Oil cooling return pipe; 72. Oil tank; 721. Exhaust pipe; 73. Oil pump; 74. Heat exchanger; 75. Heat exchange pipe; 76. Oil return valve; 8. Gas replenishment valve; 91. Oil replenishment pipe; 92. Oil replenishment valve. Detailed Implementation

[0049] The following is in conjunction with the appendix Figure 1 To be continued Figure 3 This application will be described in further detail below.

[0050] In one embodiment of this application, please refer to Figure 1 and Figure 2 The cooling system 100 includes an evaporator 1, a compressor motor 21, a motor cooling circuit 3, a cooling assembly 4, and a cooling compressor 5. The motor cooling circuit 3 includes a first cooling pipe 31 and a second cooling pipe 32 connecting the evaporator 1 and the compressor motor 21. The first cooling pipe 31 is used to draw refrigerant from the evaporator 1 and deliver it to the compressor motor 21 of the heat pump unit. The second cooling pipe 32 is used to return the refrigerant after heat exchange to the evaporator 1. The cooling assembly 4 is located in the first cooling pipe 31 and is used to cool the refrigerant in the first cooling pipe 31. The cooling compressor 5 is located in the second cooling pipe 32 and is used to pressurize the refrigerant in the second cooling pipe 32 so that the refrigerant can flow back to the evaporator 1.

[0051] It should be noted that liquid refrigerant is delivered to the compressor motor 21 for cooling via the first cooling pipe 31, and then returned to the evaporator 1 via the second cooling pipe 32. Compared to refrigerant drawn from the condenser, the refrigerant drawn from the evaporator 1 has a lower temperature and pressure, ensuring that the drawn liquid refrigerant has a lower initial temperature. A cooling component 4 is provided on the first cooling pipe 31 to pre-cool the refrigerant before it enters the compressor motor 21, further reducing the refrigerant temperature so that it can be lowered below the evaporator 1, thereby improving its heat absorption capacity. At the same time, a cooling compressor 5 is provided on the second cooling pipe 32 to pressurize the refrigerant after heat exchange, enabling it to overcome the system pressure difference and flow smoothly back to the evaporator 1.

[0052] In the technical solution of this application, the low-temperature liquid refrigerant extracted from the evaporator 1 is cooled twice by the cooling component 4, and can then exchange heat with the compressor motor 21 at a lower temperature. This helps to significantly improve the heat exchange efficiency, fully absorb the heat generated by the operation of the compressor motor 21, effectively control the temperature of the compressor motor 21, and avoid problems such as insulation aging and reduced operating efficiency caused by overheating of the compressor motor 21. Furthermore, by setting up a cooling compressor 5, the refrigerant after heat exchange is pressurized to ensure that the refrigerant can flow back to the evaporator 1 smoothly to form a stable cooling cycle. This does not require reliance on the pressure difference of the refrigerant itself, thereby ensuring the continuous and stable operation of the cooling system 100, and thus helping to improve the overall reliability and working efficiency of the high-temperature heat pump unit.

[0053] In one embodiment of this application, a mixer 33 and a cooling pump 34 are also provided on the first cooling pipe 31. The mixer 33 and the cooling pump 34 are located between the cooling assembly 4 and the compressor motor 21 and are arranged sequentially along the fluid flow direction. The mixer 33 is connected to the evaporator 1 through the return gas pipe 321. The cooling compressor 5 is located in the return gas pipe 321. The second cooling pipe 32 includes the return gas pipe 321. In this way, by setting the cooling pump 34, power is provided to the refrigerant in the first cooling pipe 31, so that the refrigerant flows stably in the first cooling pipe 31, ensuring that all parts of the motor are sufficiently cooled and that local overheating does not occur due to insufficient flow rate. By setting the mixer 33, the gas and liquid phases of the refrigerant can be separated to reduce the proportion of the gas phase in the refrigerant, so that the cooling pump 34 can input more liquid refrigerant into the compressor motor 21.

[0054] Understandably, the refrigerant cooled by the cooling assembly 4 first enters the mixer 33, which mixes the refrigerant evenly, ensuring a stable temperature of the refrigerant entering the compressor motor 21. Subsequently, the cooling pump 34 provides additional power for the delivery of liquid refrigerant, ensuring that the liquid refrigerant flows through the motor cooling channel at a sufficient flow rate, improving the heat exchange effect. The return gas pipeline 321, as part of the second cooling pipeline 32, works in conjunction with the cooling compressor 5 to allow the gaseous refrigerant to flow back to the evaporator 1. Further, the first cooling pipeline 31 includes a first liquid inlet pipeline 311 and a second liquid inlet pipeline 312. The first liquid inlet pipeline 311 connects the evaporator 1 and the mixer 33 to draw liquid refrigerant and deliver it to the mixer 33. The cooling assembly 4 is mounted on the first liquid inlet pipeline 311, and the second liquid inlet pipeline 312 connects the mixer 33 and the compressor motor 21 to input the liquid refrigerant into the cooling pipeline of the compressor motor 21 for cooling.

[0055] To avoid drawing too much or too little refrigerant, in one embodiment of this application, the mixer 33 is equipped with a first level gauge, which enables the system to accurately control the amount of refrigerant drawn from the evaporator 1. This prevents excessive refrigerant drawing from the evaporator 1 from causing a drop in the liquid level of the evaporator 1 and affecting the main circulation, or insufficient refrigerant drawing from the mixer 33 from causing insufficient refrigerant in the mixer 33 and affecting the cooling effect of the compressor motor 21. This allows the motor cooling circuit 3 to dynamically adjust the refrigerant supply according to actual needs, ensuring the cooling effect while minimizing interference with the operation of the heat pump unit.

[0056] In one embodiment of this application, the second cooling pipe 32 further includes a return pipe 322, which connects the compressor motor 21 and the mixer 33. The return pipe 322 is used to input the refrigerant after heat exchange into the mixer 33 for mixing. After the refrigerant flows through the compressor motor 21 and completes heat exchange, its temperature rises. It is then directly introduced into the mixer 33 through the return pipe 322 to fully mix with the low-temperature refrigerant delivered from the cooling assembly 4 to the mixer 33. The cooling capacity of the low-temperature refrigerant is used to reduce the temperature of the refrigerant after heat exchange. The refrigerant is then delivered to the compressor motor 21 for circulating cooling via the cooling pump 34. Thus, by setting up the return pipe 322 to re-input the refrigerant after heat exchange into the mixer 33, the fluid fluctuations in the motor cooling circuit 3 are balanced. On the other hand, the refrigerant after heat exchange can be processed by the mixer 33, enabling gas-liquid separation of the refrigerant. This eliminates the need for an additional gas-liquid separator, thereby helping to reduce the cost of the cooling system 100. Of course, in other embodiments, the refrigerant after heat exchange can also be separated by a gas-liquid separator and other pipelines and directly input into the cooling compressor 5, etc. The embodiments of this application do not limit this.

[0057] In one embodiment of this application, the cooling system 100 further includes an oil-gas separator 61 and an oil-gas return line 62. The oil-gas separator 61 is located in the return line 321 and between the compressor and the evaporator 1. The oil-gas return line 62 connects the oil-gas separator 61 and the cooling compressor 5 to inject the separated lubricating oil into the cooling compressor 5.

[0058] Since the refrigerant may carry the lubricating oil in the cooling compressor 5 during the circulation process, when the refrigerant flows through the oil-gas separator 61, the oil-gas separator 61 can separate the lubricating oil in the refrigerant from the gaseous refrigerant, so as to prevent the lubricating oil from entering the evaporator 1 with the refrigerant and affecting the heat exchange efficiency of the main cycle of the heat pump unit. At the same time, the separated lubricating oil flows back to the cooling compressor 5 through the oil-gas return pipeline 62, providing continuous lubrication for the operation of the cooling compressor 5 and reducing component wear.

[0059] In this embodiment, an oil-gas separator 61 is provided to prevent lubricating oil from entering the evaporator 1, thus avoiding a decrease in heat exchange efficiency due to oil accumulation on the surface of the heat exchange tubes of the evaporator 1. This ensures that the main circulation of the heat pump unit can operate stably and efficiently. Furthermore, by providing an oil-gas return pipeline 62, the separated lubricating oil is recovered and reinjected into the cooling compressor 5, allowing the lubricating oil to be recycled. This not only helps reduce the consumption of lubricating oil but also ensures good lubrication of the internal components of the cooling compressor 5, reducing frictional losses and thus helping to extend the service life of the cooling compressor 5.

[0060] In one embodiment of this application, please refer to Figure 1 and Figure 3 The cooling system 100 also includes an oil cooling circuit 7. The oil cooling circuit 7 is arranged in sequence along the flow direction, including an oil tank 72, an oil pump 73, a heat exchanger 74, and a heat pump compressor 2. The lubricating oil in the oil tank 72 is pressurized by the oil pump 73, cooled by the heat exchanger 74, and then enters the heat pump compressor 2. The lubricating oil lubricates the bearing and carries away the heat from the bearing before leaving the heat pump compressor 2 and re-entering the oil tank 72. In this way, the independently set oil cooling circuit 7 lubricates and cools the compressor bearing 22, avoiding problems such as increased wear and increased operating resistance caused by overheating of the compressor bearing 22. This can significantly improve the service life and operational stability of the compressor bearing 22. At the same time, by setting up the heat exchanger 74 to cool the lubricating oil, the lubricating oil can continuously and efficiently absorb the bearing heat, effectively control the bearing temperature, and ensure that the heat pump compressor 2 is always in good operating condition.

[0061] In one embodiment of this application, the cooling system 100 includes a return pipe 322 and a heat exchange pipe 75. The heat exchange pipe 75 connects the first cooling pipe 31 and the return pipe 322. A heat exchanger 74 is disposed in the heat exchange pipe 75. Thus, by providing the heat exchange pipe 75, refrigerant is introduced into the heat exchanger 74 to cool the lubricating oil in the oil cooling circuit 7, preventing the introduction of other cooling fluids and thus simplifying the structure of the cooling system 100. Of course, in other embodiments, the heat exchanger 74 may also use cooling water for cooling, etc., and this embodiment of the application does not limit this. Furthermore, the inlet of the return pipe 322 is located between the cooling pump 34 and the compressor motor 21, so that the cooling pump 34 can drive the refrigerant to flow stably in the heat exchange pipe.

[0062] In one embodiment of this application, the cooling system 100 further includes an exhaust pipe 721, which connects the oil tank 72 and the evaporator 1. Since the lubricating oil carries some refrigerant during the circulating cooling process, in this embodiment, by setting the exhaust pipe 721 to connect the oil tank 72 to the evaporator 1, the refrigerant in the oil cooling circuit 7 is introduced into the evaporator 1. This can maintain the pressure balance in the oil tank 72, prevent the pressure in the oil tank 72 from being too high or too low and affecting the operation of the oil pump 73, and also recover any refrigerant that may escape, thus reducing refrigerant loss.

[0063] In one embodiment of this application, the cooling system 100 further includes a gas supply line and a gas supply valve 8. One end of the gas supply line is connected to the exhaust line 721, and the other end is connected to the air inlet of the cooling compressor 5. The gas supply valve 8 is located in the gas supply line. If the inlet pressure of the cooling compressor 5 is too low during operation, it will affect its compression efficiency and refrigerant delivery capacity. Since the gas discharged from the exhaust pipe 721 contains gaseous refrigerant, this gaseous refrigerant can be introduced into the inlet of the cooling compressor 5 through the make-up gas pipe. The make-up gas valve 8 controls the opening and closing of the make-up gas pipe. In this way, by setting up the make-up gas pipe to connect the exhaust pipe 721 and the return gas pipe 321, and by setting up the make-up gas valve 8 to control the opening and closing of the make-up gas pipe, the gaseous refrigerant in the make-up gas pipe can be input into the cooling compressor 5 when needed. This not only recovers and utilizes the gaseous refrigerant resources in the exhaust pipe 721, but also adjusts the intake volume of the cooling compressor 5 according to its actual needs, so as to avoid the problem of insufficient intake of the cooling compressor 5, thereby ensuring that the cooling compressor 5 can operate efficiently and stably under various operating conditions.

[0064] In one embodiment of this application, the oil cooling circuit 7 includes an oil cooling return line 71 connecting the compressor and the oil tank 72. An oil return valve 76 is provided on the oil cooling return line 71. The cooling system 100 also includes a replenishment line 91 and a replenishment valve 92. The replenishment line 91 connects the oil cooling return line 71 to the cooling compressor 5. The replenishment valve 92 is located on the replenishment line 91. Normally, the return valve 76 is open and the replenishment valve 92 is closed, allowing lubricating oil to circulate in the oil cooling circuit 7 to lubricate and cool the compressor bearing 22. When the oil level in the oil tank 72 is too high or the cooling compressor 5 is insufficiently lubricated, the return valve 76 closes and the replenishment valve 92 opens to introduce lubricating oil into the cooling compressor. In this configuration, the oil-cooled return oil line 71 and the return oil valve 76 work together to ensure that the lubricating oil can flow back stably to the oil tank 72, maintain the normal level of lubricating oil in the oil tank 72, and ensure the continuous circulation of the oil-cooling circuit 7. This prevents the compressor bearing 22 from experiencing increased wear due to insufficient lubrication. At the same time, by setting up the oil replenishment line 91 and the oil replenishment valve 92, on the one hand, the lubricating oil can be flexibly adjusted according to the actual needs of cooling the compressor 5 to ensure that it is always in a good lubrication state. On the other hand, replenishing the lubricating oil from the oil-cooling circuit 7 allows the lubricating oil to be rationally distributed and efficiently utilized, which helps to reduce the consumption of lubricating oil, thereby reducing the maintenance cost and failure risk of the cooling system 100.

[0065] In one embodiment of this application, the oil tank 72 is equipped with a second level gauge to monitor the lubricating oil level in the oil tank 72 in real time, promptly detect and handle abnormal levels, avoid problems such as poor lubrication and accelerated wear of the heat pump compressor 2 and cooling compressor 5 due to insufficient lubricating oil, and prevent lubricating oil waste and overflow risks caused by excessively high levels. Thus, by accurately monitoring the level, precise control of lubricating oil replenishment and return can be achieved, maintaining the optimal level of lubricating oil in the oil tank 72, ensuring the stable operation of the oil cooling circuit 7 and cooling compressor 5, reducing the maintenance cost and failure rate of the cooling system 100, thereby helping to improve the reliability and maintainability of the cooling system 100.

[0066] In one embodiment of this application, the cooling assembly 4 includes an electronic expansion valve 41 and / or an orifice plate 42 disposed in the first cooling pipe 31 to reduce the pressure and temperature of the refrigerant through a throttling effect. When the refrigerant from the evaporator 1 passes through the electronic expansion valve 41 or the orifice plate 42, its pressure drops rapidly, accompanied by flash evaporation of some of the refrigerant, resulting in a further reduction in the temperature of the refrigerant, even reaching saturation. After the low-temperature, low-pressure refrigerant enters the cooling channel of the compressor motor 21, it can more efficiently absorb the heat generated by the motor, achieving enhanced cooling of the compressor motor 21. The electronic expansion valve 41 has the function of precisely regulating the flow rate, and can adjust the degree of throttling and the flow rate of the refrigerant in real time according to the temperature requirements of the compressor motor 21 and the state of the refrigerant, so that the refrigerant is cooled to a suitable temperature. The orifice plate 42 achieves throttling, pressure reduction, and temperature reduction of the refrigerant through its own structure. The structure is simple and highly reliable. The two can be used alone or in combination to target the refrigerant in the first cooling pipe 31 and further reduce the temperature of the refrigerant.

[0067] In this embodiment, by setting an electronic expansion valve 41 or an orifice plate 42, the refrigerant drawn from the evaporator 1 is throttled and cooled to ensure that the refrigerant entering the compressor motor 21 is at an extremely low temperature, so as to increase the temperature difference between the refrigerant and the compressor motor 21, thereby greatly improving the heat exchange efficiency.

[0068] This application also provides a heat pump unit, which includes a cooling system 100. It should be noted that the specific structure of the cooling system 100 is the same as described in the above embodiments. Since this heat pump unit adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0069] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be included within the scope of protection of this application.

Claims

1. A cooling system for a heat pump unit, characterized in that, The cooling system includes: Evaporator (1) and compressor motor (21); The motor cooling circuit (3) includes a first cooling pipe (31) and a second cooling pipe (32) connecting the evaporator (1) and the compressor motor (21). The first cooling pipe (31) is used to draw refrigerant from the evaporator (1) and deliver it to the compressor motor (21) of the heat pump unit. The second cooling pipe (32) is used to return the refrigerant after heat exchange to the evaporator (1). A cooling assembly (4) is disposed in the first cooling pipe (31) for cooling the refrigerant in the first cooling pipe (31); and, A cooling compressor (5) is provided in the second cooling pipe (32) to pressurize the refrigerant in the second cooling pipe (32) so that the refrigerant can flow back to the evaporator (1); The first cooling pipe (31) is also provided with a mixer (33) and a cooling pump (34). The mixer (33) and the cooling pump (34) are located between the cooling component (4) and the compressor motor (21) and are arranged sequentially along the fluid flow direction. The mixer (33) is connected to the evaporator (1) through the return gas pipe (321). The cooling compressor (5) is located on the return gas pipe (321). The second cooling pipe (32) includes the return air pipe (321); The second cooling pipe (32) also includes a return pipe (322), which connects the compressor motor (21) and the mixer (33) to input the heat-exchanged refrigerant into the mixer (33) for mixing; The cooling system also includes an oil cooling circuit (7), which is provided with an oil tank (72), an oil pump (73), a heat exchanger (74) and a heat pump compressor (2) in sequence along the flow direction; Among them, the lubricating oil in the oil tank (72) is pressurized by the oil pump (73), cooled by the heat exchanger (74), and then enters the heat pump compressor (2). The lubricating oil lubricates the bearing and carries away the heat of the bearing before leaving the heat pump compressor (2) and re-entering the oil tank (72). The cooling system includes a return pipe (322) and a heat exchange pipe (75), the heat exchange pipe (75) connecting the first cooling pipe (31) and the return pipe (322), and the heat exchanger (74) is located in the heat exchange pipe (75); The oil cooling circuit (7) includes an oil cooling return line (71) connecting the compressor and the oil tank (72), and an oil return valve (76) is provided on the oil cooling return line (71).

2. The cooling system according to claim 1, characterized in that, The cooling system also includes: An oil-gas separator (61) is provided in the return gas line (321) and is located between the compressor and the evaporator (1); and, An oil-gas return line (62) connects the oil-gas separator (61) and the cooling compressor (5) to inject the separated lubricating oil into the cooling compressor (5).

3. The cooling system according to claim 1, characterized in that, The cooling system also includes an exhaust pipe (721) that connects the oil tank (72) to the evaporator (1).

4. The cooling system according to claim 3, characterized in that, The cooling system also includes a gas supply line and a gas supply valve (8). One end of the gas supply line is connected to the exhaust line (721), and the other end is connected to the air inlet of the cooling compressor (5). The gas supply valve (8) is located in the gas supply line.

5. The cooling system according to claim 4, characterized in that, The cooling system also includes an oil replenishment line (91) and an oil replenishment valve (92). The oil replenishment line (91) connects the oil-cooled return line (71) to the cooling compressor (5), and the oil replenishment valve (92) is located on the oil replenishment line (91).

6. The cooling system according to claim 1, characterized in that, The cooling assembly (4) includes an electronic expansion valve (41) and / or an orifice plate (42) disposed in the first cooling pipe (31).

7. A heat pump unit, characterized in that, Includes the cooling system according to any one of claims 1 to 6.

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