Air-cooled oil-free magnetic suspension centrifugal water cooling system and cooling method

Abstract

The invention discloses an air-cooled oil-free magnetic suspension centrifugal water cooling system and a cooling method, and belongs to the technical field of refrigeration air conditioner cooling systems. Comprising a mechanical refrigeration circulation system module, a natural cooling circulation system module and a spraying water circulation system module. The mechanical refrigeration circulation system module comprises a compressor, an air-cooled condenser, a liquid storage device, an economizer assembly and an evaporator. The natural cooling circulation system module comprises a natural cooling fin coil, a natural cooling water inlet header pipe, a natural cooling water outlet header pipe, an electric two-way valve, a water three-way valve, a natural cooling butterfly valve, an exhaust ball valve and an evaporator; the spraying water circulation system module comprises a spraying assembly, a spraying water tank, a spraying water circulation pump, a spraying water supply pipe, a spraying water collection disc and a spraying water drainage pipe. According to the air-cooling oil-free magnetic suspension centrifugal water cooling system, the advanced oil-free magnetic suspension compressor technology is adopted, the whole system is in an oil-free design, and a more efficient, energy-saving and low-noise water cooling solution is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration and air conditioning cooling systems, and in particular to an air-cooled oil-free magnetic suspension centrifugal chilled water system and a cooling method. Background Art

[0002] At present, with the rapid progress and development of science and technology, science and technology are empowering new quality productivity. The world is gradually entering a new era of AI technology. With the rapid development of the global digital economy, data centers, as the underlying support of the digital industry, have also ushered in a golden period of development. However, a large amount of cloud computing has made data centers a high-energy-consuming industry, and the high-density heat cooling and heat dissipation of their equipment has simultaneously become the focus and hot spot of the refrigeration and air-conditioning industry.

[0003] With the increasing global requirements for energy efficiency and energy conservation and the advancement of the dual carbon policy, the refrigeration industry has upgraded the energy efficiency standards for refrigeration equipment, continuously promoting the continuous innovation of refrigeration technology and refrigeration equipment, aiming to solve the limitations of traditional chilled water systems in terms of product energy efficiency, environmental friendliness, operating costs, cooling effects and application scenario limitations.

[0004] Traditional chilled water system solutions are now unable to meet the needs of high-density heat cooling and heat dissipation in emerging industries such as data centers. In this context, developing a new cooling water system to provide a more efficient, energy-saving, low-noise and lower maintenance and operating cost chilled water cooling solution to meet the cooling needs of emerging application scenarios such as data centers is an issue that needs to be addressed urgently. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides an air-cooled oil-free magnetically suspended centrifugal chilled water system and a cooling method, which can provide a chilled water cooling solution that is more efficient, energy-saving, low-noise and has lower maintenance and operation costs.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: An air-cooled oil-free magnetic suspension centrifugal chilled water system, comprising a mechanical refrigeration circulation system module, a natural cooling circulation system module and a spray water circulation system module: The mechanical refrigeration cycle system module includes a compressor, an air-cooled condenser, a liquid receiver, an economizer assembly, and an evaporator; The natural cooling circulation system module includes a natural cooling fin coil, a natural cooling water inlet main pipe, a natural cooling water outlet main pipe, an electric two-way valve, a water three-way valve, a natural cooling butterfly valve, an exhaust ball valve and an evaporator; The spray water circulation system module includes a spray assembly, a spray water tank, a spray water circulation pump, a spray water supply pipe, a spray water collection tray, and a spray drain pipe; The exhaust port of the compressor is connected to the inlet of the air-cooled condenser through a valve assembly, and the outlet of the air-cooled condenser is connected to the main-side inlet of the economizer assembly through a liquid receiver; The suction port of the compressor is connected to the outlet of the evaporator, the gas make-up port of the compressor is connected to the secondary-side outlet of the economizer assembly, and the liquid injection port of the compressor is connected to the outlet of the air-cooled condenser; The main circulation outlet of the economizer assembly is connected to the inlet of the evaporator through a valve assembly.

[0007] Furthermore, the compressor is a magnetic levitation oil-free centrifugal compressor. The compressor has a total of 4 interfaces. The suction interface and the exhaust interface of the compressor are respectively connected to the outlet of the evaporator and the inlet of the air-cooled condenser. The gas make-up port of the compressor is connected to the secondary-side outlet of the economizer assembly, and the liquid injection port of the compressor is connected to the outlet of the air-cooled condenser.

[0008] Furthermore, the air-cooled condenser is arranged symmetrically left and right in a V shape and uses internally threaded heat exchange tubes. An EC DC fan is provided at the upper end of the air-cooled condenser. A high-pressure solenoid valve is provided on the high-pressure inlet pipe of the air-cooled condenser, and a system safety relief valve is provided on the gas collecting main pipe of the air-cooled condenser.

[0009] Furthermore, the liquid receiver is arranged above the liquid high-pressure pipeline. The liquid inlet and outlet of the liquid receiver are respectively connected to the air-cooled condenser and the economizer assembly, and are used for storing high-pressure liquid refrigerant.

[0010] Furthermore, the economizer assembly includes a plate heat exchanger economizer, an economizer bypass ball valve, a bypass electronic expansion valve, an evaporation liquid supply sight glass, a main circuit electronic expansion valve, and an evaporation liquid supply pipeline ball valve, which form an economizer gas make-up cycle. The economizer gas make-up cycle adopts a downstream liquid extraction method. The secondary side uses an electronic expansion valve for throttling. A liquid supply temperature sensor and a gas make-up temperature sensor are respectively provided on the liquid supply pipe and the gas make-up outlet of the secondary side of the gas make-up cycle.

[0011] Furthermore, the evaporator is a flooded evaporator and uses internally threaded heat exchange tubes. The water-side water chamber is designed in a single-pass series connection. The liquid inlet and outlet of the evaporator are respectively connected to the main circuit electronic expansion valve and the suction port of the compressor. Inlet and outlet water temperature sensors are provided on the inlet and outlet water pipe connections of the evaporator. A suction manual butterfly valve connected to the suction port of the evaporator is provided at the middle position of the upper end of the evaporator. The interface of the suction manual butterfly valve is connected to the suction port of the compressor to form a suction circulation loop.

[0012] A cooling method for an air-cooled oil-free magnetic levitation centrifugal chiller system includes the following three cooling modes: Method 1: Mechanical refrigeration cycle system cooling mode. The high-pressure liquid refrigerant after being condensed by the air-cooled condenser is divided into two paths from the high-pressure liquid collecting pipe group: The first path is the liquid spraying circulation branch, which is used to reduce the temperature of the compressor coil; The second path is the main measurement circulation loop, which realizes gas replenishment and enthalpy increase; Method 2: The cooling mode of the natural cooling circulation system includes three working sub-modes: the full natural cooling sub-mode, the partial natural cooling sub-mode, and the full non-natural cooling sub-mode; Method 3: The cooling mode of the spray water circulation system. The spray water after heat exchange through the natural cooling finned coil is sent back to the spray water tank through the spray water collecting tray, and cooling is achieved through the circulation of the spray water.

[0013] Furthermore, in the full natural cooling sub-mode, when the ambient temperature is lower than a certain value of the unit return water temperature, the full natural cooling sub-mode is turned on. In this mode, the cooling mode of the mechanical refrigeration circulation system is in the off state, and all the cooling capacity required by the user is provided by the natural cooling finned coil.

[0014] Furthermore, in the partial natural cooling sub-mode, this mode is turned on in the transition season. The cooling mode of the mechanical refrigeration circulation system is turned on and in normal working state. The cooling capacity required by the user is preferentially provided by the natural cooling finned coil, and the remaining part of the cooling capacity is provided by the mechanical refrigeration circulation. The specific working path of the natural cooling circulation is the same as that of the full natural cooling sub-mode.

[0015] Furthermore, in the full non-natural cooling sub-mode, while the cooling mode of the mechanical refrigeration circulation system is turned on and running, the circulating water passes through the cooling mode of the mechanical refrigeration circulation system and is completely cooled by the mechanical refrigeration circulation.

[0016] In summary, compared with the prior art, the beneficial effects of the above technical solutions are as follows: (1) The air-cooled oil-free magnetic levitation centrifugal chiller system of the present application adopts the advanced oil-free magnetic levitation compressor technology, which is energy-efficient and the energy efficiency of the unit far exceeds the national first-level energy efficiency. The nominal refrigeration performance coefficient COP and the cooling season performance coefficient CSPF are as high as 3.84 and 5.54 respectively. Compared with the traditional refrigeration system, the energy efficiency can be saved by 30% - 40%. The magnetic levitation compressor uses the magnetic levitation technology to eliminate the mechanical friction of the traditional compressor, reduce the energy loss and wear, and thus improve the operation efficiency and reliability of the system. The entire system is oil-free designed, eliminating the oil management system of conventional refrigeration, reducing the maintenance requirements and extending the service life of the equipment, providing a more efficient, energy-saving, low-noise and lower maintenance and operation cost chiller cooling solution; (2) This application has a natural cooling function. The chilled water system uses outdoor cold air to lower the chilled water temperature through a natural cooling cycle, thereby minimizing reliance on the mechanical self-cooling of the compressor. When the outdoor ambient temperature is lower than the system return water temperature, the natural cooling mode is turned on, which can achieve two functions: full natural cooling and partial natural cooling. The chilled water system uses outdoor air for heat exchange, without or partially requiring the compressor to work, thereby improving the system's energy efficiency. When the ambient temperature is low enough, the chilled water system can completely use natural cooling to provide the required cooling capacity, stop the compressor mechanical refrigeration system, and only run the fan, greatly reducing power consumption. Natural cooling realizes the cooling function of the magnetic suspension chilled water system at an ambient temperature as low as -18°C, and greatly improves the unit's energy efficiency under low temperature conditions. (3) The present application has a spray function. Spray cooling increases the heat exchange effect of the coil surface by evenly spraying water mist on the surface of the condenser coil. The evaporation of the water mist takes away more heat, thereby further reducing the condensation temperature and improving the condensation efficiency. This function enables the air-cooled magnetic levitation system to operate efficiently and stably in an environment as high as 52°C. (4) The air-cooled oil-free magnetically levitated centrifugal chilled water system involved in this application can be restored to the state before power failure within 3 minutes, minimizing the increase in chilled water temperature, and can provide a reliable cooling solution for application scenarios such as data centers that have extremely high requirements for cooling systems. The unit uses R134a refrigerant with zero ozone depletion potential (ODP) and will not cause damage to the ozone layer; R513A and R1234ze refrigerants can be selected with low GWP values, which are more low-carbon and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the mechanical refrigeration cycle system of the air-cooled oil-free magnetic levitation centrifugal chilled water system in this application; Figure 2 A flow chart of a mechanical refrigeration cycle of an air-cooled oil-free magnetically suspended centrifugal chilled water system in this application; Figure 3 This is a schematic diagram of the natural cooling circulation system of the air-cooled oil-free magnetic levitation centrifugal chilled water system in this application; Figure 4 This is a natural cooling cycle flow chart of the air-cooled oil-free magnetic levitation centrifugal chilled water system in this application; Figure 5 This is a cycle flow chart of a completely natural cooling sub-mode in a natural cooling cycle of an air-cooled oil-free magnetically suspended centrifugal chiller in this application; Figure 6 This is a schematic diagram of the spray water circulation system of the air-cooled oil-free magnetic levitation centrifugal chilled water system in this application; Figure 7 This is a spray water circulation flow chart of the air-cooled oil-free magnetic levitation centrifugal chilled water system in this application.

[0018] Description of reference numerals: 1. Compressor; 2. Exhaust shut-off valve; 3. First high-pressure side three-way valve; 4. High-pressure solenoid valve; 5. EC DC fan; 6. Air-cooled condenser; 7. System safety relief valve; 8. Condensing pressure sensor; 9. Coil temperature sensor; 10. Condenser outlet check valve; 11. High-pressure liquid collecting pipe group; 12. Compression liquid injection ball valve; 13. Liquid injection filter; 14. Liquid injection sight glass; 15. Angle valve; 16. Liquid receiver; 17. Plate heat exchanger economizer; 18. Economizer bypass ball valve; 19. Bypass electronic expansion valve; 20. Evaporation liquid supply sight glass; 21. Main circuit electronic expansion valve; 22. Evaporation liquid supply pipeline ball valve; 23. Evaporation angle valve; 24. Evaporator; 25. Liquid level sensor; 26. Evaporation pressure sensor; 27. Evaporation safety relief valve; 28. Cut-in ball valve; 29. Electric cut-in regulating valve; 30. Suction manual butterfly valve; 31. Evaporation liquid supply three-way; 32. User terminal; 33. Inlet pipe exhaust ball valve; 34. Inlet water drain valve; 35. Natural cooling total inlet water three-way; 36. Electric two-way valve I; 37. Natural cooling coil inlet water three-way; 38. Natural cooling coil exhaust valve; 39. Natural cooling finned coil; 40. Natural cooling butterfly valve; 41. Electric two-way valve II; 42. Evaporation inlet water three-way; 43. Evaporation outlet pipe; 44. Evaporation inlet pipe; 45. Evaporation drain valve; 46. Spraying inlet pipe; 47. Spraying inlet ball valve; 48. Spraying inlet solenoid valve; 49. Spraying water tank; 50. Spraying water circulation pump; 51. Spraying water supply pipe; 52. Spraying water supply three-way; 53. Spraying shower head; 54. Spraying water collecting tray; 55. Spraying water collecting pipe; 56. Spraying overflow pipe; 57. Spraying drain ball valve; 58. Spraying drain solenoid valve; 59. Spraying drain three-way; 60. Spraying drain pipe. Detailed implementation manners

[0019] The principles and features of the present invention will be described below in conjunction with all the attached drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0020] An embodiment of the present invention discloses an air-cooled oil-free magnetic levitation centrifugal chiller system and a cooling method.

[0021] An air-cooled oil-free magnetic levitation centrifugal chiller system includes a mechanical refrigeration cycle system module, a natural cooling cycle system module, and a spraying water circulation system module.

[0022] Referring to Figure 1 and Figure 2 , the mechanical refrigeration cycle system module includes a compressor 1, an air-cooled condenser 6, a liquid receiver 16, an economizer assembly, and an evaporator 24.

[0023] In this embodiment, the mechanical refrigeration cycle system module of the air-cooled oil-free magnetic levitation centrifugal chiller system includes: a magnetic levitation compressor 1, a multi-functional exhaust stop valve 2, a first high-pressure side three-way valve 3, a high-pressure solenoid valve 4, an EC DC fan 5, an air-cooled condenser 6, a system safety relief valve 7, a condensing pressure sensor 8, a coil temperature sensor 9, a condenser outlet check valve 10, a high-pressure liquid collector group 11, a compression liquid injection ball valve 12, a liquid injection filter 13, a liquid injection sight glass 14, an angle valve 15, a liquid receiver 16, a plate heat exchanger economizer 17, an economizer bypass ball valve 18, a bypass electronic expansion valve 19, an evaporation liquid supply sight glass 20, a main circuit electronic expansion valve 21, an evaporation liquid supply pipeline ball valve 22, an evaporation angle valve 23, an evaporator 24, a liquid level sensor 25, an evaporation pressure sensor 26, an evaporation safety relief valve 27, a cut-in ball valve 28, an electric cut-in regulating valve 29, a suction manual butterfly valve 30, and an evaporation liquid supply three-way valve 31.

[0024] The exhaust port of the compressor 1 is connected to the inlet of the air-cooled condenser 6 through a valve assembly. The outlet of the air-cooled condenser 6 is connected to the main-side inlet of the economizer assembly through the liquid receiver 16. The suction port of the compressor 1 is connected to the outlet of the evaporator 24. The gas replenishment port of the compressor 1 is connected to the auxiliary-side outlet of the economizer assembly. The liquid injection port of the compressor 1 is connected to the outlet of the air-cooled condenser 6. The main circulation outlet of the economizer assembly is connected to the inlet of the evaporator 24 through a valve assembly.

[0025] The compressor 1 is a magnetic levitation oil-free centrifugal compressor 1. The compressor 1 has a total of 4 interfaces. The suction interface and the exhaust interface of the compressor 1 are respectively connected to the outlet of the evaporator 24 and the inlet of the air-cooled condenser 6. The gas replenishment port of the compressor 1 is connected to the auxiliary-side outlet of the economizer assembly. The liquid injection port of the compressor 1 is connected to the outlet of the air-cooled condenser 6.

[0026] The air-cooled condenser 6 is arranged symmetrically left and right in a V shape and uses internally threaded heat exchange tubes. The EC DC fan 5 is provided at the upper end of the air-cooled condenser 6. The high-pressure solenoid valve 4 is provided on the high-pressure inlet pipe of the air-cooled condenser 6. The system safety relief valve 7 is provided on the gas collecting main pipe of the air-cooled condenser 6.

[0027] The liquid receiver 16 is arranged above the liquid high-pressure pipeline. The inlet and outlet of the liquid receiver 16 are respectively connected to the air-cooled condenser 6 and the economizer assembly, and are used for storing high-pressure liquid refrigerant.

[0028] The economizer assembly includes a plate heat exchanger economizer 17, an economizer bypass ball valve 18, a bypass electronic expansion valve 19, an evaporation liquid supply sight glass 20, a main circuit electronic expansion valve 21, and an evaporation liquid supply pipeline ball valve 22, which form an economizer gas replenishment cycle. The economizer gas replenishment cycle adopts a downstream liquid extraction method. The auxiliary side uses an electronic expansion valve for throttling. A liquid supply temperature sensor and a gas replenishment temperature sensor are respectively provided on the liquid supply pipe and the gas replenishment outlet of the auxiliary side of the gas replenishment cycle.

[0029] The evaporator 24 is a flooded evaporator 24, which adopts internally threaded heat exchange tubes. The water chamber on the water side is designed with a single-pass series connection. The liquid inlet and outlet of the evaporator 24 are respectively connected to the main electronic expansion valve 21 and the suction port of the compressor 1. Temperature sensors for inlet and outlet water are provided on the inlet and outlet water pipe connections of the evaporator 24. A suction manual butterfly valve 30 connected to the suction port of the evaporator 24 is provided at the middle position of the upper end of the evaporator 24. The interface of the suction manual butterfly valve 30 is connected to the suction port of the compressor 1 to form a suction circulation loop.

[0030] The exhaust port a of the above-mentioned magnetic levitation compressor 1 is connected to the inlets a and b of the air-cooled condenser 6 through the first high-pressure side three-way valve 3 (the second high-pressure side three-way valve). The outlets c and d of the air-cooled condenser 6 are connected to the high-pressure liquid collector group 11 through the condenser outlet check valve 10.

[0031] The high-pressure liquid refrigerant after being condensed by the air-cooled condenser 6 comes out of the high-pressure liquid collector group 11 and is divided into two paths: The first path is the liquid injection circulation branch. The high-pressure liquid refrigerant successively passes through the magnetic levitation compression liquid injection ball valve 12 and the liquid injection filter 13, and enters the inside of the magnetic levitation compressor 1 through the liquid injection port d of the magnetic levitation compressor 1 to reduce the temperature of the compressor 1 coil.

[0032] The second path is the main side circulation loop. The high-pressure liquid refrigerant enters the liquid receiver 16, and after flowing out from the port b of the liquid receiver 16, it is divided into two paths: one path is connected to the port a of the plate heat exchanger economizer 17 and enters the main side circulation of the plate heat exchanger economizer 17. The main path high-pressure liquid refrigerant exchanges heat with the medium-temperature and medium-pressure refrigerant in the auxiliary side circulation in the plate heat exchanger economizer 17 to form secondary subcooling. Then, the high-pressure subcooled liquid refrigerant flows out from the main side port b of the plate heat exchanger economizer 17, passes through the evaporation supply three-way valve 31, and then is throttled by the main electronic expansion valve 21 into a low-temperature and low-pressure gas-liquid two-phase refrigerant and enters the evaporator 24. The b and c interfaces of the evaporation supply three-way valve 31 are respectively connected to the liquid inlet ports d and e of the evaporator 24. The evaporation supply sight glass 20 and the evaporation angle valve 23 are respectively arranged before and after the electronic expansion valve on the liquid supply pipeline of the evaporator 24; the other path is connected to the auxiliary side inlet port c of the plate heat exchanger economizer 17 and enters the auxiliary side circulation of the plate heat exchanger economizer 17. The economizer auxiliary circuit ball valve 18 and the auxiliary electronic expansion valve 19 are arranged on the auxiliary side liquid supply return path of the plate heat exchanger economizer 17. The medium-pressure and medium-temperature refrigerant after being throttled by the auxiliary electronic expansion valve 19 exchanges heat with the high-temperature and high-pressure liquid refrigerant on the main side of the plate heat exchanger economizer 17 and then evaporates, and flows out from the port d of the plate heat exchanger economizer 17 and enters the gas supplement port c of the magnetic levitation compressor 1 to realize gas supplement and enthalpy increase.

[0033] The cut-in ball valve 28 is connected to the g port of the evaporator 24, then passes through the electric cut-in regulating valve 29 and is connected to the a port of the multi-functional exhaust shut-off valve, and is connected to the exhaust port a of the magnetic levitation compressor 1 through the b port of the multi-functional exhaust shut-off valve. The above components form the cut-in bypass regulating circulation loop of the magnetic levitation compressor 1.

[0034] The magnetic levitation compressor 1 is an oil-free magnetic levitation compressor 1. It adopts magnetic levitation technology to make the motor shaft levitate in the center, avoiding mechanical contact. The whole system is designed without oil, and there is no need to set up an oil separator and an oil return circulation.

[0035] The magnetic levitation compressor 1 is internally equipped with a variable frequency drive (VFD) and a soft starter, and the starting current is as low as 2A.

[0036] The evaporator 24 is a flooded evaporator 24. The left end of the evaporator 24 is the water side inlet and outlet interfaces a and b. Temperature sensors for inlet and outlet water are respectively arranged on the inlet and outlet pipes of the evaporator 24, and an evaporation pressure sensor 26 and an evaporation safety relief valve 27 are arranged on the container cylinder body. A liquid level sensor 25 is arranged at the right end of the evaporator 24 for controlling the internal liquid level of the evaporator 24. Interfaces h1 and h2 are reserved on the upper right side of the evaporator 24 and are respectively connected to the a and b interfaces of the liquid level sensor 25. A cut-in ball valve 28 is arranged on the connecting pipeline between the liquid level sensor 25 and the evaporator 24 for the maintenance and replacement of the liquid level sensor 25. An air suction port f is arranged at the middle position of the upper end of the evaporator 24 and is connected to the b interface of the air suction manual butterfly valve 30. The a interface of the air suction manual butterfly valve 30 is connected to the air suction port b of the magnetic levitation compressor 1 to form an air suction circulation loop.

[0037] The evaporator 24 adopts high-efficiency enhanced heat exchange tubes, significantly improving the heat exchange efficiency.

[0038] The evaporator 24 is provided with a container cylinder wall baffle and an air suction port baffle, effectively preventing the phenomena of air suction with liquid and liquid level fluctuation, ensuring the system stability and operation reliability.

[0039] The air-cooled condenser 6 is arranged in a V-shaped left-right symmetric layout, adopts 9.52mm high-efficiency internal thread heat exchange tubes, an EC DC fan 5 is arranged at its upper end, and a high-pressure solenoid valve 4 is arranged on its high-pressure inlet pipe for controlling the on-off of high-pressure gas. A system safety relief valve 7 is arranged on the gas collecting main pipe for the pressure protection of the high-pressure side of the refrigeration system.

[0040] The plate heat exchanger economizer 17, the economizer bypass ball valve 18, the bypass electronic expansion valve 19, the evaporation liquid supply sight glass 20, the main path electronic expansion valve 21, and the evaporation liquid supply pipeline ball valve 22 form the economizer assembly and the economizer gas supplement circulation.

[0041] The economizer air-inlet cycle adopts the downstream liquid-taking method. The auxiliary side uses an electronic expansion valve for throttling. A liquid supply temperature sensor and an air-inlet temperature sensor are respectively set on the liquid supply pipe of the auxiliary side of the air-inlet cycle and the air-inlet outlet. The opening degree of the electronic expansion valve on the auxiliary side is controlled by the temperature difference between the two, so as to control the air-inlet volume, and then achieve the best air-inlet and enthalpy-increasing effect.

[0042] For the mechanical refrigeration cycle system module of the above air-cooled oil-free magnetic levitation centrifugal chiller system, the refrigerant can adopt R134a refrigerant, or environmentally friendly refrigerants such as R513A and R1234ze with lower GWP values.

[0043] Refer to Figure 3 and Figure 4 、 Figure 5 The natural cooling cycle system module includes a natural cooling finned coil 39, a natural cooling water inlet main pipe, a natural cooling water outlet main pipe, an electric two-way valve, a water three-way valve, a natural cooling butterfly valve 40, an exhaust ball valve, and an evaporator 24.

[0044] The natural cooling cycle system module of the air-cooled oil-free magnetic levitation centrifugal chiller system includes: a user terminal 32, an inlet pipe exhaust ball valve 33, an inlet water drain valve 34, a natural cooling total inlet three-way 35, an electric two-way valve 1 36, a natural cooling coil inlet three-way 37, a natural cooling coil exhaust valve 38, a natural cooling finned coil 39, a natural cooling butterfly valve 40, an electric two-way valve 2 41, an evaporation inlet three-way 42, an evaporation outlet pipe 43, an evaporation inlet pipe 44, an evaporation drain valve 45, and an evaporator 24.

[0045] The inlet a of the natural cooling finned coil 39 is connected to the b and c ports of the natural cooling coil inlet three-way 37, and its outlet b and c are merged and then connected to the port a of the natural cooling butterfly valve 40; a natural cooling coil exhaust valve 38 is set on the gas collecting pipe of the natural cooling finned coil 39. The natural cooling coil exhaust valve 38 is located at the highest point of the natural cooling cycle system and is used for exhausting the gas in the system.

[0046] The electric two-way valve 1 36 is set between the natural cooling total inlet three-way 35 and the natural cooling coil inlet three-way 37. Its a-end inlet is connected to the c port of the natural cooling total inlet three-way 35, and the b port is connected to the a port of the natural cooling coil inlet three-way 37. The electric two-way valve 2 41 is set between the natural cooling total inlet three-way 35 and the evaporation inlet three-way 42. Its a-end inlet is connected to the b port of the natural cooling total inlet three-way 35, and the b port is connected to the a port of the evaporation inlet three-way 42.

[0047] The port a of the user terminal 32 is connected to the port a of the natural cooling main inlet tee 35. A water temperature sensor, an inlet pipe exhaust ball valve 33, and an inlet and drain valve 34 are sequentially arranged on the inlet pipe between them. Among them, the inlet pipe exhaust ball valve 33 is installed at the high point of the inlet pipe of the natural cooling circulation system module for discharging air from the system, and the inlet and drain valve 34 is installed at the low point of the inlet pipe for draining the water in the system to prevent the water system from freezing in winter under low ambient temperature.

[0048] The natural cooling circulation system module of the above air-cooled oil-free magnetic levitation centrifugal chiller system has three working modes: full natural cooling sub-mode, partial natural cooling sub-mode, and full non-natural cooling sub-mode.

[0049] Mode 1, the full natural cooling sub-mode cycle is as follows: When the ambient temperature is lower than a certain value of the unit return water temperature, the full natural cooling sub-mode is turned on.

[0050] In this operating mode, the electric two-way valve 1 36 is opened, the electric two-way valve 2 41 is closed, the natural cooling butterfly valve 40 is opened, and the return water is completely cooled by the natural cooling finned coil 39. The cooling water enters the evaporator 24 through the evaporation inlet pipe 44, and then through the evaporation outlet pipe 43 to supply cold water to the user terminal 32.

[0051] In this mode, the magnetic levitation compressor 1 is turned off, the mechanical refrigeration cycle is in the off state, and all the cooling capacity required by the user is provided by the natural cooling finned coil 39.

[0052] Mode 2, the partial natural cooling sub-mode cycle is as follows: This operating mode is only turned on in the transitional season.

[0053] In this operating mode, the electric two-way valve 1 36 is opened, the electric two-way valve 2 41 is closed, and the natural cooling butterfly valve 40 is opened. The above valves are in the same action state as the full natural cooling sub-mode. The return water is partially cooled by the natural cooling finned coil 39. The cooling water then enters the evaporator 24 through the evaporation inlet pipe 44, and then through the evaporation outlet pipe 43 to supply cold water to the user.

[0054] In this mode, the magnetic levitation compressor 1 is turned on synchronously, the mechanical refrigeration cycle is in the normal operating state. The cooling capacity required by the user is preferentially provided by the natural cooling finned coil 39, and the remaining part of the cooling capacity is provided by the mechanical refrigeration cycle. The specific working path of the natural cooling cycle is the same as that of the full natural cooling sub-mode.

[0055] Mode 3, the full non-natural cooling sub-mode cycle (mechanical refrigeration cycle) is as follows: The magnetic levitation compressor 1 is started. The high-temperature and high-pressure gaseous refrigerant discharged from the outlet of the magnetic levitation compressor 1 enters the air-cooled condenser 6 through the multi-functional exhaust stop valve 2. The high-temperature and high-pressure liquid refrigerant after condensation and cooling is partially stored in the liquid receiver 16. The liquid refrigerant is subcooled for the second time through the plate heat exchanger economizer 17. The low-temperature and low-pressure gas-liquid two-phase refrigerant after throttling by the main circuit electronic expansion valve 21 enters the evaporator 24 to evaporate and absorb heat. The low-pressure superheated gaseous refrigerant coming out of the outlet of the evaporator 24 enters the suction port of the magnetic levitation compressor 1. The compressor 1 does work to compress the refrigerant into a high-temperature and high-pressure gaseous superheated refrigerant, which is discharged through the exhaust port of the magnetic levitation compressor 1 and enters the air-cooled condenser 6 again for cooling and condensation, completing the above mechanical refrigeration cycle reciprocally. The specific circulation process of the mechanical refrigeration is as Figure 4 shown.

[0056] For the above-mentioned fully non-natural cooling sub-mode cycle (mechanical refrigeration cycle), while the mechanical refrigeration cycle is started and running, the electric two-way valve 1 36 is closed, the electric two-way valve 2 41 is opened, and the natural cooling butterfly valve 40 is closed. The return water does not pass through the natural cooling finned coil 39 for cooling and directly enters the evaporator 24. The circulating water is cooled completely through the mechanical refrigeration cycle.

[0057] Referring to Figure 6 and Figure 7 , the spray water circulation system module includes a spray assembly, a spray water tank 49, a spray water circulation pump 50, a spray water supply pipe 51, a spray water collecting tray 54, and a spray drain pipe 60, which are used to cool down the natural cooling finned coil 39.

[0058] In this embodiment, the spray water circulation system module of the air-cooled oil-free magnetic levitation centrifugal chiller system includes: a spray water inlet pipe 46, a spray water inlet ball valve 47, a spray water inlet solenoid valve 48, a spray water tank 49, a spray water circulation pump 50, a spray water supply pipe 51, a spray water supply tee 52, a spray shower head 53, a spray water collecting tray 54, a spray water collecting pipe 55, a spray overflow pipe 56, a spray drain ball valve 57, a spray drain solenoid valve 58, a spray drain tee 59, and a spray drain pipe 60.

[0059] The spray water tank 49 is placed at the bottom of the unit equipment. The spray water circulation pump 50 is built in it. The water inlet a of the spray water tank 49 is connected to the b port of the spray water inlet solenoid valve 48. The b port of the spray water tank 49 is connected to the spray shower head 53 through the spray water supply pipe 51 and the spray water supply tee 52. The drain port d of the spray water tank 49 is connected to the b port of the spray drain solenoid valve 58 through the spray drain ball valve 57 for draining the spray water tank 49. The water return port e of the spray water tank 49 is connected to the spray water collecting tray 54 through the spray water collecting pipe 55.

[0060] The spray shower head 53 is placed on the upper part of the air-cooled condenser 6 and is used to evenly spray the water in the spray water tank 49 onto the natural cooling finned coil 39. The spray water collecting tray 54 is located at the bottom of the air-cooled condenser 6 and is used to collect the spray water after heat exchange through the natural cooling finned coil 39, and then send it back to the spray water tank 49 through the spray water collecting tray 54.

[0061] A cooling method for an air-cooled oil-free magnetic levitation centrifugal chiller system includes the following three cooling modes: Method 1: Mechanical refrigeration cycle system cooling mode. After being condensed by the air-cooled condenser 6, the high-pressure liquid refrigerant comes out of the high-pressure liquid collecting pipe group 11 and is divided into two paths: The first path is the liquid injection circulation branch, which is used to reduce the coil temperature of the compressor 1; The second path is the main measurement circulation loop, which realizes gas injection and enthalpy increase; Method 2: Natural cooling cycle system cooling mode, including three working sub-modes: full natural cooling sub-mode, partial natural cooling sub-mode, and full non-natural cooling sub-mode; Method 3: Spray water circulation system cooling mode. The spray water after heat exchange through the natural cooling finned coil 39 is sent back to the spray water tank 49 through the spray water collecting tray 54, and cooling is achieved through the circulation of the spray water.

[0062] In the full natural cooling sub-mode, when the ambient temperature is lower than a certain value of the unit return water temperature, the full natural cooling sub-mode is turned on. In this mode, the mechanical refrigeration cycle system cooling mode is in the off state, and all the cooling capacity required by the user is provided by the natural cooling finned coil 39.

[0063] In the partial natural cooling sub-mode, this mode is turned on in the transitional season. The mechanical refrigeration cycle system cooling mode is turned on and operates normally. The cooling capacity required by the user is preferentially provided by the natural cooling finned coil 39, and the remaining part of the cooling capacity is provided by the mechanical refrigeration cycle. The specific working path of the partial natural cooling cycle is the same as that of the full natural cooling sub-mode.

[0064] In the full non-natural cooling sub-mode, while the mechanical refrigeration cycle system cooling mode is turned on and running, the circulating water passes through the mechanical refrigeration cycle system cooling mode and is completely cooled by the mechanical refrigeration cycle.

[0065] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An air-cooled oil-free magnetic levitation centrifugal chiller system, characterized in that: It includes a mechanical refrigeration cycle system module, a natural cooling cycle system module, and a spray water circulation system module: The mechanical refrigeration cycle system module includes a compressor (1), an air-cooled condenser (6), a liquid receiver (16), an economizer assembly, and an evaporator (24); The natural cooling cycle system module includes a natural cooling finned coil (39), a natural cooling water inlet main pipe, a natural cooling water outlet main pipe, an electric two-way valve, a water three-way valve, a natural cooling butterfly valve (40), an exhaust ball valve, and an evaporator (24); The spray water circulation system module includes a spray assembly, a spray water tank (49), a spray water circulation pump (50), a spray water supply pipe (51), a spray water collection tray (54), and a spray water drain pipe (60); The exhaust port of the compressor (1) is connected to the inlet of the air-cooled condenser (6) through a valve assembly, and the outlet of the air-cooled condenser (6) is connected to the main-side inlet of the economizer assembly through the liquid receiver (16); The suction port of the compressor (1) is connected to the outlet of the evaporator (24), the gas replenishing port of the compressor (1) is connected to the secondary-side outlet of the economizer assembly, and the liquid injection port of the compressor (1) is connected to the outlet of the air-cooled condenser (6); The main circulation outlet of the economizer assembly is connected to the inlet of the evaporator (24) through a valve assembly.

2. The air-cooled oil-free magnetic levitation centrifugal chiller system according to claim 1, characterized in that: The compressor (1) is a magnetic levitation oil-free centrifugal compressor (1). The compressor (1) has a total of 4 interfaces. The suction interface and the exhaust interface of the compressor (1) are respectively connected to the outlet of the evaporator (24) and the inlet of the air-cooled condenser (6). The gas replenishing port of the compressor (1) is connected to the secondary-side outlet of the economizer assembly, and the liquid injection port of the compressor (1) is connected to the outlet of the air-cooled condenser (6).

3. A kind of air-cooled oil-free magnetic levitation centrifugal chiller system according to claim 1, characterized in that: The air-cooled condenser (6) is arranged symmetrically left and right in a V shape and uses internally threaded heat exchange tubes. An EC DC fan (5) is provided at the upper end of the air-cooled condenser (6). A high-pressure solenoid valve (4) is provided on the high-pressure inlet pipe of the air-cooled condenser (6), and a system safety relief valve (7) is provided on the gas collection main pipe of the air-cooled condenser (6).

4. The air-cooled oil-free magnetic levitation centrifugal chiller system according to claim 1, characterized in that: The liquid receiver (16) is arranged above the liquid high-pressure pipeline. The liquid inlet and outlet of the liquid receiver (16) are respectively connected to the air-cooled condenser (6) and the economizer assembly, and are used to store high-pressure liquid refrigerant.

5. A kind of air-cooled oil-free magnetic levitation centrifugal chiller system according to claim 1, characterized in that: The economizer assembly includes a plate heat exchanger economizer (17), an economizer bypass ball valve (18), a bypass electronic expansion valve (19), an evaporation liquid supply sight glass (20), a main path electronic expansion valve (21), and an evaporation liquid supply pipeline ball valve (22), which form an economizer gas replenishing cycle. The economizer gas replenishing cycle adopts a downstream liquid extraction method. The secondary side uses an electronic expansion valve for throttling. A liquid supply temperature sensor and a gas replenishing temperature sensor are respectively provided on the liquid supply pipe and the gas replenishing outlet of the secondary side of the gas replenishing cycle.

6. The air-cooled oil-free magnetic levitation centrifugal chiller system according to claim 1, characterized in that: The evaporator (24) is a flooded evaporator (24) that uses internally threaded heat exchange tubes. The water chamber on the water side is designed with a single-flow series connection. The liquid inlet and outlet of the evaporator (24) are respectively connected to the main electronic expansion valve (21) and the suction port of the compressor (1). Temperature sensors for inlet and outlet water are provided on the inlet and outlet water pipe connections of the evaporator (24). A suction manual butterfly valve (30) connected to the suction port of the evaporator (24) is provided at the middle position of the upper end of the evaporator (24). The interface of the suction manual butterfly valve (30) is connected to the suction port of the compressor (1) to form a suction circulation loop.

7. A cooling method for an air-cooled oil-free magnetic levitation centrifugal chiller system according to any one of claims 1 to 6, characterized in that, It includes the following three cooling modes: Method 1: Mechanical refrigeration cycle system cooling mode. After being condensed by the air-cooled condenser (6), the high-pressure liquid refrigerant comes out of the high-pressure liquid collecting pipe group (11) and is divided into two paths: The first path is the liquid injection circulation branch for reducing the coil temperature of the compressor (1); The second path is the main measurement circulation loop for realizing gas injection and enthalpy increase; Method 2: Natural cooling cycle system cooling mode, which includes three working sub-modes: full natural cooling sub-mode, partial natural cooling sub-mode, and full non-natural cooling sub-mode; Method 3: Spray water circulation system cooling mode. The spray water after heat exchange through the natural cooling finned coil (39) is sent back to the spray water tank (49) through the spray water collecting tray (54), and cooling is achieved through the circulation of the spray water.

8. A cooling method for an air-cooled oil-free magnetic levitation centrifugal chiller system according to claim 7, characterized in that: In the full natural cooling sub-mode, when the ambient temperature is lower than a certain value of the unit return water temperature, the full natural cooling sub-mode is turned on. In this mode, the mechanical refrigeration cycle system cooling mode is in the off state, and all the cooling capacity required by the user is provided by the natural cooling finned coil (39).

9. A cooling method for an air-cooled oil-free magnetic levitation centrifugal chiller system according to claim 7, characterized in that: In the partial natural cooling sub-mode, this mode is turned on during the transitional season. The mechanical refrigeration cycle system cooling mode is turned on and operates normally. The cooling capacity required by the user is preferentially provided by the natural cooling finned coil (39), and the remaining part of the cooling capacity is provided by the mechanical refrigeration cycle. The specific working path of the natural cooling cycle is the same as that of the full natural cooling sub-mode.

10. A cooling method for an air-cooled oil-free magnetic levitation centrifugal chiller system according to claim 7, characterized in that: In the full non-natural cooling sub-mode, while the mechanical refrigeration cycle system cooling mode is turned on and operating, the circulating water passes through the mechanical refrigeration cycle system cooling mode and is completely cooled by the mechanical refrigeration cycle.

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