EP4286771A1 - Kühlsystem - Google Patents

Kühlsystem Download PDF

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Publication number
EP4286771A1
EP4286771A1 EP23176358.2A EP23176358A EP4286771A1 EP 4286771 A1 EP4286771 A1 EP 4286771A1 EP 23176358 A EP23176358 A EP 23176358A EP 4286771 A1 EP4286771 A1 EP 4286771A1
Authority
EP
European Patent Office
Prior art keywords
compressor
oil
refrigeration system
phase refrigerant
refrigerant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23176358.2A
Other languages
English (en)
French (fr)
Inventor
Wei Zhang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Carrier Corp
Original Assignee
Carrier Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Carrier Corp filed Critical Carrier Corp
Publication of EP4286771A1 publication Critical patent/EP4286771A1/de
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/006—Accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/006—Cooling of compressor or motor
    • F25B31/008—Cooling of compressor or motor by injecting a liquid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/002—Lubrication
    • F25B31/004—Lubrication oil recirculating arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/02—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/04—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type
    • F25B1/053—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type of turbine type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2341/00—Details of ejectors not being used as compression device; Details of flow restrictors or expansion valves
    • F25B2341/001—Ejectors not being used as compression device
    • F25B2341/0011—Ejectors with the cooled primary flow at reduced or low pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2341/00—Details of ejectors not being used as compression device; Details of flow restrictors or expansion valves
    • F25B2341/001—Ejectors not being used as compression device
    • F25B2341/0015—Ejectors not being used as compression device using two or more ejectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2341/00—Details of ejectors not being used as compression device; Details of flow restrictors or expansion valves
    • F25B2341/001—Ejectors not being used as compression device
    • F25B2341/0016—Ejectors for creating an oil recirculation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/23—Separators

Definitions

  • the present invention relates to the field of refrigeration systems, and is applicable in particular to oil-lubricated refrigeration systems and oil-free refrigeration systems.
  • the refrigeration systems used in the fields of industrial equipment manufacturing, heating and heat exchange requires increasingly high energy efficiency.
  • economizers are usually configured in refrigeration systems to improve the energy efficiency coefficient thereof the refrigeration systems.
  • the refrigerant system comprises a main flow path, the main flow path comprising a compressor 11, a condenser 12, a throttling device 13, an evaporator 14 and other components that are fluidly communicated, with refrigerant circulating through them.
  • the refrigeration system 10 combines an economizer 15 with an expansion valve 16 to provide intermediate gas supply to the compressor 11 to improve cycle efficiency.
  • an additional oil return system that includes one or more ejectors 27 and an oil tank 28 is required for the refrigeration system 20.
  • the ejector 27, by means of high-pressure refrigerant gas from the outlet of the compressor 21, ejects oil-mixed refrigerant from the oil-rich layer zone of the refrigeration system, such as the evaporator 24, while the oil tank 28 receives the output fluid from the output port of the ejector 27 and delivers the filtered lubricant oil to the compressor bearing chamber through an oil pump so as to lubricate the compressor bearings.
  • the objective of at least preferred embodiments of the present invention is to solve or at least alleviate problems existing in the prior art.
  • a refrigeration system comprising:
  • a plurality of ejectors are provided and are arranged in parallel, wherein high-pressure fluid inlets of the plurality of ejectors are connected near the bottom of the condenser and fluid suction inlets of the plurality of ejectors are connected near the internal liquid level of the evaporator.
  • the compressor is an oil-free two-stage centrifugal compressor.
  • the compressor comprises an electromagnetic bearing, a gas bearing or a refrigerant-lubricated bearing.
  • a refrigeration system comprising:
  • an oil pump is provided in the oil tank for delivering oil in the oil tank to the compressor bearing chamber.
  • a heater for heating up oil is provided in the oil tank.
  • a plurality of ejectors are provided and are arranged in parallel, wherein high-pressure fluid inlets of the plurality of ejectors are connected near the bottom of the condenser and fluid suction inlets of the plurality of ejectors are connected near the internal liquid level of the evaporator.
  • the oil tank is a container, wherein an inlet port of the oil tank is connected to a range from near the internal liquid level of the separator to the bottom of the separator.
  • the compressor is an oil-lubricated two-stage centrifugal compressor.
  • the refrigeration system according to the present invention has a lot of advantages such as high universality and high energy efficiency.
  • an oil-free compressor is used in the system (i.e., without oil return)
  • it not only simplifies the structure but also lowers the manufacturing cost.
  • an oil-lubricated compressor is used in the system (i.e., with oil return)
  • it is only necessary to add the oil tank and the corresponding oil return pipeline.
  • the oil concentration and oil temperature are controllable and the oil return is stable, thus ensuring the normal operation of oil-lubricated bearings.
  • the refrigeration system 100 comprises a main flow path.
  • the main flow path comprises a compressor 110, a condenser 120, a throttling device 130, and an evaporator 140 that are fluidly communicated, with refrigerant circulating through them, wherein the compressor 110 comprises at least a first compression stage and a second compression stage.
  • the compressor 110 may be a high-speed direct-drive compressor in which the motor shaft is directly connected to the compressor impeller without a gearbox.
  • the compressor 110 may include, for example, a compressor inlet 111, a compressor outlet 112, a motor housing 113, and a gas supply port 114 between the fluid outlet of the first compression stage and the fluid inlet of the second compression stage.
  • the compressor 110 can employ a two-stage centrifugal compressor without oil lubrication.
  • the compressor 110 includes an electromagnetic bearing, a gas bearing or a refrigerant-lubricated bearing for supporting the motor shaft that rotates at high speed.
  • the throttling device 130 may be an expansion valve, such as a mechanical expansion valve or an electronic expansion valve.
  • the refrigeration system 100 further comprises an ejector 150 and a separator 160.
  • the ejector 150 is configured to eject low-pressure refrigerant from the evaporator 140 by means of high-pressure refrigerant from the condenser 120 and to mix them into a medium-pressure gas-liquid two-phase refrigerant.
  • the separator 160 is arranged downstream of the ejector 150 in the direction of refrigerant flow for separating the medium-pressure gas-liquid two-phase refrigerant from the ejector 150 into gas-phase refrigerant and liquid-phase refrigerant.
  • the separator 160 delivers the gas-phase refrigerant separated to the gas supply port 114 between the fluid outlet of the first compression stage and the fluid inlet of the second compression stage in the compressor 110 through the flow path, such that the gas-phase refrigerant mixes with the output gas of the first compression stage and then enters the second compression stage for continued compression, thus saving part of the compression work.
  • the separator 160 delivers the liquid-phase refrigerant separated to a port on the motor housing 113 of the compressor 110 through the flow path, where the liquid-phase refrigerant is flash evaporated immediately due to a pressure drop. It can be seen that the rotor and stator in the motor housing 113 are cooled by flash evaporation to reduce the temperature.
  • the ejector 150 includes a high-pressure fluid inlet 151, a fluid suction inlet 152, and a fluid outlet 153.
  • the high-pressure fluid inlet 151 of the ejector 150 is connected near the bottom of the condenser 120 to receive high-pressure fluid.
  • the fluid suction inlet 152 of the ejector 150 is connected near the internal liquid level of the evaporator 140 to receive low-pressure fluid.
  • the fluid outlet 153 of the ejector 150 is connected to the separator 160 to separate the medium-pressure gas-liquid two-phase refrigerant mixed by the ejector 150 into gas-phase refrigerant and liquid-phase refrigerant.
  • high-pressure and low-pressure appearing in the text are relative concepts.
  • the pressure of the refrigerant fluid in the condenser 120 is generally greater than that of the refrigerant fluid in the evaporator 140, so that the ejector 150 receives "high-pressure” refrigerant fluid from the condenser 120 and a "low-pressure” refrigerant fluid from the evaporator 140. It is because of the pressure difference between the fluid of the condenser and that of the evaporator that it is possible for the ejector to mix the two fluids into a medium-pressure fluid by sucking the low-pressure fluid using the high-pressure fluid.
  • a plurality of ejectors can also be arranged, such as two, three or more.
  • the plurality of ejectors may be arranged in parallel and switched on and off electrically to control the flow of the gas-liquid two-phase refrigerant output, wherein the high-pressure fluid inlets of the plurality of ejectors are connected near the bottom of the condenser and the fluid suction inlets of the plurality of ejectors are connected near the internal liquid level of the evaporator.
  • the plurality of ejectors may be of the same size. Alternatively, each ejector may have a different size to accommodate system requirements for gas supply and motor cooling under different operating conditions.
  • the embodiments of the oil-free refrigeration system according to the present invention eliminates components such as economizers and electronic expansion valves in the prior art, thereby simplifying the structure of the system and lowering the manufacturing cost of the system.
  • the system utilizes the pressure difference between the condenser and the evaporator to produce a medium-pressure gas-liquid two-phase refrigerant, which is further separated by the separator into a gas-phase refrigerant for gas supply for the intermediate stage of the compressor and a liquid-phase refrigerant for cooling the compressor motor, thereby improving the overall energy efficiency of the system.
  • the refrigeration system 200 comprises a main flow path.
  • the main flow path comprises a compressor 210, a condenser 220, a throttling device 230 and an evaporator 240 that are fluidly communicated, with refrigerant circulating through them, wherein the compressor 210 comprises at least a first compression stage and a second compression stage.
  • the compressor 210 may be a high-speed direct-drive compressor in which the motor shaft is directly connected to the compressor impeller without a gearbox.
  • the compressor 210 may include, for example, a compressor inlet 211, a compressor outlet 212, a motor housing 213, a gas supply port 214 between the fluid outlet of the first compression stage and the fluid inlet of the second compression stage, and a compressor bearing chamber 215.
  • the compressor 210 can employ a two-stage centrifugal compressor with oil lubrication.
  • the throttling device 230 may be an expansion valve, such as a mechanical expansion valve or an electronic expansion valve.
  • the refrigeration system also involves oil return, which is intended to direct the lubricant oil in the refrigeration system (usually in the circulating refrigerant) to the compressor bearing chamber 215 for lubricating the compressor bearings.
  • oil return is intended to direct the lubricant oil in the refrigeration system (usually in the circulating refrigerant) to the compressor bearing chamber 215 for lubricating the compressor bearings.
  • the high-speed direct-drive compressor though without the need to use traditional oil cooling devices, needs to maintain an appropriate oil temperature.
  • the refrigeration system 200 further comprises an ejector 250, a separator 260, and an oil tank 270.
  • the ejector 250 is configured to eject oil-containing low-pressure refrigerant from the evaporator 240 by means of high-pressure refrigerant from the condenser 220 and to mix them into a medium-pressure gas-liquid two-phase refrigerant.
  • the separator 260 is arranged downstream of the ejector 250 for separating the gas-liquid two-phase refrigerant from the ejector 250 into a gas-phase refrigerant and a liquid-phase refrigerant.
  • the separator 260 delivers the gas-phase refrigerant separated to the gas supply port 214 between the fluid outlet of the first compression stage and the fluid inlet of the second compression stage in the compressor 210 through the flow path, such that the gas-phase refrigerant mixes with the output gas of the first compression stage and then enters the second compression stage for continued compression.
  • the separator 260 delivers the liquid-phase refrigerant separated to a port on the motor housing 213 of the compressor 210 through the flow path, where the liquid-phase refrigerant is flash evaporated immediately due to a pressure drop. It can be seen that the rotor and stator in the motor housing 213 are cooled by flash evaporation to reduce the temperature.
  • the oil tank 270 is a container arranged downstream of the separator 260 for filtering oil from the liquid-phase refrigerant and delivering the oil to the compressor bearing chamber 215 to lubricate the compressor bearings.
  • the ejector 250 includes a high-pressure fluid inlet 251, a fluid suction inlet 252, and a fluid outlet 253.
  • the high-pressure fluid inlet 251 of the ejector 250 is connected near the bottom of the condenser 220 to receive high-pressure fluid.
  • the fluid suction inlet 252 of the ejector 250 is connected near the internal liquid level of the evaporator 240 to receive low-pressure fluid.
  • the fluid outlet 253 of the ejector 250 is connected to the separator 260 to separate the medium-pressure gas-liquid two-phase refrigerant mixed by the ejector 250 into gas-phase refrigerant and liquid-phase refrigerant.
  • a plurality of ejectors can also be arranged, such as two, three or more.
  • the plurality of ejectors may be arranged in parallel and switched on and off electrically to control the flow of the gas-liquid two-phase refrigerant output, wherein the high-pressure fluid inlets of the plurality of ejectors are connected near the bottom of the condenser and the fluid suction inlets of the plurality of ejectors are connected near the internal liquid level of the evaporator.
  • the plurality of ejectors may be of the same size. Alternatively, each ejector may have a different size to accommodate system requirements for gas supply and motor cooling under different operating conditions.
  • the separator 260 preliminarily filters the oil contained in the gas-liquid two-phase refrigerant.
  • the inlet port of the oil tank 270 is connected to the range from near the internal liquid level of the separator 260 to the bottom of the separator 260.
  • the lubricant oil with a higher purity is delivered to the compressor bearings, e.g., to the compressor bearing chamber 215, for lubricating the compressor bearings.
  • oil with a higher concentration and a more stable state, including its temperature and consistency can be achieved through the two-stage filtrations by the separator and the oil tank.
  • An oil pump 272 may be provided in the oil tank 270 for delivering the fluid from the oil tank 270 to the compressor bearing chamber 215. Therefore, the oil pump 272 is capable of enabling the lubricant oil delivered to the compressor bearing chamber 215 to have an appropriate pressure.
  • the oil tank 270 may include a heater 271, which can be a resistance heater that can be inserted into the wall of the oil tank 270 or directly into the oil tank 270.
  • the heater 271 is used to accelerate the evaporation of part of the liquid-phase refrigerant in the oil tank 270, so that the oil-containing refrigerant to be delivered to lubricate the compressor bearings can have a higher oil concentration.
  • the risk of further lowering the oil temperature due to heat loss caused by refrigerant evaporation will be reduced, thereby ensuring the normal operation of the oil-lubricated bearings and extending service life thereof.
  • the oil-lubricated refrigeration system employs a two-stage filtration method which can greatly improve the purity of the lubricant oil in the oil tank, the turn-on time and power of the heater 271 can be minimized as much as possible, and it is also feasible to remove the heater if necessary.
  • the embodiments of the oil-lubricated refrigeration system according to the present invention can ensure that the purity and temperature of the lubricant oil in the oil tank are more controllable, so that the impact due to fluctuations in the return oil state can be minimized.
  • the oil temperature can be regulated intelligently according to different load conditions, which is conducive to improving the efficiency of the entire refrigeration system.
  • oil is filtered out of the refrigerant by means of the separator and the oil tank, thus ensuring the purity of the lubricant oil in the oil tank.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Power Engineering (AREA)
  • Compressor (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP23176358.2A 2022-05-31 2023-05-31 Kühlsystem Pending EP4286771A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210606847.9A CN117190518A (zh) 2022-05-31 2022-05-31 制冷系统

Publications (1)

Publication Number Publication Date
EP4286771A1 true EP4286771A1 (de) 2023-12-06

Family

ID=86646474

Family Applications (1)

Application Number Title Priority Date Filing Date
EP23176358.2A Pending EP4286771A1 (de) 2022-05-31 2023-05-31 Kühlsystem

Country Status (3)

Country Link
US (1) US20230384008A1 (de)
EP (1) EP4286771A1 (de)
CN (1) CN117190518A (de)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016020783A (ja) * 2014-07-15 2016-02-04 三菱重工業株式会社 ターボ冷凍機の油回収装置
CN114543206A (zh) * 2020-11-25 2022-05-27 开利公司 空调系统及其控制方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016020783A (ja) * 2014-07-15 2016-02-04 三菱重工業株式会社 ターボ冷凍機の油回収装置
CN114543206A (zh) * 2020-11-25 2022-05-27 开利公司 空调系统及其控制方法

Also Published As

Publication number Publication date
US20230384008A1 (en) 2023-11-30
CN117190518A (zh) 2023-12-08

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