US20200103151A1 - A vapour compression system with a suction line liquid separator - Google Patents
A vapour compression system with a suction line liquid separator Download PDFInfo
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- US20200103151A1 US20200103151A1 US16/497,864 US201816497864A US2020103151A1 US 20200103151 A1 US20200103151 A1 US 20200103151A1 US 201816497864 A US201816497864 A US 201816497864A US 2020103151 A1 US2020103151 A1 US 2020103151A1
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- compression system
- vapour compression
- refrigerant
- liquid
- separating device
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- 239000007788 liquid Substances 0.000 title claims abstract description 176
- 230000006835 compression Effects 0.000 title claims abstract description 69
- 238000007906 compression Methods 0.000 title claims abstract description 69
- 239000003507 refrigerant Substances 0.000 claims abstract description 143
- 238000000034 method Methods 0.000 claims abstract description 29
- 230000003247 decreasing effect Effects 0.000 claims description 18
- 238000012544 monitoring process Methods 0.000 claims description 2
- 239000012530 fluid Substances 0.000 description 8
- 238000005057 refrigeration Methods 0.000 description 6
- 238000009825 accumulation Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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Classifications
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- 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
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- 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
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
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- 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
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- F25B41/04—
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- 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
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
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- 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
- F25B5/00—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity
- F25B5/02—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity arranged in parallel
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- 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
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/08—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using ejectors
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- 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
- F25B2341/0012—Ejectors with the cooled primary flow at high pressure
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- 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
- F25B2400/07—Details of compressors or related parts
- F25B2400/075—Details of compressors or related parts with parallel compressors
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- 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
- F25B2400/16—Receivers
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- 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
- F25B2600/00—Control issues
- F25B2600/05—Refrigerant levels
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- 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
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/04—Refrigerant level
Definitions
- the present invention relates to a method for controlling a vapour compression system having a liquid separator arranged in the suction line.
- the method of the invention ensures that the vapour compression system is operated in an energy efficient manner, without risking that liquid refrigerant reaches the compressor.
- a fluid medium such as refrigerant
- a fluid medium such as refrigerant
- compressors e.g. in the form of condensers or gas coolers
- heat absorbing heat exchangers e.g. in the form of evaporators.
- the refrigerant When refrigerant passes through an evaporator arranged in a vapour compression system, the refrigerant is at least partly evaporated while heat exchange takes place with the ambient or with a secondary fluid flow across the evaporator, in such a manner that heat is absorbed by the refrigerant passing through the evaporator.
- the heat transfer between the refrigerant and the ambient or the secondary fluid flow is most efficient along a part of the evaporator which contains liquid refrigerant. Accordingly, it is desirable to operate the vapour compression system in such a manner that liquid refrigerant is present in as large a part of the evaporator as possible, preferably along the entire evaporator.
- EP 2 718 642 B1 discloses a multi-evaporator refrigeration circuit comprising at least a compressor, a condenser or gas cooler, a first throttling valve, a liquid/vapour separator, a pressure limiting valve, a liquid level sensing device, at least one evaporator and a suction receiver.
- a multi-evaporator refrigeration circuit comprising at least a compressor, a condenser or gas cooler, a first throttling valve, a liquid/vapour separator, a pressure limiting valve, a liquid level sensing device, at least one evaporator and a suction receiver.
- at least one ejector comprising a suction port is included in parallel to the first throttling valve.
- the refrigeration system is adapted to drive cold liquid from the suction receiver to the suction port of the ejector.
- a first control valve in the line from the suction receiver to the suction port of the ejector can be opened, based on a maximum level signal generated by the liquid level sensing device, whenever the level of liquid refrigerant in the suction receiver is above a set maximum level.
- the invention provides a method for controlling a vapour compression system, the vapour compression system comprising a compressor unit, a heat rejecting heat exchanger, an ejector, a receiver, at least one expansion device and at least one evaporator arranged in a refrigerant path, the vapour compression system further comprising a liquid separating device arranged in a suction line of the vapour compression system and a liquid level sensor arranged in the liquid separating device, the liquid separating device comprising a gaseous outlet connected to the inlet of the compressor unit and a liquid outlet connected to a secondary inlet of the ejector, the method comprising the steps of:
- vapour compression system should be interpreted to mean any system in which a flow of fluid medium, such as refrigerant, circulates and is alternatingly compressed and expanded, thereby providing either refrigeration or heating of a volume.
- the vapour compression system may be a refrigeration system, an air condition system, a heat pump, etc.
- the vapour compression system comprises a compressor unit comprising one or more compressors, a heat rejecting heat exchanger, an ejector, a receiver, at least one expansion device and at least one evaporator arranged in a refrigerant path.
- Each expansion device is arranged to supply refrigerant to an evaporator.
- the heat rejecting heat exchanger could, e.g., be in the form of a condenser, in which refrigerant is at least partly condensed, or in the form of a gas cooler, in which refrigerant is cooled, but remains in a gaseous or trans-critical state.
- the expansion device(s) could, e.g., be in the form of expansion valve(s).
- the vapour compression system further comprises a liquid separating device arranged in a suction line of the vapour compression system, i.e. in a part of the refrigerant path which interconnects the outlet(s) of the evaporator(s) and the inlet of the compressor unit.
- the liquid separating device comprises a gaseous outlet connected to the inlet of the compressor unit and a liquid outlet connected to a secondary inlet of the ejector.
- the liquid separating device receives refrigerant from the outlet(s) of the evaporator(s) and separates the received refrigerant into a liquid part and a gaseous part.
- the liquid part of the refrigerant is supplied to the secondary inlet of the ejector, and at least part of the gaseous part of the refrigerant may be supplied to the inlet of the compressor unit. It is not ruled out that some or all of the gaseous part of the refrigerant may be supplied to the secondary inlet of the ejector, along with the liquid part of the refrigerant. However, the liquid part of the refrigerant is not supplied to the inlet of the compressor unit. Accordingly, the liquid separating device ensures that any liquid refrigerant which leaves the evaporator(s) and enters the suction line is prevented from reaching the compressor unit.
- a liquid level sensor is arranged in the liquid separating device. Accordingly, the liquid level in the liquid separating device can be measured by means of the liquid level sensor.
- the liquid level in the liquid separating device is monitored by means of the liquid level sensor.
- This provides a measure for the amount of liquid refrigerant which has been accumulated in the liquid separating device, and may further provide an indication regarding whether the liquid level is increasing, decreasing or remaining substantially constant.
- the liquid level is increasing and approaching the gaseous outlet of the liquid separating device, then there is a risk that liquid refrigerant is passed from the liquid separating device towards the inlet of the compressor unit, via the gaseous outlet of the liquid separating device. This should be avoided.
- a control parameter of the vapour compression system is adjusted in order to increase a flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector and/or decrease a flow rate of liquid refrigerant from the evaporator(s) to the liquid separating device.
- steps are taken in order to ensure that the net amount of liquid refrigerant in the liquid separator is reduced, or at least is prevented from increasing further.
- liquid refrigerant is efficiently prevented from reaching the compressor unit, while allowing liquid refrigerant to be present along the entire length of the evaporator(s), thereby allowing the vapour compression system to be operated in an energy efficient manner.
- the step of adjusting a control parameter of the vapour compression system may comprise adjusting a pressure and/or a temperature prevailing in the vapour compression system.
- the pressure could be a refrigerant pressure prevailing at a relevant position of the refrigerant path, such as inside the receiver, at the outlet of the heat rejecting heat exchanger, in the suction line, or in any other relevant part of the refrigerant path.
- the temperature could be a refrigerant temperature prevailing at a relevant position of the refrigerant path, such as at the outlet of the heat rejecting heat exchanger, in the suction line, or in any other relevant part of the refrigerant path.
- the temperature could be an ambient temperature or a temperature of a secondary fluid flow across the heat rejecting heat exchanger.
- the step of adjusting a control parameter of the vapour compression system may comprise reducing a pressure prevailing inside the receiver.
- the pressure difference across the ejector i.e. the pressure difference between the refrigerant leaving the heat rejecting heat exchanger and entering the primary inlet of the ejector and the refrigerant leaving the ejector and entering the receiver.
- This increases the capability of the ejector to drive the secondary refrigerant flow in the ejector, i.e. the flow of refrigerant entering the ejector via the secondary inlet.
- the flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector is increased.
- reducing the pressure prevailing inside the receiver also reduces the pressure difference over which the ejector must lift the secondary refrigerant flow in the ejector, thereby even further improving the capability of the ejector to drive the secondary refrigerant flow.
- the pressure prevailing inside the receiver could, e.g., be decreased by increasing a compressor capacity allocated for compressing refrigerant received from the gaseous outlet of the receiver.
- the step of adjusting a control parameter of the vapour compression system may comprise increasing a pressure of refrigerant leaving the heat rejecting heat exchanger and entering the primary inlet of the ejector. Increasing the pressure of refrigerant leaving the heat rejecting heat exchanger will also increase the pressure difference across the ejector, resulting in an increase in the flow of refrigerant from the liquid separating device to the secondary inlet of the ejector, as described above.
- the pressure of refrigerant leaving the heat rejecting heat exchanger could, e.g., be increased by decreasing an opening degree of the primary inlet of the ejector.
- the pressure of refrigerant leaving the heat rejecting heat exchanger could be increased by decreasing a secondary fluid flow across the heat rejecting heat exchanger, e.g. by reducing a speed of a fan driving a secondary air flow across the heat rejecting heat exchanger or by adjusting a pump driving a secondary liquid flow across the heat rejecting heat exchanger.
- the step of adjusting a control parameter of the vapour compression system may comprise decreasing a pressure prevailing in the suction line of the vapour compression system.
- the pressure prevailing in the suction line is decreased, the pressure of the refrigerant passing through the evaporator(s) is also decreased.
- the dew point if the refrigerant is also decreased, causing a larger portion of the refrigerant to evaporate while passing through the evaporator(s). Accordingly, the amount of liquid refrigerant passing through the evaporator(s) is decreased.
- the step of adjusting a control parameter of the vapour compression system may comprise increasing a temperature of refrigerant leaving the heat rejecting heat exchanger and entering the primary inlet of the ejector.
- the temperature of refrigerant leaving the heat rejecting heat exchanger is increased, the gas-to-liquid ratio of the refrigerant at the outlet of the ejector is increased. This increases the total flow rate of refrigerant in a refrigerant loop including the compressor unit, the heat rejecting heat exchanger, the ejector, the receiver and a bypass valve arranged between the gaseous outlet of the receiver and the inlet of the compressor unit.
- This increases the flow rate of refrigerant through the ejector, from the primary inlet to the outlet, thereby improving the capability of the ejector to drive the secondary refrigerant flow in the ejector, i.e. the flow of refrigerant entering the ejector via the secondary inlet. Accordingly, the flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector is increased.
- the temperature of refrigerant leaving the heat rejecting heat exchanger could, e.g., be increased by decreasing a secondary fluid flow across the heat rejecting heat exchanger, e.g. by reducing a speed of a fan driving a secondary air flow across the heat rejecting heat exchanger or by adjusting a pump driving a secondary liquid flow across the heat rejecting heat exchanger.
- the step of adjusting a control parameter of the vapour compression system may comprise preventing at least some of the evaporator(s) from being operated in a flooded state.
- a control parameter of the vapour compression system may comprise preventing at least some of the evaporator(s) from being operated in a flooded state.
- the evaporator(s) may, e.g., be prevented from operating in a flooded state by increasing a setpoint value or a lower limit for the superheat of refrigerant leaving the evaporator(s), and subsequently controlling the refrigerant supply to the evaporator(s) in accordance with the increased setpoint value or lower limit.
- the superheat of refrigerant leaving an evaporator is the temperature difference between the temperature of refrigerant leaving the evaporator and the dew point of the refrigerant leaving the evaporator.
- a high superheat value indicates that all of the liquid refrigerant supplied to the evaporator is evaporated well before it reaches the outlet of the evaporator. As described above, this results in a relatively poor heat transfer in the evaporator.
- only gaseous refrigerant passes through the evaporator.
- zero superheat indicates that liquid refrigerant is present along the entire length of the evaporator, i.e. that the evaporator is operated in a flooded state.
- selecting a positive setpoint for the superheat value will prevent the evaporator from being operated in a flooded state.
- the evaporator(s) may be prevented from being operated in a flooded state by reducing a maximum allowable opening degree of the expansion device(s). This will limit the refrigerant supply to the evaporator(s), thereby reducing the amount of liquid refrigerant passing through the evaporator(s), entering the suction line and being supplied to the liquid separating device.
- FIG. 1 is a diagrammatic view of a vapour compression system being controlled in accordance with a method according to a first embodiment of the invention
- FIG. 2 is a diagrammatic view of a vapour compression system being controlled in accordance with a method according to a second embodiment of the invention.
- FIG. 3 is a diagrammatic view of a vapour compression system being controlled in accordance with a method according to a third embodiment of the invention.
- FIG. 1 is a diagrammatic view of a vapour compression system 1 being controlled in accordance with a method according to a first embodiment of the invention.
- the vapour compression system 1 comprises a compressor unit 2 comprising a number of compressors 3 , 4 , three of which are shown, a heat rejecting heat exchanger 5 , an ejector 6 , a receiver 7 , an expansion device 8 , in the form of an expansion valve, an evaporator 9 , and a liquid separating device 10 , arranged in a refrigerant path.
- Two of the shown compressors 3 are connected to a gaseous outlet 11 of the liquid separating device 10 . Accordingly, gaseous refrigerant leaving the evaporator 9 can be supplied to these compressors 3 , via the liquid separating device 10 .
- the third compressor 4 is connected to a gaseous outlet 12 of the receiver 7 . Accordingly, gaseous refrigerant can be supplied directly from the receiver 7 to this compressor 4 .
- Refrigerant flowing in the refrigerant path is compressed by the compressors 3 , 4 of the compressor unit 2 .
- the compressed refrigerant is supplied to the heat rejecting heat exchanger 5 , where heat exchange takes place in such a manner that heat is rejected from the refrigerant.
- the refrigerant leaving the heat rejecting heat exchanger 5 is supplied to a primary inlet 13 of the ejector 6 , before being supplied to the receiver 7 .
- the refrigerant When passing through the ejector 6 the refrigerant undergoes expansion. Thereby the pressure of the refrigerant is reduced, and the refrigerant being supplied to the receiver 7 is in a mixed liquid and gaseous state.
- the refrigerant In the receiver 7 the refrigerant is separated into a liquid part and a gaseous part.
- the liquid part of the refrigerant is supplied to the evaporator 9 , via a liquid outlet 14 of the receiver 7 and the expansion device 8 .
- the liquid part of the refrigerant In the evaporator 9 , the liquid part of the refrigerant is at least partly evaporated, while heat exchange takes place in such a manner that heat is absorbed by the refrigerant.
- the evaporator 9 may be operated in a flooded state, i.e. in such a manner that liquid refrigerant is present along the entire length of the evaporator 9 . Accordingly, some of the refrigerant passing through the evaporator 9 and entering the suction line may be in a liquid state.
- the refrigerant leaving the evaporator 9 is received in the liquid separating device 10 , where the refrigerant is separated into a liquid part and a gaseous part.
- the liquid part of the refrigerant is supplied to a secondary inlet 15 of the ejector 6 , via a liquid outlet 16 of the liquid separating device 10 .
- At least some of the gaseous refrigerant may be supplied to the compressors 3 of the compressor unit 2 via the gaseous outlet 11 of the liquid separating device 10 .
- it is not ruled out that at least some of the gaseous refrigerant is supplied to the secondary inlet 15 of the ejector 6 , via the liquid outlet 16 of the liquid separating device 10 .
- the liquid separating device 10 ensures that any liquid refrigerant which passes through the evaporator 9 is prevented from reaching the compressors 3 , 4 of the compressor unit 2 . Instead such liquid refrigerant is supplied to the secondary inlet 15 of the ejector 6 .
- the gaseous part of the refrigerant in the receiver 7 may be supplied to the compressor 4 . Furthermore, some of the gaseous refrigerant in the receiver 7 may be supplied to compressors 3 , via a bypass valve 17 . Opening the bypass valve 17 increases the compressor capacity being available for compressing refrigerant received from the gaseous outlet 12 of the receiver 7 .
- a liquid level sensor 18 is arranged in the liquid separating device 10 . Thereby the liquid level in the liquid separating device 10 can be monitored by means of the liquid level sensor 18 .
- a liquid level in the liquid separating device 10 is monitored by means of the liquid level sensor 18 , and the monitored liquid level is compared to a predefined threshold level.
- a control parameter of the vapour compression system 1 is adjusted in order to increase a flow rate of refrigerant from the liquid separating device 10 to the secondary inlet 15 of the ejector 6 and/or decrease a flow rate of liquid refrigerant from the evaporator 9 to the liquid separating device 10 .
- the flow rate of refrigerant from the liquid separating device 10 to the secondary inlet 15 of the ejector 6 could, e.g., be increased by decreasing a pressure prevailing inside the receiver 7 , by increasing a pressure of refrigerant leaving the heat rejecting heat exchanger 5 and entering the primary inlet 13 of the ejector 6 , and/or by increasing a temperature of refrigerant leaving the heat rejecting heat exchanger 5 and entering the primary inlet 13 of the ejector 6 . This has been described in detail above.
- the flow rate of liquid refrigerant from the evaporator 9 to the liquid separating device 10 could, e.g., be decreased by preventing the evaporator 9 from operating in a flooded state or by decreasing a pressure prevailing in the suction line. This has been described in detail above.
- FIG. 2 is a diagrammatic view of a vapour compression system 1 being controlled in accordance with a method according to a second embodiment of the invention.
- the vapour compression system 1 of FIG. 2 is very similar to the vapour compression system 1 of FIG. 1 , and it will therefore not be described in detail here.
- vapour compression system 1 of FIG. 2 only two compressors 3 are shown in the compressor unit 2 . Both of the compressors 3 are connected to the gaseous outlet 11 of the liquid separating device 10 . Accordingly, gaseous refrigerant from the receiver 7 can only be supplied to the compressor unit 2 via the bypass valve 17 .
- FIG. 3 is a diagrammatic view of a vapour compression system 1 being controlled in accordance with a method according to a third embodiment of the invention.
- the vapour compression system 1 of FIG. 3 is very similar to the vapour compression systems 1 of FIGS. 1 and 2 , and it will therefore not be described in detail here.
- one compressor 3 is shown as being connected to the gaseous outlet 11 of the liquid separating device 10 and one compressor 4 is shown as being connected to the gaseous outlet 12 of the receiver 7 .
- a third compressor 19 is shown as being provided with a three way valve 20 which allows the compressor 19 to be selectively connected to the gaseous outlet 11 of the liquid separating device 10 or to the gaseous outlet 12 of the receiver 7 .
- ‘main compressor capacity’ i.e. when the compressor 19 is connected to the gaseous outlet 11 of the liquid separating device 10
- ‘receiver compressor capacity’ i.e.
- the vapour compression system 1 of FIG. 3 comprises three expansion devices 8 a , 8 b , 8 c and three evaporators 9 a , 9 b , 9 c , arranged fluidly in parallel in the refrigerant path.
- Each of the expansion devices 8 a , 8 b , 8 c is arranged to control a flow of refrigerant to one of the evaporators 9 a , 9 b , 9 c.
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Abstract
Description
- This application is a National Stage application of International Patent Application No. PCT/EP2018/057515, filed on Mar. 23, 2018, which claims priority to Danish Patent Application No. PA201700214 filed Mar. 28, 2017, each of which is hereby incorporated by reference in its entirety.
- The present invention relates to a method for controlling a vapour compression system having a liquid separator arranged in the suction line. The method of the invention ensures that the vapour compression system is operated in an energy efficient manner, without risking that liquid refrigerant reaches the compressor.
- In a vapour compression system, such as a refrigeration system, an air condition system, a heat pump, etc., a fluid medium, such as refrigerant, is alternatingly compressed by means of one or more compressors and expanded by means of one or more expansion devices, and heat exchange between the fluid medium and the ambient takes place in one or more heat rejecting heat exchangers, e.g. in the form of condensers or gas coolers, and in one or more heat absorbing heat exchangers, e.g. in the form of evaporators.
- When refrigerant passes through an evaporator arranged in a vapour compression system, the refrigerant is at least partly evaporated while heat exchange takes place with the ambient or with a secondary fluid flow across the evaporator, in such a manner that heat is absorbed by the refrigerant passing through the evaporator. The heat transfer between the refrigerant and the ambient or the secondary fluid flow is most efficient along a part of the evaporator which contains liquid refrigerant. Accordingly, it is desirable to operate the vapour compression system in such a manner that liquid refrigerant is present in as large a part of the evaporator as possible, preferably along the entire evaporator.
- However, if liquid refrigerant reaches the compressor unit, there is a risk that the compressor(s) of the compressor unit is/are damaged. In order to avoid this, it is necessary to either operate the vapour compression system in such a manner that liquid refrigerant is not allowed to pass through the evaporator, or to ensure that any liquid refrigerant which passes through the evaporator is removed from the suction line, and is thereby prevented from reaching the compressor unit. To this end a liquid separating device is sometimes arranged in the suction line.
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EP 2 718 642 B1 discloses a multi-evaporator refrigeration circuit comprising at least a compressor, a condenser or gas cooler, a first throttling valve, a liquid/vapour separator, a pressure limiting valve, a liquid level sensing device, at least one evaporator and a suction receiver. In the refrigeration circuit at least one ejector comprising a suction port is included in parallel to the first throttling valve. The refrigeration system is adapted to drive cold liquid from the suction receiver to the suction port of the ejector. A first control valve in the line from the suction receiver to the suction port of the ejector can be opened, based on a maximum level signal generated by the liquid level sensing device, whenever the level of liquid refrigerant in the suction receiver is above a set maximum level. - It is an object of embodiments of the invention to provide a method for controlling a vapour compression system in an energy efficient manner, without risking that liquid refrigerant reaches the compressor unit.
- The invention provides a method for controlling a vapour compression system, the vapour compression system comprising a compressor unit, a heat rejecting heat exchanger, an ejector, a receiver, at least one expansion device and at least one evaporator arranged in a refrigerant path, the vapour compression system further comprising a liquid separating device arranged in a suction line of the vapour compression system and a liquid level sensor arranged in the liquid separating device, the liquid separating device comprising a gaseous outlet connected to the inlet of the compressor unit and a liquid outlet connected to a secondary inlet of the ejector, the method comprising the steps of:
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- monitoring a liquid level in the liquid separating device by means of the liquid level sensor, and
- in the case that the liquid level in the liquid separating device is above a predefined threshold level, adjusting a control parameter of the vapour compression system in order to increase a flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector and/or decrease a flow rate of liquid refrigerant from the evaporator(s) to the liquid separating device.
- The method according to the invention is for controlling a vapour compression system. In the present context the term ‘vapour compression system’ should be interpreted to mean any system in which a flow of fluid medium, such as refrigerant, circulates and is alternatingly compressed and expanded, thereby providing either refrigeration or heating of a volume. Thus, the vapour compression system may be a refrigeration system, an air condition system, a heat pump, etc.
- The vapour compression system comprises a compressor unit comprising one or more compressors, a heat rejecting heat exchanger, an ejector, a receiver, at least one expansion device and at least one evaporator arranged in a refrigerant path. Each expansion device is arranged to supply refrigerant to an evaporator. The heat rejecting heat exchanger could, e.g., be in the form of a condenser, in which refrigerant is at least partly condensed, or in the form of a gas cooler, in which refrigerant is cooled, but remains in a gaseous or trans-critical state. The expansion device(s) could, e.g., be in the form of expansion valve(s).
- The vapour compression system further comprises a liquid separating device arranged in a suction line of the vapour compression system, i.e. in a part of the refrigerant path which interconnects the outlet(s) of the evaporator(s) and the inlet of the compressor unit. The liquid separating device comprises a gaseous outlet connected to the inlet of the compressor unit and a liquid outlet connected to a secondary inlet of the ejector. Thus, the liquid separating device receives refrigerant from the outlet(s) of the evaporator(s) and separates the received refrigerant into a liquid part and a gaseous part. The liquid part of the refrigerant is supplied to the secondary inlet of the ejector, and at least part of the gaseous part of the refrigerant may be supplied to the inlet of the compressor unit. It is not ruled out that some or all of the gaseous part of the refrigerant may be supplied to the secondary inlet of the ejector, along with the liquid part of the refrigerant. However, the liquid part of the refrigerant is not supplied to the inlet of the compressor unit. Accordingly, the liquid separating device ensures that any liquid refrigerant which leaves the evaporator(s) and enters the suction line is prevented from reaching the compressor unit.
- A liquid level sensor is arranged in the liquid separating device. Accordingly, the liquid level in the liquid separating device can be measured by means of the liquid level sensor.
- Thus, according to the method of the invention, the liquid level in the liquid separating device is monitored by means of the liquid level sensor. This provides a measure for the amount of liquid refrigerant which has been accumulated in the liquid separating device, and may further provide an indication regarding whether the liquid level is increasing, decreasing or remaining substantially constant. In the case that the liquid level is increasing and approaching the gaseous outlet of the liquid separating device, then there is a risk that liquid refrigerant is passed from the liquid separating device towards the inlet of the compressor unit, via the gaseous outlet of the liquid separating device. This should be avoided.
- Accordingly, in the case that the liquid level in the liquid separating device is above a predefined threshold level, a control parameter of the vapour compression system is adjusted in order to increase a flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector and/or decrease a flow rate of liquid refrigerant from the evaporator(s) to the liquid separating device.
- Increasing the flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector will cause more liquid refrigerant to be transferred from the liquid separating device to the secondary inlet of the ejector, thereby reducing the liquid level in the liquid separating device.
- Decreasing a flow rate of liquid refrigerant from the evaporator(s) to the liquid separating device will cause less liquid refrigerant to be transferred from the evaporator(s) to the liquid separating device, and this may allow the current flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector to remove enough liquid refrigerant from the liquid separating device to reduce the liquid level in the liquid separating device.
- Thus, according to the invention, in the case that it is detected that the liquid level in the liquid separating device is above the predefined threshold level, steps are taken in order to ensure that the net amount of liquid refrigerant in the liquid separator is reduced, or at least is prevented from increasing further. Thereby liquid refrigerant is efficiently prevented from reaching the compressor unit, while allowing liquid refrigerant to be present along the entire length of the evaporator(s), thereby allowing the vapour compression system to be operated in an energy efficient manner.
- The step of adjusting a control parameter of the vapour compression system may comprise adjusting a pressure and/or a temperature prevailing in the vapour compression system. The pressure could be a refrigerant pressure prevailing at a relevant position of the refrigerant path, such as inside the receiver, at the outlet of the heat rejecting heat exchanger, in the suction line, or in any other relevant part of the refrigerant path. Similarly, the temperature could be a refrigerant temperature prevailing at a relevant position of the refrigerant path, such as at the outlet of the heat rejecting heat exchanger, in the suction line, or in any other relevant part of the refrigerant path. Alternatively, the temperature could be an ambient temperature or a temperature of a secondary fluid flow across the heat rejecting heat exchanger.
- Thus, the step of adjusting a control parameter of the vapour compression system may comprise reducing a pressure prevailing inside the receiver. When the pressure prevailing inside the receiver is reduced, the pressure difference across the ejector, i.e. the pressure difference between the refrigerant leaving the heat rejecting heat exchanger and entering the primary inlet of the ejector and the refrigerant leaving the ejector and entering the receiver, is increased. This increases the capability of the ejector to drive the secondary refrigerant flow in the ejector, i.e. the flow of refrigerant entering the ejector via the secondary inlet. Thereby the flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector is increased. Furthermore, reducing the pressure prevailing inside the receiver also reduces the pressure difference over which the ejector must lift the secondary refrigerant flow in the ejector, thereby even further improving the capability of the ejector to drive the secondary refrigerant flow.
- The pressure prevailing inside the receiver could, e.g., be decreased by increasing a compressor capacity allocated for compressing refrigerant received from the gaseous outlet of the receiver.
- Alternatively or additionally, the step of adjusting a control parameter of the vapour compression system may comprise increasing a pressure of refrigerant leaving the heat rejecting heat exchanger and entering the primary inlet of the ejector. Increasing the pressure of refrigerant leaving the heat rejecting heat exchanger will also increase the pressure difference across the ejector, resulting in an increase in the flow of refrigerant from the liquid separating device to the secondary inlet of the ejector, as described above.
- The pressure of refrigerant leaving the heat rejecting heat exchanger could, e.g., be increased by decreasing an opening degree of the primary inlet of the ejector. Alternatively or additionally, the pressure of refrigerant leaving the heat rejecting heat exchanger could be increased by decreasing a secondary fluid flow across the heat rejecting heat exchanger, e.g. by reducing a speed of a fan driving a secondary air flow across the heat rejecting heat exchanger or by adjusting a pump driving a secondary liquid flow across the heat rejecting heat exchanger.
- Alternatively or additionally, the step of adjusting a control parameter of the vapour compression system may comprise decreasing a pressure prevailing in the suction line of the vapour compression system. When the pressure prevailing in the suction line is decreased, the pressure of the refrigerant passing through the evaporator(s) is also decreased. Thereby the dew point if the refrigerant is also decreased, causing a larger portion of the refrigerant to evaporate while passing through the evaporator(s). Accordingly, the amount of liquid refrigerant passing through the evaporator(s) is decreased.
- Alternatively or additionally, the step of adjusting a control parameter of the vapour compression system may comprise increasing a temperature of refrigerant leaving the heat rejecting heat exchanger and entering the primary inlet of the ejector. When the temperature of refrigerant leaving the heat rejecting heat exchanger is increased, the gas-to-liquid ratio of the refrigerant at the outlet of the ejector is increased. This increases the total flow rate of refrigerant in a refrigerant loop including the compressor unit, the heat rejecting heat exchanger, the ejector, the receiver and a bypass valve arranged between the gaseous outlet of the receiver and the inlet of the compressor unit. This increases the flow rate of refrigerant through the ejector, from the primary inlet to the outlet, thereby improving the capability of the ejector to drive the secondary refrigerant flow in the ejector, i.e. the flow of refrigerant entering the ejector via the secondary inlet. Accordingly, the flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector is increased.
- The temperature of refrigerant leaving the heat rejecting heat exchanger could, e.g., be increased by decreasing a secondary fluid flow across the heat rejecting heat exchanger, e.g. by reducing a speed of a fan driving a secondary air flow across the heat rejecting heat exchanger or by adjusting a pump driving a secondary liquid flow across the heat rejecting heat exchanger.
- The step of adjusting a control parameter of the vapour compression system may comprise preventing at least some of the evaporator(s) from being operated in a flooded state. When at least some of the evaporator(s) are prevented from being operated in a flooded state, it must be expected that the total amount of liquid refrigerant being supplied to the suction line, and thereby to the liquid separating device, from the evaporator(s) is reduced. This is in particular the case when the evaporator(s) was/were previously operated in a flooded state. For instance, all of the evaporators may be prevented from being operated in a flooded state. In this case, liquid refrigerant is no longer allowed to pass through any of the evaporators, i.e. no liquid refrigerant enters the suction line and thereby the liquid separating device, and the amount of liquid refrigerant in the liquid separating device is not increased, regardless of the flow rate of refrigerant from the liquid separating device to the secondary inlet of the ejector.
- The evaporator(s) may, e.g., be prevented from operating in a flooded state by increasing a setpoint value or a lower limit for the superheat of refrigerant leaving the evaporator(s), and subsequently controlling the refrigerant supply to the evaporator(s) in accordance with the increased setpoint value or lower limit.
- The superheat of refrigerant leaving an evaporator is the temperature difference between the temperature of refrigerant leaving the evaporator and the dew point of the refrigerant leaving the evaporator. Thus, a high superheat value indicates that all of the liquid refrigerant supplied to the evaporator is evaporated well before it reaches the outlet of the evaporator. As described above, this results in a relatively poor heat transfer in the evaporator. However, only gaseous refrigerant passes through the evaporator. Similarly, zero superheat indicates that liquid refrigerant is present along the entire length of the evaporator, i.e. that the evaporator is operated in a flooded state. Thus, selecting a positive setpoint for the superheat value will prevent the evaporator from being operated in a flooded state.
- As an alternative, the evaporator(s) may be prevented from being operated in a flooded state by reducing a maximum allowable opening degree of the expansion device(s). This will limit the refrigerant supply to the evaporator(s), thereby reducing the amount of liquid refrigerant passing through the evaporator(s), entering the suction line and being supplied to the liquid separating device.
- The invention will now be described with reference to the accompanying drawings in which
-
FIG. 1 is a diagrammatic view of a vapour compression system being controlled in accordance with a method according to a first embodiment of the invention, -
FIG. 2 is a diagrammatic view of a vapour compression system being controlled in accordance with a method according to a second embodiment of the invention, and -
FIG. 3 is a diagrammatic view of a vapour compression system being controlled in accordance with a method according to a third embodiment of the invention. -
FIG. 1 is a diagrammatic view of avapour compression system 1 being controlled in accordance with a method according to a first embodiment of the invention. Thevapour compression system 1 comprises acompressor unit 2 comprising a number ofcompressors 3, 4, three of which are shown, a heat rejectingheat exchanger 5, anejector 6, areceiver 7, anexpansion device 8, in the form of an expansion valve, an evaporator 9, and aliquid separating device 10, arranged in a refrigerant path. - Two of the shown
compressors 3 are connected to agaseous outlet 11 of theliquid separating device 10. Accordingly, gaseous refrigerant leaving the evaporator 9 can be supplied to thesecompressors 3, via theliquid separating device 10. The third compressor 4 is connected to agaseous outlet 12 of thereceiver 7. Accordingly, gaseous refrigerant can be supplied directly from thereceiver 7 to this compressor 4. - Refrigerant flowing in the refrigerant path is compressed by the
compressors 3, 4 of thecompressor unit 2. The compressed refrigerant is supplied to the heat rejectingheat exchanger 5, where heat exchange takes place in such a manner that heat is rejected from the refrigerant. - The refrigerant leaving the heat rejecting
heat exchanger 5 is supplied to aprimary inlet 13 of theejector 6, before being supplied to thereceiver 7. - When passing through the
ejector 6 the refrigerant undergoes expansion. Thereby the pressure of the refrigerant is reduced, and the refrigerant being supplied to thereceiver 7 is in a mixed liquid and gaseous state. - In the
receiver 7 the refrigerant is separated into a liquid part and a gaseous part. The liquid part of the refrigerant is supplied to the evaporator 9, via aliquid outlet 14 of thereceiver 7 and theexpansion device 8. In the evaporator 9, the liquid part of the refrigerant is at least partly evaporated, while heat exchange takes place in such a manner that heat is absorbed by the refrigerant. - The evaporator 9 may be operated in a flooded state, i.e. in such a manner that liquid refrigerant is present along the entire length of the evaporator 9. Accordingly, some of the refrigerant passing through the evaporator 9 and entering the suction line may be in a liquid state.
- The refrigerant leaving the evaporator 9 is received in the
liquid separating device 10, where the refrigerant is separated into a liquid part and a gaseous part. The liquid part of the refrigerant is supplied to asecondary inlet 15 of theejector 6, via aliquid outlet 16 of theliquid separating device 10. At least some of the gaseous refrigerant may be supplied to thecompressors 3 of thecompressor unit 2 via thegaseous outlet 11 of theliquid separating device 10. However, it is not ruled out that at least some of the gaseous refrigerant is supplied to thesecondary inlet 15 of theejector 6, via theliquid outlet 16 of theliquid separating device 10. - Accordingly, the
liquid separating device 10 ensures that any liquid refrigerant which passes through the evaporator 9 is prevented from reaching thecompressors 3, 4 of thecompressor unit 2. Instead such liquid refrigerant is supplied to thesecondary inlet 15 of theejector 6. - The gaseous part of the refrigerant in the
receiver 7 may be supplied to the compressor 4. Furthermore, some of the gaseous refrigerant in thereceiver 7 may be supplied tocompressors 3, via abypass valve 17. Opening thebypass valve 17 increases the compressor capacity being available for compressing refrigerant received from thegaseous outlet 12 of thereceiver 7. - A
liquid level sensor 18 is arranged in theliquid separating device 10. Thereby the liquid level in theliquid separating device 10 can be monitored by means of theliquid level sensor 18. - Thus, according to the method of the invention, a liquid level in the
liquid separating device 10 is monitored by means of theliquid level sensor 18, and the monitored liquid level is compared to a predefined threshold level. - When the liquid level in the
liquid separating device 10 is above the predefined threshold level, this is an indication that the liquid level in theliquid separating device 10 is approaching thegaseous outlet 11 of theliquid separating device 10. This may eventually result in liquid refrigerant flowing towards thecompressor unit 2, via thegaseous outlet 11 of theliquid separating device 10. This is undesirable, since it may cause damage to thecompressors 3, 4. - Therefore, in the case that the liquid level in the
liquid separating device 10 is above the predefined threshold level, a control parameter of thevapour compression system 1 is adjusted in order to increase a flow rate of refrigerant from theliquid separating device 10 to thesecondary inlet 15 of theejector 6 and/or decrease a flow rate of liquid refrigerant from the evaporator 9 to theliquid separating device 10. Thereby it is ensured that the flow rate of refrigerant from theliquid separating device 10 to thesecondary inlet 15 of theejector 6 is sufficient to remove the liquid refrigerant produced by the evaporator 9, and accumulation of liquid refrigerant in theliquid separating device 10 is avoided. - The flow rate of refrigerant from the
liquid separating device 10 to thesecondary inlet 15 of theejector 6 could, e.g., be increased by decreasing a pressure prevailing inside thereceiver 7, by increasing a pressure of refrigerant leaving the heat rejectingheat exchanger 5 and entering theprimary inlet 13 of theejector 6, and/or by increasing a temperature of refrigerant leaving the heat rejectingheat exchanger 5 and entering theprimary inlet 13 of theejector 6. This has been described in detail above. - The flow rate of liquid refrigerant from the evaporator 9 to the
liquid separating device 10 could, e.g., be decreased by preventing the evaporator 9 from operating in a flooded state or by decreasing a pressure prevailing in the suction line. This has been described in detail above. -
FIG. 2 is a diagrammatic view of avapour compression system 1 being controlled in accordance with a method according to a second embodiment of the invention. Thevapour compression system 1 ofFIG. 2 is very similar to thevapour compression system 1 ofFIG. 1 , and it will therefore not be described in detail here. - In the
vapour compression system 1 ofFIG. 2 , only twocompressors 3 are shown in thecompressor unit 2. Both of thecompressors 3 are connected to thegaseous outlet 11 of theliquid separating device 10. Accordingly, gaseous refrigerant from thereceiver 7 can only be supplied to thecompressor unit 2 via thebypass valve 17. -
FIG. 3 is a diagrammatic view of avapour compression system 1 being controlled in accordance with a method according to a third embodiment of the invention. Thevapour compression system 1 ofFIG. 3 is very similar to thevapour compression systems 1 ofFIGS. 1 and 2 , and it will therefore not be described in detail here. - In the
compressor unit 2 of thevapour compression system 1 ofFIG. 3 , onecompressor 3 is shown as being connected to thegaseous outlet 11 of theliquid separating device 10 and one compressor 4 is shown as being connected to thegaseous outlet 12 of thereceiver 7. Athird compressor 19 is shown as being provided with a threeway valve 20 which allows thecompressor 19 to be selectively connected to thegaseous outlet 11 of theliquid separating device 10 or to thegaseous outlet 12 of thereceiver 7. Thereby some of the compressor capacity of thecompressor unit 2 can be shifted between ‘main compressor capacity’, i.e. when thecompressor 19 is connected to thegaseous outlet 11 of theliquid separating device 10, and ‘receiver compressor capacity’, i.e. when thecompressor 19 is connected to thegaseous outlet 12 of thereceiver 7. Thereby it is possible to adjust the pressure prevailing inside thereceiver 7, and thereby the flow rate of refrigerant from theliquid separating device 10 to thesecondary inlet 15 of theejector 6, by operating the threeway valve 20, thereby increasing or decreasing the amount of compressor capacity being available for compressing refrigerant received from thegaseous outlet 12 of thereceiver 7. - Furthermore, the
vapour compression system 1 ofFIG. 3 comprises threeexpansion devices evaporators expansion devices evaporators - While the present disclosure has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure.
Claims (14)
Applications Claiming Priority (3)
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DKPA201700214 | 2017-03-28 | ||
DKPA201700214 | 2017-03-28 | ||
PCT/EP2018/057515 WO2018177956A1 (en) | 2017-03-28 | 2018-03-23 | A vapour compression system with a suction line liquid separator |
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US20200103151A1 true US20200103151A1 (en) | 2020-04-02 |
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US16/497,864 Pending US20200103151A1 (en) | 2017-03-28 | 2018-03-23 | A vapour compression system with a suction line liquid separator |
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US (1) | US20200103151A1 (en) |
EP (1) | EP3601907B1 (en) |
CN (1) | CN110573810A (en) |
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WO (1) | WO2018177956A1 (en) |
Cited By (2)
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US20210348810A1 (en) * | 2020-05-06 | 2021-11-11 | Carrier Corporation | Ejector refrigeration circuit |
US11320170B2 (en) * | 2017-10-16 | 2022-05-03 | Denso Corporation | Heat pump cycle |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US11353244B2 (en) | 2020-07-27 | 2022-06-07 | Heatcraft Refrigeration Products Llc | Cooling system with flexible evaporating temperature |
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US1836318A (en) * | 1926-07-26 | 1931-12-15 | Norman H Gay | Refrigerating system |
US3600904A (en) | 1969-05-27 | 1971-08-24 | Emerson Electric Co | Control for refrigeration system |
US3788394A (en) * | 1972-06-01 | 1974-01-29 | Motor Coach Ind Inc | Reverse balance flow valve assembly for refrigerant systems |
JPS6268115A (en) | 1985-09-20 | 1987-03-28 | Sanden Corp | Control device for air conditioner for motor vehicle |
JP3956793B2 (en) * | 2002-07-25 | 2007-08-08 | 株式会社デンソー | Ejector cycle |
EP1974171B1 (en) * | 2006-09-29 | 2014-07-23 | Carrier Corporation | Refrigerant vapor compression system with flash tank receiver |
US8539786B2 (en) * | 2007-10-08 | 2013-09-24 | Emerson Climate Technologies, Inc. | System and method for monitoring overheat of a compressor |
JP2010151424A (en) * | 2008-12-26 | 2010-07-08 | Daikin Ind Ltd | Refrigerating device |
US9217590B2 (en) * | 2011-01-04 | 2015-12-22 | United Technologies Corporation | Ejector cycle |
DK2718642T3 (en) * | 2011-06-06 | 2016-12-19 | Huurre Group Oy | Multi-evaporator cooling circuits |
CN105008826A (en) * | 2012-12-27 | 2015-10-28 | 冷王公司 | Method of reducing liquid flooding in a transport refrigeration unit |
JP5751355B1 (en) | 2014-01-31 | 2015-07-22 | ダイキン工業株式会社 | Refrigeration equipment |
MX2017002730A (en) * | 2014-09-05 | 2017-09-01 | Danfoss As | A method for controlling a variable capacity ejector unit. |
EP3023713A1 (en) * | 2014-11-19 | 2016-05-25 | Danfoss A/S | A method for controlling a vapour compression system with an ejector |
CN107532827B (en) * | 2015-05-12 | 2021-06-08 | 开利公司 | Ejector refrigeration circuit |
AU2016101310A4 (en) | 2016-05-16 | 2016-08-25 | Epta S.P.A. | Refrigeration plant with multiple evaporation levels and method of managing such a plant |
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2018
- 2018-03-23 US US16/497,864 patent/US20200103151A1/en active Pending
- 2018-03-23 CN CN201880027276.5A patent/CN110573810A/en active Pending
- 2018-03-23 PL PL18715561.9T patent/PL3601907T3/en unknown
- 2018-03-23 EP EP18715561.9A patent/EP3601907B1/en active Active
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US11320170B2 (en) * | 2017-10-16 | 2022-05-03 | Denso Corporation | Heat pump cycle |
US20210348810A1 (en) * | 2020-05-06 | 2021-11-11 | Carrier Corporation | Ejector refrigeration circuit |
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WO2018177956A1 (en) | 2018-10-04 |
EP3601907A1 (en) | 2020-02-05 |
CN110573810A (en) | 2019-12-13 |
EP3601907B1 (en) | 2022-04-20 |
PL3601907T3 (en) | 2022-08-16 |
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