US20210247107A1 - Method and system for cooling a motor during motor startup - Google Patents
Method and system for cooling a motor during motor startup Download PDFInfo
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- US20210247107A1 US20210247107A1 US16/973,567 US201916973567A US2021247107A1 US 20210247107 A1 US20210247107 A1 US 20210247107A1 US 201916973567 A US201916973567 A US 201916973567A US 2021247107 A1 US2021247107 A1 US 2021247107A1
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- liquid coolant
- condenser
- motor
- compressor
- reservoir
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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
- F25B1/04—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
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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
- F25B31/00—Compressor arrangements
- F25B31/002—Lubrication
- F25B31/004—Lubrication oil recirculating arrangements
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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
- F25B31/00—Compressor arrangements
- F25B31/006—Cooling of compressor or motor
- F25B31/008—Cooling of compressor or motor by injecting a liquid
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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
- F25B31/00—Compressor arrangements
- F25B31/02—Compressor arrangements of motor-compressor units
- F25B31/026—Compressor arrangements of motor-compressor units with compressor of rotary type
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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
- 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
- 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
- F25B49/022—Compressor control arrangements
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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
- F25B49/025—Motor control arrangements
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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
- F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
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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
- F25B2500/00—Problems to be solved
- F25B2500/16—Lubrication
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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
- F25B2500/00—Problems to be solved
- F25B2500/26—Problems to be solved characterised by the startup of the refrigeration cycle
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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
- F25B2600/23—Time delays
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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
- F25B31/00—Compressor arrangements
- F25B31/002—Lubrication
Definitions
- the present disclosure relates generally to compressor motor cooling and lubrication, and more specifically to compressor motor cooling and lubrication during a startup sequence.
- HVAC heating, ventilation and cooling
- GWP Global Warming Potential
- High-efficiency compressors such as high speed centrifugal compressors
- High speed motors require that the motor bearings be cooled and lubricated via a cooling system in order to keep the motor system below a limitation temperature and prevent the bearings from overheating.
- Traditional air cooling of such systems can be inadequate for a high speed motor, and independent oil based liquid cooling leads to complex systems and increases costs.
- a heating ventilation and air conditioning (HVAC) system includes a compressor comprising a low pressure input and a high pressure output, the compressor driven by a motor, the motor including a liquid coolant flowpath configured to cool and lubricate the motor and having a liquid coolant input and a liquid coolant output, an evaporator in fluid communication with the compressor, the evaporator including a liquid coolant input, and a vapor coolant output, the vapor coolant output being connected to the low pressure input of the compressor, a condenser in fluid communication with the evaporator and the compressor, the condenser including a vapor cooling input and a liquid coolant output, the vapor cooling input being connected to a high pressure output of the compressor, a first liquid coolant flowpath, including a liquid coolant drive system connecting the liquid coolant output of the condenser to the input of a valve switching device, a second liquid coolant flowpath connecting the liquid coolant output of the condenser to the liquid input of the evapor
- HVAC heating
- the liquid coolant drive system comprises an electric pump.
- HVAC heating ventilation and air conditioning
- HVAC heating ventilation and air conditioning
- HVAC heating ventilation and air conditioning
- HVAC heating ventilation and air conditioning
- the controller is configured to activate the electric pump at least five seconds prior to activating the motor.
- the liquid coolant drive system comprises a liquid coolant reservoir.
- the liquid coolant reservoir is disposed above the motor, relative to a force of gravity, such that a liquid coolant is gravity fed from the reservoir to the motor when the valve switching device is in a first state.
- the liquid coolant reservoir includes an electric heater disposed within the liquid coolant reservoir.
- the electric heater is controllably coupled to a controller, and the controller is configured to activate the electric heater at least 5 minutes prior to activating the motor.
- HVAC heating ventilation and air conditioning
- the second liquid coolant flowpath includes an expansion device connecting the liquid coolant output of the condenser to the liquid input of the evaporator.
- the first liquid coolant flowpath includes a check valve connecting the liquid coolant output of the condenser to the liquid coolant drive system.
- An exemplary method for operating a heating ventilation and air conditioning (HVAC) system includes driving a liquid coolant from a condenser to a compressor motor during a startup sequence of the compressor motor using a liquid coolant drive system, thereby cooling and lubricating the compressor motor, and drawing liquid coolant from the condenser to the compressor motor using a pressure differential between the condenser and an evaporator once the startup sequence has completed.
- HVAC heating ventilation and air conditioning
- HVAC heating ventilation and air conditioning
- HVAC heating ventilation and air conditioning
- HVAC heating ventilation and air conditioning
- HVAC heating ventilation and air conditioning
- FIG. 1 illustrates a high level schematic view compressor motor cooling system for a high speed motor for a heating, ventilation and air condition (HVAC) system.
- HVAC heating, ventilation and air condition
- FIG. 2 schematically illustrates a variation of the configuration of FIG. 1 .
- FIG. 3A schematically illustrates a second variation on the configuration of FIG. 1 .
- FIG. 3B schematically illustrates a variation on the configuration of FIG. 3A .
- FIG. 4 schematically illustrates a third variation on the configuration of FIG. 1 .
- FIG. 1 schematically illustrates a vapor compression system with a compressor motor cooling subsystem 10 for a compressor 20 driven by a high speed motor 22 for HVAC applications.
- the high speed motor 20 is a motor for a mini-centrifugal compressor.
- the system includes a condenser 30 , an evaporator 40 , and an expansion device 11 in fluid communication with the compressor 20 .
- a pressure rise generated by the compressor 20 provides liquid coolant from the condenser 30 to the motor 22 along a fluid flowpath 50 during full speed operations of the compressor 20 .
- the liquid coolant cools and lubricates the motor 22 , and is then provided to the evaporator 40 via the flowpath 58 .
- the coolant is evaporated, and provided to the compressor 20 in a vapor form along a vapor flowpath 60 .
- the vapor flowpath 60 provides the evaporated coolant from the compressor to the condenser 30 .
- the pressure buildup due to the operation of the compressor 20 is sufficient to drive the liquid coolant through the motor 20 and provide the cooling and lubricating effects.
- a liquid coolant driving system 70 provides supplemental pressure to drive the liquid coolant through the motor 20 .
- the liquid coolant driving system 70 can include multiple variations configured to generate the requisite compressor rise. FIGS. 2-4 describe exemplary embodiments of the liquid coolant driving system.
- the flowpath 50 includes a first leg 52 that provides coolant from the condenser 30 to an input of a three-way valve 80 .
- the first leg 52 includes the liquid coolant driving system 70 .
- the three-way valve 80 can be replaced with any other type of valve or regulator capable of regulating flow or flow switching between two input flow sources.
- a second leg 54 that connects the condenser 30 directly to the three-way valve 80 , or other flow switching device, to an expansion device 11 , and to a liquid coolant input of the evaporator 40 .
- a “valve switching device” generically refers to any flow switching device capable of switching a connection of an output between at least two inputs.
- a third leg 56 connects an output of the three-way valve 80 to a liquid coolant input of the motor 22
- a fourth leg 58 connects an output of the motor 22 to the output of the expansion device 11 in the second leg 54 . After merging the coolant flows into the evaporator 40 .
- the three-way valve 80 is set to receive liquid coolant from the condenser 30 via the liquid coolant driving system 70 .
- the liquid coolant driving system 70 drives liquid coolant from the condenser 30 (via the first leg 52 ) to the motor 22 , through the three way valve 80 and the expansion device 11 , as the motor 22 begins operating thereby lubricating and cooling the motor 22 .
- the three way valve 80 switches to receiving the liquid coolant from the second leg 54 , and the liquid coolant driving system 70 is switched off. In this way, coolant is actively provided to the motor 22 directly from the condenser 30 through the second leg 54 , the three way valve 80 and the third leg 56 . Once provided to the evaporator 40 , the liquid coolant evaporates and absorbs heat from another fluid that flows through the evaporator 40 .
- the controller 90 can be a dedicated cooling system controller, a motor controller, or any other controller capable of storing and implementing the control sequences described herein.
- the liquid coolant can be any suitable low global warming potential refrigerant.
- FIG. 2 schematically illustrates an HVAC system 100 , according to the example of FIG. 1 , with the inclusion of a heat driven liquid coolant driving system 170 .
- the heat driven liquid coolant driving system 170 is connected to an outlet of the condenser 130 via a check valve 172 positioned in a first leg 152 of a liquid coolant flowpath 150 .
- the heat driven liquid coolant driving system 170 includes a reservoir 174 , where liquid coolant is pooled.
- the reservoir 174 refers to any component capable of storing liquid refrigerant, and can include oversized lines, a fluid tank, a portion of the condenser, etc.
- an electric heater 176 i.e. a device that generates heat using electricity
- the electric heater 176 raises the temperature of the liquid coolant within the reservoir 174 when activated.
- Alternative heat sources beyond those using electricity to generate heat can be utilized to the same effect with minor modifications to the described system. Raising the temperature in the reservoir 174 increases the pressure in the reservoir 174 , and the increased pressure drives liquid coolant along the second leg 152 of the liquid coolant flowpath when a three way valve 180 connects the first leg 152 of the liquid coolant flow from the reservoir 174 to the third leg 156 of the liquid coolant flowpath.
- the electric heater 176 is activated prior to the activation of the motor 122 . In some examples, this can include activation as many as 5 or 10 minutes prior to motor 122 activation and is governed by controller 90 . The specific length of time by which the activation of the electric heater 176 must precede the activation of the motor 122 is determined by multiple factors including, but not limited to, the volume of coolant, the type of refrigerant, etc. Alternatively, activation of the motor is controlled by the pressure difference between the reservoir 174 and the evaporator 140 .
- FIGS. 3A and 3B illustrate an HVAC system 200 utilizing an electric pump 272 as the liquid coolant driver.
- other means to drive the liquid coolant e.g. electrohydrodynamics, etc.
- the HVAC system 200 is substantially identical to the systems described with regards to FIGS. 1 and 2 , with the exception of the electric pump 272 being utilized to drive the liquid coolant in place of the heat driven liquid coolant driving system 170 of FIG. 2 .
- the electric pump 272 can be included inside the base of the condenser 230 , as shown in the example of FIG.
- the electric pump 272 receives electrical power via a connection to an external power source, such as a building electrical grid, or from an electrical connection to the HVAC system, and is activated by the controller configured to control the motor 220 .
- the electric pump 272 can be any conventional electric pump having sufficient size and power to drive the liquid coolant.
- the pump driven system of FIG. 3A or 3B requires a minimal amount of lead up time after being activated and before the motor 22 can begin startup operations.
- the lead-up time can be less than ten seconds. In some such examples, the lead-up time can be five seconds.
- FIG. 4 illustrates an HVAC system 300 having third variation on the liquid coolant driving system 70 of FIG. 1 .
- the liquid coolant driving system of FIG. 4 utilizes a gravity fed reservoir 374 positioned physically above the motor, relative to a force of gravity, the reservoir is filled with liquid coolant from the condenser 330 .
- the reservoir 374 is connected to an outlet of the condenser 330 via a check valve 372 positioned in a first leg 352 of a liquid coolant loop 350 .
- the three way valve 380 is switched to connecting the reservoir outlet to the motor 322 , gravity causes the liquid coolant to pass through the motor 322 , and allows the motor 322 to begin startup sequences. Due to the continuous application of gravitational forces, no lead-up time beyond the connection of the three-way valve 380 is required before the system of FIG. 4 is able to begin rotating.
- the gravity fed coolant system of FIG. 4 carries with it additional packaging restrictions, and the physical structure of the motor 322 is constructed to support the weight of the liquid coolant reservoir.
- the motor is cooled and lubricated by the liquid coolant provided directly from the condenser by switching the three-way valve to bypass the liquid coolant drive system.
- the liquid coolant flow is adjusted in order to maintain high performance evaporating cooling in the motor and low quality two phase refrigerant leaving from the motor.
Abstract
Description
- The present disclosure relates generally to compressor motor cooling and lubrication, and more specifically to compressor motor cooling and lubrication during a startup sequence.
- This application claims priority to U.S. Provisional Patent Application No. 62/740,476 filed on Oct. 3, 2018.
- Global warming and other environmental concerns have lead the heating, ventilation and cooling (HVAC) industry to explore alternative low Global Warming Potential (GWP) refrigerants in place of existing refrigerants in HVAC systems. However, due to their low pressure characteristics, some low GWP refrigerants, especially those suitable for use in small capacity systems such as rooftops and residential systems, require the utilization of a high-efficiency compressor, evaporator and condenser.
- Certain high-efficiency compressors, such as high speed centrifugal compressors, require a high speed motor for proper operation. High speed motors, however, require that the motor bearings be cooled and lubricated via a cooling system in order to keep the motor system below a limitation temperature and prevent the bearings from overheating. Traditional air cooling of such systems can be inadequate for a high speed motor, and independent oil based liquid cooling leads to complex systems and increases costs.
- In one exemplary embodiment a heating ventilation and air conditioning (HVAC) system includes a compressor comprising a low pressure input and a high pressure output, the compressor driven by a motor, the motor including a liquid coolant flowpath configured to cool and lubricate the motor and having a liquid coolant input and a liquid coolant output, an evaporator in fluid communication with the compressor, the evaporator including a liquid coolant input, and a vapor coolant output, the vapor coolant output being connected to the low pressure input of the compressor, a condenser in fluid communication with the evaporator and the compressor, the condenser including a vapor cooling input and a liquid coolant output, the vapor cooling input being connected to a high pressure output of the compressor, a first liquid coolant flowpath, including a liquid coolant drive system connecting the liquid coolant output of the condenser to the input of a valve switching device, a second liquid coolant flowpath connecting the liquid coolant output of the condenser to the liquid input of the evaporator and to a second input of the valve switching device, a third liquid coolant flowpath connecting an output of the valve switching device to the liquid coolant inputs of the motor, and a fourth liquid coolant flowpath connecting the liquid coolant outputs of the motor to the liquid coolant input of the evaporator.
- In another example of the above described heating ventilation and air conditioning (HVAC) system the liquid coolant drive system comprises an electric pump.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the electric pump is disposed within a reservoir integrated into the condenser.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the electric pump is disposed within a reservoir exterior to the condenser.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the electric pump is disposed outside of the condenser.
- Another example of any of the above described heating ventilation and air conditioning (HVAC) systems further includes a controller controllably connected to the three way valve, the electric pump and the motor.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the controller is configured to activate the electric pump at least five seconds prior to activating the motor.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the liquid coolant drive system comprises a liquid coolant reservoir.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the liquid coolant reservoir is disposed above the motor, relative to a force of gravity, such that a liquid coolant is gravity fed from the reservoir to the motor when the valve switching device is in a first state.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the liquid coolant reservoir includes an electric heater disposed within the liquid coolant reservoir.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the electric heater is controllably coupled to a controller, and the controller is configured to activate the electric heater at least 5 minutes prior to activating the motor.
- Another example of any of the above described heating ventilation and air conditioning (HVAC) systems further includes a one way valve disposed in the first liquid coolant flowpath between the liquid coolant output of the condenser and the input to the reservoir, and oriented such that liquid coolant flows from the condenser to the reservoir and is prevented from flowing from the reservoir to the condenser.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the liquid coolant flowpath includes a liquid phase R1233zd(E) (CHCl=CH=CF3) refrigerant.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the second liquid coolant flowpath includes an expansion device connecting the liquid coolant output of the condenser to the liquid input of the evaporator.
- In another example of any of the above described heating ventilation and air conditioning (HVAC) systems the first liquid coolant flowpath includes a check valve connecting the liquid coolant output of the condenser to the liquid coolant drive system.
- An exemplary method for operating a heating ventilation and air conditioning (HVAC) system includes driving a liquid coolant from a condenser to a compressor motor during a startup sequence of the compressor motor using a liquid coolant drive system, thereby cooling and lubricating the compressor motor, and drawing liquid coolant from the condenser to the compressor motor using a pressure differential between the condenser and an evaporator once the startup sequence has completed.
- In another example of the above described exemplary method for operating a heating ventilation and air conditioning (HVAC) system driving the liquid coolant comprises providing liquid coolant from the condenser to a reservoir and heating the liquid coolant in the reservoir, thereby increasing a pressure of the liquid coolant.
- In another example of any of the above described exemplary methods for operating a heating ventilation and air conditioning (HVAC) system driving the liquid coolant comprises operating an electric pump disposed within the condenser.
- In another example of any of the above described exemplary methods for operating a heating ventilation and air conditioning (HVAC) system driving the liquid coolant comprises operating an electric pump disposed between an outlet of the condenser and a liquid coolant inlet of the compressor motor.
- Another example of any of the above described exemplary methods for operating a heating ventilation and air conditioning (HVAC) system further includes transitioning from driving the liquid coolant using the liquid coolant driving system to drawing liquid coolant from the condenser to the compressor motor using a pressure differential between the condenser and the evaporator in response to the compressor motor exceeding a rotational speed.
- These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
-
FIG. 1 illustrates a high level schematic view compressor motor cooling system for a high speed motor for a heating, ventilation and air condition (HVAC) system. -
FIG. 2 schematically illustrates a variation of the configuration ofFIG. 1 . -
FIG. 3A schematically illustrates a second variation on the configuration ofFIG. 1 . -
FIG. 3B schematically illustrates a variation on the configuration ofFIG. 3A . -
FIG. 4 schematically illustrates a third variation on the configuration ofFIG. 1 . -
FIG. 1 schematically illustrates a vapor compression system with a compressormotor cooling subsystem 10 for acompressor 20 driven by ahigh speed motor 22 for HVAC applications. In one non-limiting example, thehigh speed motor 20 is a motor for a mini-centrifugal compressor. The system includes acondenser 30, anevaporator 40, and an expansion device 11 in fluid communication with thecompressor 20. In order to provide cooling and lubrication to ahigh speed motor 22, a pressure rise generated by thecompressor 20 provides liquid coolant from thecondenser 30 to themotor 22 along afluid flowpath 50 during full speed operations of thecompressor 20. In the embodiment ofFIG. 1 , the liquid coolant cools and lubricates themotor 22, and is then provided to theevaporator 40 via theflowpath 58. Once in theevaporator 40, the coolant is evaporated, and provided to thecompressor 20 in a vapor form along avapor flowpath 60. Thevapor flowpath 60 provides the evaporated coolant from the compressor to thecondenser 30. - Once the
compressor 20 has begun operating at a designed speed, the pressure buildup due to the operation of thecompressor 20 is sufficient to drive the liquid coolant through themotor 20 and provide the cooling and lubricating effects. However, during initial startup there can be insufficient pressure to drive the liquid coolant, and a liquidcoolant driving system 70 provides supplemental pressure to drive the liquid coolant through themotor 20. The liquidcoolant driving system 70 can include multiple variations configured to generate the requisite compressor rise.FIGS. 2-4 describe exemplary embodiments of the liquid coolant driving system. - With regards to the
liquid coolant flowpath 50, theflowpath 50 includes afirst leg 52 that provides coolant from thecondenser 30 to an input of a three-way valve 80. Thefirst leg 52 includes the liquidcoolant driving system 70. In alternative systems, the three-way valve 80 can be replaced with any other type of valve or regulator capable of regulating flow or flow switching between two input flow sources. Also included in theliquid coolant flowpath 50 is asecond leg 54 that connects thecondenser 30 directly to the three-way valve 80, or other flow switching device, to an expansion device 11, and to a liquid coolant input of theevaporator 40. As used herein a “valve switching device” generically refers to any flow switching device capable of switching a connection of an output between at least two inputs. Athird leg 56 connects an output of the three-way valve 80 to a liquid coolant input of themotor 22, and afourth leg 58 connects an output of themotor 22 to the output of the expansion device 11 in thesecond leg 54. After merging the coolant flows into theevaporator 40. - When the
system 10 is initially switched on, the three-way valve 80 is set to receive liquid coolant from thecondenser 30 via the liquidcoolant driving system 70. The liquidcoolant driving system 70 drives liquid coolant from the condenser 30 (via the first leg 52) to themotor 22, through the threeway valve 80 and the expansion device 11, as themotor 22 begins operating thereby lubricating and cooling themotor 22. - Once the
motor 22 is up to speed, and is generating sufficient liquid coolant feeding power due to the pressure buildup within thecondenser 30, the threeway valve 80 switches to receiving the liquid coolant from thesecond leg 54, and the liquidcoolant driving system 70 is switched off. In this way, coolant is actively provided to themotor 22 directly from thecondenser 30 through thesecond leg 54, the threeway valve 80 and thethird leg 56. Once provided to theevaporator 40, the liquid coolant evaporates and absorbs heat from another fluid that flows through theevaporator 40. - Operations of the
motor 22, the three-way valve 80 and the liquidcoolant driving system 70 are controlled via acontroller 90. Thecontroller 90 can be a dedicated cooling system controller, a motor controller, or any other controller capable of storing and implementing the control sequences described herein. - The liquid coolant can be any suitable low global warming potential refrigerant. In one example, the liquid coolant is the refrigerant R1233zd(E) (CHCl=CH=CF3) which has a very low direct global warming potential, a high cycle efficiency, is non-toxic and is non-flammable.
- With continued reference to
FIG. 1 ,FIG. 2 schematically illustrates anHVAC system 100, according to the example ofFIG. 1 , with the inclusion of a heat driven liquidcoolant driving system 170. The heat driven liquidcoolant driving system 170 is connected to an outlet of thecondenser 130 via a check valve 172 positioned in afirst leg 152 of aliquid coolant flowpath 150. The heat driven liquidcoolant driving system 170 includes areservoir 174, where liquid coolant is pooled. As used herein, thereservoir 174 refers to any component capable of storing liquid refrigerant, and can include oversized lines, a fluid tank, a portion of the condenser, etc. - In the embodiment of
FIG. 2 , an electric heater 176 (i.e. a device that generates heat using electricity) is disposed within thereservoir 174, or connected to thereservoir 174 such that theelectric heater 176 raises the temperature of the liquid coolant within thereservoir 174 when activated. Alternative heat sources beyond those using electricity to generate heat can be utilized to the same effect with minor modifications to the described system. Raising the temperature in thereservoir 174 increases the pressure in thereservoir 174, and the increased pressure drives liquid coolant along thesecond leg 152 of the liquid coolant flowpath when a threeway valve 180 connects thefirst leg 152 of the liquid coolant flow from thereservoir 174 to thethird leg 156 of the liquid coolant flowpath. - In order to ensure sufficient pressure is built up within the
reservoir 174, theelectric heater 176 is activated prior to the activation of themotor 122. In some examples, this can include activation as many as 5 or 10 minutes prior tomotor 122 activation and is governed bycontroller 90. The specific length of time by which the activation of theelectric heater 176 must precede the activation of themotor 122 is determined by multiple factors including, but not limited to, the volume of coolant, the type of refrigerant, etc. Alternatively, activation of the motor is controlled by the pressure difference between thereservoir 174 and the evaporator 140. - With continued reference to
FIGS. 1 and 2 ,FIGS. 3A and 3B illustrate anHVAC system 200 utilizing anelectric pump 272 as the liquid coolant driver. In alternative examples, other means to drive the liquid coolant (e.g. electrohydrodynamics, etc.) are can be utilized to pump the liquid coolant without requiring an electrically drivenpump 272. TheHVAC system 200 is substantially identical to the systems described with regards toFIGS. 1 and 2 , with the exception of theelectric pump 272 being utilized to drive the liquid coolant in place of the heat driven liquidcoolant driving system 170 ofFIG. 2 . Theelectric pump 272 can be included inside the base of thecondenser 230, as shown in the example ofFIG. 3A , or can be outside of thecondenser 230 within the firstliquid coolant flowpath 252. In both cases, theelectric pump 272 receives electrical power via a connection to an external power source, such as a building electrical grid, or from an electrical connection to the HVAC system, and is activated by the controller configured to control themotor 220. Theelectric pump 272 can be any conventional electric pump having sufficient size and power to drive the liquid coolant. - Unlike the heat driven liquid
coolant driving system 170 ofFIG. 2 , the pump driven system ofFIG. 3A or 3B requires a minimal amount of lead up time after being activated and before themotor 22 can begin startup operations. By way of example, the lead-up time can be less than ten seconds. In some such examples, the lead-up time can be five seconds. - With continued reference to
FIGS. 1-3B ,FIG. 4 illustrates an HVAC system 300 having third variation on the liquidcoolant driving system 70 ofFIG. 1 . The liquid coolant driving system ofFIG. 4 utilizes a gravity fedreservoir 374 positioned physically above the motor, relative to a force of gravity, the reservoir is filled with liquid coolant from thecondenser 330. Thereservoir 374 is connected to an outlet of thecondenser 330 via acheck valve 372 positioned in afirst leg 352 of aliquid coolant loop 350. When the threeway valve 380 is switched to connecting the reservoir outlet to themotor 322, gravity causes the liquid coolant to pass through themotor 322, and allows themotor 322 to begin startup sequences. Due to the continuous application of gravitational forces, no lead-up time beyond the connection of the three-way valve 380 is required before the system ofFIG. 4 is able to begin rotating. - In some examples, the gravity fed coolant system of
FIG. 4 carries with it additional packaging restrictions, and the physical structure of themotor 322 is constructed to support the weight of the liquid coolant reservoir. - With reference now to all of
FIGS. 1-4 , after the initial startup the motor is cooled and lubricated by the liquid coolant provided directly from the condenser by switching the three-way valve to bypass the liquid coolant drive system. The liquid coolant flow is adjusted in order to maintain high performance evaporating cooling in the motor and low quality two phase refrigerant leaving from the motor. - It is further understood that any of the above described concepts can be used alone or in combination with any or all of the other above described concepts. Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
Claims (20)
Priority Applications (1)
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US16/973,567 US20210247107A1 (en) | 2018-10-03 | 2019-08-30 | Method and system for cooling a motor during motor startup |
Applications Claiming Priority (3)
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US201862740476P | 2018-10-03 | 2018-10-03 | |
US16/973,567 US20210247107A1 (en) | 2018-10-03 | 2019-08-30 | Method and system for cooling a motor during motor startup |
PCT/US2019/049019 WO2020072154A1 (en) | 2018-10-03 | 2019-08-30 | Method and system for cooling a motor during motor startup |
Publications (1)
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US20210247107A1 true US20210247107A1 (en) | 2021-08-12 |
Family
ID=67957411
Family Applications (1)
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US16/973,567 Abandoned US20210247107A1 (en) | 2018-10-03 | 2019-08-30 | Method and system for cooling a motor during motor startup |
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US (1) | US20210247107A1 (en) |
CN (1) | CN112334718B (en) |
WO (1) | WO2020072154A1 (en) |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2891391A (en) * | 1957-08-26 | 1959-06-23 | Vilter Mfg Co | Refrigerated hermetically sealed motors |
JP3443443B2 (en) * | 1993-12-24 | 2003-09-02 | 株式会社神戸製鋼所 | Screw refrigerator |
EP0730128B1 (en) * | 1995-02-06 | 1999-06-23 | Carrier Corporation | Fuzzy logic control of liquid injection for motor cooling |
JP2003159933A (en) * | 2001-11-26 | 2003-06-03 | Sanyo Electric Co Ltd | Cooling means for compressor for car air conditioner |
WO2009088846A1 (en) * | 2007-12-31 | 2009-07-16 | Johnson Controls Technology Company | Method and system for rotor cooling |
WO2013039572A1 (en) * | 2011-09-16 | 2013-03-21 | Danfoss Turbocor Compressors B.V. | Motor cooling and sub-cooling circuits for compressor |
CN108278210B (en) * | 2013-02-05 | 2019-09-06 | 艾默生环境优化技术有限公司 | Compressor cooling system |
TWI577949B (en) * | 2013-02-21 | 2017-04-11 | 強生控制科技公司 | Lubrication and cooling system |
CN105164476A (en) * | 2013-05-02 | 2015-12-16 | 开利公司 | Compressor bearing cooling via purge unit |
CN204345959U (en) * | 2014-12-15 | 2015-05-20 | 珠海格力电器股份有限公司 | Air-conditioner |
-
2019
- 2019-08-30 WO PCT/US2019/049019 patent/WO2020072154A1/en active Application Filing
- 2019-08-30 CN CN201980042609.6A patent/CN112334718B/en active Active
- 2019-08-30 US US16/973,567 patent/US20210247107A1/en not_active Abandoned
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CN112334718B (en) | 2023-10-31 |
CN112334718A (en) | 2021-02-05 |
WO2020072154A1 (en) | 2020-04-09 |
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