CA2885755A1 - Variable refrigerant charge control - Google Patents
Variable refrigerant charge control Download PDFInfo
- Publication number
- CA2885755A1 CA2885755A1 CA2885755A CA2885755A CA2885755A1 CA 2885755 A1 CA2885755 A1 CA 2885755A1 CA 2885755 A CA2885755 A CA 2885755A CA 2885755 A CA2885755 A CA 2885755A CA 2885755 A1 CA2885755 A1 CA 2885755A1
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- Canada
- Prior art keywords
- reservoir
- refrigerant
- line
- refrigerant charge
- liquid line
- Prior art date
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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
- F25B45/00—Arrangements for charging or discharging 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
- 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
-
- 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
- F25B13/00—Compression machines, plants or systems, with reversible cycle
-
- 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
- F25B2400/05—Compression system with heat exchange between particular parts of the system
- F25B2400/053—Compression system with heat exchange between particular parts of the system between the storage receiver and another part of the system
-
- 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
- F25B2400/05—Compression system with heat exchange between particular parts of the system
- F25B2400/054—Compression system with heat exchange between particular parts of the system between the suction tube of the compressor and another part of the cycle
-
- 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
-
- 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
- F25B2400/19—Pumping down refrigerant from one part of the cycle to another part of the cycle, e.g. when the cycle is changed from cooling to heating, or before a defrost cycle is started
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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
- F25B2600/25—Control of valves
- F25B2600/2519—On-off valves
-
- 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
- F25B2600/25—Control of valves
- F25B2600/2523—Receiver valves
-
- 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
- F25B2700/19—Pressures
- F25B2700/195—Pressures of the condenser
-
- 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
- F25B2700/21—Temperatures
- F25B2700/2116—Temperatures of a condenser
- F25B2700/21163—Temperatures of a condenser of the refrigerant at the outlet of the condenser
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Air Conditioning Control Device (AREA)
Abstract
An apparatus and method for adjusting refrigerant charge level are provided.
The apparatus has a reservoir, a reservoir line, a reservoir valve, and one or more side valves. The reservoir line connects the reservoir and a liquid line, and has a connection to the liquid line.
The liquid line connects an indoor heat exchanger and an outdoor heat exchanger. The reservoir valve is on the reservoir line. The one or more side valves are on the liquid line. In the method, an indicator of effectiveness of a refrigerant-using system is calculated. The indicator is compared to a target indicator of effectiveness. A refrigerant charge level is adjusted to reduce the difference between the indicator and the target indicator.
The apparatus has a reservoir, a reservoir line, a reservoir valve, and one or more side valves. The reservoir line connects the reservoir and a liquid line, and has a connection to the liquid line.
The liquid line connects an indoor heat exchanger and an outdoor heat exchanger. The reservoir valve is on the reservoir line. The one or more side valves are on the liquid line. In the method, an indicator of effectiveness of a refrigerant-using system is calculated. The indicator is compared to a target indicator of effectiveness. A refrigerant charge level is adjusted to reduce the difference between the indicator and the target indicator.
Description
VARIABLE REFRIGERANT CHARGE CONTROL
TECHNICAL FIELD
[0001] This application relates to HVAC systems and, more particularly, to HVAC refrigerant charge levels.
BACKGROUND
TECHNICAL FIELD
[0001] This application relates to HVAC systems and, more particularly, to HVAC refrigerant charge levels.
BACKGROUND
[0002] One area that has not been fully optimized in Heating, Ventilation, and Air Conditioning (HVAC) systems is the refrigerant charge level. Variable speed compressor technology greatly increased the efficiency of HVAC systems by allowing the compressor speed to be better adjusted to match the load on the system. However, the refrigerant charge level (amount of refrigerant in the system) in a conventional HVAC system remains the same regardless of the load on the system. The refrigerant charge level is therefore optimized for a single operating condition. It would be desirable if a HVAC system could optimize its refrigerant charge level for the current operating condition.
SUMMARY
SUMMARY
[0003] In an embodiment, an apparatus for adjusting refrigerant charge level is provided.
The apparatus has a reservoir, a reservoir line, a reservoir valve, and one or more side valves.
The reservoir line connects the reservoir and a liquid line, and has a connection to the liquid line.
The liquid line connects an indoor heat exchanger and an outdoor heat exchanger. The reservoir valve is on the reservoir line. The one or more side valves are on the liquid line.
The apparatus has a reservoir, a reservoir line, a reservoir valve, and one or more side valves.
The reservoir line connects the reservoir and a liquid line, and has a connection to the liquid line.
The liquid line connects an indoor heat exchanger and an outdoor heat exchanger. The reservoir valve is on the reservoir line. The one or more side valves are on the liquid line.
[0004] In another embodiment, a method for adjusting refrigerant charge level is provided. An indicator of effectiveness of a refrigerant-using system is calculated. The indicator is compared to a target indicator of effectiveness. A refrigerant charge level is adjusted to reduce the difference between the indicator and the target indicator.
DESCRIPTION OF DRAWINGS
DESCRIPTION OF DRAWINGS
[0005] For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following Detailed Description taken in conjunction with the accompanying drawings, in which:
FIG. 1 depicts a HVAC system with a refrigerant charge control apparatus;
FIG. 2A depicts the refrigerant charge control apparatus configured for normal operation;
FIG. 2B depicts the refrigerant charge control apparatus configured to fill a reservoir during cooling;
FIG. 2C depicts the refrigerant charge control apparatus configured to fill the reservoir during heating;
FIG. 2D depicts the refrigerant charge control apparatus configured to drain the reservoir using gravity;
FIG. 2E depicts the refrigerant charge control apparatus configured to drain during cooling;
FIG. 2F depicts the refrigerant charge control apparatus configured to drain during heating;
FIG. 3 depicts a HVAC system with an alternate refrigerant charge control apparatus;
FIG. 4A depicts the alternate refrigerant charge control apparatus configured for normal operation;
FIG. 4B depicts the alternate refrigerant charge control apparatus configured to fill a reservoir;
FIG. 4C depicts the alternate refrigerant charge control apparatus configured to drain the reservoir during cooling;
FIG. 4D depicts the alternate refrigerant charge control apparatus configured to drain the reservoir during heating;
FIG. 5 depicts a method which a controller may perform to use a subcooling value to control the refrigerant charge; and FIG. 6 depicts a method which a controller may perform to use an Energy Efficiency Ratio (EER) to control the refrigerant charge.
DETAILED DESCRIPTION
FIG. 1 depicts a HVAC system with a refrigerant charge control apparatus;
FIG. 2A depicts the refrigerant charge control apparatus configured for normal operation;
FIG. 2B depicts the refrigerant charge control apparatus configured to fill a reservoir during cooling;
FIG. 2C depicts the refrigerant charge control apparatus configured to fill the reservoir during heating;
FIG. 2D depicts the refrigerant charge control apparatus configured to drain the reservoir using gravity;
FIG. 2E depicts the refrigerant charge control apparatus configured to drain during cooling;
FIG. 2F depicts the refrigerant charge control apparatus configured to drain during heating;
FIG. 3 depicts a HVAC system with an alternate refrigerant charge control apparatus;
FIG. 4A depicts the alternate refrigerant charge control apparatus configured for normal operation;
FIG. 4B depicts the alternate refrigerant charge control apparatus configured to fill a reservoir;
FIG. 4C depicts the alternate refrigerant charge control apparatus configured to drain the reservoir during cooling;
FIG. 4D depicts the alternate refrigerant charge control apparatus configured to drain the reservoir during heating;
FIG. 5 depicts a method which a controller may perform to use a subcooling value to control the refrigerant charge; and FIG. 6 depicts a method which a controller may perform to use an Energy Efficiency Ratio (EER) to control the refrigerant charge.
DETAILED DESCRIPTION
[0006] In the following discussion, numerous specific details are set forth to provide a thorough explanation. However, such specific details are not essential. In other instances, well-known elements have been illustrated in schematic or block diagram form.
Additionally, for the most part, specific details within the understanding of persons of ordinary skill in the relevant art have been omitted.
Additionally, for the most part, specific details within the understanding of persons of ordinary skill in the relevant art have been omitted.
[0007] With reference to FIG. 1, depicted is a Heating, Ventilation, and Air Conditioning (HVAC) system 100 with a refrigerant charge control apparatus 101. System 100 includes indoor unit 102, outdoor unit 104, and controller 105. Indoor unit 102 would be located inside a structure to be heated or cooled, such as a building or refrigerator. Outdoor unit 104 would be located outside the structure. This combination of an indoor unit and an outdoor unit is generally used in residential HVAC systems but may also be used in other applications, such as refrigeration.
[0008] Prior to the operation of apparatus 101, HVAC system 100 operates conventionally.
A continuous flow of refrigerant moves in a loop through HVAC system 100. This loop may be called the "vapor compression cycle." Compressor 106 compresses refrigerant in gas vapor form, and then discharges the refrigerant through discharge line 108. The compressed refrigerant gas vapor enters reversing valve 110. Reversing valve 110 can change between a cooling configuration, shown by solid lines, and a heating configuration, shown by dashed lines.
A continuous flow of refrigerant moves in a loop through HVAC system 100. This loop may be called the "vapor compression cycle." Compressor 106 compresses refrigerant in gas vapor form, and then discharges the refrigerant through discharge line 108. The compressed refrigerant gas vapor enters reversing valve 110. Reversing valve 110 can change between a cooling configuration, shown by solid lines, and a heating configuration, shown by dashed lines.
[0009] In the cooling configuration, the refrigerant flows from reversing valve 110 to outdoor heat exchanger 112. The refrigerant flows through outdoor heat exchanger 112, releasing heat into the outdoor air and condensing into a liquid. From outdoor heat exchanger 112, the liquid refrigerant flows through liquid line 114.
[0010] Liquid line 114 has expansion device 116A and expansion device 116B.
Expansion devices 116A and 116B expand liquid refrigerant flowing through them, reducing the pressure of the refrigerant. However, due to check valves or the like, expansion device 116A only acts on refrigerant flowing toward outdoor heat exchanger 112, and expansion device 116B only acts on refrigerant flowing toward indoor heat exchanger 118. Refrigerant flowing in the opposite directions, through expansion device 116A toward indoor heat exchanger 118 or through expansion device 116B toward outdoor heat exchanger 112, bypasses the respective expansion device and does not expand.
Expansion devices 116A and 116B expand liquid refrigerant flowing through them, reducing the pressure of the refrigerant. However, due to check valves or the like, expansion device 116A only acts on refrigerant flowing toward outdoor heat exchanger 112, and expansion device 116B only acts on refrigerant flowing toward indoor heat exchanger 118. Refrigerant flowing in the opposite directions, through expansion device 116A toward indoor heat exchanger 118 or through expansion device 116B toward outdoor heat exchanger 112, bypasses the respective expansion device and does not expand.
[0011] The liquid refrigerant bypasses expansion device 116A and flows to expansion device 116B. Expansion device 116B reduces the pressure of the liquid refrigerant flowing through it.
The refrigerant then flows through indoor heat exchanger 118, absorbing heat from the structure and evaporating into a gas vapor. The refrigerant then flows to reversing valve 110, where it is directed through suction line 120 and back into compressor 106 to be compressed again.
The refrigerant then flows through indoor heat exchanger 118, absorbing heat from the structure and evaporating into a gas vapor. The refrigerant then flows to reversing valve 110, where it is directed through suction line 120 and back into compressor 106 to be compressed again.
[0012] In the heating configuration, the refrigerant flows from reversing valve 110 to indoor heat exchanger 118. The refrigerant flows through indoor heat exchanger 118, releasing heat into the structure and condensing into a liquid. From indoor heat exchanger 118, the liquid . .
refrigerant flows through liquid line 114. The liquid refrigerant bypasses expansion device 116B
and flows to expansion device 116A. Expansion device 116A reduces the pressure of the liquid refrigerant flowing through it. The refrigerant then flows through outdoor heat exchanger 112, absorbing heat from the outdoor air and evaporating into a gas vapor. The refrigerant then flows to reversing valve 110, where it is directed through suction line 120 and back into compressor 106 to be compressed again.
refrigerant flows through liquid line 114. The liquid refrigerant bypasses expansion device 116B
and flows to expansion device 116A. Expansion device 116A reduces the pressure of the liquid refrigerant flowing through it. The refrigerant then flows through outdoor heat exchanger 112, absorbing heat from the outdoor air and evaporating into a gas vapor. The refrigerant then flows to reversing valve 110, where it is directed through suction line 120 and back into compressor 106 to be compressed again.
[0013] Outdoor heat exchanger 112 may be called the outdoor coil.
Indoor heat exchanger 118 may be called the indoor coil. During cooling, outdoor heat exchanger 112 may be called the condenser and indoor heat exchanger 118 may be called the evaporator.
During heating, outdoor heat exchanger 112 may be called the evaporator and indoor heat exchanger 118 may be called the condenser. Expansion devices 116A and 116B may be expansion valves.
Indoor heat exchanger 118 may be called the indoor coil. During cooling, outdoor heat exchanger 112 may be called the condenser and indoor heat exchanger 118 may be called the evaporator.
During heating, outdoor heat exchanger 112 may be called the evaporator and indoor heat exchanger 118 may be called the condenser. Expansion devices 116A and 116B may be expansion valves.
[0014] Refrigerant charge control apparatus 101 comprises reservoir line 124, reservoir 126, reservoir valve 128A, indoor side valve 128B, and outdoor side valve 128C.
Reservoir line 124 connects liquid line 114 to reservoir 126. Reservoir 126 may be a tank which holds excess refrigerant.
Reservoir line 124 connects liquid line 114 to reservoir 126. Reservoir 126 may be a tank which holds excess refrigerant.
[0015] Reservoir valve 128A may be positioned on reservoir line 124.
Indoor side valve 128B may be positioned on liquid line 114 between reservoir line 124 and indoor heat exchanger 118. Outdoor side valve 128C may be positioned on liquid line 114 between reservoir line 124 and outdoor heat exchanger 112. Valves 128A, 128B, and 128C can each be opened, to permit the flow of refrigerant, or closed, to block the flow of refrigerant. Valves 128A, 128B, and 128C
may be solenoid valves.
Indoor side valve 128B may be positioned on liquid line 114 between reservoir line 124 and indoor heat exchanger 118. Outdoor side valve 128C may be positioned on liquid line 114 between reservoir line 124 and outdoor heat exchanger 112. Valves 128A, 128B, and 128C can each be opened, to permit the flow of refrigerant, or closed, to block the flow of refrigerant. Valves 128A, 128B, and 128C
may be solenoid valves.
[0016] Indoor side valve 128B and outdoor side valve 128C are called "indoor" and "outdoor" to identify their locations relative to reservoir line 124 and heat exchangers 112 and 118. The "indoor" and "outdoor" names do not identify whether the valves 128B-C are indoors or outdoors. Indoor side valve 128B may be located indoors or outdoors.
Outdoor side valve 128C may be located indoors or outdoors.
Outdoor side valve 128C may be located indoors or outdoors.
[0017] Refrigerant charge control apparatus 101 can be operated to fill reservoir 126 with refrigerant from liquid line 114, reducing the amount of refrigerant for compressor 106 to compress. Refrigerant charge control apparatus 101 can also be operated to drain refrigerant from reservoir 126 into liquid line 114, increasing the amount of refrigerant for compressor 106 to compress.
[0018] Controller 105 operates valves 128A, 128B, and 128C to adjust the "refrigerant charge level," the amount of refrigerant in the vapor compression cycle. Where valves 128A-C
are solenoid valves, controller 105 may send current through valves 128A-C
directly or send a signal that causes current to be sent through valves 128A-C. Controller 105 may be a unit controller that controls the overall operation of units 102 and 104, or may be a separate controller that only controls the refrigerant charge level.
are solenoid valves, controller 105 may send current through valves 128A-C
directly or send a signal that causes current to be sent through valves 128A-C. Controller 105 may be a unit controller that controls the overall operation of units 102 and 104, or may be a separate controller that only controls the refrigerant charge level.
[0019] With reference to FIG. 2A, depicted is a configuration 200A of refrigerant charge control apparatus 101 in normal operation, when reservoir 126 is not being drained or filled.
Reservoir valve 128A is closed, indoor side valve 128B is open, and outdoor side valve 128C is open. Refrigerant flows through liquid line 114 as it would in the absence of refrigerant charge control apparatus 101. In FIG. 2A, refrigerant would flow through liquid line 114 from left to right during cooling and from right to left during heating.
Reservoir valve 128A is closed, indoor side valve 128B is open, and outdoor side valve 128C is open. Refrigerant flows through liquid line 114 as it would in the absence of refrigerant charge control apparatus 101. In FIG. 2A, refrigerant would flow through liquid line 114 from left to right during cooling and from right to left during heating.
[0020] With reference to FIG. 2B, depicted is a configuration 200B of refrigerant charge control apparatus 101. In configuration 200B, refrigerant charge control apparatus 101 is configured to fill reservoir 126 during cooling. Reservoir valve 128A and outdoor side valve 128C are open, while indoor side valve 128B is closed. Refrigerant 202 flowing from outdoor heat exchanger 112 through liquid line 114 is blocked by indoor side valve 128B. Refrigerant 202 is instead forced through reservoir line 124 into reservoir 126. After charge is added to reservoir 126, refrigerant charge control apparatus 101 may return to configuration 200A.
[0021] With reference to FIG. 2C, depicted is a configuration 200C of refrigerant charge control apparatus 101. In configuration 200C, refrigerant charge control apparatus 101 is configured to fill reservoir 126 during heating. Reservoir valve 128A and indoor side valve 128B are open, while outdoor side valve 128C is closed. Refrigerant 202 flowing from indoor heat exchanger 118 through liquid line 114 is blocked by outdoor side valve 128C. Refrigerant 202 is instead forced through reservoir line 124 into reservoir 126. After charge is added to reservoir 126, refrigerant charge control apparatus 101 may return to configuration 200A.
[0022] With reference to FIG. 2D, depicted is a configuration 200D of refrigerant charge control apparatus 101. In configuration 200D, refrigerant charge control apparatus 101 is configured to drain reservoir 126 using gravity. Indoor side valve 128B and outdoor side valve 128C are open, allowing refrigerant 202 to flow through liquid line 114 normally. Reservoir valve 128A is also open, allowing gravity to drain refrigerant 202 in reservoir 126 into liquid line 114. In FIG. 2D, refrigerant would flow through liquid line 114 from left to right during cooling and from right to left during heating. After charge is removed from reservoir 126, refrigerant charge control apparatus 101 may return to configuration 200A.
[0023] Because configuration 200D depends on gravity, to use configuration 200D reservoir 126 should be placed above liquid line 114. As an alternative to configuration 200D, configurations 200B and 200C can be used to drain reservoir 126 using a pressure difference.
Reservoir 126 may therefore be placed at the same height as or lower than liquid line 114. If reservoir 126 is above liquid line 114, gravity can still aid configurations 200B and 200C in draining reservoir 126.
Reservoir 126 may therefore be placed at the same height as or lower than liquid line 114. If reservoir 126 is above liquid line 114, gravity can still aid configurations 200B and 200C in draining reservoir 126.
[0024] Referring to FIG. 2E, depicted is configuration 200C used to drain reservoir 126 during cooling. Outdoor side valve 128C is closed, blocking the flow of refrigerant from outdoor heat exchanger 112 and reducing the pressure on the other side of outdoor side valve 128C. Reservoir valve 128A and indoor side valve 128B are open. The reduced pressure draws refrigerant from reservoir 126 into liquid line 114. After charge is removed from reservoir 126, refrigerant charge control apparatus 101 may return to configuration 200A.
[0025] Referring to FIG. 2F, depicted is configuration 200B used to drain reservoir 126 during heating. Indoor side valve 128B is closed, blocking the flow of refrigerant from indoor heat exchanger 118 and reducing the pressure on the other side of indoor side valve 128B.
Reservoir valve 128A and outdoor side valve 128C are open. The reduced pressure draws refrigerant from reservoir 126 into liquid line 114. After charge is removed from reservoir 126, refrigerant charge control apparatus 101 may return to configuration 200A.
Reservoir valve 128A and outdoor side valve 128C are open. The reduced pressure draws refrigerant from reservoir 126 into liquid line 114. After charge is removed from reservoir 126, refrigerant charge control apparatus 101 may return to configuration 200A.
[0026] With reference to FIG. 3, depicted is a Heating, Ventilation, and Air Conditioning (HVAC) system 300 with an alternate refrigerant charge control apparatus 301.
System 300 is identical to system 100 except that apparatus 301 has been substituted for apparatus 101.
Refrigerant charge control apparatus 301 comprises reservoir line 124, reservoir 302, reservoir valve 128A, indoor side valve 128B, and outdoor side valve 128C. Reservoir line 124 may connect liquid line 114 to reservoir 302. Valves 128A, 128B, and 128C may be positioned as in apparatus 101. Controller 105 operates valves 128A, 128B, and 128C to adjust the refrigerant charge level.
System 300 is identical to system 100 except that apparatus 301 has been substituted for apparatus 101.
Refrigerant charge control apparatus 301 comprises reservoir line 124, reservoir 302, reservoir valve 128A, indoor side valve 128B, and outdoor side valve 128C. Reservoir line 124 may connect liquid line 114 to reservoir 302. Valves 128A, 128B, and 128C may be positioned as in apparatus 101. Controller 105 operates valves 128A, 128B, and 128C to adjust the refrigerant charge level.
[0027] Reservoir 302 may be a tank which holds excess refrigerant. Suction line 120 passes through reservoir 302, and may pass through the middle of reservoir 302.
Refrigerant stored in reservoir 302 does not flow through suction line 120 into compressor 106. A
tank with a suction line passing through it is commonly called a charge compensator.
Refrigerant stored in reservoir 302 does not flow through suction line 120 into compressor 106. A
tank with a suction line passing through it is commonly called a charge compensator.
[0028] With reference to FIG. 4A, depicted is a configuration 400A of refrigerant charge control apparatus 301 in normal operation, when reservoir 302 is not being drained or filled.
Reservoir valve 128A is closed, indoor side valve 128B is open, and outdoor side valve 128C is open. Refrigerant flows through liquid line 114 as it would in the absence of refrigerant charge control apparatus 301. In FIG. 4A, refrigerant would flow through liquid line 114 from left to right during cooling and from right to left during heating.
Reservoir valve 128A is closed, indoor side valve 128B is open, and outdoor side valve 128C is open. Refrigerant flows through liquid line 114 as it would in the absence of refrigerant charge control apparatus 301. In FIG. 4A, refrigerant would flow through liquid line 114 from left to right during cooling and from right to left during heating.
[0029] With reference to FIG. 4B, depicted is a configuration 400B of refrigerant charge control apparatus 301. In configuration 400B, refrigerant charge control apparatus 301 is configured to fill reservoir 302. Reservoir valve 128A, indoor side valve 128B, and outdoor side valve 128C are open. The refrigerant passing through suction line 120 is cooler than the refrigerant passing through liquid line 114. The temperature difference draws refrigerant from liquid line 114 through reservoir line 124 and into reservoir 302. After charge is added to reservoir 302, refrigerant charge control apparatus 301 may return to configuration 400A.
[0030] With reference to FIG. 4C, depicted is a configuration 400C of refrigerant charge control apparatus 301. In configuration 400C, refrigerant charge control apparatus 301 is configured to drain reservoir 302 during cooling. Reservoir valve 128A and indoor side valve 128B are open, while outdoor side valve 128C is closed. The closed outdoor side valve 128C
blocks the flow of refrigerant through liquid line 114, reducing the pressure in liquid line 114 after valve 128C below the pressure in suction line 120. Refrigerant drains from reservoir 302 into liquid line 114 and flows toward indoor heat exchanger 118. After charge is removed from reservoir 302, refrigerant charge control apparatus 301 may return to configuration 400A.
blocks the flow of refrigerant through liquid line 114, reducing the pressure in liquid line 114 after valve 128C below the pressure in suction line 120. Refrigerant drains from reservoir 302 into liquid line 114 and flows toward indoor heat exchanger 118. After charge is removed from reservoir 302, refrigerant charge control apparatus 301 may return to configuration 400A.
[0031] With reference to FIG. 4D, depicted is a configuration 400D of refrigerant charge control apparatus 301. In configuration 400D, refrigerant charge control apparatus 301 is configured to drain reservoir 302 during heating. Reservoir valve 128A and outdoor side valve 128C are open, while indoor side valve 128B is closed. The closed indoor side valve 128B
blocks the flow of refrigerant through liquid line 114, reducing the pressure in liquid line 114 after valve 128B below the pressure in suction line 120. Refrigerant drains from reservoir 302 into liquid line 114 and flows toward outdoor heat exchanger 112. After charge is removed from reservoir 302, refrigerant charge control apparatus 301 may return to configuration 400A.
blocks the flow of refrigerant through liquid line 114, reducing the pressure in liquid line 114 after valve 128B below the pressure in suction line 120. Refrigerant drains from reservoir 302 into liquid line 114 and flows toward outdoor heat exchanger 112. After charge is removed from reservoir 302, refrigerant charge control apparatus 301 may return to configuration 400A.
[0032] HVAC systems 100 and 300 are capable of both heating and cooling. A
system which can perform both may be called a heat pump. In a HVAC system which is capable of one of heating or cooling, but not both, one of valves 128B and 128C may be removed. In a HVAC
system which is only capable of heating, also called a heater, indoor side valve 128B is unnecessary. In a HVAC system which is only capable of cooling, also called an air conditioner, outdoor side valve 128C is unnecessary. An exception is a refrigerant charge control apparatus 101 which relies on configuration 200B or 200C to drain reservoir 126. In such an apparatus 101, both valves 128B and 128C are used even if the HVAC system is only capable of one of heating or cooling.
system which can perform both may be called a heat pump. In a HVAC system which is capable of one of heating or cooling, but not both, one of valves 128B and 128C may be removed. In a HVAC
system which is only capable of heating, also called a heater, indoor side valve 128B is unnecessary. In a HVAC system which is only capable of cooling, also called an air conditioner, outdoor side valve 128C is unnecessary. An exception is a refrigerant charge control apparatus 101 which relies on configuration 200B or 200C to drain reservoir 126. In such an apparatus 101, both valves 128B and 128C are used even if the HVAC system is only capable of one of heating or cooling.
[0033] Additionally, in a heater or air conditioner, reversing valve 110 is unnecessary because the direction of refrigerant flow does not reverse. Expansion device 116A is also unnecessary in an air conditioner because refrigerant does not flow through liquid line 114 toward outdoor heat exchanger 112. Expansion device 116B is also unnecessary in a heater because refrigerant does not flow through liquid line 114 toward indoor heat exchanger 118.
[0034] Refrigerant charge control apparatuses 101 and 301 are shown inside outdoor unit 104. However, this is not necessarily the case. Refrigerant charge control apparatuses 101 and 301 may also be inside indoor unit 102.
[0035] Refrigerant charge control apparatuses 101 and 301 may fill or drain their respective reservoirs by cycling between the normal operation configuration and a fill or drain configuration. For instance, refrigerant charge control apparatus 101 does not necessarily change to configuration 200B, wait for reservoir 126 to fill sufficiently, and then change to configuration 200A. Refrigerant charge control apparatus 101 could alternately begin cycling between configuration 200B and configuration 200A until reservoir 126 fills sufficiently, then change to configuration 200A.
[0036] Depending on tubing size, using simple solenoid valves for valves 128A, 128B, and 128C may result in refrigerant flow that is too fast. In an embodiment, valves 128A, 128B, and 128C are electronic flow valves with variable flow rates. When an electronic flow valve 128A, 128B, or 128C is opened, controller 105 may adjust the flow rate of the open valve to adjust the rate reservoir 126 or 302 fills or drains.
[0037] Compressor 106 is preferably a variable speed compressor, which can operate at a wide range of possible speeds. Compressor 106 may also be a multiple stage compressor, which can operate at a few discrete speeds. Compressor 106 may also be a single stage compressor, which operates at only a single speed. However, the benefit of adjusting the refrigerant charge increases with the range of speeds compressor 106 is capable of. With a single stage compressor 106, the benefit is very limited. The benefit is also less with a multiple stage compressor 106 than a variable speed compressor 106.
[0038] With a variable speed or multiple stage compressor 106, the speed of compressor 106 increases when the load on the HVAC system is high and decreases when the load on the HVAC
system is low. Generally speaking, when there is a relatively low load on the HVAC system, the refrigerant charge level should be relatively high. Ideally, only liquid refrigerant should leave the expansion device which expands the refrigerant. This expansion device is 116B in the cooling configuration and 116A in the heating configuration. If the refrigerant charge level is too low, a mixture of liquid and gas refrigerant will leave the expansion device, which will reduce the performance of the evaporator coil.
system is low. Generally speaking, when there is a relatively low load on the HVAC system, the refrigerant charge level should be relatively high. Ideally, only liquid refrigerant should leave the expansion device which expands the refrigerant. This expansion device is 116B in the cooling configuration and 116A in the heating configuration. If the refrigerant charge level is too low, a mixture of liquid and gas refrigerant will leave the expansion device, which will reduce the performance of the evaporator coil.
[0039] Likewise, when there is a relatively high load on the HVAC system, the refrigerant charge level should be relatively low. Less refrigerant is needed to keep gas refrigerant from leaving the expansion device which expands the refrigerant. At the same time, unnecessary refrigerant increases the pressure of the refrigerant in the vapor compression cycle and additional power is used moving that excess refrigerant.
[0040] However, this inverse relationship between load and optimal refrigerant charge level is only true in general. It is possible to have too high a refrigerant charge level with a low load or too low a refrigerant charge level with a high load. Thus, it is not necessarily possible to determine whether the refrigerant charge level should be increased or decreased solely from the present load on the HVAC system.
[0041] With reference to FIG. 5, depicted is a method 500 which controller 105 may perform to control the refrigerant charge level. Method 500 uses a subcooling value to determine whether the refrigerant charge level should be changed. When the gas refrigerant passes through the condenser and changes into a liquid, the temperature of the refrigerant falls but the refrigerant remains at the same pressure. The subcooling value is the amount the temperature falls below the saturation temperature of the refrigerant for that pressure. The subcooling value is a measure of the effectiveness of the system 100 or 300.
[0042] Controller 105 may have a memory which stores target subcooling values for a given load on the HVAC system. The target subcooling values represent an ideal subcooling value when the refrigerant charge level is optimized for a given load. These target subcooling values may be determined during testing or simulation of the HVAC system.
[0043] At 502, controller 105 may measure the temperature and pressure of the liquid leaving the condenser. At 504, controller 105 may calculate the subcooling value from the temperature and pressure. At 506, controller 105 may compare the subcooling value to the target subcooling value for the present operating load.
[0044] At 508, controller 105 may operate valves 128A, 128B, and 128C on charge control apparatus 101 or charge control apparatus 103 to adjust the refrigerant charge level. Whether to increase or decrease the refrigerant charge level may be a matter of trial and error for controller 105, based on whether the last adjustment to the refrigerant charge level brought the subcooling value closer to the target subcooling value. If the refrigerant charge level was previously increased and the subcooling value is now closer to the target subcooling value, controller 105 may continue to increase the refrigerant charge level. Likewise, if the refrigerant charge level was previously decreased and the subcooling value is now closer to the target subcooling value, controller 105 may continue to decrease the refrigerant charge level. However, if the refrigerant charge level was previously increased and the subcooling value is now further from the target subcooling value, controller 105 may begin decreasing the refrigerant charge level. If the refrigerant charge level was previously decreased and the subcooling value is now further from the target subcooling value, controller 105 may begin increasing the refrigerant charge level.
[0045] To assist controller 105 in determining whether to increase or decrease the refrigerant charge level, a liquidity sensor may be added to the liquid line. The liquidity sensor may be an optical or turbidity sensor which looks for bubbles through a side glass in the liquid line. The absence of bubbles indicates there is sufficient refrigerant charge level in the liquid line. Thus, if the liquidity sensor finds the refrigerant is sufficiently free of bubbles, controller 105 may always decrease the refrigerant charge level.
[0046] With reference to FIG. 6, depicted is an alternate method 600 which controller 105 may perform to control the refrigerant charge level. Method 600 uses EER
(Energy Efficiency Ratio) to determine whether the refrigerant charge level should be changed.
EER is the ratio of energy expended to the amount of heating or cooling performed. The EER is an indicator of the effectiveness of the system 100 or 300. The higher the EER, the more efficiently the system is operating.
(Energy Efficiency Ratio) to determine whether the refrigerant charge level should be changed.
EER is the ratio of energy expended to the amount of heating or cooling performed. The EER is an indicator of the effectiveness of the system 100 or 300. The higher the EER, the more efficiently the system is operating.
[0047] In a compressor driven by an inverter, the amount of energy being expended can be obtained from the inverter driving the compressor. In a compressor not driven by an inverter, the amount of energy being expended can be measured from compressor current, compressor voltage, and phase angle at the compressor. The amount of heating or cooling performed is measured by a heat transferring capacity of the HVAC system. The heat transferring capacity may be the sensible capacity of the system, regardless of whether the system is heating or cooling. If the system is cooling, the heat transferring capacity may alternately be the latent capacity of the system, or the total of the sensible and latent capacities of the system.
[0048] The sensible capacity may be expressed as the product of indoor airflow rate, a constant, and rise in air temperature. The sensible capacity may therefore be calculated from the indoor airflow, return air temperature, and supply air temperature. The return air is the volume of air returned to indoor unit 102 from the structure. The supply air is the volume of air passed over indoor heat exchanger 118 and discharged to the structure. Indoor unit 102 may have a return air temperature sensor where it receives the return air and a supply air temperature sensor where it discharges the supply air.
[0049] The latent capacity may be predicted from lab test data and present conditions, such as indoor temperature, humidity, and indoor airflow. Alternately, latent capacity may be predicted from the rate of condensate (water vapor that is condensed on the surface of the evaporator).
[0050] Controller 105 may have a memory which stores target EERs for a given load on the HVAC system. The target EERs represent an ideal EER when the refrigerant charge level is optimized for a given load. These target EERs may be determined during testing or simulation of the HVAC system.
[0051] At 602, controller 105 may measure the energy used by the compressor and sensible capacity of the HVAC system. At 604, controller 105 may calculate the EER from the energy used and sensible capacity. At 606, controller 105 may compare the EER to the target EER for the present operating load. At 608, controller 105 may operate valves 128A, 128B, and 128C on charge control apparatus 101 or charge control apparatus 103 to adjust the refrigerant charge level. 608 may be performed identically to 508, except with the difference between the EER and target EER used in place of the difference between the subcooling value and target subcooling value.
[0052] The size of reservoirs 126 and 302 may vary depending on the particular HVAC
system. A reservoir should be large enough to accommodate the difference between the largest and smallest optimal refrigerant charge levels for the different operating loads of the system.
system. A reservoir should be large enough to accommodate the difference between the largest and smallest optimal refrigerant charge levels for the different operating loads of the system.
[0053] It is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features.
Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of various embodiments.
Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of various embodiments.
Claims (15)
1. An apparatus for adjusting refrigerant charge level, the apparatus comprising:
a reservoir;
a reservoir line connecting the reservoir and a liquid line, the liquid line connecting an indoor heat exchanger and an outdoor heat exchanger, the reservoir line comprising a connection to the liquid line;
a reservoir valve on the reservoir line; and one or more side valves on the liquid line.
a reservoir;
a reservoir line connecting the reservoir and a liquid line, the liquid line connecting an indoor heat exchanger and an outdoor heat exchanger, the reservoir line comprising a connection to the liquid line;
a reservoir valve on the reservoir line; and one or more side valves on the liquid line.
2. The apparatus of Claim 1, wherein the one or more side valves comprises an indoor side valve on the liquid line between the indoor heat exchanger and the connection to the reservoir line.
3. The apparatus of Claim 1, wherein the one or more side valves comprises an outdoor side valve on the liquid line between the outdoor heat exchanger and the connection to the reservoir line.
4. The apparatus of Claim 1, wherein the one or more side valves comprises:
an indoor side valve on the liquid line between the indoor heat exchanger and the connection to the reservoir line; and an outdoor side valve on the liquid line between the outdoor heat exchanger and the connection to the reservoir line.
an indoor side valve on the liquid line between the indoor heat exchanger and the connection to the reservoir line; and an outdoor side valve on the liquid line between the outdoor heat exchanger and the connection to the reservoir line.
5. The apparatus of Claim 1, wherein the reservoir valve and the one or more side valves each comprise a solenoid valve.
6. The apparatus of Claim 1, wherein the reservoir is above the liquid line.
7. The apparatus of Claim 1, wherein:
a suction line passes through the reservoir; and the suction line is connected to a compressor.
a suction line passes through the reservoir; and the suction line is connected to a compressor.
8. A method for adjusting refrigerant charge level, the method comprising:
calculating an indicator of effectiveness of a refrigerant-using system;
comparing the indicator to a target indicator of effectiveness; and adjusting a refrigerant charge level to reduce the difference between the indicator and the target indicator.
calculating an indicator of effectiveness of a refrigerant-using system;
comparing the indicator to a target indicator of effectiveness; and adjusting a refrigerant charge level to reduce the difference between the indicator and the target indicator.
9. The method of Claim 8, wherein adjusting the refrigerant charge level comprises opening or closing a solenoid valve.
10. The method of Claim 8, wherein:
the indicator comprises a subcooling value;
the target indicator comprises a subcooling value; and calculating the indicator comprises measuring a liquid temperature and liquid pressure.
the indicator comprises a subcooling value;
the target indicator comprises a subcooling value; and calculating the indicator comprises measuring a liquid temperature and liquid pressure.
11. The method of Claim 8, wherein:
the indicator comprises an energy efficiency ratio;
the target indicator comprises an energy efficiency ratio; and calculating the indicator comprises:
measuring an energy usage of a compressor; and measuring a heat transferring capacity of the system.
the indicator comprises an energy efficiency ratio;
the target indicator comprises an energy efficiency ratio; and calculating the indicator comprises:
measuring an energy usage of a compressor; and measuring a heat transferring capacity of the system.
12. The method of Claim 11, wherein the heat transferring capacity comprises a sensible capacity of the system.
13. The method of Claim 12, wherein measuring the sensible capacity comprises measuring an indoor airflow, a return air temperature, and a supply air temperature.
14. The method of Claim 11, wherein the heat transferring capacity comprises a latent capacity of the system.
15. The method of Claim 11, wherein the heat transferring capacity comprises a total of:
a sensible capacity of the system; and a latent capacity of the system.
a sensible capacity of the system; and a latent capacity of the system.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14/221,702 US20150267951A1 (en) | 2014-03-21 | 2014-03-21 | Variable refrigerant charge control |
| US14/221,702 | 2014-03-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2885755A1 true CA2885755A1 (en) | 2015-09-21 |
Family
ID=54141757
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2885755A Abandoned CA2885755A1 (en) | 2014-03-21 | 2015-03-19 | Variable refrigerant charge control |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US20150267951A1 (en) |
| CA (1) | CA2885755A1 (en) |
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| CN107923680B (en) * | 2015-08-28 | 2020-06-30 | 三菱电机株式会社 | Refrigeration cycle device |
| US10830515B2 (en) * | 2015-10-21 | 2020-11-10 | Mitsubishi Electric Research Laboratories, Inc. | System and method for controlling refrigerant in vapor compression system |
| US10794621B2 (en) * | 2016-11-18 | 2020-10-06 | Lg Electronics Inc. | Air conditoner and method for controlling an air conditioner |
| DE102017206547A1 (en) * | 2017-04-19 | 2018-10-25 | Robert Bosch Gmbh | Method for filling a piping circuit of a heat pump with a refrigerant, container therefor and heat pump |
| CN108870803A (en) * | 2017-05-12 | 2018-11-23 | 开利公司 | Heat pump system and its control method |
| JP2019011899A (en) * | 2017-06-30 | 2019-01-24 | 株式会社富士通ゼネラル | Air conditioning device |
| CN207556037U (en) * | 2017-09-08 | 2018-06-29 | 开利公司 | Liquid storage device and with its heat pump system |
| WO2019064248A1 (en) * | 2017-09-30 | 2019-04-04 | York (Wuxi) Air Conditioning And Refrigeration Co., Ltd. | Heat pump unit and the control method thereof |
| CN108507207A (en) * | 2017-09-30 | 2018-09-07 | 约克（无锡）空调冷冻设备有限公司 | A kind of heat pump unit and its control method |
| CN108168167A (en) * | 2018-02-01 | 2018-06-15 | 青岛绿环工业设备有限公司 | A kind of refrigerant recovering purification filling all-in-one machine |
| US11022382B2 (en) | 2018-03-08 | 2021-06-01 | Johnson Controls Technology Company | System and method for heat exchanger of an HVAC and R system |
| WO2020053613A1 (en) | 2018-09-12 | 2020-03-19 | Carrier Corporation | Liquid receiver for heating, air conditioning and refrigeration system |
| CN109631434B (en) * | 2018-12-13 | 2021-08-20 | 广东美的制冷设备有限公司 | System and method for filling refrigerant into air conditioner outdoor unit, air conditioner outdoor unit and air conditioning system |
| US11435123B2 (en) * | 2018-12-19 | 2022-09-06 | Toromont Industries Ltd | Refrigeration system with transfer system |
| US11125481B2 (en) | 2019-09-23 | 2021-09-21 | Lennox Industries Inc. | Method and system for charge determination |
| WO2023056617A1 (en) * | 2021-10-09 | 2023-04-13 | Johnson Controls Tyco IP Holdings LLP | Systems and methods for controlling variable refrigerant flow systems using artificial intelligence |
| DE102022100918A1 (en) | 2022-01-17 | 2023-07-20 | Schaeffler Technologies AG & Co. KG | Active filling quantity control of automotive refrigerant systems |
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| US3903709A (en) * | 1974-01-02 | 1975-09-09 | Heil Quaker Corp | Refrigerant charging apparatus |
| US4030315A (en) * | 1975-09-02 | 1977-06-21 | Borg-Warner Corporation | Reverse cycle heat pump |
| KR890004867B1 (en) * | 1985-03-25 | 1989-11-30 | 마쯔시다덴기산교 가부시기가이샤 | Haet pump with a reservoir storing higher pressure refrigerante of non-azeotropic mixture |
| KR100221257B1 (en) * | 1991-05-24 | 1999-09-15 | 피터 로보트슨 하아트 | Air conditioning for humid climates |
| US5802860A (en) * | 1997-04-25 | 1998-09-08 | Tyler Refrigeration Corporation | Refrigeration system |
| JP3152187B2 (en) * | 1997-11-21 | 2001-04-03 | ダイキン工業株式会社 | Refrigeration apparatus and refrigerant charging method |
| US7721560B2 (en) * | 2004-07-20 | 2010-05-25 | Carpenter Frank K | Climate control and dehumidification system and method |
| JP4670329B2 (en) * | 2004-11-29 | 2011-04-13 | 三菱電機株式会社 | Refrigeration air conditioner, operation control method of refrigeration air conditioner, refrigerant amount control method of refrigeration air conditioner |
| SE529598C2 (en) * | 2006-02-01 | 2007-10-02 | Svenning Ericsson | Flow control of refrigerant |
| EP2000751B1 (en) * | 2006-03-27 | 2019-09-18 | Mitsubishi Electric Corporation | Refrigeration air conditioning device |
| US8961811B2 (en) * | 2010-04-15 | 2015-02-24 | E I Du Pont De Nemours And Company | Compositions comprising E-1,2-difluoroethylene and uses thereof |
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