US20220170673A1 - Heat Pump System Defrosting Operations - Google Patents
Heat Pump System Defrosting Operations Download PDFInfo
- Publication number
- US20220170673A1 US20220170673A1 US17/562,280 US202117562280A US2022170673A1 US 20220170673 A1 US20220170673 A1 US 20220170673A1 US 202117562280 A US202117562280 A US 202117562280A US 2022170673 A1 US2022170673 A1 US 2022170673A1
- Authority
- US
- United States
- Prior art keywords
- heat pump
- refrigerant
- pump system
- charge compensator
- isolation valve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000010257 thawing Methods 0.000 title description 11
- 239000003507 refrigerant Substances 0.000 claims abstract description 204
- 238000002955 isolation Methods 0.000 claims abstract description 151
- 238000010438 heat treatment Methods 0.000 claims abstract description 71
- 239000007788 liquid Substances 0.000 claims abstract description 71
- 238000001816 cooling Methods 0.000 claims abstract description 48
- 239000012530 fluid Substances 0.000 claims 2
- 238000000034 method Methods 0.000 description 24
- 230000008901 benefit Effects 0.000 description 5
- 230000004044 response Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 230000002457 bidirectional effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- 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
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control 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
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/39—Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator
-
- 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
- F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
- F25B47/02—Defrosting cycles
- F25B47/022—Defrosting cycles hot gas defrosting
- F25B47/025—Defrosting cycles hot gas defrosting by reversing 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
- 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
- F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
- F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
- F25D21/002—Defroster control
-
- 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
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/027—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means
- F25B2313/02741—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using one four-way valve
-
- 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
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/031—Sensor arrangements
- F25B2313/0314—Temperature sensors near the indoor heat exchanger
-
- 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
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/031—Sensor arrangements
- F25B2313/0315—Temperature sensors near the outdoor heat exchanger
-
- 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
- F25B2400/04—Refrigeration circuit bypassing means
- F25B2400/0409—Refrigeration circuit bypassing means for the evaporator
-
- 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
- F25B2400/04—Refrigeration circuit bypassing means
- F25B2400/0411—Refrigeration circuit bypassing means for the expansion valve or capillary tube
-
- 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
- F25B2400/13—Economisers
-
- 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
- F25B2600/2501—Bypass valves
Definitions
- the present disclosure relates generally to heat pump systems, and more particularly to improved defrosting operations of heat pump systems.
- Heat pump systems typically operate in a heating mode and a cooling mode.
- the outdoor coil of a heat pump system When operating in a cooling mode to cool a particular space, the outdoor coil of a heat pump system operates as a condenser that dissipates heat outdoors.
- the outdoor coil of a heat pump system When the operating in a heating mode to heat a particular space, the outdoor coil of a heat pump system operates as an evaporator.
- frost may form on the outdoor coil during heating mode operations, which may result in inefficient operations of the heat pump system.
- the heat pump system typically interrupts a heating mode operation and temporarily operates in a cooling mode that is generally referred to as a defrost mode to distinguish it from typical cooling mode operations performed for the purpose of cooling a particular space.
- refrigerant that is removed from circulation and stored in a charge compensator during the heating mode operation is returned back to circulation.
- refrigerant that is removed from circulation and stored in the charge compensator during the heating mode operation is also returned back to circulation.
- the refrigerant that is returned to circulation from the charge compensator during a defrost operation may result in the defrost mode operation lasting longer than desired. For example, a longer defrost operation may be undesirable because of the longer interruption of a heating mode operation, which is a normal mode of operation of the heat pump system but for the need to defrost the outdoor coil. Thus a solution that results in shorter defrost operations of heat pump systems may be desirable.
- a heat pump system including a charge compensator having a liquid line port for an inflow of a refrigerant into the charge compensator and for an outflow of the refrigerant from the charge compensator.
- the heat pump system further includes an isolation valve configured to control flows of the refrigerant to and from the charge compensator through a liquid line piping of the heat pump system based on whether the heat pump system is operating in a cooling mode, a defrost mode, or a heating mode, where the liquid line port is fluidly coupled to the liquid line piping of the heat pump system.
- the charge compensator includes a liquid line port for an inflow of the refrigerant into the charge compensator and for an outflow of the refrigerant from the charge compensator.
- the method further includes controlling, by the control unit, the isolation valve to prevent the refrigerant from flowing from the charge compensator to a system refrigerant circulation piping of the heat pump system through a liquid line piping of the heat pump system during a defrost mode operation of the heat pump system.
- the charge compensator includes a liquid line port that is coupled to the liquid line piping.
- the method further includes storing, by the charge compensator, the refrigerant and closing, by the isolation valve, the flow path to prevent the refrigerant stored in the charge compensator from flowing, during a defrost mode operation of the heat pump system, from the charge compensator to the system refrigerant circulation piping through the liquid line piping.
- FIG. 1 illustrates a heat pump system including an isolation valve according to an example embodiment
- FIG. 2 illustrates the heat pump system of FIG. 1 configured for a defrost mode operation according to an example embodiment
- FIG. 3 illustrates the heat pump system of FIG. 1 configured for a cooling mode operation according to an example embodiment
- FIG. 4 illustrates a heat pump system including an isolation valve according to another example embodiment
- FIG. 5 illustrates a heat pump system including an isolation valve according to another example embodiment
- FIG. 6 illustrates the heat pump system of FIG. 5 configured for a defrost mode operation according to an example embodiment
- FIG. 7 illustrates the heat pump system of FIG. 5 configured for a cooling mode operation according to an example embodiment
- FIG. 8 illustrates a heat pump system including an isolation valve according to another example embodiment
- FIG. 9 illustrates the heat pump system of FIG. 8 configured for a defrost mode operation according to an example embodiment
- FIG. 10 illustrates the heat pump system of FIG. 8 configured for a cooling mode operation according to an example embodiment
- FIG. 11 illustrates a method of operating a heat pump system that includes an isolation valve according to an example embodiment
- FIG. 12 illustrates a method of operating a heat pump system that includes an isolation valve according to another example embodiment.
- an isolation valve is located along a refrigerant line connecting the charge compensator to the liquid line of a heat pump system to control the flow of refrigerant into and out of the charge compensator of the heat pump system based on the mode of operation of the heat pump system.
- the charge compensator typically stores extra refrigerant in during heating mode operations and returns the stored refrigerant back into circulation for the cooling mode operations as readily understood by those of ordinary skill in the art with the benefit of this disclosure.
- the isolation valve is open, allowing refrigerant to flow out of the charge compensator into circulation.
- the isolation valve is closed, thereby isolating the refrigerant in the charge compensator from combining with the refrigerant in circulation in the rest of the system. Isolating the charge compensator during defrost mode operations prevents the refrigerant in the charge compensator entering circulation through the heat pump system, which allows for higher discharge temperature of gas refrigerant leaving the compressor of the heat pump system resulting in faster defrosting of the outdoor coil.
- a relief valve (e.g., an in-line relief valve) may be placed in parallel with the isolation valve to prevent excessive pressure from building in the charge compensator when the isolation valve is preventing refrigerant flow from the charge compensator into system circulation.
- the relief valve may be a spring loaded spring valve or another pressure-actuated valve that opens to relieve pressure when the pressure in the charge compensator reaches or exceeds a safety threshold and stays closed prior to the pressure reaching or exceeding the safety threshold.
- the isolation valve may be controlled to release some of the refrigerant stored in the charge compensator into the system circulation during defrost mode operations instead of fully isolating the charge compensator during entire defrost mode operations.
- FIG. 1 illustrates a heat pump system 100 including an isolation valve 120 according to an example embodiment.
- the heat pump system 100 includes an indoor coil 102 , an outdoor coil 104 , and the isolation valve 120 .
- the heat pump system 100 may include a compressor 106 , a reversing valve 108 , and a charge compensator 110 .
- the heat pump system 100 may also include expansion devices 112 , 114 , which could be thermal expansion devices or other types of expansion devices.
- the expansion devices 112 , 114 may be electronically or thermally activated.
- a control unit 116 may control the operation modes of the heat pump system 100 .
- the control unit 116 may control the reversing valve 108 to control the operation modes of the heat pump system 100 by controlling the direction of system refrigerant flow through the system refrigerant circulation piping of the heat pump system 100 .
- the control unit 116 may control the reversing valve 108 such that the system refrigerant circulates through the system refrigerant circulation piping in the directions shown by the solid arrows, such as the arrow 132 .
- the system refrigerant circulation piping may include refrigerant pipes 122 , 124 , 130 and other pipes and connections between the reversing valve 108 and the indoor coil 102 , the compressor 106 , and the charge compensator 110 as well as between the outdoor coil 104 and the charge compensator 110 .
- the control unit 116 may configure the reversing valve 108 such that system (i.e., circulating) refrigerant flows from the outdoor coil 104 to the suction port of the compressor 106 through the reversing valve 108 and through the charge compensator 110 (i.e., through the flow path 136 ) and such that the system/circulating refrigerant flows from the discharge port of the compressor 106 to the indoor coil 102 through the reversing valve 108 .
- the circulation of the system refrigerant through the system refrigerant circulation piping is completed by the flow of the system refrigerant from the indoor coil 102 to the outdoor coil 104 through the expansion devices 112 , 114 .
- the outdoor coil 104 operates as an evaporator
- the indoor coil 102 operates as a condenser.
- the expansion device 112 throttles the refrigerant flow on the lower pressure side from a higher pressure to a lower pressure while the expansion device 114 acts as a flow passage.
- the expansion device 114 throttles the refrigerant flow while the expansion device 112 acts as a flow passage.
- the isolation valve 120 is located to control flows of refrigerant through a liquid line piping of the heat pump system 100 .
- the isolation valve 120 may be a solenoid valve or another type of valve as can be readily understood by those of ordinary skill in the art with the benefit of this disclosure.
- the isolation valve 120 may provide a single flow path that, when open, allows the flow of refrigerant in both directions depending on the mode of operation of the heat pump system 100 .
- the isolation valve 120 may provide two single direction flow paths or bidirectional that are open or closed under the control of the control unit 116 .
- the liquid line piping may include pipe sections 126 , 128 and is coupled to and between the charge compensator 110 and the refrigerant pipe 130 .
- the isolation valve 120 may be in-line with or otherwise coupled to the liquid line piping to control refrigerant flows through the liquid line piping from and to the charge compensator 110 and the refrigerant pipe 130 .
- the pipe section 128 of the liquid line piping may be fluidly coupled to a liquid line port 118 of the charge compensator 110
- the pipe section 126 of the liquid line piping may be fluidly coupled to the refrigerant pipe 130 of the system refrigerant circulation piping.
- control unit 116 may control the isolation valve 120 to control flows of refrigerant from and to the charge compensator 110 and the refrigerant pipe 130 through the liquid line piping including pipe sections 126 , 128 .
- the control unit 116 may send a control signal via an electrical connection 138 to the isolation valve 120 (e.g., a solenoid valve) to control the state of the isolation valve 120 .
- the control unit 116 may control the isolation valve 120 to open or keep open a flow path for refrigerant to flow from the refrigerant pipe 130 to the charge compensator 110 through the liquid line piping including pipe sections 126 , 128 .
- some of the system refrigerant flowing in the system refrigerant circulation piping may flow into the charge compensator 110 through the liquid line piping and the isolation valve 120 as illustrated by the dotted arrow 134 .
- the control unit 116 may control the isolation valve 120 to allow the flow of refrigerant to the charge compensator 110 through the liquid line piping until the charge compensator 110 is full or at a certain fill level.
- the control unit 116 may control the isolation valve 120 such that the isolation valve 120 is open to allow the refrigerant to flow to the charge compensator 110 through the isolation valve 120 .
- the control unit 116 may control the isolation valve 120 (e.g., close the isolation valve 120 ) to prevent more refrigerant from flowing to the charge compensator 110 through the liquid line piping.
- the control unit 116 may control the isolation valve 120 to close the flow path to the charge compensator 110 through the liquid line piping after a period of time following the start of a heating mode operation. The period of time that the control unit 116 waits before controlling the isolation valve 120 to stop the flow to the charge compensator 110 may depend on the system capacity, the size of the charge compensator 110 , etc.
- the isolation valve 120 may remain closed for the duration of the particular heating operation.
- control unit 116 may control the isolation valve 120 to keep the flow path through the liquid line piping open until the operation mode of the heat pump system 100 is changed or needs to be changed to a defrost mode.
- control unit 116 may determine that a defrost mode operation needs to be performed to remove frost from the outdoor coil 104 , for example, based on an input from a frost thermostat at the outdoor coil 104 .
- control unit 116 may control the reversing valve 108 to change the operation mode of the heat pump system 100 to a defrost mode and control the isolation valve 120 to prevent the refrigerant stored in the charge compensator 110 during a heating mode operation from flowing to the refrigerant pipe 130 through the liquid line piping.
- control unit 116 may send a control signal to the isolation valve 120 to close the isolation valve 120 or otherwise close a flow path from the charge compensator 110 to the refrigerant pipe 130 through the liquid line piping.
- the control unit 116 may control the isolation valve 120 to keep the refrigerant flow path between the refrigerant pipe 130 and the charge compensator 110 through the liquid line piping closed.
- the control unit 116 may control the isolation valve 120 to open the refrigerant flow path from the refrigerant pipe 130 to the charge compensator 110 through the liquid line piping if the heat pump system 100 returns to a heating mode operation following the defrost mode operation.
- control unit 116 may control the isolation valve 120 to allow the refrigerant that is stored in the charge compensator 110 during a heating mode operation to return to the refrigerant pipe 130 through the liquid line piping by flowing in the opposite direction to the dotted arrow 134 .
- control unit 116 may control the reversing valve 108 to change the operation mode of the heat pump system 100 to a cooling mode and control the isolation valve 120 to allow the refrigerant stored in the charge compensator 110 to flow to the refrigerant pipe 130 through the liquid line piping.
- the control unit 116 may control the isolation valve 120 to keep the refrigerant flow path through the liquid line piping between the charge compensator 110 and the refrigerant pipe 130 open through the entire cooling mode operation.
- control unit 116 may control the reversing valve 108 to change the operation mode of the heat pump system 100 at substantially the same time (e.g., 10 seconds, 5 seconds, 100 milliseconds, etc. before or after) that the control unit 116 controls the isolation valve 120 to open or close the flow path of refrigerant through the liquid line piping.
- control unit 116 may include a microprocessor or a microcontroller, one or more memory devices, and other components and may send respective control signals to the reversing valve 108 and the isolation valve 120 .
- a microcontroller of the control unit 116 may execute a software code stored in a memory device of the control unit 116 to perform some of the operation described herein with respect to the control unit 116 .
- the heat pump system 100 may include other components than shown in FIG. 1 without departing from the scope of this disclosure.
- the heat pump system 100 may include a filter-drier between the expansion devices 112 , 114 .
- a filter-drier may be in-line with the system refrigerant circulation piping between the connection point of the pipe section 126 to the refrigerant pipe 130 and the expansion device 112 .
- some of the components of the heat pump system 100 may be integrated into a single component without departing from the scope of this disclosure.
- the isolation valve 120 may be integrated into the charge compensator 110 .
- FIG. 2 illustrates the heat pump system 100 of FIG. 1 configured for a defrost mode operation according to an example embodiment.
- the reversing valve 108 is controlled by control unit 116 to operate in a defrost mode such that the system refrigerant flows through the system refrigerant circulation piping in directions shown by the solid arrows such as the solid arrow 204 .
- the system refrigerant flows from the indoor coil 102 to the suction port of the compressor 106 through the reversing valve 108 and from the discharge port of the compressor 106 to the outdoor coil 104 through the reversing valve 108 and the charge compensator 110 .
- the configuration of the reversing valve 108 as shown in FIG. 2 provides a flow path for the system refrigerant to flow from the indoor coil 102 to the outdoor coil 104 through the reversing valve 108 and through the charge compensator 110 (i.e., through the flow path 136 ).
- the outdoor coil 104 operates as a condenser, which allows the outdoor coil 104 to dissipate heat to defrost the outdoor coil 104 .
- the heat pump system 100 may be configured to operate in the defrost mode in response to a frost build-up on the outdoor coil 104 during a heating mode operation of the heat pump system 100 .
- the control unit 116 may determine that the heat pump system 100 needs to operate in a defrost mode operation to remove frost from the outdoor coil 104 , for example, based on an input from a temperature sensor at the outdoor coil 104 .
- the control unit 116 may determine the need to operate in a defrost mode using other means as can be readily understood by those of ordinary skill in the art with the benefit of this disclosure.
- the control unit 116 may be configured to periodically interrupt heating mode operations of the heat pump system 100 and to operate the heat pump system 100 in a defrost mode to remove frost that may accumulate on the outdoor coil 104 .
- the isolation valve 120 is closed or otherwise prevents the flow of refrigerant from the charge compensator 110 to the system refrigerant circulation piping that includes the refrigerant pipe 130 .
- the control unit 116 may maintain the flow path closed using the isolation valve 120 when the heat pump system 100 enters the defrost mode.
- control unit 116 may close the flow path using the isolation valve 120 when the heat pump system 100 enters the defrost mode. By preventing the return of refrigerant from the charge compensator 110 into system circulation during defrost mode operations, a higher discharge temperature of the refrigerant leaving the compressor 106 may be achieved, resulting in faster defrosting of the outdoor coil 104 .
- the control unit 116 may configure the reversing valve 108 to operate the heat pump system 100 back in a heating mode. For example, the control unit 116 may operate the heat pump system 100 in the defrost mode until the temperature of the outdoor coil reaches a particular temperature (e.g., above 55° F.) or may operate in the defrost mode for a time period (dependent on the particular system) that would allow adequate defrosting. Immediately before, at the same time, or after configuring the reversing valve 108 to operate in a heating mode from the defrost mode operation, the control unit 116 may control the isolation valve 120 such that the refrigerant flow path through the liquid line piping is open. Alternatively, the control unit 116 may control the isolation valve 120 to keep the refrigerant flow path through the liquid line piping closed during the heating mode operation that is subsequent to the defrost mode operation.
- a particular temperature e.g., above 55° F.
- the control unit 116 may control the isolation valve 120 such that the refrig
- the control unit 116 may control the isolation valve 120 such that, instead of preventing the flow of the refrigerant stored in the charge compensator 110 to the system refrigerant circulation piping, some of the refrigerant flows to the system refrigerant circulation piping.
- the control unit 116 may control the isolation valve 120 for a duration of time at the start of the defrost mode of operation. The duration of time may vary depending on the system capacity, the capacity of the charge compensator 110 , etc.
- FIG. 3 illustrates the heat pump system 100 of FIG. 1 configured for a cooling mode operation according to an example embodiment.
- the cooling mode configuration of the reversing valve 108 as shown in FIG. 3 is the same as the defrost mode configuration of the reversing valve 108 shown in FIG. 2 .
- the system refrigerant flows from the indoor coil 102 to the suction port of the compressor 106 through the reversing valve 108 and from the discharge port of the compressor 106 to the outdoor coil 104 through the reversing valve 108 and the charge compensator 110 .
- FIG. 3 illustrates the heat pump system 100 of FIG. 1 configured for a cooling mode operation according to an example embodiment.
- the cooling mode configuration of the reversing valve 108 as shown in FIG. 3 is the same as the defrost mode configuration of the reversing valve 108 shown in FIG. 2 .
- the system refrigerant flows from the indoor coil 102 to the suction port of the compressor 106 through the reversing valve 108 and
- the reversing valve 108 provides a flow path for the system refrigerant to flow from the indoor coil 102 to the outdoor coil 104 through the reversing valve 108 and through the charge compensator 110 (i.e., through the flow path 136 ).
- the isolation valve 120 is open or otherwise allows the flow of refrigerant from the charge compensator 110 to the system refrigerant circulation piping as shown by the arrow 302 . If the isolation valve 120 was configured to allow refrigerant flow from the charge compensator 110 through the liquid line piping during an immediately prior heating mode operation, the control unit 116 may maintain the configuration of the isolation valve 120 when the heat pump system 100 enters the cooling mode.
- control unit 116 may control the isolation valve 120 to allow refrigerant flow from the charge compensator 110 to the refrigerant pipe 130 through the liquid line piping when the heat pump system 100 enters the cooling mode.
- the isolation valve 120 allows for more efficient defrosting operations without disrupting the regular cooling and heating mode operations of the heat pump system 100 .
- the isolation valve 120 may be fluidly coupled to the system refrigerant circulation piping at a different location than the refrigerant pipe 130 without departing from the scope of this disclosure.
- FIG. 4 illustrates a heat pump system 400 including the isolation valve 120 according to another example embodiment.
- the heat pump system 400 includes the same components and operates in substantially the same manner as the heat pump system 100 .
- the heat pump system 400 includes the indoor coil 102 , the outdoor coil 104 , the compressor 106 , the reversing valve 108 , the charge compensator 110 , the expansion devices 112 , 114 , and the isolation valve 120 .
- the heat pump system 400 includes a relief valve 402 .
- the heat pump system 400 may operate in a heating mode, a defrost mode, and a cooling mode in the same manner as described with respect to the heat pump system 100 .
- the control unit 116 may configure the reversing valve 108 such that system (i.e., circulating) refrigerant flows from the indoor coil 102 to the suction port of the compressor 106 through the reversing valve 108 and from the discharge port of the compressor 106 to the outdoor coil 104 through the reversing valve 108 and the charge compensator 110 .
- system i.e., circulating
- the outdoor coil 104 operates as a condenser, which allows the outdoor coil 104 to dissipate heat to remove frost from the outdoor coil 104 that might have accumulated, for example, during a heating mode operation.
- the isolation valve 120 operates in the same manner as described above with respect to the heat pump system 100 .
- the isolation valve 120 is closed or otherwise prevents refrigerant stored in the charge compensator 110 from flowing from the charge compensator 110 to the system refrigerant circulation piping through the liquid line piping that includes the pipes 126 , 128 .
- the isolation valve 120 is open or otherwise allows refrigerant stored in the charge compensator 110 to flow from the charge compensator 110 to the system refrigerant circulation piping through the liquid line piping.
- the isolation valve 120 may be open or otherwise allow some of the system refrigerant to flow to the charge compensator 110 through the liquid line piping.
- the isolation valve 120 may be open during all heating mode operations.
- the isolation valve 120 may be open during a heating mode operation and may then be closed when the heat pump system 400 switches to a defrost mode operation.
- the isolation valve 120 may remain closed for the duration of the subsequent heating mode operation.
- the isolation valve 120 may be opened or otherwise allow some of the system refrigerant to flow to the charge compensator 110 through the liquid line piping.
- the isolation valve 120 may be closed by the control unit 116 when the charge compensator 110 fills up or is filled by refrigerant to a particular fill level.
- the relief valve 402 may be placed in parallel with the isolation valve 120 to provide a bypass flow path to protect against excessive pressure build up in the charge compensator 110 when the isolation valve 120 is closed or otherwise prevents the flow of refrigerant from the charge compensator 110 to the refrigerant pipe 130 .
- the relief valve 402 may be a spring loaded spring valve or another type of pressure-actuated valve that opens to relieve pressure in the charge compensator 110 when the pressure in the charge compensator 110 or across the relief valve 402 reaches or exceeds a threshold. The relief valve 402 may close when the pressure in the charge compensator 110 or across the relief valve 402 is below threshold.
- the relief valve 402 may be an in-line relief valve that open to provide a refrigerant flow path through the relief valve 402 in a direction shown by the arrow 404 when the pressure in the charge compensator 110 reaches or exceeds a threshold or when the pressure across the relief valve 402 reaches or exceeds a threshold.
- the refrigerant flow path through the relief valve 402 allows some of the refrigerant stored in the charge compensator 110 to flow to the refrigerant pipe 130 , resulting in a decreased pressure inside the charge compensator 110 .
- the flow path through the relief valve 402 closes when the pressure in the charge compensator 110 or the pressure across the relief valve 402 decreases, for example, to below a threshold level.
- the pressure threshold levels for opening the flow path through the relief valve 402 in the direction shown by the arrow 404 may depend on the system capacity, the capacity of the charge compensator 110 , etc. as can be readily understood by those of ordinary skill in the art with the benefit of this disclosure.
- the isolation valve 120 allows for more efficient defrosting operations without disrupting the regular cooling and heating mode operations of the heat pump system 400 .
- the relief valve 402 may provide improved system performance by reducing the risk of system malfunction.
- the relief valve 402 may be coupled in a different piping configuration than shown without departing from the scope of this disclosure.
- the isolation valve 120 and the relief valve 402 may be fluidly coupled to the refrigerant pipe 130 using separate pipes instead of the pipe section 126 without departing from the scope of this disclosure.
- the heat pump system 400 may include other components than shown in FIG. 4 without departing from the scope of this disclosure.
- the heat pump system 400 may include a filter-drier between the expansion devices 112 , 114 .
- some of the components of the heat pump system 400 may be integrated into a single component without departing from the scope of this disclosure.
- the isolation valve 120 may be integrated into the charge compensator 110 .
- FIGS. 5-7 illustrate a heat pump system 500 including an isolation valve 502 according to another example embodiment.
- the heat pump system 500 is configured for heating mode operations.
- the heat pump system 500 is configured for defrost mode operations.
- the heat pump system 500 is configured for cooling mode operations.
- the heat pump system 500 includes components described above with respect to the heat pump system 100 . To illustrate, the heat pump system 500 includes the indoor coil 102 , the outdoor coil 104 , the compressor 106 , the reversing valve 108 , the charge compensator 110 , the expansion devices 112 , 114
- the control unit 116 controls the reversing valve 108 to configure the heat pump system 500 in a heating mode, a cooling mode, and a defrost mode in the same manner as described above with respect to the heat pump system 100 .
- the heat pump system 500 includes the isolation valve 502 that is temperature actuated instead of being controlled by the control unit 116 .
- the heat pump system 500 may include a temperature sensor 504 (e.g., a temperature sensing bulb) that is coupled to the isolation valve 502 .
- the temperature sensor 504 may be positioned to sense the temperature of the system refrigerant flowing between the indoor coil 102 and the reversing valve 108 as shown in FIG. 1 .
- the temperature sensor 504 be positioned at a different location, such as the location 506 or 508 , without departing from the scope of this disclosure.
- the isolation valve 502 may operate as a typical temperature actuated valve that responds to an input corresponding to a temperature that is below or above a threshold temperature.
- the isolation valve 502 may be opened or closed in response to an input provided from the temperature sensor 504 .
- the temperature sensor 504 may be configured to provide a frost indicator input to the isolation valve 502 when the system refrigerant temperature, as sensed by the temperature sensor 504 , reaches or decreases to below a frost threshold temperature (e.g., 35° F.) that is indicative of a frost accumulation on the outdoor coil 104 .
- a frost threshold temperature e.g. 35° F.
- the temperature sensor 504 may be configured to provide the frost indicator input to the isolation valve 502 when the temperature of the system refrigerant, as sensed by the temperature sensor 504 , corresponds to a frost condition that would trigger the control unit 116 to configure the reversing valve 108 for a defrost mode operation of the heat pump system 500 .
- the isolation valve 502 may close or otherwise prevent the flow of refrigerant from the charge compensator 110 to the refrigerant pipe 130 through the liquid line piping.
- the isolation valve 502 may open or otherwise allow the flow of refrigerant from the charge compensator 110 to the refrigerant pipe 130 through the liquid line piping.
- the temperature sensor 504 may be configured to stop providing the frost indicator input or to provide another input to the isolation valve 502 when the temperature of the system refrigerant, as sensed by the temperature sensor 504 , corresponds to a condition indicative of the control unit 116 operating the heat pump system 500 in a mode (heating or cooling mode) other than the defrost mode.
- the system 500 may include an air temperature sensor 510 (e.g., a temperature sensing bulb) that is located close to the outdoor coil 104 .
- the air temperature sensor 510 may be located to sense air temperature at the outdoor coil 104 without being directedly attached to the outdoor coil 104 .
- the air temperature sensor 510 may be located upstream of the outdoor coil 104 such that the air temperature sensed by the temperature sensor 504 is not meaningfully affected by air flow over the outdoor coil 104 .
- the air temperature sensor 510 may be located at a different relative position with respect to the outdoor coil 104 (e.g., downstream of the outdoor coil 104 ), where the air temperature sensed by the air temperature sensor 504 may be meaningfully affected by air flow over the outdoor coil 104 .
- the temperature sensor 504 may even be located inside an outdoor unit that includes the outdoor coil 104 without being directly attached to the outdoor coil 104 itself.
- the temperature sensor 510 may be at a different location than shown in FIG. 5 or described above, without departing from the scope of this disclosure.
- the isolation valve 502 may operate based on an input provided from the temperature sensor 510 in a similar manner as described with respect to the temperature sensor 504 .
- the isolation valve 502 may operate as a typical temperature actuated valve that responds to the input from the temperature sensor 510 corresponding to a temperature that is below or above a threshold air temperature.
- the isolation valve 502 may be opened or closed in response to the input provided from the temperature sensor 510 .
- the temperature sensor 510 may be configured to provide a valve control input to the isolation valve 502 that indicates whether the air temperature, as sensed by the air temperature sensor 510 , is at, below, and/or above the threshold air temperature.
- the valve control input from the air temperature sensor 510 may indicate that the isolation valve should be open.
- the valve control input from the air temperature sensor 510 may indicate that the isolation valve should be closed.
- the isolation valve 502 may open (or otherwise allow refrigerant flow between the charge compensator 110 and the refrigerant pipe 130 through the liquid line piping) or close (or otherwise prevent the flow of refrigerant from the charge compensator 110 to the refrigerant pipe 130 through the liquid line piping) depending on the valve control input from the temperature sensor 510 .
- the threshold air temperature may be within a temperature range of 35° F. to 50° F. (e.g., a temperature in 45° F.) when the air temperature sensor 510 is on the upstream side of the outdoor coil 104 .
- the temperature range by be slightly different (e.g., lower values at both end limits) when the air temperature sensor 510 is on the downstream side of the outdoor coil 104 where the air temperature sensed by the air temperature sensor 510 may be affected by air flow passing over the outdoor coil 104 .
- the upper limit of the temperature range may be set such that, when the system 500 starts operating in the heat mode, some of the refrigerant circulating in the system 500 can enter the charge compensator 110 through the isolation valve 502 before the isolation valve 502 is closed for the duration of the heating mode operation.
- the threshold air temperature for opening the isolation valve 502 may be different from the threshold air temperature for closing the isolation valve 502 .
- the isolation valve 502 allows for more efficient defrosting operations without disrupting regular cooling and heating mode operations of the heat pump system 500 .
- the air temperature sensor 510 may be used in conjunction with the temperature sensor 504 to control the opening and closing of the isolation valve 502 .
- particular temperature/condition related indications from both sensors 504 , 510 may be required to open and/or close the isolation valve 502 .
- a temperature/condition related indication from one of the two sensors 504 , 510 may be used to open and/or close the isolation valve 502 .
- the heat pump system 500 may include the relief valve 402 shown in FIG. 4 without departing from the scope of this disclosure.
- the relief valve 402 may be integrated in the heat pump system 500 in the same or similar configuration as in the heat pump system 400 .
- the heat pump system 500 may include other components than shown in FIG. 5 without departing from the scope of this disclosure.
- the heat pump system 500 may include a filter-drier between the expansion devices 112 , 114 .
- some of the components of the heat pump system 500 may be integrated into a single component without departing from the scope of this disclosure.
- the isolation valve 120 may be integrated into the charge compensator 110 .
- FIGS. 8-10 illustrate a heat pump system 800 including the isolation valve 120 according to another example embodiment.
- the heat pump system 800 is configured for heating mode operations.
- the heat pump system 800 is configured for defrost mode operations.
- the heat pump system 800 is configured for cooling mode operations.
- the heat pump system 800 includes components described above with respect to the heat pump system 100 .
- the heat pump system 800 includes the indoor coil 102 , the outdoor coil 104 , the compressor 106 , the reversing valve 108 , the charge compensator 110 , and the isolation valve 120 . the expansion devices 112 , 114 .
- the heat pump system 800 includes a bidirectional expansion device 802 (e.g., a thermal expansion device or another type of expansion device) instead of the expansion devices 112 , 114 .
- the pipe section 126 of the liquid line piping of the heat pump system 800 is fluidly coupled to the system refrigerant circulation piping at the refrigerant pipe 122 .
- the expansion device 802 may be electronically or thermally activated.
- the heat pump system 800 operates in heating modes, cooling modes, and defrost modes in the same manner as described above with respect to the heat pump system 100 .
- the control unit 116 may control the reversing valve 108 to control the mode of operation of the heat pump system 800 .
- the control unit 116 may also control the isolation valve 120 to control whether refrigerant flows to and from the charge compensator 110 during different operation modes of the heat pump system 800 in the same manner as described with respect to the heat pump system 100 .
- the heat pump system 800 may include the relief valve 402 shown in FIG. 4 .
- the relief valve 402 may be coupled in parallel with the isolation valve 120 to protect against excessive pressure build up in the charge compensator 110 when the isolation valve 120 is closed or otherwise prevents the flow of refrigerant from the charge compensator 110 to the refrigerant pipe 122 .
- the heat pump system 800 may include the isolation valve 502 of the heat pump system 500 instead of the isolation valve 120 shown in FIG. 8 .
- the heat pump system 800 may include the temperature sensor 504 that is coupled to the isolation valve 502 in the same manner as shown in FIG. 5 , and the isolation valve 502 may operate based on input(s) from the temperature sensor 504 as described above instead of operating under the control of the control unit 116 .
- the heat pump system 800 may include the relief valve 402 as well as the isolation valve 502 , where the relief valve 402 is coupled in a similar configuration as described above to protect against excessive pressure build up in the charge compensator 110 .
- the isolation valve 120 (alternatively the isolation valve 502 ) allows for more efficient defrosting operations without disrupting the regular cooling and heating mode operations of the heat pump system 800 .
- the relief valve 402 may provide improved system performance by reducing the risk of system malfunction.
- the heat pump system 800 may include other components than shown in FIG. 8 without departing from the scope of this disclosure.
- the heat pump system 800 may include a filter-drier between the expansion device 802 and the outdoor coil 104 .
- some of the components of the heat pump system 800 may be integrated into a single component without departing from the scope of this disclosure.
- the isolation valve 120 may be integrated into the charge compensator 110 .
- FIG. 11 illustrates a method 1100 of operating the heat pump system 100 , 400 , 500 , 800 that includes an isolation valve according to an example embodiment.
- the method 1100 includes, at step 1102 , opening, by the isolation valve 120 , 502 , a flow path for a refrigerant to flow, during a heating mode operation of the heat pump system 100 , 400 , 500 , 800 , from the system refrigerant circulation piping to the charge compensator 110 through the liquid line piping.
- the system refrigerant circulation piping may include refrigerant pipes 122 , 130 , etc.
- the liquid line piping may include the pipe sections 126 and 128 .
- the charge compensator 110 includes the liquid line port 118 that is coupled to the pipe sections 128 of the liquid line piping.
- the method 1100 may include storing, by the charge compensator 110 , the refrigerant that flows to the charge compensator 110 from the system refrigerant circulation piping to the charge compensator 110 through the liquid line piping.
- the charge compensator 110 may store the refrigerant until the charge compensator 110 is full or until the charge compensator 110 is filled to a particular level.
- the method 1100 may include closing, by the isolation valve 120 , 502 , the flow path to prevent the refrigerant stored in the charge compensator 110 from flowing, during a defrost mode operation of the heat pump system 100 , 400 , 500 , 800 , from the charge compensator 110 to the system refrigerant circulation piping through the liquid line piping.
- the flow path may be through the isolation valve 120 , 502 or may be controlled by the isolation valve 120 , 502 .
- the method 1100 may include other steps including opening or keeping open the flow path for the refrigerant stored in the charge compensator 110 to flow, during a cooling mode operation of the heat pump system, from the charge compensator 110 to the system refrigerant circulation piping through the liquid line piping.
- the method 1100 may also include providing, by the relief valve 402 , a bypass flow path for at least a portion of the refrigerant stored in the charge compensator 110 to flow from the charge compensator 110 to the system refrigerant circulation piping of the heat pump system if a pressure in the charge compensator 110 exceeds a threshold.
- the method 1100 may include more or fewer steps than described above without departing from the scope of this disclosure. In some example embodiments, some of the steps of the method 1100 may be performed in a different order than described above.
- FIG. 12 illustrates a method 1200 of operating a heat pump system 100 , 400 , 500 , 800 that includes an isolation valve according to another example embodiment.
- the method 1200 includes, at step 2102 , controlling, by the control unit 116 , the isolation valve 120 to open a flow path for a refrigerant to flow, during a heating mode operation of the heat pump system 100 , 400 , 500 , 800 , from the system refrigerant circulation piping to the charge compensator 110 through the liquid line piping.
- the system refrigerant circulation piping may include refrigerant pipes 122 , 130 , etc.
- the liquid line piping may include the pipe sections 126 and 128 .
- the charge compensator 110 includes the liquid line port 118 that is coupled to the pipe sections 128 of the liquid line piping.
- the method 1200 may include storing, by the charge compensator 110 , the refrigerant that flows to the charge compensator 110 from the system refrigerant circulation piping to the charge compensator 110 through the liquid line piping.
- the charge compensator 110 may store the refrigerant until the charge compensator 110 is full or until the charge compensator 110 is filled to a particular level.
- the method 1200 may include controlling, by the control unit 116 , the isolation valve 120 to close the flow path to prevent the refrigerant stored in the charge compensator 110 from flowing, during a defrost mode operation of the heat pump system 100 , 400 , 500 , 800 , from the charge compensator 110 to the system refrigerant circulation piping through the liquid line piping.
- the flow path may be through the isolation valve 120 , 502 or may be controlled by the isolation valve 120 , 502 .
- the method 1200 may include other steps including opening or keeping open the flow path for the refrigerant stored in the charge compensator 110 to flow, during a cooling mode operation of the heat pump system, from the charge compensator 110 to the system refrigerant circulation piping through the liquid line piping.
- the method 1200 may also include providing, by the relief valve 402 , a bypass flow path for at least a portion of the refrigerant stored in the charge compensator 110 to flow from the charge compensator 110 to the system refrigerant circulation piping of the heat pump system if a pressure in the charge compensator 110 exceeds a threshold.
- the method 1200 may include more or fewer steps than described above without departing from the scope of this disclosure. In some example embodiments, some of the steps of the method 1200 may be performed in a different order than described above.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Air Conditioning Control Device (AREA)
Abstract
Description
- The present application is a continuation U.S. patent application Ser. No. 16/428,453 31 May 2019, the entire contents of which is incorporated herein by reference.
- The present disclosure relates generally to heat pump systems, and more particularly to improved defrosting operations of heat pump systems.
- Heat pump systems typically operate in a heating mode and a cooling mode. When operating in a cooling mode to cool a particular space, the outdoor coil of a heat pump system operates as a condenser that dissipates heat outdoors. When the operating in a heating mode to heat a particular space, the outdoor coil of a heat pump system operates as an evaporator. In some cases, frost may form on the outdoor coil during heating mode operations, which may result in inefficient operations of the heat pump system. To remove the frost from the outdoor coil, the heat pump system typically interrupts a heating mode operation and temporarily operates in a cooling mode that is generally referred to as a defrost mode to distinguish it from typical cooling mode operations performed for the purpose of cooling a particular space.
- During typical cooling mode operations, refrigerant that is removed from circulation and stored in a charge compensator during the heating mode operation is returned back to circulation. As in typical cooling operations, during defrost mode operations, refrigerant that is removed from circulation and stored in the charge compensator during the heating mode operation is also returned back to circulation. The refrigerant that is returned to circulation from the charge compensator during a defrost operation may result in the defrost mode operation lasting longer than desired. For example, a longer defrost operation may be undesirable because of the longer interruption of a heating mode operation, which is a normal mode of operation of the heat pump system but for the need to defrost the outdoor coil. Thus a solution that results in shorter defrost operations of heat pump systems may be desirable.
- The present disclosure relates generally to heat pump systems, and more particularly to improved defrosting operations of heat pump systems. In some example embodiments, a heat pump system including a charge compensator having a liquid line port for an inflow of a refrigerant into the charge compensator and for an outflow of the refrigerant from the charge compensator. The heat pump system further includes an isolation valve configured to control flows of the refrigerant to and from the charge compensator through a liquid line piping of the heat pump system based on whether the heat pump system is operating in a cooling mode, a defrost mode, or a heating mode, where the liquid line port is fluidly coupled to the liquid line piping of the heat pump system.
- In another example embodiment, a method of operating a heat pump system that includes an isolation valve includes controlling, by a control unit, the isolation valve to provide an inflow path for a refrigerant to flow to a charge compensator during a heating mode operation of the heat pump system. The charge compensator includes a liquid line port for an inflow of the refrigerant into the charge compensator and for an outflow of the refrigerant from the charge compensator. The method further includes controlling, by the control unit, the isolation valve to prevent the refrigerant from flowing from the charge compensator to a system refrigerant circulation piping of the heat pump system through a liquid line piping of the heat pump system during a defrost mode operation of the heat pump system.
- In another example embodiment, a method of operating a heat pump system that includes an isolation valve includes opening, by the isolation valve, a flow path for a refrigerant to flow, during a heating mode operation of the heat pump system, from a system refrigerant circulation piping to a charge compensator through a liquid line piping. The charge compensator includes a liquid line port that is coupled to the liquid line piping. The method further includes storing, by the charge compensator, the refrigerant and closing, by the isolation valve, the flow path to prevent the refrigerant stored in the charge compensator from flowing, during a defrost mode operation of the heat pump system, from the charge compensator to the system refrigerant circulation piping through the liquid line piping.
- These and other aspects, objects, features, and embodiments will be apparent from the following description and the appended claims.
- Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
-
FIG. 1 illustrates a heat pump system including an isolation valve according to an example embodiment; -
FIG. 2 illustrates the heat pump system ofFIG. 1 configured for a defrost mode operation according to an example embodiment; -
FIG. 3 illustrates the heat pump system ofFIG. 1 configured for a cooling mode operation according to an example embodiment; -
FIG. 4 illustrates a heat pump system including an isolation valve according to another example embodiment; -
FIG. 5 illustrates a heat pump system including an isolation valve according to another example embodiment; -
FIG. 6 illustrates the heat pump system ofFIG. 5 configured for a defrost mode operation according to an example embodiment; -
FIG. 7 illustrates the heat pump system ofFIG. 5 configured for a cooling mode operation according to an example embodiment; -
FIG. 8 illustrates a heat pump system including an isolation valve according to another example embodiment; -
FIG. 9 illustrates the heat pump system ofFIG. 8 configured for a defrost mode operation according to an example embodiment; -
FIG. 10 illustrates the heat pump system ofFIG. 8 configured for a cooling mode operation according to an example embodiment; -
FIG. 11 illustrates a method of operating a heat pump system that includes an isolation valve according to an example embodiment; and -
FIG. 12 illustrates a method of operating a heat pump system that includes an isolation valve according to another example embodiment. - The drawings illustrate only example embodiments and are therefore not to be considered limiting in scope. The elements and features shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the example embodiments. Additionally, certain dimensions or placements may be exaggerated to help visually convey such principles. In the drawings, the same reference numerals that are used in different drawings may designate like or corresponding but not necessarily identical elements.
- In the following paragraphs, example embodiments will be described in further detail with reference to the figures. In the description, well-known components, methods, and/or processing techniques are omitted or briefly described. Furthermore, reference to various feature(s) of the embodiments is not to suggest that all embodiments must include the referenced feature(s).
- In some example embodiments, an isolation valve is located along a refrigerant line connecting the charge compensator to the liquid line of a heat pump system to control the flow of refrigerant into and out of the charge compensator of the heat pump system based on the mode of operation of the heat pump system. The charge compensator typically stores extra refrigerant in during heating mode operations and returns the stored refrigerant back into circulation for the cooling mode operations as readily understood by those of ordinary skill in the art with the benefit of this disclosure. During cooling mode operations, the isolation valve is open, allowing refrigerant to flow out of the charge compensator into circulation. During defrost mode operations that interrupt heat mode operations, the isolation valve is closed, thereby isolating the refrigerant in the charge compensator from combining with the refrigerant in circulation in the rest of the system. Isolating the charge compensator during defrost mode operations prevents the refrigerant in the charge compensator entering circulation through the heat pump system, which allows for higher discharge temperature of gas refrigerant leaving the compressor of the heat pump system resulting in faster defrosting of the outdoor coil.
- In some example embodiments, a relief valve (e.g., an in-line relief valve) may be placed in parallel with the isolation valve to prevent excessive pressure from building in the charge compensator when the isolation valve is preventing refrigerant flow from the charge compensator into system circulation. The relief valve may be a spring loaded spring valve or another pressure-actuated valve that opens to relieve pressure when the pressure in the charge compensator reaches or exceeds a safety threshold and stays closed prior to the pressure reaching or exceeding the safety threshold. In some example embodiments, the isolation valve may be controlled to release some of the refrigerant stored in the charge compensator into the system circulation during defrost mode operations instead of fully isolating the charge compensator during entire defrost mode operations.
- Turning now to the figures, particular example embodiments are described.
FIG. 1 illustrates aheat pump system 100 including anisolation valve 120 according to an example embodiment. In some example embodiments, theheat pump system 100 includes anindoor coil 102, anoutdoor coil 104, and theisolation valve 120. Theheat pump system 100 may include acompressor 106, areversing valve 108, and acharge compensator 110. Theheat pump system 100 may also includeexpansion devices expansion devices - In some example embodiments, a
control unit 116 may control the operation modes of theheat pump system 100. To illustrate, thecontrol unit 116 may control thereversing valve 108 to control the operation modes of theheat pump system 100 by controlling the direction of system refrigerant flow through the system refrigerant circulation piping of theheat pump system 100. To illustrate, to operate in a heating mode, thecontrol unit 116 may control the reversingvalve 108 such that the system refrigerant circulates through the system refrigerant circulation piping in the directions shown by the solid arrows, such as thearrow 132. For example, the system refrigerant circulation piping may includerefrigerant pipes valve 108 and theindoor coil 102, thecompressor 106, and thecharge compensator 110 as well as between theoutdoor coil 104 and thecharge compensator 110. - When configured to operate in a heating mode as shown in
FIG. 1 , thecontrol unit 116 may configure the reversingvalve 108 such that system (i.e., circulating) refrigerant flows from theoutdoor coil 104 to the suction port of thecompressor 106 through the reversingvalve 108 and through the charge compensator 110 (i.e., through the flow path 136) and such that the system/circulating refrigerant flows from the discharge port of thecompressor 106 to theindoor coil 102 through the reversingvalve 108. The circulation of the system refrigerant through the system refrigerant circulation piping is completed by the flow of the system refrigerant from theindoor coil 102 to theoutdoor coil 104 through theexpansion devices heat pump system 100 is configured to operate in a heating mode as shown inFIG. 1 , theoutdoor coil 104 operates as an evaporator, and theindoor coil 102 operates as a condenser. During heat mode operations, theexpansion device 112 throttles the refrigerant flow on the lower pressure side from a higher pressure to a lower pressure while theexpansion device 114 acts as a flow passage. During cooling mode operations, theexpansion device 114 throttles the refrigerant flow while theexpansion device 112 acts as a flow passage. - In some example embodiments, the
isolation valve 120 is located to control flows of refrigerant through a liquid line piping of theheat pump system 100. For example, theisolation valve 120 may be a solenoid valve or another type of valve as can be readily understood by those of ordinary skill in the art with the benefit of this disclosure. Theisolation valve 120 may provide a single flow path that, when open, allows the flow of refrigerant in both directions depending on the mode of operation of theheat pump system 100. Alternatively, theisolation valve 120 may provide two single direction flow paths or bidirectional that are open or closed under the control of thecontrol unit 116. - In some example embodiments, the liquid line piping may include
pipe sections charge compensator 110 and therefrigerant pipe 130. Theisolation valve 120 may be in-line with or otherwise coupled to the liquid line piping to control refrigerant flows through the liquid line piping from and to thecharge compensator 110 and therefrigerant pipe 130. For example, thepipe section 128 of the liquid line piping may be fluidly coupled to aliquid line port 118 of thecharge compensator 110, and thepipe section 126 of the liquid line piping may be fluidly coupled to therefrigerant pipe 130 of the system refrigerant circulation piping. - In some example embodiments, the
control unit 116 may control theisolation valve 120 to control flows of refrigerant from and to thecharge compensator 110 and therefrigerant pipe 130 through the liquid line piping includingpipe sections control unit 116 may send a control signal via anelectrical connection 138 to the isolation valve 120 (e.g., a solenoid valve) to control the state of theisolation valve 120. When theheat pump system 100 starts operating in a heating mode from being idle or from a cooling mode, thecontrol unit 116 may control theisolation valve 120 to open or keep open a flow path for refrigerant to flow from therefrigerant pipe 130 to thecharge compensator 110 through the liquid line piping includingpipe sections charge compensator 110 through the liquid line piping and theisolation valve 120 as illustrated by the dottedarrow 134. Thecontrol unit 116 may control theisolation valve 120 to allow the flow of refrigerant to thecharge compensator 110 through the liquid line piping until thecharge compensator 110 is full or at a certain fill level. For example, thecontrol unit 116 may control theisolation valve 120 such that theisolation valve 120 is open to allow the refrigerant to flow to thecharge compensator 110 through theisolation valve 120. - In some example embodiments, during heating mode operations, after some refrigerant is taken out of system circulation into the
charge compensator 110 through the liquid line piping, thecontrol unit 116 may control the isolation valve 120 (e.g., close the isolation valve 120) to prevent more refrigerant from flowing to thecharge compensator 110 through the liquid line piping. For example, thecontrol unit 116 may control theisolation valve 120 to close the flow path to thecharge compensator 110 through the liquid line piping after a period of time following the start of a heating mode operation. The period of time that thecontrol unit 116 waits before controlling theisolation valve 120 to stop the flow to thecharge compensator 110 may depend on the system capacity, the size of thecharge compensator 110, etc. as can be readily understood by those of ordinary skill in the art with the benefit of this disclosure. Once theisolation valve 120 is closed or the refrigerant flow to thecharge compensator 110 is stopped during the heating mode operation, theisolation valve 120 may remain closed for the duration of the particular heating operation. - In some alternative embodiments, after some refrigerant is taken out of system circulation into the
charge compensator 110 through the liquid line piping during a heating mode operation, thecontrol unit 116 may control theisolation valve 120 to keep the flow path through the liquid line piping open until the operation mode of theheat pump system 100 is changed or needs to be changed to a defrost mode. To illustrate, thecontrol unit 116 may determine that a defrost mode operation needs to be performed to remove frost from theoutdoor coil 104, for example, based on an input from a frost thermostat at theoutdoor coil 104. If thecontrol unit 116 determines that a defrost mode operation needs to be performed, thecontrol unit 116 may control the reversingvalve 108 to change the operation mode of theheat pump system 100 to a defrost mode and control theisolation valve 120 to prevent the refrigerant stored in thecharge compensator 110 during a heating mode operation from flowing to therefrigerant pipe 130 through the liquid line piping. For example, thecontrol unit 116 may send a control signal to theisolation valve 120 to close theisolation valve 120 or otherwise close a flow path from thecharge compensator 110 to therefrigerant pipe 130 through the liquid line piping. - In some example embodiments, if the
heat pump system 100 returns to a heating mode operation following a defrost mode operation (i.e., without going into a cooling mode operation), thecontrol unit 116 may control theisolation valve 120 to keep the refrigerant flow path between therefrigerant pipe 130 and thecharge compensator 110 through the liquid line piping closed. Alternatively, thecontrol unit 116 may control theisolation valve 120 to open the refrigerant flow path from therefrigerant pipe 130 to thecharge compensator 110 through the liquid line piping if theheat pump system 100 returns to a heating mode operation following the defrost mode operation. - In some example embodiments, the
control unit 116 may control theisolation valve 120 to allow the refrigerant that is stored in thecharge compensator 110 during a heating mode operation to return to therefrigerant pipe 130 through the liquid line piping by flowing in the opposite direction to the dottedarrow 134. For example, thecontrol unit 116 may control the reversingvalve 108 to change the operation mode of theheat pump system 100 to a cooling mode and control theisolation valve 120 to allow the refrigerant stored in thecharge compensator 110 to flow to therefrigerant pipe 130 through the liquid line piping. Thecontrol unit 116 may control theisolation valve 120 to keep the refrigerant flow path through the liquid line piping between thecharge compensator 110 and therefrigerant pipe 130 open through the entire cooling mode operation. - In some example embodiments, the
control unit 116 may control the reversingvalve 108 to change the operation mode of theheat pump system 100 at substantially the same time (e.g., 10 seconds, 5 seconds, 100 milliseconds, etc. before or after) that thecontrol unit 116 controls theisolation valve 120 to open or close the flow path of refrigerant through the liquid line piping. For example, thecontrol unit 116 may include a microprocessor or a microcontroller, one or more memory devices, and other components and may send respective control signals to the reversingvalve 108 and theisolation valve 120. To illustrate, a microcontroller of thecontrol unit 116 may execute a software code stored in a memory device of thecontrol unit 116 to perform some of the operation described herein with respect to thecontrol unit 116. - In some alternative embodiments, the
heat pump system 100 may include other components than shown inFIG. 1 without departing from the scope of this disclosure. For example, theheat pump system 100 may include a filter-drier between theexpansion devices pipe section 126 to therefrigerant pipe 130 and theexpansion device 112. In some alternative embodiments, some of the components of theheat pump system 100 may be integrated into a single component without departing from the scope of this disclosure. For example, theisolation valve 120 may be integrated into thecharge compensator 110. -
FIG. 2 illustrates theheat pump system 100 ofFIG. 1 configured for a defrost mode operation according to an example embodiment. As shown inFIG. 2 , the reversingvalve 108 is controlled bycontrol unit 116 to operate in a defrost mode such that the system refrigerant flows through the system refrigerant circulation piping in directions shown by the solid arrows such as thesolid arrow 204. When theheat pump system 100 is configured to operate in a defrost mode as shown inFIG. 2 , the system refrigerant flows from theindoor coil 102 to the suction port of thecompressor 106 through the reversingvalve 108 and from the discharge port of thecompressor 106 to theoutdoor coil 104 through the reversingvalve 108 and thecharge compensator 110. The configuration of the reversingvalve 108 as shown inFIG. 2 provides a flow path for the system refrigerant to flow from theindoor coil 102 to theoutdoor coil 104 through the reversingvalve 108 and through the charge compensator 110 (i.e., through the flow path 136). When theheat pump system 100 is configured to operate in a defrost mode as shown inFIG. 2 , theoutdoor coil 104 operates as a condenser, which allows theoutdoor coil 104 to dissipate heat to defrost theoutdoor coil 104. - In some example embodiments, the
heat pump system 100 may be configured to operate in the defrost mode in response to a frost build-up on theoutdoor coil 104 during a heating mode operation of theheat pump system 100. As described above, thecontrol unit 116 may determine that theheat pump system 100 needs to operate in a defrost mode operation to remove frost from theoutdoor coil 104, for example, based on an input from a temperature sensor at theoutdoor coil 104. Alternatively, thecontrol unit 116 may determine the need to operate in a defrost mode using other means as can be readily understood by those of ordinary skill in the art with the benefit of this disclosure. In some alternative embodiments, thecontrol unit 116 may be configured to periodically interrupt heating mode operations of theheat pump system 100 and to operate theheat pump system 100 in a defrost mode to remove frost that may accumulate on theoutdoor coil 104. - As illustrated in
FIG. 2 , during defrost mode operations, theisolation valve 120 is closed or otherwise prevents the flow of refrigerant from thecharge compensator 110 to the system refrigerant circulation piping that includes therefrigerant pipe 130. To illustrate, if the flow path of refrigerant from thecharge compensator 110 to the system refrigerant circulation piping was closed during the immediately prior heating mode operation, thecontrol unit 116 may maintain the flow path closed using theisolation valve 120 when theheat pump system 100 enters the defrost mode. If the flow path of refrigerant from thecharge compensator 110 to the system refrigerant circulation piping was open during the immediately prior heating mode operation, thecontrol unit 116 may close the flow path using theisolation valve 120 when theheat pump system 100 enters the defrost mode. By preventing the return of refrigerant from thecharge compensator 110 into system circulation during defrost mode operations, a higher discharge temperature of the refrigerant leaving thecompressor 106 may be achieved, resulting in faster defrosting of theoutdoor coil 104. - In some example embodiments, after the defrost operation is performed, the
control unit 116 may configure the reversingvalve 108 to operate theheat pump system 100 back in a heating mode. For example, thecontrol unit 116 may operate theheat pump system 100 in the defrost mode until the temperature of the outdoor coil reaches a particular temperature (e.g., above 55° F.) or may operate in the defrost mode for a time period (dependent on the particular system) that would allow adequate defrosting. Immediately before, at the same time, or after configuring the reversingvalve 108 to operate in a heating mode from the defrost mode operation, thecontrol unit 116 may control theisolation valve 120 such that the refrigerant flow path through the liquid line piping is open. Alternatively, thecontrol unit 116 may control theisolation valve 120 to keep the refrigerant flow path through the liquid line piping closed during the heating mode operation that is subsequent to the defrost mode operation. - In some alternative embodiments, during defrost mode operations of the
heat pump system 100, thecontrol unit 116 may control theisolation valve 120 such that, instead of preventing the flow of the refrigerant stored in thecharge compensator 110 to the system refrigerant circulation piping, some of the refrigerant flows to the system refrigerant circulation piping. For example, thecontrol unit 116 may control theisolation valve 120 for a duration of time at the start of the defrost mode of operation. The duration of time may vary depending on the system capacity, the capacity of thecharge compensator 110, etc. -
FIG. 3 illustrates theheat pump system 100 ofFIG. 1 configured for a cooling mode operation according to an example embodiment. The cooling mode configuration of the reversingvalve 108 as shown inFIG. 3 is the same as the defrost mode configuration of the reversingvalve 108 shown inFIG. 2 . To illustrate, when theheat pump system 100 is configured to operate in a cooling mode as shown inFIG. 3 , the system refrigerant flows from theindoor coil 102 to the suction port of thecompressor 106 through the reversingvalve 108 and from the discharge port of thecompressor 106 to theoutdoor coil 104 through the reversingvalve 108 and thecharge compensator 110. As shown inFIG. 3 , the reversingvalve 108 provides a flow path for the system refrigerant to flow from theindoor coil 102 to theoutdoor coil 104 through the reversingvalve 108 and through the charge compensator 110 (i.e., through the flow path 136). - As illustrated in
FIG. 3 , during cooling mode operations, theisolation valve 120 is open or otherwise allows the flow of refrigerant from thecharge compensator 110 to the system refrigerant circulation piping as shown by thearrow 302. If theisolation valve 120 was configured to allow refrigerant flow from thecharge compensator 110 through the liquid line piping during an immediately prior heating mode operation, thecontrol unit 116 may maintain the configuration of theisolation valve 120 when theheat pump system 100 enters the cooling mode. If theisolation valve 120 was configured to prevent refrigerant flow from thecharge compensator 110 through the liquid line piping during the immediately prior heating mode operation, thecontrol unit 116 may control theisolation valve 120 to allow refrigerant flow from thecharge compensator 110 to therefrigerant pipe 130 through the liquid line piping when theheat pump system 100 enters the cooling mode. - Referring to
FIGS. 1-3 , by preventing the return of refrigerant from thecharge compensator 110 into system circulation during defrost mode operations, a higher discharge temperature of the refrigerant leaving thecompressor 106 may be achieved, resulting in faster defrosting of theoutdoor coil 104. By allowing refrigerant to flow to thecharge compensator 110 for storage during heating mode operations, by allowing the stored refrigerant to enter circulation during cooling mode operations, and by preventing the return of the refrigerant from thecharge compensator 110 into circulation during defrost mode operations, theisolation valve 120 allows for more efficient defrosting operations without disrupting the regular cooling and heating mode operations of theheat pump system 100. - In some alternative embodiments, the
isolation valve 120 may be fluidly coupled to the system refrigerant circulation piping at a different location than therefrigerant pipe 130 without departing from the scope of this disclosure. -
FIG. 4 illustrates aheat pump system 400 including theisolation valve 120 according to another example embodiment. In some example embodiments, theheat pump system 400 includes the same components and operates in substantially the same manner as theheat pump system 100. To illustrate, theheat pump system 400 includes theindoor coil 102, theoutdoor coil 104, thecompressor 106, the reversingvalve 108, thecharge compensator 110, theexpansion devices isolation valve 120. In contrast to theheat pump system 100, theheat pump system 400 includes arelief valve 402. - In some example embodiments, the
heat pump system 400 may operate in a heating mode, a defrost mode, and a cooling mode in the same manner as described with respect to theheat pump system 100. To configure theheat pump system 400 to operate in a defrost mode as shown inFIG. 4 , thecontrol unit 116 may configure the reversingvalve 108 such that system (i.e., circulating) refrigerant flows from theindoor coil 102 to the suction port of thecompressor 106 through the reversingvalve 108 and from the discharge port of thecompressor 106 to theoutdoor coil 104 through the reversingvalve 108 and thecharge compensator 110. The configuration of the reversingvalve 108 as shown inFIG. 4 provides a flow path for the system refrigerant to flow from theindoor coil 102 to theoutdoor coil 104 through the reversingvalve 108 and through the charge compensator 110 (i.e., through the flow path 136). When theheat pump system 400 is configured to operate in a defrost mode as shown inFIG. 4 , theoutdoor coil 104 operates as a condenser, which allows theoutdoor coil 104 to dissipate heat to remove frost from theoutdoor coil 104 that might have accumulated, for example, during a heating mode operation. - In some example embodiments, the
isolation valve 120 operates in the same manner as described above with respect to theheat pump system 100. For example, during a defrost mode operation of theheat pump system 400, theisolation valve 120 is closed or otherwise prevents refrigerant stored in thecharge compensator 110 from flowing from thecharge compensator 110 to the system refrigerant circulation piping through the liquid line piping that includes thepipes valve 108 has the same configuration as in defrost mode operations, theisolation valve 120 is open or otherwise allows refrigerant stored in thecharge compensator 110 to flow from thecharge compensator 110 to the system refrigerant circulation piping through the liquid line piping. - During heating mode operations, the
isolation valve 120 may be open or otherwise allow some of the system refrigerant to flow to thecharge compensator 110 through the liquid line piping. For example, theisolation valve 120 may be open during all heating mode operations. Alternatively, theisolation valve 120 may be open during a heating mode operation and may then be closed when theheat pump system 400 switches to a defrost mode operation. Upon theheat pump system 400 returning to a subsequent heating mode operation from a defrost mode operation, theisolation valve 120 may remain closed for the duration of the subsequent heating mode operation. Alternatively, when theheat pump system 400 first enters a heating mode operation, theisolation valve 120 may be opened or otherwise allow some of the system refrigerant to flow to thecharge compensator 110 through the liquid line piping. Theisolation valve 120 may be closed by thecontrol unit 116 when thecharge compensator 110 fills up or is filled by refrigerant to a particular fill level. - In some example embodiments, the
relief valve 402 may be placed in parallel with theisolation valve 120 to provide a bypass flow path to protect against excessive pressure build up in thecharge compensator 110 when theisolation valve 120 is closed or otherwise prevents the flow of refrigerant from thecharge compensator 110 to therefrigerant pipe 130. Therelief valve 402 may be a spring loaded spring valve or another type of pressure-actuated valve that opens to relieve pressure in thecharge compensator 110 when the pressure in thecharge compensator 110 or across therelief valve 402 reaches or exceeds a threshold. Therelief valve 402 may close when the pressure in thecharge compensator 110 or across therelief valve 402 is below threshold. - For example, the
relief valve 402 may be an in-line relief valve that open to provide a refrigerant flow path through therelief valve 402 in a direction shown by thearrow 404 when the pressure in thecharge compensator 110 reaches or exceeds a threshold or when the pressure across therelief valve 402 reaches or exceeds a threshold. When opened, the refrigerant flow path through therelief valve 402 allows some of the refrigerant stored in thecharge compensator 110 to flow to therefrigerant pipe 130, resulting in a decreased pressure inside thecharge compensator 110. The flow path through therelief valve 402 closes when the pressure in thecharge compensator 110 or the pressure across therelief valve 402 decreases, for example, to below a threshold level. The pressure threshold levels for opening the flow path through therelief valve 402 in the direction shown by thearrow 404 may depend on the system capacity, the capacity of thecharge compensator 110, etc. as can be readily understood by those of ordinary skill in the art with the benefit of this disclosure. - By allowing refrigerant to flow to the
charge compensator 110 for storage during heating mode operations, by allowing the stored refrigerant to enter circulation during cooling mode operations, and by preventing the return of the refrigerant from thecharge compensator 110 into circulation during defrost mode operations, theisolation valve 120 allows for more efficient defrosting operations without disrupting the regular cooling and heating mode operations of theheat pump system 400. By allowing pressure reduction in thecharge compensator 110 as needed, therelief valve 402 may provide improved system performance by reducing the risk of system malfunction. - In some alternative embodiments, the
relief valve 402 may be coupled in a different piping configuration than shown without departing from the scope of this disclosure. For example, theisolation valve 120 and therelief valve 402 may be fluidly coupled to therefrigerant pipe 130 using separate pipes instead of thepipe section 126 without departing from the scope of this disclosure. In some alternative embodiments, theheat pump system 400 may include other components than shown inFIG. 4 without departing from the scope of this disclosure. For example, theheat pump system 400 may include a filter-drier between theexpansion devices heat pump system 400 may be integrated into a single component without departing from the scope of this disclosure. For example, theisolation valve 120 may be integrated into thecharge compensator 110. -
FIGS. 5-7 illustrate aheat pump system 500 including anisolation valve 502 according to another example embodiment. As shown inFIG. 5 , theheat pump system 500 is configured for heating mode operations. As shown inFIG. 6 , theheat pump system 500 is configured for defrost mode operations. As shown inFIG. 7 , theheat pump system 500 is configured for cooling mode operations. Theheat pump system 500 includes components described above with respect to theheat pump system 100. To illustrate, theheat pump system 500 includes theindoor coil 102, theoutdoor coil 104, thecompressor 106, the reversingvalve 108, thecharge compensator 110, theexpansion devices - In some example embodiments, the
control unit 116 controls the reversingvalve 108 to configure theheat pump system 500 in a heating mode, a cooling mode, and a defrost mode in the same manner as described above with respect to theheat pump system 100. In contrast to theheat pump system 100, theheat pump system 500 includes theisolation valve 502 that is temperature actuated instead of being controlled by thecontrol unit 116. To illustrate, theheat pump system 500 may include a temperature sensor 504 (e.g., a temperature sensing bulb) that is coupled to theisolation valve 502. For example, thetemperature sensor 504 may be positioned to sense the temperature of the system refrigerant flowing between theindoor coil 102 and the reversingvalve 108 as shown inFIG. 1 . Alternatively, thetemperature sensor 504 be positioned at a different location, such as thelocation - In some example embodiments, the
isolation valve 502 may operate as a typical temperature actuated valve that responds to an input corresponding to a temperature that is below or above a threshold temperature. To illustrate, theisolation valve 502 may be opened or closed in response to an input provided from thetemperature sensor 504. For example, thetemperature sensor 504 may be configured to provide a frost indicator input to theisolation valve 502 when the system refrigerant temperature, as sensed by thetemperature sensor 504, reaches or decreases to below a frost threshold temperature (e.g., 35° F.) that is indicative of a frost accumulation on theoutdoor coil 104. To illustrate, thetemperature sensor 504 may be configured to provide the frost indicator input to theisolation valve 502 when the temperature of the system refrigerant, as sensed by thetemperature sensor 504, corresponds to a frost condition that would trigger thecontrol unit 116 to configure the reversingvalve 108 for a defrost mode operation of theheat pump system 500. In response to the frost indicator input from thetemperature sensor 504, theisolation valve 502 may close or otherwise prevent the flow of refrigerant from thecharge compensator 110 to therefrigerant pipe 130 through the liquid line piping. - In some example embodiments, when the
temperature sensor 504 no longer provides the frost indicator input to theisolation valve 502 or provides a different input corresponding to a temperature of the system refrigerant that is higher than the frost threshold temperature or another higher temperature, theisolation valve 502 may open or otherwise allow the flow of refrigerant from thecharge compensator 110 to therefrigerant pipe 130 through the liquid line piping. For example, thetemperature sensor 504 may be configured to stop providing the frost indicator input or to provide another input to theisolation valve 502 when the temperature of the system refrigerant, as sensed by thetemperature sensor 504, corresponds to a condition indicative of thecontrol unit 116 operating theheat pump system 500 in a mode (heating or cooling mode) other than the defrost mode. - In some alternative embodiments, instead of or in addition to the
temperature sensor 504, thesystem 500 may include an air temperature sensor 510 (e.g., a temperature sensing bulb) that is located close to theoutdoor coil 104. Theair temperature sensor 510 may be located to sense air temperature at theoutdoor coil 104 without being directedly attached to theoutdoor coil 104. For example, theair temperature sensor 510 may be located upstream of theoutdoor coil 104 such that the air temperature sensed by thetemperature sensor 504 is not meaningfully affected by air flow over theoutdoor coil 104. Alternatively, theair temperature sensor 510 may be located at a different relative position with respect to the outdoor coil 104 (e.g., downstream of the outdoor coil 104), where the air temperature sensed by theair temperature sensor 504 may be meaningfully affected by air flow over theoutdoor coil 104. In some example embodiments, thetemperature sensor 504 may even be located inside an outdoor unit that includes theoutdoor coil 104 without being directly attached to theoutdoor coil 104 itself. In some alternative embodiments, thetemperature sensor 510 may be at a different location than shown inFIG. 5 or described above, without departing from the scope of this disclosure. - In some example embodiments, the
isolation valve 502 may operate based on an input provided from thetemperature sensor 510 in a similar manner as described with respect to thetemperature sensor 504. For example, theisolation valve 502 may operate as a typical temperature actuated valve that responds to the input from thetemperature sensor 510 corresponding to a temperature that is below or above a threshold air temperature. To illustrate, theisolation valve 502 may be opened or closed in response to the input provided from thetemperature sensor 510. For example, thetemperature sensor 510 may be configured to provide a valve control input to theisolation valve 502 that indicates whether the air temperature, as sensed by theair temperature sensor 510, is at, below, and/or above the threshold air temperature. - To illustrate, when the air temperature sensed by the
air temperature sensor 510 is above the threshold air temperature, the valve control input from theair temperature sensor 510 may indicate that the isolation valve should be open. When the air temperature sensed by theair temperature sensor 510 is at or below the threshold air temperature, the valve control input from theair temperature sensor 510 may indicate that the isolation valve should be closed. Theisolation valve 502 may open (or otherwise allow refrigerant flow between thecharge compensator 110 and therefrigerant pipe 130 through the liquid line piping) or close (or otherwise prevent the flow of refrigerant from thecharge compensator 110 to therefrigerant pipe 130 through the liquid line piping) depending on the valve control input from thetemperature sensor 510. As a non-limiting example, the threshold air temperature may be within a temperature range of 35° F. to 50° F. (e.g., a temperature in 45° F.) when theair temperature sensor 510 is on the upstream side of theoutdoor coil 104. The temperature range by be slightly different (e.g., lower values at both end limits) when theair temperature sensor 510 is on the downstream side of theoutdoor coil 104 where the air temperature sensed by theair temperature sensor 510 may be affected by air flow passing over theoutdoor coil 104. In general, the upper limit of the temperature range may be set such that, when thesystem 500 starts operating in the heat mode, some of the refrigerant circulating in thesystem 500 can enter thecharge compensator 110 through theisolation valve 502 before theisolation valve 502 is closed for the duration of the heating mode operation. In some alternative embodiments, the threshold air temperature for opening theisolation valve 502 may be different from the threshold air temperature for closing theisolation valve 502. - By preventing the refrigerant stored in the
charge compensator 110 from entering the system refrigerant circulation piping through the liquid line piping during defrost mode operations and by allowing refrigerant flow to and from thecharge compensator 110 through the liquid line piping during other modes of operations, theisolation valve 502 allows for more efficient defrosting operations without disrupting regular cooling and heating mode operations of theheat pump system 500. - In some alternative embodiments, the
air temperature sensor 510 may be used in conjunction with thetemperature sensor 504 to control the opening and closing of theisolation valve 502. For example, particular temperature/condition related indications from bothsensors isolation valve 502. Alternatively, a temperature/condition related indication from one of the twosensors isolation valve 502. In some alternative embodiments, theheat pump system 500 may include therelief valve 402 shown inFIG. 4 without departing from the scope of this disclosure. For example, therelief valve 402 may be integrated in theheat pump system 500 in the same or similar configuration as in theheat pump system 400. In some alternative embodiments, theheat pump system 500 may include other components than shown inFIG. 5 without departing from the scope of this disclosure. For example, theheat pump system 500 may include a filter-drier between theexpansion devices heat pump system 500 may be integrated into a single component without departing from the scope of this disclosure. For example, theisolation valve 120 may be integrated into thecharge compensator 110. -
FIGS. 8-10 illustrate aheat pump system 800 including theisolation valve 120 according to another example embodiment. As shown inFIG. 8 , theheat pump system 800 is configured for heating mode operations. As shown inFIG. 9 , theheat pump system 800 is configured for defrost mode operations. As shown inFIG. 10 , theheat pump system 800 is configured for cooling mode operations. - In some example embodiments, the
heat pump system 800 includes components described above with respect to theheat pump system 100. To illustrate, theheat pump system 800 includes theindoor coil 102, theoutdoor coil 104, thecompressor 106, the reversingvalve 108, thecharge compensator 110, and theisolation valve 120. theexpansion devices heat pump system 100, theheat pump system 800 includes a bidirectional expansion device 802 (e.g., a thermal expansion device or another type of expansion device) instead of theexpansion devices pipe section 126 of the liquid line piping of theheat pump system 800 is fluidly coupled to the system refrigerant circulation piping at therefrigerant pipe 122. For example, theexpansion device 802 may be electronically or thermally activated. - In some example embodiments, the
heat pump system 800 operates in heating modes, cooling modes, and defrost modes in the same manner as described above with respect to theheat pump system 100. To illustrate, thecontrol unit 116 may control the reversingvalve 108 to control the mode of operation of theheat pump system 800. Thecontrol unit 116 may also control theisolation valve 120 to control whether refrigerant flows to and from thecharge compensator 110 during different operation modes of theheat pump system 800 in the same manner as described with respect to theheat pump system 100. - In some alternative embodiments, the
heat pump system 800 may include therelief valve 402 shown inFIG. 4 . For example, therelief valve 402 may be coupled in parallel with theisolation valve 120 to protect against excessive pressure build up in thecharge compensator 110 when theisolation valve 120 is closed or otherwise prevents the flow of refrigerant from thecharge compensator 110 to therefrigerant pipe 122. - In some alternative embodiments, the
heat pump system 800 may include theisolation valve 502 of theheat pump system 500 instead of theisolation valve 120 shown inFIG. 8 . For example, theheat pump system 800 may include thetemperature sensor 504 that is coupled to theisolation valve 502 in the same manner as shown inFIG. 5 , and theisolation valve 502 may operate based on input(s) from thetemperature sensor 504 as described above instead of operating under the control of thecontrol unit 116. In some alternative embodiments, theheat pump system 800 may include therelief valve 402 as well as theisolation valve 502, where therelief valve 402 is coupled in a similar configuration as described above to protect against excessive pressure build up in thecharge compensator 110. - By allowing refrigerant to flow to the
charge compensator 110 for storage during heating mode operations, by allowing the stored refrigerant to enter circulation during cooling mode operations, and by preventing the return of the refrigerant from thecharge compensator 110 into circulation during defrost mode operations, the isolation valve 120 (alternatively the isolation valve 502) allows for more efficient defrosting operations without disrupting the regular cooling and heating mode operations of theheat pump system 800. When included, therelief valve 402 may provide improved system performance by reducing the risk of system malfunction. - In some alternative embodiments, the
heat pump system 800 may include other components than shown inFIG. 8 without departing from the scope of this disclosure. For example, theheat pump system 800 may include a filter-drier between theexpansion device 802 and theoutdoor coil 104. In some alternative embodiments, some of the components of theheat pump system 800 may be integrated into a single component without departing from the scope of this disclosure. For example, theisolation valve 120 may be integrated into thecharge compensator 110. -
FIG. 11 illustrates amethod 1100 of operating theheat pump system FIGS. 1-11 , in some example embodiments, themethod 1100 includes, atstep 1102, opening, by theisolation valve heat pump system charge compensator 110 through the liquid line piping. For example, the system refrigerant circulation piping may includerefrigerant pipes pipe sections charge compensator 110 includes theliquid line port 118 that is coupled to thepipe sections 128 of the liquid line piping. - In some example embodiments, at
step 1104, themethod 1100 may include storing, by thecharge compensator 110, the refrigerant that flows to thecharge compensator 110 from the system refrigerant circulation piping to thecharge compensator 110 through the liquid line piping. For example, thecharge compensator 110 may store the refrigerant until thecharge compensator 110 is full or until thecharge compensator 110 is filled to a particular level. - In some example embodiments, at
step 1106, themethod 1100 may include closing, by theisolation valve charge compensator 110 from flowing, during a defrost mode operation of theheat pump system charge compensator 110 to the system refrigerant circulation piping through the liquid line piping. For example, the flow path may be through theisolation valve isolation valve - In some example embodiments, the
method 1100 may include other steps including opening or keeping open the flow path for the refrigerant stored in thecharge compensator 110 to flow, during a cooling mode operation of the heat pump system, from thecharge compensator 110 to the system refrigerant circulation piping through the liquid line piping. Themethod 1100 may also include providing, by therelief valve 402, a bypass flow path for at least a portion of the refrigerant stored in thecharge compensator 110 to flow from thecharge compensator 110 to the system refrigerant circulation piping of the heat pump system if a pressure in thecharge compensator 110 exceeds a threshold. - In some alternative embodiments, the
method 1100 may include more or fewer steps than described above without departing from the scope of this disclosure. In some example embodiments, some of the steps of themethod 1100 may be performed in a different order than described above. -
FIG. 12 illustrates amethod 1200 of operating aheat pump system FIGS. 1-10 and 12 , in some example embodiments, themethod 1200 includes, at step 2102, controlling, by thecontrol unit 116, theisolation valve 120 to open a flow path for a refrigerant to flow, during a heating mode operation of theheat pump system charge compensator 110 through the liquid line piping. For example, the system refrigerant circulation piping may includerefrigerant pipes pipe sections charge compensator 110 includes theliquid line port 118 that is coupled to thepipe sections 128 of the liquid line piping. - In some example embodiments, at
step 1204, themethod 1200 may include storing, by thecharge compensator 110, the refrigerant that flows to thecharge compensator 110 from the system refrigerant circulation piping to thecharge compensator 110 through the liquid line piping. For example, thecharge compensator 110 may store the refrigerant until thecharge compensator 110 is full or until thecharge compensator 110 is filled to a particular level. - In some example embodiments, at
step 1206, themethod 1200 may include controlling, by thecontrol unit 116, theisolation valve 120 to close the flow path to prevent the refrigerant stored in thecharge compensator 110 from flowing, during a defrost mode operation of theheat pump system charge compensator 110 to the system refrigerant circulation piping through the liquid line piping. For example, the flow path may be through theisolation valve isolation valve - In some example embodiments, the
method 1200 may include other steps including opening or keeping open the flow path for the refrigerant stored in thecharge compensator 110 to flow, during a cooling mode operation of the heat pump system, from thecharge compensator 110 to the system refrigerant circulation piping through the liquid line piping. Themethod 1200 may also include providing, by therelief valve 402, a bypass flow path for at least a portion of the refrigerant stored in thecharge compensator 110 to flow from thecharge compensator 110 to the system refrigerant circulation piping of the heat pump system if a pressure in thecharge compensator 110 exceeds a threshold. - In some alternative embodiments, the
method 1200 may include more or fewer steps than described above without departing from the scope of this disclosure. In some example embodiments, some of the steps of themethod 1200 may be performed in a different order than described above. - Although particular embodiments have been described herein in detail, the descriptions are by way of example. The features of the embodiments described herein are representative and, in alternative embodiments, certain features, elements, and/or steps may be added or omitted. Additionally, modifications to aspects of the embodiments described herein may be made by those skilled in the art without departing from the spirit and scope of the following claims, the scope of which are to be accorded the broadest interpretation so as to encompass modifications and equivalent structures.
Claims (20)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17/562,280 US20220170673A1 (en) | 2019-05-31 | 2021-12-27 | Heat Pump System Defrosting Operations |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16/428,453 US11209204B2 (en) | 2019-05-31 | 2019-05-31 | Heat pump system defrosting operations |
US17/562,280 US20220170673A1 (en) | 2019-05-31 | 2021-12-27 | Heat Pump System Defrosting Operations |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/428,453 Continuation US11209204B2 (en) | 2019-05-31 | 2019-05-31 | Heat pump system defrosting operations |
Publications (1)
Publication Number | Publication Date |
---|---|
US20220170673A1 true US20220170673A1 (en) | 2022-06-02 |
Family
ID=73550744
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/428,453 Active 2040-01-07 US11209204B2 (en) | 2019-05-31 | 2019-05-31 | Heat pump system defrosting operations |
US17/562,280 Abandoned US20220170673A1 (en) | 2019-05-31 | 2021-12-27 | Heat Pump System Defrosting Operations |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/428,453 Active 2040-01-07 US11209204B2 (en) | 2019-05-31 | 2019-05-31 | Heat pump system defrosting operations |
Country Status (1)
Country | Link |
---|---|
US (2) | US11209204B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20200114031A (en) * | 2019-03-27 | 2020-10-07 | 엘지전자 주식회사 | An air conditioning apparatus |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6379122B1 (en) * | 1999-11-10 | 2002-04-30 | Ingersoll-Rand Company | System and method for automatic thermal protection of a fluid compressing system |
US9163866B2 (en) | 2006-11-30 | 2015-10-20 | Lennox Industries Inc. | System pressure actuated charge compensator |
KR20120047677A (en) * | 2010-11-04 | 2012-05-14 | 엘지전자 주식회사 | Air conditioner |
US9976785B2 (en) | 2014-05-15 | 2018-05-22 | Lennox Industries Inc. | Liquid line charge compensator |
KR101787075B1 (en) * | 2016-12-29 | 2017-11-15 | 이래오토모티브시스템 주식회사 | Heat Pump For a Vehicle |
-
2019
- 2019-05-31 US US16/428,453 patent/US11209204B2/en active Active
-
2021
- 2021-12-27 US US17/562,280 patent/US20220170673A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
US11209204B2 (en) | 2021-12-28 |
US20200378677A1 (en) | 2020-12-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2228612B1 (en) | Refrigeration system | |
US4903495A (en) | Transport refrigeration system with secondary condenser and maximum operating pressure expansion valve | |
US7010927B2 (en) | Refrigerant system with controlled refrigerant charge amount | |
EP2443402B1 (en) | Valve and subcooler for storing refrigerant | |
US10921032B2 (en) | Method of and system for reducing refrigerant pressure in HVAC systems | |
CN105588376B (en) | Refrigerating system, control method thereof and refrigerated transport vehicle | |
US20090282848A1 (en) | Refrigeration system | |
US20220170673A1 (en) | Heat Pump System Defrosting Operations | |
GB2366360A (en) | Constant temperature coolant circulating apparatus | |
US10935290B2 (en) | Pressure spike prevention in heat pump systems | |
WO2017022101A1 (en) | Chilling unit | |
US9163862B2 (en) | Receiver fill valve and control method | |
US20200408446A1 (en) | Systems and methods for preventing overheating in refrigeration systems | |
JPH1030852A (en) | Air conditioner | |
CN111442559B (en) | Enhanced vapor injection system, control method and device thereof, heating equipment and electronic equipment | |
JPH0213908Y2 (en) | ||
EP4202324B1 (en) | A method for controlling a check valve in a refrigeration system | |
ES2931829T3 (en) | Thermal cycling system and control method for a thermal cycling system | |
JPH01179876A (en) | Refrigerating device | |
JPH08313074A (en) | Refrigerating apparatus | |
JP2023512581A (en) | PRESSURE-REGULATED SEMICONDUCTOR WAFER COOLING APPARATUS AND METHOD AND PRESSURE-REGULATOR | |
JPS63233255A (en) | Air conditioner | |
JPH0571863B2 (en) | ||
JP2001194035A (en) | Compression heat pump | |
JPH0642825A (en) | Discharged gas temperature control mechanism for screw compressor |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
AS | Assignment |
Owner name: RHEEM MANUFACTURING COMPANY, GEORGIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:GOPALNARAYANAN, SIVAKUMAR;REEL/FRAME:060696/0229 Effective date: 20190607 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |