US20220268498A1 - Intermediate unit for refrigeration apparatus, and refrigeration apparatus - Google Patents
Intermediate unit for refrigeration apparatus, and refrigeration apparatus Download PDFInfo
- Publication number
- US20220268498A1 US20220268498A1 US17/743,161 US202217743161A US2022268498A1 US 20220268498 A1 US20220268498 A1 US 20220268498A1 US 202217743161 A US202217743161 A US 202217743161A US 2022268498 A1 US2022268498 A1 US 2022268498A1
- Authority
- US
- United States
- Prior art keywords
- pipe
- liquid
- refrigeration
- valve
- refrigerant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000005057 refrigeration Methods 0.000 title claims description 48
- 239000003507 refrigerant Substances 0.000 claims abstract description 205
- 239000007788 liquid Substances 0.000 claims abstract description 88
- 238000004378 air conditioning Methods 0.000 description 32
- 230000006835 compression Effects 0.000 description 22
- 238000007906 compression Methods 0.000 description 22
- 238000001816 cooling Methods 0.000 description 18
- 238000000034 method Methods 0.000 description 13
- 230000008569 process Effects 0.000 description 13
- 238000002347 injection Methods 0.000 description 11
- 239000007924 injection Substances 0.000 description 11
- 238000010438 heat treatment Methods 0.000 description 10
- 230000006837 decompression Effects 0.000 description 8
- 238000013022 venting Methods 0.000 description 8
- 230000008859 change Effects 0.000 description 6
- 230000007246 mechanism Effects 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical group O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000009795 derivation Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000004044 response 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
- F25B40/00—Subcoolers, desuperheaters or superheaters
-
- 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
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
- F25B41/26—Disposition of valves, e.g. of on-off valves or flow control valves of fluid flow reversing 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
- F25B41/40—Fluid line arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- 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
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
- F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2140/00—Control inputs relating to system states
- F24F2140/10—Pressure
- F24F2140/12—Heat-exchange fluid pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
-
- 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
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
- F25B2313/0233—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in parallel arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- 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
- F25B2313/02732—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using two three-way 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
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/029—Control issues
- F25B2313/0293—Control issues related to the indoor fan, e.g. controlling speed
-
- 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
- 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
- F25B2400/06—Several compression cycles arranged in parallel
- F25B2400/061—Several compression cycles arranged in parallel the capacity of the first system being different from the second
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/07—Details of compressors or related parts
- F25B2400/072—Intercoolers therefor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/23—Separators
-
- 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
- F25B2600/2513—Expansion valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
- F25B2600/2519—On-off valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
- F25B2600/2525—Pressure relief valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/19—Pressures
- F25B2700/193—Pressures of the compressor
- F25B2700/1931—Discharge pressures
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
- F25B2700/2104—Temperatures of an indoor room or compartment
Definitions
- the present disclosure relates to an intermediate unit for a refrigeration apparatus and a refrigeration apparatus.
- Patent Document 1 discloses a heat source unit forming part of a refrigeration apparatus. This heat source unit is connected through a connection pipe to a show case or any other suitable object, which is a utilization unit, and circulates a refrigerant between the heat source unit and the utilization unit to perform a refrigeration cycle.
- a first aspect of the present disclosure is directed to an intermediate unit ( 80 ) for a refrigeration apparatus ( 1 ).
- the intermediate unit ( 80 ) is provided between a heat source unit ( 10 ) and a utilization unit ( 60 ).
- the heat source unit ( 10 ) and the utilization unit ( 60 ) are connected together through a liquid connection pipe ( 4 ) and a gas connection pipe ( 5 ) to form the refrigeration apparatus ( 1 ).
- the intermediate unit ( 80 ) includes: a liquid-side pipe ( 81 ) connected to the liquid connection pipe ( 4 ); a first valve ( 18 ) provided for the liquid-side pipe ( 81 ), the first valve ( 18 ) having a variable opening degree; a refrigerant pressure sensor ( 48 ) disposed in a portion of the liquid-side pipe ( 81 ) closer to the utilization unit ( 60 ) than the first valve ( 18 ) is, the refrigerant pressure sensor ( 48 ) being configured to measure a pressure of a refrigerant flowing through the liquid-side pipe ( 81 ); and a controller ( 85 ) configured to adjust the opening degree of the first valve ( 18 ) based on a value measured by the refrigerant pressure sensor ( 48 ).
- FIG. 1 is a piping system diagram illustrating a configuration of a refrigeration apparatus according to an embodiment.
- FIG. 2 is a block diagram illustrating the relationship among controllers, a sensor, and components of a refrigerant circuit.
- FIG. 3 corresponds to FIG. 1 and illustrates a flow of a refrigerant through the refrigerant circuit during a cooling operation.
- FIG. 4 corresponds to FIG. 1 and illustrates a flow of the refrigerant through the refrigerant circuit during a heating operation.
- FIG. 5 corresponds to FIG. 1 and illustrates the state of the refrigerant circuit observed while refrigeration-facility units are in a cooling-suspended state.
- FIG. 6 is a flowchart showing how a hydraulic pressure controller of an embodiment operates to control a first valve.
- FIG. 7 is a graph showing the relationship between the opening degree of a second valve controlled by the hydraulic pressure controller of the embodiment and a value Pk measured by a refrigerant pressure sensor.
- FIG. 8 is a graph showing the relationship between the opening degree of a second valve controlled by a hydraulic pressure controller of a variation of the embodiment and a value Pk measured by a refrigerant pressure sensor.
- FIG. 9 is a block diagram illustrating the relationship between components of an intermediate unit and a hydraulic pressure controller.
- a refrigeration apparatus ( 1 ) of an embodiment can cool an object to be cooled, and can condition indoor air.
- the object to be cooled herein includes air in facilities such as a refrigerator, a freezer, and a show case.
- facilities such as a refrigerator, a freezer, and a show case.
- such facilities are each referred to as a refrigeration-facility.
- the refrigeration apparatus ( 1 ) includes a heat source unit ( 10 ) installed outdoors, a plurality of air-conditioning units ( 50 ) configured to condition indoor air, a plurality of refrigeration-facility units ( 60 ) configured to cool air in a refrigeration-facility, an intermediate unit ( 80 ), and a main controller ( 100 ).
- the number of the heat source unit ( 10 ) is one
- the number of the refrigeration-facility units ( 60 ) is two or more
- the number of the air-conditioning units ( 50 ) is two or more. Note that the number of the refrigeration-facility units ( 60 ) or the air-conditioning units ( 50 ) of the refrigeration apparatus ( 1 ) may be one.
- a refrigerant circulates to perform a refrigeration cycle.
- the refrigerant in the refrigerant circuit ( 6 ) of the present embodiment is carbon dioxide.
- the refrigerant circuit ( 6 ) is configured to perform the refrigeration cycle so that the refrigerant has a pressure equal to or greater than the critical pressure.
- the plurality of air-conditioning units ( 50 ) are connected through a first liquid connection pipe ( 2 ) and a first gas connection pipe ( 3 ) to the heat source unit ( 10 ). In the refrigerant circuit ( 6 ), the plurality of air-conditioning units ( 50 ) are connected together in parallel.
- the plurality of refrigeration-facility units ( 60 ) are connected through a second liquid connection pipe ( 4 ) and a second gas connection pipe ( 5 ) to the heat source unit ( 10 ).
- the plurality of refrigeration-facility units ( 60 ) are connected together in parallel.
- the intermediate unit ( 80 ) is connected to the second liquid connection pipe ( 4 ) and the second gas connection pipe ( 5 ) that connect the heat source unit ( 10 ) and the refrigeration-facility units ( 60 ) together.
- the intermediate unit ( 80 ) is disposed between the heat source unit ( 10 ) and the refrigeration-facility units ( 60 ) in the refrigerant circuit ( 6 ).
- the second liquid connection pipe ( 4 ) includes one first liquid-side trunk pipe ( 4 a ), one second liquid-side trunk pipe ( 4 b ), and liquid-side branch pipes ( 4 c ) equal in number to the refrigeration-facility units ( 60 ).
- the first liquid-side trunk pipe ( 4 a ) is provided for a portion of the intermediate unit ( 80 ) near the heat source unit ( 10 ).
- the second liquid-side trunk pipe ( 4 b ) is provided for a portion of the intermediate unit ( 80 ) near the refrigeration-facility units ( 60 ).
- the first liquid-side trunk pipe ( 4 a ) connects the heat source unit ( 10 ) and the intermediate unit ( 80 ) together.
- One end of the second liquid-side trunk pipe ( 4 b ) is connected to the intermediate unit ( 80 ).
- the other end of the second liquid-side trunk pipe ( 4 b ) is connected to one end of each liquid-side branch pipe ( 4 c ).
- the other end of each liquid-side branch pipe ( 4 c ) is connected to an associated one of the refrigeration-facility units ( 60 ).
- the second gas connection pipe ( 5 ) includes one first gas-side trunk pipe ( 5 a ), one second gas-side trunk pipe ( 5 b ), and gas-side branch pipes ( 5 c ) equal in number to the refrigeration-facility units ( 60 ).
- the first gas-side trunk pipe ( 5 a ) is provided for the portion of the intermediate unit ( 80 ) near the heat source unit ( 10 ).
- the second gas-side trunk pipe ( 5 b ) is provided for the portion of the intermediate unit ( 80 ) near the refrigeration-facility units ( 60 ).
- the first gas-side trunk pipe ( 5 a ) connects the heat source unit ( 10 ) and the intermediate unit ( 80 ) together.
- One end of the second gas-side trunk pipe ( 5 b ) is connected to the intermediate unit ( 80 ).
- the other end of the second gas-side branch pipe ( 5 b ) is connected to one end of each gas-side branch pipe ( 5 c ).
- the other end of each gas-side branch pipe ( 5 c ) is connected to an associated one of the refrigeration-facility units ( 60 ).
- the heat source unit ( 10 ) includes an outdoor fan ( 12 ) and an outdoor circuit ( 11 ).
- the outdoor circuit ( 11 ) includes a compression element (C), a flow path switching mechanism ( 30 ), an outdoor heat exchanger ( 13 ), an outdoor expansion valve ( 14 ), a gas-liquid separator ( 15 ), a subcooling heat exchanger ( 16 ), and an intercooler ( 17 ).
- the heat source unit ( 10 ) further includes an outdoor controller ( 101 ).
- the compression element (C) compresses the refrigerant.
- the compression element (C) includes a first compressor ( 21 ), a second compressor ( 22 ), and a third compressor ( 23 ).
- the first, second, and third compressors ( 21 ), ( 22 ), and ( 23 ) are each a rotary compressor in which a motor drives a compression mechanism.
- the first, second, and third compressors ( 21 ), ( 22 ), and ( 23 ) are each configured as a variable capacity compressor capable of changing the rotational speed of the compression mechanism.
- the compression element (C) performs two-stage compression.
- the first compressor ( 21 ) that is a high-stage compressor constitutes a first compression section.
- the second and third compressors ( 22 ) and ( 23 ) that are low-stage compressors constitute a second compression section.
- a first suction pipe ( 21 a ) and a first discharge pipe ( 21 b ) are connected to the first compressor ( 21 ).
- a second suction pipe ( 22 a ) and a second discharge pipe ( 22 b ) are connected to the second compressor ( 22 ).
- a third suction pipe ( 23 a ) and a third discharge pipe ( 23 b ) are connected to the third compressor ( 23 ).
- the second and third discharge pipes ( 22 b ) and ( 23 b ) are connected to the first suction pipe ( 21 a ).
- the second suction pipe ( 22 a ) is connected through a pipe to the first gas-side trunk pipe ( 5 a ) of the second gas connection pipe ( 5 ).
- the second compressor ( 22 ) communicates with the refrigeration-facility units ( 60 ) through the second gas connection pipe ( 5 ).
- the second compressor ( 22 ) is a refrigeration-facility compressor associated with the refrigeration-facility units ( 60 ).
- the third suction pipe ( 23 a ) communicates with the air-conditioning units ( 50 ).
- the third compressor ( 23 ) is an indoor-side compressor associated with the air-conditioning units ( 50 ).
- the compression element (C) includes a second bypass pipe ( 24 b ) and a third bypass pipe ( 24 c ).
- the second bypass pipe ( 24 b ) is a pipe through which the refrigerant is passed while bypassing the second compressor ( 22 ).
- the second bypass pipe ( 24 b ) has two ends respectively connected to the second suction pipe ( 22 a ) and the second discharge pipe ( 22 b ).
- the third bypass pipe ( 24 c ) is a pipe through which the refrigerant is passed while bypassing the third compressor ( 23 ).
- the third bypass pipe ( 24 c ) has two ends respectively connected to the third suction pipe ( 23 a ) and the third discharge pipe ( 23 b ).
- the flow path switching mechanism ( 30 ) selects one of paths through which the refrigerant flows in the refrigerant circuit ( 6 ).
- the flow path switching mechanism ( 30 ) includes a first pipe ( 31 ), a second pipe ( 32 ), a third pipe ( 33 ), a fourth pipe ( 34 ), a first three-way valve (TV 1 ), and a second three-way valve (TV 2 ).
- the inflow end of the first pipe ( 31 ) and the inflow end of the second pipe ( 32 ) are connected to the first discharge pipe ( 21 b ).
- the first pipe ( 31 ) and the second pipe ( 32 ) are pipes on which the discharge pressure of the compression element (C) acts.
- the outflow end of the third pipe ( 33 ) and the outflow end of the fourth pipe ( 34 ) are connected to the third suction pipe ( 23 a ) of the third compressor ( 23 ).
- the third pipe ( 33 ) and the fourth pipe ( 34 ) are pipes on which the suction pressure of the compression element (C) acts.
- the first three-way valve (TV 1 ) has a first port (P 1 ), a second port (P 2 ), and a third port (P 3 ).
- the first port (P 1 ) of the first three-way valve (TV 1 ) is connected to the outflow end of the first pipe ( 31 ) that is a high-pressure flow path.
- the second port (P 2 ) of the first three-way valve (TV 1 ) is connected to the inflow end of the third pipe ( 33 ) that is a low-pressure flow path.
- the third port (P 3 ) of the first three-way valve (TV 1 ) is connected to one end of an indoor gas-side flow path ( 35 ).
- the other end of the indoor gas-side flow path ( 35 ) is connected to the first gas connection pipe ( 3 ).
- the second three-way valve (TV 2 ) has a first port (P 1 ), a second port (P 2 ), and a third port (P 3 ).
- the first port (P 1 ) of the second three-way valve (TV 2 ) is connected to the outflow end of the second pipe ( 32 ) that is a high-pressure flow path.
- the second port (P 2 ) of the second three-way valve (TV 2 ) is connected to the inflow end of the fourth pipe ( 34 ) that is a low-pressure flow path.
- the third port (P 3 ) of the second three-way valve (TV 2 ) is connected to an outdoor gas-side flow path ( 36 ).
- the first three-way valve (TV 1 ) and the second three-way valve (TV 2 ) are each an electric three-way valve.
- the three-way valves (TV 1 , TV 2 ) are each switched between the first state (the state indicated by a solid line in FIG. 1 ) and the second state (the state indicated by a dashed line in FIG. 1 ).
- the first port (P 1 ) and the third port (P 3 ) communicate with each other, and the second port (P 2 ) is closed.
- the second port (P 2 ) and the third port (P 3 ) communicate with each other, and the first port (P 1 ) is closed.
- the outdoor heat exchanger ( 13 ) constitutes a heat-source-side heat exchanger.
- the outdoor heat exchanger ( 13 ) is a fin-and-tube air heat exchanger.
- the outdoor fan ( 12 ) is disposed near the outdoor heat exchanger ( 13 ).
- the outdoor fan ( 12 ) transfers outdoor air.
- the outdoor heat exchanger exchanges heat between a refrigerant flowing therethrough and outdoor air transferred from the outdoor fan ( 12 ).
- the gas end of the outdoor heat exchanger ( 13 ) is connected to the outdoor gas-side flow path ( 36 ).
- the liquid end of the outdoor heat exchanger ( 13 ) is connected to an outdoor flow path (O).
- the outdoor flow path (O) includes a first outdoor pipe (o 1 ), a second outdoor pipe (o 2 ), a third outdoor pipe (o 3 ), a fourth outdoor pipe (o 4 ), a fifth outdoor pipe (o 5 ), a sixth outdoor pipe (o 6 ), a seventh outdoor pipe (o 7 ), and an eighth outdoor pipe (o 8 ).
- One end of the first outdoor pipe (o 1 ) is connected to the liquid end of the outdoor heat exchanger ( 13 ).
- the other end of the first outdoor pipe (o 1 ) is connected to one end of the second outdoor pipe (o 2 ) and one end of the third outdoor pipe (o 3 ).
- the other end of the second outdoor pipe (o 2 ) is connected to the top of the gas-liquid separator ( 15 ).
- One end of the fourth outdoor pipe (o 4 ) is connected to the bottom of the gas-liquid separator ( 15 ).
- the other end of the fourth outdoor pipe (o 4 ) is connected to one end of the fifth outdoor pipe (o 5 ) and the other end of the third outdoor pipe (o 3 ).
- the other end of the fifth outdoor pipe (o 5 ) is connected to one end of the sixth outdoor pipe (o 6 ) and one end of the eighth outdoor pipe (o 8 ).
- the other end of the eighth outdoor pipe (o 8 ) is connected to the first liquid-side trunk pipe ( 4 a ) of the second liquid connection pipe ( 4 ).
- the eighth outdoor pipe (o 8 ) is a liquid pipe through which a liquid refrigerant downstream of the gas-liquid separator ( 15 ) flows.
- the other end of the sixth outdoor pipe (o 6 ) is connected to the first liquid connection pipe ( 2 ).
- One end of the seventh outdoor pipe (o 7 ) is connected to an intermediate portion of the sixth outdoor pipe (o 6 ).
- the other end of the seventh outdoor pipe (o 7 ) is connected to an intermediate portion of the second outdoor pipe (o 2 ).
- the first outdoor pipe (o 1 ) of the outdoor circuit ( 11 ) is provided with an outdoor expansion valve ( 14 ).
- the outdoor expansion valve ( 14 ) is an electronic expansion valve that has its opening degree adjusted by a pulse motor driven in response to a pulse signal from the main controller ( 100 ).
- the gas-liquid separator ( 15 ) constitutes a container that stores the refrigerant.
- the gas-liquid separator ( 15 ) is provided downstream of the outdoor expansion valve ( 14 ).
- the refrigerant is separated into a gas refrigerant and a liquid refrigerant.
- the top of the gas-liquid separator ( 15 ) is connected to the other end of the second outdoor pipe (o 2 ) and one end of a venting pipe ( 37 ), which will be described below.
- the outdoor circuit ( 11 ) includes an intermediate injection circuit ( 49 ).
- the intermediate injection circuit ( 49 ) is a circuit through which the refrigerant decompressed by a decompression valve ( 40 ) is supplied to an intermediate pressure section of the compression element (C) between the first compression section ( 21 ) and the second compression section ( 22 , 23 ).
- the intermediate injection circuit ( 49 ) includes the venting pipe ( 37 ) and an injection pipe ( 38 ).
- the injection pipe ( 38 ) is connected to an intermediate portion of the fifth outdoor pipe (o 5 ).
- the other end of the injection pipe ( 38 ) is connected to the first suction pipe ( 21 a ) of the first compressor ( 21 ).
- the injection pipe ( 38 ) is provided with the decompression valve ( 40 ).
- the decompression valve ( 40 ) is an expansion valve having a variable opening degree.
- the venting pipe ( 37 ) is configured to allow the gas refrigerant in the gas-liquid separator ( 15 ) to flow out of the gas-liquid separator ( 15 ) into a flow path between the first compression section ( 21 ) and the second compression section ( 22 , 23 ). Specifically, one end of the venting pipe ( 37 ) is connected to the top of the gas-liquid separator ( 15 ). The other end of the venting pipe ( 37 ) is connected to an intermediate portion of the injection pipe ( 38 ). The venting pipe ( 37 ) is connected to a venting valve ( 39 ).
- the venting valve ( 39 ) is an electronic expansion valve having a variable opening degree.
- the outdoor circuit ( 11 ) includes the subcooling heat exchanger ( 16 ).
- the subcooling heat exchanger ( 16 ) is a cooling heat exchanger configured to cool the refrigerant (mainly the liquid refrigerant) separated in the gas-liquid separator ( 15 ).
- the subcooling heat exchanger ( 16 ) is connected between the gas-liquid separator ( 15 ) and a first valve ( 18 ).
- the subcooling heat exchanger ( 16 ) has a first flow path ( 16 a ) serving as a high-pressure flow path and a second flow path ( 16 b ) serving as a low-pressure flow path. In the subcooling heat exchanger ( 16 ), heat exchange occurs between the high-pressure refrigerant flowing through the first flow path ( 16 a ) and the decompressed refrigerant flowing through the second flow path ( 16 b ).
- the refrigerant flowing through the first flow path ( 16 a ) is cooled in the subcooling heat exchanger ( 16 ).
- the first flow path ( 16 a ) is connected to an intermediate portion of the fourth outdoor pipe (o 4 ) serving as a liquid pipe through which the liquid refrigerant in the outdoor circuit ( 11 ) flows.
- the second flow path ( 16 b ) is a flow path through which the refrigerant serving to cool the refrigerant flowing through the first flow path ( 16 a ) flows.
- the second flow path ( 16 b ) is included in the intermediate injection circuit ( 49 ). Specifically, the second flow path ( 16 b ) is connected to a portion of the injection pipe ( 38 ) downstream of the decompression valve ( 40 ). The refrigerant that has been decompressed at the decompression valve ( 40 ) flows through the second flow path ( 16 b ).
- the intercooler ( 17 ) is connected to an intermediate flow path ( 41 ).
- One end of the intermediate flow path ( 41 ) is connected to the second discharge pipe ( 22 b ) of the second compressor ( 22 ) and the third discharge pipe ( 23 b ) of the third compressor ( 23 ).
- the other end of the intermediate flow path ( 41 ) is connected to the first suction pipe ( 21 a ) of the first compressor ( 21 ).
- the other end of the intermediate flow path ( 41 ) is connected to the intermediate pressure section of the compression element (C).
- the intercooler ( 17 ) is a fin-and-tube air heat exchanger.
- a cooling fan ( 17 a ) is disposed near the intercooler ( 17 ).
- the intercooler ( 17 ) exchanges heat between the refrigerant flowing therethrough and the outdoor air transferred from the cooling fan ( 17 a ).
- the outdoor circuit ( 11 ) includes an oil separation circuit ( 42 ).
- the oil separation circuit ( 42 ) includes an oil separator ( 43 ), a first oil return pipe ( 44 ), a second oil return pipe ( 45 ), and a third oil return pipe ( 46 ).
- the oil separator ( 43 ) is connected to the first discharge pipe ( 21 b ) of the first compressor ( 21 ).
- the oil separator ( 43 ) separates oil from the refrigerant discharged from the compression element (C).
- the inflow end of the first oil return pipe ( 44 ) communicates with the oil separator ( 43 ).
- the outflow end of the first oil return pipe ( 44 ) is connected to the second suction pipe ( 22 a ) of the second compressor ( 22 ).
- the inflow end of the second oil return pipe ( 45 ) communicates with the oil separator ( 43 ).
- the outflow end of the second oil return pipe ( 45 ) is connected to the inflow end of the intermediate flow path ( 41 ).
- the third oil return pipe ( 46 ) includes a main return pipe ( 46 a ), a refrigeration-facility-side branch pipe ( 46 b ), and an indoor-side branch pipe ( 46 c ).
- the inflow end of the main return pipe ( 46 a ) communicates with the oil separator ( 43 ).
- the outflow end of the main return pipe ( 46 a ) is connected to the inflow end of the refrigeration-facility-side branch pipe ( 46 b ) and the inflow end of the indoor-side branch pipe ( 46 c ).
- the outflow end of the refrigeration-facility-side branch pipe ( 46 b ) communicates with an oil reservoir inside a casing of the second compressor ( 22 ).
- the outflow end of the indoor-side branch pipe ( 46 c ) communicates with an oil reservoir inside a casing of the third compressor ( 23 ).
- the first oil return pipe ( 44 ) is connected to a first oil level control valve ( 47 a ).
- the second oil return pipe ( 45 ) is connected to a second oil level control valve ( 47 b ).
- the refrigeration-facility-side branch pipe ( 46 b ) is connected to a third oil level control valve ( 47 c ).
- the indoor-side branch pipe ( 46 c ) is connected to a fourth oil level control valve ( 47 d ).
- a portion of oil separated in the oil separator ( 43 ) returns to the second compressor ( 22 ) via the first oil return pipe ( 44 ). Another portion of the oil separated in the oil separator ( 43 ) returns to the third compressor ( 23 ) via the second oil return pipe ( 45 ). The remaining portion of the oil separated in the oil separator ( 43 ) returns to the oil reservoir in the casing of each of the second compressor ( 22 ) and the third compressor ( 23 ) via the third oil return pipe ( 46 ).
- the outdoor circuit ( 11 ) has a first check valve (CV 1 ), a second check valve (CV 2 ), a third check valve (CV 3 ), a fourth check valve (CV 4 ), a fifth check valve (CV 5 ), a sixth check valve (CV 6 ), a seventh check valve (CV 7 ), an eighth check valve (CV 8 ), and a ninth check valve (CV 9 ).
- Each of these check valves (CV 1 to CV 9 ) allows the refrigerant to flow in the direction of the associated arrow shown in FIG. 1 and prohibits the refrigerant to flow in the opposite direction.
- the first check valve (CV 1 ) is connected to the first discharge pipe ( 21 b ).
- the second check valve (CV 2 ) is connected to the second discharge pipe ( 22 b ).
- the third check valve (CV 3 ) is connected to the third discharge pipe ( 23 b ).
- the fourth check valve (CV 4 ) is connected to the second outdoor pipe (o 2 ).
- the fifth check valve (CV 5 ) is connected to the third outdoor pipe (o 3 ).
- the sixth check valve (CV 6 ) is connected to the sixth outdoor pipe (o 6 ).
- the seventh check valve (CV 7 ) is connected to the seventh outdoor pipe (o 7 ).
- the eighth check valve (CV 8 ) is connected to the second bypass pipe ( 24 b ).
- the ninth check valve (CV 9 ) is connected to the third bypass pipe ( 24 c ).
- the heat source unit ( 10 ) includes various sensors.
- the sensors include a high-pressure sensor ( 71 ), an intermediate-pressure sensor ( 72 ), a first low-pressure sensor ( 73 ), a second low-pressure sensor ( 74 ), and a liquid refrigerant pressure sensor ( 75 ).
- the high-pressure sensor ( 71 ) detects the pressure of the refrigerant (the pressure (HP) of a high-pressure refrigerant) discharged from the first compressor ( 21 ).
- the intermediate-pressure sensor ( 72 ) detects the pressure of the refrigerant in the intermediate flow path ( 41 ), i.e., the pressure of the refrigerant between the first compressor ( 21 ) and a pair of the second and third compressors ( 22 ) and ( 23 ) (the pressure (MP) of an intermediate-pressure refrigerant).
- the first low-pressure sensor ( 73 ) detects the pressure of the refrigerant (the pressure (LP 1 ) of a first low-pressure refrigerant) to be sucked by the second compressor ( 22 ).
- the second low-pressure sensor ( 74 ) detects the pressure of the refrigerant (the pressure (LP 2 ) of a second low-pressure refrigerant) to be sucked by the third compressor ( 23 ).
- the liquid refrigerant pressure sensor ( 75 ) detects the pressure of the liquid refrigerant (the pressure (RP) of the liquid refrigerant) in the gas-liquid separator ( 15 ).
- the air-conditioning units ( 50 ) are utilization units installed indoors.
- the air-conditioning units ( 50 ) each condition air in an indoor space.
- the air-conditioning units ( 50 ) each include an indoor fan ( 52 ) and an indoor circuit ( 51 ).
- the liquid end of the indoor circuit ( 51 ) is connected to the first liquid connection pipe ( 2 ).
- the gas end of the indoor circuit ( 51 ) is connected to the first gas connection pipe ( 3 ).
- the indoor circuit ( 51 ) includes an indoor expansion valve ( 53 ) and an indoor heat exchanger ( 54 ) in order from the liquid end to the gas end.
- the indoor expansion valve ( 53 ) is a first utilization expansion valve.
- the indoor expansion valve ( 53 ) is an electronic expansion valve having a variable opening degree.
- the indoor heat exchanger ( 54 ) is a fin-and-tube air heat exchanger.
- the indoor fan ( 52 ) is disposed near the indoor heat exchanger ( 54 ).
- the indoor fan ( 52 ) transfers indoor air.
- the indoor heat exchanger ( 54 ) exchanges heat between a refrigerant flowing therethrough and indoor air transferred from the indoor fan ( 52 ).
- the air-conditioning units ( 50 ) each include an indoor controller ( 102 ). Although not shown, the air-conditioning units ( 50 ) each include a plurality of temperature sensors.
- the temperature sensors of each air-conditioning unit ( 50 ) include a sensor configured to measure the temperature of indoor air and a sensor configured to measure the temperature of the refrigerant flowing through the indoor circuit ( 51 ).
- the main controller ( 100 ) includes an outdoor controller ( 101 ) for the heat source unit ( 10 ) and the indoor controllers ( 102 ) for the respective air-conditioning units ( 50 ).
- the outdoor controller ( 101 ) and each of the indoor controllers ( 102 ) forming the main controller ( 100 ) are connected together through a communication line to be capable of communicating with each other.
- the outdoor controller ( 101 ) and the indoor controllers ( 102 ) each include a microcomputer mounted on a control board, and a memory device (specifically, a semiconductor memory) storing software for operating the microcomputer.
- the main controller ( 100 ) controls various components of the refrigeration apparatus ( 1 ) based on detection signals of the various sensors.
- the outdoor controller ( 101 ) controls the compression element (C) so that a value measured by the high-pressure sensor ( 71 ) (the pressure (HP) of the high-pressure refrigerant) is greater than or equal to the critical pressure of the refrigerant (in the present embodiment, carbon dioxide).
- the outdoor controller ( 101 ) controls the outdoor expansion valve ( 14 ) so that the refrigerant pressure in the gas-liquid separator ( 15 ) (specifically, a value measured by the liquid refrigerant pressure sensor ( 75 )) is less than the critical pressure of the refrigerant.
- the outdoor controller ( 101 ) controls the cooling capability of the subcooling heat exchanger ( 16 ). Specifically, the outdoor controller ( 101 ) controls the decompression valve ( 40 ) so that the refrigerant flowing out of the subcooling heat exchanger ( 16 ) is subcooled.
- the indoor controllers ( 102 ) each control the operation of the associated air-conditioning unit ( 50 ) so that the temperature of air sucked into the associated air-conditioning unit ( 50 ) becomes equal to a set temperature. Specifically, the indoor controllers ( 102 ) each control the associated indoor expansion valve ( 53 ) and the associated indoor fan ( 52 ).
- the refrigeration-facility units ( 60 ) are each, for example, a refrigerated show case installed in a store, such as a convenience store. Each refrigeration-facility unit ( 60 ) is a utilization unit that is installed indoors to cool air in the show case (inside air).
- the refrigeration-facility unit ( 60 ) includes a refrigeration-facility fan ( 62 ) and a refrigeration-facility circuit ( 61 ).
- the liquid end of the refrigeration-facility circuit ( 61 ) is connected to the associated liquid-side branch pipe ( 4 c ) of the second liquid connection pipe ( 4 ).
- the gas end of the refrigeration-facility circuit ( 61 ) is connected to the associated gas-side branch pipe ( 5 c ) of the second gas connection pipe ( 5 ).
- the refrigeration-facility circuit ( 61 ) includes a refrigeration-facility expansion valve ( 63 ) and a refrigeration-facility heat exchanger ( 64 ) in order from the liquid end to the gas end.
- the refrigeration-facility expansion valve ( 63 ) is configured as an electronic expansion valve having a variable opening degree.
- the refrigeration-facility heat exchanger ( 64 ) is a fin-and-tube air heat exchanger.
- the refrigeration-facility fan ( 62 ) is disposed near the refrigeration-facility heat exchanger ( 64 ).
- the refrigeration-facility fan ( 62 ) transfers inside air.
- the refrigeration-facility heat exchanger ( 64 ) exchanges heat between the refrigerant flowing therethrough and inside air transferred from the refrigeration-facility fan ( 62 ).
- the refrigeration-facility units ( 60 ) each include a refrigeration-facility controller ( 103 ). Although not shown, the refrigeration-facility units ( 60 ) each include a plurality of temperature sensors.
- the temperature sensors of each refrigeration-facility unit ( 60 ) include a sensor configured to measure the temperature of inside air and a sensor configured to measure the temperature of the refrigerant flowing through the refrigeration-facility circuit ( 61 ).
- the refrigeration-facility controllers ( 103 ) each include a microcomputer mounted on a control board, and a memory device (specifically, a semiconductor memory) storing software for operating the microcomputer.
- the refrigeration-facility controllers ( 103 ) do not communicate with the outdoor controller ( 101 ) and the indoor controllers ( 102 ).
- Each refrigeration-facility controller ( 103 ) controls the associated refrigeration-facility expansion valve ( 63 ) and the associated refrigeration-facility fan ( 62 ) based on detection signals of the various sensors.
- the refrigeration-facility controller ( 103 ) adjusts the opening degree of the associated refrigeration-facility expansion valve ( 63 ) so that the degree of superheat of the refrigerant at the outlet of the associated refrigeration-facility heat exchanger ( 64 ) functioning as an evaporator becomes equal to a predetermined target value. If the temperature of inside air falls within a set temperature range, the refrigeration-facility controller ( 103 ) allows a cooling operation of the associated refrigeration-facility unit ( 60 ) to be suspended. In this cooling-suspended state, while the refrigeration-facility fan ( 62 ) operates, the refrigeration-facility expansion valve ( 63 ) is closed.
- the intermediate unit ( 80 ) is separate from the heat source unit ( 10 ), the air-conditioning units ( 50 ), and the refrigeration-facility units ( 60 ).
- the intermediate unit ( 80 ) includes a liquid-side pipe ( 81 ), a gas-side pipe ( 82 ), and a joint pipe ( 83 ).
- the intermediate unit ( 80 ) includes a casing that houses the liquid-side pipe ( 81 ), the gas-side pipe ( 82 ), and the joint pipe ( 83 ).
- the intermediate unit ( 80 ) is installed indoors together with the refrigeration-facility units ( 60 ).
- liquid-side pipe ( 81 ) One end of the liquid-side pipe ( 81 ) is connected to the first liquid-side trunk pipe ( 4 a ) of the second liquid connection pipe ( 4 ), and the other end thereof is connected to the second liquid-side trunk pipe ( 4 b ) of the second liquid connection pipe ( 4 ).
- the liquid-side pipe ( 81 ) is connected to the liquid-side trunk pipes ( 4 a , 4 b ) of the second liquid connection pipe ( 4 ) connecting the heat source unit ( 10 ) and the refrigeration-facility units ( 60 ) together.
- the liquid-side pipe ( 81 ) is provided with the first valve ( 18 ) and a refrigerant pressure sensor ( 48 ) in order from the one end to the other end thereof.
- the refrigerant pressure sensor ( 48 ) is disposed in a portion of the liquid-side pipe ( 81 ) closer to the refrigeration-facility units ( 60 ) than the first valve ( 18 ) is.
- the first valve ( 18 ) is a control valve having a variable opening degree.
- the first valve ( 18 ) of the present embodiment is an electronic expansion valve including a pulse motor that drives its valve body.
- the refrigerant pressure sensor ( 48 ) measures the pressure of the refrigerant flowing through the liquid-side pipe ( 81 ). A value measured by the refrigerant pressure sensor ( 48 ) is substantially equal to the pressure of the refrigerant flowing through the liquid-side pipe ( 81 ) into the second liquid-side trunk pipe ( 4 b ).
- One end of the gas-side pipe ( 82 ) is connected to the first gas-side trunk pipe ( 5 a ) of the second gas connection pipe ( 5 ), and the other end thereof is connected to the second gas-side trunk pipe ( 5 b ) of the second gas connection pipe ( 5 ).
- the gas-side pipe ( 82 ) is connected to the gas-side trunk pipes ( 5 a , 5 b ) of the second gas connection pipe ( 5 ) connecting the heat source unit ( 10 ) and the refrigeration-facility units ( 60 ) together.
- One end of the joint pipe ( 83 ) is connected to the liquid-side pipe ( 81 ), and the other end thereof is connected to the gas-side pipe ( 82 ).
- the one end of the join pipe ( 83 ) is connected to a portion of the liquid-side pipe ( 81 ) closer to the second liquid-side trunk pipe ( 4 b ) than the first valve ( 18 ) is.
- the one end of the join pipe ( 83 ) of the present embodiment is connected to a portion of the liquid-side pipe ( 81 ) closer to the second liquid-side trunk pipe ( 4 b ) than the refrigerant pressure sensor ( 48 ) is.
- the one end of the joint pipe ( 83 ) may be connected to a portion of the liquid-side pipe ( 81 ) between the first valve ( 18 ) and the refrigerant pressure sensor ( 48 ).
- the joint pipe ( 83 ) is provided with a second valve ( 19 ).
- the second valve ( 19 ) is a control valve having a variable opening degree.
- the second valve ( 19 ) of the present embodiment is an electronic expansion valve including a pulse motor that drives its valve body.
- the intermediate unit ( 80 ) includes a hydraulic pressure controller ( 85 ).
- the hydraulic pressure controller ( 85 ) is connected to the first valve ( 18 ), the second valve ( 19 ), and the refrigerant pressure sensor ( 48 ) via communication lines.
- the hydraulic pressure controller ( 85 ) controls the first and second valves ( 18 ) and ( 19 ) based on the value measured by the refrigerant pressure sensor ( 48 ).
- the hydraulic pressure controller ( 85 ) includes a microcomputer mounted on a control board, and a memory device (specifically, a semiconductor memory) storing software for operating the microcomputer.
- the hydraulic pressure controller ( 85 ) does not communicate with the outdoor controller ( 101 ), the indoor controllers ( 102 ), and the refrigeration-facility controllers ( 103 ).
- the refrigeration apparatus ( 1 ) can perform a cooling operation and a heating operation.
- the cooling operation is an operation in which the air-conditioning units ( 50 ) cool the respective indoor spaces.
- the heating operation is an operation in which the air-conditioning units ( 50 ) heat the respective indoor spaces.
- the refrigeration-facility units ( 60 ) are each either in an active state or in the cooling-suspended state.
- the cooling operation of the refrigeration apparatus ( 1 ) will be described with reference to FIG. 3 .
- the cooling operation will be hereinafter described using an example in which the refrigeration-facility units ( 60 ) are in the active state.
- the refrigerant circuit ( 6 ) allows the refrigerant to circulate therethrough to perform a refrigeration cycle.
- the outdoor heat exchanger ( 13 ) functions as a radiator (a gas cooler), and the refrigeration-facility heat exchangers ( 64 ) and the indoor heat exchangers ( 54 ) function as evaporators.
- the first three-way valve (TV 1 ) is set in the second state
- the second three-way valve (TV 2 ) is set in the first state.
- the outdoor expansion valve ( 14 ), the refrigeration-facility expansion valves ( 63 ), the indoor expansion valves ( 53 ), the decompression valve ( 40 ), and the first valve ( 18 ) have their opening degrees adjusted as appropriate.
- the outdoor fan ( 12 ), the cooling fan ( 17 a ), the refrigeration-facility fans ( 62 ), and the indoor fans ( 52 ) operate.
- the first, second, and third compressors ( 21 ), ( 22 ), and ( 23 ) operate.
- the refrigerant that has been compressed in each of the second and third compressors ( 22 ) and ( 23 ) dissipates heat to outdoor air in the intercooler ( 17 ), and is then sucked into the first compressor ( 21 ).
- the refrigerant that has been compressed in the first compressor ( 21 ) dissipates heat to outdoor air in the outdoor heat exchanger ( 13 ), and is then decompressed while passing through the outdoor expansion valve ( 14 ).
- the decompressed refrigerant has a pressure that is lower than a second pressure (critical pressure).
- This refrigerant passes through the gas-liquid separator ( 15 ), and is then cooled in the subcooling heat exchanger ( 16 ).
- a portion of the refrigerant that has been cooled in the subcooling heat exchanger ( 16 ) flows into the eighth outdoor pipe (o 8 ), and the remaining portion thereof flows into the sixth outdoor pipe (o 6 ).
- the refrigerant that has flowed into the sixth outdoor pipe (o 6 ) flows through the first liquid connection pipe ( 2 ), and is distributed among the plurality of air-conditioning units ( 50 ).
- each air-conditioning unit ( 50 ) the refrigerant that has flowed into the indoor circuit ( 51 ) is decompressed while passing through the indoor expansion valve ( 53 ), and then absorbs heat from the indoor air to evaporate in the indoor heat exchanger ( 54 ).
- the air-conditioning unit ( 50 ) blows the air cooled in the indoor heat exchanger ( 54 ) into the indoor space.
- the flows of the refrigerant that has flowed out of the indoor heat exchangers ( 54 ) of the air-conditioning units ( 50 ) enter the first gas connection pipe ( 3 ) to merge together. Thereafter, this refrigerant flows into the outdoor circuit ( 11 ), and is then sucked into the third compressor ( 23 ) so as to be again compressed.
- the refrigerant that has flowed into the eighth outdoor pipe (o 8 ) flows through the first liquid-side trunk pipe ( 4 a ) of the second liquid connection pipe ( 4 ) into the liquid-side pipe ( 81 ) of the intermediate unit ( 80 ).
- the refrigerant that has flowed into the liquid-side pipe ( 81 ) is decompressed while passing through the first valve ( 18 ), then passes through the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) of the second liquid connection pipe ( 4 ), and is distributed among the plurality of refrigeration-facility units ( 60 ).
- each refrigeration-facility unit ( 60 ) the refrigerant that has flowed into the refrigeration-facility circuit ( 61 ) is decompressed while passing through the refrigeration-facility expansion valve ( 63 ), and then absorbs heat from the inside air to evaporate in the refrigeration-facility heat exchanger ( 64 ).
- the refrigeration-facility unit ( 60 ) blows the air cooled in the refrigeration-facility heat exchanger ( 64 ) into a space inside the refrigeration-facility.
- the flows of the refrigerant that has flowed out of the refrigeration-facility heat exchangers ( 64 ) of the refrigeration-facility units ( 60 ) enter the second gas connection pipe ( 5 ) to merge together. Thereafter, this refrigerant flows into the gas-side pipe ( 82 ) of the intermediate unit ( 80 ), passes through the gas-side pipe ( 82 ), and then flows through the first gas-side trunk pipe ( 5 a ) into the outdoor circuit ( 11 ). Thereafter, the refrigerant is sucked into the second compressor ( 22 ) so as to be again compressed.
- the heating operation of the refrigeration apparatus ( 1 ) will be described with reference to FIG. 4 .
- the heating operation will be hereinafter described using an example in which the refrigeration-facility units ( 60 ) are in the active state.
- the refrigerant circuit ( 6 ) allows the refrigerant to circulate therethrough to perform a refrigeration cycle.
- the indoor heat exchangers ( 54 ) function as radiators (gas coolers), and the refrigeration-facility heat exchangers ( 64 ) and the outdoor heat exchanger ( 13 ) function as evaporators.
- the refrigeration apparatus ( 1 ) of the present embodiment is operable either in a mode in which the outdoor heat exchanger ( 13 ) functions as a radiator or in a mode in which the outdoor heat exchanger ( 13 ) is suspended.
- the first three-way valve (TV 1 ) is set in the first state
- the second three-way valve (TV 2 ) is set in the second state.
- the outdoor expansion valve ( 14 ), the refrigeration-facility expansion valves ( 63 ), the indoor expansion valves ( 53 ), the decompression valve ( 40 ), and the first valve ( 18 ) have their opening degrees adjusted as appropriate.
- the outdoor fan ( 12 ), the refrigeration-facility fans ( 62 ), and the indoor fans ( 52 ) operate, and the cooling fan ( 17 a ) is suspended.
- the first, second, and third compressors ( 21 ), ( 22 ), and ( 23 ) operate.
- each of the second and third compressors ( 22 ) and ( 23 ) passes through the intercooler ( 17 ), and is then sucked into the first compressor ( 21 ).
- the refrigerant that has been compressed in the first compressor ( 21 ) flows through the first gas connection pipe ( 3 ), and is distributed among the plurality of air-conditioning units ( 50 ).
- the refrigerant that has flowed into the indoor circuit ( 51 ) dissipates heat to the indoor air in the indoor heat exchanger ( 54 ), and then flows into the first liquid connection pipe ( 2 ) after passing through the indoor expansion valve ( 53 ).
- the air-conditioning unit ( 50 ) blows the air heated in the indoor heat exchanger ( 54 ) into the indoor space.
- the refrigerant that has flowed into the fifth outdoor pipe (o 5 ) then flows through the eighth outdoor pipe (o 8 ) and the first liquid-side trunk pipe ( 4 a ) of the second liquid connection pipe ( 4 ) in this order into the liquid-side pipe ( 81 ) of the intermediate unit ( 80 ).
- the refrigerant that has flowed into the liquid-side pipe ( 81 ) is decompressed while passing through the first valve ( 18 ), then passes through the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) of the second liquid connection pipe ( 4 ), and is distributed among the plurality of refrigeration-facility units ( 60 ).
- each refrigeration-facility unit ( 60 ) the refrigerant that has flowed into the refrigeration-facility circuit ( 61 ) is decompressed while passing through the refrigeration-facility expansion valve ( 63 ), and then absorbs heat from the inside air to evaporate in the refrigeration-facility heat exchanger ( 64 ).
- the refrigeration-facility unit ( 60 ) blows the air cooled in the refrigeration-facility heat exchanger ( 64 ) into a space inside the refrigeration-facility.
- the flows of the refrigerant that has flowed out of the refrigeration-facility heat exchangers ( 64 ) of the refrigeration-facility units ( 60 ) enter the second gas connection pipe ( 5 ) to merge together. Thereafter, this refrigerant flows into the gas-side pipe ( 82 ) of the intermediate unit ( 80 ), passes through the gas-side pipe ( 82 ), and then flows through the first gas-side trunk pipe ( 5 a ) into the outdoor circuit ( 11 ). Thereafter, the refrigerant is sucked into the second compressor ( 22 ) so as to be again compressed.
- the refrigerant that has flowed into the third outdoor pipe (o 3 ) is decompressed while passing through the outdoor expansion valve ( 14 ), then flows into the outdoor heat exchanger ( 13 ), and absorbs heat from the outdoor air to evaporate in the outdoor heat exchanger ( 13 ).
- the refrigerant that has flowed out of the outdoor heat exchanger ( 13 ) is sucked into the third compressor ( 23 ) so as to be again compressed.
- the associated refrigeration-facility unit ( 60 ) While there is no need to cool the inside air, the associated refrigeration-facility unit ( 60 ) is in the cooling-suspended state. Specifically, if the inside air sucked into each refrigeration-facility unit ( 60 ) has a temperature that falls below the lower limit of a predetermined target range, the refrigeration-facility controller ( 103 ) of the refrigeration-facility unit ( 60 ) closes the refrigeration-facility expansion valve ( 63 ) to change the state of the refrigeration-facility unit ( 60 ) from the active state to the cooling-suspended state. In this cooling-suspended state, the refrigeration-facility fan ( 62 ) keeps operating.
- the refrigeration-facility expansion valve ( 63 ) closed prevents the refrigerant from being supplied from the second liquid connection pipe ( 4 ) to the refrigeration-facility unit ( 60 ), thereby stopping the cooling of air in the refrigeration-facility heat exchanger ( 64 ).
- each refrigeration-facility unit ( 60 ) has a temperature that exceeds the upper limit of the predetermined target range
- the refrigeration-facility controller ( 103 ) opens the refrigeration-facility expansion valve ( 63 ) to change the state of the refrigeration-facility unit ( 60 ) from the cooling-suspended state to the active state. If the state of the refrigeration-facility unit ( 60 ) is changed from the cooling-suspended state to the active state, the cooling of air in the refrigeration-facility heat exchanger ( 64 ) is restarted.
- the refrigerant pressure in the second gas connection pipe ( 5 ) decreases.
- a value measured by the first low-pressure sensor ( 73 ) decreases. If the value measured by the first low-pressure sensor ( 73 ) thus falls below a predetermined first reference value, the outdoor controller ( 101 ) stops the second compressor ( 22 ).
- the outdoor controller ( 101 ) actuates the second compressor ( 22 ).
- the hydraulic pressure controller ( 85 ) controls the first and second valves ( 18 ) and ( 19 ) so that the refrigerant pressure in the refrigeration-facility circuit ( 61 ) of each refrigeration-facility unit ( 60 ) is kept at or below the refrigerant pressure that can be allowed by the refrigeration-facility circuit ( 61 ).
- the refrigerant pressure that can be allowed by the refrigeration-facility circuit ( 61 ) is the allowable pressure Pu of the refrigeration-facility unit ( 60 ).
- each refrigeration-facility unit ( 60 ) is in the active state, the value measured by the refrigerant pressure sensor ( 48 ) is slightly higher than the pressure of the refrigerant at the inlet of the refrigeration-facility circuit ( 61 ).
- the refrigerant has its pressure gradually reduced, while flowing through the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipe ( 4 c ).
- the hydraulic pressure controller ( 85 ) of the present embodiment controls the opening degrees of the first and second valves ( 18 ) and ( 19 ) so that the value Pk measured by the refrigerant pressure sensor ( 48 ) is lower than the allowable pressure Pu of the refrigeration-facility units ( 60 ), as will be described below.
- the hydraulic pressure controller ( 85 ) controlling the first and second valves ( 18 ) and ( 19 ) allows the pressure of the refrigerant flowing into the refrigeration-facility circuit ( 61 ) of each refrigeration-facility unit ( 60 ) to be kept below the allowable pressure Pu of the refrigeration-facility unit ( 60 ).
- the hydraulic pressure controller ( 85 ) repeatedly performs the control operation shown in the flowchart of FIG. 6 at predetermined time intervals (e.g., 30 seconds).
- the hydraulic pressure controller ( 85 ) reads the value Pk measured by the refrigerant pressure sensor ( 48 ), and compares the measured value Pk with a first reference pressure PL 1 .
- the first reference pressure PL 1 is lower than the allowable pressure Pu of the refrigeration-facility units ( 60 ) (PL 1 ⁇ Pu).
- the first reference pressure PL 1 of the present embodiment is 4.5 MPa.
- step ST 1 if the value Pk measured by the refrigerant pressure sensor ( 48 ) is less than or equal to the first reference pressure PL 1 (Pk ⁇ PL 1 ), the hydraulic pressure controller ( 85 ) performs a process in step ST 2 . On the other hand, if the value Pk measured by the refrigerant pressure sensor ( 48 ) exceeds the first reference pressure PL 1 (Pk>PL 1 ), the hydraulic pressure controller ( 85 ) performs a process in step ST 3 .
- the hydraulic pressure controller ( 85 ) makes the first valve ( 18 ) fully open. In other words, in the process performed in step ST 2 , the hydraulic pressure controller ( 85 ) sets the opening degree of the first valve ( 18 ) at a maximum value.
- the hydraulic pressure controller ( 85 ) compares the value Pk measured by the refrigerant pressure sensor ( 48 ) with a second reference pressure PL 2 .
- the second reference pressure PL 2 is lower than the allowable pressure Pu of the refrigeration-facility units ( 60 ), and is higher than the first reference pressure PL 1 (PL 1 ⁇ PL 2 ⁇ Pu).
- the second reference pressure PL 2 of the present embodiment is 5.2 MPa.
- step ST 3 if the value Pk measured by the refrigerant pressure sensor ( 48 ) is greater than or equal to the second reference pressure PL 2 (PL 2 ⁇ Pk), the hydraulic pressure controller ( 85 ) performs a process in step ST 4 . On the other hand, if the value Pk measured by the refrigerant pressure sensor ( 48 ) falls below the second reference pressure PL 2 (Pk ⁇ PL 2 ), the hydraulic pressure controller ( 85 ) performs a process in step ST 5 .
- the hydraulic pressure controller ( 85 ) makes the first valve ( 18 ) fully closed. In other words, in the process performed in step ST 4 , the hydraulic pressure controller ( 85 ) sets the opening degree of the first valve ( 18 ) to be substantially zero.
- the hydraulic pressure controller ( 85 ) adjusts the opening degree of the first valve ( 18 ) in accordance with the value Pk measured by the refrigerant pressure sensor ( 48 ). Specifically, the hydraulic pressure controller ( 85 ) performs proportional-integral-derivation (PID) control to adjust the opening degree of the first valve ( 18 ) so that the value Pk measured by the refrigerant pressure sensor ( 48 ) becomes equal to a third reference pressure PL 3 .
- the third reference pressure PL 3 is greater than the first reference pressure PL 1 , and is less than the second reference pressure PL 2 (PL 1 ⁇ PL 3 ⁇ PL 2 ).
- the third reference pressure PL 3 of the present embodiment is 4.8 MPa. Note that the hydraulic pressure controller ( 85 ) may adjust the opening degree of the first valve ( 18 ) using a control system except the PID control.
- the hydraulic pressure controller ( 85 ) adjusts the opening degree of the first valve ( 18 ) so that the value Pk measured by the refrigerant pressure sensor ( 48 ) becomes less than or equal to the second reference pressure PL 2 .
- the pressure of the refrigerant to be supplied through the second liquid connection pipe ( 4 ) from the intermediate unit ( 80 ) to the refrigeration-facility units ( 60 ) in the active state is kept below the allowable pressure Pu of the refrigeration-facility units ( 60 ).
- the hydraulic pressure controller ( 85 ) reads the value Pk measured by the refrigerant pressure sensor ( 48 ) at predetermined time intervals (e.g., one second). The hydraulic pressure controller ( 85 ) sets the opening degree of the second valve ( 19 ) in accordance with the value Pk measured by the refrigerant pressure sensor ( 48 ).
- the hydraulic pressure controller ( 85 ) makes the second valve ( 19 ) fully closed. In other words, in this case, the hydraulic pressure controller ( 85 ) sets the opening degree of the second valve ( 19 ) to be substantially zero.
- the fourth reference pressure PL 4 is greater than the second reference pressure PL 2 , and is less than the allowable pressure Pu (PL 2 ⁇ PL 4 ⁇ Pu).
- the fourth reference pressure PL 4 of the present embodiment is 5.4 MPa.
- the hydraulic pressure controller ( 85 ) makes the second valve ( 19 ) fully open. In other words, in this case, the hydraulic pressure controller ( 85 ) sets the opening degree of the second valve ( 19 ) at a maximum value.
- the fifth reference pressure PL 5 is greater than the fourth reference pressure PL 4 , and is less than the allowable pressure Pu (PL 4 ⁇ PL 5 ⁇ Pu).
- the fifth reference pressure PL 5 of the present embodiment is 5.8 MPa.
- the hydraulic pressure controller ( 85 ) sets the opening degree of the second valve ( 19 ) to be a value proportional to the value Pk measured by the refrigerant pressure sensor ( 48 ).
- the hydraulic pressure controller ( 85 ) sets the opening degree of the second valve ( 19 ) at a maximum value.
- the hydraulic pressure controller ( 85 ) makes the first valve ( 18 ) fully closed.
- the fourth reference pressure PL 4 is higher than the second reference pressure PL 2 (PL 2 ⁇ PL 4 ).
- the hydraulic pressure controller ( 85 ) opens the second valve ( 19 ).
- the hydraulic pressure controller ( 85 ) adjusts the opening degree of the first valve ( 18 ) so that the value Pk measured by the refrigerant pressure sensor ( 48 ) becomes less than or equal to the second reference pressure PL 2 .
- the refrigerant pressure acting on the refrigeration-facility expansion valves ( 63 ) is kept below the allowable pressure Pu of the refrigeration-facility units ( 60 ).
- the associated refrigeration-facility controller ( 103 ) closes the associated refrigeration-facility expansion valve ( 63 ) to change the state of the associated refrigeration-facility unit ( 60 ) from the active state to the cooling-suspended state. If all of the refrigeration-facility units ( 60 ) are in the cooling-suspended state, the refrigerant pressure in the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) increases. As a result, the value Pk measured by the refrigerant pressure sensor ( 48 ) increases. If the value Pk measured by the refrigerant pressure sensor ( 48 ) then increases to a value greater than or equal to the second reference pressure PL 2 , the hydraulic pressure controller ( 85 ) closes the first valve ( 18 ).
- the pressure of the refrigerant enclosed in the portion of the refrigerant circuit ( 6 ) between the refrigeration-facility expansion valves ( 63 ) and the first valve ( 18 ) increases. This may cause the refrigerant pressure acting on the refrigeration-facility expansion valves ( 63 ) to exceed the allowable pressure Pu of the refrigeration-facility units ( 60 ) unless some countermeasure is taken.
- the hydraulic pressure controller ( 85 ) of the intermediate unit ( 80 ) of the present embodiment controls the opening degree of the second valve ( 19 ). Specifically, if the value Pk measured by the refrigerant pressure sensor ( 48 ) exceeds the fourth reference pressure PL 4 , the hydraulic pressure controller ( 85 ) opens the second valve ( 19 ).
- the open second valve ( 19 ) allows a portion of the refrigerant present in the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) to flow through the joint pipe ( 83 ) to the gas-side pipe ( 82 ) and the gas connection pipe ( 5 ).
- the refrigerant pressure in the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) decreases.
- the refrigerant pressure acting on the refrigeration-facility expansion valves ( 63 ) of the refrigeration-facility units ( 60 ) is kept below the allowable pressure Pu of the refrigeration-facility units ( 60 ).
- the second valve ( 19 ) opens when all of the refrigeration-facility units ( 60 ) are in the cooling-suspended state and the second compressor ( 22 ) is stopped. If the second valve ( 19 ) opens during operations of the first and third compressors ( 21 ) and ( 23 ), the refrigerant present in the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) is drawn by the first compressor ( 21 ).
- the refrigerant present in the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) flows through the joint pipe ( 83 ), the gas-side pipe ( 82 ), and the gas connection pipe ( 5 ) in this order into the outdoor circuit ( 11 ), and joins the refrigerant discharged from the third compressor ( 23 ) after passing through the second bypass pipe ( 24 b ).
- the resultant refrigerant is subsequently sucked into the first compressor ( 21 ) after passing through the intercooler ( 17 ).
- the hydraulic controller ( 85 ) opens the second valve ( 19 ) while all of the compressors ( 21 , 22 , 23 ) are stopped.
- the first compressor ( 21 ) may be started, and the refrigerant present in the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) may be drawn into the first compressor ( 21 ).
- This causes the refrigerant present in the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) to turn into the form of single-phase gas while passing through the intercooler ( 17 ), and to be then sucked into the first compressor ( 21 ).
- the intermediate unit ( 80 ) of the present embodiment is provided between the heat source unit ( 10 ) and the refrigeration-facility units ( 60 ), which are connected together through the liquid connection pipe ( 4 ) and the gas connection pipe ( 5 ) to form part of the refrigeration apparatus ( 1 ).
- the intermediate unit ( 80 ) includes the liquid-side pipe ( 81 ), the first valve ( 18 ), the refrigerant pressure sensor ( 48 ), and the hydraulic pressure controller ( 85 ).
- the liquid-side pipe ( 81 ) is connected to the liquid connection pipe ( 4 ).
- the first valve ( 18 ) is a valve provided for the liquid-side pipe ( 81 ) and having a variable opening degree.
- the refrigerant pressure sensor ( 48 ) is disposed in a portion of the liquid-side pipe ( 81 ) closer to the refrigeration-facility units ( 60 ) than the first valve ( 18 ) is, and measures the pressure of the refrigerant flowing through the liquid-side pipe ( 81 ).
- the hydraulic pressure controller ( 85 ) adjusts the opening degree of the first valve ( 18 ) based on the value measured by the refrigerant pressure sensor ( 48 ).
- the refrigerant sent out from the heat source unit ( 10 ) and flowing through the liquid connection pipe ( 4 ) is supplied to the refrigeration-facility units ( 60 ) after passing through the liquid-side pipe ( 81 ) of the intermediate unit ( 80 ).
- the hydraulic pressure controller ( 85 ) changing the opening degree of the first valve ( 18 ) for the liquid-side pipe ( 81 ) triggers a change in the pressure of the refrigerant that has passed through the first valve ( 18 ).
- the intermediate unit ( 80 ) adjusts the pressure of the refrigerant flowing into the refrigeration-facility units ( 60 ). For this reason, even if the heat source unit ( 10 ) does not perform control with consideration given to the allowable pressure of the refrigeration-facility units ( 60 ), the refrigeration-facility units ( 60 ) having an allowable pressure that is lower than that of the heat source unit ( 10 ) can be connected to the heat source unit ( 10 ). Thus, according to the present embodiment, various models of refrigeration-facility units can be connected to the heat source unit ( 10 ) without complicating the manner of control performed by the heat source unit ( 10 ).
- the intermediate unit ( 80 ) of the present embodiment includes the gas-side pipe ( 82 ), the joint pipe ( 83 ), and the second valve ( 19 ).
- the gas-side pipe ( 82 ) is connected to the gas connection pipe ( 5 ).
- the joint pipe ( 83 ) connects the portion of the liquid-side pipe ( 81 ) closer to the refrigeration-facility units ( 60 ) than the first valve ( 18 ) is and the gas-side pipe ( 82 ) together.
- the second valve ( 19 ) is provided for the joint pipe ( 83 ).
- the refrigeration-facility expansion valves ( 63 ) of the refrigeration-facility units ( 60 ) and the first valve ( 18 ) of the intermediate unit ( 80 ) are all closed, the refrigerant is enclosed in a portion of the liquid connection pipe ( 4 ) between the intermediate unit ( 80 ) and the refrigeration-facility units ( 60 ). If this state occurs while the air temperature around the liquid connection pipe ( 4 ) is high, the internal pressure of the liquid connection pipe ( 4 ) increases. This may damage the refrigeration-facility units ( 60 ).
- the intermediate unit ( 80 ) of the present embodiment includes the joint pipe ( 83 ) connecting the liquid-side pipe ( 81 ) and the gas-side pipe ( 82 ) together and provided with the second valve ( 19 ). While the second valve ( 19 ) is open, the portion of the liquid connection pipe ( 4 ) between the intermediate unit ( 80 ) and the refrigeration-facility units ( 60 ) communicates with the gas connection pipe ( 5 ) via the joint pipe ( 83 ).
- This can substantially prevent the internal pressure of the liquid connection pipe ( 4 ) from increasing excessively while the refrigeration-facility expansion valves ( 63 ) of the refrigeration-facility units ( 60 ) and the first valve ( 18 ) of the intermediate unit ( 80 ) are all closed. As a result, the refrigeration-facility units ( 60 ) can be substantially prevented from being damaged.
- the hydraulic pressure controller ( 85 ) adjusts the opening degree of the first valve ( 18 ) so that the value measured by the refrigerant pressure sensor ( 48 ) becomes less than or equal to the second reference pressure PL 2 . If the value measured by the refrigerant pressure sensor ( 48 ) exceeds “the fourth reference pressure PL 4 higher than the second reference pressure PL 2 ” even with the first valve ( 18 ) closed, the hydraulic pressure controller ( 85 ) opens the second valve ( 19 ).
- the hydraulic pressure controller ( 85 ) of the intermediate unit ( 80 ) of the present embodiment controls the first and second valves ( 18 ) and ( 19 ).
- the hydraulic pressure controller ( 85 ) controlling the first valve ( 18 ) allows the pressure of the refrigerant that is about to be supplied from the intermediate unit ( 80 ) to the refrigeration-facility units ( 60 ) to be substantially kept at or below the second reference pressure PL 2 .
- the hydraulic pressure controller ( 85 ) controlling the second valve ( 19 ) substantially prevents the internal pressure of the portion of the liquid connection pipe ( 4 ) between the intermediate unit ( 80 ) and the refrigeration-facility units ( 60 ) from increasing excessively even while the first valve ( 18 ) is closed.
- the intermediate unit ( 80 ) of the present embodiment is installed indoors, and is connected to the heat source unit ( 10 ) installed outdoors.
- the intermediate unit ( 80 ) of the present embodiment is placed indoors.
- the air temperature around the portion of the liquid connection pipe ( 4 ) between the intermediate unit ( 80 ) and the refrigeration-facility units ( 60 ) is lower than that outdoors.
- This can substantially prevent the internal pressure of the portion of the liquid connection pipe ( 4 ) between the intermediate unit ( 80 ) and the refrigeration-facility units ( 60 ) from increasing while the refrigeration-facility expansion valves ( 63 ) of the refrigeration-facility units ( 60 ) and the first valve ( 18 ) of the intermediate unit ( 80 ) are all closed.
- the intermediate unit ( 80 ) may be arranged in the indoor space where the refrigeration-facility units ( 60 ) are also arranged.
- the refrigeration-facility units ( 60 ) are typically installed in an indoor space to be air-conditioned by an air-conditioning unit ( 50 ). For example, even if the outdoor air temperature is relatively high in the summer, the air temperature in the indoor space including the intermediate unit ( 80 ) and the refrigeration-facility units ( 60 ) is lower than the outdoor air temperature.
- the intermediate unit ( 80 ) installed indoors could substantially prevent the internal pressure of the portion of the liquid connection pipe ( 4 ) between the intermediate unit ( 80 ) and the refrigeration-facility units ( 60 ) from increasing while the refrigeration-facility expansion valves ( 63 ) of the refrigeration-facility units ( 60 ) and the first valve ( 18 ) of the intermediate unit ( 80 ) are all closed.
- the refrigeration apparatus ( 1 ) of the present embodiment includes the intermediate unit ( 80 ), the heat source unit ( 10 ), the refrigeration-facility units ( 60 ), the liquid connection pipe ( 4 ), and the gas connection pipe ( 5 ).
- the liquid connection pipe ( 4 ) and the gas connection pipe ( 5 ) connect the intermediate unit ( 80 ), the heat source unit ( 10 ), and the refrigeration-facility units ( 60 ) together to form the refrigerant circuit ( 6 ).
- the intermediate unit ( 80 ) is disposed between the heat source unit ( 10 ) and the refrigeration-facility units ( 60 ) in the refrigerant circuit ( 6 ).
- the liquid-side pipe ( 81 ) of the intermediate unit ( 80 ) is connected to the liquid connection pipe ( 4 ). Changing the opening degree of the first valve ( 18 ) of the intermediate unit ( 80 ) triggers a change in the pressure of the refrigerant to be sent through the liquid connection pipe ( 4 ) from the intermediate unit ( 80 ) to the refrigeration-facility units ( 60 ).
- the refrigeration apparatus ( 1 ) of the present embodiment includes the intermediate unit ( 80 ), the heat source unit ( 10 ), the refrigeration-facility units ( 60 ), the liquid connection pipe ( 4 ), and the gas connection pipe ( 5 ).
- the liquid connection pipe ( 4 ) includes the liquid-side trunk pipes ( 4 a , 4 b ) connected to the heat source unit ( 10 ), and the plurality of liquid-side branch pipes ( 4 c ) each connecting an associated one of the refrigeration-facility units ( 60 ) to the liquid-side trunk pipes ( 4 a , 4 b ).
- the gas connection pipe ( 5 ) includes the gas-side trunk pipes ( 5 a , 5 b ) connected to the heat source unit ( 10 ), and the plurality of gas-side branch pipes ( 5 c ) each connecting an associated one of the refrigeration-facility units ( 60 ) to the gas-side trunk pipes ( 5 a , 5 b ).
- the liquid-side pipe ( 81 ) of the intermediate unit ( 80 ) is connected to the liquid-side trunk pipes ( 4 a , 4 b ) of the liquid connection pipe ( 4 ).
- the gas-side pipe ( 82 ) of the intermediate unit ( 80 ) is connected to the gas-side trunk pipes ( 5 a , 5 b ) of the gas connection pipe ( 5 ).
- the plurality of refrigeration-facility units ( 60 ) are connected through the liquid connection pipe ( 4 ) and the gas connection pipe ( 5 ) to the heat source unit ( 10 ).
- the intermediate unit ( 80 ) is connected to the liquid-side trunk pipes ( 4 a , 4 b ) of the liquid connection pipe ( 4 ) and the gas-side trunk pipes ( 5 a , 5 b ) of the gas connection pipe ( 5 ).
- the refrigerant that has flowed from the heat source unit ( 10 ) into the liquid-side trunk pipes ( 4 a , 4 b ) of the liquid connection pipe ( 4 ) passes through the first valve ( 18 ) of the intermediate unit ( 80 ), and is then distributed among the plurality of refrigeration-facility units ( 60 ).
- the second valve ( 19 ) of the intermediate unit ( 80 ) of the foregoing embodiment may be an on-off valve that selectively switches between the fully-closed state and the fully-open state.
- a second valve ( 19 ) of this variation is an electromagnetic valve including a solenoid that drives its valve body.
- a hydraulic pressure controller ( 85 ) of this variation changes the state of the second valve ( 19 ) from the fully-closed state to the fully-open state.
- the hydraulic pressure controller ( 85 ) of this variation changes the state of the second valve ( 19 ) from the fully-open state to the fully-closed state.
- the fourth and fifth reference pressures PL 4 and PL 5 are respectively equal to those set when the second valve ( 19 ) is a control valve having a variable opening degree.
- the hydraulic pressure controller ( 85 ) of the foregoing embodiment may set the fourth reference pressure PL 4 at a value slightly less than the second reference pressure PL 2 (PL 4 ⁇ PL 2 ). Even in such a case, the fourth reference pressure PL 4 is set at a value greater than the first reference pressure PL 1 (PL 1 ⁇ PL 4 ). It is possible for a second valve ( 19 ) of an intermediate unit ( 80 ) of this variation to start opening before the first valve ( 18 ) falls into the fully-closed state.
- the intermediate unit ( 80 ) of the foregoing embodiment may include a pressure input section ( 86 ).
- the pressure input section ( 86 ) is a member to be operated by an operator to input information on the allowable pressure Pu of the refrigeration-facility units ( 60 ) to the hydraulic pressure controller ( 85 ).
- Examples of the pressure input section ( 86 ) include a DIP switch and a numeric keypad for input of numerals.
- a pressure input section ( 86 ) of an intermediate unit ( 80 ) of this variation is electrically connected to a hydraulic pressure controller ( 85 ) via a communication line or any other similar element.
- Information input to the pressure input section ( 86 ) is transmitted to the hydraulic pressure controller ( 85 ), and is recorded in a memory device of the hydraulic pressure controller ( 85 ).
- Information to be input to the pressure input section ( 86 ) may include the allowable pressure Pu of the refrigeration-facility units ( 60 ) or a symbol such as a number corresponding to the allowable pressure Pu.
- the hydraulic pressure controller ( 85 ) of this variation sets the reference pressures PL 1 to PL 5 based on the information input to the pressure input section ( 86 ), and controls the opening degrees of the first and second valves ( 18 ) and ( 19 ) with reference to the set reference pressures PL 1 to PL 5 .
- the intermediate unit ( 80 ) of the foregoing embodiment may omit the gas-side pipe ( 82 ), the joint pipe ( 83 ), and the second valve ( 19 ).
- the refrigerant pressure in the second liquid-side trunk pipe ( 4 b ) and the liquid-side branch pipes ( 4 c ) may be kept at or below the allowable pressure of the refrigeration-facility units ( 60 ) even with the refrigeration-facility expansion valves ( 63 ) of all of the refrigeration-facility units ( 60 ) and the first valve ( 18 ) of the intermediate unit ( 80 ) closed.
- the intermediate unit ( 80 ) forming part of the refrigeration apparatus ( 1 ) installed in the cold climate area may omit the gas-side pipe ( 82 ), the joint pipe ( 83 ), and the second valve ( 19 ).
- An intermediate unit ( 80 ) of this variation is connected only to a liquid connection pipe ( 4 ) but is not connected to a gas connection pipe ( 5 ).
- the refrigeration apparatus ( 1 ) of the foregoing embodiment may omit the air-conditioning units ( 50 ) while including the heat source unit ( 10 ) and the refrigeration-facility units ( 60 ).
- a refrigeration apparatus ( 1 ) of this variation exclusively cools inside air.
- a heat source unit ( 10 ) forming part of the refrigeration apparatus ( 1 ) of this variation omits a third compressor ( 23 ).
- the utilization units of the refrigeration apparatus ( 1 ) of the foregoing embodiment are not limited to the air-conditioning units ( 50 ) configured to condition air in a room.
- the utilization units of the refrigeration apparatus ( 1 ) of the foregoing embodiment may be configured to heat or cool water using a refrigerant.
- a utilization unit of this variation includes a heat exchanger configured to exchange heat between a refrigerant and water, as a utilization heat exchanger.
- the present disclosure is useful for an intermediate unit for a refrigeration apparatus, and a refrigeration apparatus including the intermediate unit.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Fluid Mechanics (AREA)
- Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
- Air Conditioning Control Device (AREA)
- Other Air-Conditioning Systems (AREA)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2019-207898 | 2019-11-18 | ||
JP2019207898A JP6835184B1 (ja) | 2019-11-18 | 2019-11-18 | 冷凍装置用の中間ユニットおよび冷凍装置 |
PCT/JP2020/025138 WO2021100234A1 (ja) | 2019-11-18 | 2020-06-26 | 冷凍装置用の中間ユニットおよび冷凍装置 |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2020/025138 Continuation WO2021100234A1 (ja) | 2019-11-18 | 2020-06-26 | 冷凍装置用の中間ユニットおよび冷凍装置 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20220268498A1 true US20220268498A1 (en) | 2022-08-25 |
Family
ID=74661786
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/743,161 Pending US20220268498A1 (en) | 2019-11-18 | 2022-05-12 | Intermediate unit for refrigeration apparatus, and refrigeration apparatus |
Country Status (5)
Country | Link |
---|---|
US (1) | US20220268498A1 (de) |
EP (1) | EP4047289A4 (de) |
JP (1) | JP6835184B1 (de) |
CN (1) | CN114729767A (de) |
WO (1) | WO2021100234A1 (de) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN112902510A (zh) * | 2021-03-17 | 2021-06-04 | 常州市威硕自动化科技有限公司 | 基于温度值和湿度值的电子膨胀阀多段线性控制方法及系统 |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4089139B2 (ja) * | 2000-07-26 | 2008-05-28 | ダイキン工業株式会社 | 空気調和機 |
JP5949832B2 (ja) * | 2014-05-30 | 2016-07-13 | ダイキン工業株式会社 | 空調システム |
CN107709887B (zh) * | 2015-06-01 | 2020-03-03 | 三菱电机株式会社 | 空气调节装置以及运行控制装置 |
JP6621017B2 (ja) | 2016-02-02 | 2019-12-18 | パナソニックIpマネジメント株式会社 | 冷凍装置 |
WO2017179166A1 (ja) * | 2016-04-14 | 2017-10-19 | 三菱電機株式会社 | 空気調和装置 |
GB2567332B (en) * | 2016-07-27 | 2021-04-21 | Mitsubishi Electric Corp | Air conditioning apparatus |
US11268740B2 (en) * | 2016-09-30 | 2022-03-08 | Daikin Industries, Ltd. | Refrigeration apparatus |
-
2019
- 2019-11-18 JP JP2019207898A patent/JP6835184B1/ja active Active
-
2020
- 2020-06-26 CN CN202080080052.8A patent/CN114729767A/zh active Pending
- 2020-06-26 WO PCT/JP2020/025138 patent/WO2021100234A1/ja unknown
- 2020-06-26 EP EP20889034.3A patent/EP4047289A4/de not_active Withdrawn
-
2022
- 2022-05-12 US US17/743,161 patent/US20220268498A1/en active Pending
Also Published As
Publication number | Publication date |
---|---|
WO2021100234A1 (ja) | 2021-05-27 |
CN114729767A (zh) | 2022-07-08 |
EP4047289A1 (de) | 2022-08-24 |
JP2021081114A (ja) | 2021-05-27 |
EP4047289A4 (de) | 2022-12-21 |
JP6835184B1 (ja) | 2021-02-24 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8181480B2 (en) | Refrigeration device | |
US8176743B2 (en) | Refrigeration device | |
US8171747B2 (en) | Refrigeration device | |
JP7116346B2 (ja) | 熱源ユニット及び冷凍装置 | |
US11598559B2 (en) | Heat source-side unit and refrigeration apparatus | |
US11796238B2 (en) | Heat source unit and refrigeration apparatus | |
US20220221200A1 (en) | Refrigeration apparatus | |
US11448433B2 (en) | Refrigeration apparatus | |
US12031752B2 (en) | Refrigeration apparatus | |
US20220268498A1 (en) | Intermediate unit for refrigeration apparatus, and refrigeration apparatus | |
US12085320B2 (en) | Heat source unit and refrigeration apparatus | |
US11486616B2 (en) | Refrigeration device | |
US11573039B2 (en) | Heat source unit and refrigeration apparatus | |
CN114341569A (zh) | 热源机组及制冷装置 | |
US11512876B2 (en) | Refrigeration apparatus | |
US20240011671A1 (en) | Heat source unit and refrigeration apparatus | |
US11686518B2 (en) | Refrigeration apparatus that operates a utilization unit based on drivability of a compressor in a heat source unit | |
WO2024171705A1 (ja) | 熱源ユニットおよび冷凍装置 | |
WO2024171704A1 (ja) | 熱源ユニットおよび冷凍装置 | |
JP2022083173A (ja) | 熱源システムおよび冷凍装置 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: DAIKIN INDUSTRIES, LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TAKEGAMI, MASAAKI;UENO, AKITOSHI;TAGUCHI, SHUICHI;AND OTHERS;SIGNING DATES FROM 20211221 TO 20211222;REEL/FRAME:059901/0491 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |