EP1816416A1 - Air conditioner - Google Patents
Air conditioner Download PDFInfo
- Publication number
- EP1816416A1 EP1816416A1 EP05805432A EP05805432A EP1816416A1 EP 1816416 A1 EP1816416 A1 EP 1816416A1 EP 05805432 A EP05805432 A EP 05805432A EP 05805432 A EP05805432 A EP 05805432A EP 1816416 A1 EP1816416 A1 EP 1816416A1
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- EP
- European Patent Office
- Prior art keywords
- refrigerant
- connection
- heat exchanger
- connection end
- pipe
- 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.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
- F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
- F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/006—Compression machines, plants or systems with reversible cycle not otherwise provided for two pipes connecting the outdoor side to the indoor side with multiple indoor units
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- 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
- F25B2313/0231—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units with simultaneous cooling and heating
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- 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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- 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
- F25B2313/0272—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using bridge circuits of one-way valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- 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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/04—Refrigeration circuit bypassing means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/23—Separators
Definitions
- the present invention generally relates to an air conditioner applying a refrigeration cycle.
- the present invention relates to a multi-split type air conditioner including an outdoor unit and a plurality of indoor units, performing in operation modes where all of the rooms are cooled and heated, and in other operation modes where one of the rooms is cooled while another one of the rooms is heated, simultaneously.
- Patent Document 1 discloses a multi-split type air conditioner, which includes an outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units, each having an indoor heat exchanger, and a relay device for connection between the outdoor unit and the indoor units.
- the multi-split type air conditioner performs in the cooling and heating operation modes cooling and heating all of the rooms, respectively. Also, it performs in other operation modes cooling one of the rooms while heating another one of the rooms simultaneously, which are referred to as a principally-cooling operation mode where cooling operation capacity is greater than heating operation capacity, and as a principally-heating operation mode where heating operation capacity is greater than cooling operation capacity.
- the conventional air conditioner requires a vapor-liquid separation device for separating vapor refrigerant and liquid refrigerant from the refrigerant in a vapor-liquid mixed state generated by the outdoor heat exchanger of the outdoor unit.
- a first bypass pipe has one end connected to a liquid-phase outlet of the vapor-liquid separation device and a plurality of other split ends, each of which connects to a flow control device of the indoor unit.
- the flow control device of the indoor unit in the room to be cooled depressurizes the high-pressurized liquid refrigerant for changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure, which is supplied to the indoor heat exchanger.
- the vapor refrigerant output from the vapor-liquid separation device is supplied to the indoor unit of the room to be heated.
- the liquid refrigerant output from the vapor-liquid separation device is saturated liquid, unless it is overcooled, it may somehow be depressurized in a way up to the flow control device of the indoor unit so as to change its phase to the two-phase vapor-liquid phase, thereby causing noise and pressure pulsation in the flow control device.
- a second bypass pipe is arranged adjacent and connected to the first bypass pipe, and another flow control device for controlling the flow through the second bypass pipe, which depressurizes a portion of the liquid refrigerant output from the vapor-liquid separation device to generate the two-phase vapor-liquid refrigerant of low temperature and low pressure, thereby overcooling the liquid refrigerant output from the vapor-liquid separation device with the vapor-liquid refrigerant through the second bypass pipe.
- another flow control device intervenes in the first bypass pipe for controlling flow amount of the liquid refrigerant output from the vapor-liquid separation device for preventing the liquid refrigerant from being mixed in the vapor refrigerant.
- one of the aspects of the present invention is to provide a multi-split type air conditioner using the refrigerant of carbon dioxide, which substantially reduces the number of components of the relay device and improves controllability of the cooling and heating features of the indoor heat exchangers.
- an air conditioner of one of the aspects according to the present invention is to provide an air conditioner including an outdoor unit, a plurality of indoor units, and a relay device for connection between the outdoor unit and each of the indoor units.
- the outdoor unit includes an outdoor heat exchanger, a compressor for pressurizing a refrigerant of carbon dioxide or a composite having main ingredient of carbon dioxide, and a first switching member for switching a flow direction of the refrigerant through the outdoor heat exchanger, which are in fluid communication between first and second connection ends.
- Each of the indoor units includes an indoor heat exchanger and a first flow controller which are in fluid communication between first and second pipe connection ports.
- the relay device includes a plurality of second switching members, each of which the second switching members selectively connects the first pipe connection port of the respective indoor unit with the first or second connection end of the outdoor unit.
- the relay device also includes a first bypass pipe for connection between the second connection end of the outdoor unit and each of the second pipe connection ports of the indoor units, and a second flow controller intervening in the first bypass pipe.
- the refrigerant flows through the refrigerant delivery port of the compressor, the first switching member, the outdoor heat exchanger, and the second connection end into the indoor unit in the room to be heated, in which the refrigerant heats the air in the indoor heat exchanger.
- the refrigerant flows into the indoor units in the rooms to be cooled, in which after the refrigerant is depressurized when passing through the first flow controller for cooling the air in the indoor heat exchangers of the indoor units, following to the first connection end.
- the refrigerant of carbon dioxide or a composite having main ingredient of carbon dioxide remains in a supercritical state while flowing from the refrigerant delivery port of the compressor prior to the indoor heat exchangers of the indoor units.
- the noise and the pressure pulsation which might be generated at the first flow controller can be suppressed or avoided.
- the vapor-liquid separation device 40 and associated components can be eliminated, which substantially reduce the number of the components of the relay device. Also, the controllability of the indoor heat exchanger for heating and cooling the rooms can fairly be improved due to the fewer components.
- Fig. 1 illustrates the first embodiment of an air conditioner according to the present invention.
- the air conditioner 2 uses carbon dioxide as a refrigerant, and includes, in general, an outdoor unit 4, a plurality of indoor units 6, and a relay device 8 for connection between the outdoor unit 4 and the indoor units 6. While there are shown three of the indoor units 6 (i.e., 6P, 6Q, 6R) in the present embodiment, the present invention cannot be limited by the number of the indoor units 6, as long as the air conditioner has more than two of the indoor units.
- the air conditioner 2 performs in a cooling operation mode in which each of the rooms having the respective indoor unit is to be cooled, and in a heating operation mode in which each of the rooms is to be heated. Also, it performs in another two modes where one of the rooms is cooled while another one of the rooms is heated, simultaneously (i.e., principally-cooling and principally-heating operation modes).
- the indoor unit 4 includes a compressor 10 for compressing the refrigerant, a heat exchanger (outdoor heat exchanger) 12, and a first switching member 16 such as a four-way switching valve, all of which are in fluid communication between first and second connection end 20a, 20b.
- the compressor 10 has a refrigerant delivery port 10a and a refrigerant suction port 10b connected to the first switching member 16 via the pipes 14a, 14b, respectively.
- the first switching member 16 is also connected via the pipe 14d to the first connection end 20a which is in turn connected to a pipe 18a of the relay device 8.
- the heat exchanger 12 has one end 12a connected to the first switching member 16 via the pipe 14c and the other end connected via the pipe 14e to a second connection end 20b which is in turn connected to another pipe 18b of the relay device 8.
- the pipes 18a, 18b are referred to as inter-unit pipes for connection between the outdoor unit 4 and the indoor units 6P-6R.
- the switching member 16 is designed to switch a flow direction of the refrigerator through the heat exchanger 12 between first and second flow conditions in accordance with the operation modes.
- the first connection end 20a is connected to the refrigerant suction port 10b of the compressor 10 via the pipes 14d, 14b
- the refrigerant delivery port 10a of the compressor 10 is connected to one end 12a of the heat exchanger 12 via the pipes 14a, 14c, in which the refrigerant flows from one end 12a to the other end 12b of the heat exchanger 12, i.e., from the first connection end 20a to the second connection end 20b.
- the second flow condition as illustrated in Fig.
- one end 12a of the heat exchanger 12 is connected to the refrigerant suction port 10b of the compressor 10 via the pipes 14c, 14b, and the refrigerant delivery port 10a of the compressor 10 is connected to the first connection end 20a via the pipes 14a, 14d, in which the refrigerant flows from the other end 12b to one end 12a of the heat exchanger 12, i.e., from the second connection end 20b to the first connection end 20a.
- a relay device 8 includes a plurality of three-way switching valves (second switching member) 22, e.g., three of the switching valves 22P, 22Q, 22R in the present embodiment, each of which has three of connection ports 24a, 24b, 24c.
- One inter-unit pipe 18a is split and connected to the connection ports 24a of the switching valves 22P, 22Q, 22R, and the other inter-unit pipe 18b is also split and connected to the connection ports 24b of the switching valves 22P, 22Q, 22R.
- each of the connection ports 24c of the switching valves 22P, 22Q, 22R is connected to the first pipe connection port 26a of the respective indoor unit 6.
- Each of the indoor units 6 includes another heat exchanger (indoor heat exchanger) 28 and a flow control valve (first flow controller) 32, which are in fluid communication between first and second pipe connection ports 26a, 26b.
- the heat exchanger 28 has one end connected via a pipe to the first pipe connection port 26a, and the other end connected via a pipe 30 to the second pipe connection port 26b which is in turn connected to a bypass pipe of the relay member 8.
- the flow control valves 32 (32P, 32Q, 32R) intervene in the pipe 30 for controlling the flow of the refrigerant therethrough.
- the relay device includes the first bypass pipe 30 having one end connected to the inter-unit pipe 18b and the other end split and connected to each of the second pipe connection ports 26b (and the flow control valves 32). Also, a second flow control valve 36 intervenes in the bypass pipe 30 for controlling the flow of refrigerant through the bypass pipe 30.
- FIGs. 2-5 illustrating the flow of the refrigerant
- Figs. 6-9 of the p-h diagram showing the relationship between the pressure and the enthalpy of the refrigerant.
- the switching member 16 switches to the first flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with one end 12a of the heat exchanger 12 and by connecting the refrigerant suction port 10b with the first connection end 20a), the second flow control valve 36 is fully opened, and the first flow control valves 32P-32R is throttled. Also, the connection port 24b of the three-way switching valve 22 is closed while the connection ports 24a, 24c are opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant is pressurized adiabatically, i.e., without heat exchange with ambient air, which is described by a constant-enthalpy line [1]-[2] in the p-h diagram (pressure-enthalpy diagram) of Fig. 6.
- the refrigerant of high pressure and high temperature flows through the first switching member 16 and heats the ambient air in the heat exchanger 12 to lower the temperature of the refrigerant.
- the pressure thereof is kept almost constant but slightly declining due to pressure loss in the heat exchanger 12 as the refrigerant is cooled, which is represented by a almost flat line [2]-[3] in the p-h diagram.
- the refrigerant of carbon dioxide according to the present invention is kept in a supercritical state at high temperature and lowers the temperature without condensation.
- the refrigerant from the heat exchanger 12 flows through the second connection end 20b and the bypass pipe 34, while the flow control valve 36 is fully opened, into each of the indoor units 6P-6R, in which throttling the flow control valves 32P-32R changes (depressurizes) the refrigerant to the two-phase vapor-liquid refrigerant of low temperature and low pressure.
- the refrigerant is depressurized at the flow control valves 32P-32R under the constant enthalpy, which is represented by a vertical line [3]-[4] of the p-h diagram.
- the two-phase vapor-liquid refrigerant of low temperature and low pressure As the two-phase vapor-liquid refrigerant of low temperature and low pressure is changing to the vapor refrigerant of low temperature and low pressure, it refrigerates (absorbs heat from) the ambient air in the heat exchanger 28.
- the pressure of the refrigerant is kept almost constant but slightly declining due to pressure loss in the heat exchanger 28 as the refrigerant absorbs heat, which is represented by a almost flat line [4]-[1] in the p-h diagram.
- the vapor refrigerant of low temperature and low pressure from the heat exchanger 28 returns through the three-way switching valves 22, the first connection end 20a, and the first switching member 16, into the compressor 10.
- the switching member 16 switches to the second flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with the first connection end 20a and by connecting the refrigerant suction port 10b with one end 12a of the heat exchanger 12), the second flow control valve 36 is fully opened, and the first flow control valves 32P-32R is throttled. Also, the connection port 24b of the three-way switching valve 22 is closed while the connection ports 24a, 24c are opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the vapor refrigerant of low pressure and low temperature (point [1]) to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant of high pressure and high temperature (point [2]) flows through the first switching member 16, the first connection end 20a, and the three-way switching valves 22 into each one of the heat exchangers 28 of the indoor units 6P-6R.
- the refrigerant heats the ambient air in the heat exchangers 28 thereby to lower the temperature of the refrigerant (point [3]), and is depressurized by the flow control valve 32 to be changed as the two-phase vapor-liquid refrigerant of low temperature and low pressure (point [4]).
- the refrigerant from each of the indoor units 6P-6R flows through the bypass pipe 34 and the second connection end 20b to the other end 12b of the heat exchanger 12.
- the two-phase vapor-liquid refrigerant refrigerates (absorbs heat from) the ambient air in the heat exchanger 12 to be the vapor refrigerant of low temperature and low pressure (point [1]), which returns to the compressor 10 through the switching member 16.
- the switching member 16 switches to the first flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with one end 12a of the heat exchanger 12 and by connecting the refrigerant suction port 10b with the first connection end 20a). Also, the second flow control valve 36 is closed, and the first flow control valves 32P and 32Q are throttled, while the valve 32R is fully opened. Further, each of the three-way switching valves 22P and 22Q has the connection port 24b being closed and the connection ports 24a and 24c being opened. The three-way switching valve 22R has the connection port 24a being closed and the connection ports 24b and 24c being opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the vapor refrigerant of low pressure and low temperature (point [1]) to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant of high pressure and high temperature (point [2]) flows through the first switching member 16 to the heat exchanger 12, heating the ambient air in the heat exchanger 12 thereby to lower the temperature of the refrigerant (point [3]).
- the refrigerant of high pressure from the heat exchanger 12 flows through the second connection end 20b and the three-way switching valve 22R into the indoor unit 6R to heat the ambient air in the heat exchanger 28 to lower the temperature of the refrigerant (point [4]). Then, the refrigerant is depressurized by the flow control valve 32P and 32Q to be the two-phase vapor-liquid refrigerant of low temperature and low pressure (point [5]). The refrigerant refrigerates (absorbs heat from) the ambient air in the heat exchanger 28 of the indoor units 6P, 6Q, changing to the vapor refrigerant of low temperature and low pressure (point [1]).
- the refrigerant from the indoor units 6P, 6Q passes through the three-way switching valve 22P and 22Q, the first connection end 20a, and the switching member 16, and returns to the compressor 10.
- the refrigerant of carbon dioxide according to the present invention can be kept in a supercritical state while flowing from the refrigerant delivery port 10a of the compressor 10 through the first switching member 16, the indoor heat exchanger 12, the indoor unit 6R, and the flow control valves 32P and 32Q of the indoor units 6P and 6Q. Therefore, noise and pressure pulsation can be avoided or reduced, which might otherwise be generated at the flow control valves 32P and 32Q of the indoor units 6P and 6Q.
- the air conditioner 2' includes the vapor-liquid separation device intervening in the inter-unit pipe 18b within the relay device 8', and the bypass pipe 34 is connected to the liquid-phase port of the vapor-liquid separation device 40.
- the switching member 16 switches to the first flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with one end 12a of the heat exchanger 12 and by connecting the refrigerant suction port 10b with the first connection end 20a). Also, the second flow control valve 36 and the first flow control valves 32P, 32Q are throttled, while the valve 32R is fully opened. Further, each of the three-way switching valves 22P, 22Q has the connection port 24b being closed and the connection ports 24a, 24c being opened. The three-way switching valve 22R has the connection port 24a being closed and the connection ports 24b and 24c being opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the fluorocarbon-based vapor refrigerant of low pressure and low temperature (point [1]) to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant of high pressure and high temperature flows through the first switching member 16 to the heat exchanger 12, in which the refrigerant heats the ambient air in the heat exchanger 12 to partially condense thereby to be the two-phase vapor-liquid refrigerant of high pressure, since the pressure of the refrigerant coming into the heat exchanger 12 is lower than the critical pressure.
- the two-phase vapor-liquid refrigerant from the heat exchanger 12 enters the vapor-liquid separation device 40.
- the vapor refrigerant runs through the three-way valve 22R into the heat exchanger 28 of the indoor unit 6R, in which the vapor refrigerant heats the ambient air in the heat exchanger 28 to condense, thereby changing to the liquid refrigerant of high pressure that passes through the flow control valve 32R.
- another liquid refrigerant in the vapor-liquid separation device 40 flows through the flow control valve 36 and joins with the former liquid refrigerant from the indoor unit 6R, both of which liquid refrigerant come into the indoor units 6P, 6Q. Then, the refrigerant is depressurized by the flow control valve 32P, 32Q, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure.
- the refrigerant refrigerates (absorbs heat from) the ambient air in the heat exchanger 28, further changing to the vapor refrigerant of low temperature and low pressure.
- the refrigerant from the indoor units 6P, 6Q passes through the three-way switching valve 22P, 22Q and the switching member 16, and returns to the compressor 10.
- the flow control valve 36 controls the flow amount of the liquid refrigerant running from the vapor-liquid separation device 40 so that the vapor refrigerant running from the vapor-liquid separation device 40 into the indoor unit 6R contains no liquid refrigerant.
- the liquid refrigerant is depressurized when passing through the flow control valve 36 and the bypass pipe 34.
- the liquid refrigerant running from the vapor-liquid separation device 40 is the saturated refrigerant, it can be the two-phase vapor-liquid refrigerant by depressurization, which causes noise and pressure pulsation generated when the vapor-liquid refrigerant passes the flow control valves 33P, 33Q of the indoor units 6P, 6Q.
- the conventional air conditioner 2' requires a feature designed for overcooling the liquid refrigerant running from the vapor-liquid separation device 40.
- a second bypass pipe 42 is arranged adjacent the first bypass pipe 34, which has one end connected to a portion of the first bypass pipe 34 downstream of the flow control valve 36 and the other end connected to the inter-unit pipe 18a.
- another flow control valve 44 is provided intervening in the second bypass pipe 42. This allows the liquid refrigerant at the flow control valve 44 to expand (depressurize) by throttling the flow control valve 44 thereby to obtain the two-phase vapor-liquid refrigerant of low temperature and low pressure.
- the second bypass pipe 42 with the vapor-liquid refrigerant overcools the refrigerant through the first bypass pipe 34 in regions between the vapor-liquid separation device 40 and the flow control valve 36 and between the flow control valve 36 and the connection portion.
- a substantial number of components of the relay device 8' can be eliminated by using the refrigerant of carbon dioxide. Also, fewer number of flow control valves improves controllability of the cooling and heating capacity for the indoor heat exchangers 32P-32R.
- the flow control valve 36 may be adjusted so that a portion of the refrigerant passes through the first bypass pipe 34, bypassing the indoor unit 6R. This prevents increase of the refrigerant flow, which may cause the refrigerant noise and the corrosion of the pipe.
- the switching member 16 switches to the second flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with the first connection end 20a and by connecting the refrigerant suction port 10b with one end 12a of the heat exchanger 12). Also, the second flow control valve 36 is throttled, and the first flow control valves 32P, 32Q are fully opened, while the first flow control valve 32R is throttled. Further, each of the three-way switching valves 22P, 22Q has the connection port 24b being closed and the connection ports 24a, 24c being opened. The three-way switching valve 22R has the connection port 24a being closed and the connection ports 24b and 24c being opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the vapor refrigerant of low pressure and low temperature (point [1]) to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant of high pressure and high temperature (point [2]) flows through the first switching member 16 and the three-way switching valve 22P, 22Q to the heat exchangers 28 of the indoor units 6P, 6Q, heating the ambient air in the heat exchangers 28 thereby to lower the temperature of the refrigerant (point [3]).
- the refrigerant entering the indoor unit 6R expands (depressurizes) at the flow control valve 32R, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure (point [4]). Also, the refrigerant all or partially evaporates to refrigerate the ambient air in the heat exchanger 28 (point [5]) and enters the three-way switching valves 22R.
- the refrigerant passing out of the heat exchanger 28 (point [5]) is the two-phase vapor-liquid refrigerant having the dryness close to 1.0.
- the remaining portion of the refrigerant (point [3]) bypasses the indoor unit 6R through the bypass pipe 34 and expands (depressurizes) at the flow control valve 36, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure (point [6]).
- the refrigerant passing out of the flow control valve 36 (point [6]) has the pressure slightly less than that of the refrigerant passing out of the heat exchanger 28 (point [5]).
- the air conditioner according to the present embodiment controls the refrigerant flow passing through the indoor unit that performs the cooling operation with adjustment of the flow control valve 36, thereby improving the operation efficiency.
- Fig. 11 illustrates the second embodiment of an air conditioner according to the present invention.
- the outdoor unit 4A of the air conditioner 2A includes a flow-path selecting member 52 in addition to the structure of the air conditioner 2 of the first embodiment.
- the flow-path selecting member 52 is designed such that the refrigerant flows from the outdoor unit 4A into the relay device 8A always through the second connection end 20b, and from the relay device 8A to the outdoor unit 4A always through the first connection end 20a, regardless of the operation modes.
- the flow-path selecting member 52 includes a pair of check valves 54, 56, intervening in the pipes between the first switching member 16 and the first connection end 20a, and between the heat exchanger 12 and the second connection end 20b, respectively.
- the check valve 54 allows the refrigerant to flow only in a direction from the first connection end 20a to the switching member 16, and the check valve 56 allows the refrigerant to flow only in a direction from the heat exchanger 12 to the second connection end 20b.
- the flow-path selecting member 52 includes a bypass pipe 58 having one end connected to an intermediate point of the pipe 14d between the switching member 16 and check valve 54 and the other end connected to the second connection end 20b.
- a check valve 60 is provided intervening in the bypass pipe 58, which allows the refrigerant to flow only in a direction from the switching member 16 to the second connection end 20b.
- the flow-path selecting member 52 includes a bypass pipe 62 having one end connected to the first connection end 20a and the other end connected to an intermediate point of the pipe 14e between the heat exchanger 12 and the check valves 56.
- a check valve 60 is provided intervening in the bypass pipe 62, which allows the refrigerant to flow only in a direction from the first connection end 20a to the heat exchanger 12.
- the relay device 8A includes a second bypass pipe 66 connecting between the first bypass pipe 34 and the inter-unit pipe 18a, and a third flow control valve 68 intervening in the second bypass pipe 66 for controlling the refrigerant flow running therethrough.
- the switching member 16 switches to the first flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with one end 12a of the heat exchanger 12 and by connecting the refrigerant suction port 10b with the first connection end 20a), the second flow control valve 36 is fully opened, and the first flow control valves 32P-32R is throttled, while the third flow control valve 68 is closed. Also, the connection ports 24b of the three-way switching valves 22 are closed while the connection ports 24a, 24c are opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant of high pressure and high temperature flows through the first switching member 16 into the heat exchanger 12, heating the ambient air in the heat exchanger 12 thereby to lower the temperature of the refrigerant without condensation.
- the refrigerant of high pressure from the heat exchanger 12 flows through the check valve 56, the second connection end 20b, and the first bypass pipe 34 (the second flow control valve 36 is fully opened) to the indoor units 6P-6R, in which the refrigerant expands (depressurizes) at the flow control valves 32P-32R, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure.
- the refrigerant refrigerates (absorbs heat from) the ambient air in the heat exchanger 28, changing to the vapor refrigerant of low temperature and low pressure.
- the refrigerant from the heat exchangers 28 of the indoor units 6P-6R flows through the three-way switching valve 22P-22R and the first connection end 20a.
- the refrigerant at the first connection end 20a has pressure less than the refrigerant between the heat exchanger 12 and the check valve 64 so that it is automatically guided to pass through the check valve 54 and the first switching member 16 back to the compressor 10.
- the switching member 16 switches to the second flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with the first connection end 20a and by connecting the refrigerant suction port 10b with one end 12a of the heat exchanger 12), the second flow control valve 36 is fully opened, and the first flow control valves 32P-32R is throttled while the third flow control valve 68 is fully opened. Also, the connection port 24a of the three-way switching valve 22 is closed while the connection ports 24b, 24c are opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant of high pressure and high temperature flows through the first switching member 16, the check valve 60, the second connection end 20b, and the three-way switching valves 22 to each one of the heat exchangers 28 of the indoor units 6P-6R.
- the refrigerant heats the ambient air in the heat exchangers 28 to lower the temperature of the refrigerant, and is depressurized by the flow control valve 32, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure.
- the refrigerant from each of the indoor units 6P-6R flows through the first bypass pipe 34 and the third flow control valve 68 (the second bypass pipe 66) into the first connection end 20a.
- the refrigerant at the first connection end 20a has pressure less than the refrigerant between the switching member 16 and the check valve 54 so that it is automatically guided through the check valve 64 to the other end 12b of the heat exchanger 12.
- the two-phase vapor-liquid refrigerant refrigerates (absorbs heat from) the ambient air in the heat exchanger 12, changing to the vapor refrigerant of low temperature and low pressure, which runs through the switching member 16 back to the compressor 10.
- the switching member 16 switches to the first flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with one end 12a of the heat exchanger 12 and by connecting the refrigerant suction port 10b with the first connection end 20a). Also, the second and third flow control valves 36, 68 are closed, and the first flow control valves 32P, 32Q are throttled, while the first flow control valve 32R is fully opened. Further, each of the three-way switching valves 22P, 22Q has the connection port 24b being closed and the connection ports 24a and 24c being opened. The three-way switching valve 22R has the connection port 24a being closed and the connection ports 24b, 24c being opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant of high pressure and high temperature flows through the first switching member 16 into the heat exchanger 12, heating the ambient air in the heat exchanger 12 thereby to lower the temperature of the refrigerant.
- the refrigerant of high pressure from the heat exchanger 12 flows through the check valve 56, the second connection end 20b, and the three-way switching valve 22R into the indoor unit 6R, heating the ambient air in the heat exchanger 28 thereby to lower the temperature of the refrigerant.
- the refrigerant is depressurized by the flow control valve 32P, 32Q, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure.
- the refrigerant refrigerates (absorbs heat from) the ambient air in the heat exchanger 28 of the indoor units 6P, 6Q, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure.
- the refrigerant from the indoor units 6P, 6Q passes through the three-way switching valve 22P, 22Q into the first connection end 20a.
- the refrigerant at the first connection end 20a has pressure less than the refrigerant between the heat exchanger 12 and the check valve 64 so that it is automatically guided to pass through the check valve 54 and the switching member 16 back to the compressor 10.
- the flow control valve 36 may be adjusted so that a portion of the refrigerant passes through the first bypass pipe 34 bypassing the indoor unit 6R. This prevents increase of the refrigerant flow, which may cause the refrigerant noise and the corrosion of the pipe.
- the switching member 16 switches to the second flow condition (by connecting the refrigerant delivery port 10a of the compressor 10 with the first connection end 20a and by connecting the refrigerant suction port 10b with one end 12a of the heat exchanger 12). Also, the second flow control valve 36 is closed, and the first flow control valves 32P, 32Q are fully opened, while the first flow control valve 32R and the third flow control valve 68 are throttled. Further, each of the three-way switching valves 22P, 22Q has the connection port 24a being closed and the connection ports 24b, 24c being opened. The three-way switching valve 22R has the connection port 24b being closed and the connection ports 24a, 24c being opened. In this arrangement, the compressor 10 initiates to be driven.
- Pressurization by the compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from the refrigerant delivery port 10a.
- the refrigerant of high pressure and high temperature flows through the first switching member 16 and the three-way switching valve 22P, 22Q into the heat exchangers 28 of the indoor units 6P and 6Q, heating the ambient air in the heat exchangers 28 thereby to lower the temperature of the refrigerant.
- the refrigerant entering the indoor unit 6R expands (depressurizes) at the flow control valve 32R, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure. Also, the refrigerant all or partially evaporates to refrigerate the ambient air in the heat exchanger 28 and enters the three-way switching valves 22R.
- the remaining portion of the refrigerant bypassing the indoor unit 6R passes through the first and second bypass pipes 34, 66 and expands (depressurizes) at the flow control valve 68 to be two-phase vapor-liquid refrigerant of low temperature and low pressure.
- the refrigerant passing out of the flow control valve 68 joins with the refrigerant passing out of the three-way control valve 22R to be the two-phase vapor-liquid refrigerant, which flows into the first connection end 20a of the outdoor unit 4.
- the refrigerant at the first connection end 20a has pressure less than the refrigerant between the switching member 16 and the check valve 54 so that it is automatically guided to return through the check valve 64 to the other end 12a of the heat exchanger 12.
- the two-phase vapor-liquid refrigerant refrigerates the ambient air in the heat exchanger 12 to change itself to be vapor refrigerant of low temperature and low pressure in the heat exchanger 12, which returns through the switching member 16 to the compressor 10.
- the air conditioner of the present embodiment has another advantage in addition to those of the first embodiment. That is, a pair of the inter-unit pipes connecting between the outdoor unit 4A and the indoor unit 6P-6R can be designed such that the refrigerant of high pressure flows only through one of the pipes 18b, and the refrigerant of low pressure flows only through the other one of the pipes 18a. Therefore, the inter-unit pipe 18a may have the pipe wall thickness less than that of the inter-unit pipe 18b.
- the three-way switching valve is used in the second embodiment.
- a pair of two-way valves 22, 23 may be adapted as illustrated in Fig. 12.
- the two-way valve 22 has one end connected to the inter-unit pipe 18a and the second bypass pipe 66, and the other end connected to the indoor unit 28.
- the another two-way valve 23 has one end connected to the inter-unit pipe 18b and the other end connected to the indoor unit 28.
- the flow directions of the refrigerant running through the inter-unit pipes 18a, 18b (and the two-way valves 22, 23) can be kept the same regardless the operation modes.
- the switching member may have any other structures rather than the three-way control valves 22P-22R, for selectively connecting the indoor heat exchanger 28 with the pipe 18a or 18b.
- the flow-path selecting member 52 may have any other structures for allowing the refrigerant to flow from the outdoor unit 4A to the relay device 8A only through the connection end 20b and from the relay device 8A to the outdoor unit 4A only through the connection end 20a, in which the present invention is not limited to the structure shown in Fig. 11.
- the switching member 16 switches to the first flow condition by connecting the refrigerant delivery port 10a of the compressor 10 with one end 12a of the heat exchanger 12 and by connecting the refrigerant suction port 10b with the first connection end 20a
- the flow-path selecting member 52 guides the refrigerant from the end 12b of the heat exchanger 12 to the connection end 20b and blocks it to the connection end 12a.
- the switching member 16 switches to the second flow condition by connecting the refrigerant delivery port 10a of the compressor 10 with the first connection end 20a and by connecting the refrigerant suction port 10b with one end 12a of the heat exchanger 12
- the flow-path selecting member 52 guides the refrigerant from the compressor 10 to the connection end 20b and blocks it to the connection end 12a. Any types of the flow-path selecting members having such structures are included in the present invention.
- carbon dioxide itself is used as the refrigerant, however, any composites having main ingredient of carbon dioxide may be used as the refrigerant.
- unit in the indoor and outdoor units is not intended to describe that all components are physically provided within or on the same housing.
- the structure having the flow control valve of the indoor unit located at a position remote from the housing in which the indoor heat exchanger 28 is provided also falls within the scope of the present invention.
- a plurality of pairs of outdoor heat exchangers and the compressors may be provided within the outdoor unit so that the refrigerant from each pairs of outdoor heat exchangers and the compressors join to flow from one of the inter-unit pipes, and the refrigerant from the other end of the inter-unit pipes is split to each pair of outdoor heat exchangers and the compressors.
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Abstract
Description
- The present invention generally relates to an air conditioner applying a refrigeration cycle. In particular, the present invention relates to a multi-split type air conditioner including an outdoor unit and a plurality of indoor units, performing in operation modes where all of the rooms are cooled and heated, and in other operation modes where one of the rooms is cooled while another one of the rooms is heated, simultaneously.
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Patent Document 1 discloses a multi-split type air conditioner, which includes an outdoor unit having a compressor and an outdoor heat exchanger, a plurality of indoor units, each having an indoor heat exchanger, and a relay device for connection between the outdoor unit and the indoor units. The multi-split type air conditioner performs in the cooling and heating operation modes cooling and heating all of the rooms, respectively. Also, it performs in other operation modes cooling one of the rooms while heating another one of the rooms simultaneously, which are referred to as a principally-cooling operation mode where cooling operation capacity is greater than heating operation capacity, and as a principally-heating operation mode where heating operation capacity is greater than cooling operation capacity. - In the principally-cooling operation mode, the conventional air conditioner requires a vapor-liquid separation device for separating vapor refrigerant and liquid refrigerant from the refrigerant in a vapor-liquid mixed state generated by the outdoor heat exchanger of the outdoor unit. A first bypass pipe has one end connected to a liquid-phase outlet of the vapor-liquid separation device and a plurality of other split ends, each of which connects to a flow control device of the indoor unit. The flow control device of the indoor unit in the room to be cooled depressurizes the high-pressurized liquid refrigerant for changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure, which is supplied to the indoor heat exchanger. On the other hand, the vapor refrigerant output from the vapor-liquid separation device is supplied to the indoor unit of the room to be heated.
Patent Document 1:JP 9-042804 - Since the liquid refrigerant output from the vapor-liquid separation device is saturated liquid, unless it is overcooled, it may somehow be depressurized in a way up to the flow control device of the indoor unit so as to change its phase to the two-phase vapor-liquid phase, thereby causing noise and pressure pulsation in the flow control device. To suppress the problem, i.e., to overcool the saturated liquid refrigerant, a second bypass pipe is arranged adjacent and connected to the first bypass pipe, and another flow control device for controlling the flow through the second bypass pipe, which depressurizes a portion of the liquid refrigerant output from the vapor-liquid separation device to generate the two-phase vapor-liquid refrigerant of low temperature and low pressure, thereby overcooling the liquid refrigerant output from the vapor-liquid separation device with the vapor-liquid refrigerant through the second bypass pipe. Also, in the vapor-liquid separation device, another flow control device intervenes in the first bypass pipe for controlling flow amount of the liquid refrigerant output from the vapor-liquid separation device for preventing the liquid refrigerant from being mixed in the vapor refrigerant.
- As above, the relay device of the conventional air conditioner requires a lot of components. Also, due to too many components, it is difficult to control the cooling and heating capacity of the indoor heat exchangers. The above-described air conditioner uses a fluorocarbon-based refrigerant having high score of the global warming potential that is an index indicating the degree how the greenhouse effect gas brings the global warming, as a basis (=1) for carbon dioxide.
- Therefore, one of the aspects of the present invention is to provide a multi-split type air conditioner using the refrigerant of carbon dioxide, which substantially reduces the number of components of the relay device and improves controllability of the cooling and heating features of the indoor heat exchangers.
- In order to achieve the above-described objects, an air conditioner of one of the aspects according to the present invention is to provide an air conditioner including an outdoor unit, a plurality of indoor units, and a relay device for connection between the outdoor unit and each of the indoor units. The outdoor unit includes an outdoor heat exchanger, a compressor for pressurizing a refrigerant of carbon dioxide or a composite having main ingredient of carbon dioxide, and a first switching member for switching a flow direction of the refrigerant through the outdoor heat exchanger, which are in fluid communication between first and second connection ends. Each of the indoor units includes an indoor heat exchanger and a first flow controller which are in fluid communication between first and second pipe connection ports. The relay device includes a plurality of second switching members, each of which the second switching members selectively connects the first pipe connection port of the respective indoor unit with the first or second connection end of the outdoor unit. The relay device also includes a first bypass pipe for connection between the second connection end of the outdoor unit and each of the second pipe connection ports of the indoor units, and a second flow controller intervening in the first bypass pipe.
- In the principally cooling operation mode of the present invention, the refrigerant flows through the refrigerant delivery port of the compressor, the first switching member, the outdoor heat exchanger, and the second connection end into the indoor unit in the room to be heated, in which the refrigerant heats the air in the indoor heat exchanger. After that, the refrigerant flows into the indoor units in the rooms to be cooled, in which after the refrigerant is depressurized when passing through the first flow controller for cooling the air in the indoor heat exchangers of the indoor units, following to the first connection end. The refrigerant of carbon dioxide or a composite having main ingredient of carbon dioxide remains in a supercritical state while flowing from the refrigerant delivery port of the compressor prior to the indoor heat exchangers of the indoor units. Therefore, the noise and the pressure pulsation which might be generated at the first flow controller can be suppressed or avoided. Thus, according to the present invention, since the refrigerant is kept in the supercritical state, unlike the conventional air conditioner, the vapor-
liquid separation device 40 and associated components can be eliminated, which substantially reduce the number of the components of the relay device. Also, the controllability of the indoor heat exchanger for heating and cooling the rooms can fairly be improved due to the fewer components. -
- Fig. 1 is a flow circuit of a refrigerant adapted in an air conditioner of the first embodiment of the present invention.
- Fig. 2 is the flow circuit similar to Fig. 1, indicating the flow circulation of the refrigerant in a cooling operation mode.
- Fig. 3 is the flow circuit similar to Fig. 1, indicating the flow circulation of the refrigerant in a heating operation mode.
- Fig. 4 is the flow circuit similar to Fig. 1, indicating the flow circulation of the refrigerant in a principally-cooling operation mode.
- Fig. 5 is the flow circuit similar to Fig. 1, indicating the flow circulation of the refrigerant in a principally-heating operation mode.
- Fig. 6 is a p-h diagram (pressure-enthalpy diagram) showing transition of the refrigerant illustrated in Fig. 2.
- Fig. 7 is a p-h diagram showing transition of the refrigerant illustrated in Fig. 3.
- Fig. 8 is a p-h diagram showing transition of the refrigerant illustrated in Fig. 4.
- Fig. 9 is a p-h diagram showing transition of the refrigerant illustrated in Fig. 5.
- Fig. 10 is a flow circuit of a refrigerant adapted in another air conditioner, as an example for comparison with one of the present invention.
- Fig. 11 is a flow circuit of a refrigerant adapted in an air conditioner of the second embodiment of the present invention.
- Fig. 12 is the flow circuit similar to Fig. 11, illustrating modification of the second embodiment.
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- 2:
- air conditioner
- 4:
- outdoor unit
- 6P-6R:
- indoor unit
- 8:
- relay device
- 10:
- compressor
- 10a:
- refrigerant delivery port
- 10b:
- refrigerant suction port
- 12:
- heat exchanger of an outdoor unit
- 16:
- first switching member (four-way switching valve)
- 18a, 18b:
- first and second inter-unit pipe
- 20a, 20b:
- first and second connection end
- 26a, 26b:
- first and second pipe connection port
- 28:
- heat exchanger of an indoor unit
- 32P-32R:
- first flow controller (flow control valve)
- 34:
- first bypass pipe
- 36:
- second flow controller (flow control valve)
- 52:
- flow-path selector
- 66:
- second bypass pipe
- 68:
- third flow controller (flow control valve)
- Referring to the attached drawings, the details of embodiments according to the present invention will be described hereinafter.
- Fig. 1 illustrates the first embodiment of an air conditioner according to the present invention. The
air conditioner 2 uses carbon dioxide as a refrigerant, and includes, in general, anoutdoor unit 4, a plurality ofindoor units 6, and arelay device 8 for connection between theoutdoor unit 4 and theindoor units 6. While there are shown three of the indoor units 6 (i.e., 6P, 6Q, 6R) in the present embodiment, the present invention cannot be limited by the number of theindoor units 6, as long as the air conditioner has more than two of the indoor units. - The
air conditioner 2 performs in a cooling operation mode in which each of the rooms having the respective indoor unit is to be cooled, and in a heating operation mode in which each of the rooms is to be heated. Also, it performs in another two modes where one of the rooms is cooled while another one of the rooms is heated, simultaneously (i.e., principally-cooling and principally-heating operation modes). - The
indoor unit 4 includes acompressor 10 for compressing the refrigerant, a heat exchanger (outdoor heat exchanger) 12, and afirst switching member 16 such as a four-way switching valve, all of which are in fluid communication between first andsecond connection end compressor 10 has arefrigerant delivery port 10a and arefrigerant suction port 10b connected to the first switchingmember 16 via thepipes first switching member 16 is also connected via thepipe 14d to thefirst connection end 20a which is in turn connected to apipe 18a of therelay device 8. Further, theheat exchanger 12 has oneend 12a connected to the first switchingmember 16 via thepipe 14c and the other end connected via thepipe 14e to asecond connection end 20b which is in turn connected to anotherpipe 18b of therelay device 8. As above, thepipes outdoor unit 4 and theindoor units 6P-6R. - The switching
member 16 is designed to switch a flow direction of the refrigerator through theheat exchanger 12 between first and second flow conditions in accordance with the operation modes. In the first flow condition as illustrated in Fig. 2, thefirst connection end 20a is connected to therefrigerant suction port 10b of thecompressor 10 via thepipes refrigerant delivery port 10a of thecompressor 10 is connected to oneend 12a of theheat exchanger 12 via thepipes end 12a to theother end 12b of theheat exchanger 12, i.e., from thefirst connection end 20a to thesecond connection end 20b. In the second flow condition as illustrated in Fig. 3, oneend 12a of theheat exchanger 12 is connected to therefrigerant suction port 10b of thecompressor 10 via thepipes refrigerant delivery port 10a of thecompressor 10 is connected to thefirst connection end 20a via thepipes other end 12b to oneend 12a of theheat exchanger 12, i.e., from thesecond connection end 20b to thefirst connection end 20a. - A
relay device 8 includes a plurality of three-way switching valves (second switching member) 22, e.g., three of the switchingvalves connection ports inter-unit pipe 18a is split and connected to theconnection ports 24a of the switchingvalves inter-unit pipe 18b is also split and connected to theconnection ports 24b of the switchingvalves connection ports 24c of the switchingvalves pipe connection port 26a of the respectiveindoor unit 6. - Each of the
indoor units 6 includes another heat exchanger (indoor heat exchanger) 28 and a flow control valve (first flow controller) 32, which are in fluid communication between first and secondpipe connection ports heat exchanger 28 has one end connected via a pipe to the firstpipe connection port 26a, and the other end connected via apipe 30 to the secondpipe connection port 26b which is in turn connected to a bypass pipe of therelay member 8. Also, the flow control valves 32 (32P, 32Q, 32R) intervene in thepipe 30 for controlling the flow of the refrigerant therethrough. - As above, the relay device includes the
first bypass pipe 30 having one end connected to theinter-unit pipe 18b and the other end split and connected to each of the secondpipe connection ports 26b (and the flow control valves 32). Also, a secondflow control valve 36 intervenes in thebypass pipe 30 for controlling the flow of refrigerant through thebypass pipe 30. - Next, the operation of the
air conditioner 2 so structured will be described herein, with reference to Figs. 2-5 illustrating the flow of the refrigerant and Figs. 6-9 of the p-h diagram showing the relationship between the pressure and the enthalpy of the refrigerant. In Figs. 2-5, the thick lines indicate pipes through which the refrigerant is running and the bracket indexes [i] (i = 1, 2, ...) shows positions where the phases of the refrigerant are illustrated by plotting the points with the bracket indexes [i] on the diagrams in Figs. 6-9. - When all of the
indoor units 6P-6R perform the cooling operation, the switchingmember 16 switches to the first flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with oneend 12a of theheat exchanger 12 and by connecting therefrigerant suction port 10b with thefirst connection end 20a), the secondflow control valve 36 is fully opened, and the firstflow control valves 32P-32R is throttled. Also, theconnection port 24b of the three-way switching valve 22 is closed while theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant is pressurized adiabatically, i.e., without heat exchange with ambient air, which is described by a constant-enthalpy line [1]-[2] in the p-h diagram (pressure-enthalpy diagram) of Fig. 6. - The refrigerant of high pressure and high temperature flows through the first switching
member 16 and heats the ambient air in theheat exchanger 12 to lower the temperature of the refrigerant. The pressure thereof is kept almost constant but slightly declining due to pressure loss in theheat exchanger 12 as the refrigerant is cooled, which is represented by a almost flat line [2]-[3] in the p-h diagram. Unlike the fluorocarbon-based refrigerant, the refrigerant of carbon dioxide according to the present invention is kept in a supercritical state at high temperature and lowers the temperature without condensation. - The refrigerant from the
heat exchanger 12 flows through thesecond connection end 20b and thebypass pipe 34, while theflow control valve 36 is fully opened, into each of theindoor units 6P-6R, in which throttling theflow control valves 32P-32R changes (depressurizes) the refrigerant to the two-phase vapor-liquid refrigerant of low temperature and low pressure. The refrigerant is depressurized at theflow control valves 32P-32R under the constant enthalpy, which is represented by a vertical line [3]-[4] of the p-h diagram. - As the two-phase vapor-liquid refrigerant of low temperature and low pressure is changing to the vapor refrigerant of low temperature and low pressure, it refrigerates (absorbs heat from) the ambient air in the
heat exchanger 28. The pressure of the refrigerant is kept almost constant but slightly declining due to pressure loss in theheat exchanger 28 as the refrigerant absorbs heat, which is represented by a almost flat line [4]-[1] in the p-h diagram. - The vapor refrigerant of low temperature and low pressure from the
heat exchanger 28 returns through the three-way switching valves 22, thefirst connection end 20a, and the first switchingmember 16, into thecompressor 10. - It should be noted that while the pressure of the vapor refrigerant immediately after coming out of the
heat exchanger 28 becomes lower than that of the refrigerant just before coming in thecompressor 10 during transfer through the pipes, the vapor refrigerant is represented by the same point [1]. Similarly, while the high pressure of the refrigerant just before the flow control valve 32 is slightly less than that of the refrigerant right after theheat exchanger 12, the refrigerant is represented by the same point [3]. The slight pressure reduction of the refrigerant and the pressure loss in theheat exchangers - When all of the
indoor units 6P-6R perform the heating operation, the switchingmember 16 switches to the second flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with thefirst connection end 20a and by connecting therefrigerant suction port 10b with oneend 12a of the heat exchanger 12), the secondflow control valve 36 is fully opened, and the firstflow control valves 32P-32R is throttled. Also, theconnection port 24b of the three-way switching valve 22 is closed while theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the vapor refrigerant of low pressure and low temperature (point [1]) to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant of high pressure and high temperature (point [2]) flows through the first switchingmember 16, thefirst connection end 20a, and the three-way switching valves 22 into each one of theheat exchangers 28 of theindoor units 6P-6R. The refrigerant heats the ambient air in theheat exchangers 28 thereby to lower the temperature of the refrigerant (point [3]), and is depressurized by the flow control valve 32 to be changed as the two-phase vapor-liquid refrigerant of low temperature and low pressure (point [4]). Then, the refrigerant from each of theindoor units 6P-6R flows through thebypass pipe 34 and thesecond connection end 20b to theother end 12b of theheat exchanger 12. The two-phase vapor-liquid refrigerant refrigerates (absorbs heat from) the ambient air in theheat exchanger 12 to be the vapor refrigerant of low temperature and low pressure (point [1]), which returns to thecompressor 10 through the switchingmember 16. - When two of the
indoor units indoor unit 6R performs the heating operation, the switchingmember 16 switches to the first flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with oneend 12a of theheat exchanger 12 and by connecting therefrigerant suction port 10b with thefirst connection end 20a). Also, the secondflow control valve 36 is closed, and the firstflow control valves valve 32R is fully opened. Further, each of the three-way switching valves connection port 24b being closed and theconnection ports way switching valve 22R has theconnection port 24a being closed and theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the vapor refrigerant of low pressure and low temperature (point [1]) to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant of high pressure and high temperature (point [2]) flows through the first switchingmember 16 to theheat exchanger 12, heating the ambient air in theheat exchanger 12 thereby to lower the temperature of the refrigerant (point [3]). - The refrigerant of high pressure from the
heat exchanger 12 flows through thesecond connection end 20b and the three-way switching valve 22R into theindoor unit 6R to heat the ambient air in theheat exchanger 28 to lower the temperature of the refrigerant (point [4]). Then, the refrigerant is depressurized by theflow control valve heat exchanger 28 of theindoor units - The refrigerant from the
indoor units way switching valve first connection end 20a, and the switchingmember 16, and returns to thecompressor 10. - The refrigerant of carbon dioxide according to the present invention can be kept in a supercritical state while flowing from the
refrigerant delivery port 10a of thecompressor 10 through the first switchingmember 16, theindoor heat exchanger 12, theindoor unit 6R, and theflow control valves indoor units flow control valves indoor units - In the meanwhile, as a comparative example, a conventional air conditioner using the fluorocarbon-based refrigerant will be described herein and illustrated in Fig. 10. The air conditioner 2' includes the vapor-liquid separation device intervening in the
inter-unit pipe 18b within the relay device 8', and thebypass pipe 34 is connected to the liquid-phase port of the vapor-liquid separation device 40. - When the conventional air conditioner performs in the principally cooling operation mode, i.e., when two of the
indoor units indoor unit 6R performs the heating operation, the switchingmember 16 switches to the first flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with oneend 12a of theheat exchanger 12 and by connecting therefrigerant suction port 10b with thefirst connection end 20a). Also, the secondflow control valve 36 and the firstflow control valves valve 32R is fully opened. Further, each of the three-way switching valves connection port 24b being closed and theconnection ports way switching valve 22R has theconnection port 24a being closed and theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the fluorocarbon-based vapor refrigerant of low pressure and low temperature (point [1]) to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant of high pressure and high temperature flows through the first switchingmember 16 to theheat exchanger 12, in which the refrigerant heats the ambient air in theheat exchanger 12 to partially condense thereby to be the two-phase vapor-liquid refrigerant of high pressure, since the pressure of the refrigerant coming into theheat exchanger 12 is lower than the critical pressure. The two-phase vapor-liquid refrigerant from theheat exchanger 12 enters the vapor-liquid separation device 40. The vapor refrigerant runs through the three-way valve 22R into theheat exchanger 28 of theindoor unit 6R, in which the vapor refrigerant heats the ambient air in theheat exchanger 28 to condense, thereby changing to the liquid refrigerant of high pressure that passes through theflow control valve 32R. Meanwhile, another liquid refrigerant in the vapor-liquid separation device 40 flows through theflow control valve 36 and joins with the former liquid refrigerant from theindoor unit 6R, both of which liquid refrigerant come into theindoor units flow control valve heat exchanger 28, further changing to the vapor refrigerant of low temperature and low pressure. The refrigerant from theindoor units way switching valve member 16, and returns to thecompressor 10. - The
flow control valve 36 controls the flow amount of the liquid refrigerant running from the vapor-liquid separation device 40 so that the vapor refrigerant running from the vapor-liquid separation device 40 into theindoor unit 6R contains no liquid refrigerant. Thus, the liquid refrigerant is depressurized when passing through theflow control valve 36 and thebypass pipe 34. As the liquid refrigerant running from the vapor-liquid separation device 40 is the saturated refrigerant, it can be the two-phase vapor-liquid refrigerant by depressurization, which causes noise and pressure pulsation generated when the vapor-liquid refrigerant passes the flow control valves 33P, 33Q of theindoor units - To address the drawback, the conventional air conditioner 2' requires a feature designed for overcooling the liquid refrigerant running from the vapor-
liquid separation device 40. In particular, asecond bypass pipe 42 is arranged adjacent thefirst bypass pipe 34, which has one end connected to a portion of thefirst bypass pipe 34 downstream of theflow control valve 36 and the other end connected to theinter-unit pipe 18a. Also, anotherflow control valve 44 is provided intervening in thesecond bypass pipe 42. This allows the liquid refrigerant at theflow control valve 44 to expand (depressurize) by throttling theflow control valve 44 thereby to obtain the two-phase vapor-liquid refrigerant of low temperature and low pressure. Thesecond bypass pipe 42 with the vapor-liquid refrigerant overcools the refrigerant through thefirst bypass pipe 34 in regions between the vapor-liquid separation device 40 and theflow control valve 36 and between theflow control valve 36 and the connection portion. - As above, when the fluorocarbon-based refrigerant is used in the air conditioner, too many components have to be incorporated into the relay device 8'.
- On the contrary, according to the present embodiment of the invention, a substantial number of components of the relay device 8' can be eliminated by using the refrigerant of carbon dioxide. Also, fewer number of flow control valves improves controllability of the cooling and heating capacity for the
indoor heat exchangers 32P-32R. - It should be noted that while in the principally cooling operation mode of the present embodiment, the
flow control valve 36 is closed so that all of the refrigerant flows theindoor unit 6R heating the room, theflow control valve 36 may be adjusted so that a portion of the refrigerant passes through thefirst bypass pipe 34, bypassing theindoor unit 6R. This prevents increase of the refrigerant flow, which may cause the refrigerant noise and the corrosion of the pipe. - When two of the
indoor units indoor unit 6R performs the cooling operation, the switchingmember 16 switches to the second flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with thefirst connection end 20a and by connecting therefrigerant suction port 10b with oneend 12a of the heat exchanger 12). Also, the secondflow control valve 36 is throttled, and the firstflow control valves flow control valve 32R is throttled. Further, each of the three-way switching valves connection port 24b being closed and theconnection ports way switching valve 22R has theconnection port 24a being closed and theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the vapor refrigerant of low pressure and low temperature (point [1]) to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant of high pressure and high temperature (point [2]) flows through the first switchingmember 16 and the three-way switching valve heat exchangers 28 of theindoor units heat exchangers 28 thereby to lower the temperature of the refrigerant (point [3]). After flowing through theheat exchangers 28 and theflow control valves indoor units indoor unit 6R and the remaining portion thereof bypasses theindoor unit 6R through thebypass pipe 34. - The refrigerant entering the
indoor unit 6R expands (depressurizes) at theflow control valve 32R, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure (point [4]). Also, the refrigerant all or partially evaporates to refrigerate the ambient air in the heat exchanger 28 (point [5]) and enters the three-way switching valves 22R. Although not limited thereto, according to the present embodiment of Fig. 9, the refrigerant passing out of the heat exchanger 28 (point [5]) is the two-phase vapor-liquid refrigerant having the dryness close to 1.0. - On the other hand, the remaining portion of the refrigerant (point [3]) bypasses the
indoor unit 6R through thebypass pipe 34 and expands (depressurizes) at theflow control valve 36, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure (point [6]). Although not limited thereto, according to the present embodiment of Fig. 9, the refrigerant passing out of the flow control valve 36 (point [6]) has the pressure slightly less than that of the refrigerant passing out of the heat exchanger 28 (point [5]). - The refrigerant passing out of the
flow control valve 36 and the refrigerant passing out of the three-way control valve 22R join to be the two-phase vapor-liquid refrigerant (point [7]), which flows through thesecond connection end 20b of theoutdoor unit 4 to theheat exchanger 12. Also, the two-phase vapor-liquid refrigerant refrigerates the ambient air in theheat exchanger 12, changing to the vapor refrigerate (point [1]), which passes through the switchingmember 16 back to thecompressor 10. - As above, the air conditioner according to the present embodiment controls the refrigerant flow passing through the indoor unit that performs the cooling operation with adjustment of the
flow control valve 36, thereby improving the operation efficiency. - Fig. 11 illustrates the second embodiment of an air conditioner according to the present invention. The
outdoor unit 4A of theair conditioner 2A includes a flow-path selecting member 52 in addition to the structure of theair conditioner 2 of the first embodiment. The flow-path selecting member 52 is designed such that the refrigerant flows from theoutdoor unit 4A into therelay device 8A always through thesecond connection end 20b, and from therelay device 8A to theoutdoor unit 4A always through thefirst connection end 20a, regardless of the operation modes. - In particular, the flow-
path selecting member 52 includes a pair ofcheck valves member 16 and thefirst connection end 20a, and between theheat exchanger 12 and thesecond connection end 20b, respectively. Thecheck valve 54 allows the refrigerant to flow only in a direction from thefirst connection end 20a to the switchingmember 16, and thecheck valve 56 allows the refrigerant to flow only in a direction from theheat exchanger 12 to thesecond connection end 20b. - Also, the flow-
path selecting member 52 includes abypass pipe 58 having one end connected to an intermediate point of thepipe 14d between the switchingmember 16 andcheck valve 54 and the other end connected to thesecond connection end 20b. Acheck valve 60 is provided intervening in thebypass pipe 58, which allows the refrigerant to flow only in a direction from the switchingmember 16 to thesecond connection end 20b. Further, the flow-path selecting member 52 includes abypass pipe 62 having one end connected to thefirst connection end 20a and the other end connected to an intermediate point of thepipe 14e between theheat exchanger 12 and thecheck valves 56. Acheck valve 60 is provided intervening in thebypass pipe 62, which allows the refrigerant to flow only in a direction from thefirst connection end 20a to theheat exchanger 12. - The
relay device 8A includes asecond bypass pipe 66 connecting between thefirst bypass pipe 34 and theinter-unit pipe 18a, and a thirdflow control valve 68 intervening in thesecond bypass pipe 66 for controlling the refrigerant flow running therethrough. - Next, each of the operation modes performed by the
air conditioner 2A' so structured will be described herein. - When all of the
indoor units 6P-6R perform the cooling operation, the switchingmember 16 switches to the first flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with oneend 12a of theheat exchanger 12 and by connecting therefrigerant suction port 10b with thefirst connection end 20a), the secondflow control valve 36 is fully opened, and the firstflow control valves 32P-32R is throttled, while the thirdflow control valve 68 is closed. Also, theconnection ports 24b of the three-way switching valves 22 are closed while theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant of high pressure and high temperature flows through the first switchingmember 16 into theheat exchanger 12, heating the ambient air in theheat exchanger 12 thereby to lower the temperature of the refrigerant without condensation. The refrigerant of high pressure from theheat exchanger 12 flows through thecheck valve 56, thesecond connection end 20b, and the first bypass pipe 34 (the secondflow control valve 36 is fully opened) to theindoor units 6P-6R, in which the refrigerant expands (depressurizes) at theflow control valves 32P-32R, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure. The refrigerant refrigerates (absorbs heat from) the ambient air in theheat exchanger 28, changing to the vapor refrigerant of low temperature and low pressure. The refrigerant from theheat exchangers 28 of theindoor units 6P-6R flows through the three-way switching valve 22P-22R and thefirst connection end 20a. The refrigerant at thefirst connection end 20a has pressure less than the refrigerant between theheat exchanger 12 and thecheck valve 64 so that it is automatically guided to pass through thecheck valve 54 and the first switchingmember 16 back to thecompressor 10. - When all of the
indoor units 6P-6R perform the heating operation, the switchingmember 16 switches to the second flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with thefirst connection end 20a and by connecting therefrigerant suction port 10b with oneend 12a of the heat exchanger 12), the secondflow control valve 36 is fully opened, and the firstflow control valves 32P-32R is throttled while the thirdflow control valve 68 is fully opened. Also, theconnection port 24a of the three-way switching valve 22 is closed while theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant of high pressure and high temperature flows through the first switchingmember 16, thecheck valve 60, thesecond connection end 20b, and the three-way switching valves 22 to each one of theheat exchangers 28 of theindoor units 6P-6R. The refrigerant heats the ambient air in theheat exchangers 28 to lower the temperature of the refrigerant, and is depressurized by the flow control valve 32, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure. Then, the refrigerant from each of theindoor units 6P-6R flows through thefirst bypass pipe 34 and the third flow control valve 68 (the second bypass pipe 66) into thefirst connection end 20a. The refrigerant at thefirst connection end 20a has pressure less than the refrigerant between the switchingmember 16 and thecheck valve 54 so that it is automatically guided through thecheck valve 64 to theother end 12b of theheat exchanger 12. The two-phase vapor-liquid refrigerant refrigerates (absorbs heat from) the ambient air in theheat exchanger 12, changing to the vapor refrigerant of low temperature and low pressure, which runs through the switchingmember 16 back to thecompressor 10. - When two of the
indoor units indoor unit 6R performs the heating operation, the switchingmember 16 switches to the first flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with oneend 12a of theheat exchanger 12 and by connecting therefrigerant suction port 10b with thefirst connection end 20a). Also, the second and thirdflow control valves flow control valves flow control valve 32R is fully opened. Further, each of the three-way switching valves connection port 24b being closed and theconnection ports way switching valve 22R has theconnection port 24a being closed and theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant of high pressure and high temperature flows through the first switchingmember 16 into theheat exchanger 12, heating the ambient air in theheat exchanger 12 thereby to lower the temperature of the refrigerant. The refrigerant of high pressure from theheat exchanger 12 flows through thecheck valve 56, thesecond connection end 20b, and the three-way switching valve 22R into theindoor unit 6R, heating the ambient air in theheat exchanger 28 thereby to lower the temperature of the refrigerant. Then, the refrigerant is depressurized by theflow control valve heat exchanger 28 of theindoor units indoor units way switching valve first connection end 20a. The refrigerant at thefirst connection end 20a has pressure less than the refrigerant between theheat exchanger 12 and thecheck valve 64 so that it is automatically guided to pass through thecheck valve 54 and the switchingmember 16 back to thecompressor 10. - It should be noted that while in the principally cooling operation mode of the second embodiment, the
flow control valve 36 is closed so that all of the refrigerant flows into theindoor unit 6R heating the room, theflow control valve 36 may be adjusted so that a portion of the refrigerant passes through thefirst bypass pipe 34 bypassing theindoor unit 6R. This prevents increase of the refrigerant flow, which may cause the refrigerant noise and the corrosion of the pipe. - When two of the
indoor units indoor unit 6R performs the cooling operation, the switchingmember 16 switches to the second flow condition (by connecting therefrigerant delivery port 10a of thecompressor 10 with thefirst connection end 20a and by connecting therefrigerant suction port 10b with oneend 12a of the heat exchanger 12). Also, the secondflow control valve 36 is closed, and the firstflow control valves flow control valve 32R and the thirdflow control valve 68 are throttled. Further, each of the three-way switching valves connection port 24a being closed and theconnection ports way switching valve 22R has theconnection port 24b being closed and theconnection ports compressor 10 initiates to be driven. - Pressurization by the
compressor 10 changes the vapor refrigerant of low pressure and low temperature to one of high pressure and high temperature, which is delivered from therefrigerant delivery port 10a. The refrigerant of high pressure and high temperature flows through the first switchingmember 16 and the three-way switching valve heat exchangers 28 of theindoor units heat exchangers 28 thereby to lower the temperature of the refrigerant. After flowing through theheat exchangers 28 and theflow control valves indoor units indoor unit 6R and the remaining portion thereof passes through thebypass pipe 34. - The refrigerant entering the
indoor unit 6R expands (depressurizes) at theflow control valve 32R, changing to the two-phase vapor-liquid refrigerant of low temperature and low pressure. Also, the refrigerant all or partially evaporates to refrigerate the ambient air in theheat exchanger 28 and enters the three-way switching valves 22R. - On the other hand, the remaining portion of the refrigerant bypassing the
indoor unit 6R passes through the first andsecond bypass pipes flow control valve 68 to be two-phase vapor-liquid refrigerant of low temperature and low pressure. The refrigerant passing out of theflow control valve 68 joins with the refrigerant passing out of the three-way control valve 22R to be the two-phase vapor-liquid refrigerant, which flows into thefirst connection end 20a of theoutdoor unit 4. The refrigerant at thefirst connection end 20a has pressure less than the refrigerant between the switchingmember 16 and thecheck valve 54 so that it is automatically guided to return through thecheck valve 64 to theother end 12a of theheat exchanger 12. The two-phase vapor-liquid refrigerant refrigerates the ambient air in theheat exchanger 12 to change itself to be vapor refrigerant of low temperature and low pressure in theheat exchanger 12, which returns through the switchingmember 16 to thecompressor 10. - The air conditioner of the present embodiment has another advantage in addition to those of the first embodiment. That is, a pair of the inter-unit pipes connecting between the
outdoor unit 4A and theindoor unit 6P-6R can be designed such that the refrigerant of high pressure flows only through one of thepipes 18b, and the refrigerant of low pressure flows only through the other one of thepipes 18a. Therefore, theinter-unit pipe 18a may have the pipe wall thickness less than that of theinter-unit pipe 18b. - The three-way switching valve is used in the second embodiment. Alternatively, a pair of two-way valves 22, 23 may be adapted as illustrated in Fig. 12. In particular, the two-way valve 22 has one end connected to the
inter-unit pipe 18a and thesecond bypass pipe 66, and the other end connected to theindoor unit 28. Also, the another two-way valve 23 has one end connected to theinter-unit pipe 18b and the other end connected to theindoor unit 28. To this end, similar to the second embodiment, the flow directions of the refrigerant running through theinter-unit pipes - Although not limited thereto, several embodiments have been explained above solely for purpose to describe the present invention, and the embodiments can be changed and modified without departing the scope of the present invention. For example, the switching member may have any other structures rather than the three-
way control valves 22P-22R, for selectively connecting theindoor heat exchanger 28 with thepipe - Also, in the second embodiment, the flow-
path selecting member 52 may have any other structures for allowing the refrigerant to flow from theoutdoor unit 4A to therelay device 8A only through theconnection end 20b and from therelay device 8A to theoutdoor unit 4A only through theconnection end 20a, in which the present invention is not limited to the structure shown in Fig. 11. Thus, when the switchingmember 16 switches to the first flow condition by connecting therefrigerant delivery port 10a of thecompressor 10 with oneend 12a of theheat exchanger 12 and by connecting therefrigerant suction port 10b with thefirst connection end 20a, the flow-path selecting member 52 guides the refrigerant from theend 12b of theheat exchanger 12 to theconnection end 20b and blocks it to theconnection end 12a. Also, when the switchingmember 16 switches to the second flow condition by connecting therefrigerant delivery port 10a of thecompressor 10 with thefirst connection end 20a and by connecting therefrigerant suction port 10b with oneend 12a of theheat exchanger 12, the flow-path selecting member 52 guides the refrigerant from thecompressor 10 to theconnection end 20b and blocks it to theconnection end 12a. Any types of the flow-path selecting members having such structures are included in the present invention. - In the above embodiments, carbon dioxide itself is used as the refrigerant, however, any composites having main ingredient of carbon dioxide may be used as the refrigerant.
- The term "unit" in the indoor and outdoor units is not intended to describe that all components are physically provided within or on the same housing. For instance, the structure having the flow control valve of the indoor unit located at a position remote from the housing in which the
indoor heat exchanger 28 is provided, also falls within the scope of the present invention. Also, a plurality of pairs of outdoor heat exchangers and the compressors may be provided within the outdoor unit so that the refrigerant from each pairs of outdoor heat exchangers and the compressors join to flow from one of the inter-unit pipes, and the refrigerant from the other end of the inter-unit pipes is split to each pair of outdoor heat exchangers and the compressors.
Claims (10)
- An air conditioner, comprising:an outdoor unit including an outdoor heat exchanger, a compressor for pressurizing a refrigerant of carbon dioxide or a composite having main ingredient of carbon dioxide, and a first switching member for switching a flow direction of the refrigerant through the outdoor heat exchanger, which are in fluid communication between first and second connection ends;a plurality of indoor units, each of said indoor units including an indoor heat exchanger and a first flow controller which are in fluid communication between first and second pipe connection ports; anda relay device including a plurality of second switching members, each of the second switching members selectively connecting the first pipe connection port of the respective indoor unit with either one of the first and second connection ends of the outdoor unit, a first bypass pipe for connection between the second connection end of the outdoor unit and each of the second pipe connection ports of the indoor units, and a second flow controller intervening in the first bypass pipe.
- The air conditioner according to Claim 1,
wherein the compressor has a refrigerant delivery port and a refrigerant suction port; and
wherein the first switching member switches in accordance with the operation modes of the air conditioner between first and second conditions, the first condition allowing connection of the refrigerant delivery port with one end of the outdoor heat exchanger and connection of the refrigerant suction port with the first connection end, the second condition allowing connection of the refrigerant delivery port with the first connection end and connection of the refrigerant suction port with said one end of the outdoor heat exchanger. - The air conditioner according to Claim 1,
wherein when the first switching member switches to the first and second conditions, the refrigerant heats air in the outdoor heat exchanger and the indoor heat exchanger, respectively, while remaining in a supercritical state without condensation. - The air conditioner according to Claim 1, further comprising:a flow-path selector for guiding the refrigerant from the outdoor heat exchanger to the second connection end and guiding the refrigerant from the first connection end to the refrigerant suction port when the first switching member switches to the first condition, and for guiding the refrigerant from the refrigerant delivery port to the second connection end and guiding the refrigerant from the first connection end to the outdoor heat exchanger when the first switching member switches to the second condition;a second bypass pipe for fluid communication between the first connection end of the outdoor unit and the first bypass pipe; anda third flow controller intervening in the second bypass pipe.
- The air conditioner according to Claim 4,
wherein the flow-path selector includes a first check valve intervening in a first path between the first connection end and the compressor, a second check valve intervening in a second path between the second connection end and the outdoor heat exchanger, a third check valve intervening in a third path between the first connection end and the outdoor heat exchanger, and a fourth check valve intervening in a fourth path between the second connection end and the compressor. - The air conditioner according to Claim 4,
wherein the second switching member connects to the first and second connection ends through first and second inter-unit pipes, respectively; and
wherein the first inter-unit pipe has a pipe wall thickness thinner than that of the second inter-unit pipe. - The air conditioner according to Claim 1,
wherein the first switching member and each of the second switching members are operable independently upon the other switching members. - The air conditioner according to Claim 1,
wherein the first switching member includes a four-way switching valve. - The air conditioner according to Claim 1,
wherein each of the second switching members includes a three-way switching valve connected to the first and second connection ends of the outdoor unit and the first pipe connection port of the respective indoor unit. - The air conditioner according to Claim 1,
wherein each of the second switching members includes a first two-way switching valve connected to the first connection end of the outdoor unit and the first pipe connection port of the respective indoor unit, and a second two-way switching valve connected to the second connection end of the outdoor unit and the first pipe connection port of the respective indoor unit.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2004340889 | 2004-11-25 | ||
PCT/JP2005/020109 WO2006057141A1 (en) | 2004-11-25 | 2005-11-01 | Air conditioner |
Publications (3)
Publication Number | Publication Date |
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EP1816416A1 true EP1816416A1 (en) | 2007-08-08 |
EP1816416A4 EP1816416A4 (en) | 2011-08-03 |
EP1816416B1 EP1816416B1 (en) | 2019-06-19 |
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Application Number | Title | Priority Date | Filing Date |
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EP05805432.1A Active EP1816416B1 (en) | 2004-11-25 | 2005-11-01 | Air conditioner |
Country Status (5)
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US (1) | US20090145151A1 (en) |
EP (1) | EP1816416B1 (en) |
JP (1) | JP4752765B2 (en) |
CN (1) | CN101065623B (en) |
WO (1) | WO2006057141A1 (en) |
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JPWO2010050006A1 (en) * | 2008-10-29 | 2012-03-29 | 三菱電機株式会社 | Air conditioner |
JP5098987B2 (en) * | 2008-12-11 | 2012-12-12 | ダイキン工業株式会社 | Air conditioner |
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WO2011048695A1 (en) | 2009-10-23 | 2011-04-28 | 三菱電機株式会社 | Air conditioning device |
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JP5511838B2 (en) * | 2009-10-28 | 2014-06-04 | 三菱電機株式会社 | Air conditioner |
JP5323202B2 (en) * | 2009-10-29 | 2013-10-23 | 三菱電機株式会社 | Air conditioner |
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JP5436575B2 (en) * | 2009-11-30 | 2014-03-05 | 三菱電機株式会社 | Air conditioner |
US8844301B2 (en) * | 2010-02-10 | 2014-09-30 | Mitsubishi Electric Corporation | Air-conditioning apparatus |
CN103080668B (en) * | 2010-09-10 | 2015-05-06 | 三菱电机株式会社 | Air-conditioning device |
EP2642219B1 (en) * | 2010-11-19 | 2018-12-26 | Mitsubishi Electric Corporation | Air conditioner |
CN103328909B (en) * | 2011-01-31 | 2015-04-01 | 三菱电机株式会社 | Air-conditioning device |
US9933205B2 (en) * | 2011-05-23 | 2018-04-03 | Mitsubishi Electric Corporation | Air-conditioning apparatus |
JP5984914B2 (en) * | 2012-03-27 | 2016-09-06 | 三菱電機株式会社 | Air conditioner |
KR20150012498A (en) * | 2013-07-25 | 2015-02-04 | 삼성전자주식회사 | Heat pump and flow path switching apparatus |
CN104713264B (en) * | 2013-12-11 | 2017-05-03 | 重庆美的通用制冷设备有限公司 | Air source heat pump set |
CN105737333B (en) * | 2016-02-22 | 2018-09-07 | 广东美的暖通设备有限公司 | Multi-line system and its mode switch control method |
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KR20200114031A (en) * | 2019-03-27 | 2020-10-07 | 엘지전자 주식회사 | An air conditioning apparatus |
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Cited By (2)
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EP2924360A4 (en) * | 2012-12-28 | 2015-12-30 | Daikin Ind Ltd | Air conditioner and air conditioner construction method |
Also Published As
Publication number | Publication date |
---|---|
EP1816416A4 (en) | 2011-08-03 |
WO2006057141A1 (en) | 2006-06-01 |
CN101065623A (en) | 2007-10-31 |
CN101065623B (en) | 2013-05-22 |
JPWO2006057141A1 (en) | 2008-06-05 |
US20090145151A1 (en) | 2009-06-11 |
EP1816416B1 (en) | 2019-06-19 |
JP4752765B2 (en) | 2011-08-17 |
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