US20190301778A1 - Refrigeration cycle apparatus - Google Patents
Refrigeration cycle apparatus Download PDFInfo
- Publication number
- US20190301778A1 US20190301778A1 US16/342,323 US201616342323A US2019301778A1 US 20190301778 A1 US20190301778 A1 US 20190301778A1 US 201616342323 A US201616342323 A US 201616342323A US 2019301778 A1 US2019301778 A1 US 2019301778A1
- Authority
- US
- United States
- Prior art keywords
- oil
- compressor
- pipe
- refrigerant
- valve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000005057 refrigeration Methods 0.000 title claims abstract description 68
- 239000003507 refrigerant Substances 0.000 claims description 148
- 239000003921 oil Substances 0.000 description 253
- 239000007788 liquid Substances 0.000 description 57
- 238000010586 diagram Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 10
- 238000000926 separation method Methods 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000000034 method Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000001052 transient effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000010257 thawing Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B31/00—Compressor arrangements
- F25B31/002—Lubrication
- F25B31/004—Lubrication oil recirculating arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B31/00—Compressor arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/06—Several compression cycles arranged in parallel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/07—Details of compressors or related parts
- F25B2400/075—Details of compressors or related parts with parallel compressors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2500/00—Problems to be solved
- F25B2500/16—Lubrication
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/03—Oil level
Definitions
- the present invention relates to a refrigeration cycle apparatus, and more particularly to a refrigeration cycle apparatus including a compressor group in which a plurality of compressors are connected in parallel.
- a refrigeration cycle apparatus is provided with a refrigerant circuit in which refrigerant is circulated by a plurality of compressors.
- the amount of oil in one compressor and the amount of oil in another compressor may become unequal. For example, when the amount of oil is insufficient in one compressor, the compressor may suffer from galling.
- PTL 1 discloses such a refrigeration cycle apparatus.
- a refrigeration cycle apparatus when a refrigerator is in a transient operation, for example, when the refrigerator is started or restarted after defrosting, the refrigerant may not be sufficiently gasified, and thereby, the refrigerant containing liquid state refrigerant (liquid refrigerant) may be sucked into the compressor. This phenomenon is called a liquid back.
- the liquid refrigerant is fed into the one compressor together with oil, the actual amount of oil in the compressor is reduced, which lowers the concentration of the oil.
- the oil level of the one compressor is substantially the same as the oil level of the other compressors, despite that the one compressor has a lower oil concentration, and no oil will be supplied from the other compressors, the one compressor may suffer from galling.
- the present invention has been made to solve the above problem, and an object thereof is to provide a refrigeration cycle apparatus capable of preventing a compressor from suffering from galling even when a liquid back occurs.
- the refrigeration cycle apparatus is provided with a refrigerant circuit which is formed by connecting a compressor group in which a plurality of compressors including a first compressor and a second compressor are connected in parallel, a four-way valve, a condenser, an expansion valve, an evaporator, and an accumulator via a refrigerant pipe, and further includes an oil storage.
- the oil storage is connected to the discharge side of the compressor group via a first on-off valve, connected to the accumulator via a second on-off valve, and connected to the suction side of the compressor group via a third on-off valve.
- the refrigeration cycle apparatus of the present invention when a liquid back occurs, the oil stored in the oil storage is fed to the compressor group, which makes it possible to prevent the compressor group from suffering from galling.
- FIG. 1 is a diagram illustrating a structure including a refrigerant circuit of a refrigeration cycle apparatus including a compressor group according to an embodiment
- FIG. 2 is a diagram for explaining a position relationship of an accumulator, an oil storage, and a compressor group in the refrigeration cycle apparatus according to an embodiment
- FIG. 3 is a diagram for explaining the flow of refrigerant when the refrigeration cycle apparatus according to an embodiment is performing a cooling operation
- FIG. 4 is a diagram for explaining the flow of refrigerant when the refrigerating cycle apparatus according to an embodiment is performing a heating operation
- FIG. 5 is a flowchart illustrating the normal operation of the refrigeration cycle apparatus according to an embodiment
- FIG. 6 is a flowchart illustrating the operations of the refrigeration cycle apparatus according to an embodiment when a liquid back occurs
- FIG. 7 is a diagram illustrating a configuration of a refrigeration cycle apparatus according to a comparative example
- FIG. 8 is a first diagram for explaining the operations of the refrigeration cycle apparatus according to the comparative example.
- FIG. 9 is a second diagram for explaining the operations of the refrigeration cycle apparatus according to the comparative example.
- FIG. 10 is a first diagram for explaining the operations of the refrigeration cycle apparatus according to an embodiment when a liquid back occurs
- FIG. 11 is a second diagram for explaining the operations of the refrigeration cycle apparatus according to an embodiment when a liquid back occurs
- FIG. 12 is a first diagram for explaining an operation for fully filling an oil storage in the refrigeration cycle apparatus according to an embodiment with oil;
- FIG. 13 is a second diagram for explaining an operation for fully filling an oil storage in the refrigeration cycle apparatus according to an embodiment with oil;
- FIG. 14 is a first diagram for explaining an oil equalizing operation for equalizing the amount of oil in the compressor group of the refrigeration cycle apparatus according to an embodiment
- FIG. 15 is a second diagram for explaining an oil equalizing operation for equalizing the amount of oil in the compressor group of the refrigeration cycle apparatus according to an embodiment.
- FIG. 16 is a diagram illustrating a partial structure of a refrigeration cycle apparatus according to a modification of an embodiment.
- the refrigeration cycle apparatus 1 includes a compressor group 3 , a four-way valve 5 , a first heat exchanger 7 , an expansion valve 9 , a second heat exchanger 11 , and an accumulator 13 as the basic components.
- the second heat exchanger 11 is a water heat exchanger.
- the compressor group 3 , the four-way valve 5 , the first heat exchanger 7 , the expansion valve 9 , the second heat exchanger 11 , and the accumulator 13 are connected in this order via a refrigerant pipe 50 to form a refrigerant circuit.
- the compressor group 3 is connected to the four-way valve 5 via a refrigerant pipe 51 ( 50 ).
- the four-way valve 5 is connected to the first heat exchanger 7 via a refrigerant pipe 52 ( 50 ).
- the first heat exchanger 7 is connected to the expansion valve 9 via a refrigerant pipe 53 ( 50 ).
- the expansion valve 9 is connected to the second heat exchanger 11 via a refrigerant pipe 54 ( 50 ).
- the second heat exchanger 11 is connected to the four-way valve 5 via a refrigerant pipe 55 ( 50 ).
- the four-way valve 5 is connected to the accumulator 13 via a refrigerant pipe 56 ( 50 ).
- the accumulator 13 is connected to the compressor group 3 via a refrigerant pipe 57 ( 50 ).
- the compressor group 3 includes a first compressor 3 a and a second compressor 3 b .
- the first compressor 3 a and the second compressor 3 b are connected in parallel.
- the discharge side of the first compressor 3 a is connected to the refrigerant pipe 51 via a refrigerant pipe 51 a .
- the discharge side of the second compressor 3 b is connected to the refrigerant pipe 51 via a refrigerant pipe 51 b .
- the suction side of the first compressor 3 a is connected to the refrigerant pipe 57 via a refrigerant pipe 57 a .
- the suction side of the second compressor 3 b is connected to the refrigerant pipe 57 via a refrigerant pipe 57 b.
- the refrigeration cycle apparatus 1 further includes an oil storage 15 configured to supply oil stored therein to the compressor group 3 (the first compressor 3 a and the second compressor 3 b ).
- the oil storage 15 is connected to the discharge side of the compressor group 3 via a discharge gas bypass pipe (first pipe) 17 .
- One end of the discharge gas bypass pipe 17 is connected to the refrigerant pipe 51 as if it is branched from the refrigerant pipe 51 .
- the other end of the discharge gas bypass pipe 17 is connected to an upper end of the oil storage 15 .
- the discharge gas bypass pipe 17 is provided with a first solenoid valve (first on-off valve) 19 .
- the oil storage 15 is connected to the accumulator 13 via a first oil bypass pipe (second pipe) 21 .
- One end of the first oil bypass pipe 21 is connected to a side portion of the accumulator 13 close to the bottom face thereof.
- the other end of the first oil bypass pipe 21 is connected to the upper end of the oil storage 15 .
- the first oil bypass pipe 21 is provided with a second solenoid valve (second on-off valve) 23 .
- the oil storage 15 is connected to the compressor group 3 (the first compressor 3 a and the second compressor 3 b ) via a second oil bypass pipe (third pipe) 25 .
- the second oil bypass pipe 25 includes a main pipe 25 a , and a first branch pipe 25 b and a second branch pipe 25 c which are branched from the main pipe 25 a.
- the oil storage 15 is connected to the first compressor 3 a via the main pipe 25 a and the first branch pipe 25 b .
- the first branch pipe 25 b is connected to a lower end of the first compressor 3 a .
- the oil storage 15 is connected to the second compressor 3 b via the main pipe 25 a and the second branch pipe 25 c .
- the second branch pipe 25 c is connected to a lower end of the second compressor 3 b .
- the main pipe 25 a is provided with a third solenoid valve 27 .
- the accumulator 13 is connected to the compressor group 3 via a first oil pipe (fourth pipe) 31 a and a second oil pipe (fourth pipe) 31 b .
- One end of the first oil pipe 31 a and one end of the second oil pipe 31 b join together as one end of a common oil pipe 31 connected to a lower end of the accumulator 13 .
- the other end of the first oil pipe 31 a is connected to a lower end of the first compressor 3 a .
- the other end of the second oil pipe 31 b is connected to a lower end of the second compressor 3 b.
- the oil storage 15 is arranged relative to the compressor group 3 in such a manner that the bottom of the oil stored in the oil storage 15 , in other words, the bottom surface of a space for storing oil in the oil storage 15 is located at a position with a height H 1 from the bottom of the oil in the compressor group 3 , in other words, the bottom surface of a space for storing oil in the compressor group 3 , and the oil level of the oil maximally stored in the oil storage 15 is located at a position with a height H 3 from the bottom of the oil in the compressor group 3 .
- the accumulator 13 is arranged relative to the compressor group 3 in such a manner that the bottom of the oil stored in the accumulator 13 , in other words, the bottom surface of a space for storing oil in the accumulator 13 is located at a position with a height H 2 from the bottom of the oil in the compressor group 3 , and the height H 2 is higher than the oil level of the oil maximally stored in the oil storage 15 .
- the position relationship of the oil storage 15 , the accumulator 13 and the compressor group 3 is configured so as to facilitate an oil equalizing operation for equalizing oil in the compressor group 3 , an oil returning operation for returning oil to the compressor group 3 when a liquid back occurs, and an oil filling operation for fully filling the oil storage 15 with oil when a liquid back occurs.
- FIG. 3 the flow of the refrigerant circulated in the refrigerant circuit is indicated by the arrows.
- the high temperature and high pressure gas refrigerant discharged from the first compressor 3 a flows through the refrigerant pipe 51 a .
- the high temperature and high pressure gas refrigerant discharged from the second compressor 3 b flows through the refrigerant pipe 51 b .
- the refrigerant flowing through the refrigerant pipe 51 a and the refrigerant flowing through the refrigerant pipe 51 b join together and flow through the refrigerant pipe 51 .
- the refrigerant flowing through the refrigerant pipe 51 is fed to the first heat exchanger 7 which functions as a condenser via the four-way valve 5 and the refrigerant pipe 52 .
- the gas refrigerant is condensed and liquefied to a high pressure liquid refrigerant.
- the high pressure liquid refrigerant discharged from the first heat exchanger 7 flows through the refrigerant pipe 53 , and is converted by the expansion valve 9 into a two-phase refrigerant including a low pressure gas refrigerant and a liquid refrigerant.
- the two-phase refrigerant is fed to the second heat exchanger 11 which functions as an evaporator via the refrigerant pipe 54 .
- the second heat exchanger 11 is a water heat exchanger. In the second heat exchanger 11 , heat is exchanged between the refrigerant and water. Due to the heat exchange, the water is cooled, and the liquid refrigerant in the two-phase refrigerant is vaporized into a low pressure gas refrigerant. The low pressure gas refrigerant discharged from the second heat exchanger 11 is fed to the accumulator 13 via the refrigerant pipe 55 , the four-way valve 5 and the refrigerant pipe 56 . The oil contained in the refrigerant is separated in the accumulator 13 , and the separated oil is stored in the accumulator 13 .
- the refrigerant separated from the oil flows through the refrigerant pipe 57 and then flows through each of the refrigerant pipe 57 a and the refrigerant pipe 57 b which are branched from the refrigerant pipe 57 .
- the refrigerant flowing through the refrigerant pipe 57 a is fed to the first compressor 3 a where the refrigerant is compressed into a high temperature and high pressure gas refrigerant and discharged from the first compressor 3 a thereafter.
- the refrigerant flowing through the refrigerant pipe 57 b is fed to the second compressor 3 b where the refrigerant is compressed into a high temperature and high pressure gas refrigerant and discharged from the second compressor 3 b thereafter. This cycle is repeated subsequently.
- FIG. 4 the flow of the refrigerant is indicated by the arrows.
- the high temperature and high pressure gas refrigerant discharged from the first compressor 3 a flows through the refrigerant pipe 51 a
- the high temperature and high pressure gas refrigerant discharged from the second compressor 3 b flows through the refrigerant pipe 51 b , and then join together and flow through the refrigerant pipe 51 .
- the refrigerant flowing through the refrigerant pipe 51 is fed to the second heat exchanger 11 (water heat exchanger) which functions as a condenser via the four-way valve 5 and the refrigerant pipe 55 .
- the second heat exchanger 11 water heat exchanger
- the second heat exchanger 11 heat is exchanged between the refrigerant and water. Due to the heat exchange, the water is heated, and the high temperature and high pressure gas refrigerant is condensed and liquefied to a high pressure liquid refrigerant.
- the high pressure liquid refrigerant discharged from the second heat exchanger 11 flows through the refrigerant pipe 54 , and is converted by the expansion valve 9 into a two-phase refrigerant including a low pressure gas refrigerant and a liquid refrigerant.
- the two-phase refrigerant is fed to the first heat exchanger 7 which functions as an evaporator via the refrigerant pipe 53 .
- the liquid refrigerant in the two-phase refrigerant is vaporized into a low pressure gas refrigerant.
- the low pressure gas refrigerant discharged from the first heat exchanger 7 is fed to the accumulator 13 via the refrigerant pipe 52 , the four-way valve 5 and the refrigerant pipe 56 .
- the refrigerant separated from the oil in the accumulator 13 is fed to the first compressor 3 a via the refrigerant pipe 57 and the refrigerant pipe 57 a , and meanwhile is fed to the second compressor 3 b via the refrigerant pipe 57 and the refrigerant pipe 57 b .
- the refrigerant fed to each of the first compressor 3 a and the second compressor 3 b is compressed into a high temperature and high pressure gas refrigerant and discharged from each of the first compressor 3 a and the second compressor 3 b thereafter. This cycle is repeated subsequently.
- step S 1 the compressor group 3 is activated.
- step S 2 the first solenoid valve 19 , the second solenoid valve 23 and the third solenoid valve 27 are closed.
- step S 3 whether or not the oil storage 15 is full of oil is determined. If it is determined in step S 3 that the oil storage is full of oil, the second solenoid valve 23 and the third solenoid valve 27 are kept close in step S 4 .
- step S 3 if it is determined in step S 3 that the oil storage is not full of oil, the second solenoid valve 23 and the third solenoid valve 27 are opened so as to supply the oil stored in the accumulator 13 to the oil storage 15 until the oil storage 15 is full of oil in step S 7 . After the oil storage 15 is full of oil, the second solenoid valve 23 and the third solenoid valve 27 are closed in step S 4 .
- step S 5 whether or not a command to stop the compressor group 3 is issued is determined. If it is determined that a command to stop the compressor group 3 is issued in step S 5 , the compressor group 3 is stopped in step S 6 . On the other hand, if it is determined that a command to stop the compressor group 3 is not issued in step S 5 , the procedure returns to step S 3 , the operations of steps S 3 to S 5 are repeated.
- step LB 1 if the second solenoid valve 23 is closed, then it is kept close; and if the second solenoid valve 23 is open, then the second solenoid valve 23 is closed.
- step LB 3 whether or not the concentration of the oil in the compressor group is equal to or greater than a reference value (first value) is determined. If it is determined that the concentration of the oil in the compressor group 3 is equal to or greater than the reference value (first value) in step LB 3 , the first solenoid valve 19 and the third solenoid valve 27 are kept close in step LB 4 .
- the refrigerant containing the liquid refrigerant flows into the compressor group 3 , which will lower the concentration of the oil in the compressor group 3 . If it is determined that the concentration of the oil in the compressor group 3 is lower than the reference value, the first solenoid valve 19 and the third solenoid valve 27 are opened in step LB 6 .
- the second solenoid valve 23 is closed (step LB 2 ) if the first solenoid valve 19 and the third solenoid valve 27 are opened, the oil stored in the oil storage 15 is fed to the compressor group 3 via the second oil bypass pipe 25 by the discharge pressure of the compressor group 3 .
- the oil in the oil storage 15 is fed to the compressor group 3 until the concentration of the oil in the compressor group 3 becomes equal to or higher than the reference value.
- the first solenoid valve 19 and the third solenoid valve 27 are closed in step LB 4 .
- the series of operations in steps LB 1 to LB 5 are repeated subsequently.
- the refrigeration cycle apparatus 1 described above is provided with the oil storage 15 configured to store oil for the compressor group 3 , and when a liquid back occurs, the oil stored in the oil storage 15 is fed to the compressor group 3 so as to prevent the compressor group 3 from suffering from galling.
- the effect will be described in comparison with a refrigeration cycle apparatus according to a comparative example.
- a refrigeration cycle apparatus 101 includes a compressor group 103 including a first compressor 103 a and a second compressor 103 b , a four-way valve 105 , an outdoor heat exchanger 107 , an outdoor decompressor 109 a , an indoor decompressor 109 b , an indoor heat exchanger 111 , and an accumulator 113 .
- the compressor group 103 and the like are connected via a refrigerant pipe 150 to form a refrigerant circuit.
- the refrigeration cycle apparatus 101 further includes an oil equalizing device 151 configured to equalize the oil in the compressor group 103 .
- the oil equalizing device 151 includes a connection pipe 141 , a gas-liquid separation unit 143 , an oil pipe 145 , and an oil pipe 147 .
- the connection pipe 141 is connected between the compressor group 103 and the gas-liquid separation unit 143 .
- the oil pipe 145 is connected between the gas-liquid separation unit 143 and the refrigerant pipe 150 of the refrigerant circuit.
- the oil pipe 147 is connected between the gas-liquid separation unit 143 and the accumulator 113 .
- the refrigerant discharged from the compressor group 103 passes through the four-way valve 105 , the outdoor heat exchanger 107 , the outdoor decompressor 109 a , the indoor decompressor 109 b , the indoor heat exchanger 111 , the four-way valve 105 , and the accumulator 113 in order and flows back to the compressor group 103 .
- This cycle is repeated subsequently.
- the refrigerant discharged from the compressor group 103 passes through the four-way valve 105 , the indoor heat exchanger 111 , the indoor decompressor 109 b , the outdoor decompressor 109 a , the outdoor heat exchanger 107 , the four-way valve 105 , and the accumulator 113 in order and flows back to the compressor group 103 .
- This cycle is repeated subsequently.
- the oil 171 in the first compressor 103 a flows into the gas-liquid separation unit 143 via the connection pipe 141 , and thereby, the gas-liquid separation unit 143 is filled with the oil 171 .
- a part of the oil 171 in the gas-liquid separation unit 143 flows back to the first compressor 103 a via the oil pipe 147 , and the rest of the oil 171 in the gas-liquid separation unit 143 flows into the refrigerant pipe 150 via the oil pipe 145 .
- the oil 171 flowing into the refrigerant pipe 150 is fed to the compressor group 103 together with the refrigerant.
- the oil 171 in the first compressor 103 a with excessive oil may be gradually reduced, and similarly, the oil in a compressor (not shown) with less oil may be gradually increased.
- the oil equalizing operation for equalizing the amount of the oil 171 in the compressor group 103 is carried out in the refrigeration cycle apparatus 101 according to the comparative example.
- the low concentration oil 73 flowing into the gas-liquid separation unit 143 is fed to the compressor group 103 including the first compressor 103 a via the oil pipes 145 , 147 and the like. Since the oil 73 with a low concentration is fed to the first compressor 103 a , the oil 71 can not be sufficiently supplied to the first compressor 103 a , the whereby the first compressor 103 a may suffer from galling.
- the refrigeration cycle apparatus 1 when a liquid back occurs, the oil in the oil storage 15 is supplied to the compressor group 103 . The detail thereof will be described hereinafter.
- step S 1 to step S 6 the concentration of oil in the compressor group 3 is repeatedly detected (see FIG. 6 ).
- FIG. 10 when a liquid back occurs due to the transient operation or the like, the refrigerant containing the liquid refrigerant is fed to the accumulator 13 together with the oil. Therefore, the amount of the oil 73 with a low concentration increases in the accumulator 13 .
- the refrigerant containing the liquid refrigerant is fed to the compressor group 3 together with the oil 73 , the amount of the oil 73 with a low concentration increases in the compressor group 3 .
- the first solenoid valve 19 , the second solenoid valve 23 and the third solenoid valve 27 are all closed.
- step LB 3 When it is detected that the concentration of the oils 71 and 73 in the compressor group 3 is lower than the reference value (step LB 3 ), as illustrated in FIG. 11 , the first solenoid valve 19 and the third solenoid valve 27 are opened with the second solenoid valve 23 being kept close (step LB 6 ). As a result, the refrigerant discharged from the compressor group 3 flows through the discharge gas bypass pipe 17 which is branched from the refrigerant pipe 51 (and through the first solenoid valve 19 ).
- the oil 71 stored in the oil storage 15 is fed to the compressor group 3 .
- the oil 71 is fed to the first compressor 3 a via the main pipe 25 a (the third solenoid valve 27 ) and the first branch pipe 25 b of the second oil bypass pipe 25 .
- the oil 71 is fed to the second compressor 3 b via the main pipe 25 a and the second branch pipe 25 c.
- step LB 3 the concentration of the oils 71 and 73 in the compressor group 3 reaches the reference value (step LB 3 ).
- step LB 4 the first solenoid valve 19 and the third solenoid valve 27 are closed.
- the normal operation is performed while regularly detecting whether or not a liquid back occurs.
- the oil 71 preliminarily stored in the oil storage 15 is fed to the compressor group 3 when a liquid back occurs, which makes it possible to prevent the compressor group 3 from suffering from galling.
- a method for detecting the degree of superheat (overheat) on the discharge side or the suction side of the compressor group 3 may be given.
- the degree of superheat refers to the difference between the temperature of superheated vapor and the temperature of saturated dry vapor.
- a reference value for the degree of superheat may be set in advance, and if the degree of superheat becomes lower than the reference value, it is determined that the liquid back has occurred.
- a method for detecting the surface temperature of a compressor in the compressor group 3 may be given.
- the liquid refrigerant is fed to the compressor group 3 , which may cause the temperature of the compressor to decrease. Therefore, a reference value for the surface temperature may be set in advance, and if the surface temperature becomes lower than the reference value, it is determined that the liquid back has occurred.
- an oil sensor may be provided in the compressor group 3 to detect the concentration of oil directly. If the concentration of the detected oil is lower than a reference value set in advance for the oil concentration, it is determined that the liquid back has occurred.
- the oil 71 stored in the oil storage 15 is fed to the compressor group 3 . Thereby, the oil storage 15 is not full of the oil 71 .
- an operation for fully filling the oil storage 15 with the oil 71 will be explained.
- the oil 71 stored in the oil storage 15 is fed to the compressor group 3 , whereby the oil storage 15 is not full of the oil 71 .
- the first solenoid valve 19 , the second solenoid valve 23 and the third solenoid valve 27 will be closed (step LB 4 ).
- an operation of feeding the oil 71 stored in the accumulator 13 to the oil storage 15 is performed.
- the second solenoid valve 23 and the third solenoid valve 27 are opened with the first solenoid valve 19 being kept close.
- the oil 71 in the accumulator 13 is fed to the oil storage 15 via the first oil bypass pipe 21 (and the second solenoid valve 23 ).
- the second solenoid valve 23 and the third solenoid valve 27 are closed. In this way, the operation for fully filling the oil storage 15 with the oil 71 is completed in preparation for a liquid back.
- an oil level sensor may be disposed in the oil storage 15 .
- the oil level sensor By detecting the oil level of the oil fed from the accumulator 13 to the oil storage 15 with the oil level sensor, it is possible to determine that the oil storage is full of oil.
- the second solenoid valve 23 and the third solenoid valve 27 may be opened for a preset duration.
- the pressure loss from the accumulator 13 to the oil storage 15 may be estimated based on the position relationship between the accumulator 13 and the oil storage 15 and the structural configurations such as the length and the inner diameter of the first oil bypass pipe 21 and the like. Based on the pressure loss, the duration required to fully fill the oil storage 15 with oil may be calculated. By setting the duration in advance, it is possible to fully fill the oil storage 15 with oil.
- the compressor group 3 of the refrigeration cycle apparatus 1 includes a first compressor 3 a and a second compressor 3 b .
- An induction motor for each of the first compressor 3 a and the second compressor 3 b is driven at a desired frequency (rotational speed) according to the operation environment.
- the refrigerant discharged from the compressor group 3 flows through the refrigerant pipe 50 together with the oil.
- the frequency should be changed accordingly. For example, as illustrated in FIG. 14 , when the frequency suddenly drops, the amount of the oil 71 in the second compressor 3 b may become less than the amount of the oil 71 in the first compressor 3 a . In addition, even when there is no change in the frequency, due to the arrangement and connection of the refrigerant pipes 50 in the refrigerant circuit, the amount of the oil 71 in the first compressor 3 a and the amount of the oil 71 in the second compressor 3 b may become unequal.
- the equalizing operation is performed so as to make the amount of the oil 71 in the first compressor 3 a and the amount of the oil 71 in the second compressor 3 b substantially equal to each other based on the difference in the oil level of the oil 71 .
- the oil 71 in the accumulator 13 is fed to the second compressor 3 b via the oil pipe 31 and the second oil pipe 31 b (indicated by the arrows).
- the oil 71 in the first compressor 3 a is fed to the second compressor 3 b via the first oil pipe 31 a and the second oil pipe 31 b (indicated by the arrows).
- the amount of the oil 71 in the first compressor 3 a and the amount of the oil 71 in the second compressor 3 b are made substantially equal.
- the equalizing operation may be performed regularly during the operation of the refrigeration cycle apparatus 1 .
- the oil equalizing operation is performed so as to make the amount of the oil 71 in the first compressor 3 a and the amount of the oil 71 in the second compressor 3 b of the compressor group 3 equal to each other.
- the oil 71 stored in the oil storage 15 is fed to the first compressor 3 a or the second compressor 3 b containing the oil 73 with a low concentration, which makes it possible to prevent the first compressor 3 a or the second compressor 3 b from suffering from galling.
- the oil 71 is fed from the accumulator 13 to the oil storage 15 so as to fully fill the oil storage 15 with the oil 71 in preparation for another liquid back.
- a third solenoid valve 27 a is provided in the first branch pipe 25 b of the second oil bypass pipe 25
- a third solenoid valve 27 b is provided in the second branch pipe 25 c of the second oil bypass pipe 25 .
- the other configurations are the same as those of the refrigeration cycle apparatus 1 illustrated in FIG. 1 .
- the third solenoid valve 27 a is provided for the first compressor 3 a and the third solenoid valve 27 b is provided for the second compressor 3 b , the so that it is possible to selectively feed the oil 71 stored in the oil storage 15 to the first compressor 3 a and/or the second compressor 3 b containing the oil 71 , 73 with a low concentration.
- a compressor group in which two compressors, that is, a first compressor 3 a and a second compressor 3 b are connected in parallel is given as an example of the compressor group 3 .
- the number of compressors in the compressor group 3 is not limited to two, it may be three or more.
- refrigeration cycle apparatus described in the embodiment may be configured in various combination where necessary.
- the present invention is effectively used in a refrigeration cycle apparatus including a compressor group in which a plurality of compressors are connected in parallel.
Abstract
Description
- This application is a U.S. national stage application of International Application PCT/JP2016/088114, filed on Dec. 21, 2016, the contents of which are incorporated herein by reference.
- The present invention relates to a refrigeration cycle apparatus, and more particularly to a refrigeration cycle apparatus including a compressor group in which a plurality of compressors are connected in parallel.
- Conventionally, a refrigeration cycle apparatus is provided with a refrigerant circuit in which refrigerant is circulated by a plurality of compressors. In such a refrigeration cycle apparatus, when the refrigerant is being circulated in the refrigerant circuit, the amount of oil in one compressor and the amount of oil in another compressor may become unequal. For example, when the amount of oil is insufficient in one compressor, the compressor may suffer from galling.
- In order to prevent the problem from occurring, it is known to utilize the difference between the oil level of one compressor and the oil level of another compressor to supply the oil in one compressor with more oil to another compressor with less oil so as to equalize the amount of oil in each compressor.
PTL 1 discloses such a refrigeration cycle apparatus. - PTL 1: Japanese Patent Laying-Open No. 2007-139215 (Japanese Patent No. 4130676)
- In a refrigeration cycle apparatus, when a refrigerator is in a transient operation, for example, when the refrigerator is started or restarted after defrosting, the refrigerant may not be sufficiently gasified, and thereby, the refrigerant containing liquid state refrigerant (liquid refrigerant) may be sucked into the compressor. This phenomenon is called a liquid back.
- Suppose that a liquid back has occurred in one compressor. Thus, the liquid refrigerant is fed into the one compressor together with oil, the actual amount of oil in the compressor is reduced, which lowers the concentration of the oil. When the oil level of the one compressor is substantially the same as the oil level of the other compressors, despite that the one compressor has a lower oil concentration, and no oil will be supplied from the other compressors, the one compressor may suffer from galling.
- The present invention has been made to solve the above problem, and an object thereof is to provide a refrigeration cycle apparatus capable of preventing a compressor from suffering from galling even when a liquid back occurs.
- The refrigeration cycle apparatus according to the present invention is provided with a refrigerant circuit which is formed by connecting a compressor group in which a plurality of compressors including a first compressor and a second compressor are connected in parallel, a four-way valve, a condenser, an expansion valve, an evaporator, and an accumulator via a refrigerant pipe, and further includes an oil storage. The oil storage is connected to the discharge side of the compressor group via a first on-off valve, connected to the accumulator via a second on-off valve, and connected to the suction side of the compressor group via a third on-off valve.
- According to the refrigeration cycle apparatus of the present invention, when a liquid back occurs, the oil stored in the oil storage is fed to the compressor group, which makes it possible to prevent the compressor group from suffering from galling.
-
FIG. 1 is a diagram illustrating a structure including a refrigerant circuit of a refrigeration cycle apparatus including a compressor group according to an embodiment; -
FIG. 2 is a diagram for explaining a position relationship of an accumulator, an oil storage, and a compressor group in the refrigeration cycle apparatus according to an embodiment; -
FIG. 3 is a diagram for explaining the flow of refrigerant when the refrigeration cycle apparatus according to an embodiment is performing a cooling operation; -
FIG. 4 is a diagram for explaining the flow of refrigerant when the refrigerating cycle apparatus according to an embodiment is performing a heating operation; -
FIG. 5 is a flowchart illustrating the normal operation of the refrigeration cycle apparatus according to an embodiment; -
FIG. 6 is a flowchart illustrating the operations of the refrigeration cycle apparatus according to an embodiment when a liquid back occurs; -
FIG. 7 is a diagram illustrating a configuration of a refrigeration cycle apparatus according to a comparative example; -
FIG. 8 is a first diagram for explaining the operations of the refrigeration cycle apparatus according to the comparative example; -
FIG. 9 is a second diagram for explaining the operations of the refrigeration cycle apparatus according to the comparative example; -
FIG. 10 is a first diagram for explaining the operations of the refrigeration cycle apparatus according to an embodiment when a liquid back occurs; -
FIG. 11 is a second diagram for explaining the operations of the refrigeration cycle apparatus according to an embodiment when a liquid back occurs; -
FIG. 12 is a first diagram for explaining an operation for fully filling an oil storage in the refrigeration cycle apparatus according to an embodiment with oil; -
FIG. 13 is a second diagram for explaining an operation for fully filling an oil storage in the refrigeration cycle apparatus according to an embodiment with oil; -
FIG. 14 is a first diagram for explaining an oil equalizing operation for equalizing the amount of oil in the compressor group of the refrigeration cycle apparatus according to an embodiment; -
FIG. 15 is a second diagram for explaining an oil equalizing operation for equalizing the amount of oil in the compressor group of the refrigeration cycle apparatus according to an embodiment; and -
FIG. 16 is a diagram illustrating a partial structure of a refrigeration cycle apparatus according to a modification of an embodiment. - A refrigeration cycle apparatus according to an embodiment will be described. First, the basic components of the refrigeration cycle apparatus will be described. As illustrated in
FIG. 1 , therefrigeration cycle apparatus 1 includes acompressor group 3, a four-way valve 5, afirst heat exchanger 7, anexpansion valve 9, asecond heat exchanger 11, and anaccumulator 13 as the basic components. In therefrigeration cycle apparatus 1, thesecond heat exchanger 11 is a water heat exchanger. - The
compressor group 3, the four-way valve 5, thefirst heat exchanger 7, theexpansion valve 9, thesecond heat exchanger 11, and theaccumulator 13 are connected in this order via arefrigerant pipe 50 to form a refrigerant circuit. Thecompressor group 3 is connected to the four-way valve 5 via a refrigerant pipe 51 (50). The four-way valve 5 is connected to thefirst heat exchanger 7 via a refrigerant pipe 52 (50). Thefirst heat exchanger 7 is connected to theexpansion valve 9 via a refrigerant pipe 53 (50). - The
expansion valve 9 is connected to thesecond heat exchanger 11 via a refrigerant pipe 54 (50). Thesecond heat exchanger 11 is connected to the four-way valve 5 via a refrigerant pipe 55 (50). The four-way valve 5 is connected to theaccumulator 13 via a refrigerant pipe 56 (50). Theaccumulator 13 is connected to thecompressor group 3 via a refrigerant pipe 57 (50). - The
compressor group 3 includes afirst compressor 3 a and asecond compressor 3 b. Thefirst compressor 3 a and thesecond compressor 3 b are connected in parallel. The discharge side of thefirst compressor 3 a is connected to therefrigerant pipe 51 via arefrigerant pipe 51 a. The discharge side of thesecond compressor 3 b is connected to therefrigerant pipe 51 via arefrigerant pipe 51 b. The suction side of thefirst compressor 3 a is connected to the refrigerant pipe 57 via arefrigerant pipe 57 a. The suction side of thesecond compressor 3 b is connected to the refrigerant pipe 57 via arefrigerant pipe 57 b. - The
refrigeration cycle apparatus 1 according to the embodiment further includes anoil storage 15 configured to supply oil stored therein to the compressor group 3 (thefirst compressor 3 a and thesecond compressor 3 b). Theoil storage 15 is connected to the discharge side of thecompressor group 3 via a discharge gas bypass pipe (first pipe) 17. One end of the dischargegas bypass pipe 17 is connected to therefrigerant pipe 51 as if it is branched from therefrigerant pipe 51. The other end of the dischargegas bypass pipe 17 is connected to an upper end of theoil storage 15. The dischargegas bypass pipe 17 is provided with a first solenoid valve (first on-off valve) 19. - The
oil storage 15 is connected to theaccumulator 13 via a first oil bypass pipe (second pipe) 21. One end of the firstoil bypass pipe 21 is connected to a side portion of theaccumulator 13 close to the bottom face thereof. The other end of the firstoil bypass pipe 21 is connected to the upper end of theoil storage 15. The firstoil bypass pipe 21 is provided with a second solenoid valve (second on-off valve) 23. - The
oil storage 15 is connected to the compressor group 3 (thefirst compressor 3 a and thesecond compressor 3 b) via a second oil bypass pipe (third pipe) 25. The second oil bypass pipe 25 includes a main pipe 25 a, and a first branch pipe 25 b and a second branch pipe 25 c which are branched from the main pipe 25 a. - The
oil storage 15 is connected to thefirst compressor 3 a via the main pipe 25 a and the first branch pipe 25 b. The first branch pipe 25 b is connected to a lower end of thefirst compressor 3 a. Theoil storage 15 is connected to thesecond compressor 3 b via the main pipe 25 a and the second branch pipe 25 c. The second branch pipe 25 c is connected to a lower end of thesecond compressor 3 b. The main pipe 25 a is provided with athird solenoid valve 27. - Further, the
accumulator 13 is connected to thecompressor group 3 via a first oil pipe (fourth pipe) 31 a and a second oil pipe (fourth pipe) 31 b. One end of thefirst oil pipe 31 a and one end of thesecond oil pipe 31 b join together as one end of acommon oil pipe 31 connected to a lower end of theaccumulator 13. The other end of thefirst oil pipe 31 a is connected to a lower end of thefirst compressor 3 a. The other end of thesecond oil pipe 31 b is connected to a lower end of thesecond compressor 3 b. - Hereinafter, the position relationship between the
oil storage 15, theaccumulator 13 and thecompressor group 3 in the vertical direction (gravity direction) will be described. As illustrated inFIG. 2 , theoil storage 15 is arranged relative to thecompressor group 3 in such a manner that the bottom of the oil stored in theoil storage 15, in other words, the bottom surface of a space for storing oil in theoil storage 15 is located at a position with a height H1 from the bottom of the oil in thecompressor group 3, in other words, the bottom surface of a space for storing oil in thecompressor group 3, and the oil level of the oil maximally stored in theoil storage 15 is located at a position with a height H3 from the bottom of the oil in thecompressor group 3. Meanwhile, theaccumulator 13 is arranged relative to thecompressor group 3 in such a manner that the bottom of the oil stored in theaccumulator 13, in other words, the bottom surface of a space for storing oil in theaccumulator 13 is located at a position with a height H2 from the bottom of the oil in thecompressor group 3, and the height H2 is higher than the oil level of the oil maximally stored in theoil storage 15. - The position relationship of the
oil storage 15, theaccumulator 13 and thecompressor group 3 is configured so as to facilitate an oil equalizing operation for equalizing oil in thecompressor group 3, an oil returning operation for returning oil to thecompressor group 3 when a liquid back occurs, and an oil filling operation for fully filling theoil storage 15 with oil when a liquid back occurs. These operations will be described later. - Hereinafter, as the normal operation of the refrigeration cycle apparatus described above, a cooling operation thereof will be described with reference to
FIG. 3 . InFIG. 3 , the flow of the refrigerant circulated in the refrigerant circuit is indicated by the arrows. The high temperature and high pressure gas refrigerant discharged from thefirst compressor 3 a flows through therefrigerant pipe 51 a. The high temperature and high pressure gas refrigerant discharged from thesecond compressor 3 b flows through therefrigerant pipe 51 b. The refrigerant flowing through therefrigerant pipe 51 a and the refrigerant flowing through therefrigerant pipe 51 b join together and flow through therefrigerant pipe 51. The refrigerant flowing through therefrigerant pipe 51 is fed to thefirst heat exchanger 7 which functions as a condenser via the four-way valve 5 and the refrigerant pipe 52. - In the
first heat exchanger 7, heat is exchanged between the refrigerant and the outside air. Due to the heat exchange, the gas refrigerant is condensed and liquefied to a high pressure liquid refrigerant. The high pressure liquid refrigerant discharged from thefirst heat exchanger 7 flows through the refrigerant pipe 53, and is converted by theexpansion valve 9 into a two-phase refrigerant including a low pressure gas refrigerant and a liquid refrigerant. The two-phase refrigerant is fed to thesecond heat exchanger 11 which functions as an evaporator via the refrigerant pipe 54. - The
second heat exchanger 11 is a water heat exchanger. In thesecond heat exchanger 11, heat is exchanged between the refrigerant and water. Due to the heat exchange, the water is cooled, and the liquid refrigerant in the two-phase refrigerant is vaporized into a low pressure gas refrigerant. The low pressure gas refrigerant discharged from thesecond heat exchanger 11 is fed to theaccumulator 13 via the refrigerant pipe 55, the four-way valve 5 and the refrigerant pipe 56. The oil contained in the refrigerant is separated in theaccumulator 13, and the separated oil is stored in theaccumulator 13. - The refrigerant separated from the oil flows through the refrigerant pipe 57 and then flows through each of the
refrigerant pipe 57 a and therefrigerant pipe 57 b which are branched from the refrigerant pipe 57. The refrigerant flowing through therefrigerant pipe 57 a is fed to thefirst compressor 3 a where the refrigerant is compressed into a high temperature and high pressure gas refrigerant and discharged from thefirst compressor 3 a thereafter. The refrigerant flowing through therefrigerant pipe 57 b is fed to thesecond compressor 3 b where the refrigerant is compressed into a high temperature and high pressure gas refrigerant and discharged from thesecond compressor 3 b thereafter. This cycle is repeated subsequently. - Hereinafter, as the normal operation of the refrigeration cycle apparatus, a heating operation thereof will be described with reference to
FIG. 4 . InFIG. 4 , the flow of the refrigerant is indicated by the arrows. The high temperature and high pressure gas refrigerant discharged from thefirst compressor 3 a flows through therefrigerant pipe 51 a, and the high temperature and high pressure gas refrigerant discharged from thesecond compressor 3 b flows through therefrigerant pipe 51 b, and then join together and flow through therefrigerant pipe 51. The refrigerant flowing through therefrigerant pipe 51 is fed to the second heat exchanger 11 (water heat exchanger) which functions as a condenser via the four-way valve 5 and the refrigerant pipe 55. - In the
second heat exchanger 11, heat is exchanged between the refrigerant and water. Due to the heat exchange, the water is heated, and the high temperature and high pressure gas refrigerant is condensed and liquefied to a high pressure liquid refrigerant. The high pressure liquid refrigerant discharged from thesecond heat exchanger 11 flows through the refrigerant pipe 54, and is converted by theexpansion valve 9 into a two-phase refrigerant including a low pressure gas refrigerant and a liquid refrigerant. The two-phase refrigerant is fed to thefirst heat exchanger 7 which functions as an evaporator via the refrigerant pipe 53. - In the
first heat exchanger 7, heat is exchanged between the refrigerant and the outside air. Due to the heat exchange, the liquid refrigerant in the two-phase refrigerant is vaporized into a low pressure gas refrigerant. The low pressure gas refrigerant discharged from thefirst heat exchanger 7 is fed to theaccumulator 13 via the refrigerant pipe 52, the four-way valve 5 and the refrigerant pipe 56. - The refrigerant separated from the oil in the
accumulator 13 is fed to thefirst compressor 3 a via the refrigerant pipe 57 and therefrigerant pipe 57 a, and meanwhile is fed to thesecond compressor 3 b via the refrigerant pipe 57 and therefrigerant pipe 57 b. The refrigerant fed to each of thefirst compressor 3 a and thesecond compressor 3 b is compressed into a high temperature and high pressure gas refrigerant and discharged from each of thefirst compressor 3 a and thesecond compressor 3 b thereafter. This cycle is repeated subsequently. - In the
refrigeration cycle apparatus 1 according to the embodiment, while the above-described normal operation is being performed, whether or not theoil storage 15 is full of oil is determined regularly in preparation for a liquid back. A flowchart of such operation will be described with reference toFIG. 5 . - Firstly, in step S1, the
compressor group 3 is activated. In step S2, thefirst solenoid valve 19, thesecond solenoid valve 23 and thethird solenoid valve 27 are closed. In step S3, whether or not theoil storage 15 is full of oil is determined. If it is determined in step S3 that the oil storage is full of oil, thesecond solenoid valve 23 and thethird solenoid valve 27 are kept close in step S4. - On the other hand, if it is determined in step S3 that the oil storage is not full of oil, the
second solenoid valve 23 and thethird solenoid valve 27 are opened so as to supply the oil stored in theaccumulator 13 to theoil storage 15 until theoil storage 15 is full of oil in step S7. After theoil storage 15 is full of oil, thesecond solenoid valve 23 and thethird solenoid valve 27 are closed in step S4. - In step S5, whether or not a command to stop the
compressor group 3 is issued is determined. If it is determined that a command to stop thecompressor group 3 is issued in step S5, thecompressor group 3 is stopped in step S6. On the other hand, if it is determined that a command to stop thecompressor group 3 is not issued in step S5, the procedure returns to step S3, the operations of steps S3 to S5 are repeated. - In the
refrigeration cycle apparatus 1 according to the embodiment, while the series of operations are being performed, an operation of detecting the concentration of the oil in thecompressor group 3 is performed repeatedly. A flowchart of such operation will be described with reference toFIG. 6 . The operation starts from step LB1. In step LB2, if thesecond solenoid valve 23 is closed, then it is kept close; and if thesecond solenoid valve 23 is open, then thesecond solenoid valve 23 is closed. In step LB3, whether or not the concentration of the oil in the compressor group is equal to or greater than a reference value (first value) is determined. If it is determined that the concentration of the oil in thecompressor group 3 is equal to or greater than the reference value (first value) in step LB3, thefirst solenoid valve 19 and thethird solenoid valve 27 are kept close in step LB4. - On the other hand, when a liquid back occurs, the refrigerant containing the liquid refrigerant flows into the
compressor group 3, which will lower the concentration of the oil in thecompressor group 3. If it is determined that the concentration of the oil in thecompressor group 3 is lower than the reference value, thefirst solenoid valve 19 and thethird solenoid valve 27 are opened in step LB6. When thesecond solenoid valve 23 is closed (step LB2), if thefirst solenoid valve 19 and thethird solenoid valve 27 are opened, the oil stored in theoil storage 15 is fed to thecompressor group 3 via the second oil bypass pipe 25 by the discharge pressure of thecompressor group 3. - The oil in the
oil storage 15 is fed to thecompressor group 3 until the concentration of the oil in thecompressor group 3 becomes equal to or higher than the reference value. When the concentration of the oil in thecompressor group 3 becomes equal to or higher than the reference value, thefirst solenoid valve 19 and thethird solenoid valve 27 are closed in step LB4. The series of operations in steps LB1 to LB5 are repeated subsequently. - The
refrigeration cycle apparatus 1 described above is provided with theoil storage 15 configured to store oil for thecompressor group 3, and when a liquid back occurs, the oil stored in theoil storage 15 is fed to thecompressor group 3 so as to prevent thecompressor group 3 from suffering from galling. The effect will be described in comparison with a refrigeration cycle apparatus according to a comparative example. - As illustrated in
FIG. 7 , arefrigeration cycle apparatus 101 according to a comparative example includes a compressor group 103 including a first compressor 103 a and a second compressor 103 b, a four-way valve 105, anoutdoor heat exchanger 107, anoutdoor decompressor 109 a, anindoor decompressor 109 b, anindoor heat exchanger 111, and anaccumulator 113. The compressor group 103 and the like are connected via arefrigerant pipe 150 to form a refrigerant circuit. - The
refrigeration cycle apparatus 101 according to the comparative example further includes anoil equalizing device 151 configured to equalize the oil in the compressor group 103. Theoil equalizing device 151 includes aconnection pipe 141, a gas-liquid separation unit 143, anoil pipe 145, and anoil pipe 147. Theconnection pipe 141 is connected between the compressor group 103 and the gas-liquid separation unit 143. Theoil pipe 145 is connected between the gas-liquid separation unit 143 and therefrigerant pipe 150 of the refrigerant circuit. Theoil pipe 147 is connected between the gas-liquid separation unit 143 and theaccumulator 113. - The operation of the
refrigeration cycle apparatus 101 according to the comparative example will be briefly described hereinafter. During the cooling operation, the refrigerant discharged from the compressor group 103 passes through the four-way valve 105, theoutdoor heat exchanger 107, theoutdoor decompressor 109 a, theindoor decompressor 109 b, theindoor heat exchanger 111, the four-way valve 105, and theaccumulator 113 in order and flows back to the compressor group 103. This cycle is repeated subsequently. - During the heating operation, the refrigerant discharged from the compressor group 103 passes through the four-
way valve 105, theindoor heat exchanger 111, theindoor decompressor 109 b, theoutdoor decompressor 109 a, theoutdoor heat exchanger 107, the four-way valve 105, and theaccumulator 113 in order and flows back to the compressor group 103. This cycle is repeated subsequently. - As illustrated in
FIG. 8 , suppose that during the normal operation, the oil 171 in the first compressor 103 a of the compressor group 103 becomes excessive, and thus, the oil level of the oil 171 in the first compressor 103 a exceeds the position at which theconnection pipe 141 is connected to the first compressor 103 a. - In this case, the oil 171 in the first compressor 103 a flows into the gas-
liquid separation unit 143 via theconnection pipe 141, and thereby, the gas-liquid separation unit 143 is filled with the oil 171. A part of the oil 171 in the gas-liquid separation unit 143 flows back to the first compressor 103 a via theoil pipe 147, and the rest of the oil 171 in the gas-liquid separation unit 143 flows into therefrigerant pipe 150 via theoil pipe 145. Eventually, the oil 171 flowing into therefrigerant pipe 150 is fed to the compressor group 103 together with the refrigerant. - Due to the operation mentioned above, the oil 171 in the first compressor 103 a with excessive oil may be gradually reduced, and similarly, the oil in a compressor (not shown) with less oil may be gradually increased. As described above, the oil equalizing operation for equalizing the amount of the oil 171 in the compressor group 103 is carried out in the
refrigeration cycle apparatus 101 according to the comparative example. - Next, suppose that a liquid back occurs in the
refrigeration cycle apparatus 101 according to the comparative example. In this case, since the oil and the refrigerant including the liquid refrigerant are fed to the compressor, the amount of theoil 73 with a low concentration increases in the first compressor 103 a (seeFIG. 9 ). - As illustrated in
FIG. 9 , suppose that the oil level of theoils connection pipe 141 is connected to the compressor 103 a. In this case, despite that the concentration of theoil 73 is low, since the oil level is the same as the oil level when theoil 71 is excessive, theoil 73 with a low concentration flows into the gas-liquid separation unit 143. - The
low concentration oil 73 flowing into the gas-liquid separation unit 143 is fed to the compressor group 103 including the first compressor 103 a via theoil pipes oil 73 with a low concentration is fed to the first compressor 103 a, theoil 71 can not be sufficiently supplied to the first compressor 103 a, the whereby the first compressor 103 a may suffer from galling. - Compared with the
refrigeration cycle apparatus 101 according to the comparative example, in therefrigeration cycle apparatus 1 according to the embodiment, when a liquid back occurs, the oil in theoil storage 15 is supplied to the compressor group 103. The detail thereof will be described hereinafter. - First, as described above, while the series of operations are being performed in step S1 to step S6 (see
FIG. 5 ), the concentration of oil in thecompressor group 3 is repeatedly detected (seeFIG. 6 ). As illustrated inFIG. 10 , when a liquid back occurs due to the transient operation or the like, the refrigerant containing the liquid refrigerant is fed to theaccumulator 13 together with the oil. Therefore, the amount of theoil 73 with a low concentration increases in theaccumulator 13. - Since the refrigerant containing the liquid refrigerant is fed to the
compressor group 3 together with theoil 73, the amount of theoil 73 with a low concentration increases in thecompressor group 3. At the time when the liquid back occurs, thefirst solenoid valve 19, thesecond solenoid valve 23 and thethird solenoid valve 27 are all closed. - When it is detected that the concentration of the
oils compressor group 3 is lower than the reference value (step LB3), as illustrated inFIG. 11 , thefirst solenoid valve 19 and thethird solenoid valve 27 are opened with thesecond solenoid valve 23 being kept close (step LB6). As a result, the refrigerant discharged from thecompressor group 3 flows through the dischargegas bypass pipe 17 which is branched from the refrigerant pipe 51 (and through the first solenoid valve 19). - Due to the discharge pressure of the refrigerant acting on the
oil storage 15, theoil 71 stored in theoil storage 15 is fed to thecompressor group 3. Theoil 71 is fed to thefirst compressor 3 a via the main pipe 25 a (the third solenoid valve 27) and the first branch pipe 25 b of the second oil bypass pipe 25. Similarly, theoil 71 is fed to thesecond compressor 3 b via the main pipe 25 a and the second branch pipe 25 c. - This operation is repeated until the concentration of the
oils compressor group 3 reaches the reference value (step LB3). When it is detected that the concentration of theoil 71 in thecompressor group 3 is equal to (or greater than) the reference value (step LB3), thefirst solenoid valve 19 and thethird solenoid valve 27 are closed (step LB4). Thereafter, the normal operation (seeFIG. 5 ) is performed while regularly detecting whether or not a liquid back occurs. - Thus, in the
refrigeration cycle apparatus 1 according to the embodiment, theoil 71 preliminarily stored in theoil storage 15 is fed to thecompressor group 3 when a liquid back occurs, which makes it possible to prevent thecompressor group 3 from suffering from galling. - Hereinafter, examples of a method for detecting the concentration of the
oils compressor group 3 will be described. As an example, a method for detecting the degree of superheat (overheat) on the discharge side or the suction side of thecompressor group 3 may be given. The degree of superheat refers to the difference between the temperature of superheated vapor and the temperature of saturated dry vapor. When a liquid back occurs, the liquid refrigerant is fed to thecompressor group 3, and thus, the temperature of the refrigerant discharged from thecompressor group 3 will decrease, which consequently causes the degree of superheat to decrease. Therefore, a reference value for the degree of superheat may be set in advance, and if the degree of superheat becomes lower than the reference value, it is determined that the liquid back has occurred. - As another example, a method for detecting the surface temperature of a compressor in the
compressor group 3 may be given. When a liquid back occurs, the liquid refrigerant is fed to thecompressor group 3, which may cause the temperature of the compressor to decrease. Therefore, a reference value for the surface temperature may be set in advance, and if the surface temperature becomes lower than the reference value, it is determined that the liquid back has occurred. Furthermore, an oil sensor may be provided in thecompressor group 3 to detect the concentration of oil directly. If the concentration of the detected oil is lower than a reference value set in advance for the oil concentration, it is determined that the liquid back has occurred. - In the
refrigeration cycle apparatus 1 according to the embodiment, when a liquid back occurs, theoil 71 stored in theoil storage 15 is fed to thecompressor group 3. Thereby, theoil storage 15 is not full of theoil 71. In therefrigeration cycle apparatus 1, it is necessary to keep theoil storage 15 full of theoil 71 in preparation for a liquid back. Hereinafter, when theoil 71 in theoil storage 15 decreases, an operation for fully filling theoil storage 15 with theoil 71 will be explained. - First, as illustrated in
FIG. 12 , when a liquid back occurs, theoil 71 stored in theoil storage 15 is fed to thecompressor group 3, whereby theoil storage 15 is not full of theoil 71. Note that after the operation of feeding theoil 71 to thecompressor group 3 is completed, thefirst solenoid valve 19, thesecond solenoid valve 23 and thethird solenoid valve 27 will be closed (step LB4). - Next, as illustrated in
FIG. 13 , an operation of feeding theoil 71 stored in theaccumulator 13 to theoil storage 15 is performed. Thesecond solenoid valve 23 and thethird solenoid valve 27 are opened with thefirst solenoid valve 19 being kept close. As a result, theoil 71 in theaccumulator 13 is fed to theoil storage 15 via the first oil bypass pipe 21 (and the second solenoid valve 23). After theoil storage 15 is full of theoil 71, thesecond solenoid valve 23 and thethird solenoid valve 27 are closed. In this way, the operation for fully filling theoil storage 15 with theoil 71 is completed in preparation for a liquid back. - Hereinafter, examples of a method for detecting that the
oil storage 15 is full of theoil 71 will be described. First, as an example, an oil level sensor may be disposed in theoil storage 15. By detecting the oil level of the oil fed from theaccumulator 13 to theoil storage 15 with the oil level sensor, it is possible to determine that the oil storage is full of oil. - In addition, the
second solenoid valve 23 and thethird solenoid valve 27 may be opened for a preset duration. The pressure loss from theaccumulator 13 to theoil storage 15 may be estimated based on the position relationship between theaccumulator 13 and theoil storage 15 and the structural configurations such as the length and the inner diameter of the firstoil bypass pipe 21 and the like. Based on the pressure loss, the duration required to fully fill theoil storage 15 with oil may be calculated. By setting the duration in advance, it is possible to fully fill theoil storage 15 with oil. - Hereinafter, the equalizing operation performed during the normal operation in the
refrigeration cycle apparatus 1 according to the embodiment will be described. Thecompressor group 3 of therefrigeration cycle apparatus 1 includes afirst compressor 3 a and asecond compressor 3 b. An induction motor for each of thefirst compressor 3 a and thesecond compressor 3 b is driven at a desired frequency (rotational speed) according to the operation environment. The refrigerant discharged from thecompressor group 3 flows through therefrigerant pipe 50 together with the oil. - When the operation environment changes, the frequency should be changed accordingly. For example, as illustrated in
FIG. 14 , when the frequency suddenly drops, the amount of theoil 71 in thesecond compressor 3 b may become less than the amount of theoil 71 in thefirst compressor 3 a. In addition, even when there is no change in the frequency, due to the arrangement and connection of therefrigerant pipes 50 in the refrigerant circuit, the amount of theoil 71 in thefirst compressor 3 a and the amount of theoil 71 in thesecond compressor 3 b may become unequal. - When the amount of the
oil 71 becomes unequal, the equalizing operation is performed so as to make the amount of theoil 71 in thefirst compressor 3 a and the amount of theoil 71 in thesecond compressor 3 b substantially equal to each other based on the difference in the oil level of theoil 71. - First, due to the difference between the oil level P3 of the
oil 71 stored in theaccumulator 13 and the oil level P2 of theoil 71 in thesecond compressor 3 b, theoil 71 in theaccumulator 13 is fed to thesecond compressor 3 b via theoil pipe 31 and thesecond oil pipe 31 b (indicated by the arrows). Similarly, due to the difference between the oil level P1 of theoil 71 in thefirst compressor 3 a and the oil level P2 of theoil 71 in thesecond compressor 3 b, theoil 71 in thefirst compressor 3 a is fed to thesecond compressor 3 b via thefirst oil pipe 31 a and thesecond oil pipe 31 b (indicated by the arrows). - As illustrated in
FIG. 15 , according to the oil equalizing operation, the amount of theoil 71 in thefirst compressor 3 a and the amount of theoil 71 in thesecond compressor 3 b are made substantially equal. The equalizing operation may be performed regularly during the operation of therefrigeration cycle apparatus 1. - Thus, when the above-described
refrigeration cycle apparatus 1 is operating as a refrigeration cycle apparatus, the oil equalizing operation is performed so as to make the amount of theoil 71 in thefirst compressor 3 a and the amount of theoil 71 in thesecond compressor 3 b of thecompressor group 3 equal to each other. When a liquid back occurs, theoil 71 stored in theoil storage 15 is fed to thefirst compressor 3 a or thesecond compressor 3 b containing theoil 73 with a low concentration, which makes it possible to prevent thefirst compressor 3 a or thesecond compressor 3 b from suffering from galling. After the liquid back, theoil 71 is fed from theaccumulator 13 to theoil storage 15 so as to fully fill theoil storage 15 with theoil 71 in preparation for another liquid back. - As illustrated in
FIG. 16 , in the refrigeration cycle apparatus according to the modification, specifically, athird solenoid valve 27 a is provided in the first branch pipe 25 b of the second oil bypass pipe 25, and athird solenoid valve 27 b is provided in the second branch pipe 25 c of the second oil bypass pipe 25. The other configurations are the same as those of therefrigeration cycle apparatus 1 illustrated inFIG. 1 . - According to the refrigeration cycle apparatus of the modification, the
third solenoid valve 27 a is provided for thefirst compressor 3 a and thethird solenoid valve 27 b is provided for thesecond compressor 3 b, the so that it is possible to selectively feed theoil 71 stored in theoil storage 15 to thefirst compressor 3 a and/or thesecond compressor 3 b containing theoil - In the above-described
refrigeration cycle apparatus 1, a compressor group in which two compressors, that is, afirst compressor 3 a and asecond compressor 3 b are connected in parallel is given as an example of thecompressor group 3. However, the number of compressors in thecompressor group 3 is not limited to two, it may be three or more. - Further, the refrigeration cycle apparatus described in the embodiment may be configured in various combination where necessary.
- The embodiments disclosed herein are merely by way of example and not limited thereto. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the meaning and scope equivalent to the terms of the claims.
- The present invention is effectively used in a refrigeration cycle apparatus including a compressor group in which a plurality of compressors are connected in parallel.
Claims (10)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2016/088114 WO2018116407A1 (en) | 2016-12-21 | 2016-12-21 | Refrigeration cycle device |
Publications (1)
Publication Number | Publication Date |
---|---|
US20190301778A1 true US20190301778A1 (en) | 2019-10-03 |
Family
ID=62626203
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/342,323 Abandoned US20190301778A1 (en) | 2016-12-21 | 2016-12-21 | Refrigeration cycle apparatus |
Country Status (5)
Country | Link |
---|---|
US (1) | US20190301778A1 (en) |
EP (2) | EP3561410A4 (en) |
JP (1) | JP6745909B2 (en) |
CN (1) | CN110088540B (en) |
WO (1) | WO2018116407A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11460224B2 (en) * | 2018-10-31 | 2022-10-04 | Emerson Climate Technologies, Inc. | Oil control for climate-control system |
WO2024077250A1 (en) * | 2022-10-07 | 2024-04-11 | Johnson Controls Tyco IP Holdings LLP | Refrigeration system with reduced compressor thrust load |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2023073989A1 (en) * | 2021-11-01 | 2023-05-04 | 三菱電機株式会社 | Refrigeration cycle apparatus |
Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4586351A (en) * | 1984-05-18 | 1986-05-06 | Mitsubishi Denki Kabushiki Kaisha | Heat pump with multiple compressors |
US5369958A (en) * | 1992-10-15 | 1994-12-06 | Mitsubishi Denki Kabushiki Kaisha | Air conditioner |
US5729985A (en) * | 1994-12-28 | 1998-03-24 | Yamaha Hatsudoki Kabushiki Kaisha | Air conditioning apparatus and method for air conditioning |
US5996363A (en) * | 1996-10-28 | 1999-12-07 | Masushita Refrigeration Company | Oil level equalizing system for plural compressors |
US6604371B2 (en) * | 2000-01-21 | 2003-08-12 | Toshiba Carrier Corporation | Oil amount detector, refrigeration apparatus and air conditioner |
US20050279111A1 (en) * | 2004-06-10 | 2005-12-22 | Samsung Electronics Co., Ltd. | Air conditioner and method for performing oil equalizing operation in the air conditioner |
JP4845945B2 (en) * | 2008-09-19 | 2011-12-28 | 三菱電機株式会社 | Refrigeration equipment |
US20140154105A1 (en) * | 2012-12-03 | 2014-06-05 | Danfoss (Tianjin) Ltd. | Oil balancing apparatus and refrigeration device |
US8959947B2 (en) * | 2008-09-19 | 2015-02-24 | Johnson Controls Technology Company | Oil balance device, a compressor unit and a method for performing an oil balance operation between a plurality of compressor units |
US20150219372A1 (en) * | 2014-02-05 | 2015-08-06 | Lg Electronics Inc. | Heat-Pump System |
US20160003510A1 (en) * | 2013-02-21 | 2016-01-07 | Johnson Controls Technology Company | Lubrication and cooling system |
US9541313B2 (en) * | 2009-03-31 | 2017-01-10 | Mitsubishi Electric Corporation | Refrigerating device |
US9657977B2 (en) * | 2010-11-17 | 2017-05-23 | Hill Phoenix, Inc. | Cascade refrigeration system with modular ammonia chiller units |
US9726408B2 (en) * | 2013-12-26 | 2017-08-08 | Lg Electronics Inc. | Air conditioner |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05322331A (en) * | 1992-05-19 | 1993-12-07 | Mitsubishi Electric Corp | Air conditioner |
JPH11337194A (en) * | 1998-05-28 | 1999-12-10 | Mitsubishi Electric Corp | Chiller |
JP2001147047A (en) * | 1999-11-19 | 2001-05-29 | Fujitsu General Ltd | Air conditioner |
KR20060055154A (en) * | 2004-11-18 | 2006-05-23 | 엘지전자 주식회사 | A compressor oil retrieving apparatus of multi-type air conditioner |
JP4130676B2 (en) | 2005-11-15 | 2008-08-06 | 三星電子株式会社 | Compressor oil leveling device and refrigerator |
JP4929971B2 (en) * | 2006-10-18 | 2012-05-09 | ダイキン工業株式会社 | Oil separator |
CN101865553A (en) * | 2010-05-21 | 2010-10-20 | 北京中科华誉能源技术发展有限责任公司 | Flooded water source heat pump system with parallel scroll compressor |
JP2015038406A (en) * | 2013-08-19 | 2015-02-26 | ダイキン工業株式会社 | Refrigerating device |
CN203501555U (en) * | 2013-09-03 | 2014-03-26 | 深圳麦克维尔空调有限公司 | Compressor lubricating system and air-conditioning system |
JP6338698B2 (en) * | 2015-01-29 | 2018-06-06 | 三菱電機株式会社 | Refrigeration cycle equipment |
JP6187514B2 (en) * | 2015-03-20 | 2017-08-30 | ダイキン工業株式会社 | Refrigeration equipment |
CN105805986A (en) * | 2016-04-27 | 2016-07-27 | 田幼华 | Heat pump system with auxiliary oil return |
-
2016
- 2016-12-21 US US16/342,323 patent/US20190301778A1/en not_active Abandoned
- 2016-12-21 EP EP16924560.2A patent/EP3561410A4/en active Pending
- 2016-12-21 JP JP2018557454A patent/JP6745909B2/en active Active
- 2016-12-21 CN CN201680091524.3A patent/CN110088540B/en active Active
- 2016-12-21 WO PCT/JP2016/088114 patent/WO2018116407A1/en unknown
- 2016-12-21 EP EP21185466.6A patent/EP3913299A1/en active Pending
Patent Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4586351A (en) * | 1984-05-18 | 1986-05-06 | Mitsubishi Denki Kabushiki Kaisha | Heat pump with multiple compressors |
US5369958A (en) * | 1992-10-15 | 1994-12-06 | Mitsubishi Denki Kabushiki Kaisha | Air conditioner |
US5729985A (en) * | 1994-12-28 | 1998-03-24 | Yamaha Hatsudoki Kabushiki Kaisha | Air conditioning apparatus and method for air conditioning |
US5996363A (en) * | 1996-10-28 | 1999-12-07 | Masushita Refrigeration Company | Oil level equalizing system for plural compressors |
US6604371B2 (en) * | 2000-01-21 | 2003-08-12 | Toshiba Carrier Corporation | Oil amount detector, refrigeration apparatus and air conditioner |
US20050279111A1 (en) * | 2004-06-10 | 2005-12-22 | Samsung Electronics Co., Ltd. | Air conditioner and method for performing oil equalizing operation in the air conditioner |
JP4845945B2 (en) * | 2008-09-19 | 2011-12-28 | 三菱電機株式会社 | Refrigeration equipment |
US8959947B2 (en) * | 2008-09-19 | 2015-02-24 | Johnson Controls Technology Company | Oil balance device, a compressor unit and a method for performing an oil balance operation between a plurality of compressor units |
US9541313B2 (en) * | 2009-03-31 | 2017-01-10 | Mitsubishi Electric Corporation | Refrigerating device |
US9657977B2 (en) * | 2010-11-17 | 2017-05-23 | Hill Phoenix, Inc. | Cascade refrigeration system with modular ammonia chiller units |
US20140154105A1 (en) * | 2012-12-03 | 2014-06-05 | Danfoss (Tianjin) Ltd. | Oil balancing apparatus and refrigeration device |
US20160003510A1 (en) * | 2013-02-21 | 2016-01-07 | Johnson Controls Technology Company | Lubrication and cooling system |
US9726408B2 (en) * | 2013-12-26 | 2017-08-08 | Lg Electronics Inc. | Air conditioner |
US20150219372A1 (en) * | 2014-02-05 | 2015-08-06 | Lg Electronics Inc. | Heat-Pump System |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11460224B2 (en) * | 2018-10-31 | 2022-10-04 | Emerson Climate Technologies, Inc. | Oil control for climate-control system |
WO2024077250A1 (en) * | 2022-10-07 | 2024-04-11 | Johnson Controls Tyco IP Holdings LLP | Refrigeration system with reduced compressor thrust load |
Also Published As
Publication number | Publication date |
---|---|
JPWO2018116407A1 (en) | 2019-10-24 |
WO2018116407A1 (en) | 2018-06-28 |
EP3913299A1 (en) | 2021-11-24 |
CN110088540A (en) | 2019-08-02 |
EP3561410A4 (en) | 2020-02-12 |
CN110088540B (en) | 2021-08-17 |
EP3561410A1 (en) | 2019-10-30 |
JP6745909B2 (en) | 2020-08-26 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP3568650B1 (en) | Oil management for micro booster supermarket refrigeration system | |
EP3088819B1 (en) | Air conditioning device | |
KR100878819B1 (en) | Air conditioner and control method for the same | |
US9631826B2 (en) | Combined air-conditioning and hot-water supply system | |
US10401047B2 (en) | Refrigeration cycle apparatus | |
JP5819000B2 (en) | Refrigeration equipment | |
WO2017038161A1 (en) | Refrigeration cycle device and refrigeration cycle device control method | |
JP6029879B2 (en) | Heat pump type heating device | |
WO2014091909A1 (en) | Heat pump-type heating device | |
JP4920717B2 (en) | Refrigeration equipment | |
US20190301778A1 (en) | Refrigeration cycle apparatus | |
US20170089614A1 (en) | Refrigeration device | |
CN102620458A (en) | Refrigeration cycle apparatus | |
WO2014038028A1 (en) | Refrigerating device | |
JP2012083010A (en) | Refrigeration cycle device | |
US10627138B2 (en) | Air-conditioning apparatus with return oil flow controlled through solenoid valves | |
JP2007127353A (en) | Air-conditioner | |
JP4884432B2 (en) | Refrigeration cycle apparatus and method for operating refrigeration cycle apparatus | |
JP5975742B2 (en) | Refrigeration equipment | |
JP2017116136A (en) | Air conditioner | |
JP2014202399A (en) | Refrigerator | |
WO2018025363A1 (en) | Refrigerating device | |
JP5764029B2 (en) | Heat pump water heater and refrigeration cycle | |
JP6833065B2 (en) | Refrigeration equipment and outdoor unit | |
JP2015169347A (en) | Heat pump device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: MITSUBISHI ELECTRIC CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ITO, MASAHIRO;REEL/FRAME:049303/0399 Effective date: 20190312 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: FINAL REJECTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: FINAL REJECTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE AFTER FINAL ACTION FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: ADVISORY ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: FINAL REJECTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: FINAL REJECTION MAILED |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |