US20100147018A1 - Refrigeration apparatus - Google Patents
Refrigeration apparatus Download PDFInfo
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- US20100147018A1 US20100147018A1 US12/591,856 US59185609A US2010147018A1 US 20100147018 A1 US20100147018 A1 US 20100147018A1 US 59185609 A US59185609 A US 59185609A US 2010147018 A1 US2010147018 A1 US 2010147018A1
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- Prior art keywords
- compressor
- oil
- suction pipe
- compressors
- discharged
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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
- F25B31/00—Compressor arrangements
- F25B31/002—Lubrication
- F25B31/004—Lubrication oil recirculating 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
- F25B2313/023—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
- 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
- F25B2400/0751—Details of compressors or related parts with parallel compressors the compressors having different capacities
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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
- F25B2500/00—Problems to be solved
- F25B2500/16—Lubrication
Definitions
- the present invention relates to a refrigeration apparatus that is provided with at least two compressors, a first compressor and a second compressor, which are connected in parallel, in an outdoor unit, and is suitable for large buildings such as office buildings and apartment houses. More particularly, it relates to a technique for making the amounts of a refrigerator oil in the compressors approximately equal.
- a so-called multiple air conditioning system has been used in which a refrigerant is supplied from one outdoor unit to a plurality of indoor units installed in the building.
- the outdoor unit is sometimes provided in plural numbers.
- the required air cooling capacity or heating capacity differs depending on the number of operating indoor units. Therefore, to meet this condition, a plurality of compressors are mounted in the outdoor unit.
- the second compressor Up to a predetermined capacity, the second compressor is not operated, and only the first compressor is operated with the rotational speed thereof being controlled by an inverter. In contrast, when a capacity higher than a predetermined value is required, the second compressor of constant-speed type is operated together with the first compressor.
- the discharged oil amount of the scroll compressor is larger, because of construction, than that of the rotary compressor.
- a refrigerant compression section is disposed on the lower side of a motor, and the refrigerant gas generated in the refrigerant compression section passes through a passage or a gap present on the motor side and is discharged through a discharge pipe. Therefore, the refrigerant gas and the refrigerator oil are easily separated from each other.
- the refrigerant compression section is disposed above the motor, so that even in an interior high pressure type, the refrigerant gas generated in the refrigerant compression section scarcely passes through the motor, and is discharged through a discharge pipe.
- an object of the present invention is to provide a refrigeration apparatus in which the amounts of a refrigerator oil in compressors are made approximately equal even in the case where one compressor that is operated by being connected in parallel is a compressor in which the discharged oil amount is small and the other compressor is a compressor in which the discharged oil amount is large.
- the present invention provides a refrigeration apparatus in which an outdoor unit includes at least two compressors, a first compressor and a second compressor, which are connected in parallel with each other; an oil separator is provided in a discharge pipe of each of the compressors; and a first oil separator on the first compressor side is connected to a suction pipe of the second compressor via first oil return piping, and a second oil separator on the second compressor side is connected to a suction pipe of the first compressor via second oil return piping, wherein the amount of discharged oil differs between the first compressor and the second compressor; and an oil storage part of the first compressor in which the amount of discharged oil is small is connected to the suction pipe of the second compressor in which the amount of discharged oil is large.
- a rotary compressor is used as the first compressor, and a scroll compressor is used as the second compressor.
- the outdoor unit includes at least two compressors, the first compressor and the second compressor, which are connected in parallel with each other; the oil separator is provided in a discharge pipe of each of the compressors; and the first oil separator on the first compressor side is connected to the suction pipe of the second compressor via the first oil return piping, and the second oil separator on the second compressor side is connected to the suction pipe of the first compressor via the second oil return piping, the amount of discharged oil differs between the first compressor and the second compressor; and the oil storage part of the first compressor in which the amount of discharged oil is small is connected to the suction pipe of the second compressor in which the amount of discharged oil is large.
- a refrigerator oil is supplied from the first compressor (for example, a rotary compressor) in which the refrigerator oil is present in a relatively large amount to the second compressor (for example, a scroll compressor) in which the amount of discharged oil is large via the oil guiding pipe. Therefore, the amounts of refrigerator oil in the compressors can be made approximately equal.
- the suction pipe of the first compressor and the suction pipe of the second compressor communicate with each other; and the connecting position of the first oil return piping and the oil guiding pipe to the suction pipe of the second compressor be a position at which the refrigerator oil supplied from the first oil return piping and the oil guiding pipe to the second compressor side drops on account of the gravity and is sucked into the first compressor when the second compressor is in a non-operating state.
- FIG. 1 is a refrigerant circuit diagram showing a general configuration of a refrigeration apparatus in accordance with an embodiment of the present invention.
- FIG. 2 is an enlarged view of a compressor section of an outdoor unit included in the refrigeration apparatus shown in FIG. 1 .
- FIGS. 1 and 2 A refrigeration apparatus in accordance with an embodiment of the present invention will now be described with reference to FIGS. 1 and 2 .
- the present invention is not limited to this embodiment.
- this refrigeration apparatus includes an outdoor unit 100 and an indoor unit 200 .
- the outdoor unit 100 includes a compression mechanism section 101 , a four-way valve (directional control valve) 130 , an outdoor heat exchanger 140 having an outdoor fan 141 , an outdoor expansion valve 150 , and an accumulator 160 .
- indoor heat exchangers 210 each having an indoor expansion valve 211 are connected in parallel between liquid-side piping 11 and gas-side piping 12 .
- Each of the indoor heat exchangers 210 is provided with an indoor fan, but the fan is omitted in the figure.
- the compression mechanism section 101 is provided with two compressors, a first compressor 110 and a second compressor 120 that are connected to discharge-side gas piping 13 in parallel.
- the first compressor 110 a variable-speed type rotary compressor in which the rotational speed is variable due to inverter control is used
- the second compressor 120 a constant-speed type scroll compressor in which the rotational speed is constant is used.
- the rotary compressor may be of a single rotor type, a usual twin rotor type, an injection system twin rotor type, or the like type.
- a refrigerant discharge pipe 110 a of the first compressor 110 is connected to the discharge-side gas piping 13 via an oil separator 111 and a check valve 112 .
- a refrigerant discharge pipe 120 a of the second compressor 120 is connected to the discharge-side gas piping 13 via an oil separator 121 and a check valve 122 .
- the oil separator 111 , 121 separates a refrigerator oil contained in a high-pressure discharged gas refrigerant, and the check valve 112 , 122 inhibits the high-pressure discharged gas refrigerant sent from the other compressor from entering the own compressor.
- the accumulator 160 is provided on the refrigerant suction side of the compressors 110 and 120 to return the refrigerant that finished its work. From the accumulator 160 , a main suction pipe 161 for a low-pressure refrigerant gas is led, and a branch pipe 162 is provided in the end part of the main suction pipe 161 .
- the branch pipe 162 is forked into two branches. One branch is connected with a suction pipe 163 for the first compressor 110 , and the other branch is connected with a suction pipe 164 for the second compressor 120 .
- a sub accumulator 113 is provided on the suction side of the first compressor 110 .
- the oil separator 111 on the first compressor 110 side is connected to the suction pipe 164 for the second compressor 120 via oil return piping 114 having a capillary tube 115 serving as a pressure reducing means.
- oil separator 121 on the second compressor 120 side is connected to the suction pipe 163 for the first compressor 110 via oil return piping 124 having a capillary tube 125 serving as a pressure reducing means.
- an oil storage part 110 b of the first compressor (rotary compressor) 110 is connected to the suction pipe 164 of the second compressor (scroll compressor) 120 via an oil guiding pipe 116 including a capillary tube 117 serving as a pressure reducing means.
- the connecting position of the oil return piping 114 and the oil guiding pipe 116 to the suction pipe 164 is a position at which the refrigerator oil supplied from the oil return piping 114 and the oil guiding pipe 116 to the second compressor 120 side can drop on account of the gravity.
- the suction pipe 164 has a tilting part sloping downward toward the branch pipe 162 side, the oil return piping 114 and the oil guiding pipe 116 are connected to this tilting part.
- the suction pipe 163 and the suction pipe 164 communicate with each other in the portion of the branch pipe 162 , when the second compressor 120 is in a non-operating state, the refrigerator oil supplied from the oil return piping 114 and the oil guiding pipe 116 to the second compressor 120 side is sucked into the first compressor 110 , and when the second compressor 120 is in an operating state, the refrigerator oil supplied from the oil return piping 114 and the oil guiding pipe 116 to the second compressor 120 side is sucked into the second compressor 120 directly.
- the four-way valve 130 is switched over to a state indicated by solid lines in FIG. 1 .
- the gas refrigerant discharged from the compression mechanism section 101 is brought from the four-way valve 130 to the outdoor heat exchanger 140 , being heat exchanged with the outside air, and is condensed (at the time of air cooling operation, the outdoor heat exchanger 140 acts as a condenser).
- the liquid refrigerant condensed by the outdoor heat exchanger 140 passes through a check valve 151 connected in parallel to the outdoor expansion valve 150 , and is supplied to the indoor unit 200 .
- the liquid refrigerant is decompressed to a predetermined pressure by the indoor expansion valve 211 , and thereafter is heat exchanged with the indoor air by the indoor heat exchanger 210 to evaporate. Thereby, the indoor air is cooled (at the time of air cooling operation, the indoor heat exchanger 210 acts as an evaporator).
- the gas refrigerant evaporated by the indoor heat exchanger 210 goes into the accumulator 160 via the four-way valve 130 . After the liquid refrigerant has been separated, the gas refrigerant is returned to the compression mechanism section 101 .
- the four-way valve 130 is switched over to a state indicated by chain lines in FIG. 1 .
- the gas refrigerant discharged from the compression mechanism section 101 is brought from the four-way valve 130 to the indoor heat exchanger 210 , being heat exchanged with the indoor air, and is condensed.
- the indoor air is warmed (at the time of air cooling operation, the indoor heat exchanger 210 acts as a condenser).
- the liquid refrigerant condensed by the indoor heat exchanger 210 passes through the indoor expansion valve 211 the valve opening of which is controlled according to the heating capacity, and is supplied to the outdoor unit 100 .
- the liquid refrigerant is decompressed to a predetermined pressure by the outdoor expansion valve 150 , and thereafter is heat exchanged with the outside air by the outdoor heat exchanger 140 to evaporate (at the time of heating operation, the outdoor heat exchanger 140 acts as an evaporator).
- the gas refrigerant evaporated by the outdoor heat exchanger 140 goes into the accumulator 160 via the four-way valve 130 . After the liquid refrigerant has been separated, the gas refrigerant is returned to the compression mechanism section 101 .
- the refrigerator oil separated by the oil separator 111 on the first compressor 110 side and the refrigerator oil in the oil storage part 110 b of the first compressor 110 are supplied to the suction pipe 164 of the second compressor 120 via the oil return piping 114 and via the oil guiding pipe 116 , respectively, and the refrigerator oil separated by the oil separator 121 on the second compressor 120 side is supplied to the suction pipe 163 of the first compressor 110 via the oil return piping 124 .
- the amounts of refrigerator oil in the compressors 110 and 120 are made approximately equal.
- the amount of refrigerator oil discharged together with high-pressure gas is larger in the scroll compressor than in the rotary compressor because of construction for the above-described reason. According to the present invention, however, excess refrigerator oil is supplied to the scroll compressor side of the second compressor 120 via the oil guiding pipe 116 from the rotary compressor side of the first compressor 110 to compensate the discharged oil, so that the deviation of the amounts of refrigerator oil caused by the difference in discharged oil amount between the compressors 110 and 120 can be solved.
- first compressor inverter-controlled rotary compressor
- second compressor constant-speed scroll compressor
- both the two compressors may be compressors of the same compression type (for example, rotary compressors or scroll compressors).
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Applications Or Details Of Rotary Compressors (AREA)
- Rotary Pumps (AREA)
Abstract
In the case where one compressor that is operated by being connected in parallel is a compressor in which the discharged oil amount is small, and the other compressor is a compressor in which the discharged oil amount is large, the amounts of refrigerator oil in the compressors are made approximately equal. In the refrigeration apparatus in which an outdoor unit 100 includes at least two compressors, a first compressor 110 and a second compressor 120, which are connected in parallel with each other; an oil separator 111, 121 is provided in a discharge pipe of each of the compressors 110 and 120; and a first oil separator 111 on the first compressor side is connected to a suction pipe 164 of the second compressor 120 via first oil return piping 114, and a second oil separator 121 on the second compressor side is connected to a suction pipe 163 of the first compressor 110 via second oil return piping 124, a rotary compressor is used as the first compressor 110, and a scroll compressor is used as the second compressor 120; and an oil storage part 110 b of the first compressor 110 is connected to the suction pipe 164 of the second compressor 120 via an oil guiding pipe 118.
Description
- The present application is based on, and claims priority from, Japanese Application Serial Number JP2008-315651, filed Dec. 11, 2008, the disclosure of which is hereby incorporated by reference herein in its entirety.
- The present invention relates to a refrigeration apparatus that is provided with at least two compressors, a first compressor and a second compressor, which are connected in parallel, in an outdoor unit, and is suitable for large buildings such as office buildings and apartment houses. More particularly, it relates to a technique for making the amounts of a refrigerator oil in the compressors approximately equal.
- For air-conditioning equipment for a large building such as an office building and an apartment house, a so-called multiple air conditioning system has been used in which a refrigerant is supplied from one outdoor unit to a plurality of indoor units installed in the building. In the large-scale system of this type, the outdoor unit is sometimes provided in plural numbers.
- In the multiple air conditioning system, the required air cooling capacity or heating capacity differs depending on the number of operating indoor units. Therefore, to meet this condition, a plurality of compressors are mounted in the outdoor unit.
- The case where two compressors are mounted is explained. Usually, as a first compressor, a variable-speed compressor in which the rotational speed is variable due to inverter control is used, and as a second compressor, a constant-speed compressor in which the rotational speed is constant is used.
- Up to a predetermined capacity, the second compressor is not operated, and only the first compressor is operated with the rotational speed thereof being controlled by an inverter. In contrast, when a capacity higher than a predetermined value is required, the second compressor of constant-speed type is operated together with the first compressor.
- Thus, in both of the case where only the first compressor is operated and the case where both of the first and second compressors are operated, the excess and deficiency of a refrigerator oil in the compressors must be prevented.
- As one example of the preventive measures, in the invention described in Patent Document 1 (Japanese Patent Application Publication No. 2001-324230), the oil storage part of the first compressor and the suction pipe of the second compressor are connected to each other via oil return piping, and the oil storage part of the second compressor and the suction pipe of the first compressor are connected to each other via oil return piping.
- According to the invention described in
Patent Document 1, when both of the two compressors are operated, excess refrigerator oil is returned from the first compressor to the second compressor or from the second compressor to the first compressor, and when only one compressor is operated, excess refrigerator oil is returned to the own machine, so that a proper amount of refrigerator oil is held in the compressors. - However, if the discharged oil amount of refrigerator oil (the amount of refrigerator oil discharged together with discharged gas) differs between the compressors, the above-described conventional art cannot achieve the above-described effect in some cases.
- For example, if it is assumed that the inverter controlled first compressor that is operated always is a rotary compressor, and the constant-speed second compressor that is operated when a predetermined or higher capacity is required is a scroll compressor, the discharged oil amount of the scroll compressor is larger, because of construction, than that of the rotary compressor.
- The reason for this is as described below. In the rotary compressor, usually, a refrigerant compression section is disposed on the lower side of a motor, and the refrigerant gas generated in the refrigerant compression section passes through a passage or a gap present on the motor side and is discharged through a discharge pipe. Therefore, the refrigerant gas and the refrigerator oil are easily separated from each other. In contrast, in the scroll compressor, usually, the refrigerant compression section is disposed above the motor, so that even in an interior high pressure type, the refrigerant gas generated in the refrigerant compression section scarcely passes through the motor, and is discharged through a discharge pipe.
- In the case where the amounts of refrigerator oil are deviated by the difference in discharged oil amount between compressors in this manner, the conventional art has a difficulty in solving this difference. In the worst case, oil runs short on account of the lowering of oil level, which may lead to a seizure accident. Even among the same rotary compressors, or among the same scroll compressors, the discharged oil amount may differ.
- Accordingly, an object of the present invention is to provide a refrigeration apparatus in which the amounts of a refrigerator oil in compressors are made approximately equal even in the case where one compressor that is operated by being connected in parallel is a compressor in which the discharged oil amount is small and the other compressor is a compressor in which the discharged oil amount is large.
- To achieve the above object, the present invention provides a refrigeration apparatus in which an outdoor unit includes at least two compressors, a first compressor and a second compressor, which are connected in parallel with each other; an oil separator is provided in a discharge pipe of each of the compressors; and a first oil separator on the first compressor side is connected to a suction pipe of the second compressor via first oil return piping, and a second oil separator on the second compressor side is connected to a suction pipe of the first compressor via second oil return piping, wherein the amount of discharged oil differs between the first compressor and the second compressor; and an oil storage part of the first compressor in which the amount of discharged oil is small is connected to the suction pipe of the second compressor in which the amount of discharged oil is large.
- Preferably, a rotary compressor is used as the first compressor, and a scroll compressor is used as the second compressor.
- According to the present invention, in the refrigeration apparatus in which the outdoor unit includes at least two compressors, the first compressor and the second compressor, which are connected in parallel with each other; the oil separator is provided in a discharge pipe of each of the compressors; and the first oil separator on the first compressor side is connected to the suction pipe of the second compressor via the first oil return piping, and the second oil separator on the second compressor side is connected to the suction pipe of the first compressor via the second oil return piping, the amount of discharged oil differs between the first compressor and the second compressor; and the oil storage part of the first compressor in which the amount of discharged oil is small is connected to the suction pipe of the second compressor in which the amount of discharged oil is large. Thereby, a refrigerator oil is supplied from the first compressor (for example, a rotary compressor) in which the refrigerator oil is present in a relatively large amount to the second compressor (for example, a scroll compressor) in which the amount of discharged oil is large via the oil guiding pipe. Therefore, the amounts of refrigerator oil in the compressors can be made approximately equal.
- In the present invention, it is preferable that the suction pipe of the first compressor and the suction pipe of the second compressor communicate with each other; and the connecting position of the first oil return piping and the oil guiding pipe to the suction pipe of the second compressor be a position at which the refrigerator oil supplied from the first oil return piping and the oil guiding pipe to the second compressor side drops on account of the gravity and is sucked into the first compressor when the second compressor is in a non-operating state.
- According to this configuration, when the second compressor is in a non-operating state, the refrigerator oil supplied from the first oil return piping and the oil guiding pipe to the second compressor side is sucked into the first compressor, and when the second compressor is in an operating state, the refrigerator oil supplied from the first oil return piping and the oil guiding pipe to the second compressor side is sucked into the second compressor as it is.
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FIG. 1 is a refrigerant circuit diagram showing a general configuration of a refrigeration apparatus in accordance with an embodiment of the present invention; and -
FIG. 2 is an enlarged view of a compressor section of an outdoor unit included in the refrigeration apparatus shown inFIG. 1 . - A refrigeration apparatus in accordance with an embodiment of the present invention will now be described with reference to
FIGS. 1 and 2 . The present invention is not limited to this embodiment. - Referring to
FIG. 1 , this refrigeration apparatus includes anoutdoor unit 100 and anindoor unit 200. Theoutdoor unit 100 includes acompression mechanism section 101, a four-way valve (directional control valve) 130, anoutdoor heat exchanger 140 having anoutdoor fan 141, anoutdoor expansion valve 150, and anaccumulator 160. - In the
indoor unit 200, a plurality of (three in this example, for convenience of drawing the figure)indoor heat exchangers 210 each having anindoor expansion valve 211 are connected in parallel between liquid-side piping 11 and gas-side piping 12. Each of theindoor heat exchangers 210 is provided with an indoor fan, but the fan is omitted in the figure. - Referring to
FIG. 2 , according to this embodiment, thecompression mechanism section 101 is provided with two compressors, afirst compressor 110 and asecond compressor 120 that are connected to discharge-side gas piping 13 in parallel. - In this embodiment, as the
first compressor 110, a variable-speed type rotary compressor in which the rotational speed is variable due to inverter control is used, and as thesecond compressor 120, a constant-speed type scroll compressor in which the rotational speed is constant is used. The rotary compressor may be of a single rotor type, a usual twin rotor type, an injection system twin rotor type, or the like type. - A
refrigerant discharge pipe 110 a of thefirst compressor 110 is connected to the discharge-side gas piping 13 via anoil separator 111 and acheck valve 112. Arefrigerant discharge pipe 120 a of thesecond compressor 120 is connected to the discharge-side gas piping 13 via anoil separator 121 and acheck valve 122. - The
oil separator check valve - The
accumulator 160 is provided on the refrigerant suction side of thecompressors accumulator 160, amain suction pipe 161 for a low-pressure refrigerant gas is led, and abranch pipe 162 is provided in the end part of themain suction pipe 161. - The
branch pipe 162 is forked into two branches. One branch is connected with asuction pipe 163 for thefirst compressor 110, and the other branch is connected with asuction pipe 164 for thesecond compressor 120. In this embodiment, since thefirst compressor 110 is the rotary compressor requiring less liquid back amount, asub accumulator 113 is provided on the suction side of thefirst compressor 110. - The
oil separator 111 on thefirst compressor 110 side is connected to thesuction pipe 164 for thesecond compressor 120 viaoil return piping 114 having acapillary tube 115 serving as a pressure reducing means. - Similarly, the
oil separator 121 on thesecond compressor 120 side is connected to thesuction pipe 163 for thefirst compressor 110 viaoil return piping 124 having acapillary tube 125 serving as a pressure reducing means. - Besides, in the present invention, an
oil storage part 110 b of the first compressor (rotary compressor) 110 is connected to thesuction pipe 164 of the second compressor (scroll compressor) 120 via anoil guiding pipe 116 including acapillary tube 117 serving as a pressure reducing means. - The connecting position of the
oil return piping 114 and theoil guiding pipe 116 to thesuction pipe 164 is a position at which the refrigerator oil supplied from theoil return piping 114 and theoil guiding pipe 116 to thesecond compressor 120 side can drop on account of the gravity. For example, in the case where thesuction pipe 164 has a tilting part sloping downward toward thebranch pipe 162 side, theoil return piping 114 and theoil guiding pipe 116 are connected to this tilting part. - According to this configuration, since the
suction pipe 163 and thesuction pipe 164 communicate with each other in the portion of thebranch pipe 162, when thesecond compressor 120 is in a non-operating state, the refrigerator oil supplied from theoil return piping 114 and theoil guiding pipe 116 to thesecond compressor 120 side is sucked into thefirst compressor 110, and when thesecond compressor 120 is in an operating state, the refrigerator oil supplied from theoil return piping 114 and theoil guiding pipe 116 to thesecond compressor 120 side is sucked into thesecond compressor 120 directly. - Next, the operating action of this refrigeration apparatus is explained. When a capacity lower than a predetermined value is required, only the
first compressor 110 is operated while the rotational speed thereof is controlled by an inverter with thesecond compressor 120 being in a non-operating state. In contrast, when a predetermined or higher capacity is required, the constant-speedsecond compressor 120 is operated together with thefirst compressor 110. - At the time of air cooling operation, the four-
way valve 130 is switched over to a state indicated by solid lines inFIG. 1 . Thereby, the gas refrigerant discharged from thecompression mechanism section 101 is brought from the four-way valve 130 to theoutdoor heat exchanger 140, being heat exchanged with the outside air, and is condensed (at the time of air cooling operation, theoutdoor heat exchanger 140 acts as a condenser). - The liquid refrigerant condensed by the
outdoor heat exchanger 140 passes through acheck valve 151 connected in parallel to theoutdoor expansion valve 150, and is supplied to theindoor unit 200. - On the
indoor unit 200 side, the liquid refrigerant is decompressed to a predetermined pressure by theindoor expansion valve 211, and thereafter is heat exchanged with the indoor air by theindoor heat exchanger 210 to evaporate. Thereby, the indoor air is cooled (at the time of air cooling operation, theindoor heat exchanger 210 acts as an evaporator). - The gas refrigerant evaporated by the
indoor heat exchanger 210 goes into theaccumulator 160 via the four-way valve 130. After the liquid refrigerant has been separated, the gas refrigerant is returned to thecompression mechanism section 101. - At the time of heating operation, the four-
way valve 130 is switched over to a state indicated by chain lines inFIG. 1 . Thereby, the gas refrigerant discharged from thecompression mechanism section 101 is brought from the four-way valve 130 to theindoor heat exchanger 210, being heat exchanged with the indoor air, and is condensed. Thereby, the indoor air is warmed (at the time of air cooling operation, theindoor heat exchanger 210 acts as a condenser). - The liquid refrigerant condensed by the
indoor heat exchanger 210 passes through theindoor expansion valve 211 the valve opening of which is controlled according to the heating capacity, and is supplied to theoutdoor unit 100. - On the
outdoor unit 100 side, the liquid refrigerant is decompressed to a predetermined pressure by theoutdoor expansion valve 150, and thereafter is heat exchanged with the outside air by theoutdoor heat exchanger 140 to evaporate (at the time of heating operation, theoutdoor heat exchanger 140 acts as an evaporator). - The gas refrigerant evaporated by the
outdoor heat exchanger 140 goes into theaccumulator 160 via the four-way valve 130. After the liquid refrigerant has been separated, the gas refrigerant is returned to thecompression mechanism section 101. - When both of the first and
second compressors oil separator 111 on thefirst compressor 110 side and the refrigerator oil in theoil storage part 110 b of thefirst compressor 110 are supplied to thesuction pipe 164 of thesecond compressor 120 via the oil return piping 114 and via theoil guiding pipe 116, respectively, and the refrigerator oil separated by theoil separator 121 on thesecond compressor 120 side is supplied to thesuction pipe 163 of thefirst compressor 110 via the oil return piping 124. Thereby, the amounts of refrigerator oil in thecompressors - Comparing the rotary compressor of the
first compressor 110 with the scroll compressor of thesecond compressor 120, the amount of refrigerator oil discharged together with high-pressure gas is larger in the scroll compressor than in the rotary compressor because of construction for the above-described reason. According to the present invention, however, excess refrigerator oil is supplied to the scroll compressor side of thesecond compressor 120 via theoil guiding pipe 116 from the rotary compressor side of thefirst compressor 110 to compensate the discharged oil, so that the deviation of the amounts of refrigerator oil caused by the difference in discharged oil amount between thecompressors - When only the
first compressor 110 is being operated, and the second compressor is not being operated, the refrigerator oil supplied from the oil return piping 114 and theoil guiding pipe 116 to thesecond compressor 120 side is sucked into thefirst compressor 110. - In the above-described embodiments, one first compressor (inverter-controlled rotary compressor) and one second compressor (constant-speed scroll compressor) are combined. However, even in the case where both of the first and second compressors are provided in plural numbers, the present invention can be applied.
- Also, on condition that the discharged oil amount differs, both the two compressors may be compressors of the same compression type (for example, rotary compressors or scroll compressors).
Claims (3)
1. A refrigeration apparatus in which an outdoor unit includes at least two compressors, a first compressor and a second compressor, which are connected in parallel with each other; an oil separator is provided in a discharge pipe of each of the compressors; and a first oil separator on the first compressor side is connected to a suction pipe of the second compressor via first oil return piping, and a second oil separator on the second compressor side is connected to a suction pipe of the first compressor via second oil return piping, wherein
the amount of discharged oil differs between the first compressor and the second compressor; and an oil storage part of the first compressor in which the amount of discharged oil is small is connected to the suction pipe of the second compressor in which the amount of discharged oil is large.
2. The refrigeration apparatus according to claim 1 , wherein the first compressor is a rotary compressor, and the second compressor is a scroll compressor.
3. The refrigeration apparatus according to claim 1 , wherein the suction pipe of the first compressor and the suction pipe of the second compressor communicate with each other; and the connecting position of the first oil return piping and the oil guiding pipe to the suction pipe of the second compressor is a position at which the refrigerator oil supplied from the first oil return piping and the oil guiding pipe to the second compressor side drops on account of the gravity and is sucked into the first compressor when the second compressor is in a non-operating state.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2008315651A JP2010139155A (en) | 2008-12-11 | 2008-12-11 | Refrigeration apparatus |
JP2008-315651 | 2008-12-11 |
Publications (1)
Publication Number | Publication Date |
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US20100147018A1 true US20100147018A1 (en) | 2010-06-17 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/591,856 Abandoned US20100147018A1 (en) | 2008-12-11 | 2009-12-03 | Refrigeration apparatus |
Country Status (5)
Country | Link |
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US (1) | US20100147018A1 (en) |
EP (1) | EP2196747A1 (en) |
JP (1) | JP2010139155A (en) |
CN (1) | CN101749889A (en) |
AU (1) | AU2009248463A1 (en) |
Cited By (2)
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CN102954624A (en) * | 2012-11-27 | 2013-03-06 | 大连三洋压缩机有限公司 | Parallel compressor oil return device and control method |
US20150219372A1 (en) * | 2014-02-05 | 2015-08-06 | Lg Electronics Inc. | Heat-Pump System |
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CN103062948B (en) * | 2012-12-29 | 2015-04-08 | 宁波奥克斯电气有限公司 | Dual parallel compressor screw water chilling unit |
CN103062959A (en) * | 2012-12-29 | 2013-04-24 | 宁波奥克斯电气有限公司 | Oil passage balance system of dual parallel compressor screw water chilling unit |
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JP2016145651A (en) * | 2015-02-06 | 2016-08-12 | 株式会社富士通ゼネラル | Air conditioner |
JP6390796B2 (en) * | 2015-09-01 | 2018-09-19 | 株式会社デンソー | Two-stage boost refrigeration cycle |
WO2018078883A1 (en) * | 2016-10-31 | 2018-05-03 | 三菱電機株式会社 | Refrigeration cycle device |
CN107101419A (en) * | 2017-06-20 | 2017-08-29 | 珠海格力电器股份有限公司 | Compressor return oil system, method for controlling oil return and double compressor system |
WO2019129113A1 (en) * | 2017-12-28 | 2019-07-04 | 艾默生环境优化技术(苏州)有限公司 | Air intake pipe used for compressor system and compressor system |
JP6970363B1 (en) * | 2020-09-30 | 2021-11-24 | ダイキン工業株式会社 | Compressor |
CN113587353B (en) * | 2021-08-16 | 2022-07-08 | 广东积微科技有限公司 | Control method for oil return of multi-split air conditioning system |
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- 2009-12-09 EP EP09252757A patent/EP2196747A1/en not_active Withdrawn
- 2009-12-10 CN CN200910253720A patent/CN101749889A/en active Pending
- 2009-12-11 AU AU2009248463A patent/AU2009248463A1/en not_active Abandoned
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US6287083B1 (en) * | 1999-04-14 | 2001-09-11 | Hitachi, Ltd. | Compressed air production facility |
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CN102954624A (en) * | 2012-11-27 | 2013-03-06 | 大连三洋压缩机有限公司 | Parallel compressor oil return device and control method |
US20150219372A1 (en) * | 2014-02-05 | 2015-08-06 | Lg Electronics Inc. | Heat-Pump System |
US10012419B2 (en) * | 2014-02-05 | 2018-07-03 | Lg Electronics Inc. | Heat-pump system |
Also Published As
Publication number | Publication date |
---|---|
JP2010139155A (en) | 2010-06-24 |
AU2009248463A1 (en) | 2010-07-01 |
EP2196747A1 (en) | 2010-06-16 |
CN101749889A (en) | 2010-06-23 |
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