(19)
(11) EP 2 525 170 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Mention of the grant of the patent:
15.04.2020 Bulletin 2020/16

(21) Application number: 12167765.2

(22) Date of filing: 11.05.2012
(51) International Patent Classification (IPC): 
F25B 43/02(2006.01)
F25B 31/00(2006.01)

(54)

Controlling method for an air conditioner.

Steuerverfahren für eine Klimaanlage

Procédé pour controller un climatiseur


(84) Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30) Priority: 19.05.2011 KR 20110047170

(43) Date of publication of application:
21.11.2012 Bulletin 2012/47

(73) Proprietor: LG Electronics Inc.
Yeongdeungpo-Gu Seoul 07336 (KR)

(72) Inventors:
  • Yoon, Pilhyun
    641-110 Kyungsangnam-do (KR)
  • Sa, Yongcheol
    641-110 Kyungsangnam-do (KR)

(74) Representative: Plasseraud IP 
66, rue de la Chaussée d'Antin
75440 Paris Cedex 09
75440 Paris Cedex 09 (FR)


(56) References cited: : 
EP-A1- 1 657 505
EP-A2- 1 659 351
WO-A1-2009/054571
EP-A1- 1 659 350
EP-A2- 2 204 621
WO-A2-2008/044807
   
       
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    1. Field of the invention



    [0001] The present invention relates to a controlling method for an air conditioner, and more particularly, for an air conditioner in which a plurality of compressors retains a constant oil level.

    2. Description of the Related Art



    [0002] Generally, an air conditioner is an apparatus to cool and/or heat an indoor space via heat exchange between indoor air and a refrigerant that undergoes a refrigerant cycle including compression, condensation, expansion and evaporation. Air conditioners may be classified into a cooling air conditioner to supply cold air to a room by driving a refrigerant cycle in a given direction, and a cooling and heating air conditioner to supply cold air or warm air to a room by driving a refrigerant cycle selectively and bidirectionally.

    [0003] In addition, air conditioners may be classified into a general air conditioner in which a single indoor unit is connected to a single outdoor unit, and a multi-type air conditioner in which a plurality of indoor units is connected to at least one outdoor unit.

    [0004] The multi-type air conditioner is typically used to selectively control, e.g., the temperature of a plurality of spaces partitioned in a building. To this end, in the multi-type air conditioner, a required number of a plurality of compressors may be selectively operated according to the entire air conditioning load. In particular, if the compressors are inverter compressors, adjusting a compression capability thereof is possible.

    [0005] When operating a plurality of inverter compressors together, the respective compressors have different oil discharge rates according to operating modes thereof and thus, have a difference in the level of oil. A shortage of oil may cause compressor failure due to insufficient oil supply, whereas an oversupply of oil may increase power consumption of an internal motor of the compressor, resulting in efficiency deterioration. For this reason, retaining a plurality of compressors at a constant oil level is an important problem.

    [0006] WO 2008/044807 A2 discloses a controlling method for an air conditioner having the features in the preamble of claim 1.

    SUMMARY OF THE INVENTION



    [0007] Therefore, the present invention has been made in view of the above problems, and it is one object of the present invention to provide a controlling method for an air conditioner in which a plurality of compressors retains a constant oil level.

    [0008] Effects of the present invention are not limited to the aforementioned effects, and other effects not mentioned above will be clearly understood by those skilled in the art from the disclosure of the accompanying claims.

    [0009] In accordance with the present invention, the above and other objects can be accomplished by a method having the features of claim 1.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0010] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

    FIG. 1 is a diagram illustrating the configuration of a first air conditioner suitable for the controlling method of the present invention;

    FIG. 2 is a partial detailed diagram of a second air conditioner suitable for the controlling method of the present invention; and

    FIG. 3 is a partial detailed diagram of a third air conditioner suitable for the controlling method of the present invention.


    DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS



    [0011] The advantages and features of the present invention and the way of attaining them will become apparent with reference to embodiments described below in detail in conjunction with the accompanying drawings. Embodiments, however, may be embodied in many different forms and should not be constructed as being limited to example embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be through and complete and will fully convey the scope to those skilled in the art. The scope of the present invention should be defined by the claims. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

    [0012] Hereinafter, an air conditioner in accordance with the embodiments of the present invention will be described in detail with reference to the accompanying drawings.

    [0013] FIG. 1 is a diagram illustrating the configuration of an air conditioner in accordance with an embodiment of the present invention.

    [0014] An outdoor unit OU includes a compressor 110, an outdoor heat exchanger 140, an outdoor expansion valve 132, and a supercooler 180. The air conditioner may include a single or a plurality of outdoor units OU and, in the present embodiment, a single outdoor unit OU is provided.

    [0015] The compressor 110 serves to compress an introduced low-temperature and low-pressure refrigerant into a high-temperature and high-pressure refrigerant. The compressor 110 may have one of various configurations, and an inverter compressor or a constant-speed compressor may be adopted. In the present embodiment, the outdoor unit OU includes a plurality of compressors 110 and more particularly, a plurality of inverter compressors, a compression capability of which is variable according to an operating mode thereof. In the present embodiment, two inverter compressors 110 are provided.

    [0016] An accumulator 187 may be connected to suction pipes 162 of the compressors 110, to prevent a liquid-phase refrigerant from entering the compressors 110.

    [0017] The plurality of compressors 110 is connected respectively to a plurality of refrigerant discharge pipes 172, from which the compressed refrigerant is discharged. The plurality of refrigerant discharge pipes 172 is connected respectively to a plurality of oil separators 171, which separate oil from the discharged refrigerant. The refrigerant having passed through the plurality of oil separators 171 is guided to a 4-way valve 160 through a plurality of discharge pipes 161. Detailed configurations of the plurality of compressors 110 and the plurality of oil separators 171 will be described later with reference to FIG. 2.

    [0018] The 4-way valve 160 is a flow-path switching valve to switch the flow of a refrigerant upon cooling and heating. The 4-way valve 160 may guide a refrigerant compressed in the compressors 110 to the outdoor heat exchanger 140 through an inflow pipe 168 during a cooling operation, or may guide the compressed refrigerant to an indoor heat exchanger 120 through a gas pipe 169 during a heating operation. The 4-way valve 160 is located in a state B during the cooling operation and is located in a state A during the heating operation.

    [0019] The gas pipe 169 guides a refrigerant evaporated in the indoor heat exchanger 120 to the 4-way valve 160 during the cooling operation, enabling the flow of the refrigerant to the compressors 110. Also, the gas pipe 169 guides the refrigerant compressed in the compressors 110 to flow to the indoor heat exchanger 120 by way of the 4-way valve 160 during the heating operation.

    [0020] The outdoor heat exchanger 140 is placed in an outdoor space and a refrigerant passing through the outdoor heat exchanger 140 exchanges heat with outdoor air. The outdoor heat exchanger 140 functions as a condenser during the cooling operation and functions as an evaporator during the heating operation. The outdoor heat exchanger 140 is connected to a liquid pipe 165 via an outflow pipe 166.

    [0021] The outdoor expansion valve 132 serves to throttle an introduced refrigerant during the heating operation and is installed on the outflow pipe 166. A first bypass pipe 167 is installed to the outflow pipe 166 to allow the refrigerant to bypass the outdoor expansion valve 132 and in turn, a check valve 133 is installed on the first bypass pipe 167.

    [0022] The check valve 133 allows the refrigerant to flow from the outdoor heat exchanger 140 to a plurality of indoor units IU during the cooling operation, but interrupts the flow of the refrigerant during the heating operation.

    [0023] The supercooler 180 includes a supercooling heat exchanger 184, a second bypass pipe 181, a supercooling expansion valve 182 and a discharge pipe 185. The supercooling heat exchanger 184 is located on the outflow pipe 166. During the cooling operation, the second bypass pipe 181 may function to bypass a refrigerant discharged from the supercooling heat exchanger 184, directing the refrigerant into the supercooling expansion valve 182.

    [0024] The supercooling expansion valve 182 is located on the second bypass pipe 181 and serves to throttle a liquid-phase refrigerant introduced into the second bypass pipe 181 so as to lower a pressure and temperature of the refrigerant and thereafter, direct the resulting refrigerant into the supercooling heat exchanger 184. The supercooling expansion valve 182 is any one of various types and a linear expansion valve may be adopted for user convenience.

    [0025] During the cooling operation, the supercooling heat exchanger 184 performs heat exchange between a condensed refrigerant having passed through the outdoor heat exchanger 140 and a low-temperature refrigerant directed from the second bypass pipe 181, whereby the resulting supercooled refrigerant flows to the plurality of indoor units IU through the liquid pipe 165.

    [0026] After the refrigerant having passed through the second bypass pipe 181 is heat exchanged in the supercooling heat exchanger 184, the refrigerant is introduced into the accumulator 187 through the discharge pipe 185.

    [0027] In the air conditioner in accordance with the embodiment of the present invention, the plurality of indoor units IU each includes the indoor heat exchanger 120, an indoor blower 125, and an indoor expansion valve 131. The air conditioner may include a single or a plurality of indoor units U and, in the present embodiment, a first indoor unit IU(1) to a third indoor unit IU(3) are provided.

    [0028] The indoor heat exchanger 120 is placed in an indoor space and a refrigerant passing through the indoor heat exchanger 120 exchanges heat with indoor air. The indoor heat exchanger 120 functions as an evaporator during the cooling operation and functions as a condenser during the heating operation. The indoor heat exchanger 120 is connected to the gas pipe 169 via an indoor exit pipe 164 and is connected to the liquid pipe 165 via an indoor entrance pipe 163.

    [0029] The indoor blower 125 serves to blow the indoor air heat exchanged in the indoor heat exchanger 120.

    [0030] The indoor entrance pipe 163 is provided with an indoor expansion valve 131. The indoor expansion valve 131 serves to throttle an introduced refrigerant during the cooling operation. The indoor expansion valve 131 is installed to the indoor entrance pipe 163 of the indoor unit IU. The indoor expansion valve 131 is any one of various types and a linear expansion valve may be adopted for user convenience.

    [0031] FIG. 2 is a partial detailed diagram of an air conditioner in accordance with one embodiment of the present invention.

    [0032] The air conditioner in accordance with one embodiment of the present invention includes the plurality of compressors 110 to compress a refrigerant, the plurality of oil separators 171 connected respectively to the plurality of compressors 110 to separate oil contained in the compressed refrigerant discharged from the compressors 110, a plurality of oil return pipes 177 through which the oil separated in the plurality of oil separators 171 is returned to the plurality of compressors 110, a plurality of oil return valves 176 installed respectively to the plurality of oil return pipes 177 to open or close the plurality of oil return pipes 177 respectively, and a resistor 175 to connect the plurality of oil return pipes 177 to each other.

    [0033] The plurality of compressors 110 compresses an introduced low-temperature and low-pressure refrigerant into a high-temperature and high-pressure refrigerant as described above. In the present embodiment, the plurality of compressors 110 includes a first compressor 110(1) and a second compressor 110(2). The first compressor 110(1) and the second compressor 110(2) are preferably inverter compressors, a compression capability of which is variable according to an operating mode thereof.

    [0034] The compressor 110 includes a refrigerant inlet port 111 into which a refrigerant is introduced, a refrigerant outlet port 112 from which the compressed refrigerant is discharged, an oil level sensor 113 to measure the height of oil within the compressor 110, and an oil pump 114 to forcibly introduce the oil into the compressor 110.

    [0035] The refrigerant inlet port 111 serves to receive a refrigerant to be introduced into the compressor 110 and is connected to the suction pipe 162. The refrigerant inlet port 111 receives a refrigerant, having passed through the accumulator 187, from the suction pipe 162. The first compressor 110(1) includes a first refrigerant inlet port 111(1) and the second compressor 110(2) includes a second refrigerant inlet port 111(2).

    [0036] The refrigerant outlet port 112 serves to discharge the refrigerant compressed in the compressor 110. The refrigerant outlet port 112 is connected to the refrigerant discharge pipe 172. The refrigerant outlet port 112 also discharges oil from the compressor 110 simultaneously with discharge of the compressed refrigerant. The refrigerant containing the oil, discharged from the refrigerant outlet port 112, flows to the oil separator 171 through the refrigerant discharge pipe 172. The first compressor 110(1) includes a first refrigerant outlet port 112(1) and the second compressor 110(2) includes a second refrigerant outlet port 112(2).

    [0037] The oil level sensor 113 measures the height of oil within the compressor 110. The compressor 110 accommodates oil therein and the oil serves to lubricate and cool a mechanical device required to compress a refrigerant. The oil fills a bottom region of the compressor 110 and is pumped during driving of the compressor 110. The oil level sensor 113 measures the height of oil filling the bottom region of the compressor 110. Whether to open or close the oil return valve 176 is determined according to the height of oil measured by the oil level sensor 113. The first compressor 110(1) includes a first oil level sensor 113(1) and the second compressor 110(2) includes a second oil level sensor 113(2).

    [0038] The oil pump 114 is connected to the oil return pipe 177 to introduce the oil into the compressor 110. The oil pump 114 is placed within the compressor 110 to fill the bottom region of the compressor 110 with the oil. The oil pump 114 is preferably located lower than the oil level sensor 113 within the compressor 110. The first compressor 110(1) includes a first oil pump 114(1) and the second compressor 110(2) includes a second oil pump 114(2).

    [0039] Preferably, the oil pump 114 is a trochoid pump to propel oil. The oil pump 114 is preferably provided in the case of a high-pressure compressor and may be omitted in the case of a low-pressure compressor. If the compressor 110 is a low-pressure compressor, preferably, the oil return pipe 177 is directly connected to the compressor 110.

    [0040] Alternatively, the oil pump 114 may be integrally formed within the compressor 110 to pump oil upward from the bottom of the compressor 110, other than being provided separately. The pump is preferably a trochoid pump to propel oil upward. As the oil is propelled upward within the compressor 110, additional oil is suctioned from the oil return pipe 177 into the compressor 110. In this case, the oil return pipe 177 is not directly connected to the oil pump 114.

    [0041] The oil separator 171 separates the oil contained in the refrigerant discharged from the compressor 110. The plurality of oil separators 171 is provided to correspond respectively to the plurality of compressors 110. The plurality of oil separators 171 includes a first oil separator 171(1) corresponding to the first compressor 110(1) and a second oil separator 171(2) corresponding to the second compressor 110(2).

    [0042] The oil separator 171 and the compressor 110 are connected to the refrigerant discharge pipe 172. The plurality of refrigerant discharge pipes 172 is provided to correspond respectively to the plurality of compressors 110. The plurality of refrigerant discharge pipes 172 is connected respectively to the refrigerant outlet ports 112 of the plurality of compressors 110. The plurality of refrigerant discharge pipes 172 includes a first refrigerant discharge pipe 172(1) to connect the first compressor 110(1) and the first oil separator 171(1) to each other and a second refrigerant discharge pipe 172(2) to connect the second compressor 110(2) and the second oil separator 171(2) to each other.

    [0043] The refrigerant, from which the oil has been separated in the oil separator 171, is discharged into a discharge pipe 161. A plurality of discharge pipes 161 is provided and is connected respectively to the plurality of oil separators 171. The plurality of discharge pipes 161 includes a first discharge pipe 161(1) connected to the first oil separator 171(1) and a second discharge pipe 161(2) connected to the second oil separator 171(2).

    [0044] The oil separated in the oil separator 171 is discharged into an oil discharge pipe 173. The oil discharge pipe 173 is diverged into the oil return pipe 177 and an oil confluence pipe 174. The oil discharge pipe 173 is preferably provided with a check valve to prevent backflow of oil.

    [0045] A plurality of oil discharge pipes 173 is provided and is connected respectively to the plurality of oil separators 171 so as to discharge the oil separated in the plurality of oil separators 171 respectively. The plurality of oil discharge pipes 173 includes a first oil discharge pipe 173(1) connected to the first oil separator 171(1) and a second oil discharge pipe 173(2) connected to the second oil separator 171(2).

    [0046] The oil return pipe 177 is a pipe, through which the oil separated in the oil separator 171 flows and is returned to the compressor 110. The oil return pipe 177 connects the oil discharge pipe 173 and the compressor 110 to each other. The oil return pipe 177 may be connected to the compressor 110 so as to be directly connected to the oil pump 114.

    [0047] A plurality of oil return pipes 177 is provided and is connected respectively to the plurality of oil discharge pipes 173. The plurality of oil return pipes 177 includes a first oil return pipe 177(1) to connect the first oil discharge pipe 173(1) and the first compressor 110(1) to each other, and a second oil return pipe 177(2) to connect the second oil discharge pipe 173(2) and the second compressor 110(2) to each other

    [0048] The oil return valve 176 is installed to the oil return pipe 177 to open or close the oil return pipe 177. The oil return valve 176 allows or interrupts return of the oil separated in the oil separator 171 to the compressor 110. The oil return valve 176 is controlled by the oil level sensor 113. More specifically, the oil level sensor 130 controls the oil return valve 176 to open the oil return pipe 177 if the level of oil within the corresponding compressor 110 is lower than the oil level sensor 113, and to close the return pipe 177 if the level of oil within the corresponding compressor 110 is higher than the oil level sensor 113.

    [0049] A plurality of oil return valves 176 is provided. The oil return valves 176 include a first oil return valve 176(1) installed to the first oil return pipe 177(1) and a second oil return valve 176(2) installed to the second oil return pipe 177(2).

    [0050] The first oil return valve 176(1) is opened if the level of oil within the first compressor 110(1) is lower than the first oil level sensor 113(1) and is closed if the level of oil is higher than the first oil level sensor 113(1). Likewise, the second oil return valve 176(2) is opened if the level of oil within the second compressor 110(2) is lower than the second oil level sensor 113(2) and is closed if the level of oil is higher than the second oil level sensor 113(2).

    [0051] The resistor 175 connects the plurality of oil return pipes 177 to each other. More specifically, the resistor 175 connects the first oil return pipe 177(1) and the second oil return pipe 177(2) to each other. The resistor 175 is connected to the oil return pipes 177 via the oil confluence pipes 174.

    [0052] A plurality of oil confluence pipes 174 is provided and is respectively connected at one end thereof to the plurality of oil discharge pipes 173 and at the other end thereof to the resistor 175. The plurality of oil confluence pipes 174 includes a first oil confluence pipe 174(1) to connect the first oil return pipe 177(1) and the resistor 175 to each other and a second oil confluence pipe 174(2) to connect the second oil return pipe 177(2) and the resistor 175 to each other.

    [0053] The first oil confluence pipe 174(1) allows the oil separated in the first oil separator 171(1) to flow to the second oil return pipe 177(2), and the second oil confluence pipe 174(2) allows the oil separated in the second oil separator 171(2) to flow to the first oil return pipe 177(1).

    [0054] The resistor 175 preferably takes the form of a capillary element to prevent confluence of the oil from the plurality of oil return pipes 177 when all of the plurality of oil return valves 176 is opened. If only one of the plurality of oil return valves 176 is opened and the other one is closed, the resistor 175 allows the oil discharged from the plurality of oil discharge pipes 173 to flow together into the oil return pipe 177 to which the opened return valve 176 is installed.

    [0055] Hereinafter, operation of the air conditioner having the above described configuration in accordance with the present invention will be described.

    [0056] The refrigerant compressed in the plurality of compressors 110 is discharged through the respective refrigerant outlet ports 112 along with the oil. The refrigerant and the oil, discharged from the refrigerant outlet ports 112 of the plurality of compressors 110, are introduced into the plurality of oil separators 171 through the plurality of refrigerant discharge pipes 172.

    [0057] The plurality of oil separators 171 separates the refrigerant and the oil from each other. The refrigerant, from which the oil has been separated in the plurality of oil separators 171, is discharged into the plurality of discharge pipes 161. The oil separated in the plurality of oil separators 171 is discharged into the plurality of oil discharge pipes 173.

    [0058] The oil discharged into the plurality of oil discharge pipes 173 exhibits different flow behaviors according to the height of oil within the compressors 110 measured by the oil level sensors 113.

    [0059] If the height of oil within the first compressor 110(1) is lower than the first oil level sensor 113(1) and the height of oil within the second compressor 110(2) is higher than the second oil level sensor 113(2), the first oil return valve 176(1) is opened and the second oil return valve 176(2) is closed. In this case, the oil separated in the plurality of oil separators 171 is wholly returned into the first compressor 110(1). That is, the first oil pump 114(1) is operated to return the oil separated in the first oil separator 171(1) into the first compressor 110(1) by way of the first oil discharge pipe 173(1) and the first oil return pipe 177(1). The first oil pump 114(1) is also operated to return the oil separated in the second oil separator 171(2) into the first compressor 110(1) by way of the second oil discharge pipe 173(2), the second oil confluence pipe 174(2), the resistor 175, the first oil confluence pipe 174(1) and the first oil return pipe 177(1).

    [0060] If the height of oil within the first compressor 110(1) is higher than the first oil level sensor 113(1) and the height of oil within the second compressor 110(2) is lower than the second oil level sensor 113(2), the first oil return valve 176(1) is closed and the second oil return valve 176(2) is opened. In this case, the oil separated in the plurality of oil separators 171 is wholly returned into the second compressor 110(2). That is, the second oil pump 114(2) is operated to return the oil separated in the second oil separator 171(2) into the second compressor 110(2) by way of the second oil discharge pipe 173(3) and the second oil return pipe 177(2). Also, the second oil pump 114(2) is operated to return the oil separated in the first oil separator 171(1) into the second compressor 110(2) by way of the first oil discharge pipe 173(1), the first oil confluence pipe 174(1), the resistor 175, the second oil confluence pipe 174(2) and the second oil return pipe 177(2).

    [0061] If the height of oil within the first compressor 110(1) is lower than the first oil level sensor 113(1) and the height of oil within the second compressor 110(2) is lower than the second oil level sensor 113(2), the first oil return valve 176(1) is opened and the second oil return valve 176(2) is also opened. In this case, since the resistor 175 prevents confluence of the oil returned from the plurality of oil return pipes 177, the oil separated in the plurality of oil separators 171 is returned to the respective corresponding compressors 110.

    [0062] Although the oil separated in the first oil separator 171(1) may flow to the first oil confluence pipe 174(1) through the first oil discharge pipe 173(1), this flow of the oil is limited by the resistor 175 and thus, by operation of the first oil pump 114(1), the oil is returned into the first compressor 110(1) through the first oil return pipe 177(1) in an open state of the first oil return valve 176(1). Also, although the oil separated in the second oil separator 171(2) may flow to the second oil confluence pipe 174(2) through the second oil discharge pipe 173(2), this flow of the oil is limited by the resistor 175 and thus, by operation of the second oil pump 114(2), the oil is returned into the second compressor 110(2) through the second oil return pipe 177(2) in an open state of the second oil return valve 176(2).

    [0063] FIG. 3 is a partial detailed diagram of an air conditioner in accordance with another embodiment of the present invention.

    [0064] In the air conditioner of the present embodiment, a plurality of oil return pipes 277 is connected respectively to the refrigerant inlet ports 111 of the plurality of compressors 110. The plurality of oil return pipes 277 includes a first oil return pipe 277(1) connected to the first refrigerant inlet port 111(1) of the first compressor 110(1) and a second oil return pipe 277(2) connected to the second refrigerant inlet port 111(2) of the second compressor 110(2).

    [0065] The refrigerant inlet port 111 is connected to both the oil return pipe 277 and the suction pipe 162. Thus, the refrigerant moved from the accumulator 187 to the suction pipe 162 and the oil moved from the oil separator 171 to the oil return pipe 277 are introduced into the refrigerant inlet port 111.

    [0066] In this case, the compressor 110 is a low-pressure compressor and does not need the oil pump 114.

    [0067] In some embodiments, the plurality of oil return pipes 277 may be connected to the accumulator 187.

    [0068] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.


    Claims

    1. A controlling method for an air conditioner,
    wherein the air conditioner comprises:

    a first compressor (110(1)) and a second compressor (110(2)) configured to compress a refrigerant;

    a first oil separator (171(1)) connected to the first compressor (110(1)) and serving to separate oil contained in the refrigerant compressed in and discharged from the first compressor (110(1));

    a second oil separator (171(2)) connected to the second compressor (110(2)) and serving to separate oil contained in the refrigerant compressed in and discharged from the second compressor (110(2));

    a first oil return pipe (177(1)) configured to allow the oil separated in the first oil separator (171(1)) to be returned into the first compressor (110(1)) and/or the second compressor (110(2));

    a second oil return pipe (177(2)) configured to allow the oil separated in the second oil separator (171(2)) to be returned into the first compressor (110(1)) and/or the second compressor (110(2));

    a first oil return valve (176(1)) installed to the first oil return pipe (177(1)) to open or close the first oil return pipe (177(1));

    a second oil return valve (176(2)) installed to the second oil return pipe (177(2)) to open or close the second oil return pipe (177(2)); and

    a capillary element (175) configured to connect the first oil return pipe (177(1)) and the second oil return pipe (177(2)) to each other,

    wherein the first compressor (110(1)) comprises a first oil level sensor (113(1)) configured to measure the height of oil within the first compressor (110(1)), and the second compressor (110(2)) comprises a second oil level sensor (113(2)) configured to measure the height of oil within the second compressor (110(2)),

    wherein all of first compressor (110(1)) and the second compressor (110(2)) are inverter compressors, a compression capability of which is variable according to an operating mode thereof,

    characterized in that the controlling method further comprising:

    opening the first oil return valve (176(1)) and the second oil return valve (176(2)) such that the capillary element (175) prevents confluence of the oil returned from the first oil return pipe (177(1)) and the second oil return pipe (177(2)), the oil separated in the first oil separator (171(1)) to be returned into the first compressor (110(1)) and the oil separated in the second oil separator (171(2)) to be returned into the second compressor (110(2)), when the height of oil within the first compressor (110(1)) is lower than the first oil level sensor (113(1)) and the height of oil within the second compressor (110(2)) is lower than the second oil level sensor (113(2));

    opening the first oil return valve (176(1)) and closing the second oil return valve (176(2)) such that the capillary element (175) allows the oil separated in the second oil separator (171(2)) to flow to the first oil return pipe (177(1)), and the oil separated in the first oil separator (171(1)) and the second oil separator (171(2)) to be returned into the first compressor (110(1)), when the height of oil within the first compressor (110(1)) is lower than the first oil level sensor (113(1)) and the height of oil within the second compressor (110(2)) is higher than the second oil level sensor (113(2)); and

    closing the first oil return valve (176(1)) and opening the second oil return valve (176(2)) such that the capillary element (175) allows the oil separated in the first oil separator (171(1)) to flow to the second oil return pipe (177(2)), and the oil separated in the first oil separator (171(1)) and the second oil separator (171(2)) to be returned into the second compressor (110(2)), when the height of oil within the first compressor (110(1)) is higher than the first oil level sensor (113(1)) and the height of oil within the second compressor (110(2)) is lower than the second oil level sensor (113(2)).


     
    2. The controlling method according to claim 1, wherein the air conditioner further comprises:

    a first oil discharge pipe (173(1)) connected to the first oil separator (171(1)) such that the oil separated in the first oil separator (171(1)) are discharged into the first oil discharge pipe (173(1)); and

    a second oil discharge pipe (173(2)) connected to the second oil separator (171(2)) such that the oil separated in the second oil separator (171(2)) are discharged into the second oil discharge pipe (173(2)).


     
    3. The controlling method according to claim 2, wherein the first oil return pipe (177(1)) is connected to the first oil discharge pipe (173(1)) and the second oil return pipe (177(2)) is connected to the second oil discharge pipe (173(2)).
     
    4. The controlling method according to claim 2, wherein the air conditioner further comprises:

    a first oil confluence pipe (174(1)) connected to the first oil discharge pipe (173(1)); and

    a second oil confluence pipe (174(2)) connected to the second oil discharge pipe (173(2)),

    wherein the first oil confluence pipe (174(1)) and the second oil confluence pipe (174(2)) are connected to the capillary element (175).


     
    5. The controlling method according to claim 1, wherein the first compressor (110(1)) further comprises a first oil pump (114(1)) connected to the first oil return pipe (177(1)) to introduce the oil into the first compressor (110(1)) and the second compressor (110(2)) further comprises a second oil pump (114(2)) connected to the second oil return pipe (177(2)) to introduce the oil into the second compressor (110(2)).
     
    6. The controlling method according to claim 5, wherein the first oil pump (114(1)) is placed within the first compressor (110(1)) and the second oil pump (114(2)) is placed within the second compressor (110(2)).
     
    7. The controlling method according to claim 1, wherein:

    the first compressor (110(1)) further comprises a first refrigerant inlet port (111(1)) into which the refrigerant is introduced, and the second compressor (110(2)) further comprises a second refrigerant inlet port (111(2)) into which the refrigerant is introduced; and

    the first oil return pipe (177(1)) is connected to the first refrigerant inlet port (111(1)) and the second oil return pipe (177(2)) is connected to the second refrigerant inlet port (111(2)).


     
    8. The controlling method according to claim 7, wherein:

    the first compressor (110(1)) further comprises a first refrigerant outlet port (112(1)) from which the compressed refrigerant is discharged and the second compressor (110(2)) further comprises a second refrigerant outlet port (112(2)) from which the compressed refrigerant is discharged; and

    the air conditioner further comprises a first refrigerant discharge pipe (172(1)) connected to the first refrigerant outlet port (112(1)) of the first compressor (110(1)) and a second refrigerant discharge pipe (172(2)) connected to the second refrigerant outlet port (112(2)) of the second compressor (110(2)).


     
    9. The controlling method according to claim 1, further comprising:

    a first discharge pipe (161(1)) connected to the first oil separator (171(1)) such that the refrigerant, from which the oil has been separated in the first oil separator (171(1)), is be discharged into the first discharge pipe (161(1)); and

    a second discharge pipe (161(2)) connected to the second oil separator (171(2)) such that the refrigerant, from which the oil has been separated in the second oil separator (171(2)), is be discharged into the second discharge pipe (161(2)).


     


    Ansprüche

    1. Steuerverfahren für eine Klimaanlage,
    wobei die Klimaanlage aufweist:

    einen ersten Verdichter (110(1)) und einen zweiten Verdichter (110(2)) zum Verdichten eines Kältemittels;

    einen ersten Ölseparator (171(1)), der mit dem ersten Verdichter (110(1)) verbunden ist und dazu dient, Öl zu separieren, das in dem in dem ersten Verdichter (110(1)) verdichteten und daraus ausgespeisten Kältemittel enthalten ist;

    einen zweiten Ölseparator (171(2)), der mit dem zweiten Verdichter (110(2)) verbunden ist und dazu dient, Öl zu separieren, das in dem in dem zweiten Verdichter (110(2)) verdichteten und daraus ausgespeisten Kältemittel enthalten ist;

    ein erstes Ölrücklaufrohr (177(1)), das konfiguriert ist, ein Zurückführen des in dem ersten Ölseparator (171(1)) separierten Öls in den ersten Verdichter (110(1)) und/oder den zweiten Verdichter (110(2)) zu erlauben;

    ein zweites Ölrücklaufrohr (177(2)), das konfiguriert ist, ein Zurückführen des in dem zweiten Ölseparator (171(2)) separierten Öls in den ersten Verdichter (110(1)) und/oder den zweiten Verdichter (110(2)) zu erlauben;

    ein an dem ersten Ölrücklaufrohr (177(1)) angebrachtes erstes Ölrücklaufventil (176(1)) zum Öffnen oder zum Schließen des ersten Ölrücklaufrohrs (177(1));

    ein an dem zweiten Ölrücklaufrohr (177(2)) angebrachtes zweites Ölrücklaufventil (176(2)) zum Öffnen oder zum Schließen des zweiten Ölrücklaufrohrs (177(2)); und

    ein Kapillarelement (175), das konfiguriert ist, das erste Ölrücklaufrohr (177(1)) und das zweite Ölrücklaufrohr (177(2)) miteinander zu verbinden,

    wobei der erste Verdichter (110(1)) einen ersten Ölpegelsensor (113(1)) aufweist, der konfiguriert ist, den Ölstand in dem ersten Verdichter (110(1)) zu messen, und der zweite Verdichter (110(2)) einen zweiten Ölpegelsensor (113(2)) aufweist, der konfiguriert ist, den Ölstand in dem zweiten Verdichter (110(2)) zu messen,

    wobei der erste Verdichter (110(1)) und der zweite Verdichter (110(2)) Umkehrverdichter sind, deren Verdichtungsvermögen gemäß ihrem Betriebsmodus variabel ist,

    dadurch gekennzeichnet, dass das Steuerverfahren ferner aufweist:

    Öffnen des ersten Ölrücklaufventils (176(1)) und des zweiten Ölrücklaufventils (176(2)), so dass das Kapillarelement (175) ein Zusammenfließen des aus dem ersten Ölrücklaufrohr (177(1)) und dem zweiten Ölrücklaufrohr (177(2)) zurückfließenden Öls, des in dem ersten Ölseparator (171(1)) separierten und in den ersten Verdichter (110(1)) zurückzuführenden Öls und des in dem zweiten Ölseparator (171(2)) separierten und in den zweiten Verdichter (110(2)) zurückzuführenden Öls verhindert, wenn der Ölstand in dem ersten Verdichter (110(1)) niedriger als der erste Ölpegelsensor (113(1)) ist und der Ölstand in dem zweiten Verdichter (110(2)) niedriger als der zweite Ölpegelsensor (113(2)) ist;

    Öffnen des ersten Ölrücklaufventils (176(1)) und Schließen des zweiten Ölrücklaufventils (176(2)), so dass das Kapillarelement (175) ein Fließen des in dem zweiten Ölseparator (171(2)) separierten Öls zu dem ersten Ölrücklaufrohr (177(1)) und ein Zurückführen des in dem ersten Ölseparator (171(1)) und dem zweiten Ölseparator (171(2)) separierten Öls in den ersten Verdichter (110(1)) erlaubt, wenn der Ölstand in dem ersten Verdichter (110(1)) niedriger als der erste Ölpegelsensor (113(1)) ist und der Ölstand in dem zweiten Verdichter (110(2)) höher als der zweite Ölpegelsensor (113(2)) ist; und

    Schließen des ersten Ölrücklaufventils (176(1)) und Öffnen des zweiten Ölrücklaufventils (176(2)), so dass das Kapillarelement (175) ein Fließen des in dem ersten Ölseparator (171(1)) separierten Öls zu dem zweiten Ölrücklaufrohr (177(2)) und ein Zurückführen des in dem ersten Ölseparator (171(1)) und dem zweiten Ölseparator (171(2)) separierten Öls in den zweiten Verdichter (110(2)) erlaubt, wenn der Ölstand in dem ersten Verdichter (110(1)) höher als der erste Ölpegelsensor (113(1)) ist und der Ölstand in dem zweiten Verdichter (110(2)) niedriger als der zweite Ölpegelsensor (113(2)) ist.


     
    2. Steuerverfahren nach Anspruch 1, wobei die Klimaanlage ferner aufweist:

    ein erstes Ölausspeiserohr (173(1)), das mit dem ersten Ölseparator (171(1)) verbunden ist, so dass das in dem ersten Ölseparator (171(1)) separierte Öl in das erste Ölausspeiserohr (173(1)) ausgespeist wird; und

    ein zweites Ölausspeiserohr (173(2)), das mit dem zweiten Ölseparator (171(2)) verbunden ist, so dass das in dem zweiten Ölseparator (171(2)) separierte Öl in das zweite Ölausspeiserohr (173(2)) ausgespeist wird.


     
    3. Steuerverfahren nach Anspruch 2, wobei das erste Ölrücklaufrohr (177(1)) mit dem ersten Ölausspeiserohr (173(1)) verbunden ist und das zweite Ölrücklaufrohr (177(2)) mit dem zweiten Ölausspeiserohr (173(2)) verbunden ist.
     
    4. Steuerverfahren nach Anspruch 2, wobei die Klimaanlage ferner aufweist:

    ein mit dem ersten Ölausspeiserohr (173((1)) verbundenes erstes Ölzusammenflussrohr (174(1)); und

    ein mit dem zweiten Ölausspeiserohr (173((2)) verbundenes zweites Ölzusammenflussrohr (174(2)),

    wobei das erste Ölzusammenflussrohr (174(1)) und das zweite Ölzusammenflussrohr (174(2)) mit dem Kapillarelement (175) verbunden sind.


     
    5. Steuerverfahren nach Anspruch 1, wobei der erste Verdichter (110(1)) ferner eine erste Ölpumpe (114(1)) aufweist, die mit dem ersten Ölrücklaufrohr (177(1)) verbunden ist, um das Öl in den ersten Verdichter (110(1)) einzuspeisen, und der zweite Verdichter (110(2)) ferner eine zweite Ölpumpe (114(2)) aufweist, die mit dem zweiten Ölrücklaufrohr (177(2)) verbunden ist, um das Öl in den zweiten Verdichter (110(2)) einzuspeisen.
     
    6. Steuerverfahren nach Anspruch 5, wobei die erste Ölpumpe (114(1)) in dem ersten Verdichter (110(1)) angeordnet ist und die zweite Ölpumpe (114(2)) in dem zweiten Verdichter (110(2)) angeordnet ist.
     
    7. Steuerverfahren nach Anspruch 1, wobei:

    der erste Verdichter (110(1)) ferner eine erste Kältemitteleinlassöffnung (111(1)) aufweist, in die das Kältemittel eingespeist wird, und der zweite Verdichter (110(2)) ferner eine zweite Kältemitteleinlassöffnung (111(2)) aufweist, in die das Kältemittel eingespeist wird; und

    das erste Ölrücklaufrohr (177(1)) mit der ersten Kältemitteleinlassöffnung (111(1)) verbunden ist und das zweite Ölrücklaufrohr (177(2)) mit der zweiten Kältemitteleinlassöffnung (111(2)) verbunden ist.


     
    8. Steuerverfahren nach Anspruch 7, wobei:

    der erste Verdichter (110(1)) ferner eine erste Kältemittelauslassöffnung (112(1)) aufweist, aus der das verdichtete Kältemittel ausgespeist wird, und der zweite Verdichter (110(2)) ferner eine zweite Kältemittelauslassöffnung (112(2)) aufweist, aus der das verdichtete Kältemittel ausgespeist wird; und

    die Klimaanlage ferner aufweist: ein erstes Kältemittelausspeiserohr (172(1)), das mit der ersten Kältemittelauslassöffnung (112(1)) des ersten Verdichters (110(1)) verbunden ist, und ein zweites Kältemittelausspeiserohr (172(2)), das mit der zweiten Kältemittelauslassöffnung (112(2)) des zweiten Verdichters (110(2)) verbunden ist.


     
    9. Steuerverfahren nach 1, ferner aufweisend:

    ein erstes Ausspeiserohr (161(1)), das mit dem ersten Ölseparator (171(1)) verbunden ist, so dass das Kältemittel, aus dem in dem ersten Ölseparator (171(1)) das Öl separiert worden ist, in das erste Ausspeiserohr (161(1)) ausgespeist wird; und

    ein zweites Ausspeiserohr (161(2)), das mit dem zweiten Ölseparator (171(2)) verbunden ist, so dass das Kältemittel, aus dem in dem zweiten Ölseparator (171(2)) das Öl separiert worden ist, in das zweite Ausspeiserohr (161(2)) ausgespeist wird.


     


    Revendications

    1. Procédé de commande d'un climatiseur,
    dans lequel le climatiseur comprend :

    un premier compresseur (110(1)) et un second compresseur (110(2)) configurés pour comprimer un fluide frigorigène ;

    un premier séparateur d'huile (171(1)) raccordé au premier compresseur (110(1)) et servant à séparer une huile contenue dans le fluide frigorigène comprimé dans et déchargé du premier compresseur (110(1));

    un second séparateur d'huile (171(2)) raccordé au second compresseur (110(2)) et servant à séparer une huile contenue dans le fluide frigorigène comprimé dans et déchargé du second compresseur (110(2)) ;

    un premier tuyau de retour d'huile (177(1)) configuré pour permettre à l'huile séparée dans le premier séparateur d'huile (171(1)) d'être retournée dans le premier compresseur (110(1)) et/ou dans le second compresseur (110(2)) ;

    un second tuyau de retour d'huile (177(2)) configuré pour permettre à l'huile séparée dans le second séparateur d'huile (171(2)) d'être retournée dans le premier compresseur (110(1)) et/ou dans le second compresseur (110(2)) ;

    une première vanne de retour d'huile (176(1)) installée au premier tuyau de retour d'huile (177(1)) pour ouvrir ou fermer le premier tuyau de retour d'huile (177(1)) ;

    une seconde vanne de retour d'huile (176(2)) installée au second tuyau de retour d'huile (177(2)) pour ouvrir ou fermer le second tuyau de retour d'huile (177(2)) ; et

    un élément capillaire (175) configuré pour raccorder le premier tuyau de retour d'huile (177(1)) et le second tuyau de retour d'huile (177(2)) l'un à l'autre,

    dans lequel le premier compresseur (110(1)) comprend un premier capteur de niveau d'huile (113(1)) configuré pour mesurer la hauteur d'huile à l'intérieur du premier compresseur (110(1)), et le second compresseur (110(2)) comprend un second capteur de niveau d'huile (113(2)) configuré pour mesurer la hauteur d'huile à l'intérieur du second compresseur (110(2)),

    dans lequel tous des premier compresseur (110(1)) et second compresseur (110(2)) sont des compresseurs à inverseur dont une capacité de compression est variable en fonction d'un mode de fonctionnement de ceux-ci,

    caractérisé en ce que le procédé de commande comprend en outre :

    l'ouverture de la première vanne de retour d'huile (176(1)) et de la seconde vanne de retour d'huile (176(2)) de sorte que l'élément capillaire (175) empêche une confluence de l'huile retournée du premier tuyau de retour d'huile (177(1)) et du second tuyau de retour d'huile (177(2)), de l'huile séparée dans le premier séparateur d'huile (171(1)) à retourner dans le premier compresseur (110(1)) et de l'huile séparée dans le second séparateur d'huile (171(2)) à retourner dans le second compresseur (110(2)), lorsque la hauteur d'huile à l'intérieur du premier compresseur (110(1)) est plus basse que le premier capteur de niveau d'huile (113(1)) et la hauteur d'huile à l'intérieur du second compresseur (110(2)) est plus basse que le second capteur de niveau d'huile (113(2)) ;

    l'ouverture de la première vanne de retour d'huile (176(1)) et la fermeture de la seconde vanne de retour d'huile (176(2)) de sorte que l'élément capillaire (175) permette à l'huile séparée dans le second séparateur d'huile (171(2)) de s'écouler jusqu'au premier tuyau de retour d'huile (177(1)), et à l'huile séparée dans le premier séparateur d'huile (171(1)) et dans le second séparateur d'huile (171(2)) d'être retournée dans le premier compresseur (110(1)), lorsque la hauteur d'huile à l'intérieur du premier compresseur (110(1)) est plus basse que le premier capteur de niveau d'huile (113(1)) et la hauteur d'huile à l'intérieur du second compresseur (110(2)) est plus haute que le second capteur de niveau d'huile (113(2)) ; et

    la fermeture de la première vanne de retour d'huile (176(1)) et l'ouverture de la seconde vanne de retour d'huile (176(2)) de sorte que l'élément capillaire (175) permette à l'huile séparée dans le premier séparateur d'huile (171(1)) de s'écouler jusqu'au second tuyau de retour d'huile (177(2)), et à l'huile séparée dans le premier séparateur d'huile (171(1)) et dans le second séparateur d'huile (171(2)) d'être retournée dans le second compresseur (110(2)), lorsque la hauteur d'huile à l'intérieur du premier compresseur (110(1)) est plus haute que le premier capteur de niveau d'huile (113(1)) et la hauteur d'huile à l'intérieur du second compresseur (110(2)) est plus basse que le second capteur de niveau d'huile (113(2)).


     
    2. Procédé de commande selon la revendication 1, dans lequel le climatiseur comprend en outre :

    un premier tuyau de décharge d'huile (173(1)) raccordé au premier séparateur d'huile (171(1)) de sorte que l'huile séparée dans le premier séparateur d'huile (171(1)) soit déchargée dans le premier tuyau de décharge d'huile (173(1)) ; et

    un second tuyau de décharge d'huile (173(2)) raccordé au second séparateur d'huile (171(2)) de sorte que l'huile séparée dans le second séparateur d'huile (171(2)) soit déchargée dans le second tuyau de décharge d'huile (173(2)).


     
    3. Procédé de commande selon la revendication 2, dans lequel le premier tuyau de retour d'huile (177(1)) est raccordé au premier tuyau de décharge d'huile (173(1)) et le second tuyau de retour d'huile (177(2)) est raccordé au second tuyau de décharge d'huile (173(2)).
     
    4. Procédé de commande selon la revendication 2, dans lequel le climatiseur comprend en outre :

    un premier tuyau de confluence d'huile (174(1)) raccordé au premier tuyau de décharge d'huile (173(1)) ; et

    un second tuyau de confluence d'huile (174(2)) raccordé au second tuyau de décharge d'huile (173(2)),

    dans lequel le premier tuyau de confluence d'huile (174(1)) et le second tuyau de confluence d'huile (174(2)) sont raccordés à l'élément capillaire (175).


     
    5. Procédé de commande selon la revendication 1, dans lequel le premier compresseur (110(1)) comprend en outre une première pompe à huile (114(1)) raccordée au premier tuyau de retour d'huile (177(1)) pour introduire l'huile dans le premier compresseur (110(1)) et le second compresseur (110(2)) comprend en outre une seconde pompe à huile (114(2)) raccordée au second tuyau de retour d'huile (177(2)) pour introduire l'huile dans le second compresseur (110(2)).
     
    6. Procédé de commande selon la revendication 5, dans lequel la première pompe à huile (114(1)) est placée à l'intérieur du premier compresseur (110(1)) et la seconde pompe à huile (114(2)) est placée à l'intérieur du second compresseur (110(2)).
     
    7. Procédé de commande selon la revendication 1, dans lequel :

    le premier compresseur (110(1)) comprend en outre un premier orifice d'entrée de fluide frigorigène (111(1)) dans lequel le fluide frigorigène est introduit, et le second compresseur (110(2)) comprend en outre un second orifice d'entrée de fluide frigorigène (111(2)) dans lequel le fluide frigorigène est introduit ; et

    le premier tuyau de retour d'huile (177(1)) est raccordé au premier orifice d'entrée de fluide frigorigène (111(1)) et le second tuyau de retour d'huile (177(2)) est raccordé au second orifice d'entrée de fluide frigorigène (111(2)).


     
    8. Procédé de commande selon la revendication 7, dans lequel :

    le premier compresseur (110(1)) comprend en outre un premier orifice de sortie de fluide frigorigène (112(1)) duquel le fluide frigorigène comprimé est déchargé et le second compresseur (110(2)) comprend en outre un second orifice de sortie de fluide frigorigène (112(2)) duquel le fluide frigorigène comprimé est déchargé ; et

    le climatiseur comprend en outre un premier tuyau de décharge de fluide frigorigène (172(1)) raccordé au premier orifice de sortie de fluide frigorigène (112(1)) du premier compresseur (110(1)) et un second tuyau de décharge de fluide frigorigène (172(2)) raccordé au second orifice de sortie de fluide frigorigène (112(2)) du second compresseur (110(2)).


     
    9. Procédé de commande selon la revendication 1, comprenant en outre :

    un premier tuyau de décharge (161(1)) raccordé au premier séparateur d'huile (171(1)) de sorte que le fluide frigorigène, duquel l'huile a été séparée dans le premier séparateur d'huile (171(1)), soit déchargé dans le premier tuyau de décharge (161(1)) ; et

    un second tuyau de décharge (161(2)) raccordé au second séparateur d'huile (171(2)) de sorte que le fluide frigorigène, duquel l'huile a été séparée dans le second séparateur d'huile (171(2)), soit déchargé dans le second tuyau de décharge (161(2)).


     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description