Abstract: An air conditioner includes at least one compressor, an outlet pipe, an inlet pipe, and at least one bypass pipe. Oil and/or refrigerant discharged from the at least one compressor flows through the outlet pipe. The inlet pipe receives the oil and/or refrigerant flown through the outlet pipe and allows the oil and/or refrigerant to flow to the at least one compressor. The at least one bypass pipe is connected to the at least one compressor and allow bypass flows of the oil and/or refrigerant from the at least one compressor to the outlet pipe.

Abstract: An air conditioner is provided, in which some of a plurality of outdoor heat exchangers implement a defrosting operation and others implement a heating operation. The air conditioner includes a compressor to compress refrigerant, a hot gas pipe to which a part of the refrigerant compressed in the compressor is moved, a 4-way valve to which the remaining refrigerant compressed in the compressor is moved, an indoor heat exchanger in which the refrigerant, having passed through the 4-way valve, undergoes heat exchange with indoor air, and a plurality of outdoor heat exchangers, some of which implement a heating operation as the heat-exchanged refrigerant from the indoor heat exchanger is moved therethrough while others implement a defrosting operation as the refrigerant having passed through the hot gas pipe is moved therethrough.

Abstract: An air conditioner includes a compressor, a first heat exchanger, and a first pipe configured to allow refrigerant to flow from the first heat exchanger. A bypass pipe is branched off from the first pipe and is configured to expand refrigerant flowing through the bypass pipe. A second heat exchanger is configured to allow the expanded refrigerant of the bypass pipe to heat-exchange with the refrigerant flowing along the first pipe. A second pipe couples the second heat exchanger to the compressor so that the refrigerant expanded by the bypass pipe and heat-exchanged at the second heat exchanger can be introduced into the compressor.

Abstract: An air conditioner includes a plurality of compressors, a plurality of oil separators, a plurality of oil collection pipes, a common inlet pipe, and a plurality of branch inlet pipes. The oil separators are connected to outlets of the compressors for separating a refrigerant and/or oil discharged from the compressors. The oil collection pipes are respectively connected to the oil separators for collecting oil separated by the oil separators. The common inlet pipe receives the collected oil and allows the oil to flow to the compressors. The branch inlet pipes branch off from the common inlet pipe and are respectively connected to the compressors.

Abstract: Disclosed is an air conditioner which includes a plurality of compressors, a common inlet pipe through which fluid flows to the compressors, a plurality of inlet pipes branching off from the common inlet pipe which are connected to the compressors, a plurality of outlet pipes connected to the compressors through which refrigerant discharged from the compressors passes, and a plurality of bypass pipes connected to the compressors through which fluid discharged from the compressors passes. The fluid which passes through the plurality of bypass pipes is distributed to the plurality of compressors through the common inlet pipe.

Abstract: An air conditioner including an indoor heat exchange unit to perform a heat exchange process by the supply and absorption of heat through the circulation of a first refrigerant, at least one outdoor heat exchange unit to perform a heat exchange process by the absorption and supply of heat through the circulation of a second refrigerant, and an intermediate connection unit to perform a heat exchange between the first refrigerant and the second refrigerant.

Abstract: An air conditioner includes a compressor, a first heat exchanger, and a first pipe configured to allow refrigerant to flow from the first heat exchanger. A bypass pipe is branched off from the first pipe and is configured to expand refrigerant flowing through the bypass pipe. A second heat exchanger is configured to allow the expanded refrigerant of the bypass pipe to heat-exchange with the refrigerant flowing along the first pipe. A second pipe couples the second heat exchanger to the compressor so that the refrigerant expanded by the bypass pipe and heat-exchanged at the second heat exchanger can be introduced into the compressor.

Abstract: An air conditioner includes a plurality of compressors, a common intake pipe, and a plurality of oil equalizing pipes that connect the compressors to the common intake pipe such that oil existing above a reference oil level in the compressors can be transferred to the common intake pipe. An oil equalizing valve provided on at least two of the oil equalizing pipes controls oil flowing through the oil equalizing pipes, where at least two of the oil equalizing valves can be opened together during performance of oil equalizing operation such that amounts of the oil in at least two compressors can be equalized.

Abstract: An air conditioner, which automatically detects malfunction, and a method for detecting a malfunction thereof are provided. The method includes: measuring an indoor unit pipe temperature around an indoor heat exchanger during operation of the air conditioner; actuating an indoor expansion valve connected to the indoor heat exchanger to a first state; and detecting whether or not a variation of the indoor unit pipe temperature is abnormal by measuring the indoor unit pipe temperature after actuating the indoor expansion valve to the first state.

Abstract: An air conditioner is provided, in which some of a plurality of outdoor heat exchangers implement a defrosting operation and others implement a heating operation. The air conditioner includes a compressor to compress refrigerant, a hot gas pipe to which a part of the refrigerant compressed in the compressor is moved, a 4-way valve to which the remaining refrigerant compressed in the compressor is moved, an indoor heat exchanger in which the refrigerant, having passed through the 4-way valve, undergoes heat exchange with indoor air, and a plurality of outdoor heat exchangers, some of which implement a heating operation as the heat-exchanged refrigerant from the indoor heat exchanger is moved therethrough while others implement a defrosting operation as the refrigerant having passed through the hot gas pipe is moved therethrough.

Abstract: An apparatus for controlling a refrigerant level comprises a first detecting unit installed at a lower side of the inside of a refrigerant tank, for detecting whether a refrigerant stored at a lower side of the inside of the refrigerant is a liquefied refrigerant or a gaseous refrigerant, a second detecting unit installed at an upper side of the inside of the refrigerant tank, for detecting whether a refrigerant stored at an upper side of the inside of the refrigerant tank is a liquefied refrigerant and a gaseous refrigerant, and a control unit controlling intake and discharge of the liquefied refrigerant according to a value measured by the first detecting unit and the second detecting unit.

Abstract: An air conditioner includes a plurality of compressors, a plurality of oil separators, a plurality of oil collection pipes, a common inlet pipe, and a plurality of branch inlet pipes. The oil separators are connected to outlets of the compressors for separating a refrigerant and/or oil discharged from the compressors. The oil collection pipes are respectively connected to the oil separators for collecting oil separated by the oil separators. The common inlet pipe receives the collected oil and allows the oil to flow to the compressors. The branch inlet pipes branch off from the common inlet pipe and are respectively connected to the compressors.

Abstract: An air conditioner includes at least one compressor, an outlet pipe, an inlet pipe, and at least one bypass pipe. Oil and/or refrigerant discharged from the at least one compressor flows through the outlet pipe. The inlet pipe receives the oil and/or refrigerant flown through the outlet pipe and allows the oil and/or refrigerant to flow to the at least one compressor. The at least one bypass pipe is connected to the at least one compressor and allow bypass flows of the oil and/or refrigerant from the at least one compressor to the outlet pipe.

Abstract: Disclosed is an air conditioner which includes a plurality of compressors, a common inlet pipe through which fluid flows to the compressors, a plurality of inlet pipes branching off from the common inlet pipe which are connected to the compressors, a plurality of outlet pipes connected to the compressors through which refrigerant discharged from the compressors passes, and a plurality of bypass pipes connected to the compressors through which fluid discharged from the compressors passes. The fluid which passes through the plurality of bypass pipes is distributed to the plurality of compressors through the common inlet pipe.

Abstract: An air-conditioner having a dual-refrigerant cycle includes a primary refrigerant circuit heat-exchanged with outdoor air; a secondary refrigerant circuit heat-exchanged with indoor air to perform either a cooling operation or a heating operation; and a heat exchange unit disposed between the primary refrigerant circuit and the secondary refrigerant circuit to perform heat exchange therebetween, wherein the secondary refrigerant circuit includes a compressor for compressing a refrigerant circulating in the secondary refrigerant circuit. A condensing pressure of the primary refrigerant circuit is lowered during the hating operation and an evaporation pressure of the primary refrigerant circuit is increased to thereby enhance efficiency of the air-conditioner.

Abstract: An air conditioner including an indoor heat exchange unit to perform a heat exchange process by the supply and absorption of heat through the circulation of a first refrigerant, at least one outdoor heat exchange unit to perform a heat exchange process by the absorption and supply of heat through the circulation of a second refrigerant, and an intermediate connection unit to perform a heat exchange between the first refrigerant and the second refrigerant.

Abstract: An air conditioner including a plurality of compressors uses at least one oil separator for separating oil from an oil-mixed refrigerant discharged from the compressors. The air conditioner performs an oil balancing operation, during which some compressors operate and some do not. At least a portion of the oil separated by the oil separator is distributed to the compressors that are not operating during the oil balancing operation.

Abstract: A second-refrigerant pump driving type air conditioner, including an indoor unit having an indoor heat exchanger that circulates a refrigerant containing no oil, a first circulator including a compressor that compresses and discharges a refrigerant containing oil, a first outdoor heat exchanger, a second outdoor heat exchanger, and an outdoor expander, and a second circulator including an intermediate heat exchanger connected to the indoor heat exchanger that circulates the refrigerant containing no oil and heat-exchanges the refrigerant of the first outdoor heat exchanger, a receiver, and a pump. A restriction of a length and a diameter of a connection pipe for connecting an outdoor unit and the indoor unit is decreased, and an oil shortage of the compressor is prevented.

Abstract: An air conditioning system comprises a first tank connected to an outlet side refrigerant line of an indoor unit, a second tank disposed to be lower than the first tank, middle tank installed between the first tank and the second tank, a heat source cycle for depressurizing and cooling the first refrigerant inside the first tank by circulating a second refrigerant and heating the first refrigerant of the second tank, a middle tank cooling unit for feed back connected to an inlet side refrigerant line of the second tank among refrigerant lines of the heat source cycle, a middle tank heating unit for feed back connected to a refrigerant line between the first tank and the second tank among refrigerant lines of the heat source cycle, and a controller for selectively circulating the second refrigerant of the heat source cycle to the middle tank cooling unit for feed back or the middle tank heating unit for feed back.

Abstract: A multi-air conditioner comprising: a plurality of indoor units for exchanging the heat with indoor air; a plurality of outdoor units, each outdoor unit having an outdoor heat exchanger for exchanging the heat and a compressor for compressing a fluid; a connecting pipe for connecting the indoor units with the outdoor units; and a pressure equalizing pipe for communicating the outdoor heat exchanger of one outdoor unit with the compressor of at least one other outdoor unit, so that the multi-air conditioner is capable of improving stability, reliability and efficiency of a system by equalizing the low pressure between the indoor units in heating and equalizing the high pressure between the outdoor units in cooling.