An air conditioner is provided. The air conditioner may include at least one indoor device, an electric heat pump (EHP) outdoor device connected with the at least one indoor device, and having a first compressor driven using electric power and a first outdoor heat exchanger, and a gas heat pump (GHP) outdoor device connected with the at least one indoor device, and having an engine that drives a second compressor using a combustion gas and a second outdoor heat exchanger. The GHP outdoor device may include an exhaust gas heat exchanger that performs heat exchange between a refrigerant flowing through the EHP outdoor device and an exhaust gas of the engine.

A heat exchanger according to the present invention includes a heat exchanging unit, and a distributing and joining unit connected to the heat exchanging unit and including a distributing flow passage and a joining flow passage. The distributing and joining unit separately includes a first header including the distributing flow passage formed therein and excluding the joining flow passage, and a second header juxtaposed to the first header and including the joining flow passage formed therein and excluding the distributing flow passage. At least one of the first header and the second header is a stacking type header including a plurality of plate-like members including partial flow passages formed therein and stacked so that the partial flow passages are communicated with each other to form the distributing flow passage or the joining flow passage.

An air conditioner includes a heat storage apparatus for storing heat emitted from a compressor arranged in an outdoor unit, wherein the heat storage apparatus includes a heat storage tank installed in the compressor for storing heat emitted from the compressor and a heat transfer member configured to deliver heat emitted from the compressor to the heat storage tank, wherein the heat storage tank includes a first heat transfer face configured to have a form corresponding to a part of an outer circumferential face of the compressor to come into contact with the outer circumferential face of the compressor and a pair of second heat transfer faces configured to extend from both ends of the first heat transfer face to be in parallel to each other and form space with the outer circumferential face of the compressor, and wherein the heat transfer member is arranged in the space.

A determination device includes a refrigerant circuit, an operation determination unit, and a refrigerant determination unit. The refrigerant circuit is made of a compressor, a condenser, an expansion mechanism, and an evaporator that are circularly connected. In a refrigeration cycle operation in accordance with a quantity of heat required by the condensers or the evaporators, the operation determination unit determines whether the refrigeration cycle operation can be normally carried out or not. Upon determination that the refrigeration cycle operation cannot be normally carried out, the refrigerant determination unit determines whether a refrigerant in the refrigerant circuit is regenerable or not, based on a result of the determination. Thus the determination device is provided by which an effort involved with determination as to whether the refrigerant is regenerable or not can be reduced.

Provided is an air-conditioning apparatus including a switching valve and a bypass circuit. The switching valve is provided between an expansion valve and an outdoor heat exchanger. The bypass circuit has a first end connected to a refrigerant pipe connecting a compressor and an indoor heat exchanger to each other, and a second end connected to the switching valve. During a heating operation, the air-conditioning apparatus causes a rotating member of the switching valve to rotate to sequentially connect, to the bypass circuit, flow passages of the outdoor heat exchanger connected in parallel, to thereby defrost the outdoor heat exchanger while performing the heating operation.

A low-cost and highly-efficient air-conditioning system including an AHU using refrigerant of a heat pump cycle as a heat source, and capable of reducing an on/off cycle operation of compressors at a time of a low load, the system including: a plurality of outdoor units; an air handling unit; a plurality of independent heat pump cycles formed by connecting the plurality of outdoor units and the air handling unit by refrigerant pipes, each of the plurality of independent heat pump cycles including a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger; and a number control unit controlling, to satisfy a capacity demand corresponding to an air-conditioning load, based on a particular frequency range associated with the compressor, in which a certain compressor efficiency or more is obtained, a number of the compressors in operation and operating frequencies of the respective compressors in operation.

An outdoor device for an air conditioner is provided that may include a compressor that compresses a refrigerant, a condenser that condenses the refrigerant compressed in the compressor, an expansion device that decompresses the refrigerant condensed in the condenser, an evaporator that evaporates the refrigerant decompressed in the expansion device, and a refrigerant storage that bypasses at least a portion of the refrigerant condensed in the condenser to store the bypassed refrigerant therein. The refrigerant storage may include a first storage that stores the bypassed refrigerant, and a second storage in which the refrigerant passing through the evaporator is introduced. The second storage may discharge a gaseous refrigerant of the introduced refrigerant to the compressor. The first storage may be provided above the second storage to supply the refrigerant stored therein into the second storage.

An air conditioner for conditioning a space inside a building comprises a heat source unit and at least one indoor unit. The heat source unit has a heat exchanger unit comprising a first heat exchanger disposed in a first casing and configured to exchange heat with a heat source and a compressor unit comprising a compressor disposed in a second casing separate from the first casing. The at least one indoor unit has a second heat exchanger configured to exchange heat with the space to be conditioned and being fluidly communicated to the heat exchanger unit and/or the compressor unit. The heat exchanger unit is disposed inside the building and fluidly communicated to the outside of the building.

An outdoor unit, connected with indoor units by pipes to constitute a refrigerant circuit, includes a compressor configured to compress and discharge refrigerant, a plurality of parallel heat exchangers configured to allow heat exchange between air and the refrigerant, a first defrosting pipe serving as a flow path for branching a part of the refrigerant discharged by the compressor and allowing the refrigerant to flow into the parallel heat exchanger to be defrosted for defrosting, a first expansion device configured to decompress the refrigerant passing through the first defrosting pipe, a second expansion device configured to adjust the pressure of the refrigerant that passed through the parallel heat exchanger to be defrosted, and a controller configured to control the second expansion device such that the pressure of the refrigerant that passed through the parallel heat exchanger to be defrosted falls within a predetermined range.

Provided is a heat-pump system including a plurality of compressors, wherein the plurality of compressors includes a first compressor and a second compressor that compress refrigerant, an oil separator provided on a discharge side of the plurality of compressors to separate oil mixed with refrigerant compressed by the plurality of compressors, an oil separation pipe extended from the oil separator to allow the plurality of compressors to recover oil, and a compressor side oil balance pipe extended from the second compressor to allow the first compressor to recover oil stored in the second compressor.