Provided are an air conditioner and a method for controlling the same. The air conditioner including a compressor (240), a condenser 8210), an evaporator (220), a receiver (260) for storing at least one portion of a refrigerant passing through the condenser and a gas/liquid separator (270) for filtering a liquid refrigerant of the refrigerant introduced from the receiver to supply a gaseous refrigerant into the compressor includes a first flow rate regulator (261) for controlling the amount of refrigerant supplied into the receiver, a second flow rate regulator (262) for controlling the amount of refrigerant introduced from the receiver into the gas/liquid separator, a first detection unit (264) for detecting the amount of refrigerant stored in the receives and a control unit (290) for controlling an opening degree of the first or second flow rate regulator, based on information of at least one of the amount of refrigerant detected by the first detection unit and the amount of refrigerant circulating in the air conditioner.

To provide a Brayton cycle type refrigerating apparatus using multiple stages of compressors and having a good response without reduction in efficiency due to change in heat load of the object to be cooled, the Brayton cycle type refrigerating apparatus (100) according to the present invention comprises, on a refrigerant line (101), multiple stages of compressors (102a, 102b, 102c), a temperature sensor (160) for detecting heat load of an object to be cooled, and a buffer tank (111) provided between a low pressure line (109) and a high pressure line (110), wherein a flow rate of the refrigerant in the refrigerant line is controlled by controlling opening degrees of valves (112, 113) to adjust the cooling capacity.

A multi type air conditioner comprises: an outdoor unit (10) including an outdoor heat exchanger (12) heat-exchanged with the outdoor air, a compressor (14) compressing a refrigerant, and a first four-way valve (16) and a second four-way valve (18) switching a refrigerant flow path; indoor units (20) performing at least one of cooling operation and heating operation; and a distributor (30) including a low pressure pipe (50) connected between the first four-way valve (16) and each of the indoor units (20), a high pressure pipe (52) connected between the second four-way valve (18) and each of the indoor units (20), and a refrigerant pipe (32) connected between the outdoor heat-exchanger (12) and each of the indoor units (20). Accordingly, flow resistance of a refrigerant is reduced in heating operation, thereby improving heating performance and heating efficiency, and the amount of refrigerant accumulated within a high pressure pipe (52) is minimized in cooling operation, thereby improving cooling performance and cooling efficiency.

A refrigerant circuit (10) operates in a refrigeration cycle in which the pressure of refrigerant discharged from a compressor (22) is at or above the critical pressure. In performing an operation in which a first indoor heat exchanger (33a) performs a heating operation and, concurrently, a second indoor heat exchanger is made inactive, an indoor expansion valve (34b) associated with the inactive indoor heat exchanger (33b) is fully closed.

A heat pump with a compressor (10), indoor and outdoor heat exchangers (20,40) for condensing or evaporating refrigerant compressed by the compressor (10) according to cooling or heating operation mode, a four-way valve (60) for guiding the flow of the compressed refrigerant to the indoor heat exchanger (20) or the outdoor heat exchanger (40) according to the operation mode, an expansion valve (30) for selectively decreasing the pressure of liquid refrigerant according to the operation mode, a check valve (31) selectively opened or closed according to the operation mode for guiding the flow of the liquid refrigerant to the expansion valve (30), an accumulator (50) for preventing the liquid refrigerant from entering into the inlet of the compressor (10), connection pipes (1,2,3), and a heat exchange part (110) for performing heat exchange between the connection pipe connected to the inlet of the accumulator (50) and the connection pipe connected to the indoor heat exchanger (20).

Disclosed is a multi-air conditioner comprising: an outdoor unit A installed at an outdoor location and exchanging heat with an outdoor air, a plurality of indoor units C installed at respective indoor rooms and provided therein with an indoor heat exchanger 31 and an electronic expansion valve 30, and a distributor B provided between the outdoor unit A and the indoor units C, for selectively guiding the refrigerant according to the operation mode. The outdoor unit A is comprised of a compressor 1, a refrigerant flow control part 2 for controlling a flow path of a compressed refrigerant according to an operation mode, an outdoor heat exchanger 3 exchanging heat with the outdoor air, and a pipe part connecting the elements of the outdoor unit A and guiding the refrigerant to the distributor B. The distributor B guides the refrigerant selectively to the outdoor unit A and the indoor units C according to the operation mode.