Abstract: An air conditioner includes a compressor; an outdoor heat exchanger; an indoor heat exchanger; an outdoor fan configured to supply outdoor air to the outdoor heat exchanger; and an indoor fan configured to supply indoor air to the indoor heat exchanger. The air conditioner performs a heating operation by driving both the indoor fan and the outdoor fan and by causing refrigerant to flow in one direction through both the indoor heat exchanger and the outdoor heat exchanger and so that a defrost operation in which both the indoor fan and the outdoor fan are stopped is performed by causing the refrigerant to flow in the opposite direction to that in the heating operation. When a defrost failure is caused by the defrost operation the outdoor fan is driven, and the indoor fan is stopped for a predetermined period of time, after which the defrost operation is resumed.

Abstract: A parallel-flow type heat exchanger (1) is provided with two vertical-direction header pipes (2, 3), and a plurality of horizontal-direction flat tubes (4) that connect the header pipes with each other. The plurality of horizontal direction flat tubes are divided into a plurality of groups each comprising a plurality of flat tubes, and each of the groups constitutes a coolant path that lets coolant flow from one vertical-direction header pipe to the other. The upper limit for the number of flat tubes that constitute a coolant path for one turn is obtained from a prescribed numerical formula.

Abstract: A heat exchanger (20) is provided with: two header pipes (21, 22) which are disposed parallel to each other with a space therebetween; a plurality of flat tubes (23) which are disposed between the header pipes, refrigerant passages (24) provided therein communicating with the interiors of the header pipes; and fins (25) which are disposed between the flat tubes. The plurality of flat tubes are divided into two parts: an upper group (27) located in the upper part; and a lower group (28) located in the lower part. The flat tubes of the upper group and parts corresponding thereto of the header pipes constitute an upper heat exchange part (40), and the flat tubes of the lower group and parts corresponding thereto of the header pipes constitute a lower heat exchange part (41).

Abstract: An air conditioner (1) includes: a compressor (21); an outdoor heat exchanger (23); an indoor heat exchanger (13); an outdoor fan (25); and an indoor fan (15). In a case where the outdoor heat exchanger (23) has frost, the indoor fan (15) and the outdoor fan (25) are stopped, and a refrigerant is flowed in a direction opposite to a warming operation so as to perform a defrosting operation. In a case where a temperature of the refrigerant output from the compressor (21) declines below a predetermined temperature during the defrosting operation, it is determined to be defective defrosting. In a case of the defective defrosting by the defrosting operation, the outdoor fan (25) is driven, the indoor fan (15) is stopped and the refrigerant is flowed in a same direction as the warming operation so as to perform a defrosting preparation operation. Thereafter, the defrosting operation is resumed.

Abstract: A heat exchanger (1) includes: two vertical header pipes (2, 3) which are arranged apart in parallel; a plurality of flat tubes (4) which are arranged between the header pipes and in which refrigerant passages (5) provided therewithin communicate with an interior of the header pipes; and corrugated fins (6) which are arranged between the flat tubes. The flat tubes are configured to form one or more turns. In the header pipe on the refrigerant piping connection side, a temperature sensor (11) for sensing the temperature of a refrigerant is arranged at a location through which the refrigerant in a gas-liquid two-phase state flows. The temperature sensor is attached to the header pipe with a metal fitting (12).

Abstract: A heat exchanger 1A has: two header pipes 2 and 3 arranged parallel at an interval; a plurality of flat tubes 4 arranged between the header pipes 2 and 3 with refrigerant passages 5 inside them communicating with the inside of the header pipes 2 and 3; and corrugated fins 6 arranged between adjacent flat tubes 4. To outward facing flat surfaces of, of the plurality of flat tubes 4, those located outermost, outermost corrugated fins 6a having pleats in the shape of a louver are fitted.