Abstract: An air conditioning apparatus includes a compressor, an interior side heat exchanger, an exterior side heat exchanger, an expansion device provided between the interior side heat exchanger and the exterior side heat exchanger, a four-way valve provided between the compressor and the interior side heat exchanger and between the compressor and the exterior side heat exchanger, an oil separator provided between a delivery outlet of the compressor and the four-way valve, a first restrictor and a second restrictor provided between the oil separator and a suction inlet of the compressor, and an open-close valve provided between the second restrictor and the suction inlet of the compressor.

Abstract: A multi-room type air-conditioner includes one outdoor apparatus and two or more indoor apparatuses which are respectively connected to the outdoor apparatus through respective electric expansion valves. The number of the indoor apparatuses to be connected is detected by a connection number detecting device, the closing degrees of the electric expansion valves are determined by the ratio of the loads of the respective indoor apparatuses and the frequency of the compressor is determined by a predetermined algorithmic expression of a relation between the loads of the respective indoor apparatuses which includes the rated capacities of the respective indoor apparatuses. Thereby, the air-conditioning operations for heating and cooling desired areas are optimally performed.