Abstract: A multiroom air conditioner has a plurality of indoor heat exchangers connected to a single outdoor heat exchanger. A reversible expansion valve is installed on a liquid-side branch pipe for each of the indoor heat exchangers, and a solenoid valve is installed on a gas-side branch pipe for each indoor heat exchanger. Temperature sensors are provided on the liquid-side branch pipes, on the gas-side branch pipes, and on the outlet side during cooling of the outdoor heat exchanger. A pressure sensor or a temperature sensor detects the saturation temperature on the high-pressure side of the compressor. Based on the saturation temperature on the high-pressure side of the compressor, the temperature on the outlet side during cooling of the outdoor heat exchanger, and the temperatures in the liquidside branch pipes, a controller controls the expansion valves so as to obtain a target degree of subcooling during cooling and heating.

Abstract: A control device for refrigeration cycle constructed with a compressor, a condenser, an electrically operated expansion valve, an evaporator, and so forth, all being connected in series, wherein there are further provided a by-pass extending from an inlet or an outlet or both of the expansion valve upto an inlet of the compressor through a capillary tube; a first temperature sensor to sense a temperature of a cooling medium at the inlet of the compressor; a second temperature sensor to sense a temperature of the cooling medium within an intake tubing, through which the cooling medium is taken into the inlet of the compressor; and a control device which calculates a super-heat quantity of the cooling medium taken into the compressor on the basis of a difference between the detection outputs of the first and second temperature sensors, and controls a degree of opening of the electrically operated expansion valve, thereby enabling the refrigeration cycle to be operated at high efficiency and in an energy-saving