Abstract: In a refrigerating machine having a heat exchanger, a rated compressor for which the frequency of driving power is fixed, a power control mechanism which is disposed in the compressor and serves to return a part of the refrigerant in the cylinder under a compressing process to the cylinder under sucking process, a refrigerant return mechanism for returning a part of the refrigerant discharged from the compressor to a refrigerant suction side of the compressor, and a controller for selectively controlling the power control mechanism and the refrigerant return mechanism to make the output power variable. A pole-changeable type compressor having a pole changer may be used in place of the rated compressor having the power control mechanism, and the output power is made variable by selectively controlling the pole changer and the refrigerant return mechanism.

Abstract: In a multiroom air conditioner and a method of driving a multiroom air conditioner containing plural outdoor side units each containing a compressor, an outdoor fan, an outdoor heat exchanger and a refrigerant path change-over valve, plural indoor side units each containing an indoor heat exchanger, and an inter-unit pipe comprising a high-pressure gas pipe, a low-pressure gas pipe and a liquid pipe through which the plural outdoor side units are connected to the indoor side units to thereby form a refrigerant cycle, and in which each individual indoor side unit independently and selectively performs a room cooling operation or a room heating operation for an individual room, when a stop signal is output to some outdoor side unit in accordance with an indoor load during a room cooling or heating operation, the refrigerant path change-over valve of the outdoor unit is switched and the outdoor fan thereof is driven so that the driving of the compressor of the outdoor side unit is stopped, but refrigerant is all

Abstract: In a multiroom air-conditioning apparatus, refrigerant flow between plural outdoor side units is controlled so that abnormality (lack or excess) of refrigerant amount in an outdoor side unit in operation is redressed. For example, when surplus refrigerant exists in an outdoor side unit, the refrigerant flow is so controlled that the surplus refrigerant is pushed out (flow out) into an outdoor side unit in non-operation. In addition, the output of the air-conditioning apparatus is smoothly variable (controllable) in accordance with an air-conditioning load over the whole air-conditioning load range from the minimum (zero) load to the maximum load.

Abstract: A multiroom air conditioning apparatus includes an outdoor side unit having a compressor and an outdoor heat exchanger, and a plurality of room units having an indoor heat exchanger. A high-pressure gas pipe and a low-pressure gas pipe, connected to the compressor, are branched so that a high-side branch pipe and a low-side branch pipe are connected to the outdoor heat exchanger via outside valves. A liquid pipe through which a refrigerant passes from the high-pressure gas pipe is connected to the outdoor heat exchanger, and branched to provide liquid pipes. The indoor heat exchanger is connected to the branched liquid pipes via expansion device and to the high-side branch pipe and the low-side branch pipe via inside valves. By controlling the outside and inside valves, a selected room unit or units can be cooled or heated.