Multi-type air-conditioning system with fast hot starting for heating

Abstract

An outdoor unit includes at least a variable-capacity compressor and an outdoor heat exchanger coupled thereto. Each of a plurality of indoor units includes at least an indoor heat exchanger and a section for outputting required capacity data. A distribution unit parallel-couples the plurality of indoor units to the outdoor unit so as to constitute a plurality of refrigeration cycles for at least heating operations. The distribution unit includes a plurality of refrigerant flow control valves for the respective refrigeration cycles. A first control section provides flow rate control commands to the refrigerant flow rate control valves, in accordance with the required capacity data, and controls an operating frequency to change a capacity of the variable-capacity compressor in accordance with sum data of the required capacity data. A second control section performs a frequency increasing control to increase the operating frequency of the variable-capacity compressor to a predetermined value higher than a value corresponding to the required capacity data when the heating operation is started. A third control section cancels the frequency increasing control of the second control section at a predetermined period of time elapse after the second control section causes the refrigeration cycles to start heating operations.