Air conditioning apparatus

摘要

An air-conditioning system with a refrigerant circulation circuit, which has improved control precision for maintaining a compartment temperature and improved response characteristics. The refrigerant circulation circuit includes a variable displacement type compressor, the discharge capacity of which is controlled by a control valve. The control valve CV detects a differential pressure DELTA t between two pressure monitoring points in the refrigerant circulation circuit as an index for estimating the refrigerant discharge capacity of the variable displacement type compressor CM and performs feedback control of the discharge capacity of the compressor such that the differential pressure converges to a set differential pressure. A controller 70 determines or recomputes the set differential pressure based on information from a mode switching unit or an air-flow-rate switch and instructs the control valve to change the set differential pressure accordingly. The switch information from the mode switching unit or the air-flow-rate switch signals the controller 70 of a sudden change in the cooling load before the occurrence of the change or at the same time as the change occurs. <IMAGE>