Describes a multi-system air conditioner with a new control method. The system comprises two indoor units and one outdoor unit. Its capacity responds to the load of each room by using an inverter-aided compressor and electronic expansion control valves that can automatically control the refrigerant flow for each indoor unit. States the control method for the refrigerant flow has been established by preliminary tests and experimental equations. The control system, which has a microprocessor with an original programme, leads simplification of the piping for the equipment and a reduction in piping cost. Notes that increased thermal comfort in each room has been verified by various experiments.

KEYWORDS: Air conditioning, controls, Japan, domestic, housing, thermal comfort, designing, experiment