Water flow control for air-conditioner using inverter-controlled induction motor drives

Since induction motors are widely used for water flow control of air-conditioning system, it is possible to apply inverter-controlled induction motor drives to achieve variable-water-volume (VWV) control instead of using conventional on-off control. The objective of this paper is to investigate the applications of inverter-controlled induction motor drives to the variable-water-volume control for the circulated cooling water pump of air-conditioners such that the flow rate of cooling water varies with load conditions and thereby increasing the efficiency of the system. Experimental results derived from the packaged air-conditioning units with 10 hp circulated cooling water pump demonstrate that significant amount of power saving can be achieved, confirming the proposed idea.