Patent ID: 8707716

Claim:
A method of defrosting a heat exchanger while the heat exchanger continues to cool air passing through the heat exchanger, the heat exchanger including a plurality of liquid passages for carrying cold liquid between an inlet and an outlet, and further including air passages in thermal communication with the liquid passages for cooling air passing through the air passages, the method comprising the steps of: introducing, using an injector, warmer liquid in liquid phase to a first selected section of the plurality of liquid passages while continuing to provide cold liquid in liquid phase to the liquid passages, the warmer liquid being introduced at a higher pressure than the cold liquid; maintaining the warmer liquid in liquid phase while passing through the liquid passages; pushing the air through the air passages using a fan driven by a motor; re-circulating the warmer liquid from the outlet to the injector using a pump driven by the motor; and selectively activating the pump using a clutch coupled to the motor.