Abstract: A cooling system of the type having a cooler section. The conventional cooling tower is disconnected and replaced by a cooling loop connected to a water source such as a municipal water supply, irrigation system or gray water system which cools the condenser portion of the cooler. Isolating heat exchangers may be interposed in the cooling loop to avoid contamination. A by-pass system and tempering valve maintain the water supply at a predetermined temperature. Heat may be extracted from the water return and utilized at a remote location as for heating a part of a building while another part is being cooled.