Impact of Water Use for Air Conditioning on Chicago's Water System

Abstract

ПЩЕ Chicago water supply system is JL now confronted with economic and operating problems of a most serious nature because of the wasteful use of water brought about by the amazingly rapid increase in installations of nonconserved water-using air-conditioning equipment for industrial, commercial, and domestic purposes. Because of the present low water rates and the short air-conditioning season, the revenue derived from the sale of water for this purpose cannot begin to cover the annual fixed charges for construction of the large standby plant capacity needed to supply the high water demands of air-conditioning water usage. In general, air-conditioning installations may be divided into three categories : 1. Air-cooled units which use no water. The widely used window units are of this type. Capacities are usually e to 5 tons. This type presents no problem to water supply system. 2. Water-cooled units equipped for conservation. These units use cooling towers or evaporative condensers which recirculate the cooling water and require makeup water at a rate of no greater than 0.15 gpm per ton of air conditioning. Such water use usually does not place undue strain on an existing water system. 3. Water-cooled units of the nonconserved type. Cooling water is passed through these units at a maximum rate of 1.5 to 2 gpm per ton of air conditioning and is then discarded, after one passage through the equipment. It is this uneconomical high-rate water use which causes serious water supply difficulties in the Chicago water system.