A Pump Economizer for Evaporative Coolers

The water flow rate in the existing evaporative coolers used in India for domestic cooling (called “desert coolers” in the local markets) is much higher than what is required to keep the fibre pads wet. Therefore, a retrofit has been designed to lower the electrical energy consumption of the coolers. We report here on the design, performnace and economics of the proposed retrofit which can be very easily fitted to existing coolers. The cost of the retrofit, including installation charges, is about Rs. 95 (1988 rupees) or about US$ 6 (US$ 1 = Rs. 15.60), and the resulting annual electricity savings are about 25 kWh. Since space cooling contributes to the summertime peak electricity demand in large North Indian urban centres such as Delhi, the device appears very attractive for conserving electrical energy and peak urban electricity demand in summertime.