Conventional and Corrected Performance-Rating Parameters of Direct Evaporative Air Coolers

摘要

The objective of this paper is to calculate conventional and proposed performance- rating parameters for direct evaporative coolers from published literature so as to reflect the real characteristics of the cooler. Weather data were collected during the summer months at Bhopal, India and the most frequently occurring ambient condition of 39.9℃ average maximum dry bulb temperature and 32.8% average relative humidity is selected. The velocity of air flowing through the rigid cellulose media was considered between 0.75 m/s and 2.25 m/s. Saturating efficiency which ranges between 72.4% and 79.9% and conventional cooling capacity which ranges 11978 kJ/h and 32568 are calculated using established procedure. Fan and make-up water heat gain correction gives the Corrected Net Cooling Capacity, the value of which ranges between 11494 kJ/h and 31195 kJ/h. After correcting for local weather conditions, the value of Unit Cooling Capacity is obtained to be between 803 kJ/h℃ and 2180 kJ/h℃. Power consumption is considered by calculating Evaporative Energy Efficiency Ratio which varies between 36 and 47. After correcting for local weather conditions, it lies between 2.54 and 3.3 Performance of the cooler is better reflected by Corrected Net Cooling Capacity and Evaporative Energy Efficiency Ratio than simple volumetric capacity whereas comparison of different coolers operating under different climatic conditions is facilitated by Unit Cooling Capacity and Unit Evaporative Energy Efficiency Ratio.