Indian Journal of Science and Technology

Abstract

This paper analyzes the performance of jute fiber ropes that are used in the form of rope bank as wetted media in evaporative coolers. Widely spaced and compact arrangements of rope bank are taken into consideration. An ambient condition of 39.9°C and 32.8% RH is selected on the basis of weather data of Bhopal (2008) India particularly of weather in summer season. For the purpose of this study, the surface temperature of ropes is assumed as WBT of incoming air and theory of simultaneous heat and mass transfer is applied. Saturation efficiency, outlet temperature of air and cooling capacity are calculated for air mass flow rate of 0.9 kg/s to 0.3 kg/s. The saturation efficiency varies between 57% and 73% for widely spaced bank and between 74% and 87% for compact bank. Outlet temperature of air is determined on the basis of empirical correlation and is found to be in the range of 31.7°C-29.4°C and 29.4°C-27.4°C for widely spaced bank and compact bank respectively. The cooling capacity varies from 11243 kJ/h-26381 kJ/h and from 13384 kJ/h-33852 kJ/h for widely spaced bank and compact bank respectively. Fan power increases from 4.7 W-104.2 W and from 16.4 W-323.9 W for widely spaced and compact arrangement respectively. Variation of these parameters with mass flow of air is shown. It is seen that compact arrangement of ropes gives better performance although at the cost of high power consumption.
Keywords: Evaporative cooler, saturation efficiency, jute fiber, rope bank.