Performance Evaluation of Different Evaporative Cooling Pad Materials

Abstract

An evaporative air cooler is a device that cools air through evaporation of water. It is especially well suited for climates where the air is hot and dry. As the evaporative cooling is the simplest way of cooling the air, it can be convenient to install with less of the equipment. The efficiency of evaporative cooling systems is affected by many factors including surface area, thickness of pad, type of material used in the pad, size of perforations, flow rate of water for saturating pad, relative humidity of air passing through the pad. Evaporative pads are made from different materials such as metal, cement, wood, plastic, and glass. Manufacturing of commercial pads made of these materials are complicated and costly. Therefore, evaluating the locally available cheap materials for use as pads, particularly in rural agricultural areas is essential. Recently, manufacturers have been designing new pads made of cellulose paper to make evaporative cooling more useful and efficient in different applications including industrial and residential sectors, swine building, poultry, greenhouses, as well as storage. An exhaustive literature review was done in order to find out the results of the research work conducted so far in this area. It is found that if the suitable material is used it can enhance the cooling effect. Using the correlations available in literature for the heat and mass transfer between air and water in a direct evaporative cooler, cooling efficiency of pad made from cellulose paper and GLASSdek is investigated and compared for different pad thickness ranging from 50 mm to 195 mm. The pad cooling efficiency is also investigated and compared for the same materials for the different velocities varying from 1 m/s to 3 m/s. The predicted results can be used for the selection of the cooling pads based on the thickness and velocity of the frontal air. In the present work experimental performance investigation of evaporative cooling pad made of different material like cellulose paper, PVC material, Fabric strips, Cotton strips and Jute strips have been carried out. The cooling pads made from Cotton strips and Jute strips are newly prepared for experimental purpose where as others cooling pads are available. The performance of cooling pad for the different rpm of air blower and for the constant mass flow rate of water 900 lph and 1200 lph are investigated.