Evaporative cooling is the basic of mostly all refrigeration technology that involve a phase change in refrigerant. The Evaporative technology is used in Hot and dry areas. In these areas it is more effective and cost efficient than the air conditioners. But in humid areas, Evaporative cooling does not bring thermal comfort. Thermal comfort is a state where our body feel good with respect to temperature of surrounding. Working principle Evaporative cooling: For Moist air: When hot and dry air pass through an evaporative pad (a wet pad, with same water quantity always during evaporative process), It take some water(wet vapor form) from pad and the heat require to evaporate water is taken from water itself. As latent heat is almost 100 times the sensible heat for water, So a small portion of water will evaporate, resulting in overall reduction of temperature of water and air leaving the air and water at wet bulb temperature of entering air. (refer to figure) ...