J. King Saud Univ., Vol. 25, Arch. & Planning (1), pp. 1-12, Riyadh (2013/1434H.) 1 Evaporative Cooler: Self Salt Clean Mohammed Ali Bahobail Department of Architecture and Building Sciences, College of Architecture and Planning, King Saud University (Received 28/01/1432H.; accepted for publication 20/07/1432H.) Abstract. Evaporative coolers are popular in the dry climate region as an energy efficient means for space cooling. It consists of a large metal box with a big fan and three water wetted pad doors. The wetted pads are usually made of cedar shavings or cellulose, which kept damp by a water circulation pump. The fan drags the hot and dry outside air through the wetted pads cooling the air due to evaporate water molecules from the pads. The fan then blows the cooled air through an outlet vent. Evaporative coolers are relatively economical, less expensive to install and to operate. They are consuming less electricity than a refrigerated unit, and they do not need an expert to maintain. In addition, evaporative coolers provide the building with a fresh humid air. However, evaporative coolers have some disadvantages; one of them is the deposited salt. Water usually has a high percentage of mineral. The evaporative mechanism will leave mineral deposits on the pads and interior of the cooler. This cumulative mineral will close the porous of the wetted pads and damage them and will participate to corrosion of the cooler frame. This study aims to develop the evaporative cooler efficiency by utilizing solar water still. The main objective of this proposal technique is to minimize the quantity of the cumulative salt by removing part of it. Introduction Evaporative coolers (also called swamp coolers, desert coolers, and wet air coolers) are devices that cool air through the evaporation of water. They are especially well suited for hot dry region. The amount of heat transfer depends on the evaporation rate, which depends on the humidity of the air and its temperature. The normal design, therefore, is a metal box with three vented sides. Each side has a removable wetted pad door. Usually, evaporative cooler pads made of excelsior (wood wool) inside a bag of net. Recently, more modern materials, such as plastics and melamine paper, are starting to be used as cooler- pad media. The thickness of the wetted pad plays a very significant role in cooling efficiency, the more pad thickness the longer air contact. The cooled air is delivered by a centrifugal fan which is connected to an electric motor through pulleys and belt. Water is circulated by a small water pump to wet the evaporative cooling pads (Fig. 1). The evaporative coolers have several advantages; they save cooling energy comparing to a refrigerated systems. The fan and water pump are the only parts consuming power vs. compressors, pumps, and blowers in the other systems. They are environmentally friendly; provide the building with a fresh humid air, and low installation and operation cost. The installation cost is about half that of central refrigerated air conditioning (Krigger and Dorsi, 2004). In addition, they do not need a specialist for maintenance. The only two electrical parts are an electric fan motor and a small water pump, which can be repaired or changed by the home owner at low cost. These advantages made those techniques to be commonly used in Gulf countries. However, evaporative cooling consumes a huge amount of water to wet the pads. The evaporative mechanism will leave salt deposits on the pads and interior surfaces of the cooler (Figs. 2 and 3). This cumulative salt will block the air flow by closing the porous of the wetted pads and damage them. Besides that, this salt will contribute to corrosion of the cooler body.