International Journal of Advanced Engineering Research and Science (IJAERS)
Vol-3, Issue-2 , Feb- 2016] ISSN: 2349-6495
Fabrication of Direct Evaporative Cooler and its Performance Analysis for Different Materials In Hot and Dry Climates Utkarsh Tripathi1, Dr. R.M.Sarviya2, Veeresh Fuskele3 1Department of Mechanical Engineering, MANIT, Bhopal, India 2Professor & Dean S/W, Department of Mechanical Engineering, MANIT, Bhopal, India 3Department of Mechanical Engineering, MANIT, Bhopal, India Abstract— This paper studies the performance analysis of different evaporative pad materials such as Charcoal, Activated Charcoal, Sponge of Sponge Guard ( Gilki in Hindi), brick bats and a combination of Wood Wool and Charcoal has been done in a specially design and fabricated evaporative cooling system. The objective is to analyse cooling effectiveness and cooling capacity at different velocities of air. Indore – MP and nearby places where temperature is in the range of 39 ◦C to 42 ◦C in summer days with relative humidity 22% to 29 %, in this scenario evaporative cooling is a good option. This analysis has been done on a special evaporative cooler maintains cool interior temperature for food preservation purpose. While these devices are not typically capable of maintaining temperatures of 2-3 degrees Celsius, they can be significantly cooler than ambient temperature. An evaporative cooler uses the principal of evaporative cooling to maintain a cool interior temperature for refrigeration and food preservation. The device is constructed from an open timber frame with evaporative pad material filled sides, which is kept continually moist. As warm, dry air flows through the moist material, water is evaporated into the air and it is cooled. Keywords—Evaporative Cooling, Direct and Indirect Evaporative Cooling, Cooling Effectiveness and Cooling Capacity, Activated charcoal I. INTRODUCTION 1.1 Evaporative Cooling: The principle underlying evaporative cooling is the fact that water must have heat applied to it to change from a liquid to a vapor. During evaporation, this heat is given to the water from dry air in the form of sensible heat when it comes in contact with water. Water takes this heat in the form of latent heat to convert its phase. 1.1.1 Direct Evaporative Cooling: In direct evaporative cooling the air to be cooled comes in direct contact with water. In such a process air gets humidified. www.ijaers.com
1.1.2 Indirect Evaporative Cooling: In indirect evaporative cooling, the air to be cooled does not come in direct contact with water. Instead, it is in indirect contact with a surface that is maintained at lower temperature with flow of water. In such a process its absolute humidity is not affected. 1.2 Activated charcoal It is a powerful adsorbent known. It is basically a solid material consisting mainly of pure carbon. A characteristic feature is its porous structure and the resulting immense surface area which may be large as 1500 sq m / gm. The surface area of Charcoal in present study is 200 sq m / gm. Activated Charcoal works on the principle of adsorption. Adsorption is an interfacial process involving the collection of gaseous or solute components on the surface of adsorbent solids. This phenomenon is associated with physical attractive forces that bind gaseous and solute molecules commonly known as Vander–wall forces. Activated Charcoal for Evaporative cooling-
Fig. 1: Pore structure of Activated Charcoal The adsorption power and rate is determined by the kind of activated charcoal, the particle size, the pore size and its distribution. Pore size and its distribution: When the carbon is activated it leads to opening of various pores in its structure. The pores with diameter exceeding 500 A° are called macro pores or the transport pores. These pores are larger pores and are not responsible for adsorption directly but they act as wide paths through which organic molecules penetrates. Thus they transport the adsorbent to the smallest adsorption pore site. Pores with diameter below 50 A° are called micro pores or adsorption pores. These are the finest pores, which are located inside the carbon particle where the adsorption actually takes place. Page | 6