Eun-Chul Kang, Jin-Soo Kim, and Euy-Joon Lee, Korea Institute of Energy Research(KIER), 71-2 Jang-Dong Yusong-Gu, Daejeon 305-343, South Korea

M. Masaood Hashmi and I. A. Qazi, Pakistan Council of Renewable Energy Technologies (PCRET), Plot No. 25, Sector H-9, Islamabad, Pakistan

Solar Air Heating is a simple and inexpensive technology that results in reduced energy consumption and lower operating costs associated with fresh air ventilation requirements (Seidermann, 1997) in a building. This device, while drawing the fresh air from outside the building, preheats it by letting it pass through tiny holes in a dark — colored thermally conductive surface that has been heated absorbing by the thermal component of the sun’s radiation. Obviously, such devices are usually mounted on the side of a building that receives the most sunlight (e. g. the south wall, in the Northern hemisphere). Compared to other types of solar heat collectors, the unglazed perforated cladding is a cost effective, virtually maintenance free, room-heating solution. The well-known and commercially available solar air heating systems called the solar wall, has been the subject of several studies by Hollick (1994,1998), Kokko and McClenahan (1994), Gunnewiek (1996), and van Decker (2001). As indicated above, the basic physical system of the solar air heating collector is one where suction is applied to a heated perforated plate that is placed as a facade on the south facing external wall of a room. The outside air is drawn straight from ambient through the entire surface of the perforated blackened plate. The intimate heat transfer, between the plate and the sucked air, keeps the plate temperature low, minimizing the radiant loss (Gerald W. E and Van Decker). Such a system is usually subject to the natural buffeting and turbulence of the wind. The cooling effect of the wind would obviously depend, among other things, on the ambient temperature and the wind velocity. In order to quantify this effect and to develop a mathematical model for it we studied the efficiency of a system under the laboratory conditions.