Journal of Environmental Research And Development Vol. 4 No. 2, October-December 2009 465 DESIGN AND PERFORMANCE ANALYSIS OF LOW COST SOLAR STILL USING TRANSPARENT LDPE COVER R. Jayaprakash*, K. Perumal, T. Arunkuma 1 , Sanjay Kumar 2 and B. Selvakumar 3 1. Solar Energy Laboratory, Department of Physics, Sri Ramakrishna Mission Vidyalaya, College of Arts and Science, Coimbatore-641020, Tamilnadu, (INDIA). 2. Department of Physics, BR Ambedkar Bihar University, Muzaffarpur-842001, Bihar, (INDIA). 3. Department of Physics, RVS Engineering College, Coimbatore, Tamilnadu, (INDIA) Received July 24, 2009 Accepted December 02, 2009 ABSTRACT Solar still is a device which allows to obtain fresh water from brackish water. This paper reports about the newly designed spherical solar still under climatic conditions and operational parameters in Coimbatore (11° N latitude), India. The performance of spherical solar still with two different thicknesses of low density polyethylene (LDPE) cover is analyzed. The spherical solar still was covered by low density polyethylene cover (LDPE) of thickness 0.176 mm and 0.107 mm respectively. The water temperature, air temperature, ambient temperatures are recorded at the regular intervals of time. The inside and outside of the cover temperatures are noted with solar radiation. The efficiency of the spherical solar still is analyzed for two thicknesses top cover. The internal heat transfer mode and external heat transfer mode are calculated. The hourly output yield per m 2 of the still is calculated. This type of solar still is promoted for an easy utilization for rural people. The cost of designing of the spherical solar still is very much economical. The salient feature of this still is simple, low thermal capacity, lightweight and ease to operation. Key Words : Spherical solar still, LDPE, Efficiency, Heat transfer, Thermal capacity. INTRODUCTION There are many methods of converting brackish water into potable water. Among the processes which are now commercially employed, the distillation of brackish or seawaters is considered to be one of the simplest and widely adopted technique for converting salted water to fresh water. In this method, the water is evaporated using thermal energy and the resulting steam is collected and condensed as final product. Several research results were published where heat transfer coefficients are calculated theoretically for various operating conditions. Heat flows are found generally by assuming that transfer mechanisms such as convection and mass diffusion take place simultaneously, and the total is calculated by * Author for correspondence