IJRME - International Journal of Research in Mechanical Engineering ISSN: 2349-3860 EXPERIMENTAL INVESTIGATION OF SOLAR FLAT PLATE COLLECTOR FOR DRYING CHILLIES M.S.Heaven Dani 1 | S.Maharajan 2 | S.Praveen 3 | S.Ramesh 4 | A.Saravanan 5 1 (Mechanical Engineering, Velammal Institute of Technology, Chennai, India, heavendani@gmail.com) 2 (Mechanical Engineering, Velammal Institute of Technology, Chennai, India, mahakalam95@gmail.com) 3 (Mechanical Engineering, Velammal Institute of Technology, Chennai, India, praveensaravanan1995@gmail.com) 4 (Mechanical Engineering, Velammal Institute of Technology, Chennai, India,rameshsadasivamk@gmail.com) 5 (Mechanical Engineering, Velammal Institute of Technology, Chennai, India, saravanaanandharaj@gmail.com) ___________________________________________________________________________________________________ Abstract—This research includes the design and manufacture of indirect forced convection solar dryer and its performance test on Chillies under the metrological conditions of Chennai, India. Solar dryer consists of Solar Collector and Drying Chamber section with three trays. The drying test was conducted with the blower of blowing capacity 2.5m3/min. The maximum air temperature achieved in the dryer was 〖72〗^0 c.The dryer was loaded with 100grams of chillies having an initial moisture content of 75% and the final desired moisture content of 14% was achieved within 7hours.This prototype dryer was designed and constructed to have a maximum collector area of 0.07m2 .This solar dryer have been used in experimental drying tests under various loading conditions. Keywords— Solar dryer; Chillies drying;Indirect forced convection; Drying Chamber. ______________________________________________________________________________________________________________ 1. INTRODUCTION The traditional method of drying known as ‘sun drying’ involves simply laying the product in the sun. Major disadvantage of this method is contamination of the product by dust, destruction by insects and microorganism, and pecking by birds. Furthermore, some percentage will usually be lost or damaged during handling. It is a labor intensive, nutrients loss occurs, such as vitamin A, and is time consuming. Lastly, the method totally depends on good weather conditions. The major advantage in the energy requirement for this open sun drying process is that the solar and wind energy is readily available freely in nature. Hence, the capital requirement is marginal, making it the viable method of drying agriculture product even commercial scale especially in developing country.The safer alternative to open sun drying is drying in a solar dryer. This is a more efficient method of drying which produces better quality products, but in this case, initial investments are required. A. Solar dryers A Solar dryer is an enclosed unit to keep the food safe from damage from birds, insects, microorganism, pilferage and unexpected rainfall. The product is dried using solar thermal energy in a cleaner and healthier fashion. Basically, there are four types of solar dryer. Direct Solar Dryer In these dryers, the material to be dried is placed in a transparent enclosure of glass or transparent plastic. The sun heats the material to be dried, and heat also builds up within the enclosure due to ‘greenhouse effect’. The drier chamber is usually painted black to absorb the maximum amount of heat. Indirect Solar Dryer In these dryers, the sun does not act directly on the material to be dried thus making them useful in the preparation of those crops whose vitamin content can be destroyed by sunlight. The products are dried by hot air heated elsewhere by the sun. Mixed Mode Dryer In these dryers, the combined action of the solar radiation incident on the material to be dried and the air preheated in solar collector provides the heat required for the drying operation. Hybrid Solar Dryer In these dryers, although the sun is used to dry products, other technologies are also used to dry to cause air movement in the dryers. For example, fans powered by solar PV can be used in these types of dryers. The Drying Process The process of dehydration consists of removal of moisture from the product by heat usually in the presence of a controlled flow of air. Initially, the procedure to be dried is washed, peeled and prepared (if necessary), and placed on flat-bottomed trays that are placed into the dryer. The solar rays enter the cabinet through the cover material. Upon reaching the solar collector or the tray surface, they are converted into heat energy, raising the inside temperature. The heated product gives out water vapor and dries up. Gradually the heated moist air goes up and leaves the IJRME - International Journal of Research in Mechanical Engineering Volume: 03 Issue: 01 2016 www.researchscript.com 20