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Recommended by O. O. Fasina and W. He and S. S. Kalligeros
Department of Farm Power and Machinery, College of Agricultural Engineering and Post Harvest Technology, Central Agricultural University, Ranipool, Gangtok, Sikkim 737135, India
Received 7 April 2012; Accepted 30 July 2012
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
1. Introduction
The sun is the source of all energy sources whether it is conventional energy sources or nonconventional energy sources. The sun provides us heat and light energy free of cost, which ultimately provides us energy and sensation of sight. Solar energy is the most readily available source of energy [1]. It does not belong to anybody and is, therefore, free. It is also the most important nonconventional sources of energy because it is nonpolluting and, therefore, helps in lessening the greenhouse effect [2]. Solar energy is one of the most promising renewable energy sources in the world compared to nonrenewable sources for the purpose of drying of agriculture and industrial products [3]. The concept of a dryer powered by solar energy is becoming increasingly feasible because of the gradual reduction in price of solar collectors coupled with the increasing concern about atmospheric pollution caused by conventional fossil fuels used for drying crops.
The solar dryer is a device which uses solar energy for drying. There are several processes by which heat can be transferred to a substance like conduction, convention, and radiation. Open sun drying is one of the oldest techniques employed for processing agricultural and food products. Considerable savings can be made with this type of drying since the source of energy is free and sustainable. However, this method of drying is extremely weather dependent and has the problems of contamination, infestation, microbial attacks and so forth, thus affecting the product quality. Additionally, the drying time required for a given commodity can be quite long and results in postharvest losses [4].
Solar dryer is an improved form of sun drying in which drying is accomplished in a closed structure under relatively controlled conditions utilizing the thermal energy of sun. Various types of solar dryers have been developed as an...