A review on performance evaluation of solar dryer and its material for drying agricultural products

Abstract

The drying process is generally carried out by burning wood and fossil fuels. However, this method is expensive and may damage the environment which has an adverse impact on climate. The world is facing the problem of shortage of fossil fuels. Some researchers did historical work on design and development of solar technology which is faster, more efficient, and hygienic and better quality of the product. Several solar dryers reviewed and enlisted the performance of dryers as per application. This paper gives an idea about the recent development in solar dryers. Some solar dryers are equipped with thermal storage to enhance the efficiency and drying rate in off-sunshine hours. To overcome the sunshine irregularity, some solar dryers have come up with solar thermal reservoirs. A comprehensive review on different dryers according to the product has been carried out, which helps in development and redesign of the solar dryer. From this paper, an idea regarding products drying likes chili, turmeric, peanut, grapes, copra and fish are presented. Which type of dryer is suitable and what kind of improvement could be possible in the future is obtained. For performance evaluation of the solar dryer, researchers used parameters like moisture reduction, moisture removal rate and different efficiencies. Solar dryer did not receive commercial utility because of high initial investment, long payback period and intermittent application. The study shows that the solar dryer not only saves fossil fuel for drying but also adds great worth to improve the product quality in terms of taste and color. It also doesn’t have any harmful effect on the environment. Solar dryer is therefore ideal to use for preservation of food in rural areas. This study may help farmers and new researchers for the design new type of solar dryer for products.