Executive Summary : | Due to wide diversity in climatic conditions in India, different varieties of plants and vegetables are grown across the country and some of them are elixirs of life due to their amazing health benefits. Food preservation is important because 1\3rd of the food globally produced is wasted due to lack of proper processing, preservation and storage methods. India has the 3rd population in the world and around 25 million people die every year due to chronic hunger. At the same time, India is an agriculturally predominated country that produces around 259 million metric tonnes of fruits and vegetables every year which is enough to meet the requirements of the whole population. In most of the food drying industries, convective drying is the most widely used method of preservation. There are many convective drying systems (CDS) have been developed by various researchers, but the major limitation of CDS is that it is a highly energy intensive process that consumes 20 - 30% of total industrial energy which in turn gives around 1 to 2 % of energy efficiency and corresponds to 90% of processing cost. In addition, it emits a huge amount of carbon dioxide into the atmosphere which causes many serious issues like global warming, acid rain, and stratospheric ozone depletion. The solution of the problem arising from the CDS can be resolved using solar drying method. The solar drying is becoming very popular nowadays because of the availability of enormous amount of free solar energy and it is environment friendly. But again, the solar drying system (SDS) has many limitations as the drying can be performed only during sunny days and there is non-uniform drying of food due to the variation in the intensity of the solar radiation across the day. The limitation of SDS is overcome by assisting the solar dryer by the CDS to make it hybrid drying system (HDS). The main advantage of hybrid drying system is that the efficiency will be increased by multiple times. In this project, an attempt will be made to developed a cost effective and environment friendly HDS by coupling of natural convection solar drying system with the PVT operated solar collector forced CDS. This HDS is further integrated with the wind tunnel type CDS operated through electricity for round the clock operations. The drying and shrinkage characteristics of the medicinal plants and vegetables are determined at different drying conditions. A digital imaging technique will be used to quantify the shrinkage and resulting deformation in terms of dimensional changes in the medicinal plants and vegetables. The hybrid drying system's thorough exergy-based performance study, as well as its economic and environmental analysis, will be determined. The performance of the HDS is determined by comparing it with the convective drying, solar drying with and without solar collector, and open sun drying method. The performance will be done based on energy and exergy analysis, and economic and environmental analysis. |