Energy and exergo-environmental (3E) analysis of wheat seeds drying using indirect solar dryer

Food insecurity is becoming a big problem due to the continuous increase in the population, for which there is a requirement of effective drying method for the storage of agricultural items which can solve this problem at global level. Hence, the present study deals with the evaluation of energy, exergy, and environmental parameters of low-cost indirect solar dryer with paraffin wax as energy storage material in rural areas for drying of wheat seeds to check its thermodynamic as well as environmental feasibility. The wheat seeds were dried in solar dryer from initial moisture of 20.2% in 6 h to achieve recommended moisture content which took lesser drying time as compared to open sun drying. The maximum value of collector exergy efficiency, exergy efficiency of drying chamber and pick-up efficiency are 1.5%, 72.62%, and 30.4% respectively. Environmental impacts assessment has revealed that the energy payback, CO₂ mitigation, CO₂ emission per year and carbon credit earned (at $80 per carbon credit) with present system are 1.35 years, 6.67 tons, 7.32 kg and $533.7, respectively considering the lifetime of solar dryer as 25 years. The performed study shows that the indirect solar dryer with paraffin wax is suitable for the households of rural areas with enhanced performance, lesser waste, sustainable, and lesser adverse effect on environment. This system can also be preferred for drying of other agricultural crops for a particular household.