An environmental and economic evaluation of solar photovoltaic thermal dryer

The photovoltaic thermal (PVT)-based solar dryer is advantageous in terms of energy-saving ability, efficiency, self-sufficient design, and ability to work without any additional electrical energy requirement. However, there is a requirement for a comprehensive analysis of the energy, exergy, and environ-economic parameters for developing an efficient and sustainable PVT solar dryer. In this study, a PVT-based indirect mode solar dryer with forced convection has been fabricated and investigated in the environmental conditions of North-East India (Silchar latitude of 24.83 degrees). Experiments have been performed to compare the drying characteristics of tomatoes with quality analysis under the open sun and solar drying conditions. A new mathematical drying model is proposed to predict the drying characteristics of tomatoes under both modes of drying. The average PVT dryer efficiency is 34.98%, higher than some of the published works of indirect mode solar dryers conducted under similar experimental conditions. The calculated values of drying effectiveness, collector efficiency factor, coefficient of performance, and heat utilization factor are 1.12-1.58, 0.011-0.029, 0.71, and 0.29, respectively. Furthermore, CO2 emission, CO2 mitigation and carbon credit earned parameters are evaluated for 10, 20, and 30 years of system life.