Energy and exergy analysis of solar drying process of Mint

Renewable energy in food industry and particularly in drying process is growing and mainly in developing countries. Solar energy is often used by direct products exposure through a glass or to heat drying air through a solar collector. However, the random and intermittent nature of solar radiation leads to use conventional energy sources as supplement. Hence, optimization and design tend to reduce the drying time of products for minimum possible energy use. These cases are often preceded by rigorous energy and exergy drying process analysis. That is the aim of our work in this paper. The used dryer is an indirect type, passive, without extra energy and discontinuously operating. It is composed of a solar air heater and a drying room. The experiment took place at Bouzareah on the heights of Algiers in the summer season. The choice of mint is because its abundance and its wide use in Algeria. Using the first and second principles of thermodynamics, we could estimate useful energy received by the heater and that really used during drying. Energy analysis has allowed us to quantify the solar energy received by solar heater and available for drying. Exergy analysis has allowed us to estimate the energy losses during the drying process.