Performance analysis of solar and solar-infrared dryer of mint and apple slices using energy-exergy methodology

Abstract

In this study, double-pass solar air dryer (DPSAD) and infrared assisted double-pass solar air dryer (DPSAIRD) were designed and tested. The effects of using infrared energy have been experimentally investigated to ensure continuity in climatic conditions (cloudy, etc.) where solar energy is insufficient. Comparative experiments were carried out in the summer and autumn. Energy and exergy analysis, mass and heat transfer, performance coefficient, specific energy consumption, drying efficiency, energy efficiency and error bars have been used as criteria for evaluating thermal and structural performance of solar dryer and to see the effects of infrared energy on dried products (apple slices and mint leaves). The highest thermal efficiency of the collector was obtained as 83.56%. For DPSAIRD and DPSAD, exergy efficiency values were calculated as 49.17%, 59.07%, 59.06% and 69.35%, respectively. Energy efficiencies varied between 1.15% and 8.59% for DPSAIRD, 2.20% and 26.46% for DPSAD. Despite the low radiation values in autumn and the lower ambient temperature, it was found that the drying times are almost the same as in the summer months, thanks to the use of infrared energy. The IR lamp significantly increased energy consumption; however, in cases where the collector was insufficient, it supported both the collector and protected the products against deterioration. © 2019