Innovative experimental investigation of a solar dryer with an evacuated tube solar air heater and various thermal energy storage techniques

Solar drying systems are energy-efficient, and their performance can be improved with integrated thermal storage materials to stabilize the intermittent radiation input from the sun. To that effect, this paper attempts to make an appraisal of three different types of solar dryers: an evacuated tube air solar heater-based indirect solar dryer, a solar dryer integrated with latent thermal storage, and a solar dryer coupled with latent heat thermal storage and granite pieces. It aims at finding the impact of those changes on drying rates, thermal efficiency, and general system performance. The results reveal that Case 1 achieved an average moisture removal rate of 0.072 kg/h, a final mass ratio of 0.62, a drying efficiency of 9.59 %, and an overall efficiency of 4.66 %. Case 2, with latent heat storage, followed by a moisture removal rate of 0.091 kg/h, a mass ratio of 0.54, a drying efficiency of 11.27 %, and an overall efficiency of 5.89 %. In comparison, Case 3, using latent heat storage combined with granite pieces achieved the highest performance, with a moisture removal rate of 0.101 kg/h, a mass ratio of 0.49, a drying efficiency of 13.67 %, and an overall efficiency of 6.39 %.