Dynamic simulation and thermoeconomic analysis of a novel indirect hybrid solar dryer

Abstract

Indirect solar dryers represent a clean and sustainable solution for drying foods, fruits, and vegetables. In this research, the performance of a novel indirect hybrid solar dryer has been investigated numerically on apple slices using TRNSYS software. The solar dryer consists of a flat plate solar collector, a vacuum tube solar collector, a cross-flow heat exchanger, an auxiliary heater, and a drying chamber. With the assumption that there is no access to fresh fruits and vegetables in winter, the simulation was carried out in three days on April 15, July 15, and October 15 (from 8 a.m. to 5 p.m.) as representatives of spring, summer and autumn, respectively. The humidity content of apple slices reduced from 86 % to 11 % in about 270 min at 70 °C. The minimum power received from the auxiliary heater was on July 15 with 1497 W, which was about 1.5 h without needing a backup heater. (from 11:30 a.m. to 1 p.m.). The maximum thermal efficiency of the drying system was obtained on July 15 at about 60 % for the flat plate collector, 78 % for the vacuity tube collector, and 25 % for the drying chamber. Also, the return on capital in Iran, USA, UAE, and Turkey was equal to 1.49, 0.74, 0.95 and 1.35, respectively.