Experimental study of a natural convection indirect solar dryer

Abstract

This paper investigates the effectiveness of an indirect solar dryer (ISD) specifically designed for the geographical and climatic conditions of Meknes (Morocco). The constructed ISD system incorporates a solar air collector (SAC) inclined at 34° to the ground, reaching a maximum outlet temperature of 58 °C. During the drying process, banana slices experienced a substantial reduction in mass, decreasing from 549.76 g to 138.41 g. The calculated mean efficiency of both the SAC and the dryer stood at 23.37 % and 18.8 %, respectively. In terms of moisture removal, ISD outperformed open solar drying (OSD), achieving a substantial moisture reduction of 74.83 %, whereas OSD yielded a reduction of 39.08 %. The process of drying resulted in a decrease in the moisture content (MC) of banana slices from an initial value of 3.5771 kg/kg (db) to a final value of MC varied depending on the tray used for drying, with values of 0.0397, 0.1292, 0.1745, and 0.2597 kg/kg (db) recorded for trays 1, 2, 3, and 4, respectively. By focusing on the development and evaluation of an ISD system optimized for the local conditions, this research contributes valuable insights into efficient and sustainable food drying.

Keywords

• Indirect solar dryer
• Solar drying
• Natural convection
• Solar air collector
• Banana drying
• Collector efficiency