A Comparison of Hot Dry and Transitional Season Solar Drying with a Modified V-Corrugated Solar Air Heater

Abstract

The thermal performance of solar air heaters can be significantly enhanced by changing the shape of the absorber plate, which increases heat transfer surface area and airflow turbulence. This study investigates the seasonal drying performance of a modified V-corrugated solar air heater that uses natural convection for tomato drying in Kano, Nigeria. Experiments were carried out throughout the transitional season (October-November 2019) and the hot dry season (April-May 2021), using ASHRAE 93-2003 testing procedures. The system includes a V-corrugated aluminium absorber panel, an enclosed drying chamber with three trays, and a chimney to improve buoyancy-driven airflow. The results revealed a maximum drying efficiency of 54.66% during the transitional season and shorter drying periods of 10-12 hours during the hot dry season, compared to 16-22 hours in the transitional months. The moisture level fell from 95.65% to 10% across all trials. Higher sun irradiance, decreased relative humidity, and elevated ambient temperatures during the hot dry season considerably improved the drying performance. The redesigned absorber design improved heat transfer and lowered drying time by 70-85% compared to open-sun drying. The technology provides an economical and sustainable post-harvest preservation solution for rural and off-grid areas.