Comparative Analysis of Traditional and Solar Drying Techniques for Red Chilli

Author(s) : Shakeel Hussain Chattha, Shakeel Ahmed Soomro, Ali Hassan Rahu, Bakhtawar Wagan, Zaheer Ahmed Khan, Abeera Moin and Angelo Maria Giuffrè

Digital object identifier:

https://doi.org/10.52587/JAF060109

Abstract:

This study compared the performance of direct solar dryer, indirect solar dryer, and open-sun drying methods for red chilli. The solar dryers consisted of collectors, drying chambers, and airflow systems, while open-sun drying involved spreading chilies on polyethylene sheets under direct sunlight. Drying occurred from 9:00 am to 3:00 pm until the desired moisture content was reached. Average ambient conditions included a temperature of 31.04°C, relative humidity of 63.68%, air velocity of 3.45 m/s, and solar radiation of 365 W/m². The highest temperature was recorded in the direct solar dryer (57.6°C), followed by the indirect solar dryer (55.4°C) and open-sun drying (38.1°C). The direct solar dryer had the lowest relative humidity (41.2%) compared to the indirect solar dryer (43.1%) and open-sun drying (53.2%). Solar radiation was lowest in the indirect solar dryer (230 W/m²). Drying time was 32 hours for the direct solar dryer, 36 hours for the indirect solar dryer, and 50 hours for open-sun drying. The highest drying rate (6.1 g/hr) was observed in the direct solar dryer, followed by the indirect solar dryer (5.9 g/hr) and open-sun drying (2.4 g/hr). The direct solar dryer proved to be the fastest and most efficient for drying red chili while maintaining quality.