Construction and Evaluation of a Dr ying Chamber Powered by Parabolic Trough Solar Concentrator for Drying of Agricultural and Other Materials

Abstract

This work reports a design and construction of a drying chamber powered by parabolic trough solar concentrator. The construc ted drying chamber is made of thin aluminum sheet material with two compartments; one is fo r installation of standby electrica l heaters and the other is for material pallet. The chamber is powered by a para bolic trough solar concen trator with aperture area of 5 m 2 . An electrical heater backup was employed to maintain the temperature inside the chamber at a given constant temperature when solar energy is not sufficient. The maximum variation of the temperature insi de the chamber along the length of the material pallet was found to be 8 °C when the chamber is powered by sola r concentrator. This va riation was 16 °C when the chamber is powered by electric heaters. Temper ature variation across the vertical direction is almost constant when the chamber is empty and a 10 % drop in temperature was observed over the material pallet relative to the other areas. The drying characteristics of samples of cabbage, boiled rice, scraped coconut, dry le aves and grass for different te mperatures obtained using the drying chamber are found to be fitted well with the page mode l and the corresponding drying constants at 80 °C are found to be 0.0197, 0.0139, 0.0319, 0.0296, 0.0564 respectively.