Numerical and Experimental Validation of Solar Tunnel Dryer for Drying Agricultural Products under Togo Climatic Conditions

Kokou Agbossou^1, , Tchamye T. E. Boroze¹, Komi Apélété Amou¹, Kossi Napo¹ and Andre D.L. Batako²

¹Laboratoire sur l’Energie Solaire, Département de physique, Faculté des Sciences, Université de Lomé, BP : 1515 Lomé, Togo

²Genaral Engineering Research Institute, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK

Cite this paper:
Kokou Agbossou, Tchamye T. E. Boroze, Komi Apélété Amou, Kossi Napo and Andre D.L. Batako. Numerical and Experimental Validation of Solar Tunnel Dryer for Drying Agricultural Products under Togo Climatic Conditions. International Journal of Physics. 2023; 11(6):274-282. doi: 10.12691/ijp-11-6-1

Abstract

This paper presents the mathematical modelling and experimental validation of a solar tunnel dryer Hoheinhem -Type for drying maize in Togo climatic conditions. All the experimental tests were done in Gape Kpodzi city (6°42’N latitude and1°21’W longitude), in South Togo, 88 km from Lomé, during the summer season. Solar dryers consist of an air collector, a drying chamber, and an air circulation system. Heated air in solar air collector was forced through the maizes by a blower. Yellow dent-type Maize was used for drying experiments. During the drying period, drying air temperature, relative humidity, airflow rates, solar radiation, and loss of mass were measured continuously at different levels of the dryer. The tunnel dryer is a metallic framed structure covered with a 200-µm ultraviolet stabilized plastic sheet. The dryer works on mixed-mode convection, and the maximum temperature attained during the experiment was 58.11 °C. The air temperature at the collector outlet ranges from 32°C to 68°C. The solar tunnel dyer Hoheimhem-Type dried the Maize from an initial moisture content of 35% (wb) to 13% (wb) in 15 solar hours under typical Togo climatic conditions. A system of partial differential equations describing heat and moisture transfer during the drying of Yellow Maize in this solar tunnel dryer was developed and the system of nonlinear partial differential equations obtained was solved numerically by the finite difference method. The mathematical modelling was programmed in Fortran PGI version 2008. The simulated results agreed well with experiential data for solar drying of maize. Some additional parametric studies are presented and is shown that this model can be used to provide the design data and to optimize this type of drier.

Keywords:
experimental style mathematical modeling solar tunnel dryer simulation solar drying of maize

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