Abstract
•Basic parameters were obtained by the steady-state experiments.•Experimental efficiency of the mixed solar dryer.•Experimental efficiency of the solar collector.
This paper presents an experiment and an examination of the performance of a mixed solar dryer with forced convection, which has been used to dry tomatoes. The studied system is composed of a photovoltaic-thermal air collector (PV/T) and drying room. Actually, the air flux enters in the aluminium tubular canals located under the PV panel and spreads simultaneously into an upper gap. Consequently, it provides heat exchange in both faces of the panel PV which helps to cool the photovoltaic cells and to carry the thermal energy to the drying room. What make this prototype important and original is that it provides an economic gain for farmers who previously used natural drying techniques. It grants them the chance to conserve the dried tomatoes for longer periods and to reduce the loss of crops. Furthermore, it provides more electrical energy supplies for the rural areas. Tomatoes were divided into two trays and dried with the forced convection mixed solar dryer. After that, a comparison was established with a naturally dried sample. Using the realized prototype, product moisture content dropped from 91.94 (%) to 22.32 (%) for tray 1 and to 28.9 (%) for tray 2, by against it dropped only to 30.15 (%) for open sun dryer. It is noted that the drying temperature is improved and the quality is enhanced. The experimental tests are carried out at the Laboratory of Electromechanical Systems in the National Engineering School of Sfax in Tunisia during September 2015.