Design development of photovoltaic-thermal (PVT) hybrid solar dryer

Abstract

A photovoltaic-thermal (PVT) hybrid solar dryer was designed and fabricated in such a way that it enabled the combined production of electric energy and thermal energy from the photovoltaic panel and flat plate collector. The dryer consists of a collector unit, drying chamber, DC fan, PV panel and PCM chamber for thermal storage. The PV module was provided at left side of solar collector to operate a DC fan for forced mode of operation. The dryer having a size 1,250mm ×850mm has been made by galvanised steel sheet (22 gauge), which consisted of four drying trays. The clear window glass (4mm thick) is provided at the top of box. The area of collector designed for the dryer is 1.06 m2 with a DC fan of 10 watt, which will be used for exhausting moisture with the help of a solar panel of 20 Wp. The dimension of two drying trays made of stainless steel angle frame and stainless steel wire mesh was 0.84 × 0.60m and that of two half trays was 0.40 × 0.60m. The drying material can be kept on four trays and placed on angle iron frame in the dryer through an open able door provided on the rear side of the dryer. Six plastic pipes are fixed in the back wall of the dryer just below the trays to introduce fresh air at the base. The maximum stagnation temperature recorded was Design development of photovoltaic-thermal (PVT) hybrid solar dryer 70°C when the outside ambient temperature was 27°C. The PCMs used were paraffin wax (melting temperature 44°C), lauric acid and capric acid which can extend drying hours till late night.