Sustainable innovation for fermented cassava roasting: Examining the potential of parabolic dish solar collectors and thermal energy storage.

Fermented cassava roasting is an energy-intensive process that is commonly used to produce gari, a popular food in Nigeria made from cassava. Traditional roasting methods use firewood as an energy source, which is inefficient and harmful to the health of those who inhale the smoke (mainly women and children in rural communities) and contributes to deforestation. This work aims to investigate a developed fermented cassava roasting system driven by a concentrated parabolic solar collector. Important data on the gari production food chain was obtained from a work-study in a rural community: temperatures and moisture content. The roasting temperatures range between 85(o)C - 100(o)C. The parabolic dish solar collector was designed and fabricated to achieve temperatures between 118(o)C-154(o)C at optimum tilt angles at Port Harcourt (4°54' 22.86″N, 6°55' 27.52″E) climatic conditions. The focal length ranges between 50 mm and 80 mm, and the fluctuation of the focal point position was considered for the thermal storage system design. Gravel was used as a thermal storage, and heat transfer was enhanced through small internally placed mild steel rods. The experimentally obtained average total fry/roast time per batch (40g) was 24 min, which is greater than the theoretically obtained value of 8.5 min. The fermented cassava roasting experiment was conducted for three days with favourable weather conditions, achieving a maximum temperature of 101(o)C. This innovation is important in addressing the health risks associated with traditional fermented cassava roasting methods and moving towards zero-emission and zero-poverty innovative systems.