Abstract:
Bread is a staple food prepared from wheat flour and water called dough. Generally baking process needs high temperature in the order of 180-220℃. But the possibility of baking up to a plate temperature of 160℃ was noticeable using well insulated and controlled baking environment. The trend of bread baking system depends on electricity, biomass (wood), fossil fuels which have undesirable environmental effect.
The purpose of this study was design and experimental testing of solar thermal baking system. The uses a 0.89m2 aperture parabolic dish collectors to capture solar radiation via spiral coiled absorber tube embedded in aluminum plate and the hot HTF (Shell Thermal oil) circulates through 8mm outer diameter spirally coiled copper pipe inside the storage unit filled with 6kg solar salt PCM having a melting temperature of 220℃. The thermal storage was considered as a heat source for baking at any time of the day. Aluminum chips of 10% mass fraction was added to enhance the thermal conductivity of the salt which limits the charging/ discharging time. The experimental setup of the system was fabricated using locally available materials and test was conducted during clear sky day. A baking plate surface temperature of 160℃ was achieved and the corresponding baking time was 48 minutes. The maximum storage salt temperature reached was 265℃ with 12 hour of charging time. The quality of bread baked were competitive with the conventional bread baking systems.