Design and experimental Analyses of enhanced heat transfer performance in solar powered Injera baking pan using Cu/Oil and A12O2/Oil nanofluids

Abstract

There are demands for wood in high populated areas in Ethiopia due to the fact that many people used wood, residue of crop, animal dung (dried) as fuel for cooking. This has led to ecological damage and local scarcity in these areas. Most people in Ethiopia use local baking pan to prepare their food like Injera. This local baking pan has drawbacks like low efficiency due to the poor thermal efficiency. Using wood as the primary source for the baking pan also has negative health, economy and environmental impact like deforestation. This has also led to smoke (indoor) pollution which affects the health of the most vulnerable like women and children. This research is aimed at investigating the performance enhancement of Injera baking oven powered by solar energy by using copper-oil and aluminium oxide-oil nanoparticles. Solar collector (parabolic) via trough assembly, baking pan assembly, the pump, reservoir of thermal fluid, working fluid reservoir (cold temperature), and connecting pipes made the system. Copper-oil and aluminium-oil were used as fluids for heat transfer. These fluids have diameters of 30–50 nm.At volume concentration of 0.3%, the solar collector efficiency for copper-oil was above 60% approximately which is the highest value. This is followed by the aluminium oxide-oil with efficiency of approximately 56% while the ordinary oil showed efficiency of 48%. The average thermal efficiency for copper-oil was 43% while that of aluminium oxide-oil was 39%. The ordinary oil stood at 35% average thermal efficiency. The copper-oil as a working fluid performed better than that of aluminium oxide-oil at 0.3% volume concentration. Likewise, at the volume concentration of 0.05%, the average thermal efficiency for copper-oil was 39% while that of aluminium oxide-oil was 35.1%. Ordinary oil stood at 34.9% at 0.05% volume variation. Copper-oil as a working fluid performed better than other working fluids at volume concentration of 0.05%