Energy, exergy and economic analysis of an indirect type solar dryer using green chilli: A comparative assessment of forced and natural convection

The energy, exergy and economic analysis of indirect type solar dryer (ITSD) was performed while drying green chilli under forced and natural convection. Fans powered by PV panels were used for forced convection setup. The collector and drying efficiencies of the forced convection dryer were found to be 63.3% and 10.4% and the same was 53.84% and 8.90% in natural convection ITSD, respectively. The specific moisture extraction rate (SMER) of green chilli in ITSD was found to be 0.6526 and 0.5603 kg/kW-h under forced and natural convection, respectively. The exergy output of the solar air collector was 3.61 to 677.84 J/kg and 6.50 to 1447.96 J/kg under forced and natural convection, respectively. The exergy loss of the drying cabinet was in the range of 0.2 to 327.76 J/kg and 0.84 to 664.63 J/kg in forced and natural ITSD, respectively. The exergy efficiencies of collector and drying cabinet were in the range of 1.91%, 56.12% and 2.26%, 51.85% for forced and natural convection setups, respectively. The exergy sustainability indicators were estimated. The exergetic performance of ITSD was improved with forced convection compared to natural convection ITSD. Economic analysis was performed and the payback period was found to be less in forced convection due to decreased drying time. Uncertainty analysis was carried out.