About 30% of perishable agriculture products are spoiled during post-harvest processing. This study has been taken up for the enhancement of existing post-harvest processing facilities using renewable energy by developing a continuous solar roaster (CSR) for the on-farm roasting of different agricultural products. Existing roasting techniques are not adoptable for the growers of developing countries due to high initial investment and rapidly escalating prices of non-renewable energy resources. A 10 m2 Scheffler reflector is used to generate thermal energy by converging the incoming direct normal irradiance (DNI) at a 460 mm diameter copper coil heat exchanger which is transferred to a 2000 mm long and 450 mm in diameter roasting cylinder by circulation of thermal oil. Hot thermal oil delivers the absorbed heat to products while flowing in a semi-circular oil jacket (13.5 liter capacity) installed beneath the roasting cylinder. Groundnuts were fed into the roasting cylinder through a 0.015 m3 capacity feeding hopper and slide towards discharge chute with the help of ribbon type paddle screw conveyor. Performance evaluation results showed that more energy can be drawn in winter season than the summer with standing Scheffler reflector in northern hemisphere and maximum cooking power was calculated to be 3279 W under the average DNI of 815 W/m2. Central composite rotatable design (CCRD) technique was selected to design the experiments in Design Expert® (Version: 11.0.5.0 64-bit) software to investigate the single and interactive effects of operating parameters of CSR. The optimization results for maximum feeding capacity (15 kg) and minimum thermal oil flow rate (0.01 L/s) revealed that the conveyor speeds of 1.42 rpm, 0.99 rpm and 0.69 rpm corresponding to 14+0.1, 20+0.1 and 29+0.1 min roasting time resulted in light, medium and dark quality groundnut roasting respectively. Final moisture contents of groundnut kernels were found to be 1.99, 1.73 and 1.34% against the L* value of 53.42, 48.77 and 43.41 at light, medium and dark roasting respectively. On a sunny day, 140 to 288 kg groundnuts can be continuously roasted subjected to light to dark roasting conditions respectively with satisfactory food quality. The payback period of CSR was assessed to be 1.7 to 3.9 years depending upon the alternate source used for equivalent energy generation. It was also estimated that CSR can generate about 55 MWh energy for roasting in expected life span of 10 year. For equivalent energy production, CO2 emission by wood, coal, diesel, kerosene and gas were found to be 21.45, 19.25, 14.85, 14.30 and 11 thousand tons respectively. The overall system efficiency was found to be 39 to 41%.