Response surface methodology optimization of solar powered thresher on soybean

Abstract

Considering the need for threshing, the current energy crisis, the power potential of solar energy, especially, many stand-alone solar installations in rural areas, and their use, a study was undertaken to develop and evaluate a solar-powered multi-crop thresher on soybean. The study was conducted in IARI- Pusa Campus, New Delhi, India aiming to assess the seasonal suitability of the solar operated thresher. The devolved prototype was evaluated on soybean crop and the operational and machine parameters were optimized by response surface methodology (RSM), with central composite design (CCD). Four independent parameters, each at three levels, were taken viz, feed rate, cylinder speed, concave clearance, and spike types to evaluate their effects on three response variables, namely, threshing efficiency, cleaning efficiency, and energy consumption. The response variables ranged from 96.3% to 99.9%, 86.68% to 93.05%, and 1.12 kWh q-1 to 1.74 kWh q-1, respectively, for threshing efficiency, cleaning efficiency, and energy consumption. The cylinder speed significantly affected all response variables. The optimization showed that the best operational and machine settings were 13.62 m s-1 cylinder peripheral speed, 4.3 kg min-1 , feed rate, 20 mm concave clearance, and spike type 3 giving the desirability of 0.799 and the threshing of 116.64 kg hr-1 capacity. However, the season-based optimization with lower feed rates was found advantageous to increase the duration of up to 5 hours of thresher operation in thresher direct coupling mode. Hence it is recommended to adopt the lower feed rate in seasons with reduced insolation