DESIGN AND PERFORMANCE TESTING OF SOLAR ENERGY RICE MILLING MACHINE FOR COMMUNITY RICE MILL IN KROK PHRA DISTRICT OF NAKHON SAWAN PROVINCE

Abstract

The objectives of this research were to design, test the efficiency, and perform an economic cost benefit analysis of a solar powered rice milling machine for the community’s rice mill in Krok Phra District of Nakhon Sawan Province. The research method was conducted to examine the problems of rice milling process, design the rice milling machine with the structure made of steel with the power source of electric motor of 1.5 HP. The main components of the machine  consisted of rice pickup truck, rice polishing ball, rice polishing stone, screen sieve, rice husk suction vent with the transmission system installation of a solar power system of solar cell, inverter and battery. According to the testing for finding the efficiency of milling 3 varieties of rice at the appropriate speed of rotation, and the suitable distance of the rubber ball, it was found that the appropriate rice milling of RD 41 was at the speed of 1,290 rpm and the distance of 0.9 mm, that of Chainat 1 at the speed was 1,350 rpm and the distance was 0.9 mm, and that of Hom Pathum Thani at the speed was 1,200 rpm and the distance was 1.0 mm. The results of the testing on the suitable moisture of rice for milling revealed that for the variety of RD 41, the moisture was 14%w.b. which gave the whole grain rice of 0.395 kg. resulting in the efficiency of 62.70%; for the variety of Chainat 1, the moisture was 14%w.b., which gave the whole grain rice of 0.397 kg. resulting in the efficiency was 63.40%; and the variety of  Hom Pathum Thani, the moisture was 13%w.b., which gave the whole grain rice of 0.396 kg. resulting in the efficiency was 63.50%. The comparison of the energy efficiency of rice milling for 5 hours per day, the energy consumption was 5.5 units, and the electricity cost 24.31 baht which could save the electricity bills for 6,344.91 baht. The economic cost benefit analysis found that the payback period was 3.73 years. It was possible to achieve a reduction of 20.86 ton.CO₂. The results of the research would increase the efficiency of rice milling, reduce the energy costs, and be the guideline for farmers’ decisions to make the appropriate investment.