The Effect of Compression Ratio on Performance of Generator Set Fuelled with Raw Biogas

Abstract

In order to utilize a raw biogas as a fuel of generator set (gen-set), it is important to figure out optimum operating parameter of the gen-set, i.e. compression ratio. The present work aims to investigate the effect of compression ratio on performance of 3 kW gen-set fuelled with raw biogas and to obtain optimum compression ratio for operation of the gen-set on raw biogas. The gen-set used in the present work is bi-fuel engine, i.e. fuelled with gasoline or LPG. The performance of the engine fuelled with raw biogas in terms of brake power, brake torque, brake specific fuel consumption, and thermal efficiency is evaluated at compression ratio of 7.5, 8.5, 9.5, and 10.5. The work is carried out under electrical load of 240, 420, and 600 Watt. The result indicates that compression ratio affects the rotational speed, brake power, brake torque, brake specific fuel consumption, and thermal efficiency of the gen-set. Optimum compression ratio for the gen-set fuelled with raw biogas is 9.5. At the optimum compression ratio, maximum brake power, brake torque, and thermal efficiency of are 450.37 W, 1.66 Nm, and 46.93%, respectively. Minimum brake specific fuel is 0.59 kg/kWh at the optimum compression ratio.