Estimated Power Output from a Simplified Pico Hydropower System

Abstract

Based on the results of no-load tests carried out on a simplified Pico hydropower system currently undergoing development, on-load tests were carried out. A turbine of runner diameter 0.40 m, penstock diameters in the range  and nozzle area ratios in the range  were used for the on-load tests. A 2.5 kW alternator was linked to the turbine using a v-belt drive on pulleys of ratio 6:1. The effective vertical height from the outlet of the reservoir to the plane of the turbine shaft was 6.95 m. A 0.74 kW electric pump was used to recycle the water to the overhead reservoir. The rotational speeds of the turbine and alternator shafts, the volume of water displaced and voltage were measured for each penstock diameter and nozzle area ratio. The measured data were used to compute the system volumetric flow rate and to estimate the power output based on the alternator manufacturer’s specifications. The turbine efficiency was also computed. The system developed a maximum voltage of 224 V with  and a minimum voltage of 111 V with  and . The corresponding estimated power outputs were 2.125 kW and 1.545 kW respectively. The mean maximum and minimum efficiencies based on the estimated power output were 0.85 and 0.618 respectively. The overall results indicate very good potential for the system as a clean, decentralized small power generation unit that gives control to the user.