Improving the efficiencies of pelton wheel in Micro-Hydro Power plants

Most Micro Hydro Power Systems (MHPS) in developing countries, are not delivering their best possible power output due to sub-optimal design and construction of their various components. For existing MHP plants the turbine is much more adaptable to retrofit than any other part of the MHP while keeping the overall project cost per kilowatt produced within acceptable range. Therefore this becomes a feasible cost effective strategy to improve the efficiency of a hydro- turbine with the effect of improving the overall efficiency of the system. This research showed that the main factors that affect efficiency of Pelton wheel turbines, which are commonly used in Southern Africa, are the fabrication processes; material used; the control of the water jet movement and flow rate. The fabrication process and the material used determine the roughness of the turbine produced. The roughness determines the friction which in turn affects the efficiency of a turbine. Current fabrication processes were compared to other processes such as laser and electron beam cutting and welding, pressure die casting, investment casting and milling. These processes and use of stainless steel resulted in the least rough finish. This gave an overall increase of 20 - 25% on the turbine efficiencies.