Study of Performance Characteristics of Small Submersible Pump Run as Hydro Turbine Generator

Pumps including submersible types can be used as alternative micro-hydro turbines with minimal technical changes and at a lower cost compared to conventional turbines. However, pump manufacturers do not normally provide the characteristics curves of their pumps working as turbines. Therefore, establishing a relationship between performances of direct (pump) and reverse (turbine) modes is essential in selecting the proper machine for application. For the purpose of realizing the low cost micro hydropower, the authors modified a low cost submersible electric powered pump rated at 250W and converted it to a micro hydro turbine generator. The performance characteristics of this hydro turbine were tested at various conditions of water flow rate, excitation capacitors and load. The input was measured by using flow meter and pressure gauges while the electrical output was measured by using a power analyzer. The maximum electrical output power generated was 207W at water input power of 986.9W and head of 17.97m. The maximum efficiency operating as a pump was 24.57% while on the hydro turbine generator mode it was 22.02%.