5. Conclusions
The development of a 6.2 kW micro-hydro turbine unit and test
facility was presented. The turbine unit was designed to incorporate
a commercially available pump impeller operated in turbine
mode, together with custom spiral casing and guide vane mechanism
for inlet flow control. Steady state experimental testing over
the full operating range indicated a maximum overall efficiency of
79%, in good agreement with PAT theory. The net head and output
power at rated conditions were somewhat higher than predicted by
the method of Sharma [6], while the flow rate at rated was slightly
less than expected. Importantly, in the context of micro-hydro and
energy recovery systems, while slightly more complex than a
traditional PAT system the turbine demonstrated near peak efficiency
operation over a wide range of flow conditions, as indicated
by the weighted-average-efficiency. The designed micro-hydro
turbine unit thereby addresses the main drawbacks of pumps
operating in turbine mode, providing a low cost alternative
generating solution for application in remote area power supply
and industrial energy recovery systems.