Increasing access to modern forms of energy in developing countries is a
crucial component to eliminating extreme poverty around the world. Pico-hydro
schemes (less than 5-kW range) can provide environmentally sustainable electricity
and mechanical power to rural communities, generally more cost-effectively than
diesel/gasoline generators, wind turbines, or solar photovoltaic systems. The use of
these types of systems has in the past and will continue in the future to have a large
impact on rural, typically impoverished areas, allowing them the means for extended
hours of productivity, new types of commerce, improved health care, and other
services vital to building an economy.
For this thesis, a laboratory-scale test fixture was constructed to test the
operating performance characteristics of impulse turbines and electrical generators.
Tests were carried out on a Pelton turbine, two Turgo turbines, and a permanent
magnet alternator (PMA). The effect on turbine efficiency was determined for a
number of parameters including: variations in speed ratio, jet misalignment and jet
Under the best conditions, the Turgo turbine efficiency was observed to be
over 80% at a speed ratio of about 0.46, which is quite good for pico-hydro-scale
turbines. The Pelton turbine was found to be less efficient with a peak of just over
70% at a speed ratio of about 0.43. The lower efficiency can be largely attributed to
the rougher surface on the turbine blades. Both turbine types had lower than expected
speed ratios which were likely caused by inefficiencies in the turbine. Tests of jet
misalignment showed that moving the jet to the inside or outside edge of the buckets
caused a drop in efficiency of around 10-20% as well as shifting the optimal speed
ratio down 0.03 (6.5%). For the PMA, the generator efficiency peaked at just less than
70%. The data demonstrate the impact of impedance matching on generator efficiency
for a PMA.
Currently published literature provides few details specific to Turgo turbines or
PMAs despite their suitability for pico-hydro. Nonetheless, Turgo turbines are
currently available on the market (at least in the US) and offer a viable option for picohydro
schemes, particularly in the medium head range. This thesis describes an
experimental investigation of impulse turbines, including both Turgo and Pelton
turbines, which will be useful for implementation of rural electrification projects. The
results stress the importance of proper system design and installation in order to ensure
a successful scheme.