DESIGN STUDY OF A SMALL HYDROELECTRIC SYSTEM

The design and construction of a small hydroelectric system is a model of an undershot waterwheel turbine which was placed in the hydraulic channel and have a sluice gate as a small dam.

The design of the waterwheel had the ability to change the number of its blades and the blades may be taller or shorter this gives bigger or smaller waterwheel diameter. The increasing of the water mass flow rate (0.341-1.765 kg/s) at fixed channel cross sectional area (12.75 cm2) of the undershot waterwheel generated power system shows increased in the following the generator output power (0.0031-0.18 Watt), the mechanical efficiency (10.8%-99.6%), and the electrical efficiency (80.6%-97.9%) and the channel efficiency was decreased (100%-10.9%). The following were fixed volumetric efficiency 72.9%, wheel efficiency 88.2%, and transitional efficiency 97.2%.  The increasing of the channel cross sectional area (11.25-17.25 cm2) at fixed water mass flow rate (1.765 kg/s) of the undershot waterwheel generated power system shows decreased in the following the generator output power (0.201-0.067 Watt), the mechanical efficiency (100%-26.7%) and the electrical efficiency (99.4%-94.4%) and increased in the following the channel efficiency (8.6%-100%), volumetric efficiency (70.9%-75.5%), and wheel efficiency (85.7%-91.3%). The transitional efficiency was fixed at 97.9%.

The maximum overall efficiency of the small generated power system was 6.69 %, the total head was 15.45 cm and the output power was 0.18 W, these values obtained at number of blades 36, number of revolutions per minute 57 rpm, waterwheel radius 22 cm, maximum I water mass flow rate 1.765 kg/s, and channel cross sectional area 12.75 cm2. The theoretical extrapolation of the waterwheel diameter (0.44-2 m) and the water head (0.1554-5 m) gives that the output generated power was increased (0.18-675 Watt).