Notes from article in April/May 2008 HomePower magazine: Microhydro Intake Design.
Includes list of options, with pros & cons, relative cost & complexity of each. Various possibilities exist for the general lay-out of a hydro scheme, depending on the local situation:
- low head with a river barrage
- low head with a channel
- high head with no channel
- high head with channel
A number of essential factors must be kept in mind when designing a micro hydropower system. Those are:
- use of available head
The design of the system has effects on the net head delivered to the turbine. Components such as the channel and penstock cannot be perfectly efficient. Inefficiencies appear as losses of useful head of pressure.
- flow variations
The river flow varies during the year but the hydro installation is designed to take a constant flow. If the channel overflows there will be serious damage to the surroundings. The weir and intake must therefore divert the correct flow wether the river is in low or in high flow. The main function of the weir is to ensure that the channel flow is maintained when the river is low. The intake structure is designed to regulate the flow to within reasonable limits when the river is in high flow. Further regulation of the channel flow is provided by the spillways.
Flowing water in the river may carry small particles of hard abrasive matter (sediment); these can cause wear to the turbine if they are not removed before the water enters the penstock. Sediment may also block the intake or cause the channel to clog up if adequate precautions are not taken.
Flood water will carry larger suspended particles and will even cause large stones to roll along the stream bed. Unless careful design principles are applied, the diversion weir, the intake structure and the embankment walls of the river may be damaged.
In all parts of the water supply line, including the weir, the intake and the channel, sudden alterations to the flow direction will create turbulence which erodes structures and causes energy losses.
Complete article from HP: Microhydro Intake Design
Additional Source Info:
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