Objective
To demonstrate an entirely novel, pneumatic method of low head hydro-electric generation which uses water flow over a partially air filled flexible membrane to produce an oscillating air flow which in turn drives a Wells air turbine.
In spite of strenous efforts, the device has not operated fully satisfactorily or continuously. Most of the problems have been caused by the membrane. This was to be expected as the design, fabrication and installation of the membrane all presented novel problems. In addition, the performance of the Wells turbine has been disappointing on two counts; its efficiency has apparently been lower than expected and its rotor failed as the result of slippage of the blades in the central hub. The latter has been especially disappointing as the manufacturer has since left the renewable energy market and so repairs cannot be readily carried out.
As a result of these problems, it has not proved possible to assess the long-term viability of the demonstration unit, nor of replication units based on it, although a considerable amount of information has been accumulated which should be of value in defining the device characteristics in any future designs.
The site for this project is a disused millstream at Riverside House on the River Derwent. Water is syphoned over a weir and is temporarily stored in an upper pond. The water is then passed through an inclined duct over a flexible membrane which forms two air bags which oscillate and cause the air to be driven back and forth through a Wells air turbine. The Wells turbine permits unidirectional output shaft rotation for air flow in either direction across the turbine blades. The electricity produced by the unit will be sold to the local supply authority.
The design parameters are;
Water - head 2.75 m
- flow 9 m/s - power 243 kW (gross)
Air - flow 20 m/s
Generator - power 150 kW (output)
- voltage 415 V, 3 phase, 50 50 Hz
Duct/membrane
- length 30 m
- drop 2.8 m
- width 6 m
- height 2.75 m 5 m
Topic(s)
Data not availableCall for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
DG14 0RG Canonbie
United Kingdom