A Belgian company named Turbulent has developed turbine systems requiring a head of only 5 feet (1.5 meters) and a flow of only 53 cu. feet/second (1.5 cu. meters/second) to generate a useful amount of electric power, according to company literature. The systems are also compact and relatively simple to install, which could make them suitable for installation at former tide mill sites, where water height difference is determined by tidal range at the site. Such installations could produce 15 kW or more as distributed energy sources.
Turbulent’s vortex turbines extract energy from water falling vertically from an input basin shaped to create a swirling low-pressure flow (low pressure vortex) before the water enters the turbine. The company says installations do not obstruct normal water flow and let “all fish and aquatic life pass by unharmed.”
In addition to the turbine, the core unit contains a gearbox and high efficiency generator. Turbines are available with impeller diameters from 51 inches (1.3 meters) to 75 inches (1.9 meters) and with power output capacities from 15 kW to 70 kW.
For more about vortex turbines, visit the Turbulent website.
I’m approaching this as a thought experiment, what it would take to install this device on an old tide mill site, last operational in the 1840s. No building remains, but there are still the dams that enclosed the mill pond.
The examples given around the world, seem more suited to river mill conditions than a tide mill here in New Castle, NH. I wonder:
(1) How much width of the dam is required to install the device.
(2) Is it programmed for the local tide cycle to let water flow in to fill the pond to the required 5ft. head? Does that happen via the generator channel or does it require a separate channel and is it programmed to operate that? The video suggests continuous low-flow outflow and generator outflow, but does not show inflow.
(3) Permitting becomes critical. The water body and dam remnant are in waters controlled by the state.
(4) Electrical transfer is critical, to connect to the local power grid and presumably have that happen on adjacent private property, since all the land surrounding the tide mill is owned by individuals — maybe up to a dozen.
Good questions! Much more analysis probably needed to determine whether it would be practical to apply this vortex turbine technology to former tide mill sites.