.We believe that the river turbine is the best choice
for small and medium river sites. The advantages that river turbines have over
propeller type turbines include:
i) their ability to have a greater diameter than depth which enables more area to be swept in a shallow stream and therefore more power production per turbine,
ii) the vertical shaft provides easy maintenance as the electrical components and bearings are above water, and
iii) increased efficiency over propeller turbines not specifically designed as water current turbines.
The river turbine typically rotates at 45 to 90 rpm, the most efficient range being 55 to 70 rpm. At higher rotational speeds the turbine blades reach their stall point and therefore the turbines overspeed is naturally limited, at this point power production also starts to taper off. The water flow speed that is generally accepted as the minimum for power production is 0.8 m/s ( 2.6 ft/s ). As will be shown in the applications section every increase in velocity over this minimum provides a dramatic increase in power production.
i) their ability to have a greater diameter than depth which enables more area to be swept in a shallow stream and therefore more power production per turbine,
ii) the vertical shaft provides easy maintenance as the electrical components and bearings are above water, and
iii) increased efficiency over propeller turbines not specifically designed as water current turbines.
The river turbine typically rotates at 45 to 90 rpm, the most efficient range being 55 to 70 rpm. At higher rotational speeds the turbine blades reach their stall point and therefore the turbines overspeed is naturally limited, at this point power production also starts to taper off. The water flow speed that is generally accepted as the minimum for power production is 0.8 m/s ( 2.6 ft/s ). As will be shown in the applications section every increase in velocity over this minimum provides a dramatic increase in power production.
Power Output
As an alternative to the equations the following graph
allows a quick comparison of the effects of changing the area and water
velocity. To calculate the permissible height for a site take the actual depth
and subtract 0.1 m ( 4") for shallow, high speed flows - those greater than 1.3
m/s ( ~ 4ft/s) and 0.3 m (12") for lower speed flows. There are 2
width(diameter) standards, 1.25m and 2.5m. Other sizes may be accommodated at a
premium.
Cost
Hydro turbines produce power 24 hours per day, every day and
as a result can provide a very cost-effective alternative when compared to other
forms of renewable energy. The initial capital cost is an important part of the
decision to pursue any particular avenue for energy production, as a result
Alternative Hydro turbines . offers a range of options and
sizes. The key element is the turbine itself, a person can fabricate the
remainder with some technical ability, and accordingly the turbine is offered
separately. From the turbine only to a complete generating system we can supply
your needs.
The base turbine consists of a 0.45 m² ( 5.4 ft² ) turbine with a diameter of 1.25m (4.1 ft) and a single support arm. The price of this and any other unit is available on request. Shipping and mounting platforms are not included in these prices.
Further comments on any potential site are available upon request. Some information that would aid in commenting would include the following; water velocity, available depth and width, degree of seasonal variation, and the roughness of the riverbed. Metric hardware is available at a premium.
The base turbine consists of a 0.45 m² ( 5.4 ft² ) turbine with a diameter of 1.25m (4.1 ft) and a single support arm. The price of this and any other unit is available on request. Shipping and mounting platforms are not included in these prices.
Further comments on any potential site are available upon request. Some information that would aid in commenting would include the following; water velocity, available depth and width, degree of seasonal variation, and the roughness of the riverbed. Metric hardware is available at a premium.