Application criteria for the Rotor
Most essential factor for the performance of the rotor is the flow velocity of the water. According to the current state of development, around 300 W can be generated at a flow rate of approx 1.7 m/s. The higher the flow rate, the better (double the flow rate corresponding to eight-fold performance).
As a way to determine flow rate on site, the method of surface speed measurement has been proved successfully:
This is the simplest method to determine the flow rate! A floating body (such as a piece of wood, or paper) flowing a defined distance x, with the river flow down (for example 10 m) to the point at which the rotor is to be installed. Hereby the time which is required for the distance x is been stopped. This measurement should be repeated at least three times and the results are recorded.
The speed is then given by: v = x / t
Although this method is fraught with some inaccuracies, it is simple, easily conducted without measurement technology and finally sufficient.
Other properties that must meet the site relates to the geometry of the water body. The rotor has an immersion depth of 75 cm, i.e., the flow depth should be greater than 1.0 m so that the Rotor is still flown through with water in the event of fluctuations in water level
The Rotor’s width is approx. 1.25 m. Therefore the width of the riverbed does not matter substantially. It should be, depending on the cross-section of the channel at least 3-4 meters.
Further questions to be answered:
- Is there a constant discharge of the river during the entire year? Or how strong is the dependency on the precipitation regime and rainy seasons? In what extent reduces the water flow of the river in the dry season?
- Are there official data or can the local community provide information?
- What are the options for security and ownership for pilot installation?