RESERVATIONS

16c. RESERVATIONS - this study, although practically oriented, is largely theoretical, especially since there was not even one practical case of data from a windpower site which detailed energy yield over an annual or even monthly period. Despite this, the Author is reasonably convinced that the data is quite accurate and very useable. The 2 major ways in which reality departs from the simulation is to do with WEC inertia and with wind gusting - sometimes the good windspeeds are unusable by a WEC since it takes too long to respond to brief bursts of wind; also the fact is that for a windpump the applied torque is NOT truly constant over one revolution of the WEC - there is a peak torque, which is the point where the WEC tends to stop when the wind falls. In practice this can be minimised or eliminated by counterbalancing the shaft or the rotor, but putting counterbalancing weights on the rotor can give bad out-of-balance effects if and when the rotor gets to high speed. Of course if computer-logged data as in (16a) above can be matched to known inertias and known torque cycle variation, then true simulations over (8760 * 3600) seconds per year can be done for each location and then more accurate data can be obtained.

One other reservation is of course that for a pump, the water table can vary with the seasons, thus increasing the applied torque and cut-in windspeed as the water table drops.....