Design and power production of small-scale wind turbines

Wind is one of the most used renewable energy sources for general applications due to its power availability. There are several studies that use wind energy in small-scale systems, however few analyse the lower then 10000 Reynolds number range and the usual approach consists in apply a commercial turbine, or adapt one from other system, to a commercial generator, providing low efficiency system. This paper uses Schmitz theory to design wind turbines in the centimetre scale based on three airfoils, BW3, E62 and S1223. A wind tunnel was used to determine the power coefficient and maximum power transfer, with a small generator. However, the problem with the use of wind energy in urban areas is the variability of the available power since most of the time the wind speed is very low. Therefore, this work includes a study on remote monitoring using a wind turbine to feed a wireless sensor node and a vertical axis wind turbine was used to compare the systems behaviour. The results demonstrate these systems are capable to feed the load and charge a battery even with very low average wind speed.