Optimizing Performance of Windmills Using a Variable Stroke Mechanism

Wind powered water pumping systems are an attractive alternative for developing countries, as well as for applications in remote areas. Although many existing systems offer good performance, not all are well adapted to developing countries. A pumping system such as a Savonius rotor attached to a reciprocal pump is an appropriate solution because of its simple construction, ease of maintenance and low technology requirement. Usually, the design of such systems is based on the proper selection of wind turbines and pumps for the local conditions. Maximum power conversion efficiency is achieved when the proper combination of wind turbine rotational velocity and water pump outflow is satisfied. Unfortunately, this situation occurs at one, and only one combination of these conditions. It was therefore required to investigate a mechanism that will vary the load on the rotor as wind speed increases, thus maintaining the wind turbine at an optimal system rotational speed. Theoretically, a variable stroke feedback mechanism is indicated to be a proper solution for low technology applications.