Abstract: The invention relates to a vertical-axis wind turbine and at least 2 turbine blades, wherein every turbine blade is connected via a supporting arm and a connecting element that can be purely tensile-loaded to the rotatable vertical axis. According to the invention, between the connecting element that can be purely tensile-loaded and the supporting arm a blade is provided that is convex at an angle of attack side defined by the turbine blades and is concave at the other side. The invention also relates to a method for manufacturing a wind turbine.

Abstract: The present invention relates to a solar collector having an integrated heat storage. Such a solar collector comprises a housing which comprises a bottom plate and a transparent cap, wherein between an involute mirror and the transparent cap a storage tank for the storage of water is provided. The solar collector according to the invention is characterized in that a shielding is provided between the transparent cap and the storage tank, which leaves the part of the storage tank that is situated lower uncovered. By using the solar collector according to the invention a higher thermal yield can be achieved while using less materials.