The Archimedes, a Dutch renewable energy start-up has created an efficient, almost silent small rooftop wind turbine. It comprises three circular blades wrapped around one another and then expanded. This creates a three-dimensional conical turbine, similar to elongated shells found on the beach. The design ensures that wind is drawn into the turbine with an average yield many times higher compared to a normal urban windmill propeller. The Liam F1 turbine could generate 1,500 kWh of energy per year at wind speeds of 5m/s, enough to cover half of an average household’s energy use. Combined with rooftop solar panels, a house could run off grid. The Archimedes is also working on even smaller wind turbine designs that could fit on LED lamp posts or on boats to power them.
www.treehugger.com/silent-wind-turbines-could-generate-half-household-energy-4857821