Experimental Investigation of Power Density Enhancement for a Small Wind Turbine Augmented With a Novel Deflector

This paper explains a novel concept for wind power density enhancement through the use of specially shaped static wind deflector structures. The design and fabrication of the deflectors and the experimental results are explained. The general wind enhancement concept is further divided into two separate but related versions. The first deflector version discussed herein is a closed or constrained-flow device proposed for energy recapture from industrial-scale ventilation exhaust air. The second deflector version discussed herein is an open or unconstrained-flow device proposed for low wind velocity (< 4 m/s) applications and thus offers potential for wind power generation in built-up urban environments. Experiments associated with the two design adaptations were performed on a test-duct and in a wind tunnel, respectively. The test results showed velocity increases (factors of 3 and 1.7 respectively). The test-duct results for the constrained-flow device also showed turbine power output enhancement by a factor of approximately 20. Neglecting other losses, such a ratio would provide a theoretical power improvement of about 5 times over the base flow velocity. The term Wind Powered Deflector (WPD) was coined to describe the devices discussed herein.