Aerodynamic design and economical evaluation of site specific small vertical axis wind turbines
The growing demand for renewable energy with a sustainable and low-energy design is the main topic in many countries. This could indeed influence in utilizing small wind turbines which incorporate innovative designs and new materials of construction which may provide an attractive prospect of future applications of power production in the urban environment. In particular, H-rotor type vertical axis wind turbines (VAWTs) are considered as one of the most attractive solutions due to simplicity and ease of manufacturing. Optimized site-specific designs proved reductions in the cost of energy by increasing in annual energy yield and a reduction in manufacturing costs. The greatest benefits were reported at sites with low mean wind speed and low turbulence. The terrain studied here is a site in Fadashk area in the province of south Khorasan in the northeast of Iran. The aim of this work is to design and optimize the site- specific H-rotor type VAWT using the blade element momentum theory (BEM) and a double multiple stream tube model. The results of these analyses were then combined and synthesized for a 1.5 kW H-rotor VAWT with NACA4415 airfoil sections. The economical feasibility of the designed VAWT is finally integrated into the design procedure to predict annual production of electricity. Based on current electricity cost that is 12 cent per kW h in Iran for renewable energies, our evaluation shows a profit of 6 cents per each kW h generated power by the designed VAWT.