Question

7.26. The conversion of the kinetic energy of wind to electricity may be an attractive altemative to the use of fossil fuels. Typically, wind causes the rotor of a turbine to turn, and a generator converts the rotational kinetic energy ofthe rotor into electricity. Power generated by a wind turbine (Ws) can be estimated from the density of the air (p), wind speed (u), and turbine rotor diameter (D) using the following formula лD? 1 W. ти* х п, where m 3D pAu %3D р: 4 = The conversion efficiency (7) is a function of many variables, including the electrical and mechanical properties of the turbine, the material of construction, and the blade design. (a) Develop an equation for the density of air (kg/m2) as a function of the temperature (K) and relative humidity of the air. Use the Antoine equation for the vapor pressure of water, and assume atmospheric pressure equals 1.0 atm (b) A wind turbine with a 30.0-ft diameter and 35.0% conversion efficiency generates electricity on a day when the temperature is 75°F, the relative humidity is 78.0%, and the average wind velocity is 9.50 miles/h. Calculate the generated power in kW.

Answer 1

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