Fundamentals of Wind Energy
Fundamentals of Wind Energy Paul Gipe, wind-works.org Power in the Wind P1AV 3 2 Where is air density (kg/m3), A is area (m2), and V is velocity (m/s); thus 2V3 = 8P Paul Gipe, wind-works.org Seasonal Wind Distribution Avg. Monthly Wind Speed (mph) 18 16 ! ! ! ! ! 14 ' & ' & ! ' &! ' ! ! ! & ! & ' ! 12 & & ' 10 ' & & & && ' ' 8 ' ' ' 6 ! Amarillo, Texas 4 & Erie, Penn. ' San Francisco, Calif. 2 0 Jan Feb March April May June July Aug Sept Oct Nov Dec Month Paul Gipe, wind-works.org Rayleigh Wind Speed Distribution Frequency of Occurrence % 0.16 0.14 5 m/s 6 m/s 0.12 7 m/s 0.1 0.08 0.06 0.04 0.02 0 01234567891011121314151617181920 Wind Speed Bin Paul Gipe, wind-works.org Increase in Wind Speed with Height " V=Vo (H/Ho) 1.6 Wind Shear Exponent 1.5 , 0.1) 0.14 (1/7)& 0.2* 0.25 * * 1.4 * * & & * & 1.3 & * ) & ) ) 1.2 * & ) ) , , & ) , , * ) , 1.1 & , ) , , 1 &),* 1 1.5 2 2.5 3 3.5 4 4.5 5 H/Ho Paul Gipe, wind-works.org Increase in Power with Height 3" P=Po (H/Ho) 3.5 * Wind Shear Exponent * 3 , 0.1) 0.14 (1/7)& 0.2* 0.25 * * & 2.5 & * & & 2 * ) & ) ) * & ) ) , , 1.5 & ) , , , * ) , & , ,) 1 &),* 1 1.5 2 2.5 3 3.5 4 4.5 5 H/Ho Paul Gipe, wind-works.org Change in Wind Speed & Power with Height 2 X Height 5 X Height 25 to 50 m 10 to 50 m Wind Speed 1.1 1.25 Wind Power 1.35 1.99 1/7 (0.14), Low Grass Prairies Paul Gipe, wind-works.org Annual Energy Output (AEO) Estimating Methods • Back-of-the-Envelope (Swept Area) Simple Approximation • Power Curve & Speed Distribution Method Used by the Pros Accuracy Dependent Upon Data • Manufacturers’ Tables
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