WEBC07 06/04/2015 21:59:42 Page 389 (Continued ) City (Pop) JAN FEB MAR APR MAY JUN JUL

Chapter 7, Problem 7.26

(choose chapter or problem)

WEBC07 06/04/2015 21:59:42 Page 389 (Continued ) City (Pop) JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Yr. Mean Bridgeport, CT (137912) hr(%) 69 69 69 68 74 77 77 78 80 78 76 73 T(F) 29.9 31.9 39.5 48.9 59 68 74 73.1 65.7 54.7 45.1 35.1 u(mph) 12.5 12.9 13 12.4 11.1 9.9 9.4 9.5 10.5 11.3 12 12.1 T(K) (kg/m3 ) u(m/s) W_ s(kW) Sacramento, CA (1394154) hr(%) 90 88 85 82 82 78 77 78 77 79 87 88 T(F) 51.2 54.5 58.9 65.5 71.5 75.4 74.8 71.7 64.4 53.3 45.8 51.2 u(mph) 7.3 8.4 8.6 9 9.6 8.9 8.4 7.4 6.4 6 6.4 7.3 T(K) (kg/m3 ) u(m/s) W_ s(kW) (d) Plot the power variation over the course of a year for all three cities. How do the cities compare as locations for wind turbines? (e) TheaverageelectricityconsumptionintheUnitedStatesisapproximately 12,000 kWh percapita per year. On awind-turbine farm, a singleturbine occupies a space of 1000 m2 .Estimatethe number ofturbinesthat would be required to meet the electricity needs of each of the three cities listed in the table if the turbines were operated continuously. Then estimate how many acres and hectares each farm would occupy. (f) The numbers of turbines actually put in place to meet the power requirements of the three cities would all be greater than the numbers calculated in Part (e). List three reasons for the calculated quantities to be underestimates.