1. Consider the Nordex 1.3MW, 60-m wind turbine with power specifications given in table 6.7 located in an area with 8m/s wind speeds.
a) find the average speed in the wind (W/m^2) assuming Rayleigh statistics.
b) Create a spreadsheet similar to the one developed in Example 6.15 to determind the energy delivered (kWh/yr) from this machine.
c) What would be the average efficiency of the wind turbine?
d) if the turbine's rotor operates at 70% of the BEtz limit, what is the efficinecy of the gearing and generator?
2. For Rayleigh winds with an average windspeed of 8 m/s:
a) how many hours per year do the wind blow at less than 13 m/s?
b) For how many hours per year are windspeeds above 25m/s?
c) Suppose a 31m, 340-kW turbine follows the idealized power curve shown in Figure 6.32. How many kWh/yr will it deliver when winds blow between its rated windspeed of 13 m/s and its fueling windspeed of 25 m/s?
d) Using the capacity factor correlation given in (6.65), estimate the fraction of the annual energy delivered with winds that are above the rated windspeed?