ESET 222: Wind & Solar Energy - Power in the Wind Example

TSR = (rpm * D) / v

14 m/s

56 rpm

<p>224 m/s</p> Signup and view all the answers

<p>32:1</p> Signup and view all the answers

<p>The power output levels off due to the turbine reaching its maximum capacity or rated power.</p> Signup and view all the answers

<p>Tip speed ratio (TSR) is the speed of the blade at its tip divided by the speed of the wind. It is calculated by dividing the speed of the blade tip by the speed of the wind.</p> Signup and view all the answers

<p>The tip of the turbine blade comes under considerable stress due to centrifugal force when it is rotating at high speed.</p> Signup and view all the answers

<p>A TSR of 5 means the tip of the blade is traveling five times faster than the speed of the wind.</p> Signup and view all the answers

<p>Pitch control refers to changing the pitch of the blade with the changing wind speed to regulate the rotor speed.</p> Signup and view all the answers

<p>Stall control involves shifting the blades into a position to stall when the wind speed exceeds the safe limit on the system.</p> Signup and view all the answers

<p>Tip speed = π D N / 60</p> Signup and view all the answers

<p>The tip speed ratio is calculated by dividing the tip speed by the wind speed upwind of the turbine.</p> Signup and view all the answers

<p>The rotor speed (N), rotor diameter (D), and wind speed (v) upwind of the turbine are involved in determining the tip speed ratio.</p> Signup and view all the answers

<p>The tip speed ratio is important in wind energy because it affects the efficiency and power extracted from the wind by the turbine.</p> Signup and view all the answers

<p>The spacing of the towers affects the efficiency of the turbines by influencing the wind flow and the tip speed ratio.</p> Signup and view all the answers

<p>59.3%</p> Signup and view all the answers

<p>Betz efficiency or Betz’s law</p> Signup and view all the answers

<p>35 to 45 percent</p> Signup and view all the answers

<p>Blades are letting too much wind pass by unaffected</p> Signup and view all the answers

<p>As a function of its tip-speed ratio (TSR)</p> Signup and view all the answers

<p>4 - 8</p> Signup and view all the answers

<p>Ratio of tangential velocity at the tip of the blade to the undisturbed upwind velocity</p> Signup and view all the answers

<p>Particular tip speed ratio</p> Signup and view all the answers

<p>The tip speed is at its highest</p> Signup and view all the answers

<p>Prevents the lifting force from acting on the rotor</p> Signup and view all the answers

<p>(v/vo)^3 = (H/Ho)^α.3 = (H/Ho)^3α</p> Signup and view all the answers

<p>50 m</p> Signup and view all the answers

<p>0.20</p> Signup and view all the answers

<p>45%</p> Signup and view all the answers

<p>The power in the wind at the top tip of the rotor is 45% higher than it is when the tip reaches its lowest point.</p> Signup and view all the answers

<p>Wind speed is greatly affected by the friction that the air experiences as it moves across the earth’s surface. Surface winds are slowed considerably by high irregularities such as forests and buildings.</p> Signup and view all the answers

<p>The roughness length (m) is a factor that affects the wind speed at a certain height. It is used in the formula to account for the impact of the roughness of the earth’s surface on wind speed.</p> Signup and view all the answers

<p>For neutral stability conditions, the friction coefficient (α) is approximately 1/7 or 0.143.</p> Signup and view all the answers

<p>The relationship is expressed using the formula v = vo + 0.143 * (z/Ho) * (v - vo), where v is the wind speed at height H, vo is the wind speed at height Ho, α is the friction coefficient, and z is the roughness length (m).</p> Signup and view all the answers

<p>The combination of 9 m/s and 3 m/s winds produces 75% more energy than winds blowing at a steady 6 m/s, despite having the same average wind speed.</p> Signup and view all the answers

<p>The example illustrates the inaccuracy associated with using average wind speeds to predict energy production. It also shows that under certain common assumptions about wind speed probability distributions, energy in the wind can be almost twice the amount found by using the average wind speed.</p> Signup and view all the answers

<p>Tower height affects wind speed by impacting the friction that the air experiences as it moves across the earth’s surface. This, in turn, affects energy production in wind turbines.</p> Signup and view all the answers

<p>Using average wind speeds can lead to significant inaccuracies in predicting energy production. Under certain common assumptions about wind speed probability distributions, energy in the wind can be almost twice the amount found by using the average wind speed.</p> Signup and view all the answers

<p>Wind speed variability significantly impacts wind energy production, as demonstrated by the example of energy production at different wind speeds.</p> Signup and view all the answers

<p>The combination of 9 m/s and 3 m/s winds is more effective in energy production due to the impact of wind speed variability, which results in 75% more energy production compared to winds blowing at a steady 6 m/s.</p> Signup and view all the answers