Week 7

Question 1

How is wind produced

Answer 1

Uneven heating of earth (Eg- land/sea-land gets hotter) creates convection currents. Air moves from hot to cold.

Question 2

Advantages of wind energy

Answer 2

-Renewable
-Clean energy source (no pollution)
-Less space required
-Used in remote areas
-Creates jobs

Question 3

Disadvantages of wind energy

Answer 3

-Unreliable source
-Noisy
-Visual pollution
-Harms wildlife (eg-birds)

Question 4

Facts about HAWT (horizontal axis wind turbine)

Answer 4

-Taller=more efficient (adv)
-Layout: 4x diameter left/right
10x diameter up/down
-YAW mechanism needed to face wind (disadv)

Question 5

Facts about VAWT

Answer 5

-Receives wind from all directions (adv)
-Generates electricity at lower speeds (adv)
-Gearbox and generator housed at bottom for ease of maintenance (adv).

Question 6

Explain how stream tube models air

Answer 6

Inlet: Wind enters at v1 and atmospheric pressure.
At rotor: air expands, pressure increases, velocity decreases- turbine extracts energy which causes the reduced pressure.
Outlet: Air expands, cross-section increases so pressure decreases to atmospheric