Wind

Resources

How winds exist

pressure and temperature

Horizontal pressure and vertical temperature

Pressure - Horizontal & Temperature - Vertical.,

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Areas of high pressure air moving to areas of low pressure create wind’s horizontal movement.

As air heats up, it becomes less dense and rises. The opposite happens with cold air, becoming more dense and sinking. These two processes create a flow of air that creates vertical movement of air.

Coriolis effect

Areas at the equator spin faster than areas at higher or lower latitudes, since it covers the most distance over 24 and everywhere on earth has the same time period.

Therefore, if some clouds want to move to a different latitude, they will have a different inertia to the earth and that latitude, causing the to either go by faster or lag behind. This is where trade winds come from.

factors that affect wind strength:

  • temperature

  • wind patterns

  • Latitude and longitude

  • Proximity to water

  • Altitude

    • less turbulence from objects and the ground, allowing for greater pressure differences, leading to faster wind speeds.

  • Proximity to big and tall objects

    • cause turbulence

Evaluating resource

WIND RESOURCE MAP (or wind distribution)

Allows us to pick location with the best wind speeds.

WIND SPEED DISTRIBUTION

how to calculate energy yield:

Draw both graphs → for a given speed, multiply the number of hours by the power → sum all the values for each wind speed together.

Power equation is the normal one for a turbine and some flow of a substance:

P = 0.5 * ρ * A * v³, where P is power, ρ is air density, A is the rotor area, and v is the wind speed.

ρ_air = 1.23 kg/m³

Utilisation

Parts

Wind turbine | Renewable Energy, Efficiency & Design | Britannica

acronym: BRAGGY

  • Blades: Capture wind energy and convert it to rotational energy

  • Rotor: Connects the blades to the generator

  • Anemometer: Measures wind speed

  • Gearbox: Adjusts the rotational speed for the generator

  • Generator: Converts mechanical energy into electrical energy

  • Yaw system: Aligns the turbine with the wind direction

Extra:

Number of blades

1 BLADE:

  • captures the least amount of energy

  • easiest to install

  • requires counterbalance

  • overall no savings

2 BLADES:

  • captures more than 1 blade but less than 3

  • still, no overall savings over a 3 blade

3 BLADE:

  • provides optimal balance between efficiency and stability

  • commonly used in modern wind turbine designs due to their enhanced performance

Pitch vs stall control

Pitch control = system where the angle of the blades is adjustable for optimum power

pitch control graph

Stall control = system where the angle of the blades are fixed in place to prevent

stall control graph

key differences in the graph you need to know:

  • the power trend from cut-in speed to rated wind speed is relatively the same

  • the trend changes after the rated wind speed, where pitch control maintains a higher power and stall control loses loses power at greater speeds.

What to understand: stall control can’t maintain motion adequately when under wind overload, so the power decreases. In contrast, pitch control adjusts the blade angle to optimise performance, ensuring that power output remains stable even in high wind conditions.