Lesson Notes By Weeks and Term v4 - SHS 3
RENEWABLE ENERGY SYSTEMS
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RENEWABLE ENERGY SYSTEMS
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Engineering
Class: SHS 3
Term: 2nd Term
Week: 8
Grade code: 3.2.2.LI.2
Strand code: 2
Sub-strand code: 2
Content standard code: 3.2.2.CS.1
Indicator code: 3.2.2.LI.2
Theme: ENERGY SYSTEMS
Subtheme: RENEWABLE ENERGY SYSTEMS
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This lesson introduces the fundamental components of two crucial renewable energy systems: wind and bioenergy. In Ghana, as we face challenges with 'dumsor' (power outages) and seek sustainable ways to power our homes, schools, and industries, understanding these technologies is vital. Wind energy has great potential along our extensive coastline (e.g., Ada, Keta), while bioenergy offers a way to turn our abundant agricultural waste (from cocoa, cassava, animal farming) and urban waste into valuable fuel. This lesson will break down these complex systems into their basic parts, explaining what each part does to help us generate clean energy.
This section breaks down the two energy systems into their core components and explains their functions in detail. Part A: Wind Energy Systems
A wind turbine is a machine that converts the kinetic energy (energy of motion) from the wind into electrical energy. The most common type is the Horizontal-Axis Wind Turbine (HAWT).
Basic Components of a Wind Turbine: Rotor Blades: What they are: These are the large, wing-shaped structures that are most visible on a turbine. Most modern turbines have three blades. Function: Their primary function is to capture the kinetic energy of the wind. They are designed with an aerodynamic profile similar to an airplane's wing. When wind flows over the curved surface, it creates a pressure difference (lift), causing the blades to rotate. This rotation is the first step in the energy conversion process. Analogy: Think of the blades as the sails of a modern ship, but instead of pushing the structure forward, they are designed to spin a central hub. Nacelle: What it is: The large housing unit located at the top of the tower, directly behind the rotor blades. Function: The nacelle acts as a protective casing for all the critical power-generating components of the turbine. It is like the engine room of the system. Inside the nacelle, you will find the gearbox and the generator. Gearbox: What it is: A mechanical system of gears located inside the nacelle, connecting the low-speed shaft from the rotor to the high-speed shaft of the generator. Function: The rotor blades turn relatively slowly (e.g., 15-20 revolutions per minute - RPM). However, generators need to spin very fast (e.g., 1500-1800 RPM) to produce electricity efficiently. The gearbox increases the rotational speed from the blades to the level required by the generator.