Lesson Notes By Weeks and Term v4 - SHS 3
ENERGY EFFICIENCY AND CONSERVATION
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ENERGY EFFICIENCY AND CONSERVATION
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Engineering
Class: SHS 3
Term: 2nd Term
Week: 12
Grade code: 3.2.3.LI.2
Strand code: 2
Sub-strand code: 3
Content standard code: 3.2.3.CS.1
Indicator code: 3.2.3.LI.2
Theme: ENERGY SYSTEMS
Subtheme: ENERGY EFFICIENCY AND CONSERVATION
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Welcome, future engineers! Today, we are discussing a topic that affects every single one of us in Ghana: Energy Efficiency and Conservation. We all know the frustration of "dumsor" (intermittent power cuts) and have seen our parents or guardians worry about the monthly ECG (Electricity Company of Ghana) bill. This lesson is not just about theory; it's about practical solutions that can save us money, reduce the strain on our national power grid, and protect our environment. By understanding the devices that help us save energy, you can make informed decisions in your homes, schools, and future workplaces. This knowledge empowers you to be part of the solution to Ghana's energy challenges.
A. Fundamental Definitions
Before we discuss the devices, we must understand two key terms that are often used interchangeably but have different meanings. Energy Conservation: This is the practice of using less energy. It is primarily a behavioural change. It means making a conscious effort to reduce energy consumption. Example: Switching off lights when you leave a room, unplugging your phone charger when not in use, or taking shorter showers to use less hot water. Energy Efficiency: This means using technology to get the same (or better) output or service with less energy input. It is a technological approach. Example: Replacing an old 100-Watt incandescent bulb with a 10-Watt LED bulb that produces the same amount of light. You still get the light you need, but you use 90% less energy.
Analogy: Energy conservation is like deciding not to drive your car to the market to save fuel. Energy efficiency is like buying a new car that uses much less fuel to travel the same distance to the market. We need both to be effective. B. Devices for Energy Efficiency and Conservation
Let's explore the various devices, how they work, and where they are applied. High-Efficiency Lighting Device: Light Emitting Diode (LED) Bulbs and Compact Fluorescent Lamps (CFLs). How it Works: LEDs: Pass electricity through a semiconductor to create light directly. This process is very efficient and generates very little heat. CFLs: Pass an electric current through a tube containing argon and mercury vapour, creating invisible ultraviolet light that excites a fluorescent coating (phosphor) to emit visible light. Both are far more efficient than traditional incandescent bulbs, which work by heating a tiny wire (filament) until it glows. About 90% of the energy in an incandescent bulb is wasted as heat, not light! Application Areas: Homes: In living rooms, kitchens, bedrooms, and outdoor security lights. Replacing just five incandescent bulbs with LEDs can save a household significant money on their ECG bill. Schools: In classrooms, libraries, offices, and hallways. Good lighting is essential for learning, and LEDs provide it cheaply. Industries/Offices: In factories, warehouses, and office buildings. They last longer, reducing maintenance costs in addition to energy savings. Energy-Efficient Appliances Device: Refrigerators, Air Conditioners, and Washing Machines with high energy efficiency ratings. How it Works: These appliances are designed with advanced technologies like better compressors (in fridges/ACs), improved insulation, and smart sensors to perform their function using less electricity. In Ghana, the Energy Commission's star rating label (the yellow sticker) helps consumers identify efficient models. More stars mean more efficiency. Application Areas: Homes: A refrigerator is one of the biggest energy consumers in a Ghanaian home because it runs 24/7. Choosing a 5-star model over a 1-star or an old, unrated model can cut its energy use by more than half. Offices/Businesses: Air conditioners are heavily used. High-efficiency inverter ACs can adjust their power consumption based on the room's temperature, saving massive amounts of energy compared to older models. Hotels & Restaurants: For commercial refrigerators, freezers, and laundry equipment.