Dissipation (Wastage) of Energy

Dissipation of Energy

(Energy Wastage)

What does this Thermal Image (Thermogram) Show?

Dissipation of Energy

- Explain ways of reducing unwanted energy transfer.

- Describe what affects the rate of cooling of a building.

- Understand that energy is dissipated.

KEY WORDS

conduction

energy dissipation/dissipation of energy

radiation

thermal conductivity

Open Ended

Can you list 5 examples of where energy is wasted in our modern, 21st century lives? Enter your answers below (2 mins)

Regenerative Braking

(Kinetic Energy Recovery System - KERS)

• First developed in 1967 by American Motors.

• Works on cars that have an all-electric or hybrid motor.

• Turns some of the car’s wasted kinetic energy (heat from the friction caused by braking) into electricity to charge its battery and boost efficiency.

• HOW CAN WE REDUCE WASTAGE?

• Clue: You have investigated this already previously

Multiple Select

If I wrap up an object with newpaper, what will it do?

• Keep the contents warm (eg fish and chips)

• Keep the contents cool (eg a tub of ice cream)

• It will make no difference

• It will heat the contents up

Open Ended

Why will the newspaper wrapping have this effect? Write a short answer below to describe what is going on

Energy loss at home

• Look at the diagram opposite

• Where do the biggest thermal losses occur?

• What can we do to reduce these?

Types of Home Insulation

• Fibreglass loft insulation reduces Convection losses. How?

• Underfloor insulation reduces heat loss through Conduction. How?

• Why are houses painted white (or light colours) in hot countries and dark in cold countries?

• Cavity Wall insulation (in the picture opposite) reduces heat loss by all 3 (convection, conduction AND radiation). How?