1. Making use of Energy Density Conduction
Keyword
Meaning
fluid
thermal
Convection current
Mobile electrons
Insulator
Energy saving measure
Density
Conduction
Making use of Energy
Describe how the following reduce energy loss from the house
How can we reduce our energy bills?
Resource
How?
Loft Insulation
Cavity wall insulation
Hot water jacket
Draught proofing
Floor insulation
Convection
Radiation
How do you calculate payback time?

2. Part of house
Insulated or not
Heat energy lost per second (w)
Cost of insulation
Payback time years
Expected annual saving £
Loft
not
4200
Fibre glass laid on loft floor
1500
800
200
Cavity wall
3000
 cavity
Insulated with foam
1300
1200 10
120
Door
wood
UPVC
1000 60
Windows
Single
Double
2400 96 25
A student wants to find the density of paraffin oil.
Explain how the student could calculate the density of oil.
She found out the mass of the oil was 60g and the volume was 75cm3.
Calculate the density of the paraffin.
Tidal water turbine
Wind turbine
Speed of water/ wind m/s 5 15
Density of water or air (kg/m3)
1000 1
Length of blade m 10 35
Area swept out by blade m2
314
3850
Power output at this speed MW
2.9
1.5
Use the information above to answer the following questions.
Calculate the difference in power output.
State 1 reason why water turbines have a bigger power output than wind turbines.
Other than having a larger power output, explain one other advantage that tidal water turbines have over wind turbines.
A semi detached house owner home is poorly insulated. The owner has £3200 available to spend on improving the home’s insulation. Information about each type of insulation is shown in the table at the top of the next section.
What is the payback time for the fibre glass insulation?
What is the expected annual saving for the UVPV door?
By how much does insulating the loft reduce heat energy lost?
By how much does installing cavity wall insulatio reduce heat energy lost?
Use information from the table to advise the home owner on how best to spend all of his budget. (QWC)
How much energy is lost through door?
How much energy is lost through walls?
How much energy is lost through the roof?
Explain how convection currents are set up in cavity walls with no insulation?
The family is advised to lower the temperature in the living room in the winter months to save money. Explain why this would increase the payback time.