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?

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.