1. P1a 1.5 Heat transfer by design

2. Lesson Objectives To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer,

3. A thermogram shows the distribution of heat over the surface of a house. It highlights where heat is being lost. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer,

4. walls 36% floor 28% roof 20% windows 12% doors 4% Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer,

5. U-Values A measure of how well a building component, e.g. a wall, roof or a window, keeps heat inside a building. The higher the U-value the more heat flows through so a good U-value is a low one as you want to keep heat inside the building or outside depending on the climate you live in. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer,

6. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Find out the U-Value for the following and work out what is the best combination to reduce your household energy bills. Outer wall – 9” brick Outer wall – 11” block brick with cavity insulation Solid concrete floor Timber floor Flat 50mm insulated roof Pitched with felt, 50mm insulation Pitched with felt, 100mm insulation Wooden window frame, single glazed UPVC window frame, double glazed Wooden window frame, double glazed (Low E) http://www.diydata.com http://www.self-build.co.uk

7. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Find out the U-Value for the following and work out what is the best combination to reduce your household energy bills. Outer wall – 9” brick (2.2) Outer wall – 11” block brick with cavity insulation (0.6) Solid concrete floor (0.8) Timber floor (0.7) Flat 50mm insulated roof (0.7) Pitched with felt, 50mm insulation (0.6) Pitched with felt, 100mm insulation (0.3) Wooden window frame, single glazed (5.0) UPVC window frame, double glazed (2.9) Wooden window frame, double glazed (Low E) (1.7) http://www.diydata.com

8. A lot of heat energy can be lost through windows. Double glazing adds an extra pane of glass. The air trapped between the two panes acts as an insulator and reduces heat loss by: side-view of double glazing insulating layer of air Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Conduction MethodConductionConvectionRadiationCost Double Glazing YESNO HIGH

9. A lot of heat energy can be lost through windows. Double glazing adds an extra pane of glass. A vacuum can be created between the two panes to reduce heat loss by: side-view of double glazing insulating layer of air Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Conduction and Convection As there are NO particles MethodConductionConvectionRadiationCost Vacuum Glazing YES NOHIGH

10. The air trapped in the cavity acts as an insulator and reduces any heat loss due to: _____________ Most outside walls have an empty space between the two layers of bricks called a cavity. convection currents in the cavity Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Conduction

11. Plastic foam insulation can be pumped into the cavity to prevent ________ foam insulation prevents convection currents Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Conduction and Convection MethodConductionConvectionRadiationCost Cavity Insulation YES NOHIGH

12. The air warmed by radiators (and other heaters) is carried around a house by convection currents. heat loss loft insulation The house becomes heated but, if there is no roof insulation, the warm air continues to rise. The heat eventually escapes through the roof tiles by ______________. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Conduction MethodConductionConvectionRadiationCost Loft Insulation YES NOHIGH

13. Heat loss from a radiator can be reduced by A radiator produces infrared radiation. Some of this heat energy is absorbed by the wall that the radiator is attached to, and so the wall heats up. The foil prevents heat radiation from reaching the wall by reflecting it back into the room. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Placing a shiny sheet behind the radiator MethodConductionConvectionRadiationCost Radiator Panels NO YESLOW

14. Draught excluders are hairy or spongy strips that can be used to close the gaps around doors and windows. A draught is the movement of air due to __________ A lot of heat energy can be lost from a house due to draughts escaping through gaps under doors and around windows. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Convection MethodConductionConvectionRadiationCost Draft Excluders NoYESNOLow

15. A draught is the movement of air due Warm air rises and is carried up towards the windows in a house by convection currents. Fitting curtains and closing them can prevent draughts leaving a house and so reduce heat loss. This heat energy can escape through gaps around windows that are uncovered. In addition, curtains are opaque and so radiated heat does not pass through them. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Convection MethodConductionConvectionRadiationCost CurtainsNOYES LOW

16. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer,

17. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer,

18. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer,

19. walls 36% floor 28% roof 20% windows 12% doors 4% Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Heat lost fromPercentage Roof20 Windows12 Doors4 Walls36 Floor28

20. Keywords: To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer, Heat lost fromPercentage Roof20 Windows12 Doors4 Walls36 Floor28 20 + 12 + 4 +36 + 28 = 100 20% Roof 12% Windows 4% Doors 28% Floor 36% Walls

21. Are you now able to…. I still feel unsure. I need some more help to understand. I feel ok. I need to do some more work to check my understanding. I am happy and feel I understand and can explain the main points. To investigate factors that affect the rate of thermal energy transfer. To describe how thermal energy transfer is reduced in houses to keep them warm. To explain, in detail, how the design of a vacuum flask reduced thermal energy transfer,