1. M. Manser Invicta Grammar School GCSE PHYSICS MODULE P1: ENERGY FOR THE HOME Item P1b: Keeping Homes Warm At the start of this presentation, you will review heat loss by radiation. Then you will examine some thermograms showing where energy is lost from houses and some other objects. Towards the end of the presentation, you will need to identify ways of preventing heat loss around the home. You will see several incomplete slides where you will need to carry out research in order to finish the presentation yourself; and there is a homework assignment at the end.

2. M. Manser Invicta Grammar School Heat loss by radiation All warm objects radiate heat energy in the form of infrared waves. The higher the object’s temperature, the more IR waves it will emit. A dull, black object (when hot) will radiate its energy away very quickly. Whereas a hot object will retain its heat energy better if it has a silvery surface. IR waves are very similar to light waves, but they are invisible to the human eye. Special cameras must be used to obtain infrared images. The pictures are called “thermograms” since they show hot regions and cold regions very clearly.

3. M. Manser Invicta Grammar School Some thermograms Generally, we lose most of our heat from our heads. Look at the colour scale that was used to determine hot and cool areas. This technique is used in medicine to look for circulation problems.

4. M. Manser Invicta Grammar School Look carefully at the scale, this computer has used slightly different colours in their temperature scale. By carefully comparing the heat distribution patterns, a vet can spot potential problems. Can you? Heat is lost from the blood as it circulates. Cold spots suggest diminished blood flow in that area.

5. M. Manser Invicta Grammar School Thermogram of Buckingham Palace. From which area is most heat being lost?

6. M. Manser Invicta Grammar School Thermogram of an aeroplane From which area is most heat being lost? Why would the body of the plane be designed in this way?

7. M. Manser Invicta Grammar School Thermogram of an elephant Which area is the coolest? An elephant’s ears are large and thin. The blood flowing through the veins, arteries and capillaries can be cooled easily. When the temperature of the environment rises, the elephant flaps its ears to cool the blood flowing through them. This then circulates through the rest of the body to cool the animal down.

8. M. Manser Invicta Grammar School Thermograms of houses This picture shows two houses. The one towards the back is a much older house. Which house is allowing more thermal energy losses? How are houses today constructed to reduce heat losses? The older house is losing large amounts of heat through the walls, windows and the chimney!

9. M. Manser Invicta Grammar School This thermogram suggests that the older house may have had only a single external wall, or perhaps the newer house had cavity wall insulation. The roof of the older house may have had loft insulation. This can be achieved with fibreglass or mineral wool. This method of insulation is relatively cheap. The newer house has had triple glazed windows installed. This method of insulation is quite expensive, but will save you money in the long run.

10. M. Manser Invicta Grammar School Another thermogram of two apartment blocks. In which building will the residents be paying larger bills for heating? Which building has had double glazed windows installed? Do all buildings use the same type of fuel for heating? The building in the bottom picture The residents of the building in the top picture will be paying more to heat their apartments. Too much of the heat produced inside is being lost through the windows. Homes can be heated by electrical methods which may rely on fossil fuels. A minority of homes may receive electricity produced by renewable resources. Also, most homes have radiators which use water heated by natural gas.

11. M. Manser Invicta Grammar School Examples of energy saving methods and strategies. (ie different insulating methods….can do task P1b)

12. M. Manser Invicta Grammar School Designing a house to minimise thermal energy losses.

13. M. Manser Invicta Grammar School Cost Effectiveness! Method Cost to install (£) Annual savings (£) Payback time (yr)

14. M. Manser Invicta Grammar School Homework! You have one week to carry out a survey. You may do this individually, or in groups (no larger than 4 students) How are homes heated in the area in which you live. Survey at least 15 homes and present your results in a pie-chart or bar graph. Use a sheet of A4 paper to prepare a report of your findings. Include a map of England/ Kent/ Maidstone to show the area where the survey took place. Include information on costs in this area. This may vary depending on the energy company (eg. Seeboard or British gas), and type of fuel (eg. electricity units, gas, wood)