Energy

Programme Outline

The programme is in three parts. In the first part we visit a Georgian house. We see how inefficient the house is, but also the ingenious methods our predecessors had for keeping warm. In the second part, we go to Oxford to visit a modern, purpose-built, energy-efficient house. In the third part, we travel to Greece to see how people keep cool, and discover that evaporation has an important part to play.

00.00 - 00.30 Keeping warm, keeping cool

Jason (as Steve Gazebo) is selling double glazing. We are introduced to the infrared camera as a way of seeing hot and cold regions. It shows that his face is warm but his ears are cold.

00.30 - 01.20 A house in infrared

An infrared shot of a nineteenth-century house shows how the windows are wasting energy. Lots of hot air can be seen escaping.

01.20 - 02.16 The Georgian house

Dan Cruickshank leads an authentic Georgian lifestyle in a house parts of which date back to the seventeenth century. The house is cold, but he wears his hat indoors. The furniture is designed to stop people getting cold: for example, the wings on the chairs keep away the draughts.

02.16 - 02.30 Heat losses

However, as well as heating his house, he is heating the street through convection, conduction and radiation.

02.30 - 02.54 Conduction demonstration

Using the infrared camera, we see thermal conduction along a hot poker. The energy is transferred from the tip to the handle.

02.54 - 03.46 Conductors and insulators

Glass is a poor conductor, but there are a lot of windows. Their large area means that a lot of energy is conducted through the windows to the street. Using the infrared camera we see a demonstration of conduction in wood, glass, steel and copper.

03.46 - 04.36 Convection

Hot air rises from candles and turns the fan blades on a Victorian table decoration. We see an infrared sequence of hot air rising above the radiator.

04.36 - 05.16 Shutters

The house's shutters are an old form of double glazing. The warm air of the room doesn't get in contact with the cold glass. The air trapped between the shutters and the glass is a good insulator.

05.16 - 06.40 Radiation

We see an old-fashioned portable radiator. It is a cannon ball that has been heated in the fire. It has a high thermal mass (heat capacity) and stays warm for a long time. Also, the fire downstairs has a lot of of ironwork that heats up and stays warm, radiating into the room.

Despite Jason's best efforts, Dan doesn't want to install UPVC double glazing.

06.40 - 07.36 An energy-efficient house

Jason (as Tony Balero, estate agent) is visiting an energy-efficient house in Oxford.

07.36 - 08.08 A special house in infrared

The infrared image of the outside of the house shows that hardly any heat is escaping compared with a more ordinary house next door.

08.08 - 09.35 The stove

The stove has a high thermal mass - like the ironwork of the Georgian fire. The concrete keeps the house warm even after the fire has gone out.

The hot air from around the stove is guided by a skirt so that it keeps the other rooms warm through convection currents.

09.35 - 10.30 Highly insulated walls

The walls have three layers, each with a different function:concrete to store the heat, then a fibre layer for insulation, then normal bricks. The roof also has a thick layer of fibre wool.

10.30 - 12.00 Triple glazing

The windows are triple glazed! They let sunlight in to heat up the house, but they trap air, which is a good insulator.

12.00 - 13.20 Using the sun

The roof has 38 solar panels, which generate a surplus of electricity. Also, the 'sun space' helps to heat the house directly. The space is angled so that it catches the sun all day in winter.

13.20 - 14.30 The greenhouse effect

The sun trap works like a greenhouse. The sunlight streams in and warms the internal surfaces. These heat the air around them, which rises, but can't escape.

14.30 - 16.20 Staying cool in the sun

If you want to stay cool in the sun, then wear white and use a white parasol. White reflects light and infrared waves. The Sun's energy reaches the Earth as electromagnetic waves, including visible light, infrared and ultraviolet. It is the infrared radiation that warms us up. Ultraviolet causes tanning (and sometimes skin cancer).

16.20 - 16.55 Reflecting rays

A white umbrella reflects more energy than a black umbrella. We see this demonstrated using the infrared camera.

Mediterranean countries often have white painted houses to reflect the sun's rays and stop them overheating.

16.55 - end Cooling by evaporation

The methods of keeping wine cool and sweating to stay cool both rely on evaporation. The more energetic water molecules escape, thus reducing the average kinetic energy of those left behind. So the liquid temperature drops. A porous pot can be used to cool wine because it has a moist surface from which water evaporates.