How to stay warm

How to stay warm

If you visit upland areas of Britain– places like the mountains of Scotland, or Wales, or the Pennine Hills in northern England– you will see a lot of sheep. Many of the sheep are in places where there are no walls or hedges to keep them in their fields. So the sheep can wander where they like, over the hills, and of course on the roads as well. Sheep do not take much notice of cars. So, imagine you are driving along a little road in northern England. The sun is shining. You look at the beautiful views across the hills and the valleys. You turn a corner. And you find a flock of sheep on the road. The sheep look at you. You look at the sheep. You toot your car horn. The sheep look at you some more. Then slowly, they move and let you past.

The sheep particularly like the road in the evening, because it is warm. During the day, the sun shines on the road. If you try to walk across a sunny road in bare feet, you will know how hot the road can be. When evening comes, the road is a nice warm place for the sheep to go to sleep. And the sheep do not want to move, just because a car comes round the corner. Well, you would not like getting out of bed to let a car come past.

What is the point of this little story about sheep? It is that roads are very good at absorbing heat from the sun. A laboratory in England wants to see if it can use this fact to keep roads free of ice and snow in the winter. It wants to place pipes filled with water underneath the road. When the sun shines, the road will become hot and the water in the pipes will become hot too. A small pump will pump the hot water into a tank buried in the ground at the side of the road. The tank will be heavily insulated. That means that the heat will not be able to escape, and the water will stay warm for a long time. And on cold winter nights, the pump will pump the warm water back into the pipes underneath the road. The warm water will heat the road surface and keep it free of ice.

The scientists and technologists call this technology“ Interseasonal Heat Transfer”, or IHT. It is of course a very simple technology, but many people think that intelligent use of simple technology will be very important in the future. Climate change and the rising prices of fossil fuels like coal, gas and oil make it urgent to find new ways of doing things which will not damage the environment. If we can store heat from roads, car parks, airport runways, roofs, school playgrounds etc in summer, we could use the heat during the winter– not just for keeping roads free of ice, but for heating buildings and providing hot water.

In the last podcast, I asked you to imagine that you were very rich, and had lots of servants. Naturally, you have a tennis court and a swimming pool– probably you have three tennis courts and two swimming pools. How will you keep your swimming pools warm in winter? Easy– place pipes filled with water under the tennis courts to collect heat from the sun in summer. Store the hot water in insulated tanks and use it to heat the swimming pools in winter.