Cold Swedish city uses solar heating in winter! How is it done?

William Atkins
Thursday, 26 July 2007 07:41

Science - Energy

"New Scientist" magazine reports that a few citizens of Sweden are heating water from sunlight in the summer by running it through pipes as part of rooftop solar heaters. Then, they store it and use it in the cold winter months.

Fifty homes in Anneberg, Sweden are geared up to reduce their traditional reliance of heating by almost 25%, maybe even more in the upcoming years.

For the last two years, the hot water produced in the summer by the rays of the Sun has been stored in pipes built within granite that is about 210 feet (65 meters) underground. The stone keeps the water hot until it is time to use it.

Then, when the cold temperatures of winter come, the hot water is pumped back to the surface and used for the heating of their homes.

As the granite becomes hotter over the next several years, possible savings could reach 70%, at least according to a study performed by a research team at Uppsala University (in Uppsala, Sweden).

The story is based on the New Scientist magazine, print issue 2613, July 21-27, 2007, page 25. An online version is also avaiable (for a subscription) at: Summer sun can provide winter heat.