From My Bottom Step

“A Dutch businessman on holiday in the Highlands noticed how sheep liked to lie on roads warmed by the day’s sunshine. From that simple observation 15 years ago, a heating system has been developed that allows car parks and roads to act as solar panels, storing energy in aquifers – layers of water-bearing permeable rock”
(’Sheepish observation put businessman on road to hot invention‘; The Herald; 2006/06/22).

A solar energy collection ‘Road Energy System‘ built by the Ooms Avenhorn Holding BV Dutch civil engineering firm is heating homes and offices using heat from paved surfaces.

“A latticework of flexible plastic pipes, held in place by a plastic grid, is covered over by asphalt, which magnifies the sun’s thermal power. As cool water in the pipes is heated, it is pumped deep under the ground to natural aquifers where it maintains a fairly constant temperature of about 20C. The heated water can be retrieved months later to keep the road surface ice-free in winter. The same system pumps cold water from a separate subterranean reservoir to cool buildings on hot days.”

Links:
2007/12/29 – Toronto Star: Hot pavement tapped for heat…
2008/01/03 – TreeHugger: Dutch company siphoning heat…