Road rays heat homes
Rays from the sun falling on roads in a Dutch village have been used to heat local homes and commercial buildings.
Dutch civil engineering firm, Ooms Avenhorn Holding BV, has collected
solar energy from a 200-yard stretch of road and car park which it is using to heat a 70-unit four-story apartment building in Avenhorn.
A 160,000sq ft industrial business park in neighbouring town Hoorn is using heat stored during the summer from 36,000sq ft of pavement. Even the runways of a Dutch air force base are providing heat for its hanger.
Ooms' thermal energy system is the result of the firm's attempt to reduce road maintenance and costs. A criss-cross structure of flexible pipes are held in place by a grid and covered by asphalt, which magnifies the sun's thermal power. As water in the pipes is heated, it is pumped under ground to natural aquifers where it maintains a temperature of 68 F. The heated water can be stored and used months later to keep the road surface ice-free in winter and prolong road life.
The system can also pump cold water from a separate underground reservoir to cool buildings on hot days.
The firm found it had collected more solar energy during the summer than it needed to maintain the roads and began using it to heat buildings. The buildings had to be located near the tarmac to enable the heated water to be piped under the floor. The company made sure the water's temperature was high enough by passing it through an electric-driven heat pump.
The firm says the installation cost is double that of a gas-heated installation but the energy required is half and means a 50% carbon emission saving.
10 January 2008