Ever stand barefoot on pavement in the middle of the summer? If you have, you probably didn’t stay there long. That’s because asphalt and tarmac absorb the sun’s rays, storing heat in the ground, and on the hottest days, one can actually see the heat radiating from the streets. A Dutch company thought that heat would be best captured and saved for the winter.
Ooms Avenhorn Holding AV first conceived this idea 10 years ago, and it intended the stored heat to keep the roads warm in the winter when ice and snow were inevitable. Ooms installed the system in Avenhorn, a village in northern Holland. However, the company found it had leftover heat that the roads didn’t need.
“We found we were gathering more energy in summer than we needed, so we asked a building contractor what we can do with the extra energy,” said Lex Van Zaane, Ooms’ commercial manager. The contractor told Ooms to construct buildings near the road, and pipe hot water under the floor.
The system works with a grid of flexible, plastic pipes, which is filled with water and then laid down before the road is constructed. As the water is heated through the road, it is pumped underground to aquifers that keep the temperature at 68°F. The heated water can return during the winter to keep the roads warm enough to prevent ice from forming. The extra heat Ooms’ discovered can then be pumped under the nearby buildings, reducing the dependence on energy from the utility.
The water, however, isn’t hot enough to heat the building on its own. In addition to the road-heating system, Ooms installed an electric heat pump to boost the water’s temperature enough to be effective. According to Van Zaane, the cost of installation is almost double compared to that of a normal heating utility installation; however, the buildings benefit from requiring less energy that the utility would otherwise need to generate, meaning the owners save on electricity and carbon emissions.
Currently, the system collects the heat from 200 yards of road and a small parking lot. It heats a 70-unit, four-story apartment complex. Ooms also has installed similar systems in an industrial park in the nearby city of Hoorn. It collects from 36,000 square feet of pavement. In addition, the runways of a Dutch air force base heat a hangar.
And all of this is working technology in a part of the world that experiences normally cloudy skies and mild temperatures.