Hot roads in the winter

Ice and frost are major issues on winter roads in Northern Europe. This is especially true for roads with steep slopes, viaducts and bridges. Tests have been conducted on vulnerable road sections using waste heat from district heating plants to get rid of the ice. And now another step is being taken through a project initiated by researchers at Chalmers University of Technology, with financial support from the Swedish Transport Administration and the Norwegian Public Roads Administration.

The method is based on a ground-source heat pump system, which stores heat in the bedrock, applying the same principle as when heating a building. But as a road has a much greater surface area than a building, it is a matter of being able to supply enough energy for the ground-source heat.

The solution currently being tested involves utilising the solar radiation from the summer months. The heat on the surface of the road heats a liquid circulating in pipes, which are installed in the base course if it is an asphalt pavement. When the pipes pass the ground heat well, the surrounding rock is heated up. The energy is then stored in the rock and used during the winter by pumping the heat back to the road.

“Another positive effect is that the road is cooled down when you capture the heat during the summer, which can reduce the risk of deformation and bleeding,” says Jan-Erik Lundmark, Senior Advisor Road Maintenance, the Swedish Transport Administration.