Use of Asphalt Paved Surfaces For Solar Heat
vg30e writes "It seems that a company in the Netherlands has found a way to use asphalt paved surfaces as solar heat collectors. Flexible tubes under the surface of the road collect heat from asphalt pavement using water as the working liquid. The heated water is stored underground for later use in defrosting the road, or heating buildings. With all the miles of highway in the continental US, this might be a viable way of collecting massive amounts of thermal energy."
Physics professor Roland Winston, proposed this 25 years ago.
Its not uncommon for some very high end houses to do this during the summer and reverse the process (to keep the driveway ice/snow free) during the winter.