Now here’s something interesting - a Dutch company has created a way to take heat from the asphalt in roads and parking lots to heat homes and offices.

Projects include solar energy collected from a 200-yard stretch of road and a small parking lot helping to heat a 70-unit four-story apartment building. And all that under normally cloudy Dutch skies, with only a few days a year of truly sweltering temperatures.

This ‘Road Energy System’ consists of a layer of asphalt concrete that has a closed system of pipes running through it. The pipes are connected to underground aquifers (water-bearing sand). In summer the sun heats the asphalt concrete pavement, which in turn raises the temperature of the water in the pipes. The water is then transported to the heat source area, where it is stored for several months. As soon as autumn arrives, the system brings the warm water to the surface, where a heat pump raises its temperature to a level suitable for low temperature heating systems. The surplus thermal energy is used to keep the temperature of the asphalt concrete above freezing point. The asphalt concrete cools the water to the point where it can eventually flow to the cold source. In summer the process is reversed. Water is pumped up from the cold source and used to cool buildings. This warms the water, which then moves through the asphalt collector again, is heated further by the sun and then injected into the heat source in the ground.