“Lots of Energy in the Street” – Dutch Firm Produces Solar and Geothermal System Underneath

Ever run your car over the heating system of an office
building? If you’ve been to Scharwoude
in the Netherlands, you may have – but you would not have known it. As reported in this week’s Economist magazine, Dutch company Ooms Avenhorn
Group has developed a heating and cooling system that relies on asphalt roadways
and underlying aquifers. The company’s
offices in Scharwoude are heated and cooled using this method. An excerpt of the article:

"The heat-collector itself is a circuit of connected water pipes. Most of
them run from one side of the street to the other, just under the asphalt
layer. Some, however, dive deep into the ground. In summer, when the surface of
the street gets hot, water pumped through the pipes picks up this heat and
takes it underground through one of the diving pipes. About 100 metres down
lies a natural aquifer into which a series of heat exchangers have been built.
The hot water from the street runs through them, warming the groundwater,
before returning to the surface via another pipe. The aquifer is thus used as a
heat store.

In winter, the circuit is changed slightly. Water is pumped through the heat
exchangers to pick up the heat that was stored during summer. This water goes
into the Ooms building and is used to warm it up. The water is then pumped
under the asphalt, and the residual heat it carries helps to keep the road free
of snow and ice. By now the water has been cooled to near freezing point, and
it is once again sent underground—this time through a different pipe, to a
second aquifer. Here, another set of heat exchangers is used to cool the
groundwater. This store of cold water is then used in summer to keep the Ooms
building cool.

The result is cheap heating in winter and cheap cooling in summer. And there
is a bonus. Summer heating softens asphalt, making it easier for heavy traffic
to damage the road surface. Dr de Bondt’s system not only saves electricity,
but also saves the road. Expect to see more examples of it, in other countries,

Janet Attarian (project manager of Chicago’s new
to use alleys more productively) asked in a recent New York Times
, “can you make alleys do more for you?” Converting streets into energy collection and
storage facilities may just qualify.

Why is this important? It could serve several significant ends:

 • Generating and storing energy through this combined
solar/geothermal method provides a financial hedge against significant price
fluctuations of conventional alternatives such as natural gas.

• Moving some infrastructure for heating and cooling under
the street may increase the square footage available for the primary building
purpose, be it housing, manufacturing, office or retail.

• Making streets and alleys “work for you” as energy
infrastructure increases the intensity of use of urban land and bolsters tax
base, providing support for the private
and public efforts required for regions to differentiate

Photo:  Courtesy of Flickr.