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11 Sep, 2008

Asphalt as an energy producer

Posted by: Skylar In: pavement

A while ago, I came across an article that made me realize the environmental impacts of hot mix asphalt.  Now, researchers from the Worcester Polytechnic Institute are looking into a way to make an old technology more eco-friendly.

Everyone knows how hot asphalt can get sitting out in the sun all day.  Why not harness some of the solar radiation that is absorbed by asphalt and use it as an energy source?  I think it’s a great idea, and I’m quite surprised no one has ever experimented with this before.

The idea is simple—install piping below the asphalt surface and charge it with a low-boiling-point fluid that is cooler than the pavement. That reduces pavement temperature while heating the fluid, which then can be used for heating through a heat exchanger or for power using a thermal-electric generator. Mallick estimates the system will cost about $20-to-$50 per sq meter installed and says a 2,025-sq-m slab could generate up to 800 kWh per day in a New England summer. Sunnier areas can produce more.

Of course, civil engineers can see some problems with this technology.  How would the system deal with freeze-thaw? Asphalt cracking?  And most importantly, how would it affect the overall structural integrity of the pavement?

Now, none of these questions are unanswerable.  In fact, the article suggests that Europe has already piloted the concept in a couple places:

there have been some studies in Europe and Japan. “Now, after our work, we’ve identified the important factors and we know what doesn’t work,” he says. Japanese re-searchers have pumped river water through pavement as a way to reduce temperatures and heat deformation, and a Netherlands firm, Ooms Avenhorn Groep bv, has used the process to heat buildings and potentially to heat and cool roads, notes Mallick. A spokesperson for the National Asphalt Pavement Association, Lanham, Md., says it has not heard of any U.S. studies other than WPI.

Solar Asphalt System Provides Green-Heat Energy Source

So, readers – do you think it’s just another hyped concept, or a serious possibility for the future?

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