Roadways (Asphalt) can be Used To Harness Solar Energy

Thu, Nov 18, 2010

Renewable Power, Solar Power

Roadways (Asphalt) can be Used To Harness Solar Energy

A recent experiment was conducted by Professor K. Wayne Lee and a URI student. Andrew Correia (student) evaluated the amount of solar energy that is derived from a patch of asphalt.

The roadways have always been a determinant of city temperature. Heat radiation on asphalt is often a major reason why the temperature is elevated in urban regions in comparison to rural areas.

A team of research engineers teamed up at the University of Rhode Island to examine new innovate ways to harness solar energy to power streetlights, heat buildings, melt ice and other ancillary purposes.

There are large pavements covered with asphalt. These roads absorb a significant amount of heat during the summer. K. Wayne Lee, URI professor of civil and environmental engineering as well as the leader of this joint project says that the temperature on an asphalted road goes beyond 140 degrees. If it would be plausible to use this energy, it could significantly reduce our dependency on fossil fuels.

The team from URI has already discovered four potential ways to do so. They are now extending their research to design simple to complex architectures, which will make solar asphalt energy a reality.

The easiest way, would be to integrate flexible photovoltaic cells to barriers that divide highways in Jersey. This energy could be used to illuminate road signs and to power streetlights. It could also be possible to embed photovoltaic cells in roadway barriers as well as adjacent rumble strips in Jersey.

Lee says that the technology can be embedded today itself, as the necessary technology is already available. Besides, the latest generation solar cells are highly flexible. It would be easy to fix them, irrespective of the angle of the sun. They can constantly produce electricity. Currently, a pilot program has been established. The lamps that are just outside Bliss Hall, on the campus is powered through this technology.

A second method to harvest solar thermal energy from asphalt is to install water pipes just under the asphalt. The sun will thereafter heat the water. The heated water could be used to heat the asphalt to melt ice that accumulates on the surface. This could significantly reduce the need for road salts. Otherwise, the water could be piped to buildings where hot water is needed, to act like a geothermal heat pump. The hot water could even be used to spin a steam turbine to produce electricity on a small scale.

A prototype of the pipe system has been constructed by Andrew Correia, Graduate student, at URI laboratory. The aim is to determine how effective the system will be, in reality. The project is being funded by Korea Institute for Construction Technology. The prototype is being scrutinized on various asphalts mixed and with different pipe systems. Andrew is trying to prove how this technology can work on conventional pavements.

A very important feature of asphalt is its ability to maintain heat. This means that even after sunset, asphalts will maintain a high temperature in the water pipes. The tests performed by Correia demonstrated that the water can at times turned into an even higher temperature than the asphalt.

The third option is to generate a small amount of electricity via a thermo-electric effect. Two different types of semiconductors would be needed to join cold and hot circuit. This could produce a usable amount of power.

Sze Yang, URI chemistry Professor thinks that it would be possible to integrate termo-electric materials on various depths of the roadway – some could be placed in the shade and others in sunny locations. The disparity (difference) in temperature would produce the electricity power.

Now imagine if several of these systems were installed on the roadway. It would be enough to defrost and provide some extra electricity as well. Sze Yang also suggested that organic polymeric semiconductors that have been developed at his laboratory should be used instead of conventional semiconductors. These new innovative semiconductors are cheaper and more flexible.

Yang, does indeed highlight that this is rather a futuristic idea. Currently, no commercial devises is available on the market to generate electricity in this way. However, researches in the laboratory have confirmed its feasibility. Additional, studies in the field might soon revolutionize the idea and make it a future reality.
The fourth and the most utopian idea that was brought-up by URI team was to substitute asphalted roadways with solid electronic blocks having photovoltaic cells, sensors and led lights. These blocks would have an embedded technology which could illuminate the road lanes, provide warnings when road maintenance would be needed and definitely produce electricity.

Lee even mentioned that the technology to realize this concept exists. However, the cost is lucratively high. For instance, a group in Idaho, constructed a driveway using a model of these blocks which cost around $100,000. According to Lee, corporate parking areas might be the first to integrate this type of technology. The cost might thereafter start to fall as it becomes more common.

The transportation industry will have difficulties to swallow this new idea. However, it is time for highways to advance. The conventional asphalt roads have been used for over 100 years. Lee says that “pretty soon it will be time for a change.”

Source: Phys Org

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RPN's contributed to this report.

Professional freelancer in Green Technology and Scientific Development. Educational background in the field of Human Resources Management.

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