Solar Energy Conversion Process: Light and Heat

August 30, 2010 04:58 by Carbonica

The scientific struggle to increase the efficiency in which renewable energy is used and then reused has proven to be a daunting task. Large wind farms and fields of solar panels are commonly used to generate energy through solar radiation. Congruently, investors are having a troublesome time competing with traditional oil and electric suppliers.

 

Reducing our carbon footprint lies heavily on new technologies, and the efficiency of those technologies. For instance, Doug Band and the CGI (Clinton Global Initiative) have been working closely on a project to reduce fleet emissions in the San Francisco Bay Area by utilizing advanced route optimization software. In other related alternative energy news, companies like Ford have been implementing solar panels in their vehicles to promote the usage of solar radiation for hybrid vehicles.

 

Both of these are fantastic steps towards a more sustainable earth, but have we really reached the point where organizations and collaborative units like the CGI can see the ROI?

 

By definition, solar energy is radiant heat and light from the sun, which is harnessed by us to produce electricity. There are various forms of solar-powered devices, including wind, wave, hydroelectricity, and biomass – all costly and inefficient. Because of expensive resources, along with lessened efficiency, most of these devices cannot be utilized globally. But scientists out of Stanford have found a somewhat promising solution.

 

Typically, solar panels and/or secondary powered solar devices will capture light or heat, and convert it into electrical energy; but they’ve never been able to simultaneously use both, until now!

 

Photon Enhanced Thermionic Emission or PETE, simultaneously combines the heat and light from solar radiation to create electricity.  Traditional solar panels utilize photovoltaic technology, which is flawed in that it decreases in efficiency as temperature rises. This is an obvious problem, seeing as the sun produces both light and heat. The new process of PETE, actually increases efficiency of the panels as the heat index increases.

 

In a recent piece by Science Daily, Nick Melosh, a scientist at Stanford claims that this isn’t just a “slight tweak,” in the conversion process, but rather a major breakthrough in a new energy conversion. He goes on to mention that the materials required to make PETE are very affordable.

 

The intricacies of PETE aren’t too "sciency" for the simple-minded either – nearly 50 percent of lost energy is accountable to the silicon conductor having limited transparency in regards to the light entering in. Most of the unconverted energy then turns into heat; as the sun gets hotter, energy waste increases. The obvious solution to this problem was to find a way to harvest this unused heat energy. Melosh’s group discovered that by simply shelling a piece of semiconducting material with a layer of metal cesium, enabling the simultaneous usage of light and heat.

 

And the best part about PETE, is that it doesn’t reach maximum efficiency until the panels hit an excess of 200 degrees Celsius, which is extremely hot. Traditional solar panels reach somewhere around 100 degrees Celsius on a hot day in the sun. Accordingly, this allows PETE to be used in concentrators (i.e. parabolic dishes), which are typically used to power entire grids and communities

 

In these larger systems, any remaining heat waste can then be dumped back into existing thermal conversion systems, similar to those used in the Mojave Desert. PETE actually takes that unused heat, and later dumps it back into existing thermal conversion systems. Researchers state that by using PETE in these large solar concentrators, efficiency can increase by 55%.

 

By doubling the efficiency we’re at now with solar power, this would be a tremendous leap in green energy efforts. This will ultimately allow those invested to become a legitimate competitor of oil. Let’s hope that scientists at Stanford continue to keep up the good work!

This is a guest submission by Jack Lundee.

Jack Lundee was born in 1984 and is a regular contributor to everythingleft.wordpress weekly. He graduated from the Newhouse School of Communications and is now an IT expert and freelance writer on the environment and political science.


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