Right now the two ways to generate electricity from the sun involve using photovoltaic cells or Concentrating Solar Power (CSP) technology. The former uses a solar cell to convert energy from light into electricity while the latter harnesses concentrated heat energy to generate steam to spin a turbine. However, Peter Bermel at the Massachusetts Institute of Technology and his colleagues may have found a third option: a suntrap.
In principle, heat from the sun can be used directly without steam or turbines. The only problem with generating electricity this way is that devices taking in the heat can rarely get warmer than boiling point when receiving unconcentrated sunlight. In order to be efficient, these devices need to attain temperatures as high as 700°C, which can only be done with a series of mirrors concentrating incoming solar radiation towards a central point.
However, Bermel’s new suntrap gets around many of these main issues while boasting a higher efficiency than both standard photovoltaic and CSP technology.
Basically, Bermel has proposed the utilization of a thin sheet of tungsten (which is heat-resistant material) manufactured in a specific way to harness heat energy. One surface faces the sun, and is covered in microscopic pits that trap incoming solar radiation. On the other side of the tungsten sheet is a solar cell made of indium gallium arsenide that selectively emits infra-red radiation at the frequency best absorbed by the cell. Over time, the trapped solar radiation gets amplified, thus allowing the tungsten to heat up to exceedingly high temperatures.
Basically, the suntrap is specifically designed to amplify incoming solar radiation and use it to generate electricity. The great thing about the new idea is that it converts 37% of sunlight into electricity, and is far less “messy” than CSP technology. The simplicity of the actual conversion process means that the suntrap would require very little attention once put in place.
Although Bermel is confident in the capabilities of the suntrap, the new technology must be tried out in the real world in order to confirm his theories.
What are your thoughts on the new suntrap? Do you think it will revolutionize the solar power industry?
Image CC licensed by Jalal Hameed Bhatti