Reflective materials for solar arrays
Thursday, October 9th, 2008
Hi Jeff
Has anyone tried to set up solar arrays with supporting reflective materials around them?
I am thinking of those sun blankets they used to sell in the 80s that looked like tin foil–they bounced back the sun’s rays onto bodies and increased sun exposure and accelerated tanning. Do you think a surround like this could bounce back rays onto solar panels and increase their efficiency? Do you think this sort of solar panel support system would be effective and cost efficient?
Also, rather than setting up solar panels on individual homes, is it possible to set up community solar arrays? Is there theoretically any physical or technical barrier to collecting energy in this fashion and then sending it out to various nearby home sites? I guess you would need a lot of panels as your article mentions, but as the technology improves, perhaps they could go from supplying homes with 20-30% of their power needs up to greater percentages. It may be easier to organize it this way, rather than putting the burden on each individual homeowner to finance and build their own mini solar power plant–forcing them to sport the lovely (not!) solar panels on their home roofs and deal with shadows from trees and surrounding objects. Would it be difficult to set up a solar system that supplemented and interfaced with traditional electric power for a group of nearby homes?
Thank you. Looking forward to your response
Sincerely,
Mary Morrissey
Mary:
Adding reflectors has been tried since the solar module was first invented. Several large utility-size solar power demonstration projects in the late 1970’s used reflectors on the solar modules. There are a few problems that makes this impractical on a small scale system.
If you are reflecting part of the surrounding solar energy that would be lost back onto the modules, this tends to cause much higher temperatures on the modules so you get more discoloration and shorter life since the higher the temperature, the lower the efficiency of any solar electric module. They have made special very high temperature modules that have cooling coils behind them to take way the heat and they are made of materials that can take mirrored reflectors to really concentrate the solar energy onto them. However, any type of reflector, mirror, or concentrating lens requires a very clean surface and a clear sky since clouds covering the sun stops all focusing of these devices. This means the only places they work well is out in the desert with strong solar energy, no clouds, nothing to dirty up the reflectors, and a maintenance staff working full time to make adjustments, repairs, and clean the reflectors.
Yes, there have been a few attempts to do a community size solar system and I think you will see more. So far, most of these have been on islands and isolated areas where everyone was willing to live a low energy lifestyle, i.e., no air conditioning or heating appliances, and limited power requirements. There are some tax advantages for someone setting this up, but there are very high startup costs and you could only make it work in areas where regular utility power is not available at any price.
Hope this helps,
Jeff Yago
