While photovoltaic solar panels are showing up on more and more rooftops, they are not necessarily the best solar power solution. The solar thermal collector can make use of all of the sunlight, unlike the PV solar panels, which can only use a fraction of the sunlight that hits them. The solar thermal collectors are used to collect heat that can then be used to boil water to make steam, which could then be used to drive a turbine to create electricity. Now researchers at Arizona State University, United States, have found a way to further increase the efficiency of these solar collectors. Robert Taylor, a graduate student in mechanical engineering, and his colleagues, have mixed nanoparticles into the heat-transfer oils normally used in solar thermal power plants. Using graphite nanoparticles, which are black and absorb light well, the team found the nanoparticles increased heat-collection efficiency by up to 10 percent. “We estimate that this could mean up to $3.5 million dollars per year more revenue for a 100 megawatt solar power plant,” Taylor said. Graphite nanoparticles are also cheap, at less than US$1 per gram. One hundred grams of these nanoparticles provide the same heat-collecting surface area as an entire football field. Taylor says: “It might also be possible to filter out nanoparticles of soot, which have similar absorbing potential, from coal power plants for use in solar systems. I think that idea is particularly attractive: using a pollutant to harvest clean, green solar energy.” The article can be viewed online at the link below.
http://www.physorg.com/news/2011-04-nanoparticles-solar-efficiency.html