October 21, 2010
Over a period of many months, NREL conducted a number of optical tests on the new, lightweight SkyTrough, a parabolic trough collector developed by SkyFuel. NREL engineers worked with SkyFuel engineers to identify areas of the reflector in need of attention. After a series of improvements, test results on NREL’s Optical Efficiency Test Loop, combined with heat loss results from our receiver test lab showed that the new design has a high performance comparable to that of the best glass mirror modules.
Utility-scale parabolic trough solar concentrators harness the sun’s energy to make steam for electricity generation. The thermal efficiency of the trough is the percent of available sunlight that is converted into heat and available to generate electricity. This efficiency rating is used to predict the performance of a given parabolic trough and compare competing technologies.
After combining the results of optical and heat loss tests, NREL researchers found that the SkyTrough’s thermal efficiency is more than 73%, meaning that nearly three quarters of the solar radiation striking the trough surface is converted into thermal energy. This means that the lighter-weight design, which should result in considerable cost savings, doesn’t sacrifice when it comes to performance.
The SkyTrough employs several advanced design elements. It uses the patented ReflecTech Mirror Film, developed jointly by SkyFuel and NREL. The special film is used in place of the traditional fragile, heavy glass mirrors. The film is incorporated into a large, continuous reflector, which eliminates the gaps and mounting complications associated with separate, small mirror modules.
SkyFuel expects that the results of their collaboration with NREL will help make concentrating solar power more economical and thus more attractive to utilities and their customers.