Solar Thermal Research Program

Solar thermal energy systems use concentrated radiation to provide thermal or electrical energy from a few kilowatts to hundreds of megawatts, to produce high temperatures without combustion or mechanical conversion, to supplement or supplant basic heat sources in existing industrial and utility plants. They can also be integrated with thermal energy storage systems to deliver energy afterdaylight hours. The concentrated solar flux can be beneficially used for materials treatment or to affect chemical reactions directly. Present solar thermal technology concentrates the solar flux by means of tracking mirrors or lenses onto a receiver, where the solar energy is absorbed as heat in a working fluid and converted into electricity or incorporated into products as process heat.Receiver temperature can range from 100 degrees C in low temperature troughs to over 1500 degrees C in dish and central receiver systems, although present-day experience is largely in the 100 degrees - 600 degrees C temperature range. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line focus optics to concentrate sunlight.Current central receiver systems use a field of heliostats (two-axis tracking mirrors) to focus the sun's radiant energy onto a receiver. Trough and bowl are reflectors that concentrate sunlight onto linear receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system.