Parabolic Trough

A parabolic trough is a type of solar thermal energy collector used in CSP plants (Concentrated Solar Power). The reflector, which concentrates the sunlight to a focal line or focal point, has a parabolic shape; these reflectors are tracked to the suns movement throughout the day to utilise the suns power to a maximum. Through the focal point of the parabola there runs a collector tube though which runs water, molten salts or thermo oil. Within this collector tube runs a metal absorber tube, through which runs the fluid media, This is usually embedded in an evacuated glass tube that reduces heat losses. A special high-temperature, resistive selective coating additionally reduces radiation heat losses. Sources : http://www.volker-quaschning.de/articles/fundamentals2/index.php http://en.wikipedia.org/wiki/Parabolic_trough