Posted by tdv on February 27, 2005, 9:45 pm
Is it possible or efficient to use a fresnal lens for a solar focuser
instead of a parabolic?
Posted by Anthony Matonak on February 28, 2005, 5:55 am
Sure, it's possible and the efficiency difference really isn't
significant. You'll lose some percent by reflection or absorption
in the lens but reflectors lose some percent as well so you're
The big difference is that it's easier to bang out a parabolic
reflector out of something shiny than it is to make a fresnel
lens. This makes reflectors cheaper.
Posted by Nick Rouse on March 10, 2005, 3:12 pm
Do you mean a fresnel lens of fresnel reflector?
Mirrors are fine but large fresnel lenses are usually made of
plastic and some plastics are quite absorbant in the near infra-red
where there is quite a bit of solar energy