alt Hacker NewsCan infrared energy be reflected like light? What would a good reflector be? (THEORETICALLY) Would a parabolic dish over this facility be able to focus the heat to a single point and, if so, what would the temp be? Is it additive? Like X joules of Y degrees over Z square meters focused down to 1 Sq cm?
Yes. Metal. No.
You want to read about "conservation of etendue" for a technical explanation. For an easier explanation, look for xkcd's excellent "Fire from Moonlight".