h a l f b a k e r y
Breakfast of runners-up.
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
or get an account
[Edited: changed flat floor to hyperbolic] Probably much
less effective than a hyperbolic mirror
still this may be a cost effective solution for
concentrating light to a single point, with no moving
A [[two way mirror]] hyperbolic dome is set above a
mirror floor. The dome (as its
name applies) faces down.
[Edited: adding floor shape]. The floor consists of a
hyperbolic mirror which will reflect any light hitting it
upward and somewhat towards the higest part of the
Sunlight coming from any angle will enter the dome
passing through its semi transparent glass and hitting
the floor mirror.
It will then be reflected back to the inside part of the
dome which refelects it to the center of the hyperbola.
Since on most of the globe, the sun is always to one side
(North for Africa Australia and South Amerca, South for
the northern hemisphere) only half a dome is needed,
the sunlight would reach the floor directly without
passing through any glass, and would then be reflected
to the dome, which has an internal mirror
that is fully reflective, directing this light to focal point.
Since this is halfbakery, I expect people to come up with
improvements. No need to tell me how terrible this idea
is because of loss of light in each iteration (a. passing
through dome, b. reflecting from floor, c. reflecting
from inner side of dome.
I would appreciate, though, an estimate of loss from a
regular (not two way) good mirror, using the second
idea, or questions comaparing this to other solutions.
||If I understand correctly, in the first idea, light passes through the dome, where some is lost, but the angle is not changed, then reflects once off the flat mirror, then once off the inside of the dome. I don't see how this is geometrically different from inverting the dome and omitting the flat mirror, except that only (at most) 1/4 of the light makes it through.
||Too much hyperbole surrounding this idea.
||I'm correcting the idea. I looked at the problem
again. The light will need more than two bounces
before being concentrated. For example any light
hitting the floor too close to the dome
curcumferance would be reflected from the dome
at an obtuse angle, which would not return it to
the center, but rather several times around the
dome inside, until finally reaching the ground and
back from the dome to the focal point.
||So instead I'm adding a hyperbolic bottom mirror
which always sends the light directly upwards.
||Can anybody estimate what percentage of light and
energy a two way mirror absorbs when passing the
light through it?
||Same question for a regular mirror. How much energy
is typically absorbed by a mirror, and how much of
the light and other radiance returned?
||I finally found an expert on optics, who is working on
the idea (with some changes after he explained the
problems). I hope by 2012 to have a full-baked
product to show, started here at HB.
||Once you have the hyperbolic mirror, what good is the dome? The mirror will have a focal point and you can toast your marshmallows there. I suppose the dome would keep your mirror from filling up with rain and ducks.