Solar Furnace Suns Concentration

> it a try) I've figured out that I'd need a dish of
diameter of 300
> feet, to concentrate 20 MW of power, which I believe
is around
> 15,000 suns.
>
> Now that's a whole lot of honking energy, and this
facility isn't
> floating in space, so I can't put the chamber oven
at the focal
> point of the dish - therefore, the energy has to be
transported to

You could put the chamber at the focal point, it would
not be
impossible.

>
> the oven, without melting the tunnel it's going
through. I'm

The tunnel would not get hot. You might not even
need a tunnel at
all.
All you need is for the chamber to have a window which
allows the light
beam to enter.

>
> envisioning the dish being on the roof and tracking
the sun during
> the lunar day. The oven would be in the smelting
facility, so the
> energy beam would need to be directed ~ 90 degrees
down into the
> tunnel at lunar sunrise and sunset.

I do not follow this at all. Why downwards ? Is
the furnace
underground ? Why is that ? It would make heat
rejection very
difficult.

I am afraid I do not understand your design.

But I do understand your requirements, so let me
propose a design for
you:-

Several small mirrors are a lot easier to steer than
one large one.
They are also cheaper to make.

The furnace sits on the lunar surface and has a
transparent window to
allow the light to enter.
An array of steerable parabolic mirrors each steers to
keep its focal
point trained on the furnace window.
The furnace and windows are placed so that the furnace
can be at the
focal point of all the mirrors.
If each mirror is, say one meter in diameter, then we
would need about
10,000 of them to achieve your desired power level.

The mirror array could be placed on the side of a
hill, in that case the
mirrors would be at different distaces from the
furnace, so each woudl
have a different focal length.