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.

My thinking is still constrained by how things are done on earth.
And I'm not an engineer, I'm from the finance/banking/VC industry. I
envisioned downwards because I had the furnace inside of a smelting
facility. I see a trade-off between an inside facility because it
allows easy worker access to the process (I'm assuming that the
process won't be completely automated) but then there is the issue
of an atmosphere to deal with. In a vacuum, I'm sure there are
advantages (no oxidation) but the workers have to be space suited if
they leave their control room.

On balance, which do you think is the best option for a facility?
Indoors or vacuum?

>
> 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.

Good point !

> The furnace sits on the lunar surface and has a
> transparent window to
> allow the light to enter.

Would the window be able to take the heat of the light beam?

> 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.

If the base is on the lunar equator, would that pose any problems
for multi-mirror placement?

Would each mirror have to been individually designed and fabricated
in relation to its placement on the hill because of the differing
focal lengths, thereby eliminating any benefits of mass production
and create calibration issues during initial placement and over the
course of the lunar day? I don't know.

Would larger mirrors, or one large mirror at the extreme of this
example, create fewer calibration and engineering issues, but create
a more formidible construction project? Design it once and build it.