sci.energy.hydrogen

Anthony Matonak wrote:
> J. Clarke wrote:
>> Morris Dovey wrote:
>>> I understand (I spent enough years in to be somewhat
>>> familiar with the requirements.) I would guess that what one
>>> would heat with the heliostat might be a metal with an
>>> appropriate melting point/heat capacity - then apply the heat as
>>> needed either to pull cylinders/ribbons/sheets.
>>
>> Pull? Silicon is either grown and then sawn or is deposited in
>> place. There's no "pulling".
>
> My understanding is that the heating processes used to refine
> silicon require very precise control of the heating over long
> durations. I don't believe direct solar heating would be able
> to do this very well.
>
> Evergreen solar uses a ribbon pulling method.
> /app/en/technology/item/48

When I think of "pulling" I think of processse like wire drawing in
which the material is deformed into the new shape, not lifted in
molten form by a process so gentle that it doesn't break surface
tension.

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--John
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