Hybrid Car – More Fun with Less Gas

Thermal flow in aluminum - Page 3

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Posted by Uncle Al on February 27, 2009, 3:57 am
Joesepi wrote:

Yer gonna solder aluminum?  Nice pictures.  Shiny black collector
surface is not clever.  You want it microporous on the scale of the
longest IR wavelength you want to absorb.  Black nickel solar absorber
coating electrodeposited on copper; Martin Black.


Engineer - to intentionally design with efficiency.  Degrees are
awarded in the discipline.  Find somebody who earned one.  If it's a
girl, keep looking until you find a boy.

Uncle Al
 (Toxic URL! Unsafe for children and most mammals)

Posted by Solar Mike (NZ) on February 27, 2009, 9:30 am

Last time I soldered 64 meters of copper foil fins to copper tubes,
process used approx 9 kg stick solder. Actually cost of using copper
foil instead of Al to make the fins is only $0 extra per sqm, plus
its much easier to bend the depression that sits on the riser tubes
than trying to bend Al and there are no dissimilar metal corrosion
issues, the foil is very thin 0.25mm but equivalent to using Al fins
twice the thickness.

High temp grease typically starts dripping at > 300 C so works well in
solar applications with AL fins

The pictures show a can of mat black spray paint used to paint the
aluminium fins.
Black chrome is not a DIY process.

Posted by amdx on February 27, 2009, 7:16 pm

This is a $00 DIY solar collect, I suspect it would be cost prohibitive to
get a
microporous surface on the aluminum for the DIYers.
 I didn't see any shiny black surface, it was flat black.
(yes, shiny is a relative term)

You could engineer a very efficient collector for $00 or build
2-$00 collectors that are only 60% as efficient and gather more energy.

Posted by Strange Creature on March 3, 2009, 6:40 pm


Posted by amdx on March 4, 2009, 5:27 pm

Strange Creature !

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