Uh, John?
Beware I don't puncture *you* after removing what remains of you from
the freezer.
[I wonder what kind of solar collector you can make out of an old
vampire? Not much of anything, I'll wager]
--- In OliveStarlightOrchestra_at_yahoogroups.com, "tschibasch"
<tschibasch_at_y...> wrote:
> Well, I am glad that you at least were able to understand it!
>
> There was enough jargon in Debbie's paragraph that I had to read it
> two or three times before I got it. To render it into simpler
English
> for the rest of you folks, what Debbie is saying is: When removing
> the coke bottle from the freezer, don't puncture it.
>
> ;-)
>
> John
>
>
>
> --- In OliveStarlightOrchestra_at_yahoogroups.com, David Coons
> <yahoo_at_a...> wrote:
> > Debbie's got some good ideas there. Our hydronic
> > heating system has copper tubing and even that slitted
> > black foam insulation material you push on to keep
> > the heat in. We've also done her papier-mache
> > balloon trick to make concave spherical surfaces
> > and it works pretty well. Note that a spherical
> > surface very closely approximates a parabola for
> > small off-axis angles, particularly if the focus
> > is large piece of copper.
> >
> > I believe a parabolic surface can actually be formed
> > by starting with a crude near-parabolic bowl, filling
> > it part way with a hardening polymer, then spinning
> > it 'till it dries. Then you have to mirror-coat it.
> > But it's probably something more easily purchased from
> > a stock house like Edmund Scientific, which is now:
> > http://www.edsci.com
> > They also sell fresnel lenses in various sizes, which
> > also concentrate solar energy quite well and are
> > damned more fun to play with, like at Cassini parties,
> > where you can watch small children sear the flesh of
> > their siblings. JT might use them for lighting cigars,
> > probably even by moonlight. :)
> >
> > The more efficient large solar concentrator arrays are
> > actually rows of parabolic troughs, with motorized sun
> > tracking elevation control and blackened pipes running
> > along the focus line. JT might use these for lighting
> > a bunch of cigars at once for *his* next party..
> >
> > Then there's always google.
> >
> > dc
> >
> > Georgie Hinklemyer wrote:
> > > P.S. Keep the copper tubing short, to minimize heat loss.
> > >
> > > --- In OliveStarlightOrchestra_at_yahoogroups.com, "Georgie
> Hinklemyer"
> > > <samoolives_at_y...> wrote:
> > >
> > >>Mylar works great as a surface coating. Or any other silvered
> > >>sheeting. Tinfoil is lots cheaper and easier, but collects
> wrinkles
> > >>like you wouldn't believe.
> > >>Really small egg shape: use a plastic lady's "L'Eggs" Egg. They
> > >
> > > make
> > >
> > >>nice parabolic surfaces.
> > >>Medium-sized egg shape: try blowing up a balloon, tape the knot
> down
> > >>VERY flat, and papier-mache it. Use the knot end as the bottom
> of
> > >
> > > the
> > >
> > >>mirror. Punching-bag balloons get to be about 2 feet across, if
> > >>you're lucky.
> > >>Smaller egg shape, already mirrored: a mylar balloon. Papier-
> mache
> > >
> > > it
> > >
> > >>and the inside's already silvered. Might not be a steep enough
> > >>parabola, though.
> > >>Do you know how to calculate the focus of a parabola?
> > >>--Debbie
> > >>
> > >--- In OliveStarlightOrchestra_at_yahoogroups.com, "Richard Conner"
> > >> <rkc_at_p...> wrote:
> > >
> > >>> > I'm looking into experimenting creating a sort of
> > >>> > hemispherical solar
> > >>> > concentrator. Perhaps some of you out there may have some
> > >>> words of
> > >>> > wisdom or ideas for me...
> > >>> >
> > >>> > Looking something like:
> > >>> >
> > >>> > | o |
> > >>> > \ |=/=== b
> > >>> > -|-
> > >>> > |
> > >>> > a
> > >>> > 1. Lightweight plastic(?) hemisphere - possibly some sort
> > >>> > of sphere
> > >>> > that might be cut in half.
> > >>> > 2. Some form of reflective coating?
> > >>> > 3. Small copper ball (o) attached to copper tube/wire (o-a)
> > >>> > dropping thru hemisphere.
> > >>> > 4. Clear plastic(?) tubing(?) (a-o-b)
> > >>> >
> > >>> > Experiment is to heat water in tube (o-a) to cause
> thermosyphoning
> > >>> > from cooler water below (a) to be heated and flow out thru
> (b).
> > >>> >
> > >>> > Any suggestions for parts/information/etc much appreciated.
> > >>> >
> > >>> > -Richard
Received on 2004-06-14 00:25:33