Parabolic Trough Target Improvement
Morris Dovey
the target pipe at the focus of the parabolic trough shown at
http://www.iedu.com/DeSoto/Projects/Stirling/Heat.html
So I picked a few brains (most helpful were daestrom and frogwatcher) on
alt.solar.thermal (and had some discussion on alt.energy.homepower) and
came up with a way to bounce photons off the collector pipe surface more
than once before they had a chance to get away.
An experiment to test the idea was easy to put together. The results
were most satisfying and led me to conclude that reflection can be used
to produce near total absorption at the target pipe.
I thought the method might be patentable, and visited a local patent
attorney to start the patent search/filing process - which did turn up
an (expired) prior patent, so I won't be filing.
I'be cut and pasted some of the material I thought folks here might find
interesting (including photos of my simple experiment) from my notes for
the patent attorney into the web page at
http://www.iedu.com/DeSoto/Projects/Stirling/HTAbsorber/
and I have a batch of drawings and some calculation programs that I can
make available on other web pages if there's interest.
Many thanks to all who helped and encouraged!
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/
News
news:h7ioin$i94$1...@aioe.org...
Terrific stuff. :)
z
>
> http://www.iedu.com/DeSoto/Projects/Stirling/HTAbsorber/
>
> and I have a batch of drawings and some calculation programs that I can
> make available on other web pages if there's interest.
>
> Many thanks to all who helped and encouraged!
>
Thats really cool -- or hot I guess!
Man i'm tempted to build one just to screw around with. Looks like you
could easily adapt it to make a portable shishkabab griller :)
Grease on the reflective surface probably not agood idea though
nice job!
-zachary
Ken Maltby
"Morris Dovey" <mrd...@iedu.com> wrote in message
news:h7ioin$i94$1...@aioe.org...
Great post, just what I would hope for in these newsgroups!!
Brilliant research and exploitation of practical thinking, directly
applicable to efforts of those of us who follow the postings here.
I guess Usenet isn't quite dead yet!
Luck;
Ken
P.S. I'll have some questions and additional thoughts, later
after the Kudos die down.
Eric
Did you try heating a tank of water? At a given flow rate
what kind of temperature rise do you see from inlet to outlet?
How long does it take to heat, say, a 50 gallon water tank from
some starting temperature to some ending temperature?
What is the environment, outdoor temperature, general location etc.
I remember years ago me and another guy experimented with something similar,
it was unbelievable how fast and how hot the water got, we only had a small
amount of water but the outside temperature was a sunny 10F (In Maine,
winter time) and we managed to make steam in short order.
Please post more of your experimental results -
Thanks
Eric
Morris Dovey
I haven't made any of the tubing yet - I'm still scratching my head over
the problem of precise tube rotation (the equipment I have to do that
job lacks the necessary precision) and support of long tubing lengths,
which I don't expect to be a big problem but will depend on my solution
to the rotation problem.
My engines all operate on hot air - so I haven't even considered heating
water - and I think I can use this improvement to at least triple (and
possibly quadruple) the heat energy captured by the same reflector.
Most of what I do eventually appears on my web site - and these days I
seem to spend a fair amount of my time trying to help other people
who're working on parts of the project that I'd thought I'd have to do
all by myself...
...so, please feel welcome to take this and see how much of an
improvement you can produce in your water-heating project.
It was to support projects like yours that I posted the web page. :)
Frogwatch
Cool, cool, cool. I love seeing stuff like this. Maybe you could use
something like this as a concentrator for a solar still to desalinate
water. Lots of places have lots of sunshine and salt water and no
fresh water.
Frogwatch
prlax#mindspring.com
replace the # with @ for e-mail
Ahem A Rivet's Shot
Frogwatch <dbo...@mindspring.com> wrote:
> Cool, cool, cool. I love seeing stuff like this. Maybe you could use
> something like this as a concentrator for a solar still to desalinate
> water. Lots of places have lots of sunshine and salt water and no
> fresh water.
It doesn't take concentrated solar to desalinate water, the tricky
part is doing it sufficiently cheaply, efficiently and reliably without
introducing risks of infection or impurities getting into the desalinated
water.
--
Steve O'Hara-Smith | Directable Mirror Arrays
C:>WIN | A better way to focus the sun
The computer obeys and wins. | licences available see
You lose and Bill collects. | http://www.sohara.org/
Morris Dovey
> I've cut and pasted some of the material I thought folks here might find
> interesting (including photos of my simple experiment) from my notes for
> the patent attorney into the web page at
>
> http://www.iedu.com/DeSoto/Projects/Stirling/HTAbsorber/
>
> and I have a batch of drawings and some calculation programs that I can
> make available on other web pages if there's interest.
I think I'll need to organize this stuff better than I've done so far -
but I went ahead and added two "orphan" pages...
There's a page at
http://www.iedu.com/DeSoto/Projects/Stirling/HTAbsorber/Angles.html
with a program that, given an absorption rate, approximates absorber
efficiencies for various interior angles. Please note that that a
displayed absorber efficiency of 100% will always be the result of
rounding a (lesser) calculated value to fit the format width.
Once you've picked an internal angle, there's a second page at
http://www.iedu.com/DeSoto/Projects/Stirling/HTAbsorber/Grooves.html
with another program that, given the groove interior angle and depth,
diameter of the collector tube, and the angular width of the target area
on the tube, calculates the values needed to actually produce such an
absorber.
For MS users I've provided links on both pages to MS-DOS executables. To
download, right click on the link and select "Save target as" - then run
the program in an MS-DOS window.
Linux users can compile the C source with gcc and run it in an xterm (or
whatever).
Everyone else is on their own. :)
Have fun!
daestrom
"FIRE in the hole!!!" or would the grease be, "FIRE in the SLOT!!!" :-)
daestrom
daestrom
> Eric wrote:
<snip>
>
> I haven't made any of the tubing yet - I'm still scratching my head over
> the problem of precise tube rotation (the equipment I have to do that
> job lacks the necessary precision) and support of long tubing lengths,
> which I don't expect to be a big problem but will depend on my solution
> to the rotation problem.
>
> My engines all operate on hot air - so I haven't even considered heating
> water - and I think I can use this improvement to at least triple (and
> possibly quadruple) the heat energy captured by the same reflector.
>
> Most of what I do eventually appears on my web site - and these days I
> seem to spend a fair amount of my time trying to help other people
> who're working on parts of the project that I'd thought I'd have to do
> all by myself...
>
> ...so, please feel welcome to take this and see how much of an
> improvement you can produce in your water-heating project.
Great posts. Glad to see some real, informative and helpful stuff for a
change (the spam has been getting pretty bad).
Would love to see your engines when you get 'em going.
daestrom
Morris Dovey
> Would love to see your engines when you get 'em going.
I don't have any way to capture video, but you can see some of other
people's in operation at
http://www.iedu.com/DeSoto/Projects/Stirling/Elsewhere/
Eric
Its people like you who will give the common man "a leg up" on lowering
their energy bills. If i had money i would offer to fund your
experiments in a more formal setting, but. . . sorry, I'm just a working
stiff like most people.
Keep on keepin' on
Eric