parabolic mirrors
Don Kulha
In article <wood.281....@pop.service.ohio-state.edu>,
wood...@pop.service.ohio-state.edu (Will Wood) wrote:
> Hi all,
>
> Does anyone have any ideas on how to make a parabolic mirror about 1.5 by
> 5 feet? I would like to use the cheapest materials yet have it still be
> effective. I'm hoping to build a solar tough system on a model scale. Any
> ideas appreciated.
>
> Will
An outfit named International Solar Collectors has been making parabolic
trough sytle collectors from some type of flexible reflective sheeting. An
articvle was run in Home Power magazine a while back about their solar ice
generator. You could do a search and find them or link to them from Home
Power's site (look under "Other links of Interest" at
http://www.homepower.com).
DCK
Will Wood
Gene Alan Townsend
Will:
Cut some parabolic shaped ribs from 1/2 inch plywood, and get a small 10
ft. roll of 20 in wide aluminum flashing. Using female ribs is best if
your not tracking. These can be attached to a flat board on the back
side using wood screws and glue. Attach the aluminum flashing to the
front of the ribs using small sheet metal screws. It's best if you
polish the aluminum first, before attaching to the ribs. I would
suggest ribs on 1 foot centers, to make it more rigid, for later
polishings.
Cheers,
Gene A. Townsend
Nick Pine
>Will Wood wrote:
>> Does anyone have any ideas on how to make a parabolic mirror about 1.5 by
>> 5 feet? I would like to use the cheapest materials yet have it still be
>> effective. I'm hoping to build a solar tough system on a model scale.
How about slicing some 1/2" foil-faced foamboard across the back the long way
to approximate a parabola, and covering it with a layer of clear plastic to
keep the foil shiny, or attaching some 15 cent/ft^2 aluminized Mylar film to
a thin sheet of exterior flakeboard, then bending it?
Nick
Seamus
wood...@pop.service.ohio-state.edu (Will Wood) said that:
>Hi all,
>
> Does anyone have any ideas on how to make a parabolic mirror about 1.5 by
>5 feet? I would like to use the cheapest materials yet have it still be
>effective. I'm hoping to build a solar tough system on a model scale. Any
>ideas appreciated.
Hi,
You will find what you want at -
http://www.igc.apc.org/raenergy/offaxis.html
Is this groundhog day?
Jim.
Jim Barr
In article <wood.281....@pop.service.ohio-state.edu>, Will Wood
<wood...@pop.service.ohio-state.edu> writes
>Hi all,
>
> Does anyone have any ideas on how to make a parabolic mirror about 1.5 by
>5 feet? I would like to use the cheapest materials yet have it still be
>effective. I'm hoping to build a solar tough system on a model scale. Any
>ideas appreciated.
>
>
>
LARGE crescent shaped gutter, with baking foil attatched to the inside
radius makes a VERY simple and VERY cheap parabolic trough
remove s from swandana to email reply
Jim Barr Machine Conversation
http://www.wandana.demon.co.uk/
Best is the enemy of good enough
Leaves rustle, blades turn, water moves
Barrs Law of Recursive futility:---
If you are smart enough to use one of these.....
.....you can probably manage without one!
J Chace
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Will Wood wrote:
>
> Hi all,
>
> Does anyone have any ideas on how to make a parabolic mirror about 1.5 by
> 5 feet? I would like to use the cheapest materials yet have it still be
> effective. I'm hoping to build a solar tough system on a model scale. Any
> ideas appreciated.
>
> Will
Will,
Attached is a little DOS program I wrote to help plot out the proper
curve for line focused parabola.
Once you decide on a shape you like using the program, have the program
print out your x, and y values and plot the the points on a piece of 1/4
inch plywood. Hot glue some stops (1 X 1 X 3 inches with a wedge shape
cut in the end) on around 11 even spaced points (put one at mid/zero).
Bend a batten of thin(3/8 X 3/4) strait grained wood around these stops
to draw the parabola. You will only need around 5 points acually( you
will notice the curve will intersect ALL the points). This will show you
that you can make your frames(of whatever)just hit the curve
tangentically(?) at 5 or 7 points and still keep the proper shape. This
full sized curve drawing will help you study and shape whatever for the
framwork. You can use formica or reclcled sheet metal or even an old
piece of panneling for that matter for the reflective substrate. I have
found that the cheapest reflective material is mylar($.14 ft^2), though
it is not supposed to hold up in outdoor enviroment very long, maybe a
good year and keep good reflectance??? I am about to try some myself. I
ordered it from nelson enterprises:
http://www.tcmnet.com/~snomo/mylarhome.html
aluminum foil will do if its to needs.
If anyone thinks they might could use this program to assist in building
troughs, feel free. Build many trouhgs and offset many gallons of crudy
oil. Nice free heat energy in a pipe to pump where have you.
Of course be aware you might get steam if its a large one. Steam expands
a LOT so it will burst enclosed systems, make explosions etc., so design
accordingly.
Have fun
J Chace
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Paul and Cindy Kruse
wood...@pop.service.ohio-state.edu (Will Wood) wrote:
>Hi all,
>
> Does anyone have any ideas on how to make a parabolic mirror about 1.5 by
>5 feet? I would like to use the cheapest materials yet have it still be
>effective. I'm hoping to build a solar tough system on a model scale. Any
>ideas appreciated.
Such a thing should be very easy to make. A sheet of plywood will bend
naturally into a parabola, if you secure one edge and apply a force to bend it
at the opposite edge. I would use quarter inch plywood. Marine grade would be
best, since it will have no internal voids that could cause the plywood to kink;
but I have been able to find exterior plywood with no voids by picking through
the pile at Home Depot.
Then all you would have to do is to bond a sheet or aluminum foil onto the wood
surface before you bend it.
While I have never made a mirror like this, I have made several boat hulls with
a parabolic cross section. You would just have to experiment to find the focus
point.
Have a great day,
plk...@iu.net (Paul Kruse)
Matt
Great program, I'll use it in anger one day.
--
Matt Rhys-Roberts T.Eng (Electronics)
* adopt, adapt, improve *
'Give me a land of boughs in leaf, a land of trees that stand;
Where trees are fallen, there is grief; I love no leafless land.' A E Houseman
J
I dont know if I've just been insulted or complimented.
J Chace
J
> Clip program.
>
> I have been thinking about what shape and how to go about making a
> mirror to focus on a section of copper pipe as a potential hot water
> source. I was unable to decode the program and was wondering if there
> was anyother way to get it.
Decode???
Did it show up to some of you as a lot of crazy greeek symbols that I
have seen around??
Seems I may have made a boo-boo in posting the program. My reader showed
it as a link to click on stored on some server somewhere it seems but
not sure how it works. Been on net only around a year or so and not sure
how other readers work, so sorry if I bogged down anyones reader or
something.
Anyone wanting the program, email me and I'll send to to you.
I have recently read it's not cool to attach to a NG, so, sorry 'bout
that. Wont happen again.
J Chace
bob
J Chace <amy...@worldnet.att.net> wrote:
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>Will Wood wrote:
>>
>> Hi all,
>>
>> Does anyone have any ideas on how to make a parabolic mirror about 1.5 by
>> 5 feet? I would like to use the cheapest materials yet have it still be
>> effective. I'm hoping to build a solar tough system on a model scale. Any
>> ideas appreciated.
>>
>> Will
>Have fun
>J Chace
Clip program.
I have been thinking about what shape and how to go about making a
mirror to focus on a section of copper pipe as a potential hot water
source. I was unable to decode the program and was wondering if there
was anyother way to get it.
Last year I made a solar box oven from scrap around the house. It
worked ok and I did boil a quart of water. I didn't want to invest
the time and money in going further yet. I will be retiring this year
in January and will follow up then.
This summer I wanted to try and understand solar water heating better
and had the idea of a long mirror that was focused on a section of
copper pipe. Kind of like a demand hot water heater. I wanted to
measure temperature gains.
thanks bob
bob
J. I got the program and it works fine.
bob