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| Science Forum Index » Engineering - Joining (Welding) Forum » Saw the damnest thing today... |
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| SteveB... |
 Posted: Thu Oct 15, 2009 6:41 pm |
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Guest
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A parabolic reflector mirror, made of the stuff that is inside those tubular
skylights, about 9 square feet, with a turning metal base, focused out to a
platform where a big pot of pot roast was cooking. $589. Didn't get the
brand name. Sure was working good, though. But one would have to sit there
and tend it and move the thing as the day wore on. Looked like it worked
good, though. Wouldn't be hard to build, either.
Steve |
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| Stuart Wheaton... |
| Posted: Thu Oct 15, 2009 7:40 pm |
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Guest
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SteveB wrote:
[quote:b81303c9ad]A parabolic reflector mirror, made of the stuff that is inside those tubular
skylights, about 9 square feet, with a turning metal base, focused out to a
platform where a big pot of pot roast was cooking. $589. Didn't get the
brand name. Sure was working good, though. But one would have to sit there
and tend it and move the thing as the day wore on. Looked like it worked
good, though. Wouldn't be hard to build, either.
Steve
[/quote:b81303c9ad]
If you know the date and time, and your location, it ought to be pretty
simple to put a servo drive on it to keep it focused too. |
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| RoyJ... |
| Posted: Thu Oct 15, 2009 8:31 pm |
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Guest
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I have a bunch of students dealing with the same thing. Once you figure
out you need to toss the X-Y-Z mount and set up an equatorial mount,
things go a LOT easier. The equitorial mount sets up a plane that mimics
the path of the sun for any given day, you just need to rotate the
collector on that plane to keep it in focus.
Stuart Wheaton wrote:
[quote:792f5ecb04]SteveB wrote:
A parabolic reflector mirror, made of the stuff that is inside those
tubular skylights, about 9 square feet, with a turning metal base,
focused out to a platform where a big pot of pot roast was cooking.
$589. Didn't get the brand name. Sure was working good, though. But
one would have to sit there and tend it and move the thing as the day
wore on. Looked like it worked good, though. Wouldn't be hard to
build, either.
Steve
If you know the date and time, and your location, it ought to be pretty
simple to put a servo drive on it to keep it focused too.[/quote:792f5ecb04] |
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| SteveB... |
| Posted: Fri Oct 16, 2009 1:01 am |
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Guest
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"RoyJ" <spamless at (no spam) microsoft.net> wrote in message
news:T9SdnbRcM-6NRkrXnZ2dnUVZ_sednZ2d at (no spam) earthlink.com...
[quote:38fc29c73f]I have a bunch of students dealing with the same thing. Once you figure out
you need to toss the X-Y-Z mount and set up an equatorial mount, things go
a LOT easier. The equitorial mount sets up a plane that mimics the path of
the sun for any given day, you just need to rotate the collector on that
plane to keep it in focus.
Stuart Wheaton wrote:
SteveB wrote:
A parabolic reflector mirror, made of the stuff that is inside those
tubular skylights, about 9 square feet, with a turning metal base,
focused out to a platform where a big pot of pot roast was cooking.
$589. Didn't get the brand name. Sure was working good, though. But
one would have to sit there and tend it and move the thing as the day
wore on. Looked like it worked good, though. Wouldn't be hard to
build, either.
Steve
If you know the date and time, and your location, it ought to be pretty
simple to put a servo drive on it to keep it focused too.
[/quote:38fc29c73f]
This one swung horizontally, and there was an adjustment knob for the height
of the hot spot on the pot.
Steve |
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| Bob La Londe... |
| Posted: Fri Oct 16, 2009 9:12 am |
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"SteveB" <oldfart at (no spam) depends.com> wrote in message
news:3cilq6-tpc2.ln1 at (no spam) news.infowest.com...
[quote:2ce0bb3770]
"RoyJ" <spamless at (no spam) microsoft.net> wrote in message
news:T9SdnbRcM-6NRkrXnZ2dnUVZ_sednZ2d at (no spam) earthlink.com...
I have a bunch of students dealing with the same thing. Once you figure
out you need to toss the X-Y-Z mount and set up an equatorial mount,
things go a LOT easier. The equitorial mount sets up a plane that mimics
the path of the sun for any given day, you just need to rotate the
collector on that plane to keep it in focus.
Stuart Wheaton wrote:
SteveB wrote:
A parabolic reflector mirror, made of the stuff that is inside those
tubular skylights, about 9 square feet, with a turning metal base,
focused out to a platform where a big pot of pot roast was cooking.
$589. Didn't get the brand name. Sure was working good, though. But
one would have to sit there and tend it and move the thing as the day
wore on. Looked like it worked good, though. Wouldn't be hard to
build, either.
Steve
If you know the date and time, and your location, it ought to be pretty
simple to put a servo drive on it to keep it focused too.
This one swung horizontally, and there was an adjustment knob for the
height of the hot spot on the pot.
Steve
[/quote:2ce0bb3770]
I would think the easiest thing to do would be to use optical pickups to
activate servo motors. Seems pretty simple to me. Put optical relays at
the bottom of tubes mounted just off parallel to the axis of the parabola.
Set it on a 365 day timer that rough positions the dish at sunset for each
day of the year, and then shuts down the controller tubes until sunrise
time. From one day to the next the track of the sun isn't going to be much
different than the day before, so you could just swing it back to rest at
sunset on one axis and let your alignment relays do the fine adjust when the
sun comes up the next day. Maybe add some kind of light level meter to deal
with cloudy days if this is intended to be a totally unattended
installation. |
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| Larry Fishel... |
| Posted: Fri Oct 16, 2009 7:03 pm |
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On Oct 16, 11:12 am, "Bob La Londe" <nos... at (no spam) nospam.no> wrote:
[quote:53b5bf29e4]I would think the easiest thing to do would be to use optical pickups to
activate servo motors. Seems pretty simple to me. Put optical relays at
the bottom of tubes mounted just off parallel to the axis of the parabola..
[/quote:53b5bf29e4]
Unless I misunderstand, this will only work if the reflector rotates
around the focus (which is likely impractical). Otherwise, you have to
find a way to split the angle between the sun and the pot, not keep
the reflector pointed at the sun... |
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| Jim Wilkins... |
| Posted: Sat Oct 17, 2009 4:22 am |
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On Oct 17, 1:03 am, Larry Fishel <ldfis... at (no spam) yahoo.com> wrote:
[quote:6ecda27020]On Oct 16, 11:12 am, "Bob La Londe" <nos... at (no spam) nospam.no> wrote:
I would think the easiest thing to do would be to use optical pickups to
activate servo motors. Seems pretty simple to me. Put optical relays at
the bottom of tubes mounted just off parallel to the axis of the parabola.
Unless I misunderstand, this will only work if the reflector rotates
around the focus (which is likely impractical). Otherwise, you have to
find a way to split the angle between the sun and the pot, not keep
the reflector pointed at the sun...
[/quote:6ecda27020]
If the reflector assembly rotates around its center of gravity it
should point half way between the sun and the pot roast, which isn't a
point target and doesn't require precise focus.
I think I would passively drive the reflector with a surplus gearmotor
or a cheap small motor with string pot feedback for time-of-day
position and fine tune it by balancing the radiation intensity between
sensors on either side of the target, facing the reflector. The
sensors might be copper tubing heat pipes with a diode bridge clamped
on, a significant temperature difference would unbalance the bridge,
giving a magnitude and direction output.
http://www.micro-examples.com/public/microex-navig/doc/098-temperature-sensor.html
jsw |
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| amdx... |
| Posted: Sat Oct 17, 2009 7:11 pm |
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"Bob La Londe" <nospam at (no spam) nospam.no> wrote in message
news:hba2gc$2me$1 at (no spam) news.eternal-september.org...
[quote:16c8caf09e]"SteveB" <oldfart at (no spam) depends.com> wrote in message
news:3cilq6-tpc2.ln1 at (no spam) news.infowest.com...
"RoyJ" <spamless at (no spam) microsoft.net> wrote in message
news:T9SdnbRcM-6NRkrXnZ2dnUVZ_sednZ2d at (no spam) earthlink.com...
I have a bunch of students dealing with the same thing. Once you figure
out you need to toss the X-Y-Z mount and set up an equatorial mount,
things go a LOT easier. The equitorial mount sets up a plane that mimics
the path of the sun for any given day, you just need to rotate the
collector on that plane to keep it in focus.
Stuart Wheaton wrote:
SteveB wrote:
A parabolic reflector mirror, made of the stuff that is inside those
tubular skylights, about 9 square feet, with a turning metal base,
focused out to a platform where a big pot of pot roast was cooking.
$589. Didn't get the brand name. Sure was working good, though. But
one would have to sit there and tend it and move the thing as the day
wore on. Looked like it worked good, though. Wouldn't be hard to
build, either.
Steve
If you know the date and time, and your location, it ought to be pretty
simple to put a servo drive on it to keep it focused too.
This one swung horizontally, and there was an adjustment knob for the
height of the hot spot on the pot.
Steve
I would think the easiest thing to do would be to use optical pickups to
activate servo motors. Seems pretty simple to me. Put optical relays at
the bottom of tubes mounted just off parallel to the axis of the parabola.
Set it on a 365 day timer that rough positions the dish at sunset for each
day of the year, and then shuts down the controller tubes until sunrise
time. From one day to the next the track of the sun isn't going to be
much different than the day before, so you could just swing it back to
rest at sunset on one axis and let your alignment relays do the fine
adjust when the sun comes up the next day. Maybe add some kind of light
level meter to deal with cloudy days if this is intended to be a totally
unattended installation.
Do a search on some of the solar energy groups, forums they have several[/quote:16c8caf09e]
system
designed to do this.
Mike |
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| TinLizziedl... |
| Posted: Sun Oct 18, 2009 2:15 am |
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Guest
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In article <q3skq6-3lm2.ln1 at (no spam) news.infowest.com>, oldfart at (no spam) depends.com
says...
[quote:feac5f7449]A parabolic reflector mirror, made of the stuff that is inside those tubular
skylights, about 9 square feet, with a turning metal base, focused out to a
platform where a big pot of pot roast was cooking. $589. Didn't get the
brand name. Sure was working good, though. But one would have to sit there
and tend it and move the thing as the day wore on. Looked like it worked
good, though. Wouldn't be hard to build, either.
Steve
[/quote:feac5f7449]
Use an equatorial mount like many telescopes do to automate the
tracking.
That would make a great hot-water heater for camping or temporary home
use, too.
Aim your sunbeam at a cobbled together tank-radiator showerhead/sink....
--
Tin Lizzie
"Elephant: A mouse built to government specifications."-Lazarus Long |
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| SteveB... |
| Posted: Sun Oct 18, 2009 9:08 pm |
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Guest
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"TinLizziedl" <nothere at (no spam) donttry.com> wrote in message
news:MPG.25446e71668979398973c at (no spam) news.west.earthlink.net...
[quote:684b1cf28f]In article <q3skq6-3lm2.ln1 at (no spam) news.infowest.com>, oldfart at (no spam) depends.com
says...
A parabolic reflector mirror, made of the stuff that is inside those
tubular
skylights, about 9 square feet, with a turning metal base, focused out to
a
platform where a big pot of pot roast was cooking. $589. Didn't get the
brand name. Sure was working good, though. But one would have to sit
there
and tend it and move the thing as the day wore on. Looked like it worked
good, though. Wouldn't be hard to build, either.
Steve
Use an equatorial mount like many telescopes do to automate the
tracking.
That would make a great hot-water heater for camping or temporary home
use, too.
Aim your sunbeam at a cobbled together tank-radiator showerhead/sink....
--
Tin Lizzie
"Elephant: A mouse built to government specifications."-Lazarus Long
[/quote:684b1cf28f]
I have used the simple bag Solar Showers, and come back to camp after a day
out, and had to add cool water because the water was just too hot to shower
in. A poor boy system like you suggest would be a good camping thing, and
easy to do. I had considered it in my camping days, then got into
motorhoming and forgot all about it. ;-)
Steve |
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| Bob La Londe... |
| Posted: Mon Oct 26, 2009 7:15 pm |
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Guest
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"Larry Fishel" <ldfishel at (no spam) yahoo.com> wrote in message
news:a4bedc87-18b1-4390-869c-b0363863735a at (no spam) k17g2000yqb.googlegroups.com...
[quote]On Oct 16, 11:12 am, "Bob La Londe" <nos... at (no spam) nospam.no> wrote:
I would think the easiest thing to do would be to use optical pickups to
activate servo motors. Seems pretty simple to me. Put optical relays at
the bottom of tubes mounted just off parallel to the axis of the
parabola.
Unless I misunderstand, this will only work if the reflector rotates
around the focus (which is likely impractical). Otherwise, you have to
find a way to split the angle between the sun and the pot, not keep
the reflector pointed at the sun...
[/quote]
Nope. Just like an old style satellite dish swings to point along the line
of geo syncs along the equator it would swing so that the axis of symetry is
always pointed at the sun. You just suspend your pot roast in front of the
dish from struts at the focal point. Or your kettle of liquid salts as the
case may be. |
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