Solar powered stirling engine project

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Sun, Aug 27, 2006, 9:05pm (EDT-3) snipped-for-privacy@spamcop.net did writeth: Not that you said they actually did hurt anybody but to be clear, AFAIK, no one has ever been hurt by cutting into a deliberately spiked tree. <snip> As for revenue used to fund game conservation, I think you'll find that most 'tree huggers' are opposed to game conservation considering it to be tampering with nature by creating an imbalance in the animal populaitons.
Perhaps no person has been hurt, but that's certainly not from lack of fntent.
The tree huggers got their way a number of years ago, somewhere on the east coast. I have forgotten the exact reference, will look it up if I can - I idid seephotos. Seems they got an area closed off to all hunting. Within five years the deer population was suffering from malnutrition, stunted growth, and disease. Looked like the deer population would be totally decimated within a few more years. But someone with sense allowed hunting again, and the deer population regained health, normal groth, and no disease. It did take a number of years for this to happen tho. The tree huggers forget, man has encroached on these animals habitat, pretty well done away with natural preditors, etc. No hunting and they quickly consume their usual forage when the herd increases. If they'e not culled by hunting they move out of their range to find new food sources, too often farmers' fields. In the mortal world the tree huggers' and daisy eaters's dreams don't come true.
Myself, I'm conservative. Don't hunt anymore myself, but am a firm believer in hunting as a viable game management and conservtion resource. If it wasn't for legal hunting and hunters there wouldn't be near the amount of game there is, or the amount of species there is. It's got to be controlled tho, limits, perhaps closed seasons at times, use some sense in other words.
JOAT Justice was invented by the innocent. Mercy and lawyers were invented by the guilty.
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J T wrote:

The Eastern deer population has exploded for two reasons. First, there is the proliferation of 'edge environment' wherein the deer thrive and secondly due to overhinting of natural predators, as in, there aren't any anymore.
However, if left alone the population would ebb and wane naturally.

I've got nothing against hunting and fishineg either. But I do have a bone to pick with some of the insane arguments. More species fue to hunting, no, I don't think so. If you can name a species that has been saved from extinction by hunting, go ahead.
--

FF


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Morris, two questions:
1) Could you post the responses you've gotten on the engine pump from other newsgroups on your website?
2) If this is solar powered, and you need to track the sun, one would assume the heated tube would need to be tilted. Will the engine work with the heated tube tilted?
Thanks...
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Smaug Ichorfang (in Xns982ECCC9DF64Dgoblineater@207.115.17.102) said:
| Morris, two questions:
| 1) Could you post the responses you've gotten on the engine pump | from other newsgroups on your website?
I'm not sure of the propriety of doing so; but you can spot the (mostly short) threads quickly if you either visit the newsgroups or do a Google Groups search on my recent posts with my name as author and (solar OR stirling) in the subject.
The other groups to which I've posted to have been:
news:alt.binaries.pictures.woodworking news:alt.engineering news:alt.sci news:alt.solar.thermal news:sci.engr.mech
The most interesting and potentially useful info I've received has been direct e-mail - and tellingly, most not from people on the scientific and engineering groups - but from fredfighter and Robatoy here on the wreck.
[ methinks more scientists and engineers would do well to take up woodworking :-) ].
| 2) If this is solar powered, and you need to track the sun, one | would assume the heated tube would need to be tilted. Will the | engine work with the heated tube tilted?
The planned heat source is a trough-type parabolic reflector with a pipe running down the focus. I'm planning 2-axis tracking using a pair of expansion chambers and a double-acting hydraulic cylinder for each axis. If I get it right, this should track the sun from horizon-to-horizon all year long.
One of the experiments with the desktop version was to test exactly that. It'll run aslant; but not tipped over flat. I didn't even try to measure angles since all I wanted was verification that a larger one wouldn't require critical adjustment for plumb during installation. "Mostly straight-up" is close enough.
There is a built-in delay factor with my web pages. This is an "after-hours" project for me, and it gets time, energy, and materials only after the stuff that I hafta-do has been done - and the web page has less priority than almost everything else because I'd rather _do_ than _talk_ about getting this thing working...
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto
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Morris Dovey wrote:

You could also post links to the google page for the thread(s)

You could come close to doing that with a one-axis drive.
DAGS "Equatorial Telescope Mount" to see how.

--

FF


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snipped-for-privacy@spamcop.net (in snipped-for-privacy@i42g2000cwa.googlegroups.com) said:
| Morris Dovey wrote: || Smaug Ichorfang (in Xns982ECCC9DF64Dgoblineater@207.115.17.102) || said: || ||| Morris, two questions: || ||| 1) Could you post the responses you've gotten on the engine pump ||| from other newsgroups on your website? || || I'm not sure of the propriety of doing so; but you can spot the || (mostly short) threads quickly if you either visit the newsgroups || or do a Google Groups search on my recent posts with my name as || author and (solar OR stirling) in the subject. || | | You could also post links to the google page for the thread(s)
Ok - Google will provide. Mind the wrap(s):
http://groups.google.com/group/alt.solar.thermal/browse_thread/thread / fc6b942caa3429a/d2e529133ec1c1ac?lnk=st&q=insubject%3Astirling+author% 3Amrdovey%40iedu.com&rnum=2&hl=en#d2e529133ec1c1ac
http://groups.google.com/group/sci.engr.mech/browse_thread/thread/9c3e d1fda71fb26/bb81711aa6c3b7b1?lnk=st&q=insubject%3Astirling+author%3Amr dovey%40iedu.com&rnum=4&hl=en#bb81711aa6c3b7b1
http://groups.google.com/group/alt.engineering/browse_thread/thread/26 bc8707b192d621/96740daeb1a323bf?lnk=st&q=insubject%3Astirling+author%3 Amrdovey%40iedu.com&rnum&hl=en#96740daeb1a323bf
http://groups.google.com/group/alt.sci/browse_thread/thread/37cc76e72e 8f4288/12e576613f7bb13c?lnk=st&q=insubject%3Astirling+author%3Amrdovey %40iedu.com&rnum$&hl=en#12e576613f7bb13c
(news:alt.binaries.ptictures.woodworking - not archived on google)
|| The planned heat source is a trough-type parabolic reflector with a || pipe running down the focus. I'm planning 2-axis tracking using a || pair of expansion chambers and a double-acting hydraulic cylinder || for each axis. If I get it right, this should track the sun from || horizon-to-horizon all year long. | | You could come close to doing that with a one-axis drive. | | DAGS "Equatorial Telescope Mount" to see how.
I found http://science.howstuffworks.com/telescope5.htm which explains az-el and equatorial mounts. Both require two-axis adjustment. The collector will need to adjust at least +/- 23.5 degrees on one axis and at least 180 degrees on the other. I say "at least" because I can't depend on any specialized skills on the part of the installer. Remember - this thing is required to operate sunup to sundown every day of the year without human assistance.
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto
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Morris Dovey wrote:

Yes, with a equatorial mount it will need to move from +23.5 to -23.5 and back once per year. I think that could be done by having the user adjust it once a week or so, assuming your collector can tollerate a error of 2 or 3 degrees in declination.
If the collector takes the form of a U_shaped mirror shining on a pipe parrallel to the polar axis it should be VERY insensitive to declination errors.
Consider the horseshoe mount (split ring mount) in particular as it is very compact and can be designed without or with minimal counterweighting. The key to low-power tracking is balance so that you are not working against gravity. Telescopes weighing tens of tons can easily be moved by hand.

Why does it need to operate for a whole year without human assistance?
Wouldn't all day after being reset in the morning suffice?
--

FF


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snipped-for-privacy@spamcop.net (in snipped-for-privacy@b28g2000cwb.googlegroups.com) said:
| Morris Dovey wrote: || || || I found http://science.howstuffworks.com/telescope5.htm which || explains az-el and equatorial mounts. Both require two-axis || adjustment. The collector will need to adjust at least +/- 23.5 || degrees on one axis | | Yes, with a equatorial mount it will need to move from +23.5 to | -23.5 and back once per year. I think that could be done by having | the user adjust it once a week or so, assuming your collector can | tollerate a error of 2 or 3 degrees in declination. | | If the collector takes the form of a U_shaped mirror shining on a | pipe parrallel to the polar axis it should be VERY insensitive to | declination errors.
Agreed - but if adjustment is needed, then why not make it self-adjusting if that can be done at small cost and with high reliability?
| Consider the horseshoe mount (split ring mount) in particular as | it is very compact and can be designed without or with minimal | counterweighting. The key to low-power tracking is balance so | that you are not working against gravity. Telescopes weighing | tens of tons can easily be moved by hand.
We're in agreement still. Gravity is not our friend here - and neither is wind. What's needed is a well-balanced system that resists wind forces and incorporates a closed-loop control system with adequate negative feedback. [ Shazam! Did I really say that? ;-) ]
|| and at least 180 degrees on the other. I say "at least" because I || can't depend on any specialized skills on the part of the || installer. Remember - this thing is required to operate sunup to || sundown every day of the year without human assistance. | | Why does it need to operate for a whole year without human | assistance? | | Wouldn't all day after being reset in the morning suffice?
Because Murphy is alive and well. Even reliable humans occasionally screw up - and it generally works best to design systems that do <whatever> with better than human reliability. With a focus temperature in excess of Bradbury's Fahrenheit 452, I'd be very happy if people just ignored it and enjoyed the benefits.
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto
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Morris Dovey wrote:

Because it adds cost and reduces the reliability.
Using an equatorially mouted telescope makes the advantages really clear in a way that is hard to appreciate on paper.

Sounds like expensive, complex, unlreliable, overkill.
What is needed is a clock motor assembly that will turn at a rate of one revolution per day. It can be gravity driven, llike a cukoo clock, or spring driven, like an alarm clock. The clock only needs to be precise to a couple of minutes per day so long as the operator resets the collector to the east each morning. If it resets itself, which would be doable but a fair bit more complicated, then the clock would need to be more accurate.

On a daily basis the operator would, at most, have to turn it back to the east (on one axis only). I'm assuming a friction clutch for simplicity. Otherwise he'd have to release the clutch, turn it back, and reengage the clutch.
--

FF


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Mon, Aug 28, 2006, 6:55pm (EDT-3) snipped-for-privacy@spamcop.net now doth put out: The Eastern deer population has exploded for two reasons. First, there is the proliferation of 'edge environment' wherein the deer thrive and secondly due to overhinting of natural predators, as in, there aren't any anymore. However, if left alone the population would ebb and wane naturally. I've got nothing against hunting and fishineg either. But I do have a bone to pick with some of the insane arguments. More species fue to hunting, no, I don't think so. If you can name a species that has been saved from extinction by hunting, go ahead.
Yeah, sure, right. http://query.nytimes.com/gst/fullpage.html?res=950DE2DE1E3FF93AA25752C1A96F948260
When I wrote, I was meaning the taxes generaged by hunting, not hunting in and of itself. I can't name any species saved from extinction, because if they aren't extinct it's not certain they would have become extinct, now is it? Thought it would be undersood, silly me That reminded me of a woman I talked with some years back. We had gotten into beliefs, she was a firm believer in her religion as it turned out. I mentioned I believe in reincarnation; she immediatelly demanded proof it existed. Of course I couldn't offer any proof, merely my faith that it was/is so. She immediately then terminated all communications. Interesting in that at the same time she expected me to believe, without any proof, in her religious beliefs. I think that pretty well does it for me.
JOAT Justice was invented by the innocent. Mercy and lawyers were invented by the guilty.
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Morris Dovey wrote:

If you brouse the engineering texts at your local University Library you can probably find an explanation of the underlying theroy--if you don't find it online.I remember covering it and the professor demoed a sterno powered desktop unit in the classroom. It has been too long for me to remember much about it though.
Also many years ago a friend told me that the had seen a solar- powered Stirling engine powered water pump that had been designed for farm use--similar to the wind powered uints. It may have been a manufactured unit.
I'll bet it was similar to your design. One problem I see with the simple open loop design is that evaporation and condensation will transfer water from the engine to the pump resevoir. It will require periodic repriming.
Maybe that could be done automatically.
Thanks for posting.
--

FF


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snipped-for-privacy@spamcop.net (in snipped-for-privacy@74g2000cwt.googlegroups.com) said:
| Morris Dovey wrote: || || It's be like winning the lottery if someone could explain to me (in || terms I could understand) why and how (with formulas!) the darn || thing works so I could do some actual design. | | If you brouse the engineering texts at your local University Library | you can probably find an explanation of the underlying theroy--if | you don't find it online.I remember covering it and the professor | demoed a sterno powered desktop unit in the classroom. It has been | too long for me to remember much about it though.
I've had two "toy" sterlings - one was heated by a small alcohol burner and the other used a small parabolic dish. Both engines had two pistons separated by 90 degrees tied to a common crankshaft. They were fascinating; but not particularly educational. As far as I was concerned, they may as well have been PFM-powered.
| Also many years ago a friend told me that the had seen a solar- | powered Stirling engine powered water pump that had been | designed for farm use--similar to the wind powered uints. It | may have been a manufactured unit.
I wish I'd seen it!
| I'll bet it was similar to your design. One problem I see with | the simple open loop design is that evaporation and condensation | will transfer water from the engine to the pump resevoir. It will | require periodic repriming. | | Maybe that could be done automatically.
Perhaps. I'll just have to get the darned thing built and see how much fluid loss there actually is. I may be able to get by with just a few drops of oil or some styrofoam beads/fluff in the open column.
| Thanks for posting.
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto
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Morris Dovey wrote:

You can't tell much by looking at the outside of the engine.

Quite possibly a patent desclosure could be located at the US Patent Office. I don't know if you can search century-old patents online.
BTW, I found that places that sell aquarium supplies, like the major Pet store chains, have very small inexpensive check valves.
Also, did you get my email?
--

FF


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snipped-for-privacy@spamcop.net (in snipped-for-privacy@74g2000cwt.googlegroups.com) said:
| Quite possibly a patent desclosure could be located at the US | Patent Office. I don't know if you can search century-old patents | online.
I'm not sure; but think expired patents would be valuable in terms of "prior art".
| BTW, I found that places that sell aquarium supplies, like the major | Pet store chains, have very small inexpensive check valves.
I hadn't (and probably wouldn't have) thought of that.
| Also, did you get my email?
I did (two of them from you and a batch from other people). I've been frying my circuits trying to absorb all the input!
Your second e-mail suggests that what I have may actually be a steam/stirling hybrid, and I'm still working my way through what that means in terms of modeling not-yet-built engines.
Several other people also suggested cold-side cooling, something I hadn't concerned myself with, and I'm taking a look at low cost ways to do that.
I was fairly comfortable watching the little desktop unit run; and now I'm beginning to sympathize with the centipede asked to tell how he walks with all those legs. :-)
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto
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