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The only woodworking in this project is in the parabolic solar trough that sucks up the heat, but for those wreckers who've been following my efforts to use the best of hi-tech to produce ultra lo-tech solar devices, this might be interesting...
A group in Mendoza, Argentina saw my fluidyne web pages and has decided to give the solar pump a try. Mendoza Province is arid, but there's underground run-off from the Andes at a depth of 5 m. You can get a quick satellite view of the area at
http://maps.google.com/maps?ll=-32.916485,-68.867798&spn=1.789146,2.27417&z 
and see the no-fuel, no-electricity pump design at
http://www.iedu.com/DeSoto/Projects/Stirling/5mPump.html
Wish us luck!
--
Morris Dovey
DeSoto Solar
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"Morris Dovey" wrote:

You are covered.
Lew
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Lew Hodgett wrote:

Thanks! Encouragement can be a powerful force, and I'll pass it along. I've been tickled with where and by whom the work is being done. Team Pakistan was a small group of engineering students who sometimes worked to the sound of nearby gunfire, Team Sudan is headed by a Brit physicist who, with his MD wife, decided that they could make [and, in fact, are making] the world a better place by taking what they knew and sharing it with the folks of the Sudan. I got an e-mail Friday from Park Falls, Kentucky - an eleventh grader who has her first fluidyne running and now wants to pursue optimization - who (if parents and teachers approve) will be the start of Team USA.
I'm tickled because, although some serious players (NASA, CERN, Harvard, Sandia, Oak Ridge, Oxford, Cambridge,...) have been watching the web site, they've not been contributors. The progress has /all/ come from places and people who couldn't possibly have been predicted...
...and I'm loving every bit of it. :)
--
Morris Dovey
DeSoto Solar
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And so am I, Morris!
I am also impressed by the way the Heifer organisation (heifer.org)provides aid to developing countries. Have you contacted them by any chance? -- Best regards Han email address is invalid
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Han wrote:

I haven't. I suspect that future NGO involvement might be appropriate, but none of what's happening now with this stuff involves any kind of management or accounting structure, and the only accountability any of the participants has is that of being true to the laws of physics and to their own conscience.
All aid-providing organizations /must/ ensure that assets are used responsibly, which imposes exactly those things which would be most counter-productive at this stage. These folks do /not/ need administrivial distraction.
What's needed right now is creative problem-solving of the /very/ highest order, and I don't think that can be bought for money. Fortunately, while it can't be bought, it's already being given.
Later, when (as soon as) there's a version 1.01 of a proven well pump with a known cost, /then/ may be the right time for NGO involvement.
So what /would/ help? I think the folks who're doing the work would benefit most from exactly what I've gotten here - a healthy dosage of affirmation and approval from those who happen to notice what they're doing.
That probably sounds pretty lame. It isn't.
--
Morris Dovey
DeSoto Solar
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wrote:

Wishing you a lot more than luck, Morris.
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Dave Balderstone wrote:

Thanks! The high level Google satellite view doesn't show conditions very well (much too green) - you can get a better idea of what they're dealing with by zooming down anywhere.
When the folks in Mendoza told me it was a big wine-producing area, I took one look and quipped back that it looked about perfect for growing raisins. :)
More than luck? Well, _water_ would be good. Methinks they need a few apple and peach orchards; and if they have wine and apples, then they'll need alfalfa to support cheese production...
...and, of course, they'll need to grow trees for the woodworkers. ;->
Plus - if we can get this thing working, there's a team already forming in Khartoum who'll be able to put it to work immediately to expand the arable area on either side of the Nile.
--
Morris Dovey
DeSoto Solar
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wrote:

That's freakin' awesome.
How can we contribute to the effort?
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Dave Balderstone wrote:

Wow, you caught me flat-footed on that one - but I can think of a number of needs:
[1] There isn't yet a non-electrical tracking system to keep a trough steadily aimed at the sun. A polar mount like that used for satellite dishes (rotate trough on long axis to track the sun during the day, and elevation +/-23.5° seasonal adjustment) might be ideal. I've been trying to figure out a hydraulic solution, but I'm sure there's more than one way to skin this cat. Whatever the solution is, it'll need to keep the trough steady in even gusty conditions.
[2] The next developmental stage will be wells deeper than the 27 feet or so that water can be sucked without pulling a vacuum. I identified the problem, stuck a post-it on the wall, and moved on. If there's a pump guru somewhere who can figure out how to use the fluidyne's alternating pressures to do that job, there's a real opportunity to be a hero by showing how to do it. My best guess was to use two pumps - one at the bottom of the well to pump the water, and another at the surface to pump hot air down to drive the water pump. I think there might be a better way, but I don't know what it might be.
[3] There's a need for a /really/ inexpensive, long-lasting check valve. A DIY solution might be ideal but isn't required. It needs to open easily (as in not using up pumping power to overcome spring force or weight of the moving part) and seal completely on closure. The PVC check valves that I was able to buy locally are expensive ($22/ea) and don't seal well at all.
[4] /Major/ good karma would accrue to anyone who could provide development teams with pressure, temperature, and fluid piston displacement information for both hot and cold heads at a one kHz or so sampling rate for display on a PC or laptop with via, say, a USB2 interface. One of the biggest headaches is that we can't see what's going on inside the engine. There's a commercial opportunity here, too - because once the developers are done, a tool like this would be needed for maintainers to trouble-shoot failing pumps.
[5] Fluidynes operate on the temperature differential between the hot and cold heads, and we'll probably always be looking for ways to more effectively get heat into the hot head and out of the cold head without significantly affecting the cost or requiring custom parts.
[6] There'll also be a "forever" search for better/less expensive materials throughout. I've thought about casting ceramic/concrete pump bodies and daydreamed about molded one-piece high-temperature plastic pump bodies, but don't know enough materials to even be dangerous. I found out the hard way that PVC doesn't much like to be heated above the boiling temperature of water (it wasn't very pretty when I tried that).
And the last item for tonight (I'm about to fall asleep at my keyboard) is:
[7] A battery/solar powered electronic device (preferably hand-held) that tells if and how far down there's enough water to justify a well and pump. It'd also be a big help to know if there are any solid obstacles (like boulders) between the device and the water.
Probably I should put this list on a project web page. Tomorrow.
--
Morris Dovey
DeSoto Solar
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....other than a human with a wrench and a few instructions!
JP ************** Kiss. : o
PS - I made some clamping cauls!!!! They're excellent!
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Jay Pique wrote:

I like simple, too. Ok, you get the first 10-year stint, and after five years of non-slacking tracking, you'll receive a new pair of welding goggles. :-T
I think the economics (everywhere) are in favor of a more energy efficient solution - and I think we'd all prefer to see that kid in school.

Good news, indeed.
--
Morris Dovey
DeSoto Solar
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<snip>

<snip/> -- When you said earlier that the next step was a "10m solution" , I thought about two pumps as well, but with a tank buried half way, stepping the water up. Might need to consider overflow or dry tank conditions; but, if the pump is self-priming, a dry tank shouldn't cause a problem for the top pump. Just a thought.
Ed
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StL.Ed wrote:

I just copied your post into my "Things to Consider" directory, and will encourage you to keep that challenge on your back burner. We still have a lot to learn about is and isn't reasonable, and I suspect that what we learn with shallow wells may very well influence our thinking for deeper wells.
Thanks!
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Morris Dovey
DeSoto Solar
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A clockwork mechanism pops into my head.
Mutter, mutter. Moving that reflector and keeping it steady in winds would need a fairly robust mechanism. Probably weight driven -- simpler than springs and probably cheaper, given that you need quite a bit of energy to drive the mechanism.
Some kind of funky cam to track the sun and return during the night. You need an escapement. It doesn't have to be real accurate. A pendulum is easy, but a balance wheel might be more reliable. Naw. Use a pendulum and enclose it in a box with the weights and mechanism. A couple of dozen parts. Most could be stamped out of aluminum or hand made with a file and a few jigs. Mutter, mutter.
These solar cookers were all over Tibet, even places that had other sources of power:
http://douglasjohnson.org/pictures/Solar%20Cooker.jpg
-- Doug
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----snip-----
You probably are already doing this, but one obvious way to cool the cold side is with the water being pumped out of the ground, which is normally significantly colder than ambient air temps, at least during summer.
WayneJ
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WayneJ wrote:

The "clean" way to do that appears be to be adding a water jacket to the cold head, and route the well water through that jacket.
The problem is that when the well pipe drains (or starts dry), that jacket will stay dry until the pump has cycled enough times to bring water up to fill it. Then the air-filled jacket will allow heat to build up in the cold head, and oscillation will halt because of an the resulting insufficient heat differential.
The "dirty" method is to simply splash the discharge water over the cold head, which will solve the cooling problem but opens the door to a host of other problems - including contamination of the well.
At present both hot and cold heads are 24" sections of the tubing used for semi truck exhaust stacks, with a flue cap (thimble?) brazed to one end. That's the Iowa version. The Pakistani version used different materials, and others' will be adapted to suit what's available locally, which makes standardization an interesting issue. :)
--
Morris Dovey
DeSoto Solar
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It should be possible to arrange the pipe connections to the jacket such that the jacket does not empty when the well pipe drains. If the ASCII drawing stays intact, this would be an example. The drawing is a section through the jacket and the cold head. I realize the drawing of the cold head is probably incorrect, but the concept should be adaptable.
___| |___ _______| | | |_______ IN \ | | OUT _______ \ | | _______ | | | | | | | | | | | | | | | | | | | | | | | | |___| |___| | |
The water in and out pipes are at the same level. A deflector at the opening of the in pipe causes circulation in the jacket while water flows. When the pump stops and the well pipe drains back air enters at the out pipe, but only the water above the bottom of the in pipe will drain out of the jacket. At start up, the substantial amount of water in the jacket will sink enough heat to allow the pump to start the water flowing. The size of the jacket may need to be adjusted to ensure reliable start up but it shouldn't need to be very large. The jacket would have to be primed for a dry start and drained if freezing conditions occur.

Agreed, this is probably not a good idea.

Is standardization needed or desirable? Use of local resources would seem to be a good thing.
Is there a better place to continue this discussion? Perhaps it is getting a bit OT for rec.woodworking.
WayneJ
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WayneJ wrote:

You can safely bet that this (or something very like) /will/ be tested because the possible performance improvement is so attractive. :)

It's an interesting aspect to consider, and there's a powerful urge on the part of "geeky" types (like me) to maximize efficiency, and it's not always so easy to remember that the primary objective is to move water, not build a technical marvel. :-/
When I got really tough with myself, I decided that it might be wiser just to get a minimal pump working and leave refinement for later. I'm absolutely certain that, once it's working, more people will become involved and there will be no shortage of improvements. With luck, at least a few of those improvements will provide breakthrough (technical quantum leap) enhancement.

You're right, there is - this is completely topical in news:alt.solar.thermal - and my e-mail address is publicly available (and all mail with "Solar" in the subject goes to the front of the queue).
--
Morris Dovey
DeSoto Solar
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You are welcome to keep it going here guys. It's a hell lot better and more interesting than all the political scientology (tmTW).
Luigi
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wrote:

You are welcome to keep it going here guys. It's a hell lot better and more interesting than all the political scientology (tmTW).
Luigi
I'll second that : )
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