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
and see the no-fuel, no-electricity pump design at
Wish us luck!
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. :)
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? --
email address is invalid
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
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.
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
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.
Wow, you caught me flat-footed on that one - but I can think of a number
 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.
 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.
 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.
 /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.
 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.
 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:
 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.
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
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.
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.
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
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
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
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.
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. :)
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.
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).
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