I've just added the first photos to my solar stirling web page -
showing an electrical (resistance) heater being used for testing and
the early construction of the wooden prototype parabolic trough frame.

As promised, progress is slow and jerky - but the engine appears to
scale nicely (the most recent engine has a stroke of ~5" with 30W
input).

Many thanks to all who've offered encouragement!

More later...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

Morris Dovey (in ) said:

| I've just added the first photos to my solar stirling web page -

A URL would probably help...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/StirlingProject.html

"Morris Dovey" tatlized us with his backyard inventions

Morris Dovey (in ) said:

| I've just added the first photos to my solar stirling web page -

A URL would probably help...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/StirlingProject.html



Good on ya Morris. The world is a better place with you in it.

Morris Dovey said:

Morris Dovey (in ) said:

| I've just added the first photos to my solar stirling web page -

A URL would probably help...

Not having kept up with the past history of this project, am I correct
in assuming that this is to be used as a working fluid pump for a
solar heating arrangement?

And since you seem to have experience along these lines, an additional
question. I have looked at the large solar water heating panels on a
few homes, and have always felt that due to a reduction in exposed
surface area (thermal loss) that a tracking parabolic reflector
focused on a small cylindrical "boiler" would be more efficient than
the large panel designs. Is this, in fact, the case? Or am I
dreaming again - I haven't kept up with changes in this technology in
19 years.

My other quandary is, "How the heck do you find time and enthusiasm to
pursue all of this stuff?"

FWIW

That is a nice sized trough, it should produce good heat.

"Morris Dovey" wrote in message ...
Morris Dovey (in ) said:

| I've just added the first photos to my solar stirling web page -

A URL would probably help...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/StirlingProject.html

Morris Dovey wrote:
| I've just added the first photos to my solar stirling web page -
http://www.iedu.com/DeSoto/StirlingProject.html

Have you looked at other peoples liquid piston stirling pumps?

http://www.linux-host.org/energy/sstirling.htm
http://www.fieldlines.com/story/2004/12/12/181043/68
http://www.engin.swarthmore.edu/acad...osal/FK_AO.pdf
http://www.ornl.gov/~webworks/cppr/y2001/rpt/27113.pdf

Anthony

DGG (in ) said:

| Not having kept up with the past history of this project, am I
| correct in assuming that this is to be used as a working fluid pump
| for a solar heating arrangement?

Actually, the project started out to be a desktop stirling engine -
then suffered considerable "scope creep".

I produce and (try to) sell passive solar heating panels; and so have
developed an interest in solar energy as a substitute for more
expensive energy sources. I haven't followed many of those interests
because of R&D costs. I have a particular fondness for mechanisms with
no moving parts to wear out and which can be made to exhibit "smart"
behaviors.

Anyway, once the little desktop engine was running, I wondered if it
could be made useful by growing it larger. The first application that
struck me as really suitable was the pumping application. I figured
that if I could produce a useful and inexpensive pump that used only
solar energy and never wore out - and could be easily reproduced by
ordinary folks, it could maybe offer some improvement to quality of
life for a lot of people.

It /could/ be used as a circulator pump as part of a solar heating
system. Since I'm looking for maximum impact, I decided to first take
aim at irrigation and village water supply applications - they're not
terribly demanding and would probably benefit the largest number of
people in the most significant manner.

One of the interesting characteristics of the stirling cycle is that
it is reversible - if, instead of putting heat in and getting work
out, you put work in then you'll see the engine work as a heat pump:
one side will get hot and the other cold (obviously, I'm one of the
"easily amused"). Once a full-sized pump is working, I plan to hook
two of these things together back-to-back and see if I can convince
the second engine to work as the heart of a solar refrigeration/air
conditioner. If I can manage that, people in remote areas without
electricity can have free (meaning "no operating cost") refrigeration;
and people in Arizona, New Mexico, and Texas can have similarly free
air conditioning whenever the sun shines.

Just these first two applications seemed to justify whatever effort is
necessary.

| And since you seem to have experience along these lines, an
| additional question. I have looked at the large solar water
| heating panels on a few homes, and have always felt that due to a
| reduction in exposed surface area (thermal loss) that a tracking
| parabolic reflector focused on a small cylindrical "boiler" would
| be more efficient than the large panel designs. Is this, in fact,
| the case? Or am I dreaming again - I haven't kept up with changes
| in this technology in 19 years.

I can give you a most definite "maybe". The collector is only one
component of a complete system. My rule of thumb is that large
temperature differentials relult in "lossy" (less inefficient) systems
unless the system really requires high temperatures. In general, you
want the most energy (heat) you can get with the lowest possible
temperature differential. It's _really_ important to not confuse heat
with temperature.

| My other quandary is, "How the heck do you find time and enthusiasm
| to pursue all of this stuff?"

I like people: enthusiasm is always a choice - I /make/ time for the
things I think worthwhile. Sometimes it's not easy.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

Wed, Oct 11, 2006, 5:31am (EDT-1) (Morris*Dovey) doth
off-topically posteth:
I've just added the first photos to my solar stirling web page snip

Hi ya Morris. Thenks for the link. LMAO Not entirely certain
you're on the right path, but what the heck, few of us are. I tak it
you want a "solar pump" type of thing. Somewhere I have seen an article
on a solar type pump, supposedly steam powered. I've got the article
around somewhere, don't even dream I can find it, or weould ven look. I
don't remember details, but I guess the system works, used for
irrigation, somewhere in the mid-east if I recall right. The reflectors
seemed similar to what you're doing, but mor of 'em. Of course, that
could be because the system was so much larger. Didn't pump a huge
amount of water, but steady - as long as the sun ines. The reflector(s)
also had a plastic, or glass, cover. Dunno what a DAGS would turn up,
it just popped up in my mind, so may, or not, try one.

In the meantime, I just ran across this link to a museum quality
Stirling, that may help you.
http://dailydiy.com/2006/10/10/boyds...t-air-engines/



JOAT
It's not hard, if you get your mind right.
- Granny Weatherwax

J T (in ) said:

| Hi ya Morris. Thenks for the link. LMAO Not entirely certain
| you're on the right path, but what the heck, few of us are. I tak
| it you want a "solar pump" type of thing. Somewhere I have seen an
| article on a solar type pump, supposedly steam powered. I've got
| the article around somewhere, don't even dream I can find it, or
| weould ven look. I don't remember details, but I guess the system
| works, used for irrigation, somewhere in the mid-east if I recall
| right. The reflectors seemed similar to what you're doing, but more
| of 'em. Of course, that could be because the system was so much
| larger. Didn't pump a huge amount of water, but steady - as long
| as the sun ines. The reflector(s) also had a plastic, or glass,
| cover. Dunno what a DAGS would turn up, it just popped up in my
| mind, so may, or not, try one.

Yup - followed your link and the links on the web page. The problem
with the usual stirling engine (power piston and displacer piston
connected to a common crank 90 degrees apart) is that they require
costly machining and/or aren't readily scalable to produce really
useful amounts of power. Building a tin can engine to operate in the
kW power range looks pretty iffy.

The object is to work out a design that can be built inexpensively,
require no fuel or electricity, will run reliably over a long period
of time with little or no maintenance, and deliver at least 2hp.
Scalability (the ability to do more work with a larger version of the
same design) would be a major plus. I'm trying to design the pump so
that anyone who can cement two pieces of PVC pipe together can build
one for themselves.

The trough shouldn't require much in the way of woodworking skill to
build; and the "plumbing" between the trough and the stirling isn't
critical (and doesn't even need to be leakproof.)

I don't know that I'm the right path, too; but it's the best I've been
able to manage so far. I had some ideas last night for an
easy-to-build (hacksaw only) multi-stage regenerator that might (or
might not) make this design a lot more efficient by capturing a part
of the heat used in each cycle and recycling it for use in powering
the next cycle. It's one of those "why didn't I see this from the
beginning?" kinds of things...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

Anthony Matonak (in )
said:

| Have you looked at other peoples liquid piston stirling pumps?
|
| http://www.linux-host.org/energy/sstirling.htm
| http://www.fieldlines.com/story/2004/12/12/181043/68
|
http://www.engin.swarthmore.edu/acad...05_6/E90Propos
al/FK_AO.pdf
| http://www.ornl.gov/~webworks/cppr/y2001/rpt/27113.pdf

Anthony...

I've looked at some - but none as informative as either the Swarthmore
or Oak Ridge documents.

Thanks for the links!

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

I like the idea of running a pump. One of the links showed water pumping where
there is no other source of power. This could be a real plus to people that live
in remote places and need water pumping. One of the things people mention when
they put in water pumping in third world countries is, "who will maintain the pumps?".
Anything that is simple and self sustaining would be much better for those conditions.


"Morris Dovey" wrote in message ...
I've just added the first photos to my solar stirling web page -
showing an electrical (resistance) heater being used for testing and
the early construction of the wooden prototype parabolic trough frame.

As promised, progress is slow and jerky - but the engine appears to
scale nicely (the most recent engine has a stroke of ~5" with 30W
input).

Many thanks to all who've offered encouragement!

More later...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

Wed, Oct 11, 2006, 8:30pm (EDT-1) (Morris*Dovey)
doth mumbleth:
Yup - followed your link and the links on the web page. snip
The object is to work out a design that can be built inexpensively,
require no fuel or electricity, will run reliably over a long period of
time with little or no maintenance, snip

Yeah, but you've gotta admit, that Stirling is definitely museum
quality. LOL
And, no, I don't think you'd get anywhere with a tin can Stirling.
However there used to be some hot-air engines that could do some serious
work. But, I don't think they'd be what you're after here.

What you want is something like a hydraulic ram, no moving parts.
There's also a propane powered outboard based on that - that one I don't
think you need. The hydaulic ram would need a moving source of water
tho, and I don't think you'd have that. Seems to me that I've read
somehing about something that's along t he lines of a hydraulic ram that
you could use, but I can't remember what or where. No way could one put
out your 2hp, but make multiples instead and that would work.

I'm thinking what you want to do has already been done. But where
I've seen something you can use, I don't remember. However, I used to
check out a lot of NASA inventions, and it seems to me I may have seen
something there. It'd be in the public domain. I don't think you'd
want to scale up, I think adding units until you get what you want/need
would be preferred.

How igh do you want to lift? A series might work best. With
multiples efficiency wouldn't be as much of an issue. Ever see a
river-powered water wheel, for irrigation? It might only lift a cup of
water with each "bucket", but with a lot of buckets, and continual
operation, it can pump a huge amount of water. I've seen 'em made with
an old wagon wheel, and some out of just bamboo - not very high tech,
but they all worked.

Hmm, somewhere in the filing cabinet of my mind, I've got the
feeling you're close, but not quite the right path. Been a long time
since I was interested n stuff like this, and I'm not sure how much of
my reference material I have left. Seems like one of the gubmint
organizations to help underdeveloped countries may have something
that'll work for you. I'll keep pondering a bit on this, and maybe see
what reference material I have left. If I come up with something
concrete I'll make you a good price on it. LOL



JOAT
It's not hard, if you get your mind right.
- Granny Weatherwax

SJC (in wR6Xg.8519$ji5.3676@trnddc04) said:

| That is a nice sized trough, it should produce good heat.

My compadre in this project took the first temperature measurements
this afternoon. The results weren't too bad - more photos added to the
same web page (link below).

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/StirlingProject.html

I have used a 20" x 48" trough with 3/4" copper tube in a 1 1/2" glass tube.
The glass tube made a lot of difference reducing heat loss.

"Morris Dovey" wrote in message ...
SJC (in wR6Xg.8519$ji5.3676@trnddc04) said:

| That is a nice sized trough, it should produce good heat.

My compadre in this project took the first temperature measurements
this afternoon. The results weren't too bad - more photos added to the
same web page (link below).

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/StirlingProject.html

--You should post the link to rec.crafts.metalworking as there are
quite a few Stirling and solar nuts over there, me included! ;-)

--
"Steamboat Ed" Haas : Proud to be the
Hacking the Trailing Edge! : family crackpot!
www.nmpproducts.com
---Decks a-wash in a sea of words---