Fluidyne well pump (5m)
Morris Dovey
at http://www.iedu.com/DeSoto/Projects/Stirling/ for anyone who might be
interested) and last night I made a conceptual sketch of a fluidyne well
pump and thought I'd post it, hoping that folks here might be able to
spot at least obvious problems.
I've drawn it to scale, with a 100 mm bore fluidyne engine - and with 50
mm water pipe extending to a depth of 5 m. I've uploaded the sketch to
http://www.iedu.com/DeSoto/Projects/Stirling/5mPump.jpg and plan to
rework as needed (your critique will help!) and incorporate into a web
page if/when I can arrive at something that should work. Please keep in
mind that I'm not a pump expert but am eager to learn. :)
The check valves are located halfway between the surface and the bottom
of the well pipe, with the hope that this arrangement will help avoid
pulling sand/rocks into the check valves.
The loop of pipe on the pump side is an attempt to avoid drawing air
into the engine if/when the well pipe drains.
Your comments will be much appreciated!
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/
Morris Dovey
> I've been tinkering with fluidynes (there's some background info on-line
> at http://www.iedu.com/DeSoto/Projects/Stirling/ for anyone who might be
> interested) and last night I made a conceptual sketch of a fluidyne well
> pump and thought I'd post it, hoping that folks here might be able to
> spot at least obvious problems.
It would seem that no one has spotted any obvious problems, so I cleaned
up the drawing a bit, and incorporated it into a new web page at
http://www.iedu.com/DeSoto/Projects/Stirling/5mPump.html
with some descriptive info and advance credit for the group who'll be
doing the work of building and installing the first one. When they
become available I'll add photos and installation/operation notes.
Axel Grease
news:ha7tqt$dn2$1...@aioe.org...
> Morris Dovey wrote:
>
I looked at your parabolic mirror on <
http://www.iedu.com/DeSoto/Projects/Stirling/Heat.html >
What kind of clear cover will protect the mirror from dust, rain, bird
droppings, errant children and their toys but also permit a sufficiently
high transmission of light to the mirror?
Axel
Axel Grease
/
Morris Dovey
Good question. In my area dust, snow, high winds, and hail are the
problems of greatest interest, and I've given serious thought to a
"mirror garage" into which the mirror can be retracted when it might be
at risk.
These things need to be well away from children - to protect the
children rather than the collector. The danger of severe burns and
damage to eyesight makes concentrators a bad choice where children will
be in close proximity.
At http://www.iedu.com/DeSoto/Projects/Stirling/HTAbsorber/ you can see
one of my attempts to deal with the "bright" problem, but that solution
actually worsens the burn potential.
I think that many commercial installations simply leave the mirror
unprotected, rotate them out of the weather when necessary, and do
periodic off-hour cleanings.
So far, the birds seem to prefer my car to the collector as the
dive-bombing target of choice. :(
Axel Grease
Referring back to your September thread about reflected light waste ...
It occured to me that a "quick-n-dirty" way to increase collection surface
area on the target pipe and to reduce reflected light waste, one might try
simple/cheap approaches like these:
- Knurl the pipe in a lathe to increase the surface area. You might want to
experiment with fine vs. coarse vs. a duplex knurling (fine knurling over a
prior coarse cut) to maximize the surface area increase.
- Parkerizing (phosphatizing) to achieve a flat, dark gray finish.
- Add a thinned out, flat green stain to increase UV absorption. (Green
used to be considered as better for UV abosrption than plain flat black. Is
that still the case?)
- One might then coat it with a flat, clear-coat (urethane?) to inhibit
rusting while still allowing the UV to find the green-black UV absorptive
coating.
What do you think?
Axel
Morris Dovey
I'm going to take the approach I described at
http://www.iedu.com/DeSoto/Projects/Stirling/HTAbsorber/
Note that it isn't the increase in surface area (although that's one of
the side effects), but rather using a surface geometry that guarantees
more reflections. It's important to keep in mind that we're after an
"optical" effect.
I thought about knurling, and decided that I couldn't maintain the
precision I needed that way.
The approach I've settled on for the time being is to re-grind a 3-inch
carbide slitting saw to cut a 10� V-groove as shown in
http://www.iedu.com/DeSoto/Misc/Saw10.jpg
and make repeated passes cutting each groove 1/32" (0.79375 mm) deep.
This geometry should yield 18 reflections for somewhere around 95%
absorption.
I haven't worried much about coatings other than to give a bit of
thought to taking the grooved tube to a printed circuit manufacturer for
a /very/ thin gold plating to inhibit oxidation of my aluminum tube.
I think it'll work well without any other coating.
Axel Grease
Interesting. Since the system will contain super-heated steam/water (and
not knowing the presures to be generated), I had not considered aluminum
tubing as the collector tube material. I presumed steel would the the
material of choice. Perhaps I am a bit old fashioned. Oh well. I have not
played with such things since the early '70s.
I was a devout fan of the Whole Earth Catalog and Mother Earth News... then
the international yo-yo effects of economic power games coming from Big Oil
and their pals in OPEC messed up so many good ideas.
Axel
Morris Dovey
> Interesting. Since the system will contain super-heated steam/water (and
> not knowing the presures to be generated), I had not considered aluminum
> tubing as the collector tube material. I presumed steel would the the
> material of choice. Perhaps I am a bit old fashioned. Oh well. I have not
> played with such things since the early '70s.
I'm only heating air (not under pressure) - so I don't need to worry
about anything other than exceeding the melting point of the aluminum.
For steam generation it'd a good idea to know a /lot/ more than I do. :-|
> I was a devout fan of the Whole Earth Catalog and Mother Earth News... then
> the international yo-yo effects of economic power games coming from Big Oil
> and their pals in OPEC messed up so many good ideas.
I enjoyed reading both (to the extent of buying a lifetime subscription
to TMEN when it was offered) but they did themselves in with really poor
financial management - worse, they put out a /lot/ of half-baked and
misleading information.
Most of their good ideas were premised on availability of a substantial
amount of discretionary time made possible by single-earner households.
When we, as a society, decided to effectively double the labor force we
produced major unintended consequences, and just a few of those were
elimination of a very large part of that discretionary time, a huge
increase in transport resource requirements, and serious reductions in
both quality and quantity of parenting. I'll own up to my share of the
responsibility for that decision, but I'm not as proud of it as I'd
thought I would be. It seems we achieved gender equality at the cost of
generational equality (and not just for a single generation).
The petroleum folks /are/ greedy, but no more so than they've always been.
sno
I have always thought the two earner household came about because of the
introduction of computers...and the movement from manufacturing to svc
economy.....causing not enough high paying jobs for one earner to
support a 4 person household....
If what I think is true there are going to be a lot more welfare people
in the future....as we are starting to see now...with people losing
their jobs and their savings.....
Do not see how we can exist with only poor and rich left...with few in
the middle class....
thank you for listening to my thoughts.....sno
--
Correct Scientific Terminology:
Hypothesis - a guess as to why or how something occurs
Theory - a hypothesis that has been checked by enough experiments
to be generally assumed to be true.
Law - a hypothesis that has been checked by enough experiments
in enough different ways that it is assumed to be truer then a theory.
Note: nothing is proven in science, things are assumed to be true.
Robert Scott
>Note that it isn't the increase in surface area (although that's one of
>the side effects), but rather using a surface geometry that guarantees
>more reflections. It's important to keep in mind that we're after an
>"optical" effect.
I've been wondering about this method. On one hand having a groovy surface
increases the chance, as you say, for multiple reflections and heat conversion
at each reflection. However a groovy surface also by necessity has a longer
average thermal conduction path before the heat can be carried away to do some
good. The bottom of the groove is nice and close to the collection fluid (or
air), but the peaks of the grooves are further away, and any heat collected near
the tips of these peaks has to travel lengthwise through the peak. This means
the average surface temperature will be higher, increasing conduction and
re-radiation losses. How does one go about measuring which of these two effects
is stronger?
As for optical measurements, how about using a photographic light meter to
measure the "brightness" of the collector in full sun? If the grooves are doing
any good, the light meter should register less light than from a flat black
surface. Or just look at it with your eyes. Set a flat black panel next to a
grooved panel in direct sun and see which panel looks darker.
Robert Scott
Ypsilanti, Michigan
Axel Grease
> Axel Grease wrote:
>
> > Interesting. Since the system will contain super-heated steam/water
(and
> > not knowing the presures to be generated), I had not considered aluminum
> > tubing as the collector tube material. I presumed steel would the the
> > material of choice. Perhaps I am a bit old fashioned. Oh well. I have
not
> > played with such things since the early '70s.
>
> I'm only heating air (not under pressure) - so I don't need to worry
> about anything other than exceeding the melting point of the aluminum.
>
> For steam generation it'd a good idea to know a /lot/ more than I do. :-|
>
Ahhh. Sorry. I have been missing a critical point and made an invalid
asumption about which media you are trying to use. I better understand what
you are up to now... making hot air... not hot liquids. That makes a lot
of difference. That approach was abandonded early-on back in the 70s.
Gasses (mostly air) , as a transfer media, were generally viewed as too
lacking in concentrated mass to be efficient. It took took much air flow
(or compression problems) compared to the return in transferrable BTUs...
even when using a FREE power source (Sun/UV). Gasses have too much
*insulation* (space) between the molecules to lend themselves to rapid
heating by concentrated forms of *insolation* (I know you will understand
the difference, Mr. Dovey, but other readers need those 2 spellings pointed
out.).
Due to their inherant densities, pumping liquids through a heat gathering
tube always gave better results.
> > I was a devout fan of the Whole Earth Catalog and Mother Earth News...
then
> > the international yo-yo effects of economic power games coming from Big
Oil
> > and their pals in OPEC messed up so many good ideas.
>
> I enjoyed reading both (to the extent of buying a lifetime subscription
> to TMEN when it was offered) but they did themselves in with really poor
> financial management - worse, they put out a /lot/ of half-baked and
> misleading information.
Yes. The early days of Mother Earth News magazine were much better than the
latter years.
But with discretion, one could still learn about some superb products. One
of my favorites was PermaChink... an acrylic chinking material for log
homes. Great stuff.
> Most of their good ideas were premised on availability of a substantial
> amount of discretionary time made possible by single-earner households.
> When we, as a society, decided to effectively double the labor force we
> produced major unintended consequences, and just a few of those were
> elimination of a very large part of that discretionary time, a huge
> increase in transport resource requirements, and serious reductions in
> both quality and quantity of parenting. I'll own up to my share of the
> responsibility for that decision, but I'm not as proud of it as I'd
> thought I would be. It seems we achieved gender equality at the cost of
> generational equality (and not just for a single generation).
O/T and disasterously sad, but interesting...
I remember the dying days of the single-earner family... the 1960s. Our
society did less deciding (implies a reasonable amount of high level
thought process) than you describe. They passively made a fatal error...
letting the mass media think for them... particularly in the case of TV.
Americans never quite "got it" that TV really has only one goal... to "sell"
goods and ideas. It became a stupendously sucessful propaganda dispenser
and sloth promoting sytem ever developed. Americans were ignorant and
gullible enough to swallow the garbage spewed through TV... hook, line, and
sinker... miserably and lazily squandering their brain power and
discretionary time by watching cartoons, sitcoms, and soap operas instead of
inventing and building toward a better future. Even people who saw
themselves as intelligent and choosey by watcing travelogues, News, and
documentaries were essentially wasting their lives whenever the television
droned on in front of them in their favorite couch or easy chair.
As Dinah Shore used to sing - "See the USA in your Chevrolet".
What she did not sing was - "That will make oil companies and politicians
powerful enough to enslave you while TV keeps your mind asleep ... idle
instead of working to find better alternative fuels. Watch TV long enough
and you will soon lose the knowledge, intelligence, and the FREE WILL to use
any of them."
But that didn't rhyme, so I suppose Dinah would never have be allowed to
sing that.
Axel
Morris Dovey
> On Tue, 13 Oct 2009 10:35:51 -0500, Morris Dovey <mrd...@iedu.com> wrote:
>
>> Note that it isn't the increase in surface area (although that's one of
>> the side effects), but rather using a surface geometry that guarantees
>> more reflections. It's important to keep in mind that we're after an
>> "optical" effect.
>
> I've been wondering about this method. On one hand having a groovy surface
> increases the chance, as you say, for multiple reflections and heat conversion
> at each reflection. However a groovy surface also by necessity has a longer
> average thermal conduction path before the heat can be carried away to do some
> good. The bottom of the groove is nice and close to the collection fluid (or
> air), but the peaks of the grooves are further away, and any heat collected near
> the tips of these peaks has to travel lengthwise through the peak. This means
> the average surface temperature will be higher, increasing conduction and
> re-radiation losses.
Excellent observation! The behavior will be strongly affected by the
particular geometry used...
A 180� groove (which isn't really a groove at all, but represents one
extreme fairly well) will both reflect and re-radiate a large portion of
the incident energy.
The number of reflections is determined by dividing 180� by the groove's
interior angle, and the only limit on "smallness" of the interior angle
is production technology. For sake of discussion let's consider the
opposite extreme to be 1�.
With a 1� interior angle we get 180 reflections, which should result in
some fairly awesome absorption - but look what else happens...
[1] Since re-radiation from the surface is omni-directional, nearly all
of the re-radiated energy will be directed toward the other side of the
groove, and very little will be directed outside the groove.
[2] Although the initial reflections will be distributed more or less
equally across the width of the groove, the subsequent reflections will
take place progressively deeper in the groove, with the largest number
of reflections closest to the "bottom" - and so with the shortest path
to the collection media.
[3] If the collection takes place in an atmospheric environment (as
opposed to vacuum), there should be a maximally "helpful" boundary layer
(actually a /pair/ of overlapping/intersecting layers) to inhibit
convective losses.
I think the interior angle and depth of the groove will determine how
pronounced each of these effects actually is.
> How does one go about measuring which of these two effects
> is stronger?
For me, the easiest way will be to build two troughs and equip one with
a plain tube and one with a grooved tube - and then take temperature
measurements of the inside of each tube. Once that's done, I'll swap the
tubes and do it again to reconcile reflector differences. It's a "poor
man" solution, but I think it'll do for my purposes.
It's important to keep in mind that only the boundary layer effect is
dependent on groove scale. If length of the conduction path is a
significant factor, it can be dealt with by making the grooves less deep
(consider a surface with grooves only 0.001 mm deep... :) )
> As for optical measurements, how about using a photographic light meter to
> measure the "brightness" of the collector in full sun? If the grooves are doing
> any good, the light meter should register less light than from a flat black
> surface. Or just look at it with your eyes. Set a flat black panel next to a
> grooved panel in direct sun and see which panel looks darker.
I'm hoping to be able to machine 10� grooves to capture (a guesstimated)
95% of a (calculated) 115-sun intensity, so I'd still be looking at 5-6
suns worth of radiation... I think I'd better stick with my cheap little
IR thermometer. :)
This method is (I think) only practical for concentrating collectors.
There is at least one method of achieving the same kind of efficiencies
for air and water flat panel collectors that doesn't involve anywhere
near the same production cost.
Morris Dovey
> Ahhh. Sorry. I have been missing a critical point and made an invalid
> asumption about which media you are trying to use. I better understand what
> you are up to now... making hot air... not hot liquids. That makes a lot
> of difference. That approach was abandonded early-on back in the 70s.
> Gasses (mostly air) , as a transfer media, were generally viewed as too
> lacking in concentrated mass to be efficient. It took took much air flow
> (or compression problems) compared to the return in transferrable BTUs...
> even when using a FREE power source (Sun/UV). Gasses have too much
> *insulation* (space) between the molecules to lend themselves to rapid
> heating by concentrated forms of *insolation* (I know you will understand
> the difference, Mr. Dovey, but other readers need those 2 spellings pointed
> out.).
> Due to their inherant densities, pumping liquids through a heat gathering
> tube always gave better results.
No worry - I hadn't made a point of /what/ I was heating; and the method
should provide the same advantages for heating water or oil.
My initial projects all involve providing heat for liquid-piston
Stirling engines in a context where cost and (apparent) simplicity have
a much higher priority than efficiency - in a development context
limited to woodworking tools and and an average budget of (typically)
less than US$2/day. My CNC router can cut decent grooves in aluminum
(but not in iron or steel) so I'm working with aluminum. :)
Originally I thought I might try using flat panel collectors, but the
Carnot efficiency (E <= 1 - Tc/Th) was so terrible that I decided to
switch to concentrating collectors which would deliver the same amount
of energy, but at a much higher temperature.
Heh - then I realized how inefficient my concentrator was due to the
(what should have been obvious) reflection, convection, and re-radiation
losses. I spent a couple of days being really unhappy about it all, and
then had this idea for improving the collector efficiency.
Fortunately, I don't need rapid heating and the aluminum/air transfer
approach seems adequate for the application.
When it finally soaked in that I had, perhaps, an improvement that might
be applied to more systems, and kinds of systems, than I was working on
I was pretty pleased with myself and all the folks here in
alt.solar.thermal who were willing to remain patient while I asked my
stupid physics questions.
I know more than I understand, but that's not new. :)
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
Robert Scott
>The number of reflections is determined by dividing 180� by the groove's
>interior angle, and the only limit on "smallness" of the interior angle
>is production technology. For sake of discussion let's consider the
>opposite extreme to be 1�.
If you are using angle of incidence = angle of reflection, then I think you are
talking about a mirror finish. A typical flat black paint will "reflect" is
just about every direction at once, regardless of the angle of incidence. Of
course more light will reflect at the "mirror angle", but a significant amount
of light will go straight back at the sun, unless you have a mirrored surface.
So talking about "capturing" all those reflections is a little unrealistic.
Also, there is little advantage to having more than a few "reflections". If
your surface is nice and black, it will retain at least 80% of the energy on
every reflection. So after 2 reflections, only 4% of the energy remains as
light. After 3 reflections, it is down to 0.8%, and after 4 reflections, only
0.16% of the original incident energy is still bouncing around as light. So why
bother talking about 180 reflections when there is essentially nothing left to
collect after 4 reflections?
>[1] Since re-radiation from the surface is omni-directional, nearly all
>of the re-radiated energy will be directed toward the other side of the
>groove, and very little will be directed outside the groove.
So you already realize that this reflection is not mirror-like.
>
>[2] Although the initial reflections will be distributed more or less
>equally across the width of the groove, the subsequent reflections will
>take place progressively deeper in the groove, with the largest number
>of reflections closest to the "bottom" - and so with the shortest path
>to the collection media.
Again, number of reflections means nothing without taking into account how much
is still left. I think most of heat will be deposited near the peaks - because
they have a clearer view of the sun than those deep valleys.
>It's important to keep in mind that only the boundary layer effect is
>dependent on groove scale. If length of the conduction path is a
>significant factor, it can be dealt with by making the grooves less deep
>(consider a surface with grooves only 0.001 mm deep... :) )
But grooves only 0.001 mm deep mean that peaks are only 0.0001 mm wide, and the
heat has to travel down those peaks.
>I'm hoping to be able to machine 10� grooves to capture (a guesstimated)
>95% of a (calculated) 115-sun intensity, so I'd still be looking at 5-6
>suns worth of radiation...
I don't know where you get the 5-6 suns. Through one square meter there is only
1366 watts of solar energy - no matter how you choose to collect it. Unless the
5-6 suns is the result of concentrators - in which case the effective apperature
of the collector is increased by those concentrators, not by the grooved target.
Robert Scott
Ypsilanti, Michigan
Morris Dovey
> I have always thought the two earner household came about because of the
> introduction of computers...and the movement from manufacturing to svc
> economy.....causing not enough high paying jobs for one earner to
> support a 4 person household....
That wasn't what I observed (as a computer guy). I saw a shift of focus
from the value women brought in the traditional homemaker role to the
value of the paycheck they brought home - a shift that appeared to me to
be promoted almost entirely by women. No one likes to be (or appear to
be) lacking value, and the transition seemed (in terms of societal
change) almost abrupt. The number of people wanting jobs grew very much
faster than the number of jobs.
A scenario I observed at a couple of major firms was a freezing of wages
for existing jobs, and an effort to absorb the new labor (at lower wages).
Inflation was a balancing force (and ultimately peaked in double digits)
and things began to stabilize with wage dollars that had a significantly
reduced purchasing power. I'm sure I'm not saying this very well, but it
would seem that the real value of wages can't exceed the real value of
what's produced without destroying the production mechanism.
> If what I think is true there are going to be a lot more welfare people
> in the future....as we are starting to see now...with people losing
> their jobs and their savings.....
>
> Do not see how we can exist with only poor and rich left...with few in
> the middle class....
I think a large middle class reflects the ability of a society to
produce large real value. If we want a large middle class, then we will
need to find a way for all to be significantly more productive. If we
can not or will not, our situation cannot improve.
Morris Dovey
> On Wed, 14 Oct 2009 13:47:51 -0500, Morris Dovey <mrd...@iedu.com> wrote:
>
>> The number of reflections is determined by dividing 180� by the groove's
>> interior angle, and the only limit on "smallness" of the interior angle
>> is production technology. For sake of discussion let's consider the
>> opposite extreme to be 1�.
>
> If you are using angle of incidence = angle of reflection, then I think you are
> talking about a mirror finish. A typical flat black paint will "reflect" is
> just about every direction at once, regardless of the angle of incidence. Of
> course more light will reflect at the "mirror angle", but a significant amount
> of light will go straight back at the sun, unless you have a mirrored surface.
> So talking about "capturing" all those reflections is a little unrealistic.
I agree, which is why I presented it as an extremity.
>
> Also, there is little advantage to having more than a few "reflections". If
> your surface is nice and black, it will retain at least 80% of the energy on
> every reflection. So after 2 reflections, only 4% of the energy remains as
> light. After 3 reflections, it is down to 0.8%, and after 4 reflections, only
> 0.16% of the original incident energy is still bouncing around as light. So why
> bother talking about 180 reflections when there is essentially nothing left to
> collect after 4 reflections?
"Black" would be the result of no reflections or re-radiation
whatsoever. I assumed bare metal with no coatings at all, which (in my
admittedly limited experience) doesn't exhibit that behavior.
Check the second photo at
http://www.iedu.com/DeSoto/Projects/Stirling/HTAbsorber/
Why bother to talk about it? Because I wished to choose /some/ boundary
condition, and that was convenient.
>> [1] Since re-radiation from the surface is omni-directional, nearly all
>> of the re-radiated energy will be directed toward the other side of the
>> groove, and very little will be directed outside the groove.
>
> So you already realize that this reflection is not mirror-like.
I do, and I also understand that even with mirrors there is no perfect
reflecting surface.
>> [2] Although the initial reflections will be distributed more or less
>> equally across the width of the groove, the subsequent reflections will
>> take place progressively deeper in the groove, with the largest number
>> of reflections closest to the "bottom" - and so with the shortest path
>> to the collection media.
>
> Again, number of reflections means nothing without taking into account how much
> is still left. I think most of heat will be deposited near the peaks - because
> they have a clearer view of the sun than those deep valleys.
Ah, I'm afraid I must not have made clear that this absorber is intended
to be located at the focus of a concentrating collector, and you must
have missed the last drawing on the web page which shows how the problem
you cite doesn't exist. Sorry.
>
>> It's important to keep in mind that only the boundary layer effect is
>> dependent on groove scale. If length of the conduction path is a
>> significant factor, it can be dealt with by making the grooves less deep
>> (consider a surface with grooves only 0.001 mm deep... :) )
>
> But grooves only 0.001 mm deep mean that peaks are only 0.0001 mm wide, and the
> heat has to travel down those peaks.
Exactly so, shall we shorten them still more?
>> I'm hoping to be able to machine 10� grooves to capture (a guesstimated)
>> 95% of a (calculated) 115-sun intensity, so I'd still be looking at 5-6
>> suns worth of radiation...
>
> I don't know where you get the 5-6 suns. Through one square meter there is only
> 1366 watts of solar energy - no matter how you choose to collect it. Unless the
> 5-6 suns is the result of concentrators - in which case the effective apperature
> of the collector is increased by those concentrators, not by the grooved target.
Well my trough is 44" wide and focuses the incident light to a region
3/8" wide. Dividing 44 by 3/8 yields a concentration ratio of ~117. The
mirror will eat a small amount of that, so lets say that the intensity
of the light at the absorber is only 115-suns. If the absorber slurps up
the 95% calculated, then 5% of 115-suns is 5.75-suns, which actually
does fall into the 5-6 suns range. :)
If you'd like a look at the trough in question, there're photos at
http://www.iedu.com/DeSoto/Projects/Stirling/Heat.html
I'm not discussing the aperture, only the efficiency of the /absorber/.
Bruce Richmond
I think your timing is a bit off. The two earner household was firmly
in place during the 1960's before computers were all that common.
There were no PCs at that time, just mainframes. IMO the 2nd earner
was added so that the family could afford some of the upscale things
that they just couldn't afford on a single income. The service sector
was only able to grow after there was enough disposable income to
support it. The movement from manufacturing was not intentional.
Bruce
> If what I think is true there are going to be a lot more welfare people
> in the future....as we are starting to see now...with people losing
> their jobs and their savings.....
>
> Do not see how we can exist with only poor and rich left...with few in
> the middle class....
>
> thank you for listening to my thoughts.....sno
>
> --
> Correct Scientific Terminology:
> Hypothesis - a guess as to why or how something occurs
> Theory - a hypothesis that has been checked by enough experiments
> to be generally assumed to be true.
> Law - a hypothesis that has been checked by enough experiments
> in enough different ways that it is assumed to be truer then a theory.
> Note: nothing is proven in science, things are assumed to be true.- Hide quoted text -
>
> - Show quoted text -
Bruce Richmond
Accordint to your calculator program it should get about 85%. How are
you getting 95%?
Good to see you have come up with a way to make a tube. If you wanted
to try a finer pitch, like 4 deg included angle, the shop I work at
has wire EDM machines. The wire is .010" thick and can cut any shape
under CNC control.
The choice of aluminum is good for heat transfer.
> I haven't worried much about coatings other than to give a bit of
> thought to taking the grooved tube to a printed circuit manufacturer for
> a /very/ thin gold plating to inhibit oxidation of my aluminum tube.
>
> I think it'll work well without any other coating.
>
> --
> Morris Dovey
> DeSoto Solar
> DeSoto, Iowa USAhttp://www.iedu.com/DeSoto/- Hide quoted text -
Morris Dovey
> On Oct 13, 11:35 am, Morris Dovey <mrdo...@iedu.com> wrote:
>> The approach I've settled on for the time being is to re-grind a 3-inch
>> carbide slitting saw to cut a 10� V-groove as shown in
>>
>> http://www.iedu.com/DeSoto/Misc/Saw10.jpg
>>
>> and make repeated passes cutting each groove 1/32" (0.79375 mm) deep.
>> This geometry should yield 18 reflections for somewhere around 95%
>> absorption.
>
> According to your calculator program it should get about 85%. How are
> you getting 95%?
I used an absorption rate of 15% - I think the actual rate may be as
high as 20% so I split the difference between that and my original
(conservative) program default rate of 10%. The truth of the matter is
that until I can produce some actual test results, I won't really have
anything more than a guesstimate.
[ The 'angle' program allows entering a (percentage) absorption rate as
a command line parameter - and if none is entered it uses a default rate
of 10%. Once an angle has been decided upon, the 'grooves' program will
provide all of the production geometry. ]
> Good to see you have come up with a way to make a tube. If you wanted
> to try a finer pitch, like 4 deg included angle, the shop I work at
> has wire EDM machines. The wire is .010" thick and can cut any shape
> under CNC control.
Let's talk off-group about what's reasonably possible and about cost. I
need to do some preliminary testing with whatever I can manage myself,
but I'd really like to find out what's possible with real tooling.
Your mention of a 4� included angle has me drooling. As Rob Scott
pointed out, that may be well beyond the point of diminishing returns -
but even so, actual test data could not only confirm that, but allow
accurate performance prediction.
It'd also be good to know about other metals and alloys for applications
involving the higher pressures Axel mentioned.
Let's talk.
Axel Grease
at
> > has wire EDM machines. The wire is .010" thick and can cut any shape
> > under CNC control.
>
> Let's talk off-group about what's reasonably possible and about cost.
> Your mention of a 4� included angle has me drooling. As Rob Scott
> pointed out, that may be well beyond the point of diminishing returns -
> but even so, actual test data could not only confirm that, but allow
> accurate performance prediction.
>
> It'd also be good to know about other metals and alloys for applications
> involving the higher pressures Axel mentioned.
>
> Let's talk.
>
> --
> Morris Dovey
I do hope you guys delve into a high pressure / high return realm. If you
do, it would be quite interesting to see what you come up with. I'm deeply
interested in integrated systems using Geo-Thermal, Organic Waste
by-products, and Parabolic Solar collection farms.
I am hoping a significant portion of coal/gas generation could be replaced
(or cheaply added to) if those were applied properly.
Axel