Hydrodyne electrical generator.

Copied from the Facebook group:

• Morris Dovey Carnot
  cycle engine (and steam engines are such) efficiency depends only on
  the difference between hot side temperature and the cold side
  temperature, and the systemic losses. I'm exploring an (approximately)
  1100°F/600°C hot side and ambient
  temperature cold side to produce a pressure cycle inside the focal tube
  of a trough-type parabolic concentrator. The real challenge, as always,
  is to minimize the systemic losses. :-)
  
• Bert Van Kets I'm curious to where you guys will push this.
  Keep the group posted.
  
• Morris Dovey The
  plan is to push it until an 8x4 trough (~3m^2) can provide at least
  close to 1hp of pumping power, and then publish a HowTo document. You
  might get a better notion of where by parsing a (not yet complete) web
  page at http://www.iedu.com/DeSoto/Misc/Project.html
  and if you click on the "Fluidyne Menu" button and follow the "Going
  Global" link, you can see photos and videos of early engines and a pumps
  in operation. On the same page as the "Going Global" link is an
  invitation to form a team and join in the fun.
  
• Bert Van Kets ‎@Morris: Could you explain what you mean with "1HP
  of pumping power"? Is this potential energy or electrical energy?
  You got some interesting things going on. I'll keep an eye on your projects.
  
• Bankey Biharidassa ‎Morris Dovey
  for your "Objective 5: Adapt the solar engine for refrigeration" check
  out the electrolux camper fridge.. here you only need to heat the
  vaporasation element... I thought of it for a couple of years.. but
  because I don't have a fixed place and workshop I couldn't find the
  opportunity to experiment with it.. from the perspective I have it should be
  very simple to make these fridges work on solar heat..
  
• Morris Dovey ‎Bert Van Kets
  - Applied mechanical energy. There's no electrical energy needed for
  the pump. The engine converts heat to oscillating pressure (resulting in
  push/pull of a fluid piston) which is used to draw water from the
  source during half of the cycle, and to push it out of the pump during the
  other half of the cycle.
  Bankey Biharidassa
  - What you describe works well for some contexts, but not all. Stirling
  cycle engines (in general) are capable of operating in reverse - that
  is, if they are driven with mechanical energy, heat energy will be moved
  from the "hot" side to the "cold" side. (I understand that this is one
  of the ways used to produce cryogenic temperatures in laboratories.)
  What I propose is to drive one Stirling cycle engine with solar heat to
  produce mechanical energy, which is then applied to a second Stirling
  cycle engine to cause the second engine to operate as a heat pump. I am
  working with Stirling cycle engines with fluid pistons, and so this
  "coupling" of the two engines involves nothing more than a pipe
  connection...
  And yes, the concept and construction are perfectly simple - but producing
  a satisfactory design isn't. :-)
  
• Bankey Biharidassa ‎Morris Dovey:
  forgive me my ignorance..I'm just a technician, no high educated
  engineeer.. but all mechanical moving things have the habit to break
  down.. This is why I like the absorpsion (electrolux) fridges so much..
  they have no moving mechanical parts..
  they are also quite cheap in second hand market.. as far as I can see,
  the only adaption to make is a heatpipe from the solarcollector to the
  vaporising part of the fridge.... anyway.. just a suggestion..
  
• Morris Dovey ‎Bankey Biharidassa - I don't think we're in so
  much disagreement as you've supposed. :-)
  If you take the time to look at the web pages I suggested, you will see
  that the only parts in my engines are air, water, and the pipe or tubing
  within which they're contained - and I would expect all three to last for
  centuries, at the least.
  Air and water are (usually) non-toxic and non-polluting - and both are
  available everywhere at minimum cost.
  I have no problem with recycling old fridges - but I have some difficulty
  imagining where enough of them might be found to fill the needs of tens
  (or hundreds) of millions of homes and businesses.
  I mentioned context as a part of my consideration. My goal is to produce a design
  that can be locally fabricated in under-developed areas without any
  higher level of technology than, say, might be found in a good bicycle
  repair shop.
  I really do like heat pipes - but I like even better a design that makes
  inclusion of heat pipes unnecessary.
  
• Daniel Connell Hey
  Morris, good to see you here. I think the liquid piston Stirling really
  needs an animation before I or many others are really going to see how
  it works. I've got a bit more time for stuff now, if you send me some
  keyframe sketches or something that I can get my head round the thing
  I'll be able to do up a simple enough animation illustrating the cycle.
  Also definitely going to have to put a week or two aside and knuckle
  down on these sf tutorials...
  
• Morris Dovey Rather than an animation, you can watch a
  video of a small fluidyne running at
  http://www.iedu.com/DeSoto​/Fluidyne/Dyne.html
  but (from personal experience) watching only provides proof that
  they do work - and disappointingly little understanding of /how/ they
  work. For the how and why it's necessary to dig into physics/
  thermodynamics. I've tried to provide that at
  http://www.iedu.com/DeSoto​/Fluidyne/StirlingCycle.ht​ml
  but
  it takes a while for even that to begin to make sense. As I struggled
  to wrap my head around this stuff, I had to remind myself (continually)
  that if it were really easy, we'd have put these things to work a long
  time ago.
  I have many wonderful memories of Paris - and I hope you have time
  to relax and enjoy some of what the city has to offer.
  
• Daniel Connell Ahhhhh, I get it now. Nice tech.
  My
  father mentioned something interesting about getting electricity from
  fluid flows, I think it was something along the lines of ionising the
  fluid and passing it through a magnetic field, thereby extracting a
  portion of the kinetic energy.
  
• Daniel Connell Magnetohydrodynamics? I think it was?
  http://www.solarmhd.com/
  This
  would make of your fluid column a linear alternator, but without the
  frictional drag of solid magnets, tho there would be obviously
  resistance because you're taking energy out. Not sure how you'd treat
  the water or if you'd have to use a different fluid.
  
• Morris Dovey Interesting
  - especially so to me because if it works well, I just had a flash of
  insight as to how I might be able to substantially increase the
  electrical output. I need to think about this for a while... Thanks!
  
• Daniel Connell I'll get some more info off my father.
  
• Morris Dovey I'd appreciate that. I didn't expect to get this
  deep into all this in Solar Flower
  - my real reason for being here is to learn more about your elegantly
  simple tracking mechanism concept - and I apologize both for the
  distraction and for hijacking Gerald Good's turbine/generator thread.
  
• Daniel Connell Well
  now that the thing's tracking the next step is plugging it in.
  Applications need developing, and need to be the same kind of
  accessible, useful and free.
  So, no, this is good.
  
• Daniel Connell Hopefully soon have the website up, which will
  have a proper discussion forum.
  
• Morris Dovey To follow up on this aging thread...
  I just added a credit to you at http://www.iedu.com/Solar/​Engines/Hydradyne/
  - this is becoming more and more interesting/promising. :-) Thanks again!
  
• Daniel Connell Yeah nice, awaiting further details.
  I especially like how the thing can sit on the focal line of a trough...
  
• Daniel Connell Questions:
  What causes the oscillation in your double cold end hydrodyne?
  
  What kind of setup were you thinking for getting a field around this thing?
  
  How were you thinking to conductivise the water?
  
  Any ideas on numbers for overall efficiency, power etc?
  
  Anything
  you need to get this moving as quickly and easily as possible? This
  might do well in a crowdfunding type context, given the likely benefits
  of the outcome..
  
• Daniel Connell Also, 21718 kPa? Duuuuude...
  Plumbing copper will take twice that, but people are going to have to
  be _very careful with their soldering.
  
• Daniel Connell ALthough:
  http://bit.ly/oHpza5
  
• Morris Dovey With
  the right size passage between the hot and cold heads, the hot-cold
  head "interface" is astable (can't reach a stable equilibrium) and the
  result is a cycling between high (for some definition of high) and low
  (for some definition of low) pressure.
  In
  the double-headed critter, the path of least resistance is for the
  cycles to work cooperatively, so that while one end is producing a high
  pressure, the other end is producing a low pressure for half of the
  cycle, and vice-versa for the other half.
  My understanding is that
  it's sufficient to achieve a good level of ionization in the water, but
  (for example) a colloidal suspension of iron might work even better. I
  don't think the research has ever been done.
  Daniel, 22 MPa is closer
  to the pressure in a fully-charged SCUBA tank. I don't think ordinary
  copper plumbing will safely contain that - and if it lets go the steam
  explosion will be deadly.
  Do not solder! The engine will be operating at temperatures way above
  the melting point of solder.
  What would help? Hmm - I've wished that I could speak fluent technical
  Russian and Japanese (since these folks seem to be leading the MHD
  research). The project begs for real expertise in a number of fields
  that don't generally overlap, and for far better laboratory and
  prototyping facilities than are available even to most universities.
  If you (or anyone) wants to tinker with this stuff, I strongly advise
  starting with the low-pressure fluidynes and taking the time to learn
  and understand the physics/thermodynamics at each step.
  For anyone wanting to learn about the MHD power generation aspect,
  the best starting point I've found so far is:
  http://www-ferp.ucsd.edu/L​IB/REPORT/JOURNAL/MISC/McG​rawRev.pdf
  but I'll warn that it isn't an easy read.
  
• Daniel Connell ‎> I don't think ordinary copper plumbing will safely
  contain that
  
  Right,
  rechecked and I was totally reading the units wrong. Yes, it is in fact
  almost exactly ten times what a 22mm copper pipe will handle.
  Guess you're going with thickarse steel then? How will you get the heat in?
  Steel is a poor conductor...
  
  > and if it lets go the steam explosion will be deadly.
  
  Quite.
  
  > The engine will be operating at temperatures way above the melting
  point of solder.
  
  Depends on the solder. But I was thinking copper, guess with steel you
  can use threaded caps.
  
  > The project begs for real expertise in a number of fields that don't generally overlap
  
  The folks at http://cr4.globalspec.com/ would love this, and they know their stuff.
  
  > but I'll warn that it isn't an easy read.
  
  It isn't.
  
  So
  what's your likely timeline on this? It seems a good way forward,
  providing it can be brought down to the level of the home maker.
  Does the fluid need to be water? Is there something else which could
  be used at a lower pressure?
  

> take advantage of an absorption technique I worked out a while back

Not sure that's going to be a good idea. True that it will increase your captured heat, but matt black paint is already very low reflectance (about 3-5%) and this approach is going to cost you in terms of greatly increased surface area and metal thickness.
And if you're using stainless (about 10-20 times less conductive than copper), thickness is not what you want.
Vacuum tubes are getting pretty cheap, and are very effective.

> there's a lot to be figured out before it makes sense to get into the specifics of mechanical design.

I'm just used to approaching these things from the other end, starting with a palette of available materials and trying to force something functional out of it all. Not because this is a good way of doing things, just what doing the SF conditioned me into.

> some members of any open forum will attempt to grab and run

Ah so. Can you be licensing it as you go?

> might be built by anyone with good welding/brazing skills in a year.

The design seems fairly simple, tho obviously all I've seen is the one sketch, is this figure to get something basically functioning, or fully optimised?

> the MHD and associated electrical/electronic portion may require factory production.

Even for something that, again, basically functions?

At more than 200 suns black paint will appear blindingly white (that bright white is reflective loss), and at temperatures in the 600°C range it probably won't last very long. That's the "why" behind the effort to produce a better absorber technology.

Sometimes it works well to "just build the bugger" but if there're dangerous forces involved, it becomes worthwhile to exercise caution until everything is reasonably-well understood.

Wall thickness (and choice of material) will end up being whatever works and at the lowest cost that can be managed - but I'd rather be safe than sorry while there are so many unknowns. Let's get one working and then apply everything we've learned to reduce the cost.

I don't have the resources (time, energy, or financial) to screw around with licensing. Slapping a license on something is a whole lot different from enforcing them.

I love simplicity - especially efficient machines without moving parts! This technology is about as good in that regard as could ever be hoped for - but I've discovered that they're neither simple nor easy to design. I give you my absolute guarantee that if I could "just do it", I would have.

The MHD stuff is "sorta" understood. It's the reduction to practice that's difficult. My goal for the initial version is to use a 4x8 (feet, sorry) sheet of mirror material and some plumbing to produce a full 1 kW output, but there's nobody in the world who knows for certain that's possible. We're not stacking Leggos here, we're walking out away from the firelight to find what's hiding in the dark.

Now, aside from all that, it's the pump that's still my first priority. There are people dying, right now while I type, because they don't have water to drink and to grow food. No one is going to die because they don't have electricity to charge their iPad or cell phone - or even if they don't have electric lights in their classroom.

> (that bright white is reflective loss), and at temperatures in the 600°C range it probably won't last very long.

It's still only 5%, and high temp paint will take 600 C.
The star profile collector is a good idea tho, I'm not knocking it. Also, thinking about it, with a vacuum tube the surface area and conductivity shouldn't really matter, as both those things only add to back shedding of energy, which is impossible in a vacuum.

> Slapping a license on something is a whole lot different from enforcing them.

Indeed. What are your plans for the thing once it's going?

> My goal for the initial version is to use a 4x8 (feet, sorry) sheet of mirror material and some plumbing to
> produce a full 1 kW output

That's 30% overall.
Ye gods man, that's astounding.

> it's still the pump that's still my first priority.

Something that annoys me greatly about the fluidyne is that it's almost exactly what I spent two months in Spain and Germany trying to design, not knowing it already existed, as the pump mechanism for the solarflower's engine. Two freaking months. What I ended up with is slightly better for the application, but really wish I'd known about these things start of 2010.

Quick thought, how is MHD affected by a metal walled container?

Also, thinking about it, with a vacuum tube the surface area and conductivity shouldn't really matter, as both those things only add to back shedding of energy, which is impossible in a vacuum.

Re-radiation is also a significant loss mechanism. Let's just assume absorption and get on with the things we don't know so well. If the device can be produced, people will be motivated to do the work to improve absorption. :-)

What are your plans for the thing once it's going?

Drop it squarely into the public domain - my tentative strategy is to place the technology into the hands of an organization capable of and motivated to protect global free public usage rights. Having said that, I'll say no more.

That's 30% overall. Ye gods man, that's astounding.

It's not done yet, but it appears possible. Half of that would be still be good. I choose to aim high.

Two freaking months. What I ended up with is slightly better for the application, but really wish I'd known about these things start of 2010.

You should'a stopped by my web site. :-)

Quick thought, how is MHD affected by a metal walled container?

Adversely. MHD "heads" will need a pair of "flux windows" and a pair of electrodes insulated from the metal tube.

A quick postscript: For electrical power generation, we're talking about a "hydradyne" rather than a "hydrodyne".

> Half of that would be still be good.

It would be. Currently off the shelf steam and Stirling engines run to about 5-7% overall, so even mid teens would be a significant improvement.

> MHD "heads" will need a pair of "flux windows"

Made of what?
If MHD is going to be tricky in the build, what about a simple linear alternator in the form of a free floating magnet within the fluid, with a coil around the tube? Would need a 'flux window' and something basic to stop it from wandering...

Made of what?

Tempered glass or ceramics

If MHD is going to be tricky in the build, what about a simple linear alternator in the form of a free floating magnet within the fluid, with a coil around the tube?

If it weren't tricky, it'd already be done. Let's stipulate that we have somewhat to learn, and just get on with the learning process.

The rare earth elements for the magnets are already increasingly difficult to come by. I don't want a lab toy for my friends and neighbors to admire - I want a workhorse that can be replicated and put to work by the thousands or millions - and I want the engine/generator to have a service life of half a millenium.

I'm up for a bit of trickiness. :-)

That's a good level to be aiming for.

What do you think in terms of a more budget version, lower efficiency but easier to build, that could be developed in parallel with the gooder one?

What do you think in terms of a more budget version, lower efficiency but easier to build, that could be developed in parallel with the gooder one?

I don't think it's a good idea.

My focus will be on getting the first one working without producing any casualties.

The first will be the most expensive, and it'll cost whatever it costs.

I guess there is the reasonable danger of explosions causing death..

I guess there is the reasonable danger of explosions causing death..

Thank you for noticing - I would hate to lose my only NZ friend. :-)

I've been so pre-occupied with what it might take to get one of these to work that I hadn't begun a test plan or checklist. I just created a file "Solar/Engines/Hydradyne/TestPlan.txt" and the first lines under Ground Rules are Observe tests by video from safe location and Ensure that all tests can be safely aborted.

It's probably worth noticing ahead of time that a working engine may produce some serious vibration...

> Ground Rules are Observe tests by video from safe location and Ensure that all tests can be safely aborted.

If I'd taken that kind of rationale with the SF I would've missed some very pretty explosions and subsequent bench fires.

> a working engine may produce some serious vibration...

What's the frequency and stroke of the thing likely to be?

And what's the most basic mhd setup possible? Is it just a matter of running a conductive fluid through a coil, or is there trickiness involved?

If I'd taken that kind of rationale with the SF I would've missed some very pretty explosions and subsequent bench fires.

Umm - I'd fairly well gotten past finding explosions pretty by the time I'd completed my military service. If there's an explosion here there won't be any pyrotechnics - just a flash of steam and a shock wave, plus shrapnel.

What's the frequency and stroke of the thing likely to be?

TBD - that'll depend on the MHD. I think I can design frequency and stroke to suit needs but don't yet know what those needs are. I'm afraid that a lot the basic stuff I need to know may need to be discovered experimentally.

And what's the most basic mhd setup possible? Is it just a matter of running a conductive fluid through a coil, or is there trickiness involved?

Take a look at the drawing at the bottom of http://www.iedu.com/Solar/

Basically, we want a strong magnetic field perpendicular to the fluid flow (vertical in the drawing) to deflect ions right and left (horizontal in the drawing) to electrodes.

Conceptually, it's wonderfully simple. The headaches start as soon as I try to put numbers to any of the parameters, because some of what I need to know are answers to questions that apparently haven't been asked before or are being kept under wraps in commercial labs.

Most of the trickiness will be in designing experiments to remedy ignorance. It doesn't help a lot that I don't even know all the questions I need to ask.

Shrapnel does tend to put a nasty edge on things, yes.

So this image:

set it straight for me, and yeah it seems pretty simple.

How were you thinking to generate your magnetic fields? Electromagnets or solenoids I guess? Do you think speaker magnets would be strong enough? Easily scrappable...

Speaking of which, this is probably a spectacularly uninformed question, but would it be possible to grind speaker magnets into powder (which is basically what they are) and have that in a fluid flowing through a basic wire coil to generate current?

How were you thinking to generate your magnetic fields? Electromagnets or solenoids I guess? Do you think speaker magnets would be strong enough?

I would guess that electromagnets would be most economical, and that it would probably be worth experimenting with speaker magnets. I will guess that the stronger the magnetic field the greater the power output (more charge deflected to electrodes), and I suspect that top end speaker magnets make use of rare earth elements.

would it be possible to grind speaker magnets into powder (which is basically what they are) and have that in a fluid flowing through a basic wire coil to generate current?

Probably not because the poles associated with each particle would be randomly-oriented, so that any two particles with opposite orientation would cancel each other. In the unintended consequences department, the particles would attract each other and form clumps. Aside from those aspects, the particles/clumps would probably be pretty abrasive.

I suspect that the magnet and coil approach would work better with a single cylindrical magnet, but that approach also has drawbacks - not least of which is that that the engine would need to waste energy to overcome and reverse the inertia of the magnet twice in every cycle.

> I would guess that electromagnets would be most economical

Means having to energise your field tho, which means not self starting, less efficient, and more electronics.

> and I suspect that top end speaker magnets make use of rare earth elements.

They look (after a half hour research) to be ferric, and up to 1000 Gauss / 0.1 Tesla. Magnets out of hard drives, on the other hand, are rare earth and about 3-10 times stronger, however as they're much smaller the dropoff is a lot closer.
Could be the go tho, hdds are everywhere, and being so thin you could have the magnets inside your container...
They might even take the heat and pressure.

> the poles associated with each particle would be randomly-oriented

No chance the field would flip them as they passed through? Or would it flip them the wrong way..
Think I might let this idea go, sounds like something that someone who didn't go to university would suggest.

> the engine would need to waste energy to overcome and reverse the inertia of the magnet

But you'd get that back as it entered the field with more force, no?


I'm thinking of a kinda weird steam engine, one that creates a jet of it's own boiler water rather than a jet of steam, either for driving a water turbine or mhd gennie... in fact it's almost exactly the same kind of setup as the tracking motor for the SF, but hopefully a lot more powerful and efficient.
I'll get a sketch up.

Being weird tho, there's probably a reason it's not been done. I usually avoid that kind of thinking, but steam is a very tapped field after the last hundred years.

Means having to energise your field tho, which means not self starting, less efficient, and more electronics.

Yes, unless generated power can be used for the field. From descriptions of portable generators, I think it may be possible to retain enough magnetism in the core of an electromagnet to allow self-starting.

They look (after a half hour research) to be ferric, and up to 1000 Gauss / 0.1 Tesla. Magnets out of hard drives, on the other hand, are rare earth and about 3-10 times stronger, however as they're much smaller the dropoff is a lot closer. Could be the go tho, hdds are everywhere, and being so thin you could have the magnets inside your container...
They might even take the heat and pressure.

Ok. Give it a shot and let me know what you learn, :->

But you'd get that back as it entered the field with more force, no?

My guess would be 'no', but everything would hinge on whether it provided a net advantage over a superfluid MHD approach - so I'm stuck with having to admit that I don't have a clue. :-)

I'm thinking of a kinda weird steam engine, one that creates a jet of it's own boiler water rather than a jet of steam, either for driving a water turbine or mhd gennie... in fact it's almost exactly the same kind of setup as the tracking motor for the SF, but hopefully a lot more powerful and efficient.
I'll get a sketch up.

Being weird tho, there's probably a reason it's not been done. I usually avoid that kind of thinking, but steam is a very tapped field after the last hundred years.

There are a lot of things that don't operate the way our experience and intuition tell us they must - and we haven't yet explored all the nooks and crannies. If you have an idea, and can figure out some way to test it, you may be rewarded with a pleasant surprise - and if it turns out not to work, figuring out why may provide important clues about how to go about helping it to work.

I just added a not-to-scale concept sketch of a hydradyne engine with dual regenerator/MHD sections to the DeSoto Solar hydrodyne engine web page.