More Stirling Stuff

[Morris Dovey]

...or "Thinking weird thoughts in Iowa"

I got to wondering just how big a fluidyne I could build - after all, I've seen some pretty sizable plastic pipe going down the road on semis. Naturally, I ended up asking myself: "Well, if you could build a big honkin' Stirling engine, WTF would it ever be good _for_ ?

That evening I spotted a blurb about using windmills to produce power to run pumps to fill reservoirs for hydroelectric power generation when the wind wasn't blowing - !?! - and I had an application for my big engine.

I thought about it a bit more and decided that plastic pipe might not cut it for _really_ big engines - perhaps the pump bodies could be cast in place using reinforced concrete. I'm still mulling that one over...

Anyway, I've just put up another Stirling engine web page that goes a bit beyond the coffee cup scale. I think I'll take a swing at the hydroelectric generation idea myself. Link in my sig. Part of the prototyping done did actually involve woodworking.

I don't mind saying that I'm *way* over my head on this one (I've done that often enough that it doesn't scare me any more) so please feel welcome to throw corrections, better ideas, rotten veggies, at my mailbox.

Also let me know if you're aware of any good potential reservoir sites in Italy, Greece, Spain, Morocco, Portugal, Mexico, Ecuador, Turkey, California...

;-)

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[dpb]

...

"Pumped storage" facilities...not the _most_ widespread thing, but quite a number of them exist. W/ excess capacity at night, etc., can help on peaking by using that capacity to refill the reservoir when not needed on the grid. Aids in mitigating needing more capacity for peak demand...

Other than that, interesting thought, but no direct input (other than to note we have lots of wind generation here, but no hill nor (surface) water to pump... :)

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[Morris Dovey]

dpb wrote: | Morris Dovey wrote: || ...or "Thinking weird thoughts in Iowa" || | ... | || That evening I spotted a blurb about using windmills to produce || power to run pumps to fill reservoirs for hydroelectric power || generation when the wind wasn't blowing - !?! - and I had an || application for my big engine. | | "Pumped storage" facilities...not the _most_ widespread thing, but | quite a number of them exist. W/ excess capacity at night, etc., | can help on peaking by using that capacity to refill the reservoir | when not needed on the grid. Aids in mitigating needing more | capacity for peak demand... | | Other than that, interesting thought, but no direct input (other | than to note we have lots of wind generation here, but no hill nor | (surface) water to pump... :)

My guess is that (at least initially) the greatest interest in a lash-up like this might be on a mountainous coast in a location with a lot of sunshine.

It's interesting to me because the initial investment could be relatively small, the maintenance/upkeep requirements would be essentially those of providing TLC to the generators, and the (hydro)carbon cost would be zip.

In seacoast areas, the upper reservoir "head" might also serve reverse osmosis desalination facilities to provide freshwater in locations where it was scarce.

Grows more trees, lets more people work wood...

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[Han]

I just heard that some big office buildings save money on energy by freezing water at night and using it by day to cool air for air conditioning needs. What would be the requirements of fluidyne engines to generate cooling?

Han

[Morris Dovey]

| I just heard that some big office buildings save money on energy by | freezing water at night and using it by day to cool air for air | conditioning needs. What would be the requirements of fluidyne | engines to generate cooling?

Warning: I haven't tried cooling with fluidynes yet - and I'm not aware of anyone else ever trying. I'm giving you my best shot at what I think is a reasonable answer, but you should maintain some degree of scepticism...

To do the job with fluidynes alone, you'd need a pair of fluidynes and a source of heat to drive the first in "normal" mode, which would produce the mechanical energy to drive the second in "reverse" mode. It'd only be cost efficient if you had an economical source of heat.

As with other Stirling cycle engines, in normal mode fluidynes work off a temperature differential between their "hot" head and their "cold" head to produce mechanical energy...

...but/and one of the interesting characteristics of Stirling cycle engines is that if mechanical energy (instead of heat energy at the hot head) is applied, they'll respond by developing a hot side and a cold side.

[ I've actually driven a small mechanical Stirling engine with a drill and seen frost form on the cold side. I have no idea why it didn't occur to me back then to couple two of 'em together. I may be a bit slow on the uptake... ]

So I guess that the answer to your question is that if you have a source of alternating pressure, you can apply that to a single fluidyne to develop a hot side and a cold side. If you circulate water around the cold side and through a heat exchanger (picture an auto radiator) and blow air through that heat exchanger, then you have a fluidyne air conditioner.

If you lack a source of alternating pressure but do have an economical source of heat, then you can apply that heat to the hot side of another fluidyne and let it be the source of alternating pressure - the setup I described in my first paragraph.

There's a drawing of the two-fluidyne solution on the web page at the link below. I'm not a bit hesitant to confess that it looks almost too strange to be credible - and yet, I think it will work.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[J T]

Wed, Aug 15, 2007, 2:52pm (EDT-1) [e-mail] (Morris=A0Dovey) doth sayeth: ..or "Thinking weird thoughts in Iowa"

Well, if I was looking for a way to feed a resivor from a river, I'd just go with hydraulic rams.

If it all doesn't work out, here's something simple you can try instead.

JOAT I do things I don't know how to do, so that I might learn how to do them.

- Picasso

[Puckdropper]

"Morris Dovey" wrote in news:46c35a5a$0$3581$815e3792 @news.qwest.net:

*snip*

Morris, I've got some Sahara Swampland to sell you. ;-)

Puckdropper

[Morris Dovey]

| Morris, I've got some Sahara Swampland to sell you. ;-)

Valuable real estate! I think you'd better hang onto it - you're in position to dominate the north African cranberry market. :-D

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[Morris Dovey]

J T wrote: | Wed, Aug 15, 2007, 2:52pm (EDT-1) [e-mail] (Morris Dovey) | doth sayeth: | ..or "Thinking weird thoughts in Iowa" | | Well, if I was looking for a way to feed a resivor from a | river, I'd just go with hydraulic rams. | | If it all doesn't work out, here's something simple you can try | instead.

If you have the head to work with, the hydraulic ram might work for you.

Largely it's a matter of scale and moving water (a _lot_ of water - an average of 11 cubic km per day) uphill. It almost certainly won't be a single pair of reservoirs, and it'll take a lot of pumps.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[Scott Lurndal]

Morris,

Here's a local storage site:

scott

[Morris Dovey]

| Here's a local storage site: | |

- especially so since I've been in that neighborhood without even knowing it was there.

It looks as though they already have everything they're likely to want already in place - and also as if that water is fully committed for agricultural use.

I've saved the wikipedia reference so I can revisit. Thanks!

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[dpb]

Smith Mountain/Leesville Lake combined pumped storage facility (Appalachian Electric Power)

Smith Mountain, they drop into Leesville Reservoir for the reclamation and pump back in offpeak hours. Unfortunately, the Leesville lake is much smaller than Smith Mtn so they're limited in how much can generate before it is at limit stage...

Another I'm at least somewhat familiar with is TVA's Raccoon Valley.

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[Scott Lurndal]

A lot of that water goes to LA for lawn irrigation :-). The California aquaduct runs along I-5 there, and the Oneill forebay links up with it to deliver water to the overpopulated southern desert. They pump into San Luis in the winter and spring when the runoff from the Sierra Nevada is running, and release water in the summer and fall to LA (and the san joachin valley).

scott

[Morris Dovey]

| Smith Mountain/Leesville Lake combined pumped storage facility | (Appalachian Electric Power) | |

|| At Smith Mountain, they drop into Leesville Reservoir for the | reclamation and pump back in offpeak hours. Unfortunately, the | Leesville lake is much smaller than Smith Mtn so they're limited in | how much can generate before it is at limit stage... | | Another I'm at least somewhat familiar with is TVA's Raccoon Valley.

This comes a bit closer to the type of project I'm looking at, except that I'm aiming to pump the lower reservoir "dry" (with non-electric pumps).

They seem to like to put these things in (IMO) beautiful country.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[dpb]

Well, two things contribute to that...it takes the change in elevation which implies (usually) mountains and secondly, water. The combination of those makes for what most folks find "purty"... :)

Smith Mountain and Leesville are both constructed, of course. Smith Mountain in particularly is a very much used and developed property. When we were in TN it was almost new and fairly undeveloped. Lakefront property just seemed exorbitant, but if had bought some would have made a _very_ nice investment!

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