Design/Build One HP Alpha Stirling Engine

[Ferraccio]

Internal diameter of pipes/clearances interest all the sites of heat exchange, so in exchange tubes, but also in regenerator, that normally is done by thin wires meshes or stainless steel wool.
The "optimal clearance" (for every gas type) is obviosly the space fot the passage of the gas!!
And for gas is considered the "cicle gas" that is moved internally the engine.
External refrigeration/heating are another matter.

[Ferraccio]

Michael,
The picture by you proposed is a really intersting double acting, alpha tipe, four cylinders, engine.
The gas flow through the four cilinders.
The really interesting element is that the loop is very clean, the same functions as a displacer cylinder top, and bottom cylinder engine.
dead space is not very low.
The mechanism is not very complex and consists of four gears with a single axis motor output.
As for all other elements it is clear that regard the "passages" on the gas cyvcle, both through pipes than the mesh / sponge net of the regenerator (referrirring the commercial devices adopted, diameter of wire, gauze, etc); the regenerator, as you know, is the foundant element of the 1816 Stirling patent.

[Ferraccio]

I correct myself
Michael,
The picture by you proposed is a really intersting double acting, alpha tipe, four cylinders, engine.
The gas flow through the four cilinders.
The really interesting element is that the loop is very clean, the same functions as a displacer cylinder AT top, and MOTOR cylinder at BOTTOM.
Dead space is not very low.
The mechanism is not very complex and consists of four gears with a single axis motor output.
As for all other elements it is clear that regard the "passages" on the gas cycle, both through pipes, than the mesh / sponge net of the regenerator (referring the commercial devices adopted, diameter of wire, gauze, etc); the regenerator, as you know, is the foundant element of the 1816 Stirling patent.
Please excuse me.

[Ferraccio]

Stirling_Engine_Design.jpg

In reading the design spreadsheet from SESUSA, it talks about the length of the regenerator, the diameter of the regenerator housing, the free-flow area of the regenerator, the diameter of the regenerator wire, the mesh number of the wire mesh, and the number of gauzes in the regenerator stack.

Can someone explain these based on the above image?

Thanks, Michael

The draft is quite clair, except the fact that texts are are a bit shifted up, consider it down.

The regenerator is the annular chamber outside (higher) around the cylinder.
Is that part, with dark hatch from side to side,
below there is another part that is similar, is the cooler.
The top tubes are tubes of expansion:
The cooler is down the regenerator, and (like that) may consists of a metal sponge, but while the regenerator is thermally insulated (to retain the heat when is crossed by the gas (hot) from top to down, and when it goes back (cool) from the gas cooler), the cooler instead must be cooled by contact with the outer wall, in this case probably by a water jacket.
The chiller can be also formed by the condensation tubes, crossed by the gas, cooled externally by cooling fluid (water?)

The part of the head has to be hot, the bottom (cooler and the rest of the machine) must be cold, have to be a diaphragm interposed in insulating material that prevents heat transfer by conduction to the cold metal; the heat that passes by conduction in the metal is a serious loss, which reduces the yield.
Mesh, wire, Gauzès, ... are metallic materials, which were chosen to constitute the bulk of the recuperator: the materials in fine wire or meta wooll with low mass, and very large surface area, enabling a faster accumulation of heat, rapid temperature rise when heated and the opposite when cooled.
As you know rapid flow, large surface and high difference of temperatures allow adequate change of calour, ...as requested.

With all modesty on my part, I think that if you make these questions you are not very knowledgeable of Stirling engines, no criticism, we have clarified for the parts interested in a very good (complex) engine, of medium-high level.
Please note that there are engines easier, ...or much easier, with different architectures, but also keep in mind that you can find anything, (after your question I found a low temp. Japanese engine "alpha" that produce 750 watts with weighs two tons (!), ... and I seriously doubt it will work), but also I can easily go wrong.

[Aviator168]

This is an interesting powerful stirling.

http://www.youtube.com/user/hdkivela2#p ... Ixl-2ZZVfs

[Ferraccio]

I think that there is no serious possibility to have a pressurized engine with outside crankshaft and flywhell.
You lose many power to keep pressure, or you need an external compressor, this solution however is available only with air as fluid.
The reference is instead interesting to note the difference in pressurizing.

I make reference to another discussion in our forums:
http://stirlingengineforum.com/viewtopic.php?f=1&t=774
in said discussion I report a beautiful image of a really hy-tech engine (for 1983), but however out of our possibility.
(We have to fly much lower....)
http://books.google.com/books?id=RN4_jL ... &q&f=false
(May be the very thin expansion tubes (gas is hydrogen) are in Hastelloy, or more expensive alloy).
The hot parts are orange, the cold light blue, in the middle the separation diaphragm (withe).
Is the engine four cylinders, four pistons double acting, alpha, yet proposed in scheme.
The machinery are by sliding blocks, connecting rods and gears.

[Ferraccio]

Whit my bad english I do not know if you have had answer about start of the engine.
If the engine (and generator) is close in a box, what can start the engine? Or an electric motor start-up, or rather the generator that functions as well as motor.

[Ferraccio]

Blair FOR YOUR SCHEME SEE:

http://books.google.com/books?id=RN4_jL ... &q&f=false

The four cylinders are 90° phased, and for so the gas pass correctly from the hot side of the piston, through regenerator (yellow), and cooler (violet), to the cold site water (blue) refrigerated of the following piston, and the cycle is continuated so in circle to the four cylinders.
halfway between the hot side (orange) and cold (violet purple) There is a diaphragm of an insulating material, PORCELAIN, I thought.
Every piston is motor (down part) and dislocator (upper part).

The engine is hydroger filled and pipes in this case are many, and are really very small.
The engine is dated '60, now exists lubrication systems with poor oil or without at all.

[Ferraccio]

Of course the flow goes back from cold, through the cooler and the regenerator to the hot site.

[joncro55]

Using basic principles of measuring wire mesh or wire cloth, such as opening size and wire diameter ( http://www.bwire.com/resources.html#how ... wire_cloth )

What size woud you sau would be best to use in this instance? Something very fine like a 50 x 50 mesh and thinner or wide wire diameter? Its just tough to pick a mesh without actually looking at them and holding them in your hand to see how flexible they might be.

[Ferraccio]

You've done a question of million dollars.
The project od a regenerator for Stirling is one of more diffucult in thermodynamic (not my words).

For air may be is net mesh in stainless steel in gauzes stacked (cross flow), wire of order of 1/100 of inch, mesh of order0f 1/30 of an inch.
The values have ​​to be taken only as an approx. guideline!! Each one has its own ideas.
For hydrogen or elium very smaller clearances, in order od 1/100 of inch or less, may be with metallic sponge, or porous thermally conductor porcelain .

[Ian S C]

Another material for regenerators is stainless steel foil, .0015" to .oo2" thick. Either mark it lengthwise with an old ball point pen, lines about 1/8" apart from alternate sides, or dimpled with a star wheel (I think it's called a tracing wheel), The foil should fill about 10% of the chamber area. This way of doing it is much simpler and tidier than the gauze, and a lot less work than wire that really needs to be wound in the form of a basket, so that it retains its shape.
If you must have an external flywheel, you could follow Andy Ross and try a magnetic drive, that he used on the E70 and B90 motors. Ian S C

[Ferraccio]

If possible is good Nickel alloy, as costantan, that may be is found in very thin foils; nickel alloy is better heat conductor.
Regenerator have to collect and yeld heat faster as possible. The speed of transfer is proportional to conductivity.

[Ferraccio]

Of course copper, silver, gold-platinum alloy, platinum, or iridium are the best, but some are not stable at high temperature (such as copper, or the silver), or have some other spiritual element that it discourages the use. e.g. a spiritual element may be is extract too much money from the pockets.

Nickel alloy are allowable as industrial material, in thin plates or wires.

[Ian S C]

Whispertech here in Christchurch NZ tried platinum in the form of catalytic converters with out much success. Gold and the like, apart from the ecconomics, is too good a conductor, the metal used should retain heat but not conduct along its length, its the old problem with hot air engines, keeping the hot end hot, and the cold end a bit less hot... I mean cool. Ian S C