Stirlingengineforum.com

"This has compressed the air and heated it. Then an atomized water spray is injected. This combination causes the mist to evaporate and expand." I don't think so - but I'd welcome any new understanding. You can't steam water by injecting it into compression-heated air, because the pressure...

Layman's terms is all I got, and I don't know any definitive equations. For what it's worth, this is what I did: Make a series of simple two-dimensional drawings of a 90 degree "V" twin - it relates to any other 90 degree phased arrangement. Put pistons in their relative positions in the c...

Vamoose, I think understanding Alpha compression ratios is the problem. After a bit of playing on graph paper, it looks like a 90 degree phased twin with the same displacement cylinders and moderate length rods (to minimize deflection) will have about a 5-1 compression ratio - accounting for absolut...

Vamoose, the extent of my research on radiation and water is to note that it heats up in a microwave, and is kept hot in mirrored vacuum bottles. Somewhere between or around its obvious limitations it might have a use. I only mentioned it since you're leaving no stone unturned. For now, I've decided...

I've wondered about displacers and radiation that way, but only so far as black paint, which just becomes another insulation tradeoff problem. The anodizing is interesting. I've heard of the notion of using water in air, not for phase-change, but to make a mist and increase conduction. Don't know ho...

Well gosh, Geoff, since you ask; one way to increase internal surface area is a big-bore short-stroke design. My power diaphragm is 15'' stroking 1". It's a Beta directly over a 12'' dia. displacer chamber - which I wish I'd made bigger for a shorter displacer stroke and to lower the compressio...

"I don't want to assist the process with added heat (from light or other source) just air temperature on top as heat source and the cooling by evaporation on bottom. Otherwise this would defeat the purpose: i.e. to see if evaporative cooling alone would work." Tom, it seems like it might e...

Just my two cents on pressurization if you haven't settled on a design yet. What matters is not how much air that can be moved, but how much heat that can be moved. Pressurized air can obviously move more heat, but as the pressure goes up, the exchanger area per equal unit of air or heat is compromi...

I've seen anecdotes that JB weld is a fairly good thermal conductor. No definitive numbers though. The standard formula is rated for 500 F. (260 C.) I used it successfully on broken motorcycle cooling fins and side covers, even built up a portion and drilled and tapped it. I didn't torque that bolt ...

Vamoose, all I've ever made run yet is a little toy, so know this is just my theory. The sizing and whatever dead space you come up with determines the compression ratio. I read somewhere that the compression ratio should only be about half of the heating ratio. That makes sense to me since there ne...

Congratulations derwood - it takes commitment to get a bigger engine going. Mine keeps getting covered with layers of other shop projects and dust. Could you be more specific about getting the volume ratio "close" as in what is the overall compression or expansion ratio? Operating temp rat...

It's funny, the things that keep you up all night. Some 9" pie plates and silicone rubber cooking pans are still on the counter where I was fooling with this very thing. Except I was thinking just one metal plate on the displacer hot side, with the matrix material between it and the perforated ...

Geoff, I don't think a phase shift is needed to make a thermal lag engine run. I believe the original patent only relied on the natural slowing of the piston resulting in longer duration at either end of its travel, raising or lowering the average temperature for the following stroke. It's a very mi...

by Geoff V » Fri Apr 20, 2012 9:36 am "but they seem lost amonst the hundreds of Hot Air engines, Tin can engines and Thermo Lag engines (often mistakenly refered to as Laminar flow engines) though the last thing you'll find in one is laminar flow." Geoff, In the thermal lag engines that h...

Thanks Junkie. Did you use anything between the balloon and the rtv? I would have thought they would bond tighter than that. Neat video, though it's been a half-hour and I can't get past 0:47. I almost never watch videos because I'm on dial-up and usually get more out of diagrams anyway, but I alway...