Search found 110 matches
- Thu Feb 08, 2024 3:01 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Stirling phone charger
- Replies: 35
- Views: 10451
Re: Stirling phone charger
I'm sure it's worth looking at one of those, but from what I've seen in the past, they are _too_ highly geared - intended for a crank speed at least one-tenth of what an engine would run at, but maybe that can be overcome with different gearing?
- Thu Feb 08, 2024 2:56 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Regenerator Material Selection
- Replies: 8
- Views: 3989
Re: Regenerator Material Selection
I'm trying to build a LTD gamma configuration Stirling engine. From my research I've seen the two most popular material selections have been aquarium filter foam and a metal foam. Do you guys have an suggestions of other materials to make this engine more efficient? Your title mentions "Regene...
- Wed Feb 07, 2024 4:04 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Atmospheric pressure ?
- Replies: 33
- Views: 7083
Re: Atmospheric pressure ?
Tom, What I see a few posts up, is a quote about a process seen in Botany , where sap gets lifted up trees beyond what 'positive pressure' can explain. I can't pretend to provide a full explanation of how capillary action works, but I do know that it has at least something to do with "surface t...
- Thu Jan 11, 2024 9:24 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: "Thermoacoustic" Stirling - theory of operation
- Replies: 129
- Views: 171934
- Wed Jan 10, 2024 1:38 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: High Efficiency Power Generation for Hot Air Engines
- Replies: 9
- Views: 4153
Re: High Efficiency Power Generation for Hot Air Engines
Sounds like you need to measure the actual power draw of the Dremel, since you seem to be getting over 24watts out from only 8watts in ...
- Fri Jan 05, 2024 1:37 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Stirling phone charger
- Replies: 35
- Views: 10451
Re: Stirling phone charger
As ever, watch out for quality with car chargers - converting 12v to 5v leaves plenty of head-room for really crap circuitry that might rob all your power at lower voltages. If you are going down that route (sounds like you aren't) then I would be looking at the kind of "buck-boost convertor&qu...
- Fri Nov 03, 2023 9:17 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: I'm planning to build a Stirling generator to work off heat from our kitchen stove.
- Replies: 88
- Views: 140467
Re: I'm planning to build a Stirling generator to work off heat from our kitchen stove.
I read that pressurizing the cylinders adds efficiency, but I don't know how feasible it is with a diaphragm. I don't think it makes much difference whether you use a diaphragm or a traditional piston - pressurisation is a problem for both, as it is primarily the external/atmospheric pressure that ...
- Thu Oct 12, 2023 4:19 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Rarefication
- Replies: 33
- Views: 21282
Re: Rarefication
what type of engine are you talking about that is easy/simple compared with Stirling/hot air? What I meant was that with IC engines you can quite confidently state that during the combustion stage, the only relevant processes are expansion and heating. In a steam engine or a jet turbine the various...
- Tue Oct 10, 2023 2:29 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Rarefication
- Replies: 33
- Views: 21282
Re: Rarefication
... there could be more than one factor in play Ah, but that's the thing, isn't it? Some other types of engine it might be easy/relevant to use a simple model, but for Stirling/Hot-air engines there is ALWAYS more factors at play, the difficulty is in working out which ones have a significant effec...
- Mon Oct 09, 2023 4:59 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Rarefication
- Replies: 33
- Views: 21282
Re: Rarefication
Tom, I don't think you need to be a believer in Kinetic Theory, or any other specific theory, to see that ultimately, the component molecules of your working fluid push on the power piston individually, though it is always easier to think of them "as a whole". All things being equal (which...
- Fri Oct 06, 2023 8:19 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: The Carnot efficiency problem
- Replies: 258
- Views: 119537
Re: The Carnot efficiency problem
The corollary to that point, is that the hot end will tend to be self-regulating (though maybe not always sufficiently!) - heat transfers faster (apparently) between items that have a large temp difference than a small difference, so if the working fluid starts to heat up, presumably the rate of tra...
- Fri Oct 06, 2023 8:08 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Rarefication
- Replies: 33
- Views: 21282
Re: Rarefication
Les, The trouble with that description of Adiabatic processes, is twofold: 1. In the real world, and especially in hot-air engines, there is ALWAYS some heat transfer in/out of the walls of the engine. 2. Timing. At low speed, or in step-by-step analysis, all of the working-fluid changes temp/pressu...
- Fri Sep 08, 2023 5:04 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Making Glass and Ceramic Stirling engines
- Replies: 47
- Views: 26303
Re: Making Glass and Ceramic Stirling engines
If the clay won't settle, I guess you'll just have to dry it like salt?
- Thu Aug 31, 2023 8:28 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Constant volume compression/expansion-displacer chamber analysis-heat powered mechanical amplifier
- Replies: 50
- Views: 29522
Re: Constant volume compression/expansion-displacer chamber analysis-heat powered mechanical amplifier
Tom/Vincent, Interesting thoughts. As ever, the real world proves more complex than any 'model/theory' however one thing to bear in mind here is that there are generally considered to be two entirely separate methods of heat transfer: Conduction (which seems to be what you are talking about above) b...
- Thu Aug 31, 2023 4:40 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: The Carnot efficiency problem
- Replies: 258
- Views: 119537
Re: The Carnot efficiency problem
Helium for example can hardly be liquified by any extreme of external cooling and pressure, yet it can be liquified by this method of having it do work expanding in a cylinder to drive an engine to do external "work". Was that a typo? If the expansion of the gas cools it down far enough t...