Search found 102 matches
- Thu Apr 25, 2024 8:41 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Stirling-Apha heat pump, and finned pistons
- Replies: 6
- Views: 60
Re: Stirling-Apha heat pump, and finned pistons
I think you've already noticed, but the big issue with any alteration / increase of surface area is that it tends to also increase the dead volume, which is generally considered "a bad thing" but maybe its a worthwhile trade-off?
- Thu Apr 04, 2024 7:04 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: The TRUTH? η = 1 – (Qc / Qh) = 1 – (Tc / Th)
- Replies: 368
- Views: 14546
Re: The TRUTH? η = 1 – (Qc / Qh) = 1 – (Tc / Th)
Tom,
If you could build an engine that had ice at the cold end, but that ice never, ever melted, what role would it have within the engine?
My intuition says that if no heat/energy transfers into the ice, then it isn't having any effect on the engine cycle.
If you could build an engine that had ice at the cold end, but that ice never, ever melted, what role would it have within the engine?
My intuition says that if no heat/energy transfers into the ice, then it isn't having any effect on the engine cycle.
- Thu Mar 14, 2024 6:32 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Model LTD max power effort
- Replies: 106
- Views: 39574
Re: Model LTD max power effort
I guess it's all theoretical to a degree, but if going with kinetic theory then each gas atom or molecule is moving independently with a lot of space in between hardly interacting with each other at all. If that is true than the idea that some of the hot gas can exert "pressure" to the co...
- Fri Mar 01, 2024 4:49 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Accordion style heat input plates
- Replies: 53
- Views: 11482
- Fri Mar 01, 2024 4:33 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: New Heat Engine
- Replies: 3
- Views: 877
Re: New Heat Engine
The efficiency of this kind of engine is going to depend not just on the relative heat of hot versus cold reservoirs, but also on how much energy is required to pump your working fluid around. This is fundamentally the same as for a Hot-Air engine, except that water has much more mass than air does....
- Thu Feb 29, 2024 10:17 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Choosing bearings for Flywheel
- Replies: 7
- Views: 1188
Re: Choosing bearings for Flywheel
Not directly answering your question, but my advice would be to make the flywheel narrower and larger in diameter.
- Fri Feb 09, 2024 1:57 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Regenerator Material Selection
- Replies: 8
- Views: 1729
Re: Regenerator Material Selection
My own personal, but completely unproven theory is that a regenerator will improve the efficiency of some badly designed engines, but I just can't see how it could improve on a theoretically perfect engine, as it will rob pressure when it absorbs heat.
- Thu Feb 08, 2024 3:01 am
- Forum: Stirling and "Hot Air" Engine Forum
- Topic: Stirling phone charger
- Replies: 35
- Views: 6123
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: 1729
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: 3006
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: 164583
- 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: 2184
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: 6123
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: 138478
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: 20881
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...