I agree there must be dilution of the pulse in one direction or the other. It would be the same for Alpha and Beta, but Gamma is easier to see. But remember energy given up to the regenerator is supposed to be given back on the next blow.
Where to place the transfer port in a Gamma displacer chamber was a forum topic some years back, but I can’t remember enough specifics to search it out. Far as I can see there’s a loss no matter what. Just as well put it at the cool end to keep the power piston cool.
Bumpkin
3KW Stirling Engine - Pics provided
Re: 3KW Stirling Engine - Pics provided
I've now, more or less abandoned all prior vestiges of past heat engine theory where alternating hot and cold, or hot and cold "reservoirs" or whatever are necessary in favor of a "pure" kinetic theory of heat. I.e. so-called "heat" is transfer of kinetic energy. Nothing to compel a "flow" from hot to cold. True, the generally disordered random collisions result in a gradual "spreading out" of energy but that "spreading out" is not assisted or facilitated by the presence of "cold"
The gas particles, in other words, should have a clear unfettered path between heat source where kinetic energy transfers into the engine and piston, where kinetic energy transfers out of the engine.
In a reciprocating engine this necessitates a "pulsed" heat input, to drive the piston, alternating with periods of no heat input so as to allow the return of the piston between pulses.
My theory is then, that a heat "sink" imparts no benefit, only an obstacle or side path that has the effect of bleeding off supposed "excess" kinetic energy or "waste heat".
In other words, there is no intrinsic "waste heat" only mismanaged or miss directed kinetic energy.
As a "proof of concept" of sorts, consider this situation.
A mostly thermally insulated vacuum chamber containing one gas atom. There is one or two relatively small membranes where "heat" transfer may take place.
When the particle collides with a membrane, heat (kinetic energy) is imparted to it. It then bounces around unfettered until it happens to collide with a microscopic paddle wheel equipped with a ratchet that allows movement in one direction only.
On average there should be a tendency for the paddle wheel to turn and lift the attached external weight.
In other words, the particle picks up "heat" ( kinetic energy ) at a membrane, then in time imparts that energy to the ratchet.
Now a lot can go wrong. Maybe the gas molecule hits the ratchet twice, loosing all it's energy and stops, or possibly it collides with the membrane in such a way as loose all it's energy, leaving it to float aimlessly about inside the chamber.
Introducing a second molecule should compensate for such occurrences. Possibly a third, and a fourth etc.
Statistically there should still be a more or less direct transfer of energy from the heat input "membrane" to the ratchet, to effect external work output.
The point here is that there is only one "reservoir"
What would introducing a "cold" "sink" accomplish?
This would actually be just a LESS HOT membrane that would tend to absorb kinetic energy from the gas mecules in the chamber without giving any back.
The paddle wheel itself is the target "sink". (Absorber of kinetic energy) Having an additional low energy sink just reduces efficiency.
Practically speaking however, where heat sensitive magnets are in use, a cooling jacket is necessary to avoid damage to the magnets, but that speaks to poor design. The magnets could be positioned out of harms way.
Would a regenerator added into the picture be if any benefit in this paddle wheel arangement, vacuum chamber setup?
I don't see any benefit to introducing a regenerator into the picture.
I don't think that a "scaled up" version of the above box engine is necessary. I think a Stirling engine, generally, is already a scaled up version in principle, but this has not been generally recognized.
The gas particles, in other words, should have a clear unfettered path between heat source where kinetic energy transfers into the engine and piston, where kinetic energy transfers out of the engine.
In a reciprocating engine this necessitates a "pulsed" heat input, to drive the piston, alternating with periods of no heat input so as to allow the return of the piston between pulses.
My theory is then, that a heat "sink" imparts no benefit, only an obstacle or side path that has the effect of bleeding off supposed "excess" kinetic energy or "waste heat".
In other words, there is no intrinsic "waste heat" only mismanaged or miss directed kinetic energy.
As a "proof of concept" of sorts, consider this situation.
- Resize_20220927_132422_2235.jpg (179.17 KiB) Viewed 13994 times
When the particle collides with a membrane, heat (kinetic energy) is imparted to it. It then bounces around unfettered until it happens to collide with a microscopic paddle wheel equipped with a ratchet that allows movement in one direction only.
On average there should be a tendency for the paddle wheel to turn and lift the attached external weight.
In other words, the particle picks up "heat" ( kinetic energy ) at a membrane, then in time imparts that energy to the ratchet.
Now a lot can go wrong. Maybe the gas molecule hits the ratchet twice, loosing all it's energy and stops, or possibly it collides with the membrane in such a way as loose all it's energy, leaving it to float aimlessly about inside the chamber.
Introducing a second molecule should compensate for such occurrences. Possibly a third, and a fourth etc.
Statistically there should still be a more or less direct transfer of energy from the heat input "membrane" to the ratchet, to effect external work output.
The point here is that there is only one "reservoir"
What would introducing a "cold" "sink" accomplish?
This would actually be just a LESS HOT membrane that would tend to absorb kinetic energy from the gas mecules in the chamber without giving any back.
The paddle wheel itself is the target "sink". (Absorber of kinetic energy) Having an additional low energy sink just reduces efficiency.
Practically speaking however, where heat sensitive magnets are in use, a cooling jacket is necessary to avoid damage to the magnets, but that speaks to poor design. The magnets could be positioned out of harms way.
Would a regenerator added into the picture be if any benefit in this paddle wheel arangement, vacuum chamber setup?
I don't see any benefit to introducing a regenerator into the picture.
I don't think that a "scaled up" version of the above box engine is necessary. I think a Stirling engine, generally, is already a scaled up version in principle, but this has not been generally recognized.
Re: 3KW Stirling Engine - Pics provided
Not the same principle but there was the Crookes radiometer: Well shoot I can’t stick the link so you’ll have to look it up.
Bumpkin
Bumpkin
Re: 3KW Stirling Engine - Pics provided
There actually may be some parallels.
In particular, there is a certain ideal level of vacuum in the radiometer at which it runs most efficiently.
That is similar in principle with the observations in the "rarefaction" discussion:
viewtopic.php?t=2700
The density of the gas, "mean free path" or how far the gas molecule can travel before a collision.
Too few or too many molecules and the effect is nullified.
Generally it would be said that the engine has come up to "operating temperature" when the ideal balance has been reached.
Other than that general parallel, the mechanics of a Stirling engine are quite different.
In particular, there is a certain ideal level of vacuum in the radiometer at which it runs most efficiently.
That is similar in principle with the observations in the "rarefaction" discussion:
viewtopic.php?t=2700
The density of the gas, "mean free path" or how far the gas molecule can travel before a collision.
Too few or too many molecules and the effect is nullified.
Generally it would be said that the engine has come up to "operating temperature" when the ideal balance has been reached.
Other than that general parallel, the mechanics of a Stirling engine are quite different.
Re: 3KW Stirling Engine - Pics provided
I was finally able to get my FULL helium tank back this morning. Only took about six weeks. I thought, given the "shortage" it would be horrifically expensive, but it actually wasn't too bad. Just $40. I was shocked.
- Resize_20221021_154829_9035.jpg (238.58 KiB) Viewed 13752 times
Re: 3KW Stirling Engine - Pics provided
Hi
Did you manage the filling up ?
Did you manage the filling up ?
Re: 3KW Stirling Engine - Pics provided
Not with helium as yet. When I had the time, helium was not available.
I did pressurize it to verify that it could at least hold air. The wires through the casing appeared a bit frayed, but it seems OK.
A bit strangely, while filling it started to hum as if it were running for maybe 10 or 20 seconds.
I assume this was from the gas passing around the piston causing it to vibrate as the pressure equalized.
Re: 3KW Stirling Engine - Pics provided
It's been fully pressurized with helium:
https://youtu.be/9EaSgmoQkd4?si=LSzHaHhA5rekMKpK
And today I finished putting together a makeshift cooling system.
https://youtu.be/upO-S9hylCo?si=3rQs4ljBtDFHqgZH
In reviewing some specs on this thing, such as are available, to get 3000 watts from this engine, the design parameters would dictate it would require about 10,000 watts of heat input, 7,000 of which would be "rejected" to the cooling system.
Now, this engine is supposed to be able to "self start" soon after sunrise with a 15 foot diameter parabolic dish supplying the concentrated solar as a heat source.
Is there another way to supply 10,000 watts of heat to an area about the size of a small frying pan ?
If I could tip it up vertical over one of these kind of propane cookers, I'm pretty sure that would do the trick
The kerosene blast heater had plenty of BTU's, in theory, but that was a high volume air flow heater. The heat was too diluted by the high volume of air.
Propane does not produce as much heat in BTU's, supposedly, but I think the direct heat from a propane cooker should heat up the engine better than the hot air from the kerosene heater.
I've checked all the local stores, though, and haven't been able to find one locally, otherwise I might have had the thing running by now.
Another potential issue might be vibration, If I do get it running. As it is it is mounted on this frame with these flexure springs, but vertical on top of a cooker it's liable to start bouncing around without anything to absorb the vibration. I may have to rig up some kind of shock absorbers or springs or suspend it from the ceiling or something.
Also still have to wire up the possible output to a rectifier and some electrical load.
https://youtu.be/9EaSgmoQkd4?si=LSzHaHhA5rekMKpK
And today I finished putting together a makeshift cooling system.
https://youtu.be/upO-S9hylCo?si=3rQs4ljBtDFHqgZH
In reviewing some specs on this thing, such as are available, to get 3000 watts from this engine, the design parameters would dictate it would require about 10,000 watts of heat input, 7,000 of which would be "rejected" to the cooling system.
Now, this engine is supposed to be able to "self start" soon after sunrise with a 15 foot diameter parabolic dish supplying the concentrated solar as a heat source.
Is there another way to supply 10,000 watts of heat to an area about the size of a small frying pan ?
If I could tip it up vertical over one of these kind of propane cookers, I'm pretty sure that would do the trick
- Resize_20240215_014259_9210.jpg (91.86 KiB) Viewed 5353 times
The kerosene blast heater had plenty of BTU's, in theory, but that was a high volume air flow heater. The heat was too diluted by the high volume of air.
Propane does not produce as much heat in BTU's, supposedly, but I think the direct heat from a propane cooker should heat up the engine better than the hot air from the kerosene heater.
I've checked all the local stores, though, and haven't been able to find one locally, otherwise I might have had the thing running by now.
Another potential issue might be vibration, If I do get it running. As it is it is mounted on this frame with these flexure springs, but vertical on top of a cooker it's liable to start bouncing around without anything to absorb the vibration. I may have to rig up some kind of shock absorbers or springs or suspend it from the ceiling or something.
Also still have to wire up the possible output to a rectifier and some electrical load.
Re: 3KW Stirling Engine - Pics provided
This is a cropped image of an animation from an old INFINIA website I retrieved from the internet archive ("Wayback machine") showing the proximity of the heater head to the water circulating cooling system.
The pipe sticking out on top is the cold water inlet pipe.
I cannot say the animation is 100% accurate but from my own first hand examination of the actual engine it seems close.
Further, when I applied a red hot 1000 watt hot plate directly to the heater head focal point, trying to heat up the "hot end" of this engine was rather like trying to boil a 5 gallon bucket of water with a candle. Reading the attached thermocouple nearest to the heater head the progress of increase in temperature was extraordinarily slow.
I would, of course, have to dismantle the engine, or given that the hot end and cooling jacket area are welded together, cut the thing in half to get a good view, I have no reason to doubt the basic accuracy of the animation.
Further, I've also seen other actual cut away views and dismantling of similar "NASA" engines of nearly the same construction and the issue of the extremely close proximity of the cooling jacket to the heater head appears to be compounded by the water jacket area being made of copper to maximize heat transfer to the cooling water
So it looks like the heater head and cooling chanel are not only close or inches apart, but internally, actually sandwiched together, right up against each other.
Now I can see how such an arrangement, given an extremely high heat input, could result in a sharp division between the hot plate and the cold water jacket, with very little displacer motion being necessary, but, REALLY?
This seems hardly an engine at all. It seems more like just a hot water heater.
Now hopefully I'm wrong and the heater head is constructed from some space age alloy that conducts very little heat, but, in my efforts so far, from what I've been able to tell, the heat I've been applying is virtually all going straight into the cooling water. Thus the necessity for the water circulating pump and large cooling fan, to keep the water from boiling before the engine can even get started.
OK, so, as this thing is getting up to temperature, as the sun is rising, It is already getting so hot it needs to have the water pump and fan running to keep it cool before it's even hot enough to get started!
So far, my experience has been in exact accord with these statements.
Before I added the pump and fan I thought I might be able to run the engine using convection alone to keep the water circulating.
But,... I only got, perhaps as far a boiling some water. In order to get this thing running the heat input needs to be extreme enough so as to overcome the rapid heat loss to the cooling system, adding heat faster than it can be thrown away.
And coming up with this brilliant design only took about $200,000,000.00 taxpayer dollars, over the course of a few decades, with a good 200 years of supposedly "proven" thermodynamic theory behind it. ie:To run a heat engine you need to TRANSPORT the heat to the cooling water as quickly and efficiently as possible.
What better way to do that than to bypass the working fluid altogether and send the heat straight to the cooling water?
Sounds like a plan
- ezgif.com-optimize (2).gif (234.91 KiB) Viewed 5346 times
The pipe sticking out on top is the cold water inlet pipe.
I cannot say the animation is 100% accurate but from my own first hand examination of the actual engine it seems close.
Further, when I applied a red hot 1000 watt hot plate directly to the heater head focal point, trying to heat up the "hot end" of this engine was rather like trying to boil a 5 gallon bucket of water with a candle. Reading the attached thermocouple nearest to the heater head the progress of increase in temperature was extraordinarily slow.
I would, of course, have to dismantle the engine, or given that the hot end and cooling jacket area are welded together, cut the thing in half to get a good view, I have no reason to doubt the basic accuracy of the animation.
Further, I've also seen other actual cut away views and dismantling of similar "NASA" engines of nearly the same construction and the issue of the extremely close proximity of the cooling jacket to the heater head appears to be compounded by the water jacket area being made of copper to maximize heat transfer to the cooling water
So it looks like the heater head and cooling chanel are not only close or inches apart, but internally, actually sandwiched together, right up against each other.
Now I can see how such an arrangement, given an extremely high heat input, could result in a sharp division between the hot plate and the cold water jacket, with very little displacer motion being necessary, but, REALLY?
This seems hardly an engine at all. It seems more like just a hot water heater.
Now hopefully I'm wrong and the heater head is constructed from some space age alloy that conducts very little heat, but, in my efforts so far, from what I've been able to tell, the heat I've been applying is virtually all going straight into the cooling water. Thus the necessity for the water circulating pump and large cooling fan, to keep the water from boiling before the engine can even get started.
Source: https://www.machinedesign.com/markets/e ... nditioningSunlight gets concentrated in an 800-to-1 ratio, which would raise the temperature at the heat-resistant nickel-alloy concentrator to 2,000°C if the Stirling generator didn’t extract heat from it and keep it at about 650°C, says Tim Talda ...
....The PowerDish uses an electric pump and fan-cooled radiator to circulate about a gallon of a 50/50 water/glycol mix around the Stirling generator’s cool side. The pump and fan are the most-significant sources of noise for the device, which creates about 65 dBA at 33 ft from the dish. Power to run the pump and fan usually comes from the PowerDish, but if it is not yet making enough power, the PowerDish will pull the needed electricity from the grid.
OK, so, as this thing is getting up to temperature, as the sun is rising, It is already getting so hot it needs to have the water pump and fan running to keep it cool before it's even hot enough to get started!
So far, my experience has been in exact accord with these statements.
Before I added the pump and fan I thought I might be able to run the engine using convection alone to keep the water circulating.
But,... I only got, perhaps as far a boiling some water. In order to get this thing running the heat input needs to be extreme enough so as to overcome the rapid heat loss to the cooling system, adding heat faster than it can be thrown away.
And coming up with this brilliant design only took about $200,000,000.00 taxpayer dollars, over the course of a few decades, with a good 200 years of supposedly "proven" thermodynamic theory behind it. ie:To run a heat engine you need to TRANSPORT the heat to the cooling water as quickly and efficiently as possible.
What better way to do that than to bypass the working fluid altogether and send the heat straight to the cooling water?
Sounds like a plan
Re: 3KW Stirling Engine - Pics provided
The saving grace however, IMO, is that the Stirling engine is so inherently efficient that once actually started, the conversion of heat to power is so rapid and effective being largely due to adiabatic expansion, there remains scant "waste heat" left over that could be transfered to the cooling water.
It appears that the better than anticipated conversion caused problems for CHP applications. There simply was not enough "waste heat" from the engine to utilize for domestic heating and hot water.
At the Fort Carlson test site for example, while the Power Dish underperformed generally:
With a high cycle rate, the heat is converted to mechanical output so rapidly there simply is not enough time for heat loss or waste through conduction.
Of course, however, when you place the hot heat exchanger or heat input plate into direct contact with the cooling jacket through a copper heat exchanger, a great deal of loss through direct conduction is inevitable, but IMO the fact that such a poorly engineered design could operate and produce any useable output whatsoever is testament to the incredible inherent efficiency of these engines even under the worst possible circumstances.
Just think what might be accomplished if this guy were on the NASA engineering team
https://youtu.be/u-YfPEFBh70?si=Zb17FaO7NU_Cx9rL
He's supplying heat to the engine at both ends, heat from the wood stove on the hot side and near boiling water on the LESS HOT side.
Is this not, however, how ALL Stirling engines operate?
Water "cooling" can only go as low as 273° Kelvin. Ambient air cooling hotter than that.
It makes sense to me that a relatively hotter average temperature would produce more power in spite of a reduced ∆T even if that contradicts "established science".
One might ask however, when, where and by whom, using what experimental method was it ever conclusively established that the greater the ∆T the higher the efficiency ?
I've been trying to find an answer to that question since about 2010.
It appears that the better than anticipated conversion caused problems for CHP applications. There simply was not enough "waste heat" from the engine to utilize for domestic heating and hot water.
At the Fort Carlson test site for example, while the Power Dish underperformed generally:
Attempts to remedy the "problem" of too little "waste heat" being available by running the engine hotter resulted in heat damage to the systems sensitive linear alternator.In total, the PowerDish CHP provided 54% of the actual electricity and 6% of the actual thermal energy used by the Fort Carson facility....
...30% lower than the predicted output of 16,000 kWhth for thermal energy production at the Fort Carson site.
With a high cycle rate, the heat is converted to mechanical output so rapidly there simply is not enough time for heat loss or waste through conduction.
Of course, however, when you place the hot heat exchanger or heat input plate into direct contact with the cooling jacket through a copper heat exchanger, a great deal of loss through direct conduction is inevitable, but IMO the fact that such a poorly engineered design could operate and produce any useable output whatsoever is testament to the incredible inherent efficiency of these engines even under the worst possible circumstances.
Just think what might be accomplished if this guy were on the NASA engineering team
https://youtu.be/u-YfPEFBh70?si=Zb17FaO7NU_Cx9rL
He's supplying heat to the engine at both ends, heat from the wood stove on the hot side and near boiling water on the LESS HOT side.
Is this not, however, how ALL Stirling engines operate?
Water "cooling" can only go as low as 273° Kelvin. Ambient air cooling hotter than that.
It makes sense to me that a relatively hotter average temperature would produce more power in spite of a reduced ∆T even if that contradicts "established science".
One might ask however, when, where and by whom, using what experimental method was it ever conclusively established that the greater the ∆T the higher the efficiency ?
I've been trying to find an answer to that question since about 2010.