I was just looking through the reseller websites for the Vulcan Stove Fan, and...
- Resize_20240128_053913_3466.jpg (67.09 KiB) Viewed 4577 times
A mixture of shock, dismay, and...could I afford to buy it? Sadly, no. don't think so...
Stirling.engine NEWS
Stirling.engine NEWS
This is an interesting development, I think.
I was just looking through the reseller websites for the Vulcan Stove Fan, and...
https://www.stirlingengine.com/product/ ... stove-fan/
A mixture of shock, dismay, and...could I afford to buy it? Sadly, no. don't think so...
I was just looking through the reseller websites for the Vulcan Stove Fan, and...
https://www.stirlingengine.com/product/ ... stove-fan/
A mixture of shock, dismay, and...could I afford to buy it? Sadly, no. don't think so...
New? displacer concept revealed
https://www.stirlingworks.co.uk/innovation
The use of a kind of spiral planar spring as a displacer is quite interesting.
https://youtu.be/knhXOnILotk?si=k-neaYUVwnu5OXOL
I was excited to see the initial description at the early part of the video, as it appeared to be a method of effectively dispensing with the cold "sink" side of the engine.
The final "two displacer" design, one hot and the other cold, though, was, for me anyway, a bit of a let down.
The hot AND cold together, as animated:
Aside from the planar spring innovation, I had come up with a similar design way back in 2006 which I had posted a link to here to the forum at that time.
https://members.tripod.com/prc_projects/stirling.html
The phone # and address on that page are no longer valid, but the email is.
viewtopic.php?f=1&t=77&p=150#p156
Anyway, as I started saying above, the hot AND cold displacers together, as animated, do nothing, as far as I can see, to eliminate "mixing" or intermingling of hot and cold air. The surface area is increased tremendously, but as shown by my 2006 design, there are other ways of accomplishing that.
What I THOUGHT was fantastic about this new planar spring style displacer innovation, as I first imagined it or as first demonstrated in Andrew Hall's video is, or was...
This "coil" or planar spring displacer design used as a kind of HEAT VALVE, with no open spaces between the spirals and no upright fins protruding up through the spaces, could be very effective as an INSULATOR to cover the hot side and prevent heat addition to the working fluid.
Then lifting the spiral would open up numerous passageways, fully exposing the hot plate. Then it could be lowered to again, cleanly cut off heat input. With dwell, the bottom part of the displacer/heat valve could take up heat during the down, dwell period, and provide additional surface area for exchanging heat with the working fluid when raised.
The concave shape would help to eliminate some dead air space, which would be advantageous I think.
Anyway, the exciting news of a new radical ino action, for me, turned into a kind of ho hum, same old same old Carnot fallacy infected concept of removing heat after adding it, dumping the "waste heat" to a cold side, but now a cold side with enormous (unnecessary IMO) surface area designed to eliminate an abundance of "waste heat" that is not actually there, if it was CONVERTED to WORK output as heat engines are supposed to do.
A curved bottom hot plate is hardly necessary IMO, so what I would do with this basic planar spring displacer concept would be something like this:
As, hopefully, can be seen, the planar spring/spiral "displacer"/heat valve (illustrated in blue) has tight fitting spirals with absolutely minimal air gap, just enough to provide clearance and avoid binding and friction.
If there are prongs or a spiral vane or grove of some sort to increase surface area for heat exchange, this, IMO, only provides benefit for heat INPUT on the hot side
Once the working fluid is heated and expands transferring energy to the piston as WORK output, it naturally drops in temperature, due to the expenditure of energy.
The spiral displacer should be insulating on top and retain heat on the bottom.
The spiral "heat valve" should only "open" or lift, briefly when the piston is down (at "TDC"). To let in a quantity of heat the engine can utilize for each cycle and no more.
I've found that the magnetic displacer design is an effective way to accomplish this and is self regulating.
If the engine slows, the magnet lifts the displacer higher and for a longer period, adding more heat. If the engine speeds up, the displacer is lifted less and more briefly.
The use of a kind of spiral planar spring as a displacer is quite interesting.
https://youtu.be/knhXOnILotk?si=k-neaYUVwnu5OXOL
I was excited to see the initial description at the early part of the video, as it appeared to be a method of effectively dispensing with the cold "sink" side of the engine.
The final "two displacer" design, one hot and the other cold, though, was, for me anyway, a bit of a let down.
The hot AND cold together, as animated:
- Stirling-Engine-annimation-V7-ezgif.com-optimize.gif (222.7 KiB) Viewed 3875 times
Aside from the planar spring innovation, I had come up with a similar design way back in 2006 which I had posted a link to here to the forum at that time.
- stirling.gif (15.7 KiB) Viewed 3875 times
- regenerator_detail.gif (22.54 KiB) Viewed 3875 times
The phone # and address on that page are no longer valid, but the email is.
viewtopic.php?f=1&t=77&p=150#p156
Anyway, as I started saying above, the hot AND cold displacers together, as animated, do nothing, as far as I can see, to eliminate "mixing" or intermingling of hot and cold air. The surface area is increased tremendously, but as shown by my 2006 design, there are other ways of accomplishing that.
What I THOUGHT was fantastic about this new planar spring style displacer innovation, as I first imagined it or as first demonstrated in Andrew Hall's video is, or was...
This "coil" or planar spring displacer design used as a kind of HEAT VALVE, with no open spaces between the spirals and no upright fins protruding up through the spaces, could be very effective as an INSULATOR to cover the hot side and prevent heat addition to the working fluid.
Then lifting the spiral would open up numerous passageways, fully exposing the hot plate. Then it could be lowered to again, cleanly cut off heat input. With dwell, the bottom part of the displacer/heat valve could take up heat during the down, dwell period, and provide additional surface area for exchanging heat with the working fluid when raised.
The concave shape would help to eliminate some dead air space, which would be advantageous I think.
Anyway, the exciting news of a new radical ino action, for me, turned into a kind of ho hum, same old same old Carnot fallacy infected concept of removing heat after adding it, dumping the "waste heat" to a cold side, but now a cold side with enormous (unnecessary IMO) surface area designed to eliminate an abundance of "waste heat" that is not actually there, if it was CONVERTED to WORK output as heat engines are supposed to do.
A curved bottom hot plate is hardly necessary IMO, so what I would do with this basic planar spring displacer concept would be something like this:
- Resize_20240209_030108_8733.jpg (145.72 KiB) Viewed 3874 times
As, hopefully, can be seen, the planar spring/spiral "displacer"/heat valve (illustrated in blue) has tight fitting spirals with absolutely minimal air gap, just enough to provide clearance and avoid binding and friction.
If there are prongs or a spiral vane or grove of some sort to increase surface area for heat exchange, this, IMO, only provides benefit for heat INPUT on the hot side
Once the working fluid is heated and expands transferring energy to the piston as WORK output, it naturally drops in temperature, due to the expenditure of energy.
The spiral displacer should be insulating on top and retain heat on the bottom.
The spiral "heat valve" should only "open" or lift, briefly when the piston is down (at "TDC"). To let in a quantity of heat the engine can utilize for each cycle and no more.
I've found that the magnetic displacer design is an effective way to accomplish this and is self regulating.
If the engine slows, the magnet lifts the displacer higher and for a longer period, adding more heat. If the engine speeds up, the displacer is lifted less and more briefly.
Re: Stirling.engine NEWS
In an above paragraph appears:
"Ino action" it's probably not too difficult to figure out should read innovation, but, the silly auto correct turned a typo into something silly and completely meaningless, but, I ran out of time for edits. So, just for clarity, this additional addendum.Anyway, the exciting news of a new radical ino action,
Re: Stirling.engine NEWS
Having a flat bottom hot plate would not take advantage of the self oscillating spring action, which theoretically could increase efficiency.
However, synchronization with the power piston might be an issue. An advantage I think though would be that the spring displacer would return sharply to cover the hot plate and discontinue heat input.
It is, or was at one time fairly well known and understood that in steam engines, the greatest efficiency is achieved by allowing the cylinder steam intake valve to only open briefly and cut off the input by closing the valve early so that the working fluid could continue to expand adiabatically, taking full advantage of the heat and making condensing the steam much easier since it would cool down much more before exiting the cylinder.
Such considerations appear in Carnot's theories. The "Carnot cycle" was not Carnot's invention, it was simply known engineering.
Anyway, to mimic this adiabatic expansion of steam process in a hot air engine would require some means of cleanly cutting off the heat input allowing the hot air to expand and cool sufficiently to make the subsequent compression process possible without wasting heat.
But, perhaps a concave bottom that allowed the spring displacer to oscillate freely could be an advantage at high RPM where incorporating a "dwell" would be all but impossible anyway.
https://en.m.wikipedia.org/wiki/Cutoff_(steam_engine)
However, synchronization with the power piston might be an issue. An advantage I think though would be that the spring displacer would return sharply to cover the hot plate and discontinue heat input.
It is, or was at one time fairly well known and understood that in steam engines, the greatest efficiency is achieved by allowing the cylinder steam intake valve to only open briefly and cut off the input by closing the valve early so that the working fluid could continue to expand adiabatically, taking full advantage of the heat and making condensing the steam much easier since it would cool down much more before exiting the cylinder.
Such considerations appear in Carnot's theories. The "Carnot cycle" was not Carnot's invention, it was simply known engineering.
Anyway, to mimic this adiabatic expansion of steam process in a hot air engine would require some means of cleanly cutting off the heat input allowing the hot air to expand and cool sufficiently to make the subsequent compression process possible without wasting heat.
But, perhaps a concave bottom that allowed the spring displacer to oscillate freely could be an advantage at high RPM where incorporating a "dwell" would be all but impossible anyway.
https://en.m.wikipedia.org/wiki/Cutoff_(steam_engine)