h a l f b a k e r y
Why did I think of that?
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At first glance, this device resembles an internal
combustion engine -- it has cylinders, pistons, a
crankshaft and connecting rods, cylinder heads, poppet
valves, and intake and exhaust manifolds.
At second glance, one notices that there are four
manifolds: An interior intake manifold, an
exhaust manifold, an exterior intake manifold, and an
exterior exhaust manifold. Naturally, each cylinder
head has four separately controlled valves or sets of
valves, instead of the usual two of an ICE.
The interior of each of the engine's pistons has a block
of water adsorbing material attached to it -- probably a
block of silica gel beads.
Each piston moves up and down through a six stroke
At the beginning of the first stroke, the piston is at
TDC, and all valves are closed. The interior intake
valve opens, and the piston moves downward, causing
air from the room being dehumidified to move in to the
At the beginning of the second stroke, the piston is at
BDC, and the intake valve closes. As the piston moves
up, the air is compressed. As air is compressed, latent
heat (humidity) is forced into the adsorbent, and
sensible heat is conducted into the piston, cylinder
walls, and cylinder head.
During the third stroke, the piston moves partway down
with all valves still closed. Because both heat and mass
have been transferred out of the air, it reach will
atmospheric pressure *before* BDC. When this
happens, the interior exhaust valve opens. The piston
then continues to BDC.
For the fourth stroke, the piston rises with the interior
exhaust valve open, sending the cooled, dehumidified
air back into the room from which it came.
At the beginning of the fifth stroke, the interior exhaust
valve closes, and the exterior intake valve opens.
The piston descends partway, allowing some air from
outside the building into the cylinder, and then the
As the piston continues to descend, the pressure in the
cylinder drops below atmospheric pressure, and
moisture is desorbed by the adsorbent, and heat is
conducted from the piston, cylinder walls, and cylinder
head, into the cool, low pressure air.
For the sixth stroke, the piston rises until the air has
been compressed to atmospheric pressure, and then the
exterior exhaust valve opens. The piston continues to
rise, expelling the warm, humid air to the exterior of
the building. Then, at TDC, the valve closes.
After the sixth stroke, the first stroke repeats.
||Although this idea focuses on removing humidity from a
room or building, it could be adapted to producing
concentrated oxygen, simply by using an alternative
||Depending on the results from testing, it might be
desirable to use an eight stroke cycle, where the seventh
and either strokes are identical to the fifth and sixth
strokes -- this would allow a larger volume of air per
cycle to be used for the purpose of removal of heat and
||So, on hot, humid days you end up with a massive
mound of used, hydrated silica gel (or sodium
polyacrylate) sitting in your backyard?
||Where does the energy to run this marvellous device
||I'm guessing it would work -- barely -- if it's all light
plastic. You won't get any energy out but I think it
||// mound of ... Silica Gel //
||On careful reading, we deduce that the third
part of the cycle is intended to regenerate
the silica gel.
||Thermodynamically it shoud just about work.
Yes, it absorbs rather than generates energy.
||The killer is probably that it needs to operate
at very low cyclic speeds to allow all the
themal transfers to occur. An ICE doesn't rely
on thermal transfer between the working
fluid and the structure of the engine; this
sounds more like a reverse Newcomen
||A six-stroke steam-_injection_ ICE has already been built,
pressurizing the moisture generated by the combustion to
both power the additional rotation and to clean the
cylinder. That makes sense, and it works.
||This idea makes sense in an utterly impractical sort of
way, and I'm not all that sure it would actually run. The air
compression with no power gain on the sixth stroke might
be enough to stall the engine at idle--unless the third
rotation is cut out at idle and only occurs at running speed.
||I can't recall off the top of my head the name of the guy
who built the 'six-stroke steam-assisted'; he's a famous
race engine designer from the Southwest US. He once
converted a 6-cylinder Mercedes engine into a two-stroke
"just to hear what it would sound like." Anyone know who
I'm talking about?
||Bruce Crower of Crower Cams.
||Voice -- it's not supposed to move by itself or generate
mechanical power; it is externally powered by an
electric motor (or other prime mover), and consumes
||8/7 -- In an ICE, thermal transfer between the working
fluid is and the structure of the engine, while generally
undesirable, is the source of the vast majority of the
heat which is dissipated through the engine's radiator.
This, in turn, is roughly equal to the amount of
mechanical power that the engine produces. Since it
occurs in such high quantities in an ICE, it ought to
occur in reasonable quantities in this invention.
||Alterother -- this engine isn't designed to run by itself,
but needs to be spun by an outside source of mechanical
power. It's not a prime mover. I call it an engine
because it looks much like one, and has many parts in
||And the guy who's six-stroke water-injection steam-
expansion engine got printed in Popular Mechanics, and
who converted a Mercedes five-cylinder engine to a two-
stroke was Bruce Crower.
||I get it now. I misunderstood the introduction. Thank you
both, as well, that's the man and the article I was thinking
||Thanks heavens you got this idea, goldbb! I am developing a mechanism for my rotary engine using Oxyfuel combustion process for two years already. But there's one big hurdle though that I am uncertain--Do Oxygen chemical adsorbents operating at 800 deg. Centigrade fast enough to operate in 10,000 cycles/minute?
||It's ideal for me to go to Chemistry literature regarding Oxydation-Reduction processes and ideal compounds involved, but my schedule might even get tighter. I am bogged down with way too much Mechanical Engineering literature at hand. It's definitely practical for me to solicit your expert opinions regarding this matter.