It’s almost too simple
for words. It’s so easily missed because its discovery does little
to gratify the inventor’s creative instinct, or the engineer’s hard-won
high-tech education, or the tinkerer’s love of gadgetry. New
inventions, theories, and gizmos are so unnecessary as to distract from
compressed air’s ultimate secret, which is really just efficiency,
inherent and designed-in.
Compressed air's inherent efficiency is
made evident by these facts:
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Air is everywhere.
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Air contains solar
energy.
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Compressing air is
a simple process that makes its internal energy (solar heat) usable
without altering the air chemically. No thermodynamic conversions
or changes of state are necessary, eliminating wasteful steps.
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The energy wasted
in compressing air takes the form of heat, which is air engine fuel, and
is conservable for use.
Design efficiency
is the need to go one step further than status quo convention in the
production and use of compressed air. The two-step process of
compressing and expanding air creates two opportunities to introduce
efficient design measures, that is, to conserve energy.
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Means of expanding
air can be provided to use more of the available energy before
exhausting it, by way of a relatively efficient air engine as opposed to
a commercial air motor.
-
Means of conserving
compressor work can be used to decrease the net cost of making
compressed air.
The ultimate secret
of compressed air is that to create a self-fueling pneumatic power plant,
all you have to do is make the most of the energy contained in expanding
air, and/or make the most of the energy invested in compressing air.
Simply put, the self-fueling air engine is a natural phenomenon of
ordinary processes, and not some aberration of fringe science or a result
of exotic devices. This basic fact is easily proved mathematically
using standard engineering formulas and charts. Gizmos and gadgets
are fun, but unnecessary; they are the stuff of research institutes.
The first goal should be to show an ordinary air engine running an
ordinary compressor and keeping its own tank full in the process. I
repeat: the math easily proves this possible.
The idealization of
conserving compressor work would be to put the compressor in the tank.
The fresh air brought in from outside the tank is compressed into the
tank, and the work done in the compressing dissipates into the tank as
heat, expanding the volume of air available to the engine as fuel.
The increase in fuel value due to the conserving of compression heat
represents a value beyond what one would expect from engineering charts
but not beyond the scope of ordinary engineering formulas to quantify.
The idealization of conserving expansion potential is to expand the
compressed air so slowly that its pressure never goes down, since the heat
used to push pistons is replaced by ambient heat absorbed from the
surroundings.
This is straight out of the thermodynamics textbook.
The obvious
impracticalities of these idealizations are beside the point; it remains
only to identify means of going in their general direction. For
example:
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An insulated shroud
enclosing both the compressor head and the engine head would conserve
much of the compression heat.
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A multi-stage engine
with inter-stage ambient heaters, which runs at a low RPM, would squeeze
lots of work out of a little air.
-
Combining the two
strategies could lead to the most practical design.
Gizmos can be added
later—such as reducing compression work (as opposed to
conserving the work of a normal compressor)—with a series of check
valves (and/or jet pump in the tank) that allows low pressure air to be
injected into a high pressure tank. Other possibilities include:
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heat pipes
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electric resistance
heaters
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water-cooled
compressors that dump heat into channels in the air engine block
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As a last resort,
any air engine can be made more efficient by using combustible fuel to
heat engine air till the Coefficient of Performance (COP—see heat pump
basics) rises above unity, making a hybrid power plant without the
noise, pollution, and expense of an internal combustion engine.
If not for compressed
air’s simplicity, its use in solar power production would have been
mastered long ago. We must stop flattering ourselves with our
brilliant new ideas, and prove the self-fueling nature of air with basic
designs that take advantage of air’s best feature: its ultimate
simplicity.
FROM FALSE ANALOGIES TO
FREEDOM FROM FUEL
To state that
compressing air gives it the ability to do work is like saying that
building a dam gives water the ability to operate a power-producing
turbine. While these are true statements, they are not made in the
scientific context of energy investments. It would be false to state
that the work invested in compressing air results directly in the work
compressed air can do, just as it would obviously be false to credit the
work of building a dam for the quantity of water power thus made
available. In both cases, the work done by the pressurized fluid is
a result, scientifically speaking, of the sun’s energy, while the work of
the compressor, like that of the dam builder, is an incidental
investment—you might say an economical consideration or hardware
cost—rather than a scientifically correct accounting of the energy
invested that later pays off in the power made available.
WHAT’S RIGHT WITH WHAT’S
WRONG WITH AIR
Some of air’s so-called
disadvantages, according to the usual way of looking at things—a viewpoint
that is built around using air for safety, portability, and convenience,
not for efficiency—are some of its greatest advantages.
The classic case of
this glaring discrepancy between standard thinking and air’s real
potential is the assumption that air is self-defeating in any attempt to
produce power because of the fact that it gets cold. The standard
line goes like this: air enters a cylinder of an air motor and expands,
becoming cold in the process. The air subsequently entering the
cylinder will be cooled by the cylinder walls, robbing part of its power
value before it can do any work. Effectively then, it is a
self-defeating hope to try and use air efficiently. My rebuttal is
that the cold produced by compressed air’s expansion in a cylinder is an
advantage because it makes the machinery a sponge for heat in the
surrounding atmosphere which, if absorbed into the system because of
enlightened design work, becomes free energy for the piston to use.
Let’s face it: once
Americans get even the vaguest inkling that anyone or anything could be
considered wimpy, they shun it like the plague. Could it be that the
general ignorance of compressed air’s subtle and misunderstood nature is a
result of our macho nature, our fear of being associated with sissified
ideas?
Once I called the
manufacturer of a fairly efficient compressed air motor, and when I asked
why the motor wasn’t being put in cars, the salesman I spoke to informed
me that his boss would remind me that in order for the car to go anywhere,
it would have to be followed by a semi truck carrying its compressed air
supply.
Now if that isn’t
self-defeating and wimpy, I don’t know what is. It’s downright
Unamerican to give up so easily!
Similarly, it is
thought to be ever-so ridiculous, that a compressor on-board an air car
would be the silliest notion since self-chewing bubble gum. All that
power wasted, for the little trickle of compressed air made available.
But wait a minute.
In what way is all that power used?
It is used to make
heat.
And what is it about
compressed air that makes it capable of pushing pistons?
It’s the heat.
And what is it about
expanding air that makes it seem so objectionable as a piston-pushing
medium?
The cold produced.
And what does cold do
to heat?
It sucks it up like a
sponge.
Conclusion: the hotter
air gets when it's compressed, the
more heat is available to be conserved; the colder the air gets when it's
expanded, the more ambient heat it can absorb from outside the engine.
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“...it seems nearly impossible to get the scientific establishment to
think about the very basic assumptions under which most of us scientists
operate.”
–Wes Jackson, Land
Institute, Salina, Kansas
“Today’s scientists
have substituted mathematics for experiments, and they wander off through
equation after equation, and eventually build a structure which has no
relation to reality.”
—Nikola Tesla
“Rigorous scientific
principles are what you want after you’ve made the discovery.
They’re the frame for the picture of reality that you’ve created.
But you don’t start with a frame and then fit the picture into it.
You start with a bloody great glob of inspiration and hope that you end up
with something your fellow scientists will recognise as a masterpiece.”
—Martin Sherwood,
Maxwell’s Demon
The assumption that
compressed air as an energy carrier contains a portion of the
work invested in compressing it is a false analogy.
The power available
from steam is a direct result of the power used to generate the steam.
Steam delivers, as work, a portion of the same heat energy that had just
made it steam; if the boiler were to cool to ambient temperature, no
energy would be available. This is obviously not true of hot
compressed air just pushed into a tank: after the tank cools down, its
contents still contain usable energy.
Thus, the power
required to produce compressed air is uniquely unrelated to the power
available from it later. We have always assumed, as happens to be
true for the steam used as an example above, that the work available
from compressed air is a portion of the work that had been done to
compress it.
What is this energy
that a cold tank of compressed air holds? What form of energy
does compressed air deliver? It has been our lapse in reason to
assume that the only relevant task is to make the gauge go up on the tank.
It is relevant, but not the relevant task, to make the needle rise.
The information most relevant to the task of generating compressed air is
that the energy delivered by compressed air to an engine or air motor is
heat. Heat pushes pistons, while pressure just tells us
approximately how much we can do to a given piston, depending also on
other factors such as the size of the tank and the size of the piston.
So we assume that compressed air is a direct result of the compressor’s
work because we assume the compressor is putting its own energy into the
tank.
But in
reality—according to any compressed air textbook that even mentions this
whole chronically avoided issue of Where does compressed air’s energy
come from?—the energy available from a tank full of room temperature
compressed air is the same energy that was in the surrounding atmosphere
before the air was stuffed into the tank. This is so because all the
compressor’s work was wasted generating heat. The air molecules heat
up due to friction if you try to squeeze them together. You squeeze
them together because you want the gauge to go up. But what you
should want is for two things to happen. You want the tank gauge to
go up and you want the compressor gauge to stay as low as possible
while the compressor delivers large quantities of air into the tank; the
air is then compressed-by-mixing upon finding itself inside a tank full of
pressurized air, and shares its heat energy freely with the air already in
the tank. Incidentally, this makes the gauge go up. The
everyday compressor uses 100% of its available work energy to add heat to
its surroundings, and the result is that a little bit of air gets trapped
in a tank and wants out to the degree indicated by the gauge. But
the gauge pressure in itself does not indicate how much energy is in the
tank.
The relevant goal
to always refer to in re-inventing pneumatic power systems is a variation
on one theme: mix atmosphere (and the heat it contains) with a
permanent reserve of pre-compressed air, and do this at the lowest
possible energy cost.
The result of this
process is that a large quantity of heat-bearing atmosphere finds itself
trapped and usefully pressurized at such a low energy cost that outside
work becomes possible.
The solar air
engine is just a more sophisticated version of using wind to propel a
sailboat, and it is just as revolutionary as sailing ships once were,
because it's just as groundbreaking in its implications for humans and for
this planet, and just as solar.
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Twelve
Principles of Fuel Efficiency regarding the Use of Compressed Air to
Deliver Energy to an Air Engine
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To obtain maximum use of air’s internal
energy (ambient heat), do not allow the air that goes to the first power
stage in a multiple stage expansion to rise in temperature above
ambient. Maximum practical cold production can be reached by means
of first stage expansion with early cutoff, then heat can be added.
Some heat (toward ambient but not above) should be absorbed just before
first stage intake, such as electric heating pads on elbows where cold
is naturally produced, and other places where expansion takes place as
the air approaches the engine.
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Add heat to engine air whenever
possible; first absorb ambient heat, then recover compression heat, then
add purposely generated heat, if any.
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Reheating compressed air to raise
pressure just prior to engine intake is much cheaper in energy cost than
an equivalent pressure increase attained by compressing more air.
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Regenerative braking works well with air
cars, and compression braking saves brakes and heats the air in the
tanks.
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It takes less work to increase the
pressure of a volume of air from 100 to 200 psi than it would take to
increase the same air from 0 to 100 psi. This can be verified by
looking at any air compressor power consumption chart ever published.
It is the rationale behind the closed cycle pneumatic power plant, which
can do more work with smaller machinery.
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Any chance to boost the pressure of
already compressed air instead of compressing atmosphere will lower the
relative size of the machinery needed to do that task, because more
energy per unit volume of compressed air is handled by a booster than by
a normal atmosphere compressor with the same displacement.
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It is possible to put low pressure air
into a high pressure tank against very little resistance by taking
advantage of the Bernoulli Effect, which is the answer to the 1870
physics riddle known as Maxwell’s Demon. Potential and kinetic
energy can be caused to trade places so that each is used for what it
does best, and neither gets in the way of the goal, which is to keep the
tank full as cheaply as possible.
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All compression work is lost as heat.
This little-known fact is straight out of the textbooks.
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The energy that pushes pistons is heat,
not pressure, so if we arrange to use solar-source heat to run an air
car, then the air car is a self-fueling solar air car.
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The longer cold, partially expanded air
stays in the engine, the more free heat it will absorb from its
surroundings. To keep it moving slow, behaving more like a heat
sponge, try the following: lower rpm, multiple-stage (compound)
expansion, heat exchangers (no bends in piping) between stages.
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Extra pressure needed for any reason as
a part of the power process should be generated only as needed so that
compression heat can be used immediately and storage pressure can be
kept to a minimum. The more air you store in a given space, the
higher the maximum storage pressure becomes.
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Find ways to use compressed air at its
full pressure, such as jet pumps and other pressure exchangers.
Design around this concept, rather than using regulators to lower the
air's pressure to that desired.
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How to Double
the Power Value of a Dollar's Worth of Compressed Air,
by Spending Only 10 Cents
Excerpt from
“Compressed-Air Motors," Harper's Weekly, December 5, 1896
When compressed air
was first tried, it was found that the loss of power was enormous. It was
difficult to store, for the air leaked rapidly away; it was expensive to
generate, and there were thermo-dynamic difficulties in its use without
number. When a thousand cubic feet of air is jammed into the space of one,
a large amount of heat is developed, and in order to store and use the air
this heat must in some way be drawn off. Similarly, air at high pressure,
when released, cools rapidly. The result, if there be a sufficient
moisture, is freezing and clogging. For a long time it was thought these
difficulties were largely insuperable.
Now, however, these
very difficulties are turned to a profit—to such excellent profit, indeed,
as to afford an apparent paradox. It seems idle to assert that it is
possible to get as much power out of a machine as you put into it—this
means a frictionless and wasteless mechanism. And yet a very near approach
to just this condition seems to have been made in the case of compressed
air. This is due to the development of the reheating process. Lest the
reader be not familiar with the technique of the subject, it may not be
idle to explain its broader features. In the process of compression the
air is sucked into a piston, and then rammed into a reservoir surrounded
by a water jacket, the latter drawing off the heat generated in the
compression. The machine which does this work is a beautiful affair of
what is known as the four-stage type. That is to say, the air is first
driven up to about eighty pounds pressure and cooled; then turned into a
second cylinder, where it is compressed still further, then cooled again;
and so on up to the desired point. Thus even at two or three thousand
pounds pressure to the square inch the air within the reservoir remains at
somewhere near the temperature of the outside atmosphere. But if the air
be used in this condition, not only will a large share of the power
employed in compression be lost, but it will, as already noted, have a
tendency to freeze everything within reach. If, however, as it is
released, it is passed through a heater or is shot through superheated hot
water it will, under the well-known properties of air, enormously expand.
In actual practice it has been found possible to add, by reheating, one
horse-power to each horsepower developed by compression, at one-eighth or
one-tenth the original cost of the latter. That is to say, if a given
quantity of compressed air costs a dollar to generate, the further
expenditure of ten cents in reheating will double its power to do work.
Theoretically the total efficiency thus obtained is actually greater than
if the same amount of coal had been burned in an ordinary steam-engine and
the power thus generated used direct. In practical use it is slightly
less.
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BOB NEAL'S U.S. PATENT NO. 2,030,759:
COMPRESSION UNIT PUTS LOW PRESSURE AIR
INTO A HIGH PRESSURE TANK (1936)
(click thumbnail images for full size,
high resolution images. to print these images on one sheet, instead of how
your internet browser wants to do it, DOWNLOAD THEM FROM GOOGLE PATENTS OR
THE U. S. PATENT OFFICE)
When the
Patent Office informed Bob Neal that his patent claim would be denied
because it was a perpetual motion machine, he built a miniature working
model, put it in a suitcase, and flew to Washington DC.
He plopped
the engine down on the patent commissioner's desk, turned it on, and
requested that he be granted his patent on the basis that the engine
worked. His request was granted. When the patent came out he
was visited by German officials who requested that he share his secret
with them. Their request was not granted.
The
visiting Nazis kidnapped Bob Neal's daughter, and once again requested
that he share his secret with them. He took his working models apart
and scattered the pieces around the countryside. He informed the
Nazis that he was through with the engine forever, and requested that they
return his daughter, which they did.
That was a
few years before the U.S. entered the second world war. Toward the
end of the war, the Germans perfected their pulsejet rocket, which might
have been inspired in part by Bob Neal's patent, since it has the same parts as the
mysterious equalizer that allows low pressure into his air tank.
However, the pulsejet basics were patented long before that.
Since 1980 I've been trying to design and/or build an air tank that
would admit lower-than-tank-pressure air into it. My latest design
is detailed in my webpage called Neal Tank.
My search
for Bob Neal's secret inspired the several collections of research
findings in my catalog that describe machines whose functioning depends on
sound waves.
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HOW THE
MISINVENTION OF THE AIR ENGINE
GOT US TO WHERE WE ARE TODAY:
WITH AN AIR ENGINE THAT BURNS GASOLINE
In 1670, Christiaan
Huyghens devised the first-ever engine, made up of a cannonball acting as
a piston in a vertical cylinder. An explosion of gunpowder under the ball
raised the ball up the vertical cylinder, then it would fall back down the
cylinder under its own weight. This pumping engine worked because of the
suddenness of the motion imparted to the cylinder's contents by the
explosion. Behind the high pressure explosion pushing the ball up the
cylinder, there was an implosion, a sudden state of partial vacuum or
rarefaction wave, in the cylinder. Because of the sub-atmospheric
pressure, or depression, in the cylinder, the atmosphere added its own
energy to this engine cycle to force the next cylinderful of water into
the rarefied space under the ball. Then the ball fell back down the
cylinder, pumping the water back out. Each explosion would scavenge the
cylinder by clearing it of any water left over from the last cycle, by
means of a high pressure blast or compression wave.
Huyghens' basic
discovery--the depression left inside a closed cylinder after a sudden
outward pulse--was the working principle that Thomas Savery used in taking
the engine to the next stage in its development. The alternating wave in
the pumped fluid was a fluid piston that did the pumping. Pulses of steam
alternately scavenged the two chambers of Savery's engine, and each
chamber would automatically refill with water because of the depression
left behind each scavenging pulse. Savery's engine had no moving parts
except valves. The mass exit of the chamber's contents left a depression
that induced the next chamberful of water, and a pulse of steam pumped
this water out. The pulsometer pump, which was manufactured from 1876 to
at least 1938, used the same principle.
Newcomen's and
Watt's cumbersome piston engines, laden with moving parts, took precedence
in the developing engine industry over the simpler fluid piston principles
that Huyghens and Savery pioneered. This was, in effect, an early version
of engineered obsolescence. If we hadn't been in
such a hurry to get in our cars and go, the pulse pumping engine might
have gotten there first, in which case we'd all be driving air cars right
now. Instead, compressors were designed to look like piston engines.
Bob Neal's patented
Compressor Unit is the basic idea of the essential hardware needed to run
a self-fueling air car. Neal filed his patent in 1934; a trip to
Washington with the working model secured him a patent in 1936; shortly
thereafter he had to abandon the project due to harassment by the Nazis.
The Nazis perfected the pulsejet engine in 1943; the French were
developing their own pulsejet at the same time. This pistonless piston
engine--a tube containing a resonant fluid piston--proved to be the most
powerful engine for its size that was ever built. And none of the
pulsejet's inherent defects, such as high noise levels or wasted residual
energy in the exhaust (or the fact that it propels bombs), apply to Neal's
equalizer. since the equalizer is inside a tank full of compressed air.
Michel Kadenacy
filed the first of his French patents on August 1, 1933. Kadenacy's system
of acoustically scavenging and charging an engine cylinder is still the
theory behind twostroke engine tuning. The Kadenacy Effect could be
called the Huyghens Effect, but Huyghens already had a principle named
after him, also having to do with waves. The work of Huyghens became the
foundation for the work of James Clerk Maxwell, the founder of
mathematical prediction in theoretical physics, who described symbolically
the future discovery of dynamic pressure exchangers--Maxwell's Demon--in
his textbook Theory of Heat in 1870.
Arkansas shoemaker
Bob Neal's compressor unit is Maxwell's Demon reduced to hardware, and
it's also the logical idealization of Huyghens' firstengine-in-history.
As a solar heat pump within a Thermodynamic Generator it ranks as the
oldest of new ideas. "The Neal Equalizer as Energy Sponge" will one day be
considered a refinement in engineering thought that paved the way for the
age of sustainable technology to take hold in the 21st century.
Meanwhile, the
Earth is still flat.
* * * * * *
“For very large conspiracies to work over
large geographical areas and for decades at a time, the conspiracy must
be transformed into something else—a belief system, an ideology, a world
view, a concept of proper professional behavior, even a crusade.”
—Angus Wright, The Death of Ramon Gonzales: The
Modern Agricultural Dilemma
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