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:
-
Air is
everywhere.
-
Air contains solar
energy.
-
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.
-
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.
-
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:
-
An insulated shroud
enclosing both the compressor head and the engine head would conserve
much of the compression heat.
-
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:
-
heat pipes
-
electric resistance
heaters
-
water-cooled compressors
that dump heat into channels in the air engine block
-
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 Efficiency IN the
Use of Compressed Air to DRIVE an
Air Engine
-
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.
-
Add heat to engine air whenever possible;
first absorb ambient heat, then recover compression heat, then add
purposely generated heat, if any.
-
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.
-
Regenerative braking works well with air cars,
and compression braking saves brakes and heats the air in the
tanks.
-
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.
-
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.
-
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.
-
All compression work is lost as heat.
This little-known fact is straight out of the
textbooks.
-
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.
-
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.
-
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.
-
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)
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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