Jump to content
Science Forums

Nikola Tesla Vs. The Second Law Of Thermodynamics


TomBooth
 Share

Recommended Posts

I became interested in Stirling heat engines many years ago, then a friend who was a military contractor asked me to help design one.

 

I did. But some DOE (I think) people he talked to said that it wouldn't work because it violated the second law of thermodynamics.

 

Years later, while trying to figure out what was supposed to be wrong with my design, which I still think is probably perfectly good, I happened upon an article by Nicola Tesla from 1900 Century Magazine called "Increasing Human Energy" which was all about methods of harnessing energy, but in particular, heat engines and how the statements of Carnot and Kelvin (Lord Thompson) Early formulations of the second law, were not valid or applicable under all circumstances, and went on to innumerate several, but in particular, a novel heat engine that ran on an artificially produced sink or "cold hole".

 

According to Tesla, due to the fact that heat is not a fluid, as had previously been believed, but a form of energy, a "perfect" heat engine would not allow any heat to pass through to the sink.

 

A Stirling heat engine, running on ice, for example, would convert the heat flowing into the engine into mechanical motion before it could reach the ice.

 

I had also thought a Stirling engine would run better without a sink, or with it's cold side insulated, because a Stirling engine is really a kind of refrigerator and doesn't need an external sink, it actually creates it's own cold by converting the energy of an expanding gas into "work", which conversion disappears the heat, leaving "cold".

 

I had designed my own engine on the same principle Tesla was describing. It was a combined hot air engine and air cycle refrigerator.

 

Tesla's article can be read here:

 

https://www.unz.com/print/Century-1900jun-00175

 

and probably elsewhere. The relevant section begins on page number 200 under the heading "A Departure From Known Methods".

 

I could not find any historical or modern reference to any actual experiments conducted to test Tesla's assertions. The proposition seems fairly straightforward. It could be fairly easily tested, just run a Stirling engine and take away the sink, or run an engine on ice. If Tesla was right, the ice should take a very long time to melt, or might not melt at all.

 

So not finding any history of any actual experiments, I recently sent away for several Stirling heat engine kits to run various experiments I've been thinking about doing for a long long time.

 

The results are rather interesting I think. And seem to indicate that Tesla may have been absolutely correct in his assumptions. And, maybe my engine would work after all.

Link to comment
Share on other sites

In that article Tesla wrote:

 

(Edited for length and relevance)

 

"Heat, like water, can perform work in flowing down,... But can we produce cold in a given portion of the space and cause the heat to flow in continually? To create such a "sink," or "cold hole," as we Might say, in the medium, would be equiva-

lent to producing in the lake a space either empty or filled with something much lighter than water. This we could do by placing in the lake a tank, and pumping all the water out of the latter. We know, then, that the water, if allowed to flow back into the tank, would, theoretically, be able to perform exactly the same amount of work which was used in pumping it out, but not a bit more.

 

Consequently nothing could be gained in this double operation of first raising the water and then letting it fall down. This would mean that it is impossible to create such a sink in the medium. But let us reflect a moment. Heat, though following certain general laws of mechanics, like a fluid, is not such; it is energy which may be converted into other forms of energy as it passes from a high to a low level.

 

To make our mechanical analogy complete and true, we must, therefore, assume that the water, in its passage into the tank, is converted into something else, which may be taken out of it without using any, or by using very little, power... If the process of heat-transformation were absolutely perfect, no heat at all would arrive at the low level, since all of it would be converted into other forms of energy."

 

I think, from previous discussions on this topic, it may be necessary to clarify what actually constitutes an "absolutely perfect" heat engine.

 

I'm often told in these discussions, and there have been many, that "no heat engine is 100% efficient" and citing the formula for calculating Carnot efficiency, a typical Stirling type heat engine may be found to be maybe 18% efficient. And, that's not including losses due to friction, heat losses by conduction, etc.

 

And I'm told that this means that, at best, only 18% of the heat that goes into a Stirling heat engine is converted into useful work. The other 82% of the heat is "rejected" to the cold sink.

 

It is also frequently stated that a heat engine, to be "absolutely perfect", would have to operate at zero K.

 

Here is a typical example:

 

https://youtu.be/_n3Z_YBzvDQ

 

Does anyone besides me, see any kind of problem here?

 

Tesla's definition of perfect efficiency meant "no heat at all would arrive at the low level". What is the low level?

 

Typically the "sink" or "cold reservoir" for an operating heat engine, the "low level" is ambient. On a warm summer day, call that 300 Kelvin.

 

The "high level" would be however many degrees above ambient are applied to the engine. Let's say we are running a model Stirling engine on a cup of boiling water. About 373 K.

 

So we have a temperature difference of 73 degrees. A "perfect" heat engine then would utilize All of this added heat, converting it to work, bringing the temperature of the gas back down to ambient at 300 K.

 

Such a "perfect" heat engine, BTW would have a "Carnot efficiency" of just 9%

 

There is some serious cognitive dissonance going on here, isn't there?

 

We all know heat flows from hot to cold so at ambient temperature, heat would cease to flow to an ambient sink

 

If the engine is at ambient, then only heat added however many degrees above ambient will begin to "flow" into the engine, if all that heat is converted to work, there would be a return to the ambient baseline of around 300K NOT ABSOLUTE ZERO!

 

So called "carnot efficiency" is complete nonsense, is it not? It has no actual applicability to heat engine efficiency. It's simplistic nonsense.

 

Yet, what is seen in the example video above is universally promulgated as gospel truth. To be 100% efficient a heat engine must operate at absolute zero. And we all know that's impossible, so you can be "Absolutely certain" if anyone ever tells you that they have a heat engine that uses all the heat you can give it, "that engine is NOT REAL".

 

Everybody remember that. It is a Law of nature, what Tesla proposed can never ever happen. Anyone who says they have made such an engine is a con artist. A liar, or a nut, or simply mistaken.

 

"IT IS IMPOSSIBLE". Case closed.

 

Anyone who takes Tesla's rant seriously will be a laughing stock. There is, of course, therefore, no point whatsoever making any effort to experiment with Tesla's idea, everyone knows it is patently rediculus. So don't waste your time.

 

Right?

 

I posted video of my experiments to two other science forums recently for comment and my threads were locked or I was banned.

 

Really?

 

Browsing around, this forum seems like there might at least be not quite such a rush to judgement when presented with something that is not on the high school science curriculum.

Link to comment
Share on other sites

And, an example post from here on the forum. The sort of argument I've heard repeated over and over a hundred times. "Just don't bother trying..."

 

http://www.scienceforums.com/topic/4978-why-is-the-carnot-cycle-the-most-efficient-heat-engine/?p=333126

 

But is it really true?

 

Does an engine have to have a sink at absolute zero to be 100% efficient?

 

No.

 

A toy engine from eBay could be 100% efficient operating on a cup of coffee at 9% "carnot efficiency".

 

I don't know exactly where or when someone decided that a 100% efficient engine had to utilize ALL HEAT IN THE UNIVERSE, but is not that exactly what 100% carnot efficiency really means? How utterly rediculus is that?

Link to comment
Share on other sites

Tesla was not very good at physics but a brilliant experimenter. A perfect heat engine is forbidden just as there is no perfect refrigerator in physics. A good example is an extremal black hole particle, if one was capable of existing in the ground state then it would be a perfect refrigerator that would violate the laws of thermodynamics (ie. Hawking radiation would break down). At best, we can speculate that the black hole is only the closest thing we have to an ideal black body heat engine.

Edited by Dubbelosix
Link to comment
Share on other sites

There is one curious prediction now experimentally varified, two particles entangled can violate the second law, so two black hole particles in my writings I explain could violate the second law which is worrying if we ever produce them in accelerators since particles are made in pair production.

Edited by Dubbelosix
Link to comment
Share on other sites

And, an example post from here on the forum. The sort of argument I've heard repeated over and over a hundred times. "Just don't bother trying..."

 

http://www.scienceforums.com/topic/4978-why-is-the-carnot-cycle-the-most-efficient-heat-engine/?p=333126

 

But is it really true?

 

Does an engine have to have a sink at absolute zero to be 100% efficient?

 

No.

 

A toy engine from eBay could be 100% efficient operating on a cup of coffee at 9% "carnot efficiency".

 

I don't know exactly where or when someone decided that a 100% efficient engine had to utilize ALL HEAT IN THE UNIVERSE, but is not that exactly what 100% carnot efficiency really means? How utterly rediculus is that?

 

 

In trying to find universal references for the physics equations we use, scientists sometimes need to be a bit creative.

 

A good example is the equation for gravitational potential. Suppose while standing on the surface of Earth, you lift a rock above your head. Maybe you know the rock has gravitational potential of - GM/R but you want to know where this potential is zero. You might imagine a deep hole to the earth’s center and say that is where the gravitational potential is zero. But If you were on a Jupiter-sized planet you would need to dig a much deeper hole! Obviously, the distance to the center of the earth cannot stand in as a universal reference. Then what can be used? How about infinity? Indeed, infinity is the reference point where all gravitational potential is said to be zero, and this works everywhere so it is a universal reference.

 

 As Wikipedia saysThe potential has units of energy per mass, e.g., J/kg in the MKS system. By convention, it is always negative where it is defined, and as x tends to infinity, it approaches zero.”

 

But I can hear you say, “how can that be since the potential should decrease as something falls”. True. That is the reason for the negative sign in - GM/R. Zero is the greatest value that a negative number can have!

 

Now ask yourself what can possibly be used as a universal reference for the efficiency of all heat engines? If you think 0 Kelvin is bad, you should be thankful the scientists did not decide to use infinity! :shok:

 

The fact is, there is no better universal reference for all heat engines than 0 K even if no practical heat engine can ever reach that T. Can you think of a better one?

Link to comment
Share on other sites

In trying to find universal references for the physics equations we use, scientists sometimes need to be a bit creative.

 

A good example is the equation for gravitational potential. Suppose while standing on the surface of Earth, you lift a rock above your head. Maybe you know the rock has gravitational potential of - GM/R but you want to know where this potential is zero. You might imagine a deep hole to the earth’s center and say that is where the gravitational potential is zero. But If you were on a Jupiter-sized planet you would need to dig a much deeper hole! Obviously, the distance to the center of the earth cannot stand in as a universal reference. Then what can be used? How about infinity? Indeed, infinity is the reference point where all gravitational potential is said to be zero, and this works everywhere so it is a universal reference.

 

As Wikipedia saysThe potential has units of energy per mass, e.g., J/kg in the MKS system. By convention, it is always negative where it is defined, and as x tends to infinity, it approaches zero.”

 

But I can hear you say, “how can that be since the potential should decrease as something falls”. True. That is the reason for the negative sign in - GM/R. Zero is the greatest value that a negative number can have!

 

Now ask yourself what can possibly be used as a universal reference for the efficiency of all heat engines? If you think 0 Kelvin is bad, you should be thankful the scientists did not decide to use infinity! :shok:

 

The fact is, there is no better universal reference for all heat engines than 0 K even if no practical heat engine can ever reach that T. Can you think of a better one?

Zero is the greatest negative number? The smallest negative number is -1 and zero is not a number.

Link to comment
Share on other sites

Zero is the greatest negative number? The smallest negative number is -1 and zero is not a number.

 

 

LOL What?

 

Is zero a number?

 

"The simple answer: Yes, of course zero is a number. (I’m giving you the benefit of the doubt and not saying, “you dolt.”) What, you think it’s maybe an animal or vegetable?"

 

I didn't say that zero is a negative number. What I said is zero is the greatest value that a negative number can reach.  IOW, as negative numbers increase in value, they approach zero as a limit.

 

0 (zero) is a number

Edited by OceanBreeze
Link to comment
Share on other sites

Not in the sense you meant, zero is not a negative number, it no more the highest positive number than it is the highest negative number.

 

 

Obviously, you didn’t even understand the sense that I meant.

 

It should be very clear to just about anyone (except you) that the context I brought this up in, is that gravitational potential goes to zero as distance goes to infinity. That is, gravitational potential is at the highest possible value at infinite distance and decreases as distance decreases because it is a signed negative number.

 

Read the Wiki link I gave  “The potential has units of energy per mass, e.g., J/kg in the MKS system. By convention, it is always negative where it is defined, and as x tends to infinity, it approaches zero.”

 

All negative numbers are less than zero. What part of that do you not understand?

 

You said “The smallest negative number is -1 and zero is not a number”

 

You are wrong on both counts.

 

Zero is most certainly a number and there are an infinite amount of negative numbers that are smaller than -1.

 

Maybe this will help you?

 

“Negative numbers are smaller than zero. Negative numbers get smaller and smaller the farther they are from zero. This can get confusing because you may think that –400 is bigger than –12. But just think of –400° F and –12° F. Neither temperature is pleasant to think about, but –400° is definitely less pleasant — colder, lower, smaller. When dealing with negative numbers, the number closer to zero is the bigger number”

 

 

Now, can we let Tom Booth have his thread back?

Link to comment
Share on other sites

In trying to find universal references for the physics equations we use, scientists sometimes need to be a bit creative.

 

(...)

 

The fact is, there is no better universal reference for all heat engines than 0 K even if no practical heat engine can ever reach that T. Can you think of a better one?

I think the problem, (though I sometimes feel like I'm the only one on the planet who happens to notice it as a problem), is that measuring scales are being confused or swapped out, one for the other.

 

Take for example, if I say "water freezes at zero degrees". If in the course of conversation someone carts out a different temperature scale than the one I was using, obvious problems arise mathematical, philosophical, logical problems of all sorts. Confusion and argument ensues.

 

What I want to make clear is that in speaking about a "perfect" conversion of heat to other forms of energy, Tesla was using a logical, not a fixed temperature scale.

 

Logically, If it is 300 Kelvin in the ambient environment and I apply heat to a heat engine using boiling water at 373 K on a logical scale, my base temperature or starting temperature can be considered zero (300 K), from there the temperature of the engine was raised 73 degrees.

 

In Tesla's article, a "perfect" heat engine would utilize all of the heat applied to the engine until the "exhaust" temperature was 300 K, or the baseline ambient starting temperature.

 

Such a "perfect" heat conversion machine could, on such a logical scale, be legitimately recognized as 100% efficient, though the cold "exhaust" side of the engine is NOWHERE NEAR absolute zero.

 

So I might say I found a 100% efficient engine, on such a logical scale and this could be true, but then someone says "No heat engine is 100% efficient" using "Carnot efficiency" on an absolute temperature scale.

 

This is apples to oranges

 

On what I'm calling a "logical" temperature scale, my toy model engine may appear to be 100% efficient, though at the same time that perfect 100% efficient engine; it may be pointed out; is only 9% efficient, (ignoring losses, like friction etc) Nowhere near 100% efficient.

 

This completely false comparison, however, is very frequently used as one of the standard methods for dismissing or debunking any evidence of apparent near 100% heat engine efficiency.

 

It is not a matter of which scale of measurement is "better". Any measuring scale can be useful for some purpose, or under some circumstances, but using an absolute temperature scale as a measure of heat engine efficiency is misleading as MOST PEOPLE who think about heat engine efficiency in a practical way, think about it on a logical scale in terms of heat added to the system above equilibrium.

 

To say that a "coffee cup" Stirling engine operating between boiling water (373K) and ambient (300K) at 9% Carnot efficiency is "rejecting" 91% of the heat to the sink or that more than 90% of the energy is "passing through" the engine to the sink is COMPLETELY FALSE!

 

Inevitably, this argument will be presented though, it is taken as gospel and without question that nearly all the heat put into a heat engine simply passes right through, like water through a turbine, largely unchanged, and that some cold sink for the heat to flow into is an absolute necessity, or a heat engine cannot operate.

 

Tesla tried to point out this fallacy in 1900, saying that heat is not a fluid like water, flowing from a high to a low level, ALL arriving at the low level, like water flowing from one reservoir to another lower reservoir.

 

Heat is a form of energy. 80% or 90% of the heat being utilized by a heat engine to produce work does not pass through to the sink. This misconception is the result of confusing logical and absolute temperature scales.

 

In actuality "Carnot efficiency" as standardly calculated IS THE SAME THING as 100% "logical efficiency".

 

Carnot efficiency is, (under normal circumstances), the absolute best a heat engine could do if it utilized ALL the heat applied to it ABOVE equilibrium, bringing the exhaust temperature down to the ambient baseline, or cold side baseline temperature. That is, back to equilibrium.

 

This limitation is because, even if the engine were mechanically capable of utilizing even MORE heat, brining the exhaust temperature lower than the cold "sink", that could not happen because heat always flows from hot to cold. If the engine cold side temperature ever fell below the equilibrium baseline, heat flow would reverse and the cold side temperature of the engine, rather than being cooled by the sink, would be warmed by it.

Edited by TomBooth
Link to comment
Share on other sites

Yes, it is very useful as a perfect example of what I'm talking about. From that link:

 

"Carnot’s interesting result implies that 100% efficiency would be possible only if Tc=0 - that is, only if the cold reservoir were at absolute zero, a practical and theoretical impossibility. But the physical implication is this—the only way to have all heat transfer go into doing work is to remove all thermal energy, and this requires a cold reservoir at absolute zero."

 

This complete and utter nonsense is universally promulgated as absolute fact.

 

The truth is, Carnot was a philosopher with no knowledge or practical experience with any real heat engine. There were no steam engines in France at the time.

 

Nearly everything he ever wrote on the subject was pie in the sky imaginings with no practical application whatsoever.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...