Tesla's Ambient Heat Engine Theory - Right or Wrong ?

[vasik041]

May be this helps...

[Tom Booth]

May be this helps...

Well... seems rather light on thermodynamic principles.

One thing I've found interesting lately are articles on various websites regarding compressed air and heat reclamation.

ex: "as much as 100% of the electrical energy used by an industrial air compressor is converted into heat"

http://us.kaeser.com/Products_and_Solutions/Rotary-screw-compressors/heat-recovery/default.asp

"In fact, 100% of the electrical energy used by an industrial air compressor is converted into heat"

http://kaesertalksshop.com/2013/09/18/turning-air-compressors-into-an-energy-source/

Figures vary slightly, usually a little more conservative, like 96% or 98% etc. but all these are conventional sources of information not "free energy" sites.

If that 100% heat can be reclaimed and utilized... There is still the compressed air... waiting to expand and do some work.

Doesn't this show up an obvious potential for "overunity"?

I think it is misleading though to say that the electricity is converted into heat. The heat is already in the air. Compressing the air so-to-say squeezes out the heat. The compressed air is then something like a compressed spring ready to re-expand once released from confinement. This re-expansion takes place at the expense of the air's own internal energy, the result being that the air thus released turns bone-chilling cold.

If 100% of the energy used to compress the air can be made available for use to compress more air, and the air being released can run a turbine or pneumatic engine of some kind (which results in additional cooling converting even more of the air's internal energy into mechanical/electrical energy) and the resulting cold can be utilized to deepen the "cold hole" or sink to make the heat engine/compressor even more efficient...

Further... the compressed air could be stored for a time and expanded through a simple solar collector (pipes painted black under glass) Not that I think that is even necessary, but while we are at it, why not?

What am I missing here that makes extracting solar heat/energy from the air impossible?

The problem with air-compressors is generally how to keep them cool. Cooling fins, water jackets, radiators, fans, anything to get rid of all that damn excess heat so the compressor pistons don't seize.

I don't think all that damn nuisance heat comes from the electricity used to run the compressor. That heat is solar energy being squeezed out of the air like water out of a wet sponge. The problem is that in a conventional compressor this heat is looked at as a problem. So also the cold produced from the expanding air which can form ice and clog up conventional air tools necessitating the addition of antifreeze to the air line.

"Water in the air is the cause of freezing at exhaust ports of (air) drills, pumps, etc., since the sudden expansion of the air on exhaust produces such a low temperature that ice is formed and the exhaust is clogged, oftentimes even in warm weather."

Compressed Air: A Reference Work on the Production, Transmission, and Application of Compressed Air; the Selection, Operation and Maintenance of Compressed-air Machinery; and the Design of Air Power Plants  - -Lucius Irving Wightman pg. 116

Both of these "problems", the super-heated compressed air and the sub-zero cold exhaust air from any kind of pneumatic engine running on the compressed air are no problem really if that extreme heat and cold are utilized to provide the necessary temperature differential to run a heat engine.

Compressed air can be used to produce extreme heat as well as extreme cold and without any need for any phase change.

[memoryman]

very good discussion so far; however I found several wrong or incomplete statements in these posts.
For example, in the most recent one by Tom Booth: "Compressed air can be used to produce extreme heat" is backward; extreme heat can be produced by compressing air.
Will address them in a follow-up post.

[Tom Booth]

very good discussion so far; however I found several wrong or incomplete statements in these posts.
For example, in the most recent one by Tom Booth: "Compressed air can be used to produce extreme heat" is backward; extreme heat can be produced by compressing air.
Will address them in a follow-up post.

I agree, in that I miss-stated. More properly IMO compressing air releases the heat already in the air. Again IMO the mechanical or electrical energy used to compress the air is not lost as heat. Air is elastic, like a spring. When you compress a spring it also releases heat but the energy used to do the compressing is stored as potential energy to be released when the spring is loosed from confinement, at which point the spring gets colder to some degree. In practice this release of heat from a compressed spring is not really noticeable as it is lost to the surroundings immediately. Air is much more elastic and the heat released is more noticeable but I think that the principle is the same.

IMO the heat released by compressing air is not, at least not all, due to the energy input being converted to heat. Some of that energy input, if not all of it, is stored as potential energy. The heat released by compression is, I think, MOSTLY the airs own INTERNAL energy. There is still MORE internal energy to be had when the air is allowed to re-expand, at which point it gets very cold - far below ambient. I think the fact that the air will of itself re-expand to its original volume when allowed to and that it gets very cold in the process is proof that it's own internal energy was lost during compression rather than the energy used to compress it being converted into heat.

I suppose heat is heat and making a distinction between the heat of compression, due to conversion of the energy input into heat and the air's own pre-existing internal heat (Atmospheric heat of the air having been heated up by the sun) is just a matter of how you look at it, But IMO it is more correct, or more in accordance with reality to say that the majority of the heat released by compressing air is SOLAR ENERGY that was stored in the air while the effort put into compressing the air is actually stored as potential energy as in any elastic substance or spring.

This heat recovery site claims that it is possible to reclaim up to 105% of the electrical input energy used to compress air:

http://www.atlascopco.com/useyourenergytwiceus/useenergytwice/useyourenergytwice/

The unique design of the cooling system of the ZR oil-free screw compressor with energy recovery allows to fully capture all this heat from the compressed air and oil system.
As a result, the total energy recovered as hot water amounts up to 80-105% of the electrical input energy, depending on the site conditions. (emphasis added)

They provide their own explanation for how this is possible.

But let us not forget that AFTER all this heat energy released during compression is recovered there is still the compressed air itself to be used as a power source to run pneumatic devices, air tools etc.

First of all, I'd have to say that it is impossible to reclaim 105% of the electrical input as heat. The additional 5% has to come from somewhere else, but there is also additional potential energy in the compressed air now stored in an air tank ready to do work. That is extra energy unaccounted for. It has to be coming from somewhere.

Or should we just suppose that 105% figure is some sort of misprint or exaggerated claim?

They claim: "Through the compression process, part of the energy is lost as radiation. Atlas Copco's Energy Recovery unit is able to extract an amount of energy from compressed air that is equivalent to the amount of energy that the electric motor uses. 
The most common uses for the recovered energy include process heating, space heating and water heating. "

http://www.atlascopco.us/usus/service/k/stationarycompressors/050%20save-energy/3558502/

The testing process involved the real-time measurement of the electrical input power and the output power as hot water. It was proven that... 100% of the electrical input power could be recovered in the form of hot water.

http://www.atlascopco.com/microsites/images/use%20your%20energy%20twice_tcm758-1324420.pdf

Again, if 100% (or more) of the heat generated from compressing air is recoverable in actual practice under certain conditions, there is still the potential energy latent in the compressed air itself ready to do work. How is this accounted for?

is the claim that you can "use your energy twice" just poppycock?

An LTD type Stirling Engine can use very low grade heat. I really do believe that with the right design it could be demonstrated that a Stirling combined heat-engine/compressor could extract enough heat (and cold) from compressed air to run itself with additional power to spare.

Probably not without some precision engineering though. The testing I've been able to do with very crude tin-can devices shows some promise I think, but...

I suppose like most people, if I had the money to invest in such a project I wouldn't be interested in "Free Energy" in the first place.

"The best thing a man can do for his culture when he is rich is to endeavor to carry out those schemes which he entertained when he was poor" - Thoreau

[memoryman]

Tom, compressing gas partially converts energy from the compression process to heat; similarly to friction losses. If the compressed gas is in a perfectly insulated container, than no (heat)energy is wasted or lost.