Tesla's "Ambient Heat Engine" Experiment

[Tom Booth]

A while ago I was looking online for any kind of really super insulating material. Preferably something strong and light.

I came across a company that manufactures glass microspheres. Tiny hollow glass beads with a vacuum inside. Could be incorporated into something like Portland cement or firebrick clay. The idea at the time was to make a light weight fire proof displacer, for a high temperature engine but of LTD type design, for a wood stove Stirling.

But, it could also make a superior insulation for this - ice engine in the oven - type experiment.

The manufacturer sent me three gallon containers of various grades of this stuff for evaluation.

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I haven't gotten around to using it yet though. But I do very much appreciate the free samples!

[Tom Booth]

Maybe for the oven experiment, the ice could be inside some of this Starlite stuff.

I think it only works good if it is burned with a very high heat to produce a carbon foam first.

In another video this Starlite stuff even survived the thermite test.

https://youtu.be/0anEMZs9zHE

The problem with the oven test is mainly that my toy Stirling engines are mostly plastic (acrylic), styrofoam and rubber.

How hot exactly do you want the oven to be?

It might survive 200°F to 250°F or a little more. The melting point of acrylic is about 320°F not sure about the styrofoam displacer. Much less probably.

Hotter than about 250°F I'd have to build a more heat resistant model.

[Tom Booth]

Here is a clue regarding what may be the main secret carbon ingredient in Starlite:

https://youtu.be/aqR4_UoBIzY

https://youtu.be/aqR4_UoBIzY

Maurice Ward, the inventor of Sarlite, who took his secret to the grave, was a hair dresser.

I just asked my wife what was in hair spray, she asked back "what?".

I said, "I don't know, I'm asking you".

She said; "It used to be sugar and water, now it's a bunch of chemicals".

Sugar is mentioned as something that was found to apparently work better than corn starch (at about 8:00 in the above video).

Basically some variation on using bread or toast to make carbon foam.

viewtopic.php?f=1&t=2133&p=12177

I'm thinking some kind of crucible made of carbon foam with a hard fire brick shell. Or some kind of "glue" binder that would be rigid and strong rather than using school glue. Like fire brick clay or Portland cement. Ceramic maybe - porcelain clay.

I bought a real kiln a while back off someone on Facebook marketplace for cooking these sorts of things up, but have yet to get it set up with the 220v wiring somewhere.

[Nobody]

Man it is hard to discuss this on line without making mistakes. I stand corrected, the Vuilleumier heat pump powers it's displacers itself. Work generated from heat input and some exhausted at ambient, obeying Carnot's rule, powers the displacers. At the same time, the result of pressure cycles and timing, heat is pulled from a third colder space. It is intended to be colder because that is the propose of cooling. To cool a space/body colder than ambient.

There is more heat coming out of the hot space, producing work, than cold coming out of the cold space.

There is more heat going into the ambient as waste than coming out of the cold space.

There is no net work going in or coming out, so the heat going in from cold and hot should equal heat going into ambient. Conservation...

If you extract work, you will have less cooling effect. Or a larger device so, more heat in from the hot space, and consequently more heat rejected into the ambient.

Getting cooling for "free", is very efficient. Free is in quotes because it still requires a "free" heat and ambient source, plus the equipment cost, which may be significantly higher than current heat pumps.

[Nobody]

Run the oven/hot-box * at the same temperature as the hot source, so the hot source won't cool off. Perhaps 150 F, or around 50C, 330K would also be fine. Cool enough to be safe, hot enough to make the engine run.

Alternately if running it on ice, put the setup up in the freezer, this will probably just freeze up the engine, so I like the oven better.

* Warning: Oven settings are notorious for being wrong. Use a thermometer to be more accurate. Mine is over a hundred degrees hotter than it's dial setting. 200F would be 300 or more and potentially ruin you engines. Also, insulation burns, be careful, someone may turn your oven up without looking. Thanks.

[Tom Booth]

...
If you extract work, you will have less cooling effect. ...

I don't think that is necessarily true.

In Claude system refrigeration, extracting work INCREASES the cooling effect above and beyond the older Linde cooling method.

By adding work output (an air engine or turbine) to a Linde cooling system, the cooling effect increases. Also the work output from the air engine can be bootstrapped to reduce the load on the compressor

Both the cooling effect and efficiency increase.

This is also true of Stirling engines. They run cooler and more efficiently with a load than in no-load condition.

Granted, the dynamics of the VM heat pump are a bit different than a Stirling, but I would not make that assumption.

[Tom Booth]

Run the oven/hot-box * at the same temperature as the hot source, so the hot source won't cool off. Perhaps 150 F, or around 50C, 330K would also be fine. Cool enough to be safe, hot enough to make the engine run.

Alternately if running it on ice, put the setup up in the freezer, this will probably just freeze up the engine, so I like the oven better.

* Warning: Oven settings are notorious for being wrong. Use a thermometer to be more accurate. Mine is over a hundred degrees hotter than it's dial setting. 200F would be 300 or more and potentially ruin you engines. Also, insulation burns, be careful, someone may turn your oven up without looking. Thanks.

Your instructions make no sense in relation to what Tesla proposed. Nobody, not me, or Tesla ever suggested a Heat engine would run without an initial temperature difference to begin with.

Putting an engine running on hot water in a 212°F oven is just intentionally destroying the temperature difference.

Likewise, putting an engine running on ice in the freezer.

Neither of these experiments would prove or disprove anything other that: a heat engine cannot run without a temperature difference.

What would be meaningful would be to do as you suggested earlier:

If insulation does cut off heat transfer, the zero heat transfered to the cold body should dictate that it will run continuously in an oven. With oven heat supplying the heat, and insulated cold body supplying the cold for your temperature difference

Starlight is one possible insulating material that blocks both conductive and radiant heat very well. Or any kind of carbon foam type material could ba a good candidate to "cut off heat transfer".

[Tom Booth]

This video popped up on my YouTube feed. The continued saga of the search for Starlite.

https://youtu.be/0IbWampaEcM

What I found interesting is the mention towards the end of making a Starlite-like material that works at lower temperature without having to be incinerated in the process utilizing glass micro-balloons.

As it happens...

I do have a theory about haw this stuff could withstand a 10,000 degree heat generating laser, and also cause the laser to malfunction.

I think I read or saw somewhere that these black body heat radiating materials "reflect" heat/infrared light back in the direction it came from.

So a laser directed at the stuff would not only fail to generate the expected heat, the laser beam itself would be reflected back into the machine that generated the laser.

[MikeB]

Close, but not quite - the retro-reflective materials that they use on road signs etc rely on hemi-spheres, not full-spheres - like having a million tiny parabolic satellite dishes. Even then, only about 50% of them point in the right direction, and since they aren't parabolic, those that do reflect aren't 100% efficient either.

[Tom Booth]

Close, but not quite - the retro-reflective materials that they use on road signs etc rely on hemi-spheres, not full-spheres - like having a million tiny parabolic satellite dishes. Even then, only about 50% of them point in the right direction, and since they aren't parabolic, those that do reflect aren't 100% efficient either.

Not sure where road signs came into the picture.

The article I was reading had to do with "black body radiation" or possibly night sky radiation, or possibly some "Starlight" type carbon foaming material.

"Reflection" is not the proper term, absorption and re-emission of heat/infrared is more accurate I think.

That's why I put "reflected" in air quotes. Sorry for the confusion

The company that sent me samples of their various glass and ceramic microspheres does also make stuff for roads and such, but what I have are actual hollow vacuum spheres. But my comment was referring to Starlight - carbon foam, high emissivity type materials.

If possible I will locate the article in my browser history and post a link.

The laser used on the Starlight had a switch or something that tripped it off at 10,000 degrees, and the Starlight tripped the laser off almost immediately or some such thing, but arguably, the Starlight never actually reached 10,000°C as that is 2X hotter than the Sun and even carbon foam could not withstand that kind of heat.

So probably what shut down the laser was "reflected" or re-emission that made it "look like" it was 10,000 degrees.

All that is, of course, speculation.

[Nobody]

Heat radiates omnidirectionally and suffers from the power reduces by the inverse square of the distance law.

[Tom Booth]

Heat radiates omnidirectionally...

Apparently some of these heat radiating (passive cooling) substances/coatings/materials (speaking very generally, as I've been browsing dozens of articles lately), exhibit directionality, either by accident or design, able to beam or send heat to outer space between potential obstacles, like tall buildings.

Something else interesting, I think, is that kept under glass in a vacuum, the cooling effect is increased. Or rather, likely, the fixed amount of radiative cooling is able to accumulate because there is less reheating taking place when protected from the surrounding ambient, resulting in a greater ∆T.

Coincidentally? some of the polymers or whatever being studied are commonly found in hair products. Some are more exotic. Of course nanotech is being used to enhance some of the properties like directionality to make them, (the coatings etc ) "tunable".

My main interest, to begin with was just finding a good insulating material to keep ice cold as long as possible when operating a Stirling engine on ice.

What could be better for keeping something cool than a coating that not only insulates but actually sheds heat?

If an "Ultra LTD" Stirling can run on a ∆T of 3° and under a vacuum, some of these materials can cool as much as 60° I'm not sure why someone couldn't just coat the upper side of an LTD type Stirling engine.

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Image source: https://www.eurekalert.org/news-releases/702190

Raman Lab. - UCLA

Never mind, I forgot. That pesky 2nd law of thermodynamics. Better not try it

It is impossible to convert the heat from a single source into work... - yada yada yada... Something something something.

[Nobody]

Insulating material discussion should be in the Burnt pancake displacer (carbon foam) thread. Or perhaps a new thread on mythical-ideal-perfect insulators and reflectors.

Gold is one of the best reflectors of infrared photons. Carbon black is one of the better absorbers of heat photons/infrared.

NASA uses the principal of shading reflection and deep space blackbody absorption to cool things such as the space station. Perhaps also their Stirling Engine's cold sink. I would.

In the Burnt Pancake thread Tom Booth quoted Tesla:

Tesla scratched his head a little bit and said what if instead of using heat (above ambient), you make a "cold hole". Then you can use the heat of the ambient as it flows in naturally and you will never run out so you don't have to put it back. It is no longer a closed loop. It is a linear system.

Sunshine Hits the earth >>>> Hot Ambient > Heat > Heat converted to Pressure in a Heat engine > Motive Force (work) > Electricity Generation > Eventual heat dissipation into Outer Space >>>>>

A compressed air engine is such linear system. Until you need to recompress the air. A heat engine starting with a hot working fluid, expanding so that it produces maximum work allowing the pressure and temperature to equalize with deep space, will work for one cycle. You will have to either launch it fully assembled and charged into space, or expend a lot of work creating cold evacuated space/sink in a warm atmosphere. That work, will be more than the amount gained back by the maximum single cycle you will get. However, it will work once.

Tesla's concept misses the effects of gravity and the concept of repetition or cycles. It can't be linear if it needs to cycle. All heat engines are cyclic, even if not obvious. Thanks.

[Tom Booth]

In the Burnt Pancake thread Tom Booth quoted Tesla:

That is not a Tesla quote, you've taken a forum post paraphrasing Tesla's idea out of context.

This was my paraphrase: "Tesla scratched his head a little bit and said what if instead of using heat (above ambient), you make a "cold hole". Then you can use the heat of the ambient as it flows in naturally and you will never run out so you don't have to put it back".


"Cold hole" is the only direct quote of Tesla's actual words.

My post was addressing the nonsensical "proof" used over and over again so many times.

Re: Tesla's "Ambient Heat Engine" Experiment
by Nobody » Sat Nov 06, 2021 11:01 am

Insulating material discussion should be in the Burnt pancake displacer (carbon foam) thread. ...
In the Burnt Pancake thread Tom Booth quoted Tesla

:

Your self appointment to forum moderator is just confusing things and muddling up the discussion.

Tesla's concept misses the effects of gravity

Just out of curiosity, how so?

A heat engine starting with a hot working fluid, expanding so that it produces maximum work allowing the pressure and temperature to equalize with deep space, will work for one cycle. You will have to either launch it fully assembled and charged into space, or expend a lot of work creating cold evacuated space/sink in a warm atmosphere. That work, will be more than the amount gained back by the maximum single cycle you will get. However, it will work once.

You have again taken things out of context. Your the only one talking about launching an engine into space. A thermos bottle takes advantage of a vacuum for heat insulation right here on earth. You don't have to go to zero-G.

[Nobody]

Okay. It is not Tesla. Tesla probably knew that it takes as much energy to create a "Cold Hole" as you get back out by filling it. You are the one that thinks it doesn't need to be filled. It takes energy/Work to create a temperature difference when there is none.

You mentioned the cold of space. I was merely trying to point out that the amount of energy to create one here on earth, or if going into space, the amount of energy nessisary to get there.

A thermos bottle contains a working fluid that will need to be heated or cooled. The vacuum, in said bottle, just reduces ambient heating and cooling. If you want to contain another vacuum, mimicking space, you will need to expend more energy to do so. Then the internal temperature will be reflected by the wall temperature. It won't be zero or even close to it as space is. The only way to mimic the cold of space on earth is with liquid helium, or some other similar cooling process.

Think about having two air tanks. A pressure tank and a receiver tank. Pump air into the pressure tank. Use the pressure difference to power an air motor. Once the two tank are equal in pressure the motor stops. To get more work out of the motor the air will be pumped out of one tank and back into the other. Then the motor will run again. This is a cycle.

Air going out of the pressure tank will cool. The pressure tank cools. The receiver tank is warmed, but not as much, by the amount of work the motor extracts and pressure drop. This is in opposition to the work and decreases the total work out. The air, and pressure, must pass through.

Heating the pressure tank, lines, and motor, will give more runtime. Cooling the receiver tank and lines, will also give more runtime. This is a heat engine. It requires heat input and heat output. Heat into the expanding pressure tank. Heat out of the compressing receiver tank. Until the pressures are equal.

Cycling back to the beginning requires the air to be pumped out of the receiver tank and back into the pressure tank. This also would benefit from heat and cooling, but in reverse.

The pressure tank would be cooled and the receiver would be heated. Work input would be required at some point. This is how a Stirling Engine functions, except that the heat needed to reheat the tanks, lines, motor, and air is retained by the mechanics and regenerator. All that is needed, in an ideal Stirling, is to add the heat of expansion, and remove the heat of compression. The latter being the smaller quantity. Real engines mimic that ideal, falling short in many ways.

The Ericsson Engine Cycle is very similar to that description.

I don't have any desire to be a moderator. It was merely a helpful hint. But it's your thread go off topic all you'd like.