Tesla's Heat Engine

Discussion on Stirling or "hot air" engines (all types)
Tom Booth
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Tesla's Heat Engine

Post by Tom Booth » Sun Jun 19, 2016 1:49 am

As some here may be aware I've previously posted about the possibility of a heat engine running on ambient heat. Tesla worked on building such an engine and I think somewhere in a letter claimed to have done so. At any rate he wrote about the possibility.

Recently I purchased a mini metal lathe and some other machinery. I intend building such an engine based on the theory Tesla outlined in an article.

It is a bit complicated. More or less a marriage between a Stirling Engine, a compressor, refrigerator/heat pump and an air liquefaction machine combined.

As far as is known Tesla did not leave any working model, detailed drawings or anything else to go on. Some writers on the subject suggest he was talking about some kind of universal ether or cosmic energy having nothing to do with heat or heat engines. He speaks in terms of general principles, so I suppose there is room for some confusion but his explanation seems perfectly clear to me.

Such an engine was in Tesla's day considered an impossibility and is generally so considered today; a violation of the Second Law of Thermodynamics. Tesla didn't like the word impossible and set out to find a workaround. He thought of several possibilities but considered the modified heat engine the Ideal which could in fact be practically implemented as a source of motive power.

Tom Booth
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Re: Tesla's Heat Engine

Post by Tom Booth » Mon Jun 20, 2016 1:25 am

After studying all the elements that went into cycling ambient air through this machine and putting it all together in a way that made sense to me, based on basic principles, I imagine the air being cycled this way:

Ambient air is drawn in by means of some form of air pump/compressor. The air taken In is pumped into a long tube. The compression of the air in the tube raises the temperature of the air in the tube and the tube itself which curls around the hot end of a Stirling engine. From there the compressed air is released through a pneumatic device. Say an air motor which is attached to the Stirling Engine crankshaft. In this way not only the heat of compression is utilized by the Stirling but also the Stirling is further assisted by the air motor. Heat remaining in the pipe not utilized by the engine can be reclaimed and recycled by having the pipe pass through the incoming air stream. This also assists with cooling the compressed air as it leaved the hot side of the engine and then enters the air motor. The air might be further cooled by passing it (the pipe) through a water bath. In theory all this should take much energy out of the air causing it to drop in temperature. Ideally far below ambient temperature. Yet it is still contained in the pipe which now quite cold continues on around the cold end of the engine. Any remaining Cold not at once utilized by the engine can be used to pre-chill the cold pipe further as with the "self cooling method" used in Lind air liquefaction.

So what runs the compressor that supplies all this hot air? The Stirling Engine of course.

Maybe this sounds as dumb as the idea of using an electric motor to run a generator which runs the motor that runs the generator But it isn't quite the same thing IMO. Tesla was not that dumb. He was looking for a MAXWELL'S DEMON.

DLantz
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Re: Tesla's Heat Engine

Post by DLantz » Mon Jun 20, 2016 5:09 am

My first instinct is in line with yours. That we are discussing an impossible perpetual motion machine. But it sparks some ideas. Like possibly using seasonal temperature swings to power this device using liquified air. Like on the coldest nights of the winter, we liquify air using stored thermal energy from the summer months and then store that 'coolth' in an insulated underground tank.

My thought is that liquified air would be a really dense storage method for 'coolth'.

DLantz
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Re: Tesla's Heat Engine

Post by DLantz » Mon Jun 20, 2016 5:12 am

I had a notebook here somewhere that I sketched out a seasonal storage method using phase change materials of different temperatures, coupled with a heat driven chemical heat pump (calcium chloride type). The thought of it was to boost the storage and utilization of the warmth and 'coolth' by using the heat pump. I don't see why the stirling engine concept couldn't be used for it.

Tom Booth
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Re: Tesla's Heat Engine

Post by Tom Booth » Mon Jun 20, 2016 8:41 am

Have you ever heard of Charles Tripler ? He had, back in 1890 come up with a way to make liquid air by the barrel full and found that he could use the liquid air to run a steam engine to drive an air compressor to make more liquid air. He was able to use 3 gallons of liquid air in his machine to make 10 more gallons.

There was much excitement about it at the time... until scientists started screaming "impossible" and he was accused of fraud. Investors got scared off and a business associate ran off with the money and Tripler died in disgrace. His method for producing "free energy" / perpetual motion was roundly dismissed as a hoax and forgotten.

It makes an interesting case study from an historical perspective.

I believe Tripler was, in fact entirely honest and his claims or reported observations were straightforward and entirely accurate.

Tesla's proposed stand alone engine follows or utilizes the same basic principles demonstrated by Tripler's "perpetual motion" air liquefaction process. Though cooling the air to the point of state change for long term storage would not be necessary in a stand alone engine.

DLantz
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Re: Tesla's Heat Engine

Post by DLantz » Mon Jun 20, 2016 11:44 am

Hmmm... I wouldn't believe anything I couldn't get my own hands on.

That said, I've been following something called "photonic radiant cooling" which has applications in air conditioning. It is a method of making a surface 'see' space by matching the frequency of the atmosphere or some such physics black magic I fail to understand.

But the articles were peer reviewed and the effect duplicated. What it did was to create a surface that was 10-20 degrees colder than the surroundings, even in full sun, which it reflected the infrared.

My question would be, could you take this magic surface and isolate it thermally from ambient with something like the borosilicate, vacuum solar tubes. In theory, you could slowly liquefy air allowing it to give up all its heat to outer space.

Does that make sense to anybody else?

To keep it relevant to heat engines, you could also possibly run a stirling off that temperature difference.

Tom Booth
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Re: Tesla's Heat Engine

Post by Tom Booth » Mon Jun 20, 2016 3:11 pm

The photonic radiant cooling is, to say the leas, interesting. If this material is 9 degrees cooler than ambient air by virtue of just sitting there radiating heat into space one would think it could be put on the top of one of those "ultra LTD" Stirling engines and have it running with no further ado.

Tom Booth
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Re: Tesla's Heat Engine

Post by Tom Booth » Mon Jun 20, 2016 7:17 pm

DLantz wrote:Hmmm... I wouldn't believe anything I couldn't get my own hands on.

That said, I've been following something called "photonic radiant cooling" which has applications in air conditioning. It is a method of making a surface 'see' space by matching the frequency of the atmosphere or some such physics black magic I fail to understand.

But the articles were peer reviewed and the effect duplicated. What it did was to create a surface that was 10-20 degrees colder than the surroundings, even in full sun, which it reflected the infrared.

My question would be, could you take this magic surface and isolate it thermally from ambient with something like the borosilicate, vacuum solar tubes. In theory, you could slowly liquefy air allowing it to give up all its heat to outer space.

Does that make sense to anybody else?

To keep it relevant to heat engines, you could also possibly run a stirling off that temperature difference.
It makes sense assuming this nano film or wharever it is gets colder than its surroundings. Which if thermally isolated would make the surroundings that much colder over time ... Then it would again get "colder than the surroundings" presumably all the way down to absolute zero. If some of the claims about it are taken literally.

Will it ever see the light of day?

Tom Booth
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Re: Tesla's Heat Engine

Post by Tom Booth » Tue Jun 21, 2016 12:50 am

Ordinary glass I don't think will transmit infrared light. It is possible to get such glass. The articles about it say that it needs to have "direct exposure to the sky.

Apparently it would not work inside a building but only on the roof. Putting it inside anything to thermally isolate it could be problematic .

DLantz
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Re: Tesla's Heat Engine

Post by DLantz » Tue Jun 21, 2016 3:30 am

Tom Booth wrote:Ordinary glass I don't think will transmit infrared light. It is possible to get such glass. The articles about it say that it needs to have "direct exposure to the sky.

Apparently it would not work inside a building but only on the roof. Putting it inside anything to thermally isolate it could be problematic .
I looked into glass and IR transmission many years ago, so my memory is fuzzy on it. If I remember correctly, it mattered what type of glass and also, what the frequency was. Higher frequency IR can get through a lot, lower gets trapped. That is the basis of the CO2 greenhouse effect, if I understand it correctly.

I would wonder, if this material allows transmittance of IR back through our atmosphere by its magic surface properties, would it also allow transmittance through glass, or some type of glass? Could we tweak the surface to do so? Interesting stuff.

Ian S C
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Re: Tesla's Heat Engine

Post by Ian S C » Thu Jun 23, 2016 3:56 am

I know that there is a difference between ordinary window glass, and the agricultural glass used in glass houses/ green houses, the ag glass allows the passage of IR, and UV light, I think it is due to removal of metals such as lead in the glass.
Ian S C

masaruneema
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Re: Tesla's Heat Engine

Post by masaruneema » Thu Jun 30, 2016 9:45 pm

Putting it inside anything to thermally isolate it could be problematic .
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Wellington
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Re: Tesla's Heat Engine

Post by Wellington » Mon Aug 15, 2016 1:03 pm

Tom Booth wrote:As some here may be aware I've previously posted about the possibility of a heat engine running on ambient heat. Tesla worked on building such an engine .

Take a look at Robert murray smiths video on youtube about a stirling angine with no moving parts. might be of interest to you.

regards

Wellington

Wellington
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Re: Tesla's Heat Engine

Post by Wellington » Mon Aug 15, 2016 1:05 pm

Tom Booth wrote:As some here may be aware I've previously posted about the possibility of a heat engine running on ambient heat. Tesla worked on building such an engine........ .

Take a look at Robert murray smiths video on youtube about a solid state stirling engine. might be of interest to you.


regards

Wellington

Ian S C
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Re: Tesla's Heat Engine

Post by Ian S C » Tue Aug 16, 2016 2:25 am

I think most of us have built a Stirling Engine with "no moving parts", it wasn't supposed to be that way, it just would not go. LOL
Ian S C

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