Tesla's "Ambient Heat Engine" Experiment

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

Postby Tom Booth » Sun Aug 20, 2017 9:43 pm

Ian S C wrote:Tom I have run my LTD motor on ice, the ambient temperature was 20*C, so there was a 20* (a little less) temperature differential. The but is the amount of energy required to make the ice.


You certainly make a valid point. Energy is required to make ice in the first place of course. As quoted above, Tesla's reasoning was:

"We would thus produce, by expending initially a certain amount of work to create a sink for the heat to flow in, a condition enabling us to get any amount of energy without further effort."


In otherwords, Yes it requires energy to make ice and ice is needed to get the engine started, but once started, the engine is then being powered by, not the ice, but the surrounding ambient heat.

A "Real" Stirling Engine has a regenerator, which apparently can be very efficient at preventing heat loss to the sink (the ice).

Most people, I mean YouTube videos I've seen, make no effort to insulate the ice from the surrounding ambient heat to prevent it from melting. I'm wondering what would be the result if the LTD Stirling (Preferably with a regenerator) were placed on top of a dewar type thermos full of ice. (As illustrated in the above experiment).

Ideally the engine should be running some kind of generator so as to be converting the ambient heat energy into some other form of energy, - electricity or mechanical output ("work").

Could that energy output then be used to actively remove heat from the ice as necessary so as to keep it cold and prevent it from melting and so allow the engine to keep running on the supplied ambient heat, which is really indirect solar energy.

Tom Booth
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Joined: Tue Nov 07, 2006 2:03 am
Location: Fort Plain New York USA
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Re: Tesla's "Ambient Heat Engine" Experiment

Postby Tom Booth » Sun Aug 20, 2017 10:00 pm

Removing heat from the ice is really not a correct statement. If you study how a heat pump or refrigerating system actually works, it is more like the heat is removed during compression of the gas refrigerant. In those days refrigeration was accomplished by compressing air. The old "Cold Air Machines" worked by compressing air and removing the heat from the air during compression (which also made compressing the air easier. If heat is removed DURING compression of the air the air tends to contract naturally as it is cooled).

The relatively cool compressed air, having had the heat removed from it is then allowed to expand. This air is then extremely cold. Much colder 6than what would be needed to make ice. Air compressed cooled and expanded in such a way, especially if made to do work as it expands, can reach cryogenic temperatures.

If heat were water, then this cold air is like a dry sponge to soak up heat from the ice.

If you are continually squeezing heat out of the air to get the heat energy to run the Stirling engine then returning the cold "Dry" air back to the atmosphere to absorb more heat, then you only need to allow this cold air to kind of "mop up" any excess heat on its way back to the outside atmosphere.

I would say that the 2nd law of thermodynamics does not apply as this is an "OPEN SYSTEM" and it is not "Perpetual Motion" it is just an indirect use of solar energy.


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