Stirlingengineforum.com

Fool wrote: ↑Thu May 16, 2024 10:37 pm ...
I just have one more question, how does ipoo get -32 degrees C out of a chemical that boils at 10 degrees F, in a system that is running at atmospheric pressure?
...

Funny how you believe the video can be easily faked by letting butane evaporate on the outside of the pipe, but can't believe the same thing can happen if the butane is made to evaporate inside the pipe.

Let me ask you fool.

Do you doubt that evaporative cooling (using water) can reduce the temperature of the air? i.e. "swamp cooler".

Why, OMG, how is that possible! Water boils at 212°F !!!!! You couldn't possibly use evaporating water to cool below 100°C !!!!

Evaporative cooling with water works all the way down to near the freezing point of water.

Butane freezes at -216.4°F or -138°C

Does that tell you anything?

Actually, no, it doesn't. Evaporative cooling requires mass removal. Evaporative cooling requires air flow to carry the water away. The mass carries away the heat. Neither are happening inside that system.

The vapour compression cycle requires a pressure difference between boiling, and condensation. Boiling at a lower temperature and pressure, and condensation at a higher temperature and pressure. Hence an orifice and pump.

So how much pressure difference does there need to be to get a temperature swing between room temperature and -32 °C, something like a ∆T of 50 °C ? Is that tiny little compressed capable of that much pressure difference? Can the tiny little 9 V battery provide that much wattage and watt hours?

Here I thought the question was straight forward, instead you are way off in swamp cooler land, far far away from vapour compression cycles. Evaporation is different from boiling.

Pause the video at 8:05 and inspect the coils. The smaller tube is completely frosted up. Weird.

The larger coil has hot and cold spots signifying uneven cooling. How is that accomplished on a heat conductive copper pipe with claimed even cooling happening inside.

It's a fake.

Why was the video stopped and started several times while allegedly cooling? Magic trickery. It is so obvious. Sorry you missed it.

Short piece of not sufficiently small enough tube to create any pressure difference with a low flow low pressure pump. No attempt at a valid sized orifice. Sorry you missed it.

Frost that appears at the edge of melting, while being claimed at -32 °C. Sorry you missed it.

Good luck with your constructions. If you succeed I'll apologize. Please let us know.

Again, you don't know what your talking about I'm not going to waste any more time trying to educate someone who first can't recognize a simple "orifice" watches half a dozen videos, still claims "no orifice".

When proven wrong doubles and triples down, making additional claims about the inadequacy of the "orifice" he claimed didn't exist, was never installed.

You dance this same dance over and over in every topic, wasting mine and everyone else's time, but of course, if I just ignore you you'll gloat that you are right.

I don't care. Enjoy your moment of glory.

Maybe something could be done with one of these little tire inflator compressors.

They actually contain a little thimble size, mechanically driven air compressor I'm pretty sure could be driven by a small LTD Stirling. Not to 300 psi obviously but it could move some air.

https://youtu.be/3I_dvrHJfG0

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According to Tesla's theory; if we had something like this setup:
If we first ran the Peltier module to cool the bottom plate. (Keeping it insulated of course, to preserve the cold).

The engine could then run on the surrounding ambient heat, and with perfect insulation and a 100% efficient engine, it could run indefinitely.

He recognized however, that with the technology current in his day, those two conditions could not be met, so the "cold hole" would need to be re-cooled or refrigerated from time to time.

But, be reasoned. Because the engine is actively converting the ambient heat entering into the engine to other forms of energy, less heat would reach the sink than goes in at the top.

He further reasoned, that when heat did need to be removed from the "cold hole", it could be taken out "by its own energy".

To explain, let's say, (as illustrated above), we have a heat pipe that takes the heat generated by the Peltier unit while operating and carries that heat back up to the ambient side on top.

In this way, the heat taken out of the "cold hole" will assist in its own removal.

While heat is being removed, the temperature difference will increase and the engine will have more power to make the cold hole colder using the heat taken out of the cold hole.

After that, the engine can run steadily on the ambient heat once again.

He believed this scheme did not require a 100% efficient engine.

Occasionally I do a search for the availability of any kind of small turbine, in particular Tesla turbine.

There is this 3" diameter one finally appearing through several sellers on eBay, just in case anyone else is interested.
I'm not providing a link to any particular seller. There seems to be half a dozen or more selling this exact same turbine.

This is also not a recommendation. I have no idea about quality or anything else other than what can be seen as advertised on eBay.

Anyway, I'm sending for one, as I need one for experimenting and this is the first one I've ever seen, easily available. Or, available at all, since I started looking, years ago.

Oh, BTW, while we are on the subject of the "orifice" in a refrigeration system...

There are of course several types.

A refrigeration or heat pump system consists of two basic components.

1) a compressor or pump of some sort.
2) a tube or pipe connecting the pump outlet with the pump inlet.

The pump simply circulates a fluid round and round and round in a loop.

And one more thing. Some kind of "kink" in the pipe somewhere.

The kink or restriction (or "orifice") in the circuit causes pressure to build up on the pumps outlet side of the pipe and a partial vacuum to develop on the pump (or compressor) inlet side.

The restriction still lets some gas or fluid through, slowly, but holds it back enough so that 1/2 the loop builds up pressure and heat.

The heat that builds up is blown away with a fan.

Now, when the gas or fluid finally makes its way through the restriction it expands into this partial vacuum side and cools down. Because it is now very cold it can absorb heat, making ice cubes and such.

From there it gets sucked back into the compressor and the process starts all over again.

Usually this process involves phase transition. But in an "air cycle" refrigeration system there is no phase transition. The gas is simply pumped around and around and around in a loop without undergoing any phase change. But something else is required. A different kind of "orifice" or restriction.

Instead of an orifice, an air-cycle system uses a turbine. (Usually, or expansion engine)

The refrigeration in this case is not just from the gas or fluid doing work expanding through an orifice against itself, (Joule -Thomson) but by doing work driving the turbine.

For this to work, however, as the gas pases through this turbine "orifice" or restriction in the line, the turbine needs to actually do some kind of work or other.

In most cases, the most convenient and immediate work available to be done in such a system is to help drive the compressor.

So, the compressor compresses the air and the turbine acts as a metering device, valve or "orifice" that hold the air back so it heats up, then allows the compressed air to expand again, and the turbine helps drive the compressor taking energy out of the gas so it loses internal energy and cools.

The turbine can also be used to drive the cooling fan, to help cool the gas down before it expands.

Of course, the gas has been cooled before it drives the turbine, so has less energy, so the turbine can't do ALL the work of compressing and cooling the gas that drives it, so some kind of drive mechanism is still needed, but to some degree, the work of compressing the gas in an air-cycle system is gotten back during expansion.

In other words, in a cryogenic air cycle refrigeration system the "orifice" or metering device is actually a turbine rather than just a pinhole or a valve.

Of course, instead of a turbine, a reciprocating engine could be used, but obviously a turbine is more efficient.

And maximum efficiency can be identified by the temperature difference between hot and ambient. And cold and ambient. Depending on work and heat travel directions. Real engines will be worse.

Glad to be back on the subject of this thread, "Tesla's ambient heat, generated cold hole, perpetual motion, over unity, machine, with more cooling from work than heating from reverse work." What an improvement. Please build one. People have faith in you. It's only the Fool that doesn't.

Fool wrote: ↑Sat May 18, 2024 5:59 am .... Please build one. People have faith in you...

I don't think anyone needs "faith" to build an air-cycle refrigerator.


https://youtu.be/OXIZhqypNUI

True. It won't even help if you get just faith. Money maybe. But building a perpetual motion machine, probably nothing will help. But I want one, so please build one.

"He further reasoned, that when heat did need to be removed from the "cold hole", it could be taken out "by its own energy"."

No. Heat only transfers from a hotter to the colder temperature. Heat isn't energy, it's the flow or transfer of energy. Since calorics were discarded, heat became nothing.

Internal energy can be converted to work/kinetic energy, momentum. That momentum can in return be used to reduce internal energy more. The difference you speak of is whether the momentum is discarded or used for additional cooling. Both are adiabatic expansion with work. One might be more efficient than the other, a good thing, but the overall efficiency will not beat the Carnot prediction.

A refrigeration cycle requires more work input to the gas during compression.

Heat removal by a lower temperature sink.

Followed but expansion temperature drop, less work out, and potentially followed by work back in and further temperature drop.

This cold temperature must then be put into contact with the mass being cooled. The working gas can't be released to the atmosphere because it will be at a lower pressure. Air would just rush in warming it up. This is why Stirling Engine cryo coolers are seal units, and conduct their cooling through the heat exchanger to the outside air.

Please give us your theoretical PV diagram for your alleged Tesla ambient process.

P.S., The Tesla turbine might be a very good device to use as you are planning. It is very robust in hazardous mediums, such as potential icing. They seem to work well for pumping. Your application won't care so much about efficiency because you are going more for, cooling, longevity, toughness, and low maintenance. All those are good for the Tesla turbine. Good luck Cary on. Please let us know.

Of course you could just use a Stirling cryo cooler to make your cold hole. They are supposed to be very efficient.

Fool wrote: ↑Sat May 18, 2024 9:09 am ...
"He further reasoned, that when heat did need to be removed from the "cold hole", it could be taken out "by its own energy"."

No. Heat only transfers from a hotter to the colder temperature. ...

Obviously, as usual, you don't even understand the proposal or the basic principle involved.

Who can make any sense of your incoherent rambling?

The point is, if you know how a refrigerator or heat pump works, to produce air conditioning or refrigeration, to produce the cold desired, a great deal of relatively high grade heat is generated and thrown away.

If you could use that "waste heat" to run a heat engine the power generated by the heat engine could take some of the load off the cooling systems compressor.

In this way, at least some of the heat would be removed; "by its own energy".

What is not converted in flowing down can just be raised up with its own energy,

https://teslauniverse.com/nikola-tesla/ ... man-energy

Just putting Tesla's statement in perspective.

Tom Booth wrote: ↑Fri May 17, 2024 3:39 am Let me ask you fool.

Do you doubt that evaporative cooling (using water) can reduce the temperature of the air? i.e. "swamp cooler".

Why, OMG, how is that possible! Water boils at 212°F !!!!! You couldn't possibly use evaporating water to cool below 100°C !!!!

Evaporative cooling with water works all the way down to near the freezing point of water.

Butane freezes at -216.4°F or -138°C

Does that tell you anything?

Tom - you obviously don't know how swamp coolers work. Many decades ago, I lived in Phoenix for a couple years when everyone had these, but they're worthless there today (there's a clue in there). So yeah, I know how they work and not from bad internet buzz.

And you do raise an amusing question...just how does water evaporate when the water temp is the same as air temp, like a standing bowl of 20C water sitting on a table in 20C room.

matt brown wrote: ↑Sat May 18, 2024 3:42 pm

Tom Booth wrote: ↑Fri May 17, 2024 3:39 am Let me ask you fool.

Do you doubt that evaporative cooling (using water) can reduce the temperature of the air? i.e. "swamp cooler".

Why, OMG, how is that possible! Water boils at 212°F !!!!! You couldn't possibly use evaporating water to cool below 100°C !!!!

Evaporative cooling with water works all the way down to near the freezing point of water.

Butane freezes at -216.4°F or -138°C

Does that tell you anything?

Tom - you obviously don't know how swamp coolers work. ...

Really?

And why do you say that Matt Brown?

I know exactly how swamp coolers work.