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Nikola Tesla Vs. The Second Law Of Thermodynamics


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Posted Today, 09:52 AM

TomBooth, on 15 Aug 2020 - 1:11 PM, said:snapback.png

If boiling water is being applied at 212F and 80% of that is going straight to the sink, then it seems to me the sink should be closer to 212 than to ambient, which was 85 F at the time.

 

Not if it is efficiently dissipating the heat to the greater ambient surroundings. If the sink gets as hot as the source, the machine will not work. Hopefully with that thermometer you now have, you can take some T data and clear up some of these questions.

 

 

Yes, though I don't have the thermometer yet. Mail order is agonizingly slow these days. I really appreciate your input. It is very encouraging.

 

"If the sink gets as hot as the source, the machine will not work", That is absolutely true, as far as anyone who has ever worked with these engines, model builders and such, has ever known. The idea that insulating the heat outlet or "sink" was so "Out there" and completely contrary to what "everybody knows" I didn't bother with the time and expense to test it, for Ten Years. Why bother? Obviously insulating the sink would cause the heat to build up and the engine to slow down and stop, but I kept noticing strange things about these engines that told me something was wrong with the prevailing view.

 

Like this video, which I've posted, probably a dozen times:

 

https://youtu.be/DyPxNNJQo9M

 

Now compare that with what "everybody knows": "The engine will not run without a flywheel period. The flywheel gives the engine the inertia to rotate the crankshaft when there is no combustion in any of the cylinders."...   https://www.3geez.com/forum/3geez-accords/39958-rear-main-oil-seal.html#post473847

 

That is something I was taught in trade school engine repair class back in high school. You can't get 100% combustion, there is always some left over heat in the cylinder, so the flywheel is absolutely necessary to carry the engine through a complete cycle.

 

But this guy discovers BY ACCIDENT, that his model Stirling engine can run without a flywheel. So what brings the piston back?

 

My conclusion is that, in SOME Stirling engines, at least, the gas in the engine is cooling enough that the piston is able to completely return without any assistance from a flywheel, presumably due to adiabatic expansion (converting heat into work).

 

 

 

 

 

Quote

The flywheel in on top of a plexiglass pedestal. Plexiglass is an extremely poor conductor of heat.

 

 

Sorry, I should have noticed the plexiglass pedestal, but somehow missed it. It would help to have the device sitting in front of me.

 

 

On another forum, I offered to have the kits mailed to them if someone would repeat the experiments. (Instead I was banned). The offer generally holds though.
 
 

Quote

The drive shaft?
 
OK, well, that is connected to the graphite piston. How good of a heat conductor is graphite? I think the idea that all that "waste heat" is traveling through the piston and up the connecting rod to the flywheel is a stretch of the imagination, but I can construct a wooden or plexiglass connecting rod, (I think) to rule that out.

 

 

Yes, it is a stretch but I have seen some odd things in my time as a marine engineer. It would be useful to eliminate that as a possibility if it can be done without completely re-designing the machine. I was thinking maybe a heat insulator could be inserted somewhere between where the linkage connects to the flywheel. It may not be necessary to change the piston or the connecting rod.

 

All I can do is throw out some ideas and it is difficult to be specific without having the engine sitting right in front of me. Then again, it is a lot easier to sit here and say "try this and try that" than it is to actually do the work! :whip-new:

 

 

 

Again, your thoughts on the subject are very much appreciated. More than you know. I've seen some odd things as well.

 

I have a question for you. I noticed you gave the flywheel a spin to get the engine started. Is that always necessary, or will it get going by itself if you just wait long enough? Does it behave the same with and without the insulation you installed?

 

 

Yes, almost all Stirling engines need an initial manual boost to get them "kick started". But that is true of internal combustion engines as well.

 

Very rarely, if the piston is positioned just right, and heat is applied, the initial expansion might be enough to get the engine going.

 

I've seen a few posts of people who said they had an engine that was reliably "self starting", but that is not common.

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Carnot efficiency is the maximum theoretical efficiency of a heat engine operating between ANY two temperatures.  That would be for a "perfect" engine without any loses to friction, heat leakage,bad s

I ordered this digital thermometer a few days ago. It comes with four probes for taking simultaneous readings. It doesn't record data to the cloud or have software to build charts and plug into the co

I said "If", hypothetically.   Just supposing that the engine could utilize that additional 7 joules otherwise rejected to the sink. That would only bring the temperature back down to equilibrium with

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Posted (edited)

BTW, I'm working on making that epoxy piston:

 

Update: The epoxy has set, but I failed to get out all the air pockets.

 

I may try to make it work anyway, while another one is setting.

 

Epoxy may not work very well after all, some forum posts on the subject say it has problems similar to Teflon or other plastics. Too much drag.

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Edited by TomBooth
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This is probably nothing, and not really worth reporting, but It seems rather strange to me.

 

Over the years, several times in various forums on this topic, I posted this video, because it looks like, when the engine is picked up, that it is frozen to the ice.

 

https://youtu.be/L6Jmdve1JK8

 

I speculated, that, because that engine comes as a kit, there are a lot of ways to put it together. I had one or these engines (before I destroyed it, experimenting with it) and the piston pushes onto the connecting rod and is retained by a retaining clip by pressure.

 

There is a lot of leeway in terms of how far the piston is pushed on. How far it is pushed on changes the throw of the engine, which I theorized, could easily alter the amount of or degree of adiabatic expansion. i.e. cooling.

 

So, maybe this guy got lucky and happened to push the piston on, just the right amount, to turn his engine into a refrigerator of sorts, or a Stirling cooler/engine purely by accident.

 

Very unlikely, but it really looked to me like that engine was frozen on, not just hanging on by adhesion from moisture, though that was a possibility, it just didn't look that way to me. The heavy block of ice probably would have slid to the side and fallen off.

 

Anyway, I shaped and drilled and tapped the epoxy piston this evening.

 

It did have a lot of drag, friction. It isn't graphite, so I tried adding some 3 in 1 oil. That worked well enough to get it running.

 

First I ran it on hot water for a while, but the engine was laboring pretty hard, due to the extra drag.

 

I decided to try running it on ice for a while. I had a couple of vacuum flasks with ice in the freezer, so took one out, figuring I'd just leave the engine running for a few hours to break in the piston. The last time I ran one of these engines on ice it ran for 33 hours. That should be enough to break in the new piston, and I won't have to babysit the thing.

 

I had dinner, while the engine was running. Just a bit of lasagna.

 

After that I went to check on the engine, but it wouldn't lift off the ice.

 

When I first put the warm engine on the ice, it was still warm from running on hot water and was sliding all over the place on the wet ice, which partly melted from the heat. (This can be seen in the other video in the begining also, he keeps repositioning the engine and it keeps sliding to the side).

 

Well, as the engine was running during dinner, the ice had refrozen to the bottom of the engine. It was really frozen solid, not adhering due to suction from the moisture or anything like that. It was definitely frozen.

 

I was finally able to break the engine loose, but it was not easy, and I could see that the bottom was frosty looking, not wet at all, and the ice was still solid. Not melted on top, like it had been before.

 

I put the engine back on the ice.

 

About five minutes later, I checked again and it was frozen to the ice again.

 

The third time I went to check a few minutes later, I wanted to have a recording of what I found. So I let the engine run a few more minutes to give it time to refreeze again, then made a video.

 

After uploading the video and writing a discription and everything, Before posting the video, I checked the engine again. It was frozen to the ice again.

 

I left it to run, to see what happens. As I write this it is still running, but very very slowly. About 25 RPM.

 

Probably the ice was just very very thoroughly cold from being in the freezer for a long time, but This did not happen before. At least I didn't notice it, and I've already done several experiments running engines on ice.

 

I'm still surprised the ice could refreeze that many times, in particular, if the engine is supposed to be pushing heat through into it, as the "sink".

 

I'm wondering, because the engine is laboring harder than normal with the drag from the new piston, and the epoxy transmits so much less heat than the graphite, maybe it's converting more heat into work??

 

I hope that thermometer arrives soon.

 

It is about midnight, so I'm turning in. I'll be curious to see what develops by morning, if the engine is still running.

 

I counted 26 RPM on the kitchen timmer (digital on the microwave) this time.

 

It is hard to believe the engine can run so slow. Less than one revolution every two seconds.

 

Anyway, looks like the epoxy piston is a success.

 

The engine is running anyway.

 

 

One thing I can say is that I don't think I have ever in my entire lifetime seen any ice refreeze by itself once it had started to melt.

 

Of course, I don't normally keep ice in a vacuum insulated cup in the freezer either.

 

BTW, is there some way to embed videos? I can't figure out how to do that here, but I see videos embedded on other threads, so I guess it is possible, or is it one or those things you have to be a forum member for X amount of time or something?

 

PS. I woke up to a knock on the door early this morning. That was really fast.

 

It was FedEx with my new thermometer! But I have to go out and get a 9v battery.

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Edited by TomBooth
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Interesting, but I’m not sure what to make of all of this.

 

You have made good progress with the epoxy piston and now that you have the thermometer, you can get some good T data.

 

I am going to go out on a limb and hazard a guess that the engine runs so much slowly because the epoxy piston, along with the insulation on the top plate, is reducing the amount of heat that can be transferred from the hot source to the cold sink, which is what the experiment was intended to show.

 

I did some back of the envelope calculations and will post them later, but very roughly, if one cup of water at 373 K cools down to ambient 300 K, it releases about 72,500 Joules of heat energy.

 

If it does that in 30 hours, that is only 0.7 Watts of continuous power. At 20% efficiency, the work done to spin the engine is only 0.14 Watts continuous. So, the heat dissipated by the ambient sink is only a little more than half a Watt, continuous power. It is no wonder you felt the top plate as being ambient!

 

Now, with the insulation, that tiny amount of heat was probably being dissipated by the piston, linkage and flywheel. With the epoxy piston, it would seem to have nowhere to go, but I assure you the heat will find some path out, but it will not be an efficient path. I would guess that is why your engine is freezing up. I would like to see how it runs on hot water, if you don’t mind.

 

If I am right, it will not run very well. Next, if you remove the insulation and it starts running better, you will know it is not piston drag that was slowing it down but lack of heat transfer.

 

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TomBooth; thank you for posting this interesting topic, very brave of you to challenge both the second law of thermodynamics heat flow statement: ‘Heat flows spontaneously from a substance at a higher temperature to a substance at a lower temperature and does not flow spontaneously in the reverse direction’ and also Carnot’s principle, (An alternative statement of the second law of thermodynamics), ‘No irreversible engine operating between two reservoirs at constant temperatures can have a greater efficiency than a reversible engine operating between the same temperatures. Furthermore, all reversible engines operating between the same temperatures have the same efficiency’.

I believe heat engines could have been used on submarines. It would be surprising if the second law or Carnot’s principle were wrong, but I like the saying: ‘question everything you think doesn’t add up’.

 

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TomBooth; thank you for posting this interesting topic, very brave of you to challenge both the second law of thermodynamics heat flow statement: ‘Heat flows spontaneously from a substance at a higher temperature to a substance at a lower temperature and does not flow spontaneously in the reverse direction’ and also Carnot’s principle, (An alternative statement of the second law of thermodynamics), ‘No irreversible engine operating between two reservoirs at constant temperatures can have a greater efficiency than a reversible engine operating between the same temperatures. Furthermore, all reversible engines operating between the same temperatures have the same efficiency’.

I believe heat engines could have been used on submarines. It would be surprising if the second law or Carnot’s principle were wrong, but I like the saying: ‘question everything you think doesn’t add up’.

 

 

In fact, Stirling engines are being used on Sweden's submarines and there are plans for other nations to follow suit.

The main advantage is stealth of operation. Since there are no internal "explosions" as in internal combustion engines, the  "Stirling Hot Air Engine" runs very quietly.

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In fact, Stirling engines are being used on Sweden's submarines and there are plans for other nations to follow suit.

The main advantage is stealth of operation. Since there are no internal "explosions" as in internal combustion engines, the  "Stirling Hot Air Engine" runs very quietly.

 And who do they plan to attack?? 

You're not building a nuke sub for shits and giggles. 

 

I'm deviating off a great discourse, but you build something for use, right?? 

Edited by Racoon
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Posted (edited)
I am going to go out on a limb and hazard a guess that the engine runs so much slowly because the epoxy piston, along with the insulation on the top plate, is reducing the amount of heat that can be transferred from the hot source to the cold sink, which is what the experiment was intended to show.

 

With the epoxy piston, I wasn't really doing an experiment yet. My only real intention was to see if the piston worked at all. It didn't, until I gave it a little oil. Just feeling the epoxy piston between the fingers, it had that grabby feel, like plastic "cling wrap". very different than the silky slick feel of the graphite. Also, in testing the engine on hot water, I did not use any insulation whatsoever.

 

When I switched to running it on ice, I wasn't using any insulation to start with, but I couldn't keep the engine on top of the cup of ice, it kept sliding off.

 

Finally, I put the cup of ice and the engine in the cradle of insulation I had left over from a previous experiment, just so that the insulation would hold the engine in place as the ice, which was beginning to melt on the surface was too slippery. I did not insulate the top or the sides thoroughly, as I was not intending to do any experimenting, just run the engine to break in the piston so that maybe it would smooth out or something and eventually run better without so much drag. That did not really work.

 

Certainly I do think the epoxy conducted less heat than the graphite, but the epoxy was really creating a lot of drag on the aluminum cylinder. I think I may need to try and make a glass piston, as after getting "broken in" last night, the epoxy piston really does not seem to be working today hardly at all.

 

I did some back of the envelope calculations and will post them later, but very roughly, if one cup of water at 373 K cools down to ambient 300 K, it releases about 72,500 Joules of heat energy.

 

If it does that in 30 hours, that is only 0.7 Watts of continuous power. At 20% efficiency, the work done to spin the engine is only 0.14 Watts continuous. So, the heat dissipated by the ambient sink is only a little more than half a Watt, continuous power. It is no wonder you felt the top plate as being ambient!

 

 

There is a bit of confusion here.

 

The engine ran for 33 hours ON ICE (or ambient heat, but ice as the "sink").

 

On a cup of boiling hot water, I have never been able to keep the engine running more than a few hours, with or without insulation.


On hot water, without insulation, the engine ran for about 2 hours and 20 minutes. With the top (sink) insulated the engine ran at a higher RPM but not much longer, barely more than three hours. However, at that time I was not measuring the water precisely, just pouring it from the kettle into the cup, about half full, so I really need to do those experiments over.

 

But, for your calculations above, on 1 cup of boiling hot water, (the large vacuum insulated mugs I used hold about 2 cups so half full is probably approximately 1 cup), the time factor should be reduced from 30 to 3, or more likely 2 1/2 hours.

 

Either way, I don't think a little toy engine is producing much power, but just FYI.

 

Now, with the insulation, that tiny amount of heat was probably being dissipated by the piston, linkage and flywheel. With the epoxy piston, it would seem to have nowhere to go, but I assure you the heat will find some path out, but it will not be an efficient path. I would guess that is why your engine is freezing up. I would like to see how it runs on hot water, if you don’t mind.

 

If I am right, it will not run very well. Next, if you remove the insulation and it starts running better, you will know it is not piston drag that was slowing it down but lack of heat transfer.

 

 

I haven't run the engine with the epoxy piston on hot water with any insulation. Just on a cup of hot water, without insulation, but it would not run at all, until I used some oil. That probably gave it some lubrication reducing the friction, as well as improving the seal. I didn't run it for very long before switching to ice, because I wanted to "break it in" and I knew it would run on ice unattended for hours and hours, if it ran at all.

 

I can make another video of my attempts to run it on hot water, but I believe the heat, if anything may have softened the epoxy causing even more drag, or at least running cold, the epoxy seemed to have a little less drag, maybe.

 

I don't know as another video will prove anything, but I can try running it on hot water with and without the sink insulated. In these experiments it seems like weird unexpected things keep happening.

 

Even on a nearly full mug of boiling hot water, though, I have not had any engine run for more than about three hours.

 

On ice, on the other hand, it seems like it will never stop. not really, but 33 hours seemed like nearly forever.

 

I attribute the difference in run time between hot water and ice, to the fact that ICE is phase changing, so can absorb more "latent heat" than water that is merely cooling without phase change, though other factors may be involved as well.

Edited by TomBooth
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TomBooth; thank you for posting this interesting topic, very brave of you to challenge both the second law of thermodynamics heat flow statement: ‘Heat flows spontaneously from a substance at a higher temperature to a substance at a lower temperature and does not flow spontaneously in the reverse direction’ and also Carnot’s principle, (An alternative statement of the second law of thermodynamics), ‘No irreversible engine operating between two reservoirs at constant temperatures can have a greater efficiency than a reversible engine operating between the same temperatures. Furthermore, all reversible engines operating between the same temperatures have the same efficiency’.

I believe heat engines could have been used on submarines. It would be surprising if the second law or Carnot’s principle were wrong, but I like the saying: ‘question everything you think doesn’t add up’.

You are welcome. I don't think I'm challenging ‘Heat flows spontaneously from a substance at a higher temperature to a substance at a lower temperature and does not flow spontaneously in the reverse direction’ at all though.

 

An engine is not "spontaneous", it is a carefully crafted work of engineering. Even a refrigerator or heat pump operates on the same principle.

 

I think Carnot efficiency  is also generally true, most of the time, though I think it has been widely misinterpreted. I think at any "Carnot efficiency" is the theoretical maximum efficiency between any two temperatures, at which point heat flow to the sink would in theory stop, because the engine has extracted so much heat as work that the temperature is brought down to equilibrium with the environment. So 20% efficiency does not mean that 80% of the heat is rejected to the sink, just that that "heat" is unavailable to do work. But this was all based on the idea that heat is a fluid.

 

Heat that cannot flow, though, is not actually heat, as heat is transfer of energy. At equilibrium there is no transfer of energy.

 

If "ALL THE HEAT" is conceived as all the 'potential energy' down to absolute zero, then "Carnot efficiency" just represents the AVAILABLE heat which is actually heat. The remaining 80% is potential energy below the ambient equilibrium baseline. It is mathematically accurate but the interpretation is wrong.

 

20% Carnot "efficiency" does not mean 80% of the heat passes through the engine to the sink. It means 80% of the theoretical "potential" kinetic energy all the way down from the ambient baseline to absolute zero is not really heat so it is unavailable.

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As an example.

 

Take boiling water at 212 Fahrenheit and apply it to an engine in a room at 85 Fahrenheit. That is a 127 degree temperature difference.

 

To get Carnot efficiency that has to be changed to Kelvin on an absolute scale. Why?

 

212 = 373.15

 

85 = 302.594

 

373.15 - 302.594 = 70.556

 

70.556 / 373.15 = 0.189 X 100 = 18.9%

 

That 18.9% "Carnot efficiency" on the absolute scale, is exactly the same thing as the 127 degree Fahrenheit temperature difference.

 

0 _ 10 _ 20 _ 30 _ 40 _ 50....... 300 _ 310 _ 320 _ 330 _ 340 _ 350 _ 360 _ 370 _ 380 _ 390 _ 400 _ 410 ...Kelvin

                                                        ^                                                                     ^

                                                     302K                                                              373K

                                                      85F                                                               212F

<-----------------81.1%-----------------><-------------------------18.9%-------------------->

 

<------------------------------------------------100%------------------------------------------->

Edited by TomBooth
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Carnot considered heat a substance. an actual thing. a fluid.

 

Add a cup of "caloric" to zero and you have one cup of caloric..... all the way up to ambient ->302K, call that 302 cups of fluid caloric.

 

My heat engine can only utilize a mere 18.9% of that body of fluid, that volume of "Caloric" substance that is somehow burned up or destroyed by my engine like firewood.

 

Carnot efficiency is nothing other than the temperature difference, or the actual heat available. But the remaining unused "Caloric" does not flow through the engine!

Edited by TomBooth
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As an example.

 

Take boiling water at 212 Fahrenheit and apply it to an engine in a room at 85 Fahrenheit. That is a 127 degree temperature difference.

 

To get Carnot efficiency that has to be changed to Kelvin on an absolute scale. Why?

 

212 = 373.15

 

85 = 302.594

 

373.15 - 302.594 = 70.556

 

70.556 / 373.15 = 0.189 X 100 = 18.9%

 

That 18.9% "Carnot efficiency" on the absolute scale, is exactly the same thing as the 127 degree Fahrenheit temperature difference.

 

0 _ 10 _ 20 _ 30 _ 40 _ 50....... 300 _ 310 _ 320 _ 330 _ 340 _ 350 _ 360 _ 370 _ 380 _ 390 _ 400 _ 410 ...Kelvin

                                                        ^                                                                     ^

                                                     302K                                                              373K

                                                      85F                                                               212F

<-----------------81.1%-----------------><-------------------------18.9%-------------------->

 

<------------------------------------------------100%------------------------------------------->

 

 

On the Kelvin scale, 0 to 300 K is 80% of the difference between 0 and 373 K.  300 K to 373 K makes up the additional 20 %, in round numbers. An engine that uses the difference between 300 K and 373 K to do work is 20 % efficient using this scale.

 

On the F scale, 0 to 85 F is 40 % of the difference between 0 and 212 F. 85 F to 212 F makes up the remaining 60 %, in round numbers. A calculation using this scale would say that same engine is 60 % efficient.

 

This is why we use standards based on the same scales not only for heat engines but in all of science.

 

How you are seeing these ratios as being the same, using two different scales, is a mystery to me.

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There is a bit of confusion here.

 

The engine ran for 33 hours ON ICE (or ambient heat, but ice as the "sink").

 

On a cup of boiling hot water, I have never been able to keep the engine running more than a few hours, with or without insulation.

On hot water, without insulation, the engine ran for about 2 hours and 20 minutes. With the top (sink) insulated the engine ran at a higher RPM but not much longer, barely more than three hours. However, at that time I was not measuring the water precisely, just pouring it from the kettle into the cup, about half full, so I really need to do those experiments over.

 

But, for your calculations above, on 1 cup of boiling hot water, (the large vacuum insulated mugs I used hold about 2 cups so half full is probably approximately 1 cup), the time factor should be reduced from 30 to 3, or more likely 2 1/2 hours.

 

Either way, I don't think a little toy engine is producing much power, but just FYI.

 

OK then, if one cup of water at 373 K cools down to ambient 300 K, it releases about 72,500 Joules of heat energy.

If it does that in 3 hours, that is 6.7 Watts of continuous power. At 20% efficiency, the work done to spin the engine is only 1.3 Watts continuous. So, the heat dissipated by the ambient sink is only a little more than 5 Watts, continuous power.

Imagine a resistor with 5 Watts of power dissipation, mounted on top of that aluminum top, in ambient air. You would hardly notice any increase in the T of the plate at all. It certainly would not be hot to the touch.

 

 

I attribute the difference in run time between hot water and ice, to the fact that ICE is phase changing, so can absorb more "latent heat" than water that is merely cooling without phase change, though other factors may be involved as well.

 

 

Yes, that is right. The latent heat for melting ice is 334 Joule/gram while the specific heat of water is only 4.186 Joule/gram/Kelvin. That’s why ice can melt for 30 hours in your vacuum flask while it only takes 3 hours for hot water to cool down to room temperature.

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On the Kelvin scale, 0 to 300 K is 80% of the difference between 0 and 373 K.  300 K to 373 K makes up the additional 20 %, in round numbers. An engine that uses the difference between 300 K and 373 K to do work is 20 % efficient using this scale.

 

On the F scale, 0 to 85 F is 40 % of the difference between 0 and 212 F. 85 F to 212 F makes up the remaining 60 %, in round numbers. A calculation using this scale would say that same engine is 60 % efficient.

 

This is why we use standards based on the same scales not only for heat engines but in all of science.

 

How you are seeing these ratios as being the same, using two different scales, is a mystery to me.

Absolute zero on the fahrenheit scale is −459.67 °F not zero.

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OK then, if one cup of water at 373 K cools down to ambient 300 K, it releases about 72,500 Joules of heat energy.

If it does that in 3 hours, that is 6.7 Watts of continuous power. At 20% efficiency, the work done to spin the engine is only 1.3 Watts continuous. So, the heat dissipated by the ambient sink is only a little more than 5 Watts, continuous power.

Imagine a resistor with 5 Watts of power dissipation, mounted on top of that aluminum top, in ambient air. You would hardly notice any increase in the T of the plate at all. It certainly would not be hot to the touch.

 

I think your argument contains a logical inconsistency. You start out with "if one cup of water at 373 K cools down to ambient 300 K, it releases about 72,500 Joules of heat energy." <--- That is the 20%

 

The 80% is all the remaining potential "heat" from 300K down to absolute zero that is supposed to be rejected to the sink.

 

In a steam engine, I suppose this makes some sense because all that "latent heat" if it can be called that, is actually contained in the molecules of H2O that actually do pass through the engine. The unused "heat" or internal molecular kinetic energy IS carried along through the cylinder and goes out through the valves and is "rejected" or exhausted

 

In a Stirling engine, though, no steam or air or other substance passes through only the 20% of additional added heat above the ambient baseline is in any way utilized.

 

Even if I take a bucket of water that represents 20% of a bathtub full of water and elevate it to pour through a turbine, and the entire bucketfull returns to the bathtub "sink", the 80% remaining in the tub did not pass through the engine.

 

In a Stirling engine even the 20% does not return to the tub because it is really energy that is converted, so never returns to the tub.

 

The other 80% never left it.

Edited by TomBooth
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Maybe redo that scale comparison a bit:



0 _ 10 _ 20 .... 300 _ 310 _ 320 _ 330 _ 340 _ 350 _ 360 _ 370 _ 380..(Kelvin)
                             ^                                                                      ^
                          302K                                                               373K
-459F                  85F                                                                212F

<------81.1%-------><------------------------18.9%--------------------->
<---------------------------------100%------------------------------------->

Edited by TomBooth
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