The "Ice Bomb" thermal engine

[swansont]

59 minutes ago, Tom Booth said:

Well, that's what happens with the liquefaction of gas using an expansion turbine.

The gas is compressed and cooled, then allowed to expand through a turbine. There is a load on the turbine, so the gas also has to perform work as it expands.

But we're not talking about a gas, we're talking about a liquid undergoing a phase change to a solid

59 minutes ago, Tom Booth said:

 I would say "must" is appropriate. Otherwise the process would not be reliable enough for industrial applications.

"Must" is your requirement then. Whether that actually happens isn't determined by the requirement.

59 minutes ago, Tom Booth said:

Also, I think ice can be much colder than 0°c

After you've turned it all to ice. A mixture of ice and liquid water (allowed to come to steady-state) will be at 0ºC. (similar w/ steam and water at 100ºC)

 

[exchemist]

1 hour ago, Tom Booth said:

There is no container within the cylinder. The engine's cylinder is the container.

Sure, there is some "stretching" on some infinitesimal scale, but the piston is designed to move or yield at the critical moment when the expansion force is at a maximum, but not before.

 

Well in that case you won't get any "explosion", will you? The piston will gently move out by 9% as the water freezes and, er, that's it. It can be made to do the same amount of work as your earlier ice bomb explosion, of course, but just in a less dramatic way.

Correction: Sorry I see you propose something that makes it go ping when the pressure has built up. Not sure what advantage that has, but fair enough, it will go ping, then.

 

Edited May 7, 2021 by exchemist

[Tom Booth]

1 hour ago, John Cuthber said:

 

If you supercool water (for example in the cylinder of some "engine") and then induce it to freeze- say by shaking, it warms up to 0C as it freezes.

That is quite interesting. If the water is super-cooled and thermally isolated, so it cannot absorb any additional heat from the environment. Say by supercooling inside a Dewar, before shaking it. Will this still happen? In other words, does the heat to warm up the ice come from the environment or from the release of internal energy, due to the rearrangement of molecules?

Also, I'm wondering what would happen if the water is super-cooled to an extremely low temperature very rapidly. Or does the energy to warm it up come from the shaking?

Anyway, I would be very interested in finding out more about that, if there is a reference.

Anyway, I may be over-generalizing. The liquifaction of gases by the Claude process may be different than what might take place when H2O does work while changing state from liquid to solid. Liquids and solids are not so closely tied up with temperature as gas, having other internal forces to draw from.

To be consistent though, I would think that if water freezes and expands, doing work in the process, the energy to do the work has to be drawn from somewhere. In a gas, there is a temperature drop. Exactly what happens when water freezes and performs work is another matter. But rumor has it that the force of expanding ice is enough to split a mountain in half. Such a seemingly irresistible force has to draw energy from somewhere.

Edited May 7, 2021 by Tom Booth

[John Cuthber]

14 minutes ago, Tom Booth said:

does the heat to warm up the ice come from the environment or from the release of internal energy, due to the rearrangement of molecules?

Release of internal energy. Supercooled water is unstable.

 

15 minutes ago, Tom Booth said:

Such a seemingly irresistible force has to draw energy from somewhere.

It does.
It draws it from whatever created the temperature difference in the first place.

On Earth, that's generally the Sun.

It's nothing magic; just physics.

[Tom Booth]

31 minutes ago, John Cuthber said:

 

It does.
It draws it from whatever created the temperature difference in the first place.

On Earth, that's generally the Sun.

It's nothing magic; just physics.

I mean, during the freezing process.

If the environment is drawing heat out of the water causing it to freeze, then when the ice expands within a cylinder with a moveable piston, and while expanding lifts, say 100,000 Pounds/square inch, which for a 10 inch diameter piston, works out to what?

Approximately 25 Million pounds?

With the environment colder than the ice, drawing heat out of the ice, during that process, the energy is not coming from the sun. Not directly anyway.

I think more likely from the big bang or something when the matter was first formed, before the sun came into existence.

 

13 minutes ago, Tom Booth said:

 

 

On a hot summer day I can sit and watch some ice slowly melt in my glass of lemonade.

To imagine the reverse process of taking away the same heat required to melt a few ice cubes can explode a cast iron "ice bomb" doesn't exact make a whole lot of sense to me.

Edited May 7, 2021 by Tom Booth

[MigL]

Take any badly poured concrete slab, that doesn't properly drain water underneath.
It experiences cyclic up/down movement yearly.
It heaves up during the winter when the water trapped underneath freezes, and returns back down during the thaw and settling of summer.

The cycle is only 1 per year, but with proper gearing you could probably get better 😀 .

[Tom Booth]

16 minutes ago, MigL said:

Take any badly poured concrete slab, that doesn't properly drain water underneath.
It experiences cyclic up/down movement yearly.
It heaves up during the winter when the water trapped underneath freezes, and returns back down during the thaw and settling of summer.

The cycle is only 1 per year, but with proper gearing you could probably get better 😀 .

Kind of my thoughts exactly. I've seen frost in the ground in an unheated basement lift the entire house 6 inches off the foundation 

In one unheated house I worked in, The oil furnace was crushed between the slab below it and the basement ceiling. I mean really crumpled. I thought the ceiling was coming down but was unable to jack up the basement ceiling.

It wasn't until spring that I realized it was due to frost under the slab the furnace was on, that raised it up several inches, crushing the furnace against the ceiling like a soda can.

I was doing electrical work and several wires were trapped between the furnace and ceiling. I couldn't get them out.

Returning in the spring, I was like, what the....

There was plenty of space above the furnace. The floor wasn't coming down, the furnace had been pushed up by the ice under the floor.

Edited May 7, 2021 by Tom Booth

[Tom Booth]

11 hours ago, exchemist said:

Well in that case you won't get any "explosion", will you? The piston will gently move out by 9% as the water freezes and, er, that's it. It can be made to do the same amount of work as your earlier ice bomb explosion, of course, but just in a less dramatic way.

Correction: Sorry I see you propose something that makes it go ping when the pressure has built up. Not sure what advantage that has, but fair enough, it will go ping, then.

 

I used the title "Ice Bomb" mostly for dramatic effect, and to identify the crude principle involved in the most dramatic way. There are lots of demonstrations on YouTube. Mr Wizard is probably my favorite, but posting videos here seems to be generally frowned upon.

You can put a teaspoon of gasoline in a can and shake it up to distribute the fumes evenly then ignite it and watch it explode, to demonstrate the energy stored in a teaspoon of gasoline too, but if we want to utilize that energy, build an engine that can put it to practical use, then the "explosion" has to be carefully controlled and regulated and synchronized with the mechanical apparatus of the engine.

Standing next to a running automobile it may not be apparent that multiple small explosions are taking place inside sealed containers that in effect, blow apart, without actual damage, then come back together and blow apart again.

I don't know, engineering wise, if an ICE BOMB engine is actually doable. MigL's idea of a simple gear system with a block of concrete being lifted and let back down by freezing and thawing is at least more readily achievable.

What I really want to get to the bottom of though is the physics of being able to harness energy by a method that involves removing energy from a system.

if we can all at least agree that some kind of Ice machine that harnesses the energy of expanding water is possible, that's a major step along the road to talking about the scientific and philosophical implications.

If we are able to get at the, apparently very powerful INTERNAL ENERGY of atoms in one way, maybe we can do it in other ways.

I think it is agreed, that the energy of expanding ice is coming from some form of stored internal energy, not from any external energy in the surrounding environment acting on the water molecules. The outside environment is taking away energy.

studiot pointed out earlier:

Quote

"The way to calculate this is not from the equations because water is an exception to the normal pattern."

That is a very interesting statement to make, and is actually the point I was hoping to get across when I started this thread.

17 hours ago, John Cuthber said:

Fundamentally, the idea  depends on having a large "cold body" that you can use for cooling.
And if you have that, you can use it to run a "stream engine" with, for example, butane, as the working fluid.
 

This is getting somewhere, I think.

But does the cold body actually have to be large, like a stream, lake or ocean?

What about a single teaspoon of water?

A small chip of ice?

I believe in the idea that if something works in principle it should work on just about any scale. An electric motor can be thumbnail size or as big as a house. Same for gasoline engines, refrigeration systems, etc.

Why not build a tiny machine that takes a teaspoon of water that can be placed in a household freezer compartment?

The water/ice could expand pushing some kind of piston in a cylinder connected to a rod that compresses a spring with some kind of ratchet mechanism. We don't really need a glacier and hot springs next to each other to get some actual measurements and readings, just a small working model.

[Sensei]

(without reading comments above, so maybe somebody already pointed it out)

A perfectly sealed object with fluid inside will behave differently than the same object with open air access, i.e. different temperatures and pressures will be required to change the state of matter.

It is used to stupidify people by so called "miracle" e.g.
https://www.google.com/search?q=naples+saint+blood+liquify

which, from time to time, changes state from solid to liquid, and vice versa.

Basically, water put it sealed bottle, won't freeze at 0 C and won't boil at 100 C. In the perfect gas equation v volume variable is constant so two other variables must change accordingly instead.

[Tom Booth]

This tends to be about the point where the discussion gets locked or I get banned from the forum, but what the hey, you only live once right?

What if, assuming we can generate energy by taking away energy as we've been discussing, suppose we store the energy that we took away somehow, so we can put it back later to repeat the cycle?

If anyone knows how a refrigerator works, on the back of most refrigerators there are coils of pipe containing refrigerant that get very hot while the refrigerator is running. A refrigerator is designed for one purpose, to keep things cold. The heat removed is never utilized for anything, it just gets thrown away. But is that really necessary?

So we get the heat out of the ice, which, in theory could be stored or used in some way, and also the ice expands which can generate some usable energy perhaps.

I have heat in one hand and cold in the other and ice expanding and generating mechanical force, winding up a spring or something.

What if instead of returning the heat that was taken out and stored, we just take the device out of the freezer and let it thaw out for a while. Lets say there is a little hole or small trap door so we can get the machine out without actually letting additional heat into the freezer.

Now the machine is absorbing ambient heat from the atmosphere to thaw the ice.

I'm wondering, as the ice thaws, can we also harness additional energy as the expanded ice contracts? Have a reverse ratchet mechanism that winds another spring. Why not? I think this would actually be harvesting atmospheric pressure that presses down on the ice as it reduces in volume.

When the ice is fully thawed, put it back in the freezer and the cycle continues. We can run the refrigerator and store additional heat being extracted from the water/ice-machine, get more mechanical energy from the expanding ice, and we managed to mostly maintain our refrigerated space, while the heat to thaw out the ice we get for free from the atmosphere.

What to do with all this stored heat and stored up mechanical power in springs and what not?

Can we use it, perhaps, to run the refrigerator when necessary, to make up for the small unavoidable losses?

I don't really understand why these kinds of speculations and thought experiments need to be outlawed by the scientific community at large. I don't really know how many discussion topics I've started over the years on Science forums, that have been locked or deleted or removed, or from which I've been banned.

Water freezing and expanding is not the only "exception to the normal pattern" to be found. I think there are gases. Actually I think ALL gases, within certain specific temperature ranges, expand when cooled and/or contract when heated.

Probably the "Ice Bomb" engine is not really a viable source of energy, but I find it rather stimulating and fun to think about, I'm not sure why I should be penalized for that.

I might actually take the time someday soon to build some small model and put it in the freezer, or leave it outside in winter, and try and measure how much force it can actually generate, just out of curiosity.

 

This is an interesting ratchet type winding mechanism invented by James Cox in 1760 that could be useful for this sort of thing. It was used to wind a clock using changes in barometric pressure. A simplified version would be a sealed canister of air. As a storm approaches and the pressure changes the canister swells and contracts, pretty much continuously as the weather changes. This ratchet works in both directions. Winding in the same way regardless of which way the pressure changes. The Cox clock used 150 pounds of Mercury, but the same basic principle.

 

I think the clock ran, keeping itself wound up by changes in atmospheric pressure for over 100 years or something like that until the mercury was removed to move it.

 

Edited May 8, 2021 by Tom Booth

[exchemist]

45 minutes ago, Tom Booth said:

This tends to be about the point where the discussion gets locked or I get banned from the forum, but what the hey, you only live once right?

What if, assuming we can generate energy by taking away energy as we've been discussing, suppose we store the energy that we took away somehow, so we can put it back later to repeat the cycle?

If anyone knows how a refrigerator works, on the back of most refrigerators there are coils of pipe containing refrigerant that get very hot while the refrigerator is running. A refrigerator is designed for one purpose, to keep things cold. The heat removed is never utilized for anything, it just gets thrown away. But is that really necessary?

So we get the heat out of the ice, which, in theory could be stored or used in some way, and also the ice expands which can generate some usable energy perhaps.

I have heat in one hand and cold in the other and ice expanding and generating mechanical force, winding up a spring or something.

What if instead of returning the heat that was taken out and stored, we just take the device out of the freezer and let it thaw out for a while. Lets say there is a little hole or small trap door so we can get the machine out without actually letting additional heat into the freezer.

Now the machine is absorbing ambient heat from the atmosphere to thaw the ice.

I'm wondering, as the ice thaws, can we also harness additional energy as the expanded ice contracts? Have a reverse ratchet mechanism that winds another spring. Why not? I think this would actually be harvesting atmospheric pressure that presses down on the ice as it reduces in volume.

When the ice is fully thawed, put it back in the freezer and the cycle continues. We can run the refrigerator and store additional heat being extracted from the water/ice-machine, get more mechanical energy from the expanding ice, and we managed to mostly maintain our refrigerated space, while the heat to thaw out the ice we get for free from the atmosphere.

What to do with all this stored heat and stored up mechanical power in springs and what not?

Can we use it, perhaps, to run the refrigerator when necessary, to make up for the small unavoidable losses?

I don't really understand why these kinds of speculations and thought experiments need to be outlawed by the scientific community at large. I don't really know how many discussion topics I've started over the years on Science forums, that have been locked or deleted or removed, or from which I've been banned.

Water freezing and expanding is not the only "exception to the normal pattern" to be found. I think there are gases. Actually I think ALL gases, within certain specific temperature ranges, expand when cooled and/or contract when heated.

Probably the "Ice Bomb" engine is not really a viable source of energy, but I find it rather stimulating and fun to think about, I'm not sure why I should be penalized for that.

I might actually take the time someday soon to build some small model and put it in the freezer, or leave it outside in winter, and try and measure how much force it can actually generate, just out of curiosity.

 

It's because you don't understand the science and make statements that are not credible, I expect. 

It looks to me as if we need to talk a bit about enthalpy, H.

Enthalpy, H=U +PV, where U is the internal energy of a system and PV is the work done done on, or by, the system due to its expansion or contraction under any prevailing pressure during changes to the system. In chemistry we generally work with enthalpy because most chemical reactions are carried out at atmospheric pressure. So any changes in volume during a reaction will either push back the atmosphere (if the reacting system expands) or get pushed on by the atmosphere (if it contracts).

These effects alter the total amount of energy measured as coming out or going into the reaction system.  

So, in the case of ice freezing, Latent Heat of Fusion comes out of the water as it freezes. If the system is open to the atmosphere, the amount of heat that comes out will be a bit less than if the water was being frozen under vacuum.  That's because some of the internal energy released, as the bonds in the ice crystal form, goes into pushing back the atmosphere as the ice expands. In a vacuum there is no work done, so all the internal energy from bond formation comes out as Latent Heat.

If you now put the water in a cylinder underneath a huge weight and freeze it, the heat that comes out during freezing will be less still, because more of the internal energy in the forming bonds goes into pushing up the weight.

So in summary, there is a fixed amount of internal energy, per gram - per molecule, in fact - that is released when ice forms. How much comes out as Latent Heat depends on the PV work the water has do as it freezes.

There is no free lunch here.  

Edited May 8, 2021 by exchemist

[Tom Booth]

15 minutes ago, exchemist said:

 

If you now put the water in a cylinder underneath a huge weight and freeze it, the heat that comes out during freezing will be less still, because more of the internal energy in the forming bonds goes into pushing up the weight.

I'm very glad you pointed that out! So I don't have to.

Work is performed converting the heat into work, so less heat to remove from the freezer! Excellent!

[exchemist]

6 minutes ago, Tom Booth said:

I'm very glad you pointed that out! So I don't have to.

Work is performed converting the heat into work, so less heat to remove from the freezer! Excellent!

Er, not quite. Chemical energy is converted into work as well as heat, as the bonds form during crystallisation.

But it would indeed mean less heat for the refrigeration to remove, yes. 

Edited May 8, 2021 by exchemist

[Tom Booth]

12 minutes ago, exchemist said:

 

But it would indeed mean less heat for the refrigeration to remove, yes. 

Marvelous! so if the "refrigerator" is Very very well insulated. A Dewar within a Dewar wrapped in Aerogel blankets a few times and our machine does lots and lots of heavy lifting we could keep the process of intermittently harvesting atmospheric heat going on for some time without having to run the refrigerator at all.

Edited May 8, 2021 by Tom Booth

[exchemist]

9 minutes ago, Tom Booth said:

Marvelous! so if the "refrigerator" is Very very well insulated. A Dewar within a Dewar wrapped in Aerogel blankets a few times and our machine does lots and lots of heavy lifting we could keep the process of intermittently harvesting atmospheric heat going on for some time without having to run the refrigerator at all.

Well, you still need to induce the water to freeze, of course. And the freezing point will be depressed by the pressure, because the pressure will shift the point of equilibrium between water and ice. So you will need a colder fridge.

[Tom Booth]

20 minutes ago, exchemist said:

Well, you still need to induce the water to freeze, of course. And the freezing point will be depressed by the pressure, because the pressure will shift the point of equilibrium between water and ice. So you will need a colder fridge.

OK, so the colder we can get the fridge, the more work we can get out of the expanding ice. I'm not sure that is necessarily a major problem, but something to consider for sure. It may be that we, or I or whomever might try this, ends up chasing their own tail so to speak, trying to get the fridge cold enough to do enough work to get the fridge cold enough to do enough work to keep the fridge cold enough to keep the fridge cold, etc. etc.

I hate to have to mention the apparently unmentionable, as it usually gets me in trouble, but a pretty smart fellow wrote about this same problem back in 1900 and concluded that if the machine did work lifting the weight efficiently enough, there would be little heat to be removed from the fridge and the fridge would have to run so infrequently that the machine could produce more work than would be needed to maintain the fridge at a sufficiently cold temperature.

I don't know if he was right or wrong, but it seems to me to be worth a try. It doesn't seem that the contraption would be all that difficult to build. The worst that could happen is it doesn't work.

Or, maybe the worst that could happen is it does and the mysterious men in black come knocking.

[exchemist]

43 minutes ago, Tom Booth said:

OK, so the colder we can get the fridge, the more work we can get out of the expanding ice. I'm not sure that is necessarily a major problem, but something to consider for sure. It may be that we, or I or whomever might try this, ends up chasing their own tail so to speak, trying to get the fridge cold enough to do enough work to get the fridge cold enough to do enough work to keep the fridge cold enough to keep the fridge cold, etc. etc.

I hate to have to mention the apparently unmentionable, as it usually gets me in trouble, but a pretty smart fellow wrote about this same problem back in 1900 and concluded that if the machine did work lifting the weight efficiently enough, there would be little heat to be removed from the fridge and the fridge would have to run so infrequently that the machine could produce more work than would be needed to maintain the fridge at a sufficiently cold temperature.

I don't know if he was right or wrong, but it seems to me to be worth a try. It doesn't seem that the contraption would be all that difficult to build. The worst that could happen is it doesn't work.

Or, maybe the worst that could happen is it does and the mysterious men in black come knocking.

Haha, I did wonder if you were a closet free energy crank, what with all your talk of being banned and everything.

Can you refer me to a link to this 1900 fellow? Clearly he wasn't quite as smart as all that - or maybe he wanted to pull a few people's legs. Like you perhaps. 

[Tom Booth]

8 hours ago, exchemist said:

Haha, I did wonder if you were a closet free energy crank, what with all your talk of being banned and everything.

Can you refer me to a link to this 1900 fellow? Clearly he wasn't quite as smart as all that - or maybe he wanted to pull a few people's legs. Like you perhaps. 

Sure, quite happy to oblige, though posting outside links, requiring a lot of reading is discouraged on some science forums, maybe I'm thinking of someplace else, but for everybody's convenience it might be a good idea to post the relevant passages as it is a very long and rambling article.

Here is one link where the PDF can be freely downloaded, though, there is a copyright notice apparently applying to this particular digital version, there are others available and the text itself is public domain.

https://www.unz.com/print/Century-1900jun-00175

Scroll down or search for the section about "Self Acting Engine", or "Carnot" or "Lord Kelvin" or "Sir Wilham Thomson". (Should be William, but there is an OCR error).

The most relevant section begins with the title: "A DEPARTURE FROM KNOWN METHODS—POSSIBILITY OP A "SELF-ACTING" ENGINE OR MACHINE, INANIMATE, YET CAPABLE, LIKE A LIVING BEING, OF DERIVING ENERGY PROM THE MEDIUM—THE IDEAL WAY OF OBTAINING MOTIVE POWER." (Emphasis:caps in the original. OCR errors corrected.) Page 200 of the magazine article. Page 26 forward of this particular PDF.

I think he was absolutely serious and quite dedicated to the cause, even if mistaken.

 

Here is a better Google version, apparently scanned, photo-correct.

Again, scroll to page 200 or faster, search for text such as: self-acting engine

https://babel.hathitrust.org/cgi/pt?id=mdp.39015013530053&view=1up&seq=218&q1=self acting engine

Unfortunately the PDF includes three issues of the magazine, so it may be the second page 200.

Edited May 8, 2021 by Tom Booth

[Tom Booth]

Reading these passages, it seems almost all Tesla's inventions revolved around this particular pursuit for many years, or comprised various elements of his "self Acting Engine" which was a combination of several of his inventions.

He says his work was delayed, due to his workshop burning down, then he deduced,  the engine would work, but would not be as effective as he had originally hoped, in the end he became distracted by other discoveries and projects.

The truth may be, he never succeeded because what he was attempting was actually an impossibility. A violation of the second law of thermodynamics, but I admire his perseverance and tenacity.

I'm not entirely sure that his original premise was not in fact correct. That less energy would be required to maintain, what he describes as a "cold hole" with some type of heat pump than could be harvested as a result from the heat of the surrounding "the ambient medium" which the existence of the "cold hole" would make available. For the very same reason pointed out above. The conversion of heat into work by the device, would result in there being less heat to remove than could be converted into other forms not requiring removal. and what heat did enter into the system; "can
just be raised up with its own energy, and what is converted is clear gain."

Edited May 8, 2021 by Tom Booth

[exchemist]

2 hours ago, Tom Booth said:

Sure, quite happy to oblige, though posting outside links, requiring a lot of reading is discouraged on some science forums, maybe I'm thinking of someplace else, but for everybody's convenience it might be a good idea to post the relevant passages as it is a very long and rambling article.

Here is one link where the PDF can be freely downloaded, though, there is a copyright notice apparently applying to this particular digital version, there are others available and the text itself is public domain.

https://www.unz.com/print/Century-1900jun-00175

Scroll down or search for the section about "Self Acting Engine", or "Carnot" or "Lord Kelvin" or "Sir Wilham Thomson". (Should be William, but there is an OCR error).

The most relevant section begins with the title: "A DEPARTURE FROM KNOWN METHODS—POSSIBILITY OP A "SELF-ACTING" ENGINE OR MACHINE, INANIMATE, YET CAPABLE, LIKE A LIVING BEING, OF DERIVING ENERGY PROM THE MEDIUM—THE IDEAL WAY OF OBTAINING MOTIVE POWER." (Emphasis:caps in the original. OCR errors corrected.) Page 200 of the magazine article. Page 26 forward of this particular PDF.

I think he was absolutely serious and quite dedicated to the cause, even if mistaken.

 

Here is a better Google version, apparently scanned, photo-correct.

Again, scroll to page 200 or faster, search for text such as: self-acting engine

https://babel.hathitrust.org/cgi/pt?id=mdp.39015013530053&view=1up&seq=218&q1=self acting engine

Unfortunately the PDF includes three issues of the magazine, so it may be the second page 200.

Ah, so it was Tesla, again. Here we go....

And he was looking for a perpetual motion machine of the second kind, that is to say one operating with only a heat source and no heat sink. Fine, we all know how that ends. 

But I see you are personally quite serious about this: https://experiment.com/projects/hohohltuqpivlpspyewk/methods

Now I understand why you talk of getting banned, men in black etc.   

 

[Tom Booth]

3 minutes ago, exchemist said:

 

Now I understand why you talk of getting banned, men in black etc.   

 

And why do you think that is?

It was intended as a joke but who knows. Sometimes it seems there is some grain of truth behind some of it.

The US government does at times exercise jurisdiction over inventions with potential military application.

I'm not sure all the rumors are entirely without foundation, but tend not to take the conspiracy theories seriously.

[swansont]

2 minutes ago, Tom Booth said:

The US government does at times exercise jurisdiction over inventions with potential military application.

I think a device that would work as slowly and inefficiently as this is going to be safe

[Tom Booth]

Just now, Tom Booth said:

And why do you think that is?

It was intended as a joke but who knows. Sometimes it seems there is some grain of truth behind some of it.

The US government does at times exercise jurisdiction over inventions with potential military application.

I'm not sure all the rumors are entirely without foundation, but tend not to take the conspiracy theories seriously.

The banning of discussion on the subject, locking threads, suspending my account on forums, is certainly real enough, for what is perceived by the forum moderators, no doubt to be legitimate reasons.

[exchemist]

4 minutes ago, Tom Booth said:

And why do you think that is?

It was intended as a joke but who knows. Sometimes it seems there is some grain of truth behind some of it.

The US government does at times exercise jurisdiction over inventions with potential military application.

I'm not sure all the rumors are entirely without foundation, but tend not to take the conspiracy theories seriously.

I don't think even the Russians would see military potential in this ice engine of yours!

But I was thinking about it this afternoon. It could be interesting to distill it down to its simplest. You have a vertical cylinder with water in it, a piston and a ratchet so that when it freezes it lifts a weight and when it melts, the weight can't fall back down. You alternately connect the cylinder to a warm reservoir at say 20C and a cold reservoir at say -20C. The warm reservoir provides heat to melt the ice and the cold reservoir freezes it again. What happens? 

You start with water, connect to the cold reservoir and freeze the water. Heat flows into it, corresponding to Latent Heat of Fusion minus the work done in lifting the weight. Then you connect to the warm reservoir. Heat flows from it to the cylinder to melt the ice, this time the full Latent Heat of fusion, as the water is no longer under pressure, thanks to the ratchet. So you have  a heat flow from warm to cold, with some of the heat being converted to mechanical work. 

It's a normal heat engine, really, isn't it? 

 

[Tom Booth]

Here, I would have loved to answer Swansont's last question on the thread but got locked out before I could answer. Apparently because I posted a video that supported my statement that a Stirling engine is functionally, exactly the same as  a Stirling cryo-cooler:

https://www.scienceforums.net/topic/122721-heat-engine-experiments-and-2nd-law-of-thermodynamics/#comments

Or if the discussion were at least allowed to continue, maybe he could have set my thinking straight on the subject under discussion.

Which again, as with this thread, had to do with how engine "Carnot efficiency" is calculated, and the implications.

48 minutes ago, exchemist said:

I

It's a normal heat engine, really, isn't it? 

 

That's open for debate I guess.

I don't see it as quite normal because positive work is carried out during the portion of the cycle when heat leaves the system.

That is the opposite of a conventional heat engine that produces positive work while heat is being added.

I think, though I'm not entirely certain, that this reversal results in some kind of corruption of the accepted formula for calculating heat engine efficiency, though I haven't actually worked that out mathematically.

Earlier Swansont made a statement which I latched onto as confirmation that the usual formula breaks down or doesn't apply, because the way water expands when frozen is a deviation from the expected norm.

Edited May 8, 2021 by Tom Booth