Tom Booth

Ok, I'll have to take your word for it, But I'm still convinced that the combined effects of JT, heat loss from compressed air held back in the mouth, work done by the gas as it expands escaping pressurization through pursed lips pushing air aside, cooling from expansion itself, and the combined synergistic effect of all these elements put together, all as a consequence of the blowing through pursed lips, or a restriction, throttle, orifice This cooling method is so widely used everywhere in every day life and in so many vital industrial processes I hesitate to just dismiss it as a contributing factor. I don't think it is so much what happens outside the mouth after the air escapes, as what happens inside when the air is being compressed causing the temperature to rise, while also having time to equalize with the body temperature. The inside walls of the mouth and lips as well as the lungs acting as heat sink. A basic principle of refrigeration. Also, the relatively high velocity air stream produced does not allow much time for the expanding air stream to reabsorb heat it lost to the lungs and mouth until it reaches the destination; the cup of soup. However it is broken down, or whatever technical name(s) anyone wants to apply to it. Pursing the lips reduces the temperature for a variety of secondary reasons. IMO. All of which disappear without such a restriction. My opinion or intuition doesn't make it fact, of course. Another thought that occurs to me is that, if blowing a stream of air across the surface of hot soup or tea, cools the surface, this might very well drastically reduce evaporation, as evaporation relies mainly on the escape of hot molecules at the surface.

There is a little confusion between different experiments, 1) heat engine running on hot water 2) heat engine running on ice (actually ambient heat) Regardless, If heat flows into the engine to be converted into mechanical energy bringing the temperature of the gas within the engine down to the same temperature as the ice (the sink), no matter how well insulated, given the limitations of my little home laboratory in my kitchen, the ice, OUTSIDE OF THE ENGINE, is still subject to some heat infiltration from the environment, and so will eventually melt, even if no heat is reaching the ice through the engine itself. As insulated as I could get it, the engine (running on ice) ran for 33 hours continuously on a single coffee cup size mug full of ice. ("Running on ice" being a misnomer of course. The engine, properly speaking, was running on ambient heat) Obviously the ice, serving as the "sink" could not be isolated from the heat of the environment 100% even if the engine was actually cooling it slightly. Granted, this may not be so obvious to anyone not as familiar with Sterling engines. But 33 hours is a very long time. Typically the engine would run no more than a few hours on a cup of boiling water. even a similarly very well insulated cup of boiling water. The heat from the boiling water enters the engine and is converted into work and eventually all the heat is consumed, or used up. Running on AMBIENT HEAT, the heat enters the engine and is converted into work. But is it possible for the ambient heat to get used up or fully consumed by the engine like the finite source of heat represented by the cup of hot water? Not as long as the sun is shining. A control using the same set up with the engine just sitting on a cup of ice, not running, resulted in the ice melting in 27 hours. The engine apparently kept the ice cool and prevented it from melting for about 5 hours by converting the incoming heat into work. This is similar to the "Ice Bomb" engine converting heat into work in the freezer, so the freezer has to run less often to keep the ice cool. Though the Ice Bomb example is only a thought experiment, it is intended to illustrate the same principle as the actual Stirling Engine experiments. I'm sorry if this may be perceived as breaking the rules here by resurrecting a closed topic, but I think this is important and I believe it worthwhile to put this out to whomever might listen, especially the scientific community.

That's about 87.7 grams pressure per square inch, if my use of an online calculator can be trusted. But I have studied this phenomenon in some depth, and from what I've read, the effect is (or can often be) cumulative. That is something rarely mentioned in the textbooks. That is, there is a temperature drop that may be compounded over time. The cooling effect the first instant is added to that of the second, etc. So what may look like almost nothing on paper, in reality can be quite significant. Some sources also say a "normal person" may produce a pressure from 1 to 2 psi. which seems significantly higher than what you site, for people with "medical conditions". I'm thinking specifically of the "Joule-Thompson Effect". I'm not sure that is the same thing as adiabatic expansion exactly.

Sorry, my mistake. The video about Stirling cryo-coolers was another thread that was locked and moved to "speculations". How is the video "speculation"? It was produced by Phillips Cryogenics, a company that builds the things. I should think they would know. I was simply saying the thread was locked. The final post was yours and asked me a specific question. It would have been nice to have had the opportunity to answer you. That is all. This was the context of the question. I'm not trying to reopen the thread, just FYI. I don't want to be rude by not responding, or your thinking I didn't answer. Why? No... If no heat were rejected, your efficiency would be 100% You need to explain why you think this is so. IOW, explain why your ice melts, if no heat is flowing Again, you need to explain why you think this is so Actual thermodynamics doesn’t work this way. Oh, in that other thread I was told But, a lot of ground was covered, and exactly what "this subject" was specifically, who knows. My experiments? Thermodynamics generally? Anyway, I stayed in the corner for nearly a year. It seems obvious however, the issue was with the topic itself, apparently. What specifically? Who knows. Anyway, Why ? Because in a heat engine, heat is "rejected" to the sink through a metal plate, a heat exchanger. Heat only flows spontaneously from hot to cold. If the gas in the engine has reached the same temperature as the sink, (the ambient air outside the engine) how is any heat transfered to the sink?

The thread was locked, and is still locked. No specific reason was given so I can only speculate, but posting that video seemed to be the immediate issue, or my argument that it was certainly Germain to the conversation. It supported my argument from what should, I think, have been considered a reliable and authoritative source on the subject. You may not know how these threads relate to one another, but they most certainly do.

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. 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.

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.

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.

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."

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.

Off topic? That was the OP's theory, plain as day. The general story, the fable, is not any kind of theory to be tested. A question is not a theory to be tested. Certainly other variables, like the cupped hands could and should also be isolated and tested, one at a time and in combination before any hard conclusions are drawn. You are right to point out that there are other variables and possible contributing factors, but how something feels to the hands subjectively is not always reliable and I'm not sure how it was deduced that one method or the other of blowing on the tea was effective or not, or more or less effective. You seem to be hastening to discard the OP's original premise without ever actually testing it or proving it wrong. I do agree that one pet theory or conclusion should not be elevated over another, and strictly speaking, to say: "the ONLY variable appears to be the shape and size of the aperture", is overlooking the many other variables you point out, and no doubt many more that could be isolated and tested. But a theory is not "off topic" or "unscientific", just because there are alternative theories that could also be valid. How do you support that conclusion? It appears to be simply opinion without documented evidence. Has anyone ever actually measured the pressure drop? The actual temperature? Entrainment could be a causative factor, but adding more ambient air into the stream might increase the temperature of the stream. It might also increase the impact of the stream as with the "air amplifier" type device, increasing the pressure or speeding evaporative cooling, but I think it is premature to just dismiss what the OP suggests "seems to be" the most obvious or "only" variable.

I read, and now have reread both. I come to much the same conclusion. The theory being investigated is does blowing through pursed lips or open mouth result in cooling/heating, or rather, does the shape of the orifice make the difference. A scientific method would endeavor to eliminate all variables other than the variable in question: the shape of the orifice. Open or restrictive. Lungs, tea, cupped hands, human flesh, evaporative cooling, and potentially biased and subjective human interpretations etc. are all variables that could skew the results.

I don't think using cupped hands is without flaw as an experiment the chamber created, as you point out, causes increased pressure which modifies the conditions and changes the temperature of the air. Try the same experiment on the open back of the hand. I don't know about you, but I can feel a distinct difference. A thin stream of air through pursed lips feels cooler than the hot breath from an open mouth. If the hand it too close though, there will be an increase in pressure from the thin stream, much the same as with cupped hands and no noticable difference will be felt. A more objective test might be to breath/blow on a thermometer. Or better yet, use some sort of mechanical bellows and eliminate the human subjective element altogether. What I do know for sure is that the orifice in a vapor compression system plays a critical role in refrigeration. A "fixed orifice" in a duel heating and cooling system works both ways. "pursed lips" for cooling and "open mouth" for heating. A kind of check valve that restricts flow through a small orifice one way for cooling but opens up for unrestricted flow when the system is reversed for heating.

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.

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.

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!

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.

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

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.

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. 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.

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.

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, 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. The resulting energy loss from the gas due to the combined cooling from expansion and cooling from work output causes the gas to cool instantaneously and suddenly condense before it leaves the turbine. I would say "must" is appropriate. Otherwise the process would not be reliable enough for industrial applications. Also, I think ice can be much colder than 0°c And even liquid water can be super-cooled.

I'll have to reread that and study it again and again, but I have before from other texts and, well, it ends up in my mind seeming to be a new name for the abandoned "caloric". The caloric, having been abandoned in theory, but necessary for the math to work out as previously, it was resurrected as "entropy". That's about as much sense as I can make of it, anyway. Boiling happens at constant temperature as well, but a constant heat input is still going on to make it happen. Is it not also true that freezing requires continuous heat removal? The freezing process doesn't happen without energy exchange with the environment Work output is also energy exchange with the environment that results in a drop in temperature. It doesn't "stretch", any more than a regular engine stretches when a compressed fuel/air mixture is ignited. For my fanciful invention to work, I imagine that the piston would have to be very heavy in order to contain the expanding ice long enough for an explosive force to develop, at that moment when the expansion pressure is at a maximum, the piston passes TDC, (or I think BDC in this case) and begins to move away (due to energy stored in a flywheel) just as the ice explodes!

Trying to understand entropy fogs up my brain like a car windshield on a cold morning with no defroster. I think the Ideal "ice bomb engine" would contain the freezing water long enough, and the weight or load on the piston would be just heavy enough, (like in the compression stroke of an engine) that the piston would fly off from the sudden explosive force leaving a vacuum behind in the cylinder that would cause the water to boil under such low pressure and vaporize, causing further expansion. Then the gigantic piston would come crashing back down as the super-cooled water vapor (cooled due to the sudden violent expansion) condensed back into water, then as it continued to cool and freeze back into ice, the process would repeat itself. The timing would have to be very precise so that the piston reached full compression just as the water re-freezes. Or something like that.

One more thought comes to mind. If water freezes and expands, and is made to perform some useful work in the process, it would seem to follow that having lost heat energy as work output, the resulting ice should end up extra cold. Heat and work being equivalent. So an additional amount of heat will be needed to bring the ice formed under high compression back to a liquid state in order to make up for the heat lost to work output during the freezing process.