Tom Booth

Great ideas! I'll get to work on that right away! LOL

BTW, I do have a question. My original engine design works similar to and/or incorporates heat pump/refrigeration. In thermodynamics, is a vapor compression system, (refrigerators, heat pumps, freezers etc ) considered an "open system" or a "closed system", so does the second law apply or not? The "working fluid" is contained in a closed loop, but part of the "system" is the heat exchangers and the air being blown through them. Some say the second law applies to everything because the whole universe is a closed system, so... How exactly do we determine if a system is open or closed so we know if the second law is supposed to apply or not. It all seems vaguely philosophical to me with no clear cut answer.

Years ago I designed a heat engine. As a lifelong engine mechanic and repair person I thought it was a great design. I was told it would not work because it violated the second law. Now I'm doing experiments with model heat engines. I posted results on another forum. The discussion was locked and I was banned, because the moderators determined it was "a perpetual motion machine of the second kind" and that it violated the second law. (Or would if it was real). How does it violate the second law? is actually MY question! I'm not saying it does, that is what OTHER PEOPLE have been throwing in my face for the past 25 years. If there is no such violation that's wonderful news to me!

I think in general what I'm examining or testing is the nature of heat, and how it really interacts with a heat engine, or how it is utilized by a heat engine. Popular ideas or statements regarding how these engines work and what their potential may be does not square well with my own experience. For example, above, the statement: " This system is ~20% efficient because ~80% of the energy goes into heating the cold plate and the reservoir it’s coupled to. " (Not to pick on Swansont or anyone in particular) Generally this 80% pass through of heat into the sink is not what happens. Here is a link to another experiment conducted by someone else years ago using a thermal imaging camera. As can be seen in this thermal image of a running Stirling engine on a hot cup of water compared with a non operational dummy engine. In the same environment the real heat engine is clearly maintaining a cold temperature. The heat is not passing through to the top plate. In my own experiments I found the same situation. The bottom plate above boiling hot water was too hot to touch. I'm sure hot enough to raise a blister. At the same time the top plate remained cool to the touch. This does not seem to support the common assumption that the majority of heat passes right through the engine. In my experience virtually no heat makes it through these engines to the sink. Also, nearly all the incidental and parasitic heat loses are preventable to a great degree with proper insulation. The implications are far reaching, IMO. Source: https://concord.org/blog/an-infrared-investigation-on-a-stirling-engine/

I'm finding it a nearly hopeless task to try to sort out what your thinking may be in regard to how a Stirling engine operates. I don't mean that to be insulting or anything. It took me literally years of dedicated study and research to arrive at an understanding of how these engines work. It is not intuitive, yet, it really is not complicated, it just doesn't make sense, in some ways. For example, a Stirling engine actually, it could be said; "destroys heat". Heat goes into the engine and goes out of existence. It no longer exists in the form of energy we recognize as sensible heat. In that sense a Stirling engine is a cryo-cooler. In converting heat into work the engine creates an absence of heat, which we sense as "cold". Heat being conducted, we understand, convection, radiation, are understandable intuitively. Heat simply disappearing and leaving cold is not a phenomenon we are familiar with in life. Heat converted into Work is no longer heat but cold, the absence of heat. So efforts to trace the heat as it passes through the engine are liable to result in confusion. I don't know what you mean exactly by "expansion space". I have no idea what you mean by "the diaphragm creates the expansion space by deflection." As far as this statement: "Either way work must be done against the atmouspheric pressure. And either way each drives the crank via what I would call a push rod." It is entirely wrong. The displacer does not drive the crank. The displacer is not a power piston or diaphragm. I did not intend this thread to be a course on how a Stirling engine works, I assume if people are interested they would research the subject. But I'll try to clarify things if I can. But it seems you are thinking of a power piston or diaphragm that drives a crankshaft. The function of a displacer is not to drive the crankshaft. It does not drive the crankshaft. It does not do work against atmospheric pressure. Basically the displacer is a kind of valve that allows heat into the engine in metered bursts. Heat enters the engine through the hot plate or hot heat exchanger, but not while the displacer is blocking the heat from entering. The displacer is, rather than a valve, it is more like an umbrella used for shade, to block the heat of the sun. When the displacer moves out of the way temporarily, some radiant heat is allowed into the engine, expanding the gas to do work. When the gas has used up it's energy performing work, the displacer moves out of the way again, allowing in another burst of heat for another cycle. In that sense the displacer serves the same function as the spark plugs which ignites that fuel mixture in an internal combustion engine to deliver heat.

In relocating the thread, an edit to the previous post was lost apparently. I had added: The 20% represents the potential drop in temperature for a "perfect engine" with no friction or other losses, in which case the working fluid heated to 212F can at the absolute maximum be brought down to the ambient temperature of 85F, not by rejecting heat to the sink, but by conversion of that heat to work. Below that point and heat would have to flow from the sink back into the engine. The remaining 80% represents the remaining heat, which if it could be utilized by the engine to produce work would bring the temperature of the working fluid down the rest of the way to absolute zero. My contention is, at or below the point of equalization, which in this case is 85F, no "heating the cold plate and the reservoir it's coupled to" is actually possible as this would require heat to flow across an equilibrium and simultaneously reduce the temperature of the engine to zero Kelvin, all in an instant. If that were to happen the engine would implode becoming a Bose-Einstein condensate or some such thing.

That's fine. But can we please preserve a link to the continuation of this discussion, for anyone having followed it this far? https://www.scienceforums.net/topic/122721-heat-engine-experiments-and-2nd-law-of-thermodynamics/#comments

That would be the conventional viewpoint. My hands on experience indicates otherwise. With the engine running on scalding hot water poured into a vacuum flask to prevent incidental heat loss, the cold plate remained cold. Then blocking the cold plate so heat could not escape to the reservoir, the plate, apparently became colder, though other possible explanations have been offered. As I said, I need to aquire some temperature probes to get an objective measure as I may simply be seeing what I want to see. If I fail to respond to any additional comments, I'm not ignoring them. This thread is moving too fast for me to keep up with and I need a break. I am very busy working on the house, pouring a new concrete foundation between posts. I will have to catch up here when that project is completed. I also have additional modifications to make and more engines to build and supplies to pick up, like the probes. Without proper "control" engines and such, and basic measuring equipment, discussing the "results" of experiments is inconclusive at best. I apologize for the interlude but I will be back. Many thanks to everyone for all the input, and feel free to carry on the conversation in my temporary absence. I'll catch up when I'm not so overloaded by other responsibilities.

That is true, I apologize for any confusion, there were several different experiments, but a few posts back I suggested we focus on just my first experiment, where I ran the engine on hot water, then covered the sink or cold heat exchanger in an effort to block the "rejection" of heat to the sink. That post where I suggested focusing on that one experiment to begin with is linked above. My purpose is to report on the results of some experiments. I don't have questions about thermodynamics, though I welcome any suggestions regarding how the experiments might be improved. I have ideas about how Stirling heat engines work, from my personal experience in building them and doing independent research, which may be right or wrong, but which seems contrary to accepted theory. I predicted ten years ago that covering the cold plate of the engine would make the engine run better and improve efficiency which everyone I knew on the Stirling engine forum thought was preposterous. I wrote: "If more heat is extracted as work than what actually reaches the heat sink, then theoretically, insulating the cold end of the displacer chamber against the external ambient temperatures would improve engine efficiency." A few days ago I received my model Stirling engine in the mail and finally got around to running the actual experiment. The results were as predicted, which actually surprised me greatly. Generally, a theory that accurately predicts experimental results carries some weight in science, usually. But I'm not insisting my theory is correct. There may be other explanations, but my main intention is to simply put the results of the experiments out there and get some feedback.

I've highlighted some statements here that are incorrect, or perhaps are using inapplicable terminology, that at any rate doesn't reflect the actual structure or operation of these engines. First of all, there is no diaphragm. I'm not sure what you assume to be, or are referring to as a "diaphragm". It is a piston engine. The large disk is not a diaphragm or piston but a "displacer". The displacer does not do any work "against atmospheric pressure", if by chance, by "diaphragm" you are actually referring to the displacer, which does not itself do any actual or appreciable work whatsoever. The engine does no work to expand and contract the volume of the working fluid. Heat itself, the heat applied to the engine effects expansion of the air trapped inside the engine. Heat expands the gas, or causes the gas to expand. The expansion of the gas drives out the piston which by means of a connecting rod, turns the crank. The "WORK", is performed by the expanding gas which is expanding due to the application of heat. "Working fluid", I believe, refers to the fact that the heated and expanding gas is what is "working" doing the work of driving the piston which in turn drives the entire machine along with any load. All of the work performed is performed by the expansion of the gas, or by atmospheric pressure after the gas spends it's heat energy and becomes cold. The displacer does virtually no work, rather it simply controls the intake of heat to the engine by periodically uncovering the hot plate heat exchanger. What moves the displacers position is again, the heat, expanding the gas and driving the piston which turns the crankshaft which controls the positioning of the displacer which brings the air or "working fluid" into periodic contact with the hot plate. There is no diaphragm. The Carnot heat engine efficiency formula does not take into account "work". Carnot had no concept of heat being converted into work. Nevertheless, the formula is still used and treated as accurate. (Just for the record, that does not reflect my own personal opinion). My personal opinion is that Carnot had no actual familiarity with how engines actually work. His Carnot engine, which is supposed to be "the most efficient heat engine possible", is an intellectual abstraction with no real world functionality, It is not "efficient". It's effective work capacity is zero. It requires outside assistance just to be moved from one reservoir to another and back, and outside assistance to apply weights and such, I have difficulty imagining how or why anyone ever took it seriously, never mind considering it "the most efficient engine possible". It's efficiency for converting heat into work is, taking a look at it myself, as an engine mechanic, exactly zero. It's completely non-functioning! The "science" of thermodynamics today, resembles a hodge podge of obsoleted nonsense. Hardly anyone alive today has any real practical knowledge of the actual inner workings and functionality of Stirling heat engines, and those who think they know are mostly wrong.

The experiment in question is an engine running on boiling hot water, not ice, in an ambient environment at 85F. Let's not confuse things beyond what is necessary and treat one example at a time. Why? how can it? Heat flows from hot to cold. In a Stirling engine the working gas is sealed in the engine. Heat cannot just be exhausted as in an internal combustion engine. If the temperatures are equal there is no heat flow from hot to cold as there is no hot or cold. Heat engine efficiency is a mathematical calculation based on the formula Th - Tc / Th. at the temperatures in this experiment, that works out to 18.9% That maximum efficiency represents the point where heat is converted into work, bringing the temperature down to Tc. Tc is the temperature of the sink. It can't just be asserted that an 18.9% efficient engine is 100% efficient. heat flow cannot continue where the "heat rejection temperature" is equivalent to the sink. It is two different heat scales being conflated.

Let's try this. In my experiment using boiling water (212F) at ambient temperature (85F), "maximum efficiency" can be calculated to be 18.9% if the engine "rejects heat" at a temperature of 85F. That is, it would have to extract enough work to bring the input temperature of 212F down to 85F output temperature. But, heat cannot be "rejected" at a temperature equivalent to the sink. Setting that fact aside for the moment we have the fact that my engine only needs to have a Carnot efficiency of 18.9% (not 100%) to no longer have a condition where heat is being "rejected". At 18.9% efficiency heat is no longer being rejected. Temperatures are equivalent, so no "flow" can result. An efficiency of a mere 19% would have heat flowing backward from the ambient sink back into the engine. Therefore, to say the engine must reject heat because no engine is 100% efficient is apples to oranges. It is not necessary to have 100% efficiency on an absolute scale, or bring the temperature down to absolute zero, rejection to the sink ceases at any efficiency >= 18.9%

My point is that for an engine to be 100% Carnot efficiency it would have to cool the working fluid down to an impossible 0 K not Tc.

Not really. The formula for heat engine efficiency is: Th - Tc / Th. On a scale that begins at absolute zero. So if a heat engine reduces the temperature of the heat from T-hot down to T-cold that is simply the percentage of cooling produced on the absolute temperature scale, or how far the engine has cooled the "working fluid" on the way down to absolute zero. It simply states that at best, the engine cannot reduce the temperature any lower than Tc. It derived from Carnot who conceived the "flow of caloric" as including all that caloric down to the absolute zero temperature. The "rejected" heat is the un-utilized percentage of caloric below Tc down to absolute zero, which Carnot conceived as also flowing through the engine. That is the actual original basis of this engine efficiency formula. That is, of course, my understanding after some rather extensive reading and research on the subject. So this "maximum efficiency" represents a potential for heat reduction or energy conversion which (theoretically), bottoms out at Tc.

Recognizing this, I have put the word flow in air quotes. Thank you Bufofrog for that clarification. So can we all agree that "flow" is a figurative expression, that in this context refers to energy transfer?

Let's look at this statement: "no conversion of heat to work will be 100% efficient." What does that actually mean in real terms? Can we agree that if the temperature of a heat engine is equal to the temperature of the surroundings, no heat will "flow" into the engine? Also, if the temperature of the heat engine is the same as the surrounding ambient temperature, then no heat will "flow" out of the engine?

I don't. The moderator that banned me from the other forum made that assertion. The experiment was intended to determine what would happen if the path to the cold "reservoir" were blocked by insulation. Internally the engine still maintains a temperature difference. However, I really need to repeat the experiment with some temperature probes to determine objectively what is actually going on. My supposition is that, observing an increase in RPM with the cold sink shielded, the likely explanation is that, internally, the cold side of the engine became incrementally cooler as a consequence of protecting the engine from backward heat flow from the sink. That is a given. I don't believe I ever suggested otherwise. How is this against the rules? The material I've linked to is relevant and open to discussion. It is not spam or advertising. Not off topic. I've read everything you've posted or linked to. Was there something specific you wanted me to respond to? That presentation is just an example. The assertion made that a heat engine can only avoid dumping unused heat to the sink by converting ALL the energy that exists, down to absolute zero is a universally repeated dictum in modern thermodynamics, and the Crux of the issue the experiment was intended to address. The statement made in that video is presented as an absolute, unquestionable truth or law of nature, and typical of any and all such presentations I've ever seen, and I've read and seen a lot. But how can that be true when quite obviously, not only would heat flow to the sink stop, when the cold heat exchanger equalized with the ambient, heat would flow into the engine from ambient as soon as the engine got any colder. The flow to the sink would stop when the cold side reached ambient (85F or approximately 302 Kelvin) not absolute zero I have provided absolutely every detail, as you have already said, to the point of going "overboard in describing". I simply took a Stirling engine and blocked heat flow to the sink with insulation, to determine if such heat flow is really necessary. If heat were a fluid, insulating the sink should slow or stop the engine cold. Instead the engine began running faster. If heat is kinetic energy, then such "fluid flow" to the sink should be no more necessary than a baseball hit with a bat requires a "cold sink" to "flow" to the bleachers. Kinetic energy, generally, does not flow from high to low or hot to cold like a fluid, it propagates through collisions. A Stirling engine operates by marshaling the kinetic energy of billions of energetic air or gas molecules to collide with a piston. The collisions reduce the kinetic energy of the gas, transferring that energy to the piston. A gas molecule with a lot of energy is "hot". A gas molecule with little energy after a collision, having transfered the energy to a piston is "cold". A Stirling heat engine converts heat into work, by providing a moveable piston for the hot gasses to collide with. Something to transfer their kinetic energy to. Carnot's concept of the caloric seems to be pure mythology. Why any "fluid flow" through a heat engine as some kind of absolutely unavoidable necessity is still adhered to in any branch of modern science is beyond me. This simple experiment appears to demonstrate that this "flow" of "fluid" through a heat engine is a fallacy.

Of course. Possibly.

I provided video ("worth a thousand words"). The engine is an unmodified (model JAJ 838 KIT) ordered here: https://www.stirlinghobbyshop.com/english/stirling-engine-solar-ltd-low-temperature-stirling-engine-ltd-stirling/ltd-stirling-engine-ja-828/#cc-m-product-9759217783 stock engine, except for replacing the steel bolts with nylon bolts to minimize parasitic heat loss. A comon practice with Stirling engine model builders. Hot water from the teapot about 212F presumably. It had just boiled The ambient room temperature was approximately 85F. Insulation consisted of Corning fiberglass, styrofoam packing the engine was shipped with, and on top, 1/4 inch foil face styrofoam "house wrap". Before placing the 1/4 inch foil faced styrofoam over the "sink" the RPM of the engine was a steady 162 RPM. Immediately after completely securing the top disk of styrofoam, the RPM climbed to 180 RPM and remained there for several hours. This is a very simple and straightforward experiment. I'm at a loss to imagine what more I could add that isn't already completely transparent. This is one typical course in thermodynamics: These engines are virtually hermetically sealed. The "working fluid" itself is entirely retained in the engine not thrown away or continually replaced in any way. Part Ii I cannot agree with this presentation because, if the engine were to convert enough heat into work to simply reduce the temperature 1 degree below ambient, heat would begin flowing backward. Heat always flows from hot to cold. In a room at 85 degrees F, that would mean the engine would only need to bring the temperature down from 212 F to 84 F by means of conversion to work, for the heat to begin reversing direction. (Not as presented, down to an impossible 0Kelvin or absolute zero where mater as we know it ceases to exist.)

At this point, the focus of the discussion is, though the caloric theory is recognized as obsolete, there is a persistent remnant stated in a somewhat vague way in courses on thermodynamics that some heat must always be rejected to the sink in a heat engine. My insulation is not perfect, so indeed, it is within the realm of possibility that "some" heat is still getting through, but if the functionality of a heat engine depends in any way on such "flowing through" of heat, then insulating the sink is roughly equivalent to stuffing a potato in the tailpipe of a car. Or shutting off the outlet in the water turbine of Niagra falls. The. Expected result SHOULD BE, if flow through of heat is a functional necessity of the engine; a slowing down or stopping of the engine should be observed. We are not talking about MY engine at this point, the focus is just a stock model "off the shelf" Stirling engine readily available from several internet markets. We are talking about expected results of an experiment. How can it be explained that blocking the path of heat flow to the sink to any degree results in higher RPM and a longer run on a finite heat source? In this case a vacuum flask containing hot water. My story is just some background. The topic is the experiment. The results suggest there may be something wrong with the general "flow through" theory of heat engine operation. If not, why not? It seems a peculiar result, does it not? My supposition is that since a Stirling engine's efficiency increases with increased temperature differential, blocking the so-called "sink" in some way increases the temperature difference. My tentative explanation is that contrary to popular opinion, a Stirling heat engine does not actually always reject heat to the sink, but rather, under some circumstances; infiltration of heat into the engine (in reverse) through the sink reduces the temperature difference that the engine itself is maintaining by converting incoming heat from the source into "work", including momentum and then using that momentum for cooling by expansion, which brings the cold side temperature down below ambient. So an engine with an insulated cold side runs better by blocking reverse heat flow. For now the focus is on this experiment: Heat is delivered into the engine through the bottom. I then insulated the sides and replaced the bolts in an effort to minimize loses, so the heat can only escape the Dewar by passing into the engine and up and presumably out through the top, That way most of the heat must pass into or through the "working fluid". Now insulating the top, should block the flow of heat, causing a slow down, logically, shouldn't it? But it doesn't. Instead, my friend and I using a stop watch and counting the revolutions, fount that the engine ran at an RPM of +18 with the top insulated. The RPM increased by 18 revolutions per minute.

To offer some context: growing up in the country there was always machinery breaking down which was very expensive to get repaired all the time, so in 10th grade (high school) my dad suggested I enroll in a vocational course for engine repair. There was some basic theory, but mostly we just tore down and rebuilt engines all day. After graduation I opened a repair shop out of my parents garage, then spent most of my life working in engine repair shops Fast forward to about 20 years ago, I was asked to help with designing a solar Stirling engine for a semi retired government contractor. I worked hard on this because it seemed like a big opportunity at the time, and I came up with what I thought was a great design that exceeded specifications. He ran it past some associates in, I think, the Dept. of Energy and their verdict was that it was impossible because it violated the second law of thermodynamics. So, instead of a plane ticket to California and a lucrative job, I was left with a rejected plan for a Stirling type heat engine. So, not knowing the reason why my design was supposed to be "impossible" and in violation of some law of physics I never heard of I casually began doing research on the subject in my spare time as a kind of hobby. Carnot's theorem was, as far as I know, the earliest formulation of the second law: https://en.m.wikipedia.org/wiki/Carnot's_theorem_(thermodynamics) Derived from the Caloric Theory of heat: https://en.m.wikipedia.org/wiki/Caloric_theory After that we have Clausius, Lord Kelvin (William Thompson) etc. This Second law (specifically as it is supposed to apply to heat engines) has gone through so many iterations I am not really able to pin down exactly what it is supposed to be saying. But, the long and short of it is that my engine design was a fusion of a Stirling engine and an air cycle heat pump. It did not use solar directly, but rather drew in atmospheric air to run through a compression/expansion refrigeration cycle which would produce the temperature difference to power the Stirling engine. As a combined machine, it had few moving parts and several shared functions. The thing that seems to have gotten under someone's craw was that it ran on "one reservoir", or a single heat source. Solar heated warm air, directly from the atmosphere. Such a thing has been declared "impossible" at various times in various ways, all such statements having been wrapped up together as valid statements of the second law. Specifically, this second law, in its early formulations seems very slippery, and I don't have a clear picture as to, does it apply to this "open system" or not. Now that I have some finances available, I've just gone and purchased six model engines to run some common sense tests and experiments to see if, in principle, my engine design is impossible or not. The first order of business, I thought, should be to settle this Caloric theory that a heat engine works by heat flowing through it from a hot reservoir THROUGH to a cold reservoir. Blocking the path or outlet from the engine is, according to Carnot's theory equivalent to stopping up the outlet of a fluid turbine. Without an outlet for the heat, according to Carnot, the engine should quit. In my experiment however, insulating the path or outlet of the model Stirling engine had the opposite result. The engine, rather than overheating and stopping or something, ran measurably faster and longer.

This is a continuation of another thread (kind of): https://www.scienceforums.net/topic/46143-stirling-turbine/?tab=comments#comment-1148735 but it is also something of a fresh start. So, I'm here starting a new thread To get right into it, I purchased several identical Stirling engines from https://www.stirlinghobbyshop.com/ that is not a promotion, just a fact. What I liked about these were they came in kit form, so I could do various modifications. The first modification was simply to cut down on heat loss by replacing the steel bolts that came with the engine with nylon bolts, and also to add insulation where necessary, and to use a vacuum insulated flask, basically to minimize all heat transfers as much as possible, other than heat transfer through the working fluid (air) inside the engine. This was the first test, which I had been thinking about for years. I first mentioned the idea on the Stirling Engine forum back in the year 2010: https://stirlingengineforum.com/viewtopic.php?f=1&t=478 I wrote (edited for length) Nobody agreed with this. Everyone tried to educate me about how a Stirling engine works. The sink is colder than the engine. Heat flows from the engine to the sink. Nobody seemed interested in running such an experiment. Now, my observation of Stirling engines over the years, mostly on YouTube, seemed to show that at least some Stirling engines converted ALL the heat, not transferring any to the sink. This was mainly due to seeing an engine which someone discovered could run quite well without a flywheel. There are several other examples that can be found. My reasoning was that the engine was moving too fast to "sink heat" by conduction so as to cause the piston to return "on its own" without the stored momentum in a flywheel to push it back down the cylinder. It seemed to me that if ALL the heat added in one cycle were not used up (converted to work) then the piston would not be able to return against the remaining hot expanding gas, without help from the flywheel. My reading of old thermodynamics books and books on liquifying gases and such also had me convinced that when a gas expands and does work in a cylinder driving a piston, very cold temperatures can result, potentially, much colder than ambient. So the first thing I did when I got one of my kits together was to run this experiment: The engine is running on scalding hot water from the tea kettle, but without the steel bolts to conduct heat, the top of the engine felt- room temperature. The heat could be going either way. I really had expected, probably everybody was right and insulating the sink would quickly bring the engine to a stop. But it did not stop. After it recovered from the insulation rubbing on the flywheel, it actually ran, by my friends stopwatch, about 18 RPM faster, and it also ran in this condition, with the sink insulated, about an hour longer than it ran previously without the insulation. Certainly I could not be the only one in the past century to notice these things, or do some such experiment, right? So I did more experiments with the engine using ice. It took 33 hours before the engine stopped running as the ice had all melted. Repeating the experiment with an identical vacuum flask full of a solid cylinder of ice, but not starting the engine; this time the engine quit running and the ice had all melted five hours sooner. Apparently, the engine running, actively converting the incoming ambient heat to "work" meant less heat reached the ice, so the ice took five hours longer to melt, and the engine continued running for those additional five hours. In fact I got so tired of the engine not stopping I added a piece of aluminum on top from an old appliance electric outlet box to draw down more heat. Now both of these outcomes were predicted based on basic thermodynamics principles, but the moderators on the other forum said such a result would be "perpetual motion" and "a violation of the second law of thermodynamics", locked the thread and banned me from the forum for "invoking perpetual motion". I tried to point out that these were stock model Stirling engines and that I was not advocating perpetual motion, l just ran the experiments because, as far as I could find, no one else ever did before. And obviously these TOY engines were not anywhere near 100% efficient and in all cases did stop running eventually, but I was banned anyway. More detailed descriptions are uploaded to a YouTube playlist: That basic theory I'm developing to explain these results is that the Carnot mathematical limit for a heat engine efficiency, between the two reservoirs, is based on the fact that if the engine were to produce cold lower in temperature than the sink, heat flows back into the engine from the sink which directly limits how cold the engine can get and therefore it's maximum theoretical efficiency. But in reality, the engine can expand the gas to the point where it may be colder than the "sink", in which case, insulating the sink, thereby blocking backward heat infiltration into the engine can allow it to run better, faster, longer. The engine will still use up the heat, and the temperatures will equalize and the engine will stop running, at least in the case of added heat. With cold applied, below ambient, the heat comes from the atmosphere, heated by the sun, which heat may take a little longer to exhaust. But no insulation is perfect, so the ice still melts. Could the second law of thermodynamics be a result of not making complete observations by neglecting to conducting such simple experiments? I haven't come to any hard conclusions at this point. I have many additional modifications to make and many more experiments to run, but the results are such that at this point I would already like some comments and feedback. Please!

On second thought, a 9 degree change on the C scale is more like 15 on the F. That seems a bit more significant somehow. Especially when taking into account the humidity factor along with the possible cumulative effect of repeated iterations in a running engine addressed above, it seems to me that the cooling effect could be quite pronounced. This video helps to explain the process of "Throttling" and why it results in cooling. Essentially kinetic energy is reduced and potential energy is increased as the air molecules are drawn further and further apart.

If this is the case, such a slight drop in temperature seems rather insignificant. There may be another factor involved though: Humidity. I came across this discussion while looking up random references to Joule-Thompson Effect. http://www.clubfrontier.org/forums/f11/throttle-body-icing-74415/ It seems that under certain conditions automotive carburetors can ice up at the throttle due to Joule-Thompson Effect resulting in a run away engine - even under the hood where temperatures are rather hot. The result being that some manufacturers have installed heaters to circumvent the problem. One commentator on that thread states: "Carb icing isn't really a hot or cold weather issue, but rather a humidity/dew point issue. so keep in mind that as air flows thru the venturi part of the throttle body, there is a drastic localized drop in temperature that goes along with the drop in pressure." The line along which I'm thinking at this point is that although the temperature drop might be initially rather slight. Just a few degrees, the effect, as the engine continues to operate drawing more and more air through the valve, the effect might be cumulative. That is, a few degrees of localized cooling with the first stroke of the piston, a few more degrees with the second stroke, a few more with the third etc. until the cooling effect becomes significant. In other words, not just the air gets cold but also the valve itself along with all the surrounding metal in the vicinity of the valve, the valve housing, cylinder, top of the piston etc. which might get progressively colder the longer the engine runs. Correspondingly the air entering through the valve would tend to have more and more heat drawn out of it with each cycle. If the temperature drop were only .5 (1/2) degree per cycle, what might it be after 1 minute of operation in an engine running at say 500 RPM ? This is, of course, mere speculation, but if a carburetor in a car engine, under the hood, in a relatively hot environment with what could conceivably only be a very slight pressure drop at the throttle could freeze up the entire throttle body I would assume this would have to be due to a cumulative effect in a running engine. The temperature drop with each cycle might be nearly imperceptible but the cumulative effect over time could be significant. So, was I hoping for more of a change? I suppose. I'm mostly just trying to find some logical explanation for how this so-called "compressor" could operate as described in the patent. I would tend to simply dismiss the whole thing as manifestly impossible, if not for the fact that in an interview with the inventors son, he stated that his father did indeed have a working prototype as well as a small working model which he saw operating when he accompanied his father to the patent office. This Wiki reference was also cited in that thread: http://en.wikipedia.org/wiki/Carburetor_icing What I'm getting at is that in most scientific discussions about Joule-Thompson, such as you have cited above from "Chemical Thermodynamics" the discussion is limited to a strictly one time event. That is, air being passed through some throttling device from one chamber to another where there is no possibility for any cumulative effect as might be seen in a running machine where the air flows through the valve continuously or repeatedly in quick succession.

This would be true. However this so-called "compressor", according to the patent, does not use high pressure compression. Supposedly the air is still at atmospheric pressure AFTER "compression". In other words, it seems, according to the patent that the compressor does not really compressing the air much at all. It mentions that the air, after being delivered to the tank is below freezing. Electric heaters are used to heat the air from the tank for use to run an air motor. The implication, though this is not explicitly stated in the patent, is that the air is being reduced in volume by cooling rather than compression. Water cooling could conceivably bring the temperature down to somewhere above freezing I would suspect, but some additional cooling would have to come from somewhere to get it down below freezing. This "throttling valve" is all I've been able to find that looks like it might have some potential to do that. At any rate, the patent does explicitly state that the pressure does not go above about 15 psi or atmospheric pressure.