Electricity from ambient heat

Discussion in 'Physics & Math' started by Frencheneesz, Oct 3, 2008.

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  1. Tom Booth Registered Member

    My understanding of Tesla's idea is that in a Heat Engine where heat is being converted to another form of energy such as electricity, the LOAD serves as an effective Heat Sink. At least in part, so that the actual Cold sink does not receive the heat energy diverted to or absorbed by the load.

    This seems to be confirmed by various sources and/or observations made of actual Stirling Engines currently in use.

    For example, I have read in regard to Solar powered Stirlings in Utility power production from several sources that if the Load on the engine drops, due to less consumption from customers on the grid, there is a danger of the engine(s) overheating due to the heat not being withdrawn by the load.

    This seems counter-intuitive. That any engine would run cooler and more efficiently with a load than without one. However this seems to be the case.

    A few references:


    From the operating instructions of a Stirling Engine from VITA (VOLUNTEERS IN TECHNICAL ASSISTANCE - 1600 Wilson Boulevard, Suite 500, Arlington, Virginia 22209 USA)

    The wording is somewhat ambiguous but this last reference seems to be saying that the engine "grows stronger" as the load is applied and gradually increased. A gradual increase in the load results in more torque and power and the engine runs cooler and more efficiently.

    These are not the only two sources, I've come across this again and again.

    The more "Work" the heat engine performs, the more heat is converted allowing the engine to run cooler. In some cases, such as the Free Piston Stirling, without a load it can not run at all.

    So it would appear that in a heat engine, the load will, to one degree or another, serve as an effective or supplemental "heat sink", for all intents and purposes.

    What I think this boils down to is that if an "Ambient Heat Engine" has any chance of operating at all, It could not do so without a load.

    You could not have such an engine that just ran on Ambient heat. Whatever power it produced would be consumed for cooling and with loses and inefficiencies, this could not go on for long if at all.

    But with a load, you have some of the heat being carried out or away from the system. In effect, the load becomes a secondary heat sink.

    I don't really know how else to explain a heat engine running cooler and more efficiently with a load than without one.

    I don't really know about the LED issue as it is new to me but it would seem that here also, the load is drawing off heat and converting it to another form.

    If ultimately the Sun is your heat source and outer space is your sink, then the only way to have an ambient heat engine would be to make it easier for the heat in the atmosphere to escape by passing through the engine and into some load and finally into space. Easier than simply radiating into space directly from the atmosphere.

    Imagine for example if your load were a Laser beaming light into outer space.

    Heat would be able to flow from the atmosphere through the engine into space Faster and easier than if it had to slowly migrate outwards through the atmosphere.

    If such an engine were connected to a load, (The electric grid) then it too would be powering various heat sources that would be sending infrared light out into space, Heaters, Light bulbs, Toasters, Ranges, street lights, etc. etc.

    "entropy" would not be violated so long as the loads on the grid were dissipating heat into space faster than the atmosphere itself, at ground level, would be capable of doing, slowly migrating through the air.

    Perhaps this is why the LED thing works because light from the LED can get farther out into the upper atmosphere faster, even if it is only to the ceiling of the room it's in. The Heat/Energy can get to the sink (space) faster by converting into light.

    To some degree, heat energy could also be "locked up" by the loads as kinetic energy, work, momentum, etc.

    The point is, if we think of heat flowing through a heat engine like a river, than confining ourselves to the engine as our "System" the general flow of energy can be diverted to an external load which could serve as the ultimate "heat sink" for the System. The "river" once gotten flowing by "digging a cold hole" could then be diverted into the load.

    In other words, you would need to trap the heat behind a lot of insulation so that it had no way to escape to outer space without first passing through the engine and into the load.
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  3. Tom Booth Registered Member



    There is some danger of basing any assumptions on any text from a patent application as anyone can be under a misconception and apply for a patent based on such, but there are additional texts including those from general Thermodynamics, gas liquefaction, cryogenics etc. where external work performed is used to siphon off heat from a system.

    In a cryogenic cooler for example, a load is applied to an expansion turbine to carry off the heat in order to achieve very cold temperatures. A similar process using an expansion turbine is used in Gas Liquefaction. The load on the turbine is used to dump excess heat to reach very cold temperatures.

    Tesla in his article makes reference to the same - the liquefaction of gas etc. as proof of his concept, as far as such technology had been advanced in his day. Modern methods of using a load on an expansion turbine to effectively "sink" heat and achieve extremely cold temperatures was unknown in his day.
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  5. Tom Booth Registered Member

    I originally got interested in the concept of an Ambient Heat Engine by a kind of accident.

    I was simply trying to design a more efficient solar powered Stirling engine making use of a parabolic dish reflector to concentrate the suns heat on the engine.

    The idea was to come up with a design that would reduce the size of the dish to a minimum while still producing enough power for a residence so that someone could set one of these in their back yard like a satellite dish.

    A friend in California proposed the idea. Knowing I knew quite a bit about Stirling engines he related his plan to me and I began working on it.

    I went through dozens of different configurations. I wanted this to be as environmentally friendly as possible so when it came to incorporating a cooling system into the design I started looking into the "Air Cycle System" which uses plain air as a refrigerant.

    This seemed to be a perfect mach for the Stirling "Hot Air" engine.

    Since Air was being used throughout both systems, I found that there were various ways of combining the two systems to reduce the number of moving parts and increase efficiency. Also, it became possible to reclaim "waste heat" with relative ease.

    Eventually I hit upon a design which, upon running the engine in my imagination, It seemed that it was drawing in ambient heat or indirect solar energy from the air and using the heat derived to power both engine and cooling system. In other words, it continued running even after the sun went down utilizing the heat stored in the atmospheric "solar collector" and the size of the parabolic dish was reduced to zero.

    This seemed "impossible" but as I continued running the engine in my mind, I could not find any point of failure that would prevent it from working. I was not even aware of Tesla's article at the time. I only discovered that upon further researching the feasibility of the engine. What I had come up with seemed to meet Tesla's description and this encouraged me.

    Here is the basic idea.

    As Tesla pointed out, to get the engine started would require creating an initial temperature differential. This could be accomplished in a number of ways and is not particularly relevant.

    The engine, once set in motion wold use a Stirling Engine Type displacer to create a pressure differential from the temperature differential. That is, the air in the displacer chamber would be alternately heated and cooled due to the movement of the displacer. This would cause the air or gas in the chamber to alternately expand and contract.

    This would be where the resemblance to a conventional Stirling Engine would end.

    Rather than having the expanding and contracting air drive a piston, the chamber could be equipped with check valves so that as the air contracted, Ambient air would be drawn in and retained. Then as this air was heated, some of the air in the chamber would be forced out another check valve.

    The effect would be a Stirling Engine type displacer chamber acting as a pneumatic air pump or compressor.

    As has been pointed out here, air when compressed heats up.

    The ambient air thus drawn in and compressed would heat up to some degree above ambient.

    If the air were then released back to atmosphere it would return to the original temperature, but if it were cooled (back down to ambient) before being released it would get colder than ambient.

    Further, if it were first compressed, then cooled, then released through a nozzle and allowed to expand through an expansion turbine with a load attached to the turbine, the air thus compressed and released and made to do additional work while expanding through the turbine would drop in temperature precipitously, as additional heat would be diverted to the load on the turbine.

    This is, in essence, how an Air-Cycle Cryo-cooler reaches such cold temperatures, by first compressing a gas, driving off the heat (cooling the compressed gas back down to ambient) then releasing the gas through a turbine with a load to cause it to do work as it expands and so give up its latent heat.

    Pressure, or the energy represented by pressure is in actuality latent heat energy. When a pressurized gas is released and allowed to expand through a turbine to do work, the latent heat energy or internal kinetic energy represented by pressure is converted to work to power the load on the turbine. If the pressurized gas has been cooled to Ambient before it is released through the turbine, it then drops in temperature far below ambient.

    It should be pointed out that moving a displacer back and forth in a displacer chamber takes a very miniscule amount of mechanical input. In fact a displacer can be suspended in a magnetic field rendering it virtually weightless. This is the sole mechanical energy input to the system. All other energy input is from Ambient.

    The temperature differential between the hot compressed air and the "supercooled" air leaving the turbine is what drives the "compressor"

    The heat accumulated, or rather the internal heat, represented by the pressure developed, if the system is well insulated, has nowhere to go but to the load on the turbine.

    Probably there is something I'm overlooking here, but here is a animated model of the proposed engine showing its components and how they would interact:

    Please Register or Log in to view the hidden image!

    This is an exploded view so that all components are visible not necessarily what the engine would look like.

    Also something other than a solenoid might be used to drive the displacer.

    Note: "Insolation" = Insulation, A spelling error. I didn't notice and not feel like going through all those frames of the animation to fix.
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  7. Aqueous Id flat Earth skeptic Valued Senior Member


    Here are some of your mistakes.

    Load = energy sink

    No, the load does not sink the energy. Think about what that means. To be either hotter or colder than ambient is to be in a condition of higher potential difference. This is why energy can neither be created nor destroyed. A higher potential difference can not be created. You can not "create" cold (a sink) any more than you can "create" heat (a source). For the same reason a load can cannot create a sink anymore than it can not create a source. Just as the exhaust pressure in an internal combustion engine can not be used to raise the cylinder pressure, you can not take the exhaust pressure, and turn a turbine that produces a vacuum in the cylinder on the return stroke. For the same reason, you can not take the load a light bulb presents to an electrical circuit and then drive a photocell that powers the light. And so on. All of these are "over unity" and therefore impossible.

    Note, if there was an iota of possibility in creating a sink from the load, there would be free energy in use today all over the world and we'd all be living for free.

    Stirling engine heats/loses power unloaded

    I think you misunderstand the way energy, temperature and pressure in the Stirling engine relate to work. It's completely wrong to assume that the load is acting as a sink. The greater the sink, or, to be more accurate, the lower the sink temperature, the greater the compression in the piston. Adding load does nothing to lower the sink temperature below ambient. To do that you need a better heat exchanger and/or lower cold operating temperature. This is the wall that makes a "high side ambient" Stirling engine pretty useless.

    When the engine is unloaded, there will be more heat delivered to the cold side, heat that was set aside (in the design) to be used for work. If not designed to accommodate this extra heat, a bottleneck will occur at the cold side. It will run warmer, and the engine can no longer run optimally until an adustment is made to lower the cold side temp. This is because as long as there is an inadequate temperature differential, you're running sub-optimally. Normally a larger heat sink (meaning the device) can cure this. In short, the engines that need to be loaded are likely suffering from paring back on the size of the heat sink device, for cost reasons, in which the heatsink provided is not designed to eliminate the bottle neck.

    Once a load is applied, less heat is delivered to the cold side, and gradually it cools down to peak cold operating temperature and the engine "runs strong" again.

    Solar powered Stirling engine overheats

    The supposed issue with a solar powered Stirling engine overheating is silly. What does that even mean? That the engine is not designed to handle the maximum amount of light that can been focused onto it? Then redesign the engine or regulate the amount light. The latter is a piece of cake. In any case, the only reason for abnormally high operating temperature is the same as above.

    Obviously an engine running on the difference between ambient and a cold source would never have an overheating problem. It can run with plastic parts. Pistons and cylinders could be made out of Teflon.

    Outer space can work as an energy sink

    Here you've left the normal mode of heat transfer (conduction and convection through air for example) to a system that relies entirely on radiation. In any case, there would be normally be no point in putting a Stirling engine in space.

    Now that's just plain silly. Ambient heat radiates off the upper atmosphere continuously. Imagining that you could place a radiator in orbit, then use it a a better heat sink than one you have access to on earth is nonsensical.

    Again, this is simply silly. In the first place, there's no shortage of ways to waste energy on earth. But this is nutty.

    No, the laser doesn't propagate as heat but as coherent light. As you might imagine, it doesn't matter where you aim the laser, it's going to waste the same amount of power whether it's aimed at the sky or used to do something useful.
    So far all you are proposing to do is to waste energy.
    Again, that's nonsense. You can't turn "space" into a heat sink for a ground energy source. And you can't create a potential difference by wasting energy. You can't create a space based radiator as sink to a ground based heat source. At best you could cause a potential difference in a satellite that has a hot and cold side, such as a thermocouple that faces the sun on one side and faces darkness on the cold side. Laser light is not a potential difference, so you can't harness it as such. That is, you can't cause more light to emanate out of the laser just because the target is colder.

    Evaporation/Tesla contradicts laws of thermodynamics

    From Wikipedia:

    For molecules of a liquid to evaporate, they must be located near the surface, be moving in the proper direction, and have sufficient kinetic energy to overcome liquid-phase intermolecular forces. Only a small proportion of the molecules meet these criteria, so the rate of evaporation is limited. Since the kinetic energy of a molecule is proportional to its temperature, evaporation proceeds more quickly at higher temperatures. As the faster-moving molecules escape, the remaining molecules have lower average kinetic energy, and the temperature of the liquid, thus, decreases.
  8. Tom Booth Registered Member

    So far I've built a rather crude "displacer chamber" with check valves instead of a piston to test the idea that a displacer chamber could function as an air pump or compressor.

    The check valves I made were rather crude, consisting of some ball bearings from an old skateboard balanced on the ends of some copper tubing and held more or less in place with a piece of screening.

    The "check valves" were not very air tight and were not functioning very well, but the contraption did manage to partially inflate a balloon before the check valves apparently failed.

    Here is a video of the experiment:

    calypso53.com/stirling/Stirling_Ice_Pump_2.MPG - (6.49 MB mpg)

    The idea being basically to use a temperature differential to compress ambient air to potentially charge an air-cycle cooling system or heat exchanger that would maintain the temperature differential by first using the heat generated from the compressed ambient air then dumping the excess heat back to ambient as well as using the load on the turbine as a "sink" to take out the latent heat from the compressed and cooled air to achieve a temperature well below ambient.
  9. Aqueous Id flat Earth skeptic Valued Senior Member


    I can't make sense of your sketch. You're using a solenoid to depressurize air, expecting to drive a turbo? That consumes electricity. And you hope to produce more electricity on the output?

    You're obviously hoping for a lot more than "over unity". As a starting question, let me try this: at a starting temp of 25°C, for a 1L cylinder of ambient air that expands under vacuum to 2L, what would be the temperature of the air, under ideal conditions, that the "turbogenerator" would use?
  10. Tom Booth Registered Member

    OK no problem.

    Then I'm not sure how you would explain the bird. I agree that energy cannot be created or destroyed but it can be MOVED.

    For example, I can carry a can of gasoline from one location where it is of no use to another location where it becomes useful. I can use a "heat pump" to get rid of energy to move it from a location where it is a nuisance to one where it does not effect me.

    In the case of ambient heat, it does not need to be "created" it is already there. It is a given. Latent or in potential similar to the potential energy in a can of gasoline that contains much energy but which I can move from one place to another with little energy.

    Using relatively little energy I can move much ambient heat energy out to create a sink. Yes, this is indeed "wasting" energy and lots of it. But it is getting rid of excess energy that serves no immediate purpose.

    Again, how does the bird function at all if it does not somehow "create" cold ?

    It simply "wastes" a great deal more heat than it uses. You don't "create" cold. Cold is just the relative absence of heat. You can move heat away and waste it using less energy than the heat contains in potential.

    I guess you've never heard of a turbocharger.

    I don't really agree there.

    An ambient heat engine is not going to just put itself together and start running. Such an engine would have to be designed with a clear understanding of the principles involved and the goal to be achieved. Even if theoretically possible, it may never be economically feasible. That is, whatever small amount of energy it might produce or convert may not make it worth the investment.

    True. It does not lower the temperature of the "sink". Rather it converts the heat before it reaches the sink.

    Or the load is reintroduced.

    Agreed. but why ?

    The idea of a "sink" is a place to dump the excess heat. Why should it matter if the excess energy is dumped into a sink or into a load ? The result is the same. The excess energy is eliminated from the local system.

    Possibly. On the other hand, since potential ambient heat energy can be moved or concentrated in a small area via a heat pump of one sort or another, the problem of overheating is not necessarily eliminated.

    I did not propose putting a Stirling engine in space. You must have misunderstood something.

    Ultimately all solar energy reaching the earth is radiated back into space sooner or later. Otherwise the Earth itself would quickly become unbearably hot and could not support life as we know it. Every day the earths atmosphere would get hotter and hotter having retained all the heat from one day to the next. Thankfully, the heat accumulated in the atmosphere during the day is radiated back out into space at night.

    That is a straw man argument. I never proposed any such thing as a radiator in orbit. nonsensical or not.

    Exactly ! Now we are getting somewhere.

    If you can waste enough energy quickly enough you end up with a deficit.

    A "Heat Sink" is simply that. An energy deficit.

    I beg to differ. Space is already the ultimate heat sink, it doesn't have to be "turned into" one. And I think as far as "you can't create a potential difference by wasting energy." I think the bird demonstrates just that. It "wastes" a great deal more ambient heat than it uses.

    But when you are talking about a virtually infinite heat source (Ambient heat is relatively constant and renewed by the sun on a daily basis) .01% of infinity is itself infinity.

    I'm not sure what your point is in quoting this reference.

    Are you suggesting that evaporative cooling is impossible because it contradicts the laws of thermodynamics or what exactly ?
  11. Tom Booth Registered Member

    The function of the solenoid is to shunt the displacer back and forth (or in this case up and down). Of itself it does nothing but move or "displace" air from one end of the chamber to the other (or from top to bottom and back to the top again).

    The solenoid is of no real importance, it is just one possible means of moving the displacer since this is not a typical Stirling Engine with a crankshaft and flywheel which would be the usual mechanism. Some other mechanism could be used.

    The solenoid does not drive the turbine.

    Just as a conventional Stirling Engine drives a piston, this engine uses heat or a temperature differential. A more efficient turbine has been substituted in place of the piston, otherwise the operating principle is much the same as a conventional Stirling Engine except that this engine doubles as a heat exchanger with no additional energy input.

    The basic operating principle of a Stirling Engine is that it takes less mechanical energy to move the displacer than you get back from the piston.

    The piston drives the crankshaft which drives the displacer.

    You have to basically ignore the mechanical aspects of a Stirling Engine to avoid mistaking it as some kind of "perpetual motion" and realize that the energy to run the engine is derived from the heat input not the mechanical action of the displacer, or in this case the solenoid driving the displacer.

    In fact the displacer in some Stirling engines operate without any external mechanical input whatsoever.

    Your question has no relevance in regard to the operation of this engine.

    At no point does "ambient air expand under vacuum" Also the temperature of the air driving the turbine is largely irrelevant. The turbine is driven by the velocity of the compressed air escaping the nozzle. It is pressure of the air released which potential energy (pressure) converts to kinetic (velocity) to power the turbine.

    What is important here is that a gas, in performing work has only heat energy to expend regardless of whether the work is performed by the temperature, pressure, velocity or whatever.

    The air escaping the nozzle performs work on the turbine. Because the air has been compressed and cooled to ambient it can do nothing but get colder upon performing work to turn the turbine along with the load on the turbine.

    I am not "using a solenoid to depressurize air". Or if so, this would only take place when the displacer moves the air in the chamber to the cold side to draw in additional ambient.
  12. Aqueous Id flat Earth skeptic Valued Senior Member


    You're main errors seem to be stuck on failing to understand evaporation. I gave you the description from Wikipedia to explain in the simplest terms why water cools during evaporation. The intent of giving that to you was to dispel the notion that energy is created during evaporation. What you are supposed to gain from it is the understanding that energy is conserved. A small amount of energy is depleted from the liquid, lowering its temperature, but the amount subtracted is added back to the ambient when the water vapor molecule is added to the ambient. No energy is created. A very small potential difference is generated (not created) by the natural process, and provided you can build a machine that exploits it, in this case, a dipping bird, then you are able to demonstrate the that dipping bird exploits that difference, nothing more. It doesn't demonstrate anything about creating energy.

    Your engine still makes no sense. If the piston only serves to displace the air. Where does the temperature change come from? You can't get a temperature change without compression (or suction).
  13. Tom Booth Registered Member

    I never stated, nor did I ever conceive that "energy is created during evaporation".

    I'm aware of all that. Though in terms of "the system" under consideration, the bird's head is cooled. The heat subtracted from the birds head, when and if "added back to ambient" such "adding back" takes place external to the system, though in actuality, the heat "lost" so to speak, is incorporated into the molecular structure of the water vapor molecule due to a change of state from liquid to vapor and is not "added back" until the water vapor condenses back into a liquid somewhere remote from the system, Possibly as a water droplet in a cloud on the other side of the earth.

    Ummm.... generated, created, virtual synonyms depending on context. You seem to be mincing words to no point. Whatever terminology you use to describe it the result is the same. Water evaporates, the birds head cools, a temperature differential is established.

    "creating energy" if I ever used such a phrase in this context is a euphemism. That is it could be said that an electric generator running on gasoline is "creating energy" though technically it is not literally "Creating" energy out of nothing.

    It has already been stated several times that such an engine would not be able to operate unless an initial temperature differential were established by some other means, that is, by some external source of energy.

    In the case of the engine illustrated by the animation the initial temperature differential might be established by an application of heat and/or cold or by starting the cycle with an auxiliary air compressor.

    Such an auxiliary compressor however would have to be modified somewhat.

    Compressing air generates a great deal of heat but a conventional shop air-compressor is usually equipped with cooling fins and fan to dissipate such heat before the air goes into the tank. In any event the air returns to ambient in the tank. To be of use, the auxiliary compressor would have to be able to compress the air directly into the system without loosing heat. This would not be particularly difficult.

    The animation illustrates an engine in operation after an initial temperature differential has been established by some other means to get the engine started.

    Once the temperature differential has been established by running the engine with an auxiliary compressor or by some other means the engine would then, theoretically, continue to operate as shown, the auxiliary compressor removed.

    Assuming the initial temperature difference has been established:

    The displacer (or piston if you like) in moving towards the hot end of the chamber displaces the air to the cold end. Contact with the cold end causes the air to cool and contract. The cooling reduces the volume of the air so that more air is drawn into the chamber through one of the check valves.

    The displacer then moves in the opposite direction pushing the air to the hot end of the chamber where it is heated and so expands. This expansion increases the volume of the air and some of this hot air is forced out the other check valve.

    We know that in doing work a gas will give up heat, but in this case the gas is in effect doing work upon itself so the heat energy used for compression is retained or added to the air being worked upon.

    So now we have, in effect, ambient air compressing itself with its own heat and extracting more heat in the process and using that heat to draw in more warm air from which more heat can be extracted. (Or more accurately, heat is used to compress the air. The compressed hot air can then be cooled with no further energy input but rather cooling is effected by simply exposing the compressed air to ambient followed by expansion through a turbine (with a load), so it is the resulting cold which causes the contraction of the air in the chamber to draw in more warm air but that cooling is itself carried out due to the initial heating and compression in the same way that a conventional refrigerator/freezer produces cold with an input of energy and initial heating and compression)

    This can only take place up to a point where back pressure would prevent any further compression and heat extraction, but now the pressure is relieved by allowing the compressed air to escape through a narrow orifice in a nozzle allowing it to expand through a turbine which effects rapid cooling.

    If necessary the air could be pre-cooled by exposure to ambient or even pre-cooled by exposure to cold air exiting the turbine if necessary, as is commonly done in the liquefaction of gases.

    In any event I think it should be possible by such means to cool the air to a point below that initially established in order to get the engine started.

    Also any heat thrown off to ambient to effect pre-cooling could be reclaimed for pre-heating the incoming ambient. This might be useful on cold days. Though hot air is more difficult to compress than cold air so there may be some trade-off.

    I hope this helps make things more clear.

    So ambient air is being sucked in and compressed to release the latent heat. The heat is then used as an energy source to run the engine, which engine in reality is also the compressor.

    Once set in operation the engine continually draws in more ambient air and compresses that air using the heat energy extracted from air drawn in and compressed previously.

    As the compressed air is released through the turbine pressure is relieved allowing more air to be compressed and more heat to be extracted.

    There would no doubt need to be some controlling mechanisms to keep things operating at some predetermined levels. Pressure and temperature sensors and controllers etc.

    There is probably some reason this wouldn't work but I wouldn't dismiss it offhand without at least first understanding the intended mode of operation.
    Last edited: Jun 28, 2012
  14. Aqueous Id flat Earth skeptic Valued Senior Member

    "system" is in reference to what? Entropy? If so, that's incorrect. No matter or energy can cross a system boundary. Therefore you can't put a boundary around the the bird itself. Now you have to include the atmosphere.
    Not mincing, but distinguishing an important difference in scientific meaning. Let's use a term we agree on. The water molecule is ejected, and takes its kinetic energy with it. Let's call that transfer. Energy is transferred out of the felt into the atmosphere by evaporation.

    No, there's the case where we use "generation" of electricity, while clearly meaning "conversion" of fuel energy into electricity.

    Until you dispel the idea that the engine furnishes its own power you'll continue to advocate an over-unity design.

    Your diagram makes no sense. There is nothing to cause cooling to occur.

    I presume you know you would need to pull suction on air to cool it down. That's why I was assuming you were powering a piston with the solenoid. Where does your design provide a means of furnishing cold air?

    Until you can explain how to provide cold air, that won't even matter.
    see comment above
    No, because it has no means of causing suction, which is the only way to cool air the down. (Or compressing it, cooling it, and releasing it to expand, like A/C).
    Yeah but there's nothing to cause a cold end, so it won't do squat.
    see previous remark
    Huh? You just told me it has no piston. Therefore it makes no cold air. Therefore nothing will happen, it will just stare back at you.
    Ambient air won't compress itself. And you said you have no power piston. Nothing compresses, nothing heats up or cools down. Everything will remain at ambient, and it will just stare back at you, motionless.
    No, no compression-no nothing. See remarks above.
    No, no compression-no nothing. See remarks above.

    There is only 1 temp in your engine. Room temp. Nothing more.
    Forget starting it. You don't have a power stroke, so you have nothing.
    You're not generating heat, and you're not cooling anything. You just have some motionless parts, all at room temp.
    No, you need to start with a power stroke.
    There is no temperature difference. At best you're moving around some room temp air, for the cost of actuating a solenoid.
    When you find the power stroke, you'll find the compression that went missing. Nothing set in motion keeps running, especially loaded. This won't even move. It has no energy source. It has nothing going for it at all.
    Compression? Looks like cold air (which appears as if by magic), nothing more. What pushes the turbine?
    Again, without a power stroke, none of that matters.
    Without a power stroke you've got nothing. And planning to have it feed itself and rely on external power is not going to solve anything. So far you've introduced a solenoid, a turbine , and an auxiliary device. That's three energy consumers, but not one energy producer. So nothing happens.
  15. Tom Booth Registered Member

    This is really getting tedious. I said previously that I do not believe an Ambient Heat engine of any kind could be a "isolated system" or even a "closed system".

    Above I used the term "system". Obviously from previous statements and from the illustration itself, this is an "open system".


    Isolated System: "an isolated system is a physical system without any external exchange – neither matter nor energy can enter or exit, but can only move around inside. Truly isolated systems cannot exist in nature, other than possibly the universe itself, and they are thus hypothetical concepts only"

    Closed System: "This (an isolated system) can be contrasted with a closed system, which can exchange energy with its surroundings but not matter, and with an..."

    Open System: "... open system, which can exchange both matter and energy."


    As for the rest of your comments, I would suggest you look more deeply into the function of an ordinary Stirling Engine before trying to comprehend my modified version which only uses the basic principle that drives a Stirling. In particular, the definition of a "displacer". How a displacer works, what it does etc.

    The device in my animation has a "displacer" that is controlled with electromagnets (solenoids). It does not have a piston.

    You will also want to study carefully how an "expansion turbine" or "turbo-expander" operates so as to produce both energy to power a load as well as cooling (from compressed air or gas). In particular, the expansion turbine is also used in the "Air-Cycle-System", which is a cryogenic refrigeration system or "flash freezer" system for reaching extremely cold temperatures.

    Kinetic Theory of Gases in connection with how and why an expansion turbine can RECLAIM energy from a compressed gas and produce cold at the same time. Why the gas gets so extremely cold after being compressed and released through a turbine to do work.

    Your incessant questions and miss-statements are becoming rather tiring. No offense but, If you look at a detailed animated diagram of a cooling system or air conditioner and ask "Where's the cooling ?" I'm not sure there is anything more I can do to make things any clearer.

    I understand as AIR is invisible to the human eye and it is difficult for any of us to visualize exactly what it is doing.

    This engine uses air throughout, to carry heat, to compress air, for cooling etc. The energy carrier is air. The "piston" to do the compressing is, in effect an "Air Piston".

    Think of it this way.

    If you expand air to push a piston. On the other side of the piston you have another cylinder where air is compressed by the piston.

    The piston is redundant and serves no purpose and so can be eliminated. Either way the air will compress only to the point where the air in both cylinders is equalized. The piston in the middle serves no real purpose.

    Heat expands the air, the expanding air, in effect becomes a piston to compress the air. the compressed air travels through the equivalent of the expansion tubes and condenser coils etc. on a refrigerator or heat exchanger.

    Remember a refrigerator, freezer, heat exchanger, they are all basically just a compressor or a source of heat and a bunch of different size tubes and coils for the compressed fluid or gas to travel through. There are no moving parts in a gas (Heat Driven) refrigerator. It is difficult to understand how it works. Looks like just a bunch of tubes that do nothing. No piston, no compressor, just a tiny gas flame like a pilot light. How can flame be used to make ice without any moving parts, just a bunch of tubes ? Well, you have to understand basic refrigeration to begin with.

    This engine incorporates an Air-Cycle cooling system, a Stirling Engine, Air pump or compressor, Expansion Turbine, heat exchangers etc. all in one unit with all extraneous or redundant features and moving parts eliminated.

    If you don't have some rudimentary understanding of these things you aren't going to know what you are looking at. Just a bunch of tubes.

    The working fluid or refrigerant (Air) is invisible. The power source (Heat) is also invisible. The Sink (Cold) is invisible.

    I've tried to illustrate what is going on with colored arrows. Red arrows represent hot air, Blue arrows represent cold air. Arrows pointing inward towards one another represent cooling and contraction. Orange or brown arrows represent Ambient, Snowflakes represent extremely cold air.
  16. Aqueous Id flat Earth skeptic Valued Senior Member


    My comment concerning the system boundary was to reinforce the meaning of the law of entropy since you had earlier said you disputed it. There is no creation of energy in evaporation, it's a natural process that can be exploited just like geothermal energy that utilizes the potential difference between ambient temperature differences across a naturally occurring gradient. It's not truly an ambient source, because there is no usable energy when only referenced to ambient. There has to be a second mass at a different temperature, such as the lower (or warmer in winter) ground temp of geothermal energy, or this elusive case with evaporation. This second "ambient" was my point back at my original post.

    As for your engine, you haven't provided an energy source that lowers the temp of the cold side. That's the flaw. And it's not a Stirling engine anyway, you're just calling it that because you have an air moving piston you call a displacer. Without a power stroke, it's not an engine at all. You need energy to lower the temp at the cold side. And over-unity and perpetual motion--as you appear to apply the concepts here--are impossible.

    There is nothing in this engine to keep it cold on the cold side. It will never get cold unless you apply ice or external refrigeration to it. Then when you remove your cooling method, your "cold side" will simply warm back up to ambient. Without a power stroke in the engine, drawing power from a true energy source, there can be no way to maintain a cold side.

    Obviously if there was on iota of reality in this, all the refrigeration systems in the world would have been using them since they were first introduced in the 1800's.

    Despite your frustration, I am driving a point home that reveals the fundamental flaw in your concept. You have no cycle here. You mention refrigeration, but you failed to mention that basic premise: the refrigerant is compressed, making it hot. The hot liquid is cooled in the condenser, bringing it down closer to ambient. It is then released though a venturi into the evaporator, where it decompresses back into a gas, causing its temperature to fall to the operating temp for the cooling system. That is, temperature and pressure are directly proportional.

    Without a power cylinder, you have no way of converting energy. You have no way of compressing or expanding air. Thus you have no way of generating a cold side.

    It was my intent, once you understood this, to walk you through the calculations, so you could understand how to estimate the energy requirements for a given output power and some of the details you continue to misunderstand. After that, you would be better equipped to wrestle with the real problems that designers face.

    The solar powered Stirling engine, using a parabolic reflector, was published sometime in the last decade ago. I also was going to show you that your idea of furnishing electricity to a residence was probably flawed, in the way you posed it. Sunlight under best conditions (noon at the spring/fall equator, clear skies) can yield a maximum of 1kW per sq meter. The parabolic reflector 1 sq meter in surface area will catch a maximum, under those conditions, of 1kW. So regardless of how you design the mirror, you are strictly constrained to the density of power in sunlight. It's not to say a residential solar powered Stirling engine isn't a great idea, only that it needs a very large mirror to run an average household.

    At some point, if you're interested, I can walk you through those calculations. They would invariably take us back to estimating efficiency, and applying Stirling cycle variation for the Carnot cycle, which you also have an aversion to, so you may not be interested. But in this I'm right: the laws of nature can't be repealed because "it seems so". And the Carnot cycle is a compact way of describing those laws and applying them in any device that concerns itself with heat exchange such as this one you propose.
  17. Tom Booth Registered Member

    Not entirely sure as I've discussed entropy, I said I don't think the bird or an ambient heat engine violate entropy but I don't recall having "disputed it".

    Yes, we've already been through that. I think someone else may have said something like that, referring to evaporation as the energy source. That I did dispute.
    Heat powers the cooling system. More or less as in a conventional refrigerator. In this case however, the "compressor" for the refrigerator is a heat engine that uses heat to compress air. Air is the "refrigerant".

    Granted. It's not a Stirling engine. So what? If you want to understand how it is supposed to work (theoretically) the only thing similar to it is a Stirling Engine as it uses the same basic principle. The core element of a conventional Stirling Engine is the displacer. This is what converts a temperature differential into a pressure differential.

    I call it a displacer rather than a piston because it is a displacer not a piston.

    A displacer does not have any "power stroke". The displacer in a Stirling Engine does not have a "power stroke". You are confusing functions.

    In a conventional Stirling the displacer provides an alternating pressure differential to a reciprocating piston. This engine uses check valves to convert the "AC" to "DC" like diodes (or rectifier) in an electrical circuit to provide a steady pressure to power a turbine.

    Where is the "power stroke" in a conventional Gas (Heat Driven) refrigerator ?

    Well golly, it heats a gas and the gas pressurizes itself !!!!

    No, that's impossible, where's the power stroke? I guess we have to scrap gas refrigerators too.

    As I said, you need to look as the "Air Cycle System". In an air cycle system there is the same basic process of compression and expansion but no change of state is necessary. The expansion turbine serves the same function as the venturi but is more effective at lowering temperature. Instead of simply being released through a venturi to decompress and cool the compressed air is released through a turbine where it expands and does work to turn the turbine and power the load on the turbine. This takes more energy and results in greater cooling than expansion alone.

    Again, many refrigeration systems have no "power cylinder". A conventional gas refrigerator (using ammonia as a refrigerant) has no power cylinder. Heat applied from a small gas flame causes the gas to expand and pressurize itself. The principle driving this engine is very similar.

    I appreciate your desire to set me straight and help in other ways, but I don't think that is possible if you do not understand at least how this engine is supposed to work in principle. Otherwise any calculations would be based on some misunderstanding.
  18. Tom Booth Registered Member

    Here are a few illustrations of the "pump" or compressor that might be a little easier to understand without all the attached components.

    It is the same basic system that drives the piston in a conventional Stirling engine using only a temperature differential but without the piston.

    It's function is the same, to heat and cool and thus expand and contract a volume of air, but in this case the air flow is directed in one direction due to the presence of the one-way check valves.

    Like a Stirling engine it can run operate on a source of heat or it can use a cold sink.

    Please Register or Log in to view the hidden image!

    Please Register or Log in to view the hidden image!

    I have already posted a video of the actual model I made of this pump to see if the concept would work. Considering the crudeness of the model, made of tin cans and other junk I had around the house, I consider the results rather positive as even with faulty check valves it did manage to pump some air into a balloon.

    If a compressor can operate directly on a temperature differential then it would seem that the rest of the idea is feasible or at least worth further experimenting.
  19. Aqueous Id flat Earth skeptic Valued Senior Member

    The point is that you need compression. A power stroke. A power cylinder. There is no way to change the thermodynamic state of air without compression(or suction).

    First of all it's not an engine. Second, it's a chemical refrigerator that relies on the room-temp. evaporation of ammonia and its absorption by water. We can cover that later if you want. Here, we're talking about producing cold air. Entirely different animal.

    No, the ammonia-asorption process uses heat to evaporate the ammonia out of solution, not for compression purposes. And where does your air ever get heated above ambient? (Even though it's irrelevant to the ammonia refrigerator.)

    Are you evaporating ammonia into water? No. Irrelevant. We are talking about chilling air, and we're talking about developing torque - an engine.

    Change of state is the basis for refrigeration, not necessarily for engines. Internal combustion engines need so much air they are effectively in the gas phase all the time. The Stirling engine happens to work, with limitations, on air. If you were able to get it to go through phase change, you would jump in efficiency since there is huge volume advantage between them (22:1). Of course this has nothing to do with your device. Obviously you're not going to change state. You don't even have a power piston. The question was: what causes any air in your device to change temp at all since you have no compression. The answer is: nothing. For this reason you will have no cold side.

    You have nothing to power the turbine with. You have no power stroke, therefore no power. There is no pressure to drive the turbine. There is no expansion of air, no temperature differential, nothing.

    No, unlike the compression refrigerator, you have neither compression nor state change. You have no power to drive anything.The turbine will remain motionless because there is no pressure differential to drive it, since you have no compression.

    You have no pressure, no compression, there is nothing to push the turbine, so it will just sit idle.

    All engines do.

    It's not pressurizing it - it's evaporating the ammonia out of solution. And it's completely unrelated to your device. The ammonia refrigerator exploits (1) the chemical affinity of water to absorb ammonia, producing a liquid (aqueous) phase change (2) the property that heating the aqueous ammonia drives off the anhydrous ammonia, returning it to the vapor state; and (3) fuel, to provide the energy needed to heat the liquid ammonia.

    You have none of these going for you. You have ambient air, with nothing to change its temperature, pressure or volume. So it will remain static.

    If I can't understand something as simple as this, it must be defective. And it is. There can be no cooling of ambient air without expansion--compression through an expansion valve or suction. And there is no compression or expansion without the addition of energy--in this case a power stroke fueled by a substantial potential difference between source and sink. But there is none. You have ambient as source, and nothing for sink temp except your external ice of cooling device which do nothing to ambient air that's an different than what you get when you set an iced drink on the table--condensation. The cool wet area will gradually warm back to ambient temp without any effect whatsoever. Your displacer will accelerate that process.

    Again, you can't have an engine without a potential energy difference between the source and the sink. And it has to be a continuous (Energy is power x time, meaning continuous) supply of power.

    It seems you've come to the opinion that air compresses air. But that makes no sense. The only way we see that in nature is the way the atmosphere bears down on itself. Obviously that had nothing to do with your device.

    I can think of no practical way to work with air without compression. It's 78% N[sub]2[/sub] which is highly inert (owing to the triple bond). All you have is this mostly inert gas at ambient. You would have to have a compressor to change its temp. Think of a bicycle pump, and the way it barely gets warm if you work it fast and hard. And you'll get tired doing it.

    You wouldn't even doubt what I'm telling you if you were accustomed to referring to the Carnot cycle to establish the best case operating conditions for the engine. Of course, without a potential difference in energy source and sink, and without compression, you have no engine. Without an energy source and phase change you have no refrigerator.

    So far all you've been able to rely on is that ambient air, due to some magical effect of "priming" it with a charge of cold air, will begin cycling, as if a power stroke were present. But it's not. So it won't.
  20. Aqueous Id flat Earth skeptic Valued Senior Member

    After spending several days repeating that you're only using a displacer, now you're talking about compression. When I assumed the solenoid plunger was the power piston,you insisted it was serving only the displacer function, but now you've got it doing compression. :bugeye:
  21. Tom Booth Registered Member

    I believe that your description is incomplete.

    The heat applied boils the ammonia/water mixture. This doesn't just "evaporate" the ammonia gas into the open air but into a confined space, into a pipe. This creates pressure just like a pressure cooker. Heat is then removed from the pressurized gas and it condenses to a liquid as heat is removed. The "steam" ammonia under pressure is cooled down and condenses into a liquid.

    In effect, the ammonia in the condenser is "compressed" or put under pressure by the boiling ammonia/water in the boiler. Without this build up of pressure the ammonia would never condense into a liquid when cooled.

    But the ammonia refrigeration system is more complex than a simple air-cycle system.

    Do you dispute the fact that heat applied to a gas in a confined space creates pressure ?

    That if you continue to introduce additional gas into the same confined space and heat it the gas already inside would be compressed or put under additional pressure ?
  22. Tom Booth Registered Member

    It seems obvious that you do not understand the function of a displacer in a Stirling Heat Engine. I will attempt a walk through the process.

    We know, I think, that if you take a sealed canister of air of fixed volume and heat it, by whatever means, pressure inside the canister will increase.

    On the other hand, if you take the same sealed canister and cool it pressure will decrease.

    The effect, when the air is heated is the same as if you took a larger canister of air and decreased the volume. The air in the canister would pressurize and heat up.

    Likewise, when you cool the canister along with the air inside, the result is the same as if you started with a smaller canister and increased the volume. You then have cooler air at reduced pressure.

    To say that the air is "compressed" by the action of the displacer is probably a misuse of terminology. It would be more appropriate I suppose to say that the air is pressurized when heated and depressurized when cooled.

    When air in the canister is heated the air in the canister wants to expand but can't as the volume is fixed. Instead the pressure increases.

    When the air in the canister is cooled the air wants to contract but can't. Instead the pressure drops or a partial vacuum is created.

    Now imagine the same canister but instead of either heating or cooling it you simultaneously heat one end and cool the other.

    Inside the canister you place a block of material that fills up 1/2 of the space in the canister.

    If the block is moved to the hot end it displaces the air in the hot end to the cold end. At the cold end the air is cooled and contracts or "depressurizes" and a partial vacuum is created.

    If the block is moved to the cold end it displaces the air to the hot end where the air is heated and pressurized.

    If the displacer moves from one end to the other very rapidly the air is heated and cooled very rapidly causing a rapid change in pressure.

    If the canister were in fact completely sealed this would all be to no effect.

    In a Stirling Engine the canister or "displacer chamber" is equipped with a smaller cylinder attached to it.

    As the displacer moves back and forth the changes in pressure cause the piston in the attached cylinder to move in and out.

    It is well known that more power is developed to move the piston than is required to move the displacer as the power is being derived not from the action of the displacer but from the heat applied.

    Heat is converted to pressure to drive the piston out. The energy derived comes from the heat applied not from the displacer.

    Since the only thing the displacer is doing is shunting air up and down there is very little resistance to its movement. As a result of its movement however, the air in the canister is heated and expands rather explosively driving the piston.

    More power is developed to drive the piston than is required to keep the displacer moving, so the piston can drive a crankshaft and the displacer can be attached to the same crankshaft. Since it takes but a relatively small amount of energy to move the displacer, the excess energy can be used to drive whatever load is put on the engine, such as an electric generator.

    So heat causes the air in the canister to pressurize. The pressure drives the piston. The heat is converted into mechanical energy to drive the load on the engine.

    Whatever heat is not converted is dissipated to the cold end of the chamber when the displacer moves to the hot end.

    So the displacer, of itself does nothing but move a volume of air back and forth in a chamber. Without a temperature differential, that is, without one end of the canister being relatively hot compared to the other end, the movement of the displacer would have no effect. There would be no temperature change in the air as it was shunted back and forth and so no pressure change to drive the piston.

    So the displacer does not, of itself, do more than bring the air in the canister into contact with heat and then remove it from the heat. As the air comes in contact with the hot end of the chamber it is heated and pressurized and the pressure drives the piston out. The air is then removed from the heat allowing the piston to return then the air is put back in contact with the heat and expands again.

    The displacer is not powering the engine, or pushing the piston. heat is expanding the air, causing the air to pressurize and the pressurized air is pushing the piston. Heat, not the displacer is powering the engine.

    So it would not be correct to think of the displacer as a piston with a "power stroke". The engine is fueled by heat. The displacer only serves to intermittently bring the air in the chamber into contact with that heat and remove it again.

    If instead of powering a piston, the heated and expanded air could be captured and retained for later use it could instead power a turbine.

    So you replace the piston and its cylinder with a one way valve. When the displacer moves the air in the displacer chamber to the hot end the air is pressurized and the valve opens and allows the pressurized air to escape through the valve, then the valve closes.

    Theoretically, the pressurized air that escapes could be used to turn a turbine rather than pushing out a piston. No ?

    Just as the piston being driven by the pressurized air develops more power than is required to keep the displacer moving so the turbine should develop more power than is required to keep the displacer moving as the power is coming from the heat not from the mechanical input to the displacer.
  23. Tom Booth Registered Member

    The animated diagram previously posted shows a simple LTD type Stirling displacer arrangement. I think that it would also be possible to demonstrate or test Tesla's idea with a "Lamina Flow" type Stirling as well.

    I find it curious that in the YouTube video previously posted of the Lamina Flow Stirling driving a linear alternator that the designer found it necessary to install a bumper or spring to prevent the piston from banging into the end of the cylinder on its RETURN STROKE, that is, against the pressure of the heated expanding air!

    How might this be possible ?

    The air, heated, expands and pushes the piston. The magnet attached to the same rod passes the coils in the alternator and generates electricity. The piston reaches the end of its stroke, the heat has been largely exhausted, having been converted to electricity, the air in the cylinder cools and implodes, the piston returns, once again passing the magnet past the coils generating additional electricity, presumably effecting more cooling. The additional cooling effected on the return stroke causes the air to contract further and the result is that the piston is drawn further in than than the point at which it started.

    This would suggest that in passing by the coils the second time on the return trip the air is being cooled to a temperature below its starting temperature.

    The effect might be increased if the shaft were extended beyond the alternator and attached to a flywheel in such a way as to use the momentum stored in the flywheel to extend the throw somewhat beyond its natural stopping point.

    As the flywheel pulled the piston outward beyond the point where it would be inclined to reverse its direction and move inward the air in the cylinder would be mechanically expanded and so grow colder. Even colder than whatever degree of cold is causing it to bang into the end of the cylinder on its return stroke.

    In effect, at the extent of its outward movement, being drawn by the flywheel slightly further some refrigerating effect might be the result.

    If such an engine were running on ambient heat as a heat source, perhaps this additional cooling could serve as a sink.

    In such a case, rather than adding a heat sink to the cold end to dissipate heat to ambient, the cold end of the cylinder would need to be insulated against heat infiltration FROM AMBIENT.

    Of course, this would be considered ludicrous and goes against everything we know about thermodynamics and Carnot and yada yada yada, but if Tesla was right then such an arrangement should be possible as less energy would be needed to maintain the sink or "cold hole" at the cold end of the cylinder than is added at the hot end as the energy added at the hot end would largely be converted into electricity and so would not have to be dissipated as heat.

    Who, however, would ever conceive of INSULATING the heat sink ?

    Chances are nobody has ever tried it.
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