Stirling Engine & Heat Pump

[Tom Booth]

The authors of this page (and many others I've looked at) appear to agree:

By utilizing both hot water and cooling simultaneously, the system’s COP will double if we make use of the cooling function.

https://naturalrefrigerants.com/product ... heat-pump/

[Fool]

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That is a little like saying, since an electric motor runs better when the voltage is higher, and a battery charger takes Joules out of the negative side and puts them in the positive side, we should double the efficiency of a generator because we are using it to run a motor.

A heat engine runs from heat coming from the hot side, so it is only the COP of the heat pump that counts. TC and Th stay the same. W/Qh=n

A heat pump and refrigerator are the same thing. The difference in COP between the two is only a viewpoint. The same amount of heat is pulled from the cold plate Qc. The same amount of heat is moved into the hot plate Qh. The same amount of work is input W. The difference is Qh=Qc+W.

The ideal maxim COP of a heat pump is always the COP of the refrigerator+1. It is higher because the Joules of work are added the hot plate.

If a heat pump is used to both increase the hot plate temperature and decrease the cold plate temperature. The COP will reduce as the temperature difference increases.

If you are unable to find a Stirling engine boasting of efficiencies and temperature values that are correct for your COP heat pump values. Putting any random two together is probably pointless and a waste of time and effort.

I would buy or build a few low cost Stirling's and test them properly before buying a compatible heat pump. Remember you are looking for an engine that gets 30% overall efficiency or higher on 50F and 75F temperature values.

Remember, what is being asked here is dependent on overall efficiency. You aren't going to get any free energies unless overall efficiencies and COP's are better than the Carnot Limits, at the same temperatures. Don't be swayed by improperly measured efficiency claims. Look for properly measured overall efficiency. W/Qs , Qs is heat supplied. W is work output measured.

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[Tom Booth]

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That is a little like saying, since an electric motor runs better when the voltage is higher, and a battery charger takes Joules out of the negative side and puts them in the positive side, we should double the efficiency of a generator because we are using it to run a motor.

I can make no sense out of whatever it is your trying to say there.

A heat engine runs from heat coming from the hot side, so it is only the COP of the heat pump that counts. TC and Th stay the same. W/Qh=n

All sources I've found that comment on the subject disagree.

They state that COP is a measure of "useful" output relative to input. For most applications, heating OR cooling only the heat OR cold is "useful".

For a Stirling engine Qh, the amount of heat the engine can take in in a cycle is determined by the ∆T. So Qh can be increased by either raising Th, or lowering Tc OR BOTH. So both the heating COP and cooling COP are "useful" and can be added together.

A heat pump does both heating and cooling by moving heat. Lowering the temperature in one location, at the evaporator, and raising the temperature at another location, the condenser.

Like digging a hole and moving dirt. A ball placed at the top of the pile of dirt will have more potential energy if it can roll down into the hole the dirt was moved out of.

Resize_20241006_134432_2903.jpg (158.23 KiB) Viewed 756 times

A heat pump and refrigerator are the same thing. The difference in COP between the two is only a viewpoint. The same amount of heat is pulled from the cold plate Qc. The same amount of heat is moved into the hot plate Qh. The same amount of work is input W. The difference is Qh=Qc+W.

The problem with your reasoning is you use Qh and Qc as if they were Th and Tc. Not the same thing.

The heat/energy in the ambient surroundings available for the heat pump to move is not finite but unlimited. Also, unlike my analogy of balls rolling into a dug hole from a mound of dirt 2x further than the height of the mound OR the depth of the hole, a Stirling engine CONVERTS the heat or potential made available at the top of the mound. It does not move the heat/energy back down onto the "cold hole" it converts it.

The ideal maxim COP of a heat pump is always the COP of the refrigerator+1. It is higher because the Joules of work are added the hot plate.

So, that just means the work of the heat pumps compressor, or heat generated, by the compressor reappears at the condenser to be utilized by the Stirling engine.

So the Stirling engine can utilize both the heat generated by the heat pump, as well as the heat MOVED and also the "cold hole" created that further increases the ∆T available to the Stirling engine.

If a heat pump is used to both increase the hot plate temperature and decrease the cold plate temperature. The COP will reduce as the temperature difference increases.

True. Therefore the logic in using a low temperature differential type Stirling engine minimizing the ∆T for the heat pump and maintaining a high COP.

Your contention that an LTD type Stirling is inherently less efficient than a HTD Stirling is what I do not agree with. An LTD has more surface area for effective heat intake relative to gas volume, so can utilize a low ∆T much more effectively than a HTD Stirling with a relatively small surface area to working fluid volume ratio.

If you are unable to find a Stirling engine boasting of efficiencies and temperature values that are correct for your COP heat pump values. Putting any random two together is probably pointless and a waste of time and effort.

Agreed. I think. An appropriate heat pump with an appropriate working fluid should be matched with an appropriate Stirling engine for a given climate.etc. This requires careful and intelligent engineering. Nothing "random" about it. Also the two machines would need to be well integrated as one working unit. Something like this:

Compress_20240826_204943_3280.jpg (101.39 KiB) Viewed 756 times

There the throttling valve has been replaced by an expansion turbine coupled to the compressor in a bootstrap "air-cycle" type heat pump configuration. Also the hot and cold heat exchangers for the LTD Stirling engine ARE the condenser and evaporator of the heat pump. The system is fully integrated into a very simple single unit.

I would buy or build a few low cost Stirling's and test them properly before buying a compatible heat pump. Remember you are looking for an engine that gets 30% overall efficiency or higher on 50F and 75F temperature values.

Remember, what is being asked here is dependent on overall efficiency. You aren't going to get any free energies unless overall efficiencies and COP's are better than the Carnot Limits, at the same temperatures. Don't be swayed by improperly measured efficiency claims. Look for properly measured overall efficiency. W/Qs , Qs is heat supplied. W is work output measured.

You can stick your "Carnot Limit" where the moon don't shine. Obsolete pseudoscience easily and already experimentally disproven many times in many ways.

[Fool]

The problem with your reasoning is you use Qh and Qc as if they were Th and Tc. Not the same thing.

Qh and Qc do not charge Th and Tc, unless their mass is small. Then, the governing equation is Q=MCvT.

It leaves no hole, nor hill to climb. Shoveling dirt is a bad analogy.

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[Fool]

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Your contention that an LTD type Stirling is inherently less efficient than a HTD Stirling is what I do not agree with.

You are the one that complains about engines being designed with the hot and cold zones inches apart. By the very inspection of a LTD Stirling Engine, I'd say they are separated by about an inch, maybe less. Go figure? Why would you think they could have any chance of being anything more than way less efficient.

Also, classical thermodynamics, including PhD Senft agree with me.

You can stick your "Carnot Limit" where the moon don't shine.

Again, this is what we teach little pre-K and elementary students is unacceptable, inappropriate, language. Grow up. Didn't your mommy teach you any better.

P. S., Carnot is not wrong, you are lacking authority for this.

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[Tom Booth]

The problem with your reasoning is you use Qh and Qc as if they were Th and Tc. Not the same thing.

Qh and Qc do not charge Th and Tc, unless their mass is small. Then, the governing equation is Q=MCvT.

It leaves no hole, nor hill to climb. Shoveling dirt is a bad analogy.

Shoveling dirt is an analogy for MOVING heat via a heat pump to create a temperature difference. The heat pump, starting at ambient or equilibrium takes heat away from one area at the evaporator, effectively "digging a hole" and lowering the temperature, then piles the "dirt"/heat up in another area at the condenser, making a "hill" raising the temperature.

The heat pump creates a ∆T by both lowering the temperature below ambient for refrigeration and raising the temperature above ambient for heating.

Generally, in summer OR winter, only one or the other, heating OR cooling is useful, but in reality a heat pump ALWAYS DOES BOTH.

COP is based on either the height of the ∆T above ambient or the height of the "dirt hill" or the depth of the ∆T below ambient. Whichever is "useful".

For a Stirling engine the entire ∆T is useful, from the highest temperature at the condenser to the lowest at the evaporator.

So the COP representing the "useful" portion of the ∆T created by the heat pump is the cooling COP plus the heating COP because to a Stirling engine BOTH are "useful".

"Qh and Qc do not charge Th and Tc"

A heat pump creates Th and Tc from the ambient equilibrium.

The delta-T determines Qh. Efficiency determines Qc.

Without a ∆T there is no Qh, no possibility of "heat" input.

Increasing the ∆T potentially increases Qh, how much heat the engine can take in each cycle.

Your statement "Qh and Qc do not charge Th and Tc" doesn't make any sense and I never said that Qh and Qc change Th and Tc.

[Tom Booth]

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Your contention that an LTD type Stirling is inherently less efficient than a HTD Stirling is what I do not agree with.

You are the one that complains about engines being designed with the hot and cold zones inches apart. By the very inspection of a LTD Stirling Engine, I'd say they are separated by about an inch, maybe less. Go figure? Why would you think they could have any chance of being anything more than way less efficient.

I don't "think" anything, a-priori. I base my conclusion on numerous experiments and their results.

Further, a Senft LTD is not an LTD type Stirling. Senft's LTD did not include a regenerator, so is arguably, not a Stirling engine. The most astonishing experimental results were seen using modified LTD engines with the addition of a regenerator. A very simple addition that makes the Senft LTD real Stirling. That is an "LTD type Stirling"

Also, classical thermodynamics, including PhD Senft agree with me.

I doubt Senft actually agreed with much of the incoherent drivel, nonsense and corrupted, bastardized idiocy that generally flows from your ignorant head onto these pages.

Maybe you can provide a reference where Senft's says: I agree with FOOL on the Stirling engine forum.

Needless to say ,LTD designs, even without a regenerator are remarkably efficient, as are Stirling engines in general.

In my reading, Senft argues that the Stirling engine is potentially MORE efficient than the supposedly "perfect" Carnot engine.

For example he offers this PV diagram:

IMG_20241008_115528068.jpg (262.03 KiB) Viewed 722 times

And goes as far as to state in the text (pgs. 31 & 32 of Mechanical Efficiency of Heat Engines) about Carnot: "...it's mechanical efficiency is inherently low."

You can stick your "Carnot Limit" where the moon don't shine.

Again, this is what we teach little pre-K and elementary students is unacceptable, inappropriate, language. Grow up. Didn't your mommy teach you any better.

P. S., Carnot is not wrong, you are lacking authority for this.

The Carnot efficiency limit is baseless nonsense without foundation since it was based on the obsolete, depreciated, experimentally disproven Caloric theory.

And in your own words recently, appeal to authority is a fallacy.

You are a habitual liar who does not care what BS or nonsensical crap he posts. You don't care anything about truth. All you do here is try your best to derail and disrupt others conversations and research. Your a useless Troll spreading misinformation, lies and idiocy at every turn.

[Tom Booth]

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That is a little like saying, since an electric motor runs better when the voltage is higher, and a battery charger takes Joules out of the negative side and puts them in the positive side, we should double the efficiency of a generator because we are using it to run a motor.
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With some additional consideration, I can see the point you are trying to make here.

Your analogy, however, depends upon the obsolete Carnot principle that heat is a fluid substance that flows from a hot source to a cold sink, like water, flows from high to low.

Apparently this is true of electricity. Electricity is composed, at least in part, of a "material" substance. Electrons have mass. Electricity is the flow of electrons through a wire.

Apparently, however, heat is a more "pure" form of energy, or transfer of energy, not attached to or permanently associated with an electron or any other mass or material substance.

Experimentally, it can be (and has been, Joule etc.) demonstrated that heat, converted to work, does not "flow through" a heat engine from source to sink in the same way that electrons flow through a wire from positive to negative (actually vice-versa ?).

Heat that is converted to work output by a heat engine never exits the engine as heat.

An engine with a ∆T running between a high temperature heat pump condenser and ambient would only be utilizing 1/2 the potentially "useful" ∆T supplied by the heat pump. But that is how COP is calculated, based on just 1/2 of the ∆T created by the heat pump. Either between the hot condenser and ambient OR the cold evaporator and ambient.

Comparing a heat engine that consumes or converted the heat it takes in with an electric motor through which electricity merely passes is apples to oranges.

[Fool]

You are a habitual liar who does not care what BS or nonsensical crap he posts.

I am lying.

Even a habitual liar say truth once in a while. Perhaps you should listen to those times. Especially when math and logic are being presented.

The Carnot efficiency limit is baseless nonsense without foundation since it was based on the obsolete, depreciated, experimentally disproven Caloric theory.

So what! It is challenged by every first year ignoramus college student based on his religious beliefs that nature should be as he and his paster demands until they learn and teach themselves the logic of how it can be derived. Some never learn. It has stood up against every scientific and mathematic challenge of modern thermodynamic and physics theory. If you'd learned correctly, it is what ended the caloric theory. There is nothing in modern theory that contradicts it, but it does contradict Caloric Theory.

You're bashing something that you are ill-equipped to understand. It is humorous at best, but basically just mean and nasty.

And in your own words recently, appeal to authority is a fallacy.

Authority isn't being appealed to. All that is needed is a robust understanding of modern science. Inability to understand modern science is the inability to be an authority. You appear to lack that understanding.

If you only could supply the answer to; the integral of, 2X dx, and what it means, it will be a bare minimum begining of what you need to learn to understand Carnot.

P.S., I have no doubt that the "mechanical efficiency" of a Stirling could potentially be better than Carnot. To get the same work out per cycle a Carnot must be larger. But that is a mechanical problem not a thermodynamic efficiency.

All Senft's engines have regenerators. Read the book "An Introduction to Low Temperature Differential Stirling Engines" by James Senft.

He uses coffee filter material for the regenerator in his LTD Stirling engines. Especially the P-19.

He says, build one with and without a regenerator, see which one has more kick.



Please explain to me how you are going to pump heat from the cold sink to the hot sink at 10 Joules per run or cycle or Watts, and change the temperature of the cold sink when it is the hull of a battleship in the North Atlantic and the hot source is the sun because it's solar powered?

Heat pumps in the winter are for keeping your house at a constant temperature inside, while pulling heat from the infinite capacity outdoors cold atmosphere. To make up for heat transfer through the insulation.

In the summer they keep your house at a constant temperature by pumping heat out of the house and pushing into the outdoors infinite hot atmosphere. To make up for heat transfer through the insulation.

Transferring heat can at times have little effect on source or sink temperature if their masses are very large compared to the engine.

For a smaller mass, such as a refrigerator, running the heat pump only cools the inside by a few degrees and heats the room by only a few degrees. Yes, on startup it changes by more, big deal, just a transitional period.

If you insist on digging. It is like digging a small hole in the floor of a valley near sea level, and depositing it on top of mount Washington. It is a very small change in relevant elevation difference. 6288 feet pretty much with or without the addition of a 6 inch hole or mound. Especially if you walk up the hill for each dirt scoop. Heat pumps must move little amounts of heat up the full temperature difference hill.

At startup, for a refrigerator the Carnot COP is infinite. For a Stirling engine, that startup COP would be met with an efficiency of zero. Zero times infinity in this case will have a value of 1 or less, 100% or less.

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[Tom Booth]

You are a habitual liar who does not care what BS or nonsensical crap he posts.

I am lying.

Even a habitual liar say truth once in a while. Perhaps you should listen to those times. Especially when math and logic are being presented.

The Carnot efficiency limit is baseless nonsense without foundation since it was based on the obsolete, depreciated, experimentally disproven Caloric theory.

So what! It is challenged by every first year ignoramus college student based on his religious beliefs that nature should be as he and his paster demands until they learn and teach themselves the logic of how it can be derived. Some never learn. It has stood up against every scientific and mathematic challenge of modern thermodynamic and physics theory. If you'd learned correctly, it is what ended the caloric theory. There is nothing in modern theory that contradicts it, but it does contradict Caloric Theory.

You're bashing something that you are ill-equipped to understand. It is humorous at best, but basically just mean and nasty.

And in your own words recently, appeal to authority is a fallacy.

Authority isn't being appealed to. All that is needed is a robust understanding of modern science. Inability to understand modern science is the inability to be an authority. You appear to lack that understanding.

If you only could supply the answer to; the integral of, 2X dx, and what it means, it will be a bare minimum begining of what you need to learn to understand Carnot.

P.S., I have no doubt that the "mechanical efficiency" of a Stirling could potentially be better than Carnot. To get the same work out per cycle a Carnot must be larger. But that is a mechanical problem not a thermodynamic efficiency.

All Senft's engines have regenerators. Read the book "An Introduction to Low Temperature Differential Stirling Engines" by James Senft.

He uses coffee filter material for the regenerator in his LTD Stirling engines. Especially the P-19.

He says, build one with and without a regenerator, see which one has more kick.



Please explain to me how you are going to pump heat from the cold sink to the hot sink at 10 Joules per run or cycle or Watts, and change the temperature of the cold sink when it is the hull of a battleship in the North Atlantic and the hot source is the sun because it's solar powered?

Heat pumps in the winter are for keeping your house at a constant temperature inside, while pulling heat from the infinite capacity outdoors cold atmosphere. To make up for heat transfer through the insulation.

In the summer they keep your house at a constant temperature by pumping heat out of the house and pushing into the outdoors infinite hot atmosphere. To make up for heat transfer through the insulation.

Transferring heat can at times have little effect on source or sink temperature if their masses are very large compared to the engine.

For a smaller mass, such as a refrigerator, running the heat pump only cools the inside by a few degrees and heats the room by only a few degrees. Yes, on startup it changes by more, big deal, just a transitional period.

If you insist on digging. It is like digging a small hole in the floor of a valley near sea level, and depositing it on top of mount Washington. It is a very small change in relevant elevation difference. 6288 feet pretty much with or without the addition of a 6 inch hole or mound. Especially if you walk up the hill for each dirt scoop. Heat pumps must move little amounts of heat up the full temperature difference hill.

At startup, for a refrigerator the Carnot COP is infinite. For a Stirling engine, that startup COP would be met with an efficiency of zero. Zero times infinity in this case will have a value of 1 or less, 100% or less.

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All your arguments are transparent nonsense for anyone with any common sense or actual knowledge about how heat pumps operate, so I'm not going to bother.

I'll just point out one thing.

A heat pump does not start out, as you say:

like digging a small hole in the floor of a valley near sea level, and depositing it on top of mount Washington. It is a very small change in relevant elevation difference. 6288 feet pretty much with or without the addition of a 6 inch hole or mound. Especially if you walk up the hill for each dirt scoop. Heat pumps must move little amounts of heat up the full temperature difference hill.

If the Stirling is Low ∆T then the heat pump will never have any necessity to pump the heat 6288 feet to the top of mount Washington.

The heat pump is basically just MOVING heat on a level plane. Infact, coupled with evaporative cooling or any slight environmental temperature difference such as sun or shade, daytime and nighttime, the heat pump could be MOVING heat down hill at a ridiculously high COP.

Of course, I could always be wrong.

Someone needs to actually build such a combined heat pump / Stirling and successfully endure the inevitable attacks, ridicule, stonewalling, sabotage, kidnapping, murder and such from people like you.

[Fool]

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All your arguments are transparent nonsense for anyone with any common sense or actual knowledge about how heat pumps operate, so I'm not going to bother.

As George Carlin said, think about how smart, or poorly educated, the average man/woman is. Then realize half the population 4.1 billion, is stupider than that. Or as my friend said, I don't think too highly of common sense. What we need is superior sense.

It is too bad you have less than common knowledge and less than common sense.

The heat pump is basically just MOVING heat on a level plane.

Starting at 20 C.

One degree plus and minus.
Max COP= 294/(294-292) = 147 or 14,700%
Max efficiency n=(294-292)/294 = 0.0068 or about 0.68%
Math check .0068 x 147 = 0.9996 or about 1 or 100%

2 degrees +/-
Max COP= 295/(295-291) = 73.75 or 7,375%
Max efficiency n=(295-291)/295 = 0.013559 or about 1.4%
Math check .013559 x 73.75 = 0.9999 or about 1 or 100%

10 degrees +/-
Max COP= 303/(303-283) = 15.15 or 1,515%
Max efficiency n=(303-283)/303 = 0.066 or about 6.6%
Math check .066 x 15.15 = 0.9999 or about 1 or 100%

Please make note that as the temperature difference increases, the COP decreases and the efficiency increases. Also note that the expected return from the combined machine remains at 100%. This means that if your engine and heat pump combination is perfect you will get back all that you put in for zero net gain. It is conservation of energy, first law. Most likely both machines will have half the max or less, so you will get back 25% of what you put in for a gain of zero, do nothing machine. A loss of 75%

So much for your level plane.

Infact, coupled with evaporative cooling or any slight environmental temperature difference such as sun or shade, daytime and nighttime, the heat pump could be MOVING heat down hill at a ridiculously high COP.

Evaporative cooling is an energy source, similar to burning fuel.

Shade is cooling by atmospheric sink. It is another energy level.

Powering a device with extra power does increase output, but not the 100% return.

Someone needs to actually build such a combined heat pump / Stirling and successfully endure the inevitable attacks, ridicule, stonewalling, sabotage, kidnapping, murder and such from people like you.

That is a horrible lie. People like me do not kill people like you. That is why I have friends. I don't kill my friends. My work here is educational in an attempt to help my friends make more friends, and not become ignorant outcasts. Please stop that baseless libel.

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[Tom Booth]

The heat pump is basically just MOVING heat on a level plane.

Starting at 20 C.

One degree plus and minus.
Max COP= 294/(294-292) = 147 or 14,700%
Max efficiency n=(294-292)/294 = 0.0068 or about 0.68%
Math check .0068 x 147 = 0.9996 or about 1 or 100%

2 degrees +/-
Max COP= 295/(295-291) = 73.75 or 7,375%
Max efficiency n=(295-291)/295 = 0.013559 or about 1.4%
Math check .013559 x 73.75 = 0.9999 or about 1 or 100%

10 degrees +/-
Max COP= 303/(303-283) = 15.15 or 1,515%
Max efficiency n=(303-283)/303 = 0.066 or about 6.6%
Math check .066 x 15.15 = 0.9999 or about 1 or 100%

Please make note that as the temperature difference increases, the COP decreases and the efficiency increases. Also note that the expected return from the combined machine remains at 100%. This means that if your engine and heat pump combination is perfect you will get back all that you put in for zero net gain. It is conservation of energy, first law. Most likely both machines will have half the max or less, so you will get back 25% of what you put in for a gain of zero, do nothing machine. A loss of 75%

So much for your level plane.

Your computations are crap.

Meaningless nonsense based on obsolete theory.

As I said, you're like the Captain of a sinking ship of obsolete science.

[Fool]

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Your computations are worse.

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All you know is nothing. All I know is that I know nothing. I'm a step up on you. I at least know we are all bozos on this bus.

https://m.youtube.com/watch?v=lmWFrMq3qNY

https://m.youtube.com/watch?v=YKZtt2yEwfs

Gary Larsen

ship-of-fools-car-of-idiots-v0-qr5uhpr370zc1.jpeg (245.78 KiB) Viewed 675 times

https://m.youtube.com/watch?v=eBXmNgUzDyc

I hope you are enjoying the night.

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[Tom Booth]

finger-in-the-dike.jpg (258.04 KiB) Viewed 668 times

[Fool]

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When you start succeeding in constructing perpetual motion machines, or engines that are more efficient than Carnot, people will stop laughing at you. You're the one lacking any mathematics, data, or extraordinary evidence. You are just full of wind, spite, and vituperation.


When a person is clinging to the refuted mystic belief that perpetual motion is possible, they soon start grasping at straws, lying, defrauding, and cursing.


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