Physicists help needed!!! Current technology limitations.

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Light, one of your nicknames is "that a$$hole", isn't it? You have all that teaching experience and you don't know how to take the high road or how to quit when ahead. Maybe you need more teaching experience. There are some community colleges in western Kansas where you might be able to round yourself out.

You went over the line when you accused me of trying to look like I knew more than I did when I honestly expressed an opinion. Frankly, I don't care so much what you think of me, but I don't think you're particularly honest and I do think you're way too overbearing.
 
MetaKron said:
Light, one of your nicknames is "that a$$hole", isn't it? You have all that teaching experience and you don't know how to take the high road or how to quit when ahead. Maybe you need more teaching experience. There are some community colleges in western Kansas where you might be able to round yourself out.

You went over the line when you accused me of trying to look like I knew more than I did when I honestly expressed an opinion. Frankly, I don't care so much what you think of me, but I don't think you're particularly honest and I do think you're way too overbearing.
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Quite frankly, kid, I don't give a hoot what you think of me. And your "honest opinion", as you claim, was stated as fact - not opinion!!

I am and always will be perfectly honest at all times. And here's a little more honesty for you - I don't care if you go down in the flames of ignorance. You aren't one of my students and I've seen a few much smarter than you fail completely. Sorry, but that just another dose of real life for you. The fact that most of us aren't one bit interested in what becomes of you or what you think of us. It won't affect my bank account one way or the other. :D
 
Yes, Light, every jerk who acts the way you've been acting always thinks that it's justified and they all have their own line of doubletalk. All you're doing is taking potshots.

Do you have any kind of test of whether Carnot efficiency is the limit of the efficiency of a heat engine? They always say "don't assume." Do we believe this thing because of actual experiment or untested theory? Are people even allowed to advertise that an engine exceeds Carnot efficiency when in fact it does? And while we're at it, why does it seem so clear that a heat pump is more efficient than resistance heating when it is supposed to take more energy to pump heat uphill than to just generate the heat? It sounds like doubletalk to me.
 
MetaKron said:
Yes, Light, every jerk who acts the way you've been acting always thinks that it's justified and they all have their own line of doubletalk. All you're doing is taking potshots.

Do you have any kind of test of whether Carnot efficiency is the limit of the efficiency of a heat engine? They always say "don't assume." Do we believe this thing because of actual experiment or untested theory? Are people even allowed to advertise that an engine exceeds Carnot efficiency when in fact it does? And while we're at it, why does it seem so clear that a heat pump is more efficient than resistance heating when it is supposed to take more energy to pump heat uphill than to just generate the heat? It sounds like doubletalk to me.
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Sigh.

You really don't know much about mechanics, do you?

Just do even the tiniest bit of research on heat pumps and the answer will jump right out at you! It's because they use that energy to extract the heat form an external source (air or water) and concentrate the heat delivered. Have you ever heard of the term "Coefficient Of Performance?" It's a direct measurement of the energy supplied to the amount delivered. In the case of a heat pump, the COP will easily run 3.0 to 4.0. That means for every watt of electrical energy supplied to the pump - for which you'd only get a single watt of heat in a resistance heater - there's actually three or four watts of heat delivered at the output. Doubletalk? Hardly.

You really, really, really need to study more before you even open your mouth again. You just keep digging yourself in deeper.
 
Light said:
Sigh.

You really don't know much about mechanics, do you?

Just do even the tiniest bit of research on heat pumps and the answer will jump right out at you! It's because they use that energy to extract the heat form an external source (air or water) and concentrate the heat delivered. Have you ever heard of the term "Coefficient Of Performance?" It's a direct measurement of the energy supplied to the amount delivered. In the case of a heat pump, the COP will easily run 3.0 to 4.0. That means for every watt of electrical energy supplied to the pump - for which you'd only get a single watt of heat in a resistance heater - there's actually three or four watts of heat delivered at the output. Doubletalk? Hardly.
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So you are saying that heat pumps deliver far more than unity gain, even counting losses in the cycle. You said in exactly that many words that a machine that is on the market uses one watt to move up to four watts of heat uphill. I think it's doubletalk. It violates physical laws that you would use to claim that there is no way to use ambient heat to generate useful energy and that Carnot efficiency is the end of the story. Prove your claim.
 
Tirstan said:
What are the limiting factors involved in engine technology?
Specifically, I am wondering why we are still using big old engines. Just easier to work with what already works?

Development: First came gas otto cycle, then came diesel. Diesel is more efficient since the combustion is more complete due to the higher ignition temperatures. The major difference between gas and diesel (besides one uses gas and the other diesel) is in the compressed mixture and the igniting of the mixture. Gas mixes fuel and air at the carb or intake. The mixed fuel and air is compressed then ignited to preform the work of moving the piston which transfers the power to the crankshaft driving the flywheel, transmission, then wheels. Diesel draws air into the cylinder. The air is compressed raising the temperature of the air to over 400. Fuel is then sprayed into the cylinder where it instantaneously combusts. This process makes it possible to run the engine off vegetable oil. Von Diesel originally designed the engine so farmers could grow their own fuel(soybean oil).
Gas has won over diesel because until recently the diesel engine's higher compression ratios required a much thicker engine, making it much heavier, the power to weight ratio of the gas engine made it a much more attractive engine. However recent advances in materials has enabled light diesel engines(Golf TDI).

Inefficiencies of the engine: the transfer of power to the crankshaft and other parts, and this is the one that interests me the most LOSS OF HEAT

Why do we waste this heat? Can we not use the heat to create steam to drive turbines? Why use pistons at all? Why not just add fuel to an enclosed chamber (spherical) then ignite it. If the sphere was strong enough not to explode from the force would it not transfer the energy of the ignition into heat which could then be used to heat water driving a steam turbine. Locomotion would be accomplished by electric motors. What are the inefficiencies involed with electric motors?

Any thoughts? I realize the sphere would have to be able to blow off extreme pressure to prevent a possible explosion. Why is steam a bad idea?
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A lot of the reason we waste heat from a gasoline engine is because recovering it and using it requires bulky, expensive, and complex equipment. We are better off throwing it away than we are adding that much more gear to the inside of the engine compartment. Even scavenging fuel vapors from the exhaust is fairly hard to do and it adds one more risk factor to the use of gasoline engines.
 
MetaKron said:
So you are saying that heat pumps deliver far more than unity gain, even counting losses in the cycle. You said in exactly that many words that a machine that is on the market uses one watt to move up to four watts of heat uphill. I think it's doubletalk. It violates physical laws that you would use to claim that there is no way to use ambient heat to generate useful energy and that Carnot efficiency is the end of the story. Prove your claim.
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Good grief - it's not my claim! How can you be so silly? They have been marketed for years because they work so well at saving energy. I've even installed one of them myself - actually did all the work with the help of one other fellow.

As I've said to you several times already, you need to actually READ before you speak! Here's a brief (so it won't kill your short attention span) article that even explains the math involved (but you'll probably have to get some one to explain the math to you). http://en.wikipedia.org/wiki/Heat_pumps

Tell you what, I'll make a deal with you. If you'll restrict yourself to just asking questions - and thereby actually learn something (maybe!) instead of trying to act so "smart" (and completely blowing it), I'll get off your case and be one of those that provides you with straight and honest answers. Deal?
 
It's doubletalk. It is impossible to push energy uphill without expending more energy than you move. Also, you forgot to link to the article you promised. OK, I see it now. Wasn't there before.
 
MetaKron said:
It's doubletalk. It is impossible to push energy uphill without expending more energy than you move. Also, you forgot to link to the article you promised. OK, I see it now. Wasn't there before.
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Yes, I accidentally posted it before including the link but corrected it quickly.

After you've read it, come back and tell us what you've learned.
 
Light, the article you linked me to entirely fails to explain how a heat pump produces any advantage over resistance heating. The mathematics in the article are only good for estimating the COP from observed hot side and cold side temperatures and nothing else. The fact that a heat pump compresses a working fluid is a given. You need to supply more information if you expect a person to understand or even believe a COP greater than one.

I have doctrine firmly behind me on this one. Because of the laws of thermodynamics, I have to presume that compressing the working fluid takes as much energy as we can "extract" from that same working fluid. The volume does not change because we pour it into a taller, narrower vessel.

Did you actually read the article, Light?
 
And furthermore, on top of that: The math in the Wiki article does not include any proof that it can be legitimately used to estimate COP because it does not include any value for the actual work expended to raise or lower the temperature of the working fluid. Try again, Light.

The one over the Carnot cycle efficiency is priceless. Carnot efficiency is never greater than one, so one over that number is never less than one. All you have to do to get overunity is to turn the equation upside down. How come I never thought of that?

I think you've given me something useful here but I don't know if it is something I can use, and if I can use it I don't know that it won't get me shot.
 
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MetaKron said:
Light, the article you linked me to entirely fails to explain how a heat pump produces any advantage over resistance heating. The mathematics in the article are only good for estimating the COP from observed hot side and cold side temperatures and nothing else. The fact that a heat pump compresses a working fluid is a given. You need to supply more information if you expect a person to understand or even believe a COP greater than one.

I have doctrine firmly behind me on this one. Because of the laws of thermodynamics, I have to presume that compressing the working fluid takes as much energy as we can "extract" from that same working fluid. The volume does not change because we pour it into a taller, narrower vessel.

Did you actually read the article, Light?
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Yes, I read it.

I must say that I've run across a few boneheads in my 60+ years but never one that seemed to want to make a career out it as you seem to.

The fact that they've been selling these things for over forty years doesn't even give you clue??? Do you somehow think that all those millions of people, businesses and industries were tricked into buying something that didn't even work as it was claimed???

Man! After reading this and your next post, I'll have to downgrade your status to something considerably less than just "dummy!" That term is far to generous for you.

Thing is, there are several other people here who also know exactly how heat pumps work. As soon as they read what you've said they will all be laughing their heads of at you! What a dope! :D
 
MetaKron said:
Like I said, Light, it looks like you have you some growing up to do.
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Ha-hah-ha!

Hardly - look who's talking!

Just how old are you, anyway? Maybe 15 at the most? And don't say it doesn't matter because it really does. At that age or less, we can understand. But if it's over that, well...
 
I understood the mathematics quite well. It would have helped if someone had explained that the "A" stood for the amount of energy input into the heatpump, presumably the portion that is power supplied by the user to push the heat around. The thing is, you still have the Carnot equation upside-down and you don't blink an eye when it gives upside-down results. The equation in that page you linked to cannot give any result less than 1. It cannot give an output to input ratio of less than one. All of this is quite explicit. You have no call to call me "dummy." I don't know what planet you live on where you think that is appropriate.

So what we have here is "Light" telling me that you can get 4 watts of heat out of a heat pump per watt that you supply as power, and that this is because of the mathematics at this Wikipedia page. Then he calls me a dummy because I point out what is glaringly obvious. Here is the Carnot Equation (scan down the page) for comparison.

The mathematics describe a situation that is exactly as if a heat engine that is 25 percent efficient at producing mechanical energy will, if reversed, become 400 percent efficient at transporting heat energy uphill by applying mechanical energy. It is exactly what Light has claimed, and the entire industry claims. It satisfies a type of mathematical symmetry. It is also impossible according to the laws of thermodynamics. It is supposed to take at least as much work to push a given number of BTUs uphill as you would get out of those BTUs, no exceptions. If someone wants to challenge that, please do. It is supposed to be one of those crackpot claims that no one is ever supposed to believe, that you can use some kind of tricks to get heat to go uphill without expending a lot of excess energy. So, in theory it can't work at all. Experimental evidence shows that it does work. This is what I've been trying to get at all night.
 

Here's another little tidbit for you to think about. Do you also suppose it takes more electricity (energy) to pump gasoline/petrol from the tank in the ground up into your car than you get from the fuel when you drive your car?

It's very similar in that the heat pump expends energy gathering additional energy and pumping it indoors. A very large portion of the energy used by the pump is simply lost - but it more than makes up for that with what it collects from the surrounding air or water.

The environment actually contains a LOT of heat, just at a lower intensity. The heat pump collects and concentrates that. Your mistake is that you are apparently supposing that the claim is that you put electrical power into the unit and it somehow "magically" is producing more than you supplied. And that's not the situation at all - it has a tremendous reservoir of external heat to draw upon.

But I suppose you won't understand that either, eh? :rolleyes:
 
It doesn't matter what size the tremendous reservoir is. That's a fallacy used by people who promote obvious violations of the 2nd law. The analogy of the gasoline pump is a false analogy. You're making the same claims that a lot of the promoters of perpetual motion make. The fact that these claims seem to be testable and true doesn't change their content.

I understand that when I want to build a heat engine using hot water I am told that I can't turn even a substantial percentage of the heat energy in that water into mechanical energy. Then I'm told that it's exactly backwards with heat pumps. That's what the equations say. The Carnot equation says that you can't get more than unity. The heat pump equation says that you can't get less than unity. Experimental evidence says that you can get at least four times unity.

How about facing down the equations and the evidence? Try not to call names.

Again: The objection to super-efficient heat engines is that you can't get more than the Carnot efficiency. No matter how large your reservoir is, it is only so deep.
 
MetaKron said:
I understood the mathematics quite well. It would have helped if someone had explained that the "A" stood for the amount of energy input into the heatpump, presumably the portion that is power supplied by the user to push the heat around. The thing is, you still have the Carnot equation upside-down and you don't blink an eye when it gives upside-down results. The equation in that page you linked to cannot give any result less than 1. It cannot give an output to input ratio of less than one. All of this is quite explicit. You have no call to call me "dummy." I don't know what planet you live on where you think that is appropriate.

So what we have here is "Light" telling me that you can get 4 watts of heat out of a heat pump per watt that you supply as power, and that this is because of the mathematics at this Wikipedia page. Then he calls me a dummy because I point out what is glaringly obvious. Here is the Carnot Equation (scan down the page) for comparison.

The mathematics describe a situation that is exactly as if a heat engine that is 25 percent efficient at producing mechanical energy will, if reversed, become 400 percent efficient at transporting heat energy uphill by applying mechanical energy. It is exactly what Light has claimed, and the entire industry claims. It satisfies a type of mathematical symmetry. It is also impossible according to the laws of thermodynamics. It is supposed to take at least as much work to push a given number of BTUs uphill as you would get out of those BTUs, no exceptions. If someone wants to challenge that, please do. It is supposed to be one of those crackpot claims that no one is ever supposed to believe, that you can use some kind of tricks to get heat to go uphill without expending a lot of excess energy. So, in theory it can't work at all. Experimental evidence shows that it does work. This is what I've been trying to get at all night.
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No. At this point I've had quite enough tonight of your unwillingness to learn. I may return later but in the meanwhile someone else can try cramming real information into your dense head. You think you know the answers? Fine - live with them.

And since you didn't see fit to reveal your age, I gather you're just a stupid know-nothing young punk. Not worth wasting my efforts on.

Goodnight.
 
You know, Light, you have entirely failed to make it believable tonight. I don't think that anyone over the age of 15 is falling for it, even after you've broken your chalk and thrown the eraser to the back of the room.
 
Wikipedia article


The way it's always been explained to me, if the Carnot formula says the engine efficiency is 10 percent, that means that the engine produces a power output that is equivalent to 10 percent of the energy that is available. The energy that is available is proportionate to the difference between the Kelvin temperatures of the hot side of the engine and the ambient temperature. So I've been told that such a setup gives me 10 percent of that ten percent. The general presumption is that you would start with a working fluid like water at ambient temperature, raise its temperature using some kind of heat source, and convert that heat to other kinds of energy like mechanical energy or electricity. The only heat that is available is that part that is above the ambient temperature. If your hot side is 330 K and your ambient is 297k, only ten percent of the hotside temperature, the hotside heat content, is available. The Carnot equation expresses efficiency as a percentage of the hotside temperature, and it does say hotside over ambient. Your engine can use all of the available heat and still be rated at 10 percent efficiency by that standard. The maximum possible utilization of the heat energy is rated at 10 percent instead of 100 percent heat efficiency. Then they tell you to only expect 10 percent of that 10 percent, so the best heat engines theoretically possible can allegedly only give you one watt of work for every ten watts of heat put into them.

I don't know. I always felt like if an engine used all of the energy available to it, it worked at 100 percent efficiency, giving ten watts of work for ten watts of heat input, and so on. I've also always felt like the only energy available from a heat source was in that part that was more than the ambient temperature.
 
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