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Post by GTCGreg on Nov 19, 2012 16:25:02 GMT
Not considering any "line loss" in delivering the power, it was the general consensus that an electric heater was virtually 100% efficient. Heat pump based electric heaters are over 300% efficient. Yes, you get over 3 times more heat energy out then you put in through electrical energy. That extra energy does come from somewhere though. It comes from the temperature of the outside air. But as far as your wallet goes, it's free energy. Unfortunately, heat pumps do not work well in all climates.
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Post by the light works on Nov 19, 2012 16:28:57 GMT
Not considering any "line loss" in delivering the power, it was the general consensus that an electric heater was virtually 100% efficient. Heat pump based electric heaters are over 300% efficient. Yes, you get over 3 times more heat energy out then you put in through electrical energy. That extra energy does come from somewhere though. It comes from the temperature of the outside air. But as far as your wallet goes, it's free energy. Unfortunately, heat pumps do not work well in all climates. that's a bit of a misstatement: heat pumps can heat your home 3 times more efficiently than resistance heating, but that does not make them 300% efficient.
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Post by GTCGreg on Nov 19, 2012 16:44:27 GMT
that's a bit of a misstatement: heat pumps can heat your home 3 times more efficiently than resistance heating, but that does not make them 300% efficient. True. From strictly an engineering standpoint, the term you would want to use is coefficient of performance (COP). Since most people aren't engineers, and are only interested in what comes out compared to what was paid for going in, the term efficiency is appropriate.
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Post by the light works on Nov 19, 2012 16:48:28 GMT
that's a bit of a misstatement: heat pumps can heat your home 3 times more efficiently than resistance heating, but that does not make them 300% efficient. True. From strictly an engineering standpoint, the term you would want to use is coefficient of performance (COP). Since most people aren't engineers, and are only interested in what comes out compared to what was paid for going in, the term efficiency is appropriate. which is why it's even more important to use terminology consistently. otherwise they'll be trying to get free energy with heat pumps and thermocouples.
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Post by GTCGreg on Nov 19, 2012 16:57:56 GMT
Any energy I got that I didn't pay for is "free" energy. Yes, it came from somewhere but it didn't cost me anything.
Not any point in arguing. We both know it's just semantics.
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Post by the light works on Nov 19, 2012 17:05:48 GMT
Any energy I got that I didn't pay for is "free" energy. Yes, it came from somewhere but it didn't cost me anything. Not any point in arguing. We both know it's just semantics. but it's the same sort of semantics that result in someone arguing that a slinky cannot go down an up escalator indefinitely, because that would be perpetual motion.
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Post by GTCGreg on Nov 19, 2012 17:28:47 GMT
Any energy I got that I didn't pay for is "free" energy. Yes, it came from somewhere but it didn't cost me anything. Not any point in arguing. We both know it's just semantics. but it's the same sort of semantics that result in someone arguing that a slinky cannot go down an up escalator indefinitely, because that would be perpetual motion. I don't see it being the same at all, but if you think so...
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Post by the light works on Nov 19, 2012 20:12:10 GMT
I do think so, the same way I am conscientious to differentiate "free-to-me" energy, which is possible, from free energy, which violates the laws of thermodynamics.
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Post by GTCGreg on Nov 19, 2012 20:47:53 GMT
Well I have to admit that I haven't been following the slinky threads very closely. It there's a connection between slinky's, electric heaters, heat pumps, efficiency and COP, I didn't see it. I guess I'll have to pay closer attention.
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Post by the light works on Nov 19, 2012 21:05:21 GMT
the connection is in people who confuse terminology. I would expect it to be patently obvious that a slinky on an up escalator is not any sort of over unity device, and it is clear to us that a heat pump is also not an over unity device; but there will be those who get confused.
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Post by GTCGreg on Nov 19, 2012 21:15:51 GMT
I sure didn't mean to confuse anyone. I thought my first post was really clear on the topic. I think I made a point of explaining where the energy was coming from and exactly why I considered it free.
"Heat pump based electric heaters are over 300% efficient. Yes, you get over 3 times more heat energy out then you put in through electrical energy. That extra energy does come from somewhere though. It comes from the temperature of the outside air. But as far as your wallet goes, it's free energy."
What part of that confuses you into thinking I'm talking about perpetual motion or any such rubbish?
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Post by the light works on Nov 19, 2012 21:23:10 GMT
I sure didn't mean to confuse anyone. I thought my first post was really clear on the topic. I think I made a point of explaining where the energy was coming from and exactly why I considered it free. "Heat pump based electric heaters are over 300% efficient. Yes, you get over 3 times more heat energy out then you put in through electrical energy. That extra energy does come from somewhere though. It comes from the temperature of the outside air. But as far as your wallet goes, it's free energy."What part of that confuses you into thinking I'm talking about perpetual motion or any such rubbish? I could tell you weren't, but someone else may have seen the "300% efficient" part and leapt to conclusions.
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Post by GTCGreg on Nov 19, 2012 21:34:59 GMT
You're right. And now I see the connection to the slinky thread. But is there really any hope for such people? I guess we still should try. It's on to the Carnot cycle. There, that should do it! A heat pump in pretty pictures.
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Post by the light works on Nov 19, 2012 21:44:10 GMT
no, there frequently isn't hope for such people. think of all the variants of overbalanced wheels out there.
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Post by WebDragon on Nov 20, 2012 1:51:23 GMT
I don't recall that particular exchange. I think I recall a similar exchange in which someone suggested that some of the emissions would escape through the window as photons and leave our atmosphere without being converted to heat. But I'm curios about what part of your exchange blew your mind? I thought that was in a conversation about whether all energy ultimately ends up as heat. You're likely right about that. I wasn't sure about it being Spork, though it's apparent now that it wasn't. What "blew my mind" was that I overlooked something so seemingly obvious. I actually thought I had a good argument about the acoustic "waste" but didn't follow the path far enough to realize that the energy would ultimately become heat. I don't mind at all being wrong now and again, provided I learn something from it.
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Post by GTCGreg on Nov 20, 2012 2:30:01 GMT
I don't mind at all being wrong now and again, provided I learn something from it. Well, you aren't really completely wrong here. While, for practical purposes, just about all energy ends up as heat there is still some energy that can end up as mass. In a particle accelerator, such as at CERN's, energy is sometimes converted to mass in the form of new particles, along with their corresponding anti-matter particles. At the edge of a black hole, energy is also converted to mass causing matter and antimatter to be expelled. Not that you're likely to see that in your kitchen, but not all energy ends up as heat.
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ronbo6
Demi-Minion
Survivor: End of the World. 12/21/2012
Posts: 91
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Post by ronbo6 on Nov 20, 2012 5:49:53 GMT
From the following website www.phys.unsw.edu.au/~jw/FAQ.html#massMass Defect " If you supply say 100 kJ to a kettle full of water by heating it at 1 kW for 100 seconds, this energy increases the mass of the water by 100 kJ/c2 = 1 ng." It is something I have always found interesting, so its not only happening at cern its happening to your coffee and by the same token, the mass of the gases leaving the exhaust pipe of a car is less than the mass of the air and fuel input (when you discount or otherwise account for things like burned lubricant and cylinder blowby) by the amount of energy liberated by the fuel's combustion.
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Post by silverdragon on Nov 20, 2012 7:46:54 GMT
I think it was Spork (ziploc) who suggested that the miniscule audio component will eventually dissipate into heat. Blew my mind. Erm... he was wrong?.... Sound is energy, yes, but it is sound, and not heat.?.... This may get into "If the tree falls in the wood and no one is there will it make a sound" thing, but if that hum escapes the room, its "Loss"?... Electricity 100% (Or near enough to that) efficient, Do we buy that?... I dont. Is The waste of turning fossil fuel and other energy sources into electricity is still to be accounted for?... "Line loss" in transferring the power to your house... Ok, so, hows about a thought experiment. Take two logs. One gets turned into electricity by the most efficient biomass generator you can find, the other goes into the fireplace, and how long will the room be heated....... Its well known that if they use Oil powered generators, an Electric Car will use MORE oil to get 100 miles than the equivalent IC engine car. Personally, Give me the log, I would prefer a real fire, but we aint allowed to make Smoke round here because of local anti-pollution laws... I got shouted at for that one time by "inspectors" for making smoke out the chimney... Egg on Face time when it was revealed I was steam cleaning the chimney to put a new liner in.
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Post by wvengineer on Nov 20, 2012 16:57:25 GMT
One thing I find is that it can help to simply engineering terms. Therms like COP or efficiency can confuse people who are not familiar with their proper use. Instead of calling a heat pump a heat producer, it is better to call it use descriptions that the average public is more familiar with. For example, you call a heat pump a device that moves heat from one location to another. that helps you average person understand how they work better than throwing around the CoP of the system.
Put stuff in everyday terms.
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Post by the light works on Nov 20, 2012 17:03:31 GMT
"Electricity 100% (Or near enough to that) efficient, Do we buy that?... I dont. Is The waste of turning fossil fuel and other energy sources into electricity is still to be accounted for?... "Line loss" in transferring the power to your house...
"
but it is more efficient to route the electricity through a resistance heater to generate heat than it is to route it through a grow light to grow a tree to burn in your fireplace. and in this case, the efficiency we were talking about was the efficiency of a resistance heater in converting electricity into heat. - not the efficiency of the generation source.
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