*Sorry a heatpump (HP) cannot have a COP 30 or 60* Sorry but they can, I gave you the links.
The math also supports this. No, you are right that a regular small house-hold heatpumps operating at 100% power over the rated temperature differential will top out currently at about a heating COP of 5.5. However is it is well made and can be powered at the ideal power level the COP goes up and can be measured at 10+ And that is just the heat being counted, if we count the cold side which is normally ignored when we are trying to heat we get a true COP of 20+ But have you ever wondered who small house-hold heat pumps have a higher COP than larger ones? It is because the smaller heatpumps have everything (for the power level they work at) size larger and closer to optimal. But when operating on an inverter basis, the efficiency can go higher. And the COP of a larger heatpump that isn't working hard out can exceed the rated COP of a smaller heatpump and even outclass it entirely, though there might also be a point of something being oversized but I don't really think it's much of an issue when it is inverter based and you know how inefficient it is to have the cold side outside to have a hard time due to getting too cold and frosting up too much... Note: "A W10W35 water-to-water heat pump should have a coefficient of performance (COP) of at least 5.5. COP" AT LEAST! not at best. I just asked a chatbot, apparently 12.8F might be a plausible range to give a reading over: " 47°F (8.3°C) outdoor temperature and 70°F (21°C)" So I ran with that and based on the heat engine efficiency numbers, at that temp there is a 4.3% efficiency as a heat engine, and that would seem to indicate an absolute max heatpump COP of 29. But at a 2C difference it was a heat engine efficiency of 0.67% and a COP as high as 148! People report to have measured COP's of 11, and I gave you links to very professional examples of COP's up to 30 and explain why 30 can be seen as 60 when you utilize both sides. In theory COP can with some tiny fraction of a C separation across each heatpump go near infinite if ideal (no losses). Of course if you were driving so many you would need to find a super efficient way, but we don't need a COP of 148 even if it is theoretically possible. A COP of 5.5 even without doubling it is plenty, even without running it across a more modest gradient... Just run enough in series to get the efficiency of the heat engine to about 50% while the COP is not much worse than 3 and you not only have a proof of principle but something perhaps practical. But we don't need to build it, the fact is that in theory you can move ANY amount of heat up any hill as long as it is divided up by enough heat pumps that have low frictional losses. We don't need to build it (though we could) to prove that the conservation of Energy is more of a rule of thumb but easily broken in practice if you know how. *Assume a COP of 5 for a single step HP as we have it today in a reasonably good probe heat pump. (mine has 5.5 for heating)* Ok. Can do. *You can neither simply multiply or add the COP's* I did neither one, well I doubled which is valid (or approximately so) in a single state if you just count the cold side, but generally I didn't add or multiply COP's. *as you must provide e.g. 20x the basic energy to fill the reservoir for the next HP state.* There are probably only 2 Reservoirs (one on the extreme hot and extreme cold ends), and even if there is a reservoir between each one it only takes a moment to reach a steady state condition and then it is as if it isn't there. I am not sure really what you are talking about, what reservoir needs 20 times the energy? I think you have misunderstood something. What we are proposing is very much like Carnot's proposal, 2 Reservoirs, one hot and one cold. There is a high efficiency heat engine connected between two reservoirs turning say with 64% efficiency of the thermal energy to mechanical. If we were to try and make this heat engine drive another identical heat engine connected between the same 2 resivious to act as a reatpump it would fail as each would be matched, even If it was smaller and weaker but just as efficient as a heat engine then as a heatpump over that temperature differential it would have a COP of less than 1 if I'm not mistaken, but not good anyway. However if we had multiple identical reversible heat engines, and one goes between the hot and cold, and the others are placed with one on one hot, one on the cold and other heat engines placed in between. As such they would behave just like a series of resistors across a voltage potential. If you measured the temperature between each one it would ideally be a fraction of the total. Each one by being over a tiny fraction of the full temperature differential is only driven as a heat engine very weakly (low efficiency) that can easily hit a percent or 2 or less. And a 2% efficient heat engine when run as a heat pump has a huge COp. I really don't understand what you are imagining "*20x the basic energy to fill the reservoir for the next HP state" but I have been veyy careful to be easily comprehensible.* So, I ran it by a LLM, it didn't understand you either. more below... Based on the statements provided, it seems there is some confusion or lack of clarity in the explanation being given. Here are a few observations: 1. The statement about needing to "provide 20x the basic energy to fill the reservoir for the next HP state" is unclear. There doesn't seem to be enough context to understand what is meant by "HP state" or why a factor of 20 would be involved. 2. The example about heating 1000L of water from 10°C to 50°C and needing 25,000L at 10°C if taking out 2°C appears to be referring to the amount of heat energy required, but it's not clearly connecting this to COP calculations. 3. The statements about the "base COP" going in with a factor of 20 and dividing 25 by 20 for a first second step don't have enough explanatory context to make sense on their own. 4. The final statement "initial total COP = 5 + 25/20" seems to be arbitrarily combining numbers without a clear derivation. Without more context about what specific system is being analyzed and what assumptions are being made, it's very difficult to decipher the meaning behind these statements. They don't seem to follow any of the standard analyses for calculating heat pump or heat engine COPs based on temperatures and energy inputs. It's possible there is some valid point being made, but the explanation lacks crucial details and derivations to make the logic clear and followable. More contextual information would be needed to try to interpret these statements accurately. * To heat 1000l from 10 to 50C you need 25'000 Liter of water at 10C if you take out 2C. * I'm not going to challenge this claim, at least I understand what you are saying, but it has no relevance. The goal is not to have any net increase in temp, actually if all things go as planned the heat pump would have potentially no actual heat output and would just power itself and produce excess power for the grid making the world a bit colder. The idea is the heatpump moves heat from one reservoir to the other. You can think of the heatpumps being like a chain of men passing buckets of water to put out a fire, each heatpump moves every joule of heat from one end as it passes it on to the next. Each only moves the bucket of water a tiny distance (each only moves the joule of heat up a tiny temperature gradient of 1-10 degrees C). Water is moved from one reservoir and poured into the other (thermal energy is removed from one revivior and put into the other). One reservoir ends up hot, and one ends up cold, one reservoir is overfull the other is very low. A heat engine (steam turbine?) converts the thermal energy to mechanical energy, enough to drive the heat pumps and more. Or a water wheel converts the energy. Done right the hot and cold reach an equilibrium with the load and the heatpumps and with the apparent exception that I believe it is meant to be colder, it will just output power, if not it would also break the first law. *So the base COP goes in with a factor 20 in the total COP equation.* *Thus you must divide 25 by 20 for a first second step. In average by 10. Thus initial total COP = 5 + 25/20!* So lost, no idea what you mean. Each heatpump is doing the same job, or each heat engine is doing the same job with total ignorance that there are other inline with it, If a heatpump is operating over a temperature and power range in which it's COP is 10, it's COP is 10 and it doesn't matter at all if the heat is drawn away by another heat pump, or the cold side warmed up by another heatpump, as long as it is within the range at which it provides as 10 times more heat than you put in then that's what it does. There is no modification needed of the COP, other than to realize that heat pumps normally only count half the output at a time (hot OR Cold, never both), and normally are not rated for their maximum COP, but a reasonable average COP. PERHAPS the MVR ones I mentioned were in fact talking about the both outputs but I don't think so but can't be sure and whatever, it doesn't change the validity of my argument and just how dead the second law is. Once that is accepted then practical engineering can be considered. *Also the cooling does only count if you can use it. Normally in winter you must heat. * Sure, but I'm not talking about such conditions. I am talking about a dedicated and initially theoretical device that makes a hot and cold side and drives it's own heatpumps. As such the cold side is very valuable as it hugely increases the efficiency, at least of the heat engine. *The optimal solution would be to combine the fridge with a heat pump but a good fridge today uses only 300W/day....* A fridge though ok is hardly optimal. We want AS MANY stages as we can practically do, 5 is the low end, 20 would be perhaps a decent tradeoff, but if I was trying to do this well and make it a bit custom I'd try and have 100 heatpumps in series. This them means each one can have a 5C uplift (temperature differential) and we can have at least a 500C difference between the hot and cold side, this is actually like a heatpump with a 2.5C uplift from ambient, so maybe 10C is doable for a 1000C difference, or maybe if that much worked, what's another 100!, I would not bother going for 1000 or anything even if it was some custom solution, at least not unless it was clearly all best but I'd think it overkill. But the point is that the less each ones works to increase the temperature the greater efficiency they do (whatever little they do each) at, in theory to the point of infinitely many heatpumps in series moving infinite energy with no power input (only, not quite obviously). Jonathan On Fri, 10 May 2024 at 21:35, Jürg Wyttenbach <ju...@datamart.ch> wrote: > Sorry a heatpump (HP) cannot have a COP 30 or 60. Assume a COP of 5 for a > single step HP as we have it today in a reasonably good probe heat pump. > (mine has 5.5 for heating) > > You can neither simply multiply or add the COP's as you must provide e.g. > 20x the basic energy to fill the reservoir for the next HP state. To heat > 1000l from 10 to 50C you need 25'000 Liter of water at 10C if you take out > 2C. > > So the base COP goes in with a factor 20 in the total COP equation. > > Thus you must divide 25 by 20 for a first second step. In average by 10. > Thus initial total COP = 5 + 25/20! > > Also the cooling does only count if you can use it. Normally in winter you > must heat. The optimal solution would be to combine the fridge with a heat > pump but a good fridge today uses only 300W/day.... > > > > J.W. > On 10.05.2024 03:49, Jonathan Berry wrote: > > Not sure why but this isn't forming into proper paragraphs... > > > *"Youtube physics usually is self satisfaction of people that have no clue > of the simplest things. So I almost never watch this garbage."* > The video is covering the work of a company cascading heat pumps. > As such the temperature differential over each heat pump is a fraction of > the total over all the heatpumps, there is a potential feedback instability > effect they have resolved. > > But cascaded heatpumps are an accepted thing with improved COP over a > given total temperature difference and the video isn't making claims about > the second law, that's me, and well Carnot... > > *"A heatpump is not a Carnot process as you obviously supply additional > energy!"* > > It is a carnot process though and the carnot process gives us the > efficiency limit. > > A reversible heat engine if you supply it with kinetic energy can generate > a temperature differential, this is why it is called reversible, you don't > get energy from it, you reverse it and put energy in to move heat. > > To do this you obviously need to supply it with energy just as we do with > a heat pump. > > *"You must calculate in the Carnot conversion rate of energy gained --> > electricity to get the proper conversion factor as the current for the > heatpump must be produced too and subtracted!"* > > Yes, however the COP of a heat pump (electrical power in .vs heat energy > gain on the hot side) over a low temperature differential can be 5, 10, or > 30 or potentially more if the temperature differential is low enough. > > Note that in a single stage heatpump we can actually double that COP by > just counting both the hot and cold outputs as both being beneficial > outputs! > > If a heatpump can deliver four times more thermal energy than the power > going in (and for now assuming the heat from the input power is not seeping > inside) then wit has a COP of 4, but we ignore the cooling COP of 4 on the > other side, that is "free cold" and in terms of a temperature differential > to put a heat engine on both are sources of energy, but between the hot and > cold sides is a higher conversion efficiency than between the hot and > ambient and the cold and ambient. > > Which is the point I am making, if you divide the heat potential the COP > of the heat moving ability of a heat engine or heat pump it improves > relative to the energy it takes to drive it. > > > *"The best Carnot process (multi stage turbines) today delivers a > conversion rate of about 61% always target is current."* > > 61% is a fine conversion of heat to to energy since heatpumps can manage a > COP of 30! > > https://www.sciencedirect.com/topics/engineering/recompression COP > 30 "typically COP of 10–30 can be achieved" with a MVR heatpump. > > https://www.gea.com/en/assets/304829/ COP 20 > > You can have 30 times more heat energy moved and that's just looking at > the heat energy gain, ignoring the energy below ambient on the cold side, > so with that a COP of 60!... > > Now granted my whole point is not that this if done with a single heatpump > it would not be efficient when you run steam turbines over 1C, 10C or so, > so it does not matter how well it was design, because to gain efficiency > for conversion of thermal energy we need as great a temperature difference > as possible, but there is no reason we can't put multiple heat pumps in > series each working over a small temperature range just as we put batteries > in series. > > And we can do the same with heat engines which are just Carnot heat > engines under a different name not designed to be reversible but > conceivably can be redesigned to be reversible. > > > And again, the point of this post is to point it out from the other > direction, according to Carnot if a reversible heat engine can be made more > or less efficient (while still not having frictional losses, poor thermal > insulation etc) then the second law would fail. > > And as putting two in series makes it less efficient (as Carnot would > himself assert if he had thought if it and apparently he managed not > to)... well then the second law fails, it CANNOT be true if this is a > reversible heat engine, AKA, a heat pump, as a less efficient heat engine > is a more efficient heat pump! > > That is the message of Carnot's theorem, but another thing of Carnot's is > the equation that tells us the efficiency of a heat engine. > > η = 1 - Tc / Th > > We take the cold temp in Kelvin, divide it by the hot temp and then > subtract the result from 1 then multiply by 100 to get our efficiency in > percent. > > So at -200C on the cold side and -190C on the "hot' side we have, after > adding 273.15 K 73.15 K which we divide by 83.15 = 0.8797354179194227 > subtracted from 1 gives us a 0.12 which we multiply be 100 to get the > percent: 12% efficiency. > > Interestingly if we drop the cold side to 0.0001 K and the hot side to 10 > K we get 0.00001 which subtracted from 1 x 100 gives us an efficiency of > 99.99999%! At just 10C (K) difference! > > Just why the cold side being almost perfectly cold skyrockets the > theoretical conversion efficiency... I am not clear on. And this should be > called into question at another time, but I wonder if it is related to how > hard it is to pump heat from something almost at absolute zero looking at > it in reverse? IDK, but whatever. > > But if we have a more normal temp range for our 10C difference of 15C and > 25C then... > > 25+273.15 = 298.15 and 15+273.15=288.15 So 288 / 298 = 0.9664429530201342 > subtracted from 1 then x 100 = 3.4% > > Ok, staying at a middle temp of 20C... > > 70C (343K) hot side and 100 C/K colder at -30C or 243 K then 243/343 then > subtract from 1 and multiply by 100 for percent and we get 29.15% > > Ok, so by having 10 times more heat potential difference we have close to > 10 times more conversion efficiency at turning heat into energy. > > And by using 10 heat pumps each just contributing 10C difference between > their hot and cold side we have a COP that might be quite high. > > The heat pumps each feel a mechanical feedback at about the 3.4% level > (they have to input in theory 3.4% of the heat they move). > > 3.4 / 100 That is a COP of 29. > > So once we have a COP of 29 and the other way we have a conversion > efficiency of 29%. > > Even though this is the max theoretical conversion efficiency at this > temperature differential and not a real world value, the potential is > clear, we can put in 100W, get 2.9KW of heat and get 29% of that back so > 841W out! > > You can of course go further, but while for practical application the > maximum efficiency of a heat engine is important, and putting too many heat > pumps in series sounds absurd, we can just focus on the undeniable fact. > > That there is no way the second law of Thermodynamics is consistent with > what we know for an absolute fact. > > That a heat engine and heat pump (heat engine run in reverse) have VERY > different and inverse efficiencies over large and small temperature > differences. > > It is easy (in theory even if expensive) to put 2 or 200 (reversible) heat > engines in series to make them less effective as a heat engine and more > efficient as heat pumps. > > And you can still tap the difference between the hot and cold sides to > achieve a conversion efficiency in reality of above 50% > > And as the COP from a heat pump can be VERY high (30 and higher) it's only > an issue of making this practical, not a question of if it can be done both > in practice and in theory. > > *"But there have been some materials detected that can improve this > further like thermo (Peltier-) elements."* > > Well it is an interesting point that between every heat pump in the series > you could actually put a heat engine (which a peltier is really) and you > could get a little energy out, it won't really affect anything (a little > heat will be turned into energy but in this case it's not really lost, > that which is transferred is meant to be transfered. > > This allows us to gain little bits of energy, but it is not worth the > bother unless there is a suitable difference in temp, if it is 1C it's > pointless (but then the max theoretical COP is 274!) the energy from it is > negligible. > > Having said that there IS a way to do it, if you put a bunch of heat pumps > in series there is going to be on the hotter half of the heatpumps, after > the fluid giving up it's extra heat to the hot side and expanded it is col, > likely colder than the ambient. > > So let’s say we have a hot revivor at 100C (+273.15 = 373 K) and 0C (0 + > 273.15 K) so we 273/373 = 0.7319 subtracted from 1 = 0.268 x 100 = 26.8% > > Ok so 26.8% efficient. > > But from 100C to 50C we get an efficiency of 13.4% > > From 50C to 0 C we get an efficiency of 15.4% > > For an average of 14.43% with 2 heat pumps in series but 26.8 for 1. > > This then means the only issue is how many you need given the real world > issues. > > And I'm happy to discuss that, but first let's just basc in the (ironic) > warmth of entropy being reversible. > > > > Heatpumps are reverse Carnot engines and have a much higher COP in respect > to heat gained but *not to current gained!!!!!!!* > > Even more interesting are quantum level processes in nano particles where > one could achieve the doubling of IR photon energy by suppressing some > emission bands. This could be used in solar panels. > > J.W. > > On Fri, 10 May 2024 at 01:20, Jürg Wyttenbach <ju...@datamart.ch> wrote: > >> Youtube physics usually is self satisfaction of people that have no clue >> of the simplest things. So I almost never watch this garbage. >> >> A heatpump is not a Carnot process as *you obviously supply additional >> energy*! You must calculate in the Carnot conversion rate of energy >> gained --> electricity to get the proper conversion factor as the current >> for the heatpump must be produced too* and subtracted! * >> >> The best Carnot process (multi stage turbines) today delivers a >> conversion rate of about 61% always target is current. >> >> But there have been some materials detected that can improve this further >> like thermo (Peltier-) elements. >> >> >> Heatpumps are reverse Carnot engines and have a much higher COP in >> respect to heat gained but *not to current gained!!!!!!!* >> >> Even more interesting are quantum level processes in nano particles where >> one could achieve the doubling of IR photon energy by suppressing some >> emission bands. This could be used in solar panels. >> >> J.W. >> On 09.05.2024 14:39, Jonathan Berry wrote: >> >> After 200 years (1824) the second law of thermodynamics is disproven. >> >> https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodynamics) >> >> Simply Carnot argues that if the efficiency of a reversible heat engine >> was variable based on how it is made or the gases etc, then the second law >> of conservation would be broken. >> >> "A heat engine *cannot* drive a less-efficient reversible heat engine >> without *violating the second law of thermodynamics*." (excerpt from the >> Wikipedia article below the image) >> >> So what happens when you take 2 reversible heat engines and put them in >> series (one touches the hot side, one the cold side and they join in the >> middle with potentially a small thermal mass that is >> thermally equidistant to the hot and cold side)??? >> >> Well, we know what happens, according to Carnot! >> The lower the thermal potential the lower the efficiency at turning heat >> into mechanical energy and therefore the less mechanical energy is >> developed when driving heat (operating the heat engine as a heat pump)... >> Which is to say that with a lower temperature differential a heatpump >> operates with more efficiency. >> >> So a heat engine constructed to act like 2 or more reversible heat >> engines will break the conservation of energy. >> >> There is a company that is making cascading heatpumps which can keep a >> high COP over a much larger temperature differential. >> https://www.youtube.com/watch?v=wSgv5NwtByk >> >> The point is that it is absolutely possible to turn uniform ambient heat >> into electrical power and heating and or cooling with current technology... >> And it is easily explained in a way that cannot be denied, clearly 2 >> heatpumps cascading have a higher COP, same as saying clearly 2 reversible >> heat engines in series have a lower conversion efficiency and therefor a >> higher COP as a hatpump, precisely the scenario that made Carnot assert 200 >> years ago would destroy the second law of thermodynamics. >> >> Jonathan >> >> -- >> Jürg Wyttenbach >> Bifangstr. 22 >> 8910 Affoltern am Albis >> >> +41 44 760 14 18 >> +41 79 246 36 06 >> >> -- > Jürg Wyttenbach > Bifangstr. 22 > 8910 Affoltern am Albis > > +41 44 760 14 18 > +41 79 246 36 06 > >
