5 ms·

What is the COP of a heat pump operating against this temperature gradient?

Ndymium 3y ago
Quoting from their linked website: > Our heat pump can generate up to 3 times as much heat as a resistor, using the same amount of electricity. Though it doesn't mention the temperature at which this is achieved, only that the range is from 160 to 550°C.
- franckl 3y ago
  we published a calculator if you would like to dig deeper! https://airthium.github.io/airthium.com-calculator/ https://airthium.github.io/airthium.com-calculator/ The COP gets lower as the temperature difference increases as you can expect.
  - jbm 3y ago
    For those, like me, who didn't know this term: https://en.wikipedia.org/wiki/Coefficient_of_performance https://en.wikipedia.org/wiki/Coefficient_of_performance > The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work (energy) required.[1][2] Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs.
- inamberclad 3y ago
  That 'up to 3 times' is a very generic sounding Carnot cycle number. It's about the upper limit for heat pump performance, so it's not a very meaningful number IMO.
byteware 3y ago
the maximum is given by the carnot cycle, which has COP=T_high/(T_high-T_cold) so from room temp 25°C to 250°C it is 2.3, but this is the theoretical limit
- Ballas 3y ago
  Which is why for some pool heat pumps you get claimed numbers of around 9, with the fine-print that the air temperature has to be higher than the water temperature.
cornholio 3y ago
At 1000℉ (811K) the maximum achievable COP against an ambiental (300K) source is about 1.6, limited by the second principle of thermodynamics. And that's the absolute theoretical maximum, you would be happy to breakeven in practice. Unless you have access to waste turbine exhaust, geothermal water, solar collectors or something along those lines, I don't see any practical application where the marginal energy savings would recover the capital costs of the pump at 1000F. But hey, they have software modeling and venture financiers, so I'm sure they are not overselling it and it's all excellent and double plus innovative.
- franckl 3y ago
  You are correct, even though your last sentence wasnt necessary... Please consider a use case where an industrial user install a thermal storage like this one https://www.kyotogroup.no/technology https://www.kyotogroup.no/technology They may need CO2 free process heat at 400 ℉, and use a thermal storage at 800 or 1000℉. Our heat engine can pump more heat than resistive heating (heat pump mode) during charge. During discharge, it can convert heat to electricity from 1000F to 400F, and use that electricity to power a heat pump (and produce more heat). We can "magnify" the storage both ways. We don't need to go to 1000F soon, there are so many applications we can decarbonize along the way. We could lower the temperature and do cooling+heating at the same time for example.

Quoting from their linked website: > Our heat pump can generate up to 3 times as much heat as a resistor, using the same amount of electricity. Though it doesn't mention the temperature at which this is achieved, only that the range is from 160 to 550°C.

franckl 3y ago
we published a calculator if you would like to dig deeper! https://airthium.github.io/airthium.com-calculator/ https://airthium.github.io/airthium.com-calculator/ The COP gets lower as the temperature difference increases as you can expect.
- jbm 3y ago
  For those, like me, who didn't know this term: https://en.wikipedia.org/wiki/Coefficient_of_performance https://en.wikipedia.org/wiki/Coefficient_of_performance > The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work (energy) required.[1][2] Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs.
inamberclad 3y ago
That 'up to 3 times' is a very generic sounding Carnot cycle number. It's about the upper limit for heat pump performance, so it's not a very meaningful number IMO.

byteware 3y ago

the maximum is given by the carnot cycle, which has COP=T_high/(T_high-T_cold) so from room temp 25°C to 250°C it is 2.3, but this is the theoretical limit

Ballas 3y ago
Which is why for some pool heat pumps you get claimed numbers of around 9, with the fine-print that the air temperature has to be higher than the water temperature.

cornholio 3y ago

At 1000℉ (811K) the maximum achievable COP against an ambiental (300K) source is about 1.6, limited by the second principle of thermodynamics. And that's the absolute theoretical maximum, you would be happy to breakeven in practice. Unless you have access to waste turbine exhaust, geothermal water, solar collectors or something along those lines, I don't see any practical application where the marginal energy savings would recover the capital costs of the pump at 1000F. But hey, they have software modeling and venture financiers, so I'm sure they are not overselling it and it's all excellent and double plus innovative.

franckl 3y ago
You are correct, even though your last sentence wasnt necessary... Please consider a use case where an industrial user install a thermal storage like this one https://www.kyotogroup.no/technology https://www.kyotogroup.no/technology They may need CO2 free process heat at 400 ℉, and use a thermal storage at 800 or 1000℉. Our heat engine can pump more heat than resistive heating (heat pump mode) during charge. During discharge, it can convert heat to electricity from 1000F to 400F, and use that electricity to power a heat pump (and produce more heat). We can "magnify" the storage both ways. We don't need to go to 1000F soon, there are so many applications we can decarbonize along the way. We could lower the temperature and do cooling+heating at the same time for example.