4 ms·

Who says the apparatus has to be in the low atmosphere? What you cite are technical reasons, not thermodynamic. Thermodynamics doesn't disallow the situation,

Who says the apparatus has to be in the low atmosphere? What you cite are technical reasons, not thermodynamic. Thermodynamics doesn't disallow the situation, only technical reasons make it difficult. > Sometimes it's best to do the math before claiming stuff > I see that none of you have heard of Carnot efficiency Sometimes it's best to get off your high horse.

semi-extrinsic 12y ago
Alright, thermodynamics + not requiring magic (except the unicorns) then. Thermodynamics has everything to do with it; if it were not for the Carnot limit on heat pump efficiency, your proposed scheme for heat removal would work fine. If it were not for the Carnot limit, we would have no problem growing global energy consumption at 2-3% per year (i.e. exponentially) for a hundred more years. So, if you put your apparatus anywhere but in the low atmosphere, how do you expect it to pump heat from the low atmosphere (where the heat is)? I'm not on any high horse, but I'm surprised at how quickly people dismiss this problem as absurd. It's quite obvious if you know some engineering thermodynamics. I think people dismiss it out of cognitive dissonance, since they don't want another unfixable world problem.
- darkmighty 12y ago
  > I'm not on any high horse > people dismiss it out of cognitive dissonance Ok then. You are making a few claims: 1) Thermodynamics imposes a finite limit on the energy consumption on Earth; Sure, it might be necessary to build a fleet of titanic cooling towers to cool the atmosphere, I don't think we will ever need to do that; but thermodynamics doesn't forbid cooling Earth, hence your claim is false. That out of the way 2) The direct thermal output of power sources/uses is going to be a problem in the near future I claim that's also false. In fact, the burden of the proof should be yours when you make such a claim, but let me show why I believe otherwise: (approximate figure from wiki [1]) 142 PWh of energy was used worldwide. Solar irradiance is 340000 PWh. It would take almost 200 years of steady 3% growth (or a 240x increase in consumption) to even reach 1% of solar irradiance as internal heat. Even then, the impact of greenhouse gases massively overshadows that. On top of that, there's no activity requiring exponentially more energy, or evidence that we may continue expanding energy demand for hundreds or years. In fact, if you look at per capita energy consumption vs GDP [2], you can clearly see a saturation of energy needs. Once the developing nations reach this, it seems demand growth is going to slow down. Nothing physical ever maintains an exponential growth for too long. [1] http://upload.wikimedia.org/wikipedia/commons/b/bb/The-NASA-Earth%27s-Energy-Budget-Poster-Radiant-Energy-System-satellite-infrared-radiation-fluxes.jpg http://upload.wikimedia.org/wikipedia/commons/b/bb/The-NASA-... [2] http://www.withouthotair.com/c30/figure242.png http://www.withouthotair.com/c30/figure242.png

semi-extrinsic 12y ago

Alright, thermodynamics + not requiring magic (except the unicorns) then. Thermodynamics has everything to do with it; if it were not for the Carnot limit on heat pump efficiency, your proposed scheme for heat removal would work fine. If it were not for the Carnot limit, we would have no problem growing global energy consumption at 2-3% per year (i.e. exponentially) for a hundred more years. So, if you put your apparatus anywhere but in the low atmosphere, how do you expect it to pump heat from the low atmosphere (where the heat is)? I'm not on any high horse, but I'm surprised at how quickly people dismiss this problem as absurd. It's quite obvious if you know some engineering thermodynamics. I think people dismiss it out of cognitive dissonance, since they don't want another unfixable world problem.

darkmighty 12y ago
> I'm not on any high horse > people dismiss it out of cognitive dissonance Ok then. You are making a few claims: 1) Thermodynamics imposes a finite limit on the energy consumption on Earth; Sure, it might be necessary to build a fleet of titanic cooling towers to cool the atmosphere, I don't think we will ever need to do that; but thermodynamics doesn't forbid cooling Earth, hence your claim is false. That out of the way 2) The direct thermal output of power sources/uses is going to be a problem in the near future I claim that's also false. In fact, the burden of the proof should be yours when you make such a claim, but let me show why I believe otherwise: (approximate figure from wiki [1]) 142 PWh of energy was used worldwide. Solar irradiance is 340000 PWh. It would take almost 200 years of steady 3% growth (or a 240x increase in consumption) to even reach 1% of solar irradiance as internal heat. Even then, the impact of greenhouse gases massively overshadows that. On top of that, there's no activity requiring exponentially more energy, or evidence that we may continue expanding energy demand for hundreds or years. In fact, if you look at per capita energy consumption vs GDP [2], you can clearly see a saturation of energy needs. Once the developing nations reach this, it seems demand growth is going to slow down. Nothing physical ever maintains an exponential growth for too long. [1] http://upload.wikimedia.org/wikipedia/commons/b/bb/The-NASA-Earth%27s-Energy-Budget-Poster-Radiant-Energy-System-satellite-infrared-radiation-fluxes.jpg http://upload.wikimedia.org/wikipedia/commons/b/bb/The-NASA-... [2] http://www.withouthotair.com/c30/figure242.png http://www.withouthotair.com/c30/figure242.png