I recently had a discussion about ACs and how they heat up cities.

Then I found an article about theoretical increase of efficiency of acs by using the heat pulled from a room to run a thermoelectric device and getting some of the energy back that was used in the ac.

I‘ve had this downstream thought many times already: since hot air is basically just energy stored. Could we theoretically pull (all?) the energy from the air (depending on desired temp) to cool it and casually fuel our society’s energy needs?

  • I understand. Thanks for explaining.

    What still eludes me is if I have 35c outside and want 25c inside, those 10c times cubic meters go outside in the form of 50 or 60c hot air. And I think thats why people like me think it is possible to get those 15-25c difference back in the form of electricity (or at least not spend them so that the excess heat is not pumped outside).

    • Those 15-25c difference exist to drive the heat energy from the radiator into the air. If one would want to not waste as much energy for this, the actual solution would be to use a bigger radiator that can dissipate the same heat energy per h while being lower temperature. That would need way less additional material and be way more efficient than building another harvesting machine.