Re: Underground
"If it was possible to make the exhaust part of an air conditioner even hotter, that could allow better heat transfer outside, even in the hot conditions described in the article. What stands in the way? Metallurgical limits? Properties of the refrigerants?"
Thermodynamics. The efficiency of an ideal air conditioner is Tin / (Tout-Tin) So the bigger the difference between the internal and external exhaust temperatures the lower the efficiency. Real air conditioners must be less efficient and also generate some heat of their own from the motor etc which subtracts further from the efficiency. If the temperature difference gets too high they end up with zero efficiency, basically just expensively pumping out the heat that they are making.
Biting the hand that feeds IT
