> 25% for cryogenic Also from Wikipedia, the efficiency if 25% if you let the heat of liquefaction and the "cold" of vaporization go to waste, but it can be im

> 25% for cryogenic Also from Wikipedia, the efficiency if 25% if you let the heat of liquefaction and the "cold" of vaporization go to waste, but it can be improved to 70% if you store that heat and re-inject it in the cycle.