What does that mean “refrigeration tech […] energy hungry”? The technical appilcation of the Carnot-Cycle is as close to maximum mathematical efficiency as we can get. Sure, it’s far from 100% efficient but we’re actively going against entropy here. In the end it all comes down to thermal isolation and losses. Even cheap fridges from the past 20 years take like 100 Watts once they’ve reached their target temperature. That’s only a bit more than a laptop and a bit less than a desktop computer on idle. AC-Units take a lot more but we already have a 100% efficency solution, it called “not bitching about the heat”.