Die offizielle Bezeichnung für das Küchengerät lautet Mikrowellen-Ofen.

Probably because it’s a microwave oven, not a electromagnetic wave of certain spectrum.

The fridge would actually have to work harder though, to maintain a larger temperature difference between its hot and cold sides. So it’ll likely use more energy than the way fridges normally work.

I think their idea is to still use the chill air from the room for cooling the heat exchanger of the fridge, but transporting the then hotter air outside of the house (like a proper kitchen hood does) instead of keeping it in the kitchen.

Austrian Kaiserschmarrn

You have to use the proper translation, otherwise Americans won’t understand you: