[edaemon]

Regular refrigerators use the same principle, albeit with a mechanism much simpler than a heat pump. They have holes between the freezer and refrigerator compartments and use a fan to push cold air from the freezer to the refrigerator. A heat pump would make that exchange much more efficient.

[JoeAltmaier]

I doubt that heat pumps could be more efficient than direct exchange of cold air?

[edaemon]

There are periods where you don't want the cold air to move into the refrigerator. Direct exchange allows the cold air to move around at all times -- regular refrigerators just turn a fan on and off, but some heat is always exchanged through the holes. A heat pump would just make the exchange more controllable.

[ndnxhs]

I have a fridge that works with just holes. You can either have the fridge or the freezer at the right temp but not both.