When I was thinking about building my own ASHP for hot water heating,
I wanted to pickup heat outdoors in the summer, and indoors (basement) in the winter.
Instead of a valve system, I had the idea of using dual compressors.
(Since I would be needing another fan and HX unit anyways).
Maybe the idea of dual compressors with indoor and outdoor HXs, could be adapted for a fridge hack??