Hi, I used to be a fan of the technology but it’s not worth it. It is technically too complex.
Alternative: If you have space in the garden, use a Ringraben collector. It provides ideal supply temperatures for a water-to-water heat pump almost all year round. With your own work, it is even cheaper than an air-to-water heat pump.
I find cooling with an underfloor heating system problematic. It’s only a few degrees and you have the dew point problem.
Better to invest the saved money in a larger photovoltaic system and an air conditioning unit.