Experiences with brine heat pump

Yes, that is great! We accomplished it at the acquaintance’s place in one day. Large property and own excavator operator.
If you have such a chance, you have to take it!

Costs of trench collector under €2,500; funding €4,500. Compared to the air-water heat pump, money saved, plus lower ongoing heating costs, the passive cooling alone is worth its weight in gold, no annoying outdoor unit... Annual performance factor >5.5...

Simple calculation, since the trench collector was built by myself... I know. But including planning, it was less than 3 days.

Yes, that's cool, in this context I just remembered something I omitted: if you spend €12,000 on e.g. an air-water heat pump from Nibe, it actually pays off quite quickly. I have a significantly cheaper air-water heat pump for which, in comparison, the brine-water heat pump is not worthwhile.

We are planning a KfW 40 plus single-family house in NRW with a ground-source heat pump, a ventilation system, as well as a photovoltaic system with 6.3 KWp and a storage with 6.4 kWh. Basic data: 200 m2 living space, 50 m2 usable space (garage / basement / both heated), 4 persons, including 2 small children.

The heat pump manufacturer informed me that I only need a cooling capacity of 4.6 kW for this. He believes that a heating capacity of 6 kW is completely sufficient. This of course worries me a lot, especially when I compare the drilling meters with yours. Only 99 m are planned for me. What do you think?

The offers for the drilling vary extremely strongly from about 5500 EUR to 12000 EUR. What should I pay attention to when comparing the drilling prices?

Which heat pump would you recommend to me?

Make a room-by-room heating load calculation, design the underfloor heating based on this with a low flow temperature (e.g., 30 degrees). In the result, you will also see the heating load for the entire house and can dimension the heat pump accordingly.

A drilling contractor calculates with 55 watts extraction power per drilling meter at 2400 operating hours per year.

Do a room-by-room heating load calculation, plan the underfloor heating based on this with a low flow temperature (e.g., 30 degrees). As a result, you will also see the heating load for the entire house and can accordingly size the heat pump.

There is nothing more to say about it.