Which geothermal energy should be used?

The first company works with refrigerant and the second with water.

I don't quite understand that yet. Both offers provide direct evaporation heat pumps with surface collectors. How does one of the two do it with water? Or do you mean the offer from Beglau, because there is talk of condensation in the storage tank? How does the underfloor heating get warm then?
I must admit I haven’t dealt much with direct evaporation heat pumps so far.
Content-wise, both offers are definitely hard to compare anyway, as very different services are offered, but you are probably aware of that too. Beglau says nothing at all about the length of the necessary surface collectors (but apparently criticizes the length of the competitor’s, if I understood your last post correctly) or offers installation at all.

Yes, I mean the capacitors in the storage, furthermore I am surprised by the difference in the buffer tanks, actually the small one should be sufficient enough

We have a heat pump as a DV with collector surfaces in use (however, none of the ones presented here). When the heating system is properly set up, it runs without problems. However, sufficient refrigerant must be filled, and the pressures must be correct. Since this was not always the case with us, there were significant uplifts and settlements in the garden during the first year. We have the same heating system in use again in the residential area, and there have been no such problems so far. There, the collector surface was also designed somewhat more generously, which apparently also benefits consumption. So definitely do not save on the surface area. We have approximately 140m² of collector surface for 125m² of living space.

You should definitely be aware that the surface must not be built over, no plants with root depths >80cm may be planted, and in spring the area lags behind the rest of nature by at least 2 weeks. That sounds uncomplicated at first..."we just want to make lawn there anyway," however, a garden also changes over time, and you will then be correspondingly limited.

Furthermore, we use a stratified storage tank. It works without problems during heating periods. In summer, however, you have to be very careful that the set heating times also match the usage, as I operate very low flow temperatures. Definitely ask how the water is heated.

Also ask about maintenance costs and intervals.

I just looked on the Libind site and on the Beglau site.

Libind The refrigerant flows through the collectors and also through the underfloor heating. What I did not find out is whether these are two different circuits or just one circuit. The domestic hot water is apparently produced using a separate domestic hot water pump.

The Beglau heat pump works like ours The refrigerant goes through the collectors. The storage tank of the heating is heated via the DV. The fresh water line runs through the storage tank and is heated as it flows through. Here you probably have exactly the same problem in summer as we do. The 600 liters must be heated so that the fresh water reaches the temperature as it flows through. For this you never have a problem with legionella because there is no fresh water storage tank.

Type Libind and the product name on YouTube, there's a video.

I also think that the water reservoir is set a bit high, we have 130m2 so I think 150m2 should be quite sufficient.

We know about the garden, we only want lawn there as it is at the end of the property.

I was now concerned about which offer appears better there.