Internal heat pump in the basement not possible due to groundwater?

I find the suggestions of my predecessors on the topic of explosives good and would also work toward a compromise with the GU. However, this requires, as mentioned, that you push a bit to limit the risk to an acceptable level.

Regarding the design water level, I can imagine that very cohesive soil was found during the preliminary investigation, so that surface water remains for a long time or there is groundwater within layers. The groundwater table alone does not determine the design water level. I believe that values from the hundred-year peak water level/precipitation, etc. are included. Then an additional 30 cm safety margin is added = design water level. At least, that is how it is in our soil report. Whether there is a standardized calculation formula is beyond my knowledge.

We have groundwater at -2.5 m, actually only fluctuating by 50 cm, but the design water level was indicated as 0 in the report. In other words, the ground surface. That is approximately where the water stood in 1999 during the worst Danube flood of the last 100 years.

Parcus’s objection is justified, but there are many conditions that can lead to this type of specification being chosen. It can be examined whether there is an alternative and whether the GU can (technically) follow.

Was your house plan available to the geologist at the time the soil report was created? Your quoted excerpts from the report appear very generally formulated and less specific to your construction.

An indoor heat pump is in no way inferior to an outdoor one in terms of efficiency. No idea where such old wives' tales come from.

The shafts are around the corner and a few meters apart... they don't affect each other at all.

@ here are the facts: With R290, good heat pumps today can achieve supply temperatures up to 75°C and still operate at -15 to -20 °C, so no heating element is needed anymore. GWP number 3. The indoor or rather split heat pump plays to its advantage in cooling load using R32 as refrigerant. GWP number 675. (R410a is terribly bad with a GWP of 2088.) However, politics has now understood this as well and already implemented it in BEG 2023. Then try telling the intake air that it is not allowed to turn a corner. Facts can clearly be measured here via airflow and temperature :) Therefore, you can, for example, forget oscillating fans,... the devices simply stabilize at an average temperature.

To be honest, I don't know what to say about that? Weren't you also the one who already mixed up some terms in another thread?

monovalent has nothing to do with monoblock and [innen aufgestellt] does not mean Split.

Regarding air flow, how large is the distance between the intake and outlet at an [außen aufgestellte] air-to-water heat pump?

@

The terms are clearly defined. Monoblock = cold and warm side in one block

Monovalent = only one heat generator Whereas these heat pumps can be operated with R290.

Split = at least two heat generators Whereas these cannot be operated with R290.

Otherwise, the Duden can also help you with "mono" in the meaning of only, alone, single;

The indoor or rather split heat pump plays its advantage…

If that is so clear, please explain this to me?

and this:

The outdoor heat pump is much more efficient because of the monovalent operation

What does being installed outside have to do with monovalent?