Detached house solid construction - How to air condition, heat pump and underfloor heating?

I suspect you are aiming here for a correspondingly good insulation + shading so that in summer the room temperature does not follow the outdoor temperatures but rises significantly slower.

This works well as long as the temperatures drop significantly at night, so that cool air can enter the house again and the exterior walls can cool down.
And of course, as long as the windows/doors are closed and no sun comes in... once I have the heat inside, I can only get it out without active cooling if the temperatures drop significantly at night...

But as soon as I have real midsummer where the temperature does not fall below 22° at night, I slowly get a problem without getting cool air "somewhere"... whether through active cooling by an air conditioner or through a pipe in the ground where it is a few degrees cooler...

The topic of cooling in summer is currently occupying me somewhat... I simply do not sleep well at high temperatures and I am the type of person who sweats quickly and also has no problem walking around in a T-shirt at 15°...

Good insulation and external shading is therefore already set, but I wonder if it makes sense to invest in additional air conditioning units...

A controlled residential ventilation system is also planned... Now there are several options to make the summer climate more pleasant:
- Controlled residential ventilation with the possibility to regulate humidity, because dry air is more pleasant at high temperatures than additionally high humidity
- Controlled residential ventilation with geothermal heat exchanger - provides a few degrees cooler air without active cooling; the question is how much it can lower the room temperature... possibly 1-2°... so not suitable for REALLY cool rooms
- Controlled residential ventilation with additional cooling unit similar to an air conditioner... no experience with how effective the cooling is here
- Air conditioner for certain rooms, e.g. bedrooms so you can properly cool here in the evening.. downside is that it is only for 1 room and consumes relatively a lot of energy and is not particularly appealing visually...

Yes, as far as the issue goes. I have already looked into several directions. It probably only gets really cool with a proper air conditioning system. Ultimately, the energy consumption there is probably not that bad, because with the measures already mentioned, such as proper ventilation, shading, insulation, etc., it will not be many days throughout the year when support is necessary.

Is there, for example, a possibility to temporarily use a [Kontrollierte-Wohnraumlüftung] as a central air conditioning system? The ducts lead to every room – the airflow just needs to be significantly increased, and instead of the heat exchanger, the inverter of the air conditioning system would blow into the pipes. I would like to avoid a decentralized multi-split system as much as possible, and installing additional ventilation ducts alongside the [Kontrollierte-Wohnraumlüftung] is also not really optimal...

Best regards Daniel