Space requirements heat pump + ventilation

I have already used Google but never really found anything: How large does a boiler room for a brine/water hot water + central ventilation system have to be? Are there required distances here? Since space will probably be very tight: are there possibly also options to install the buffer storage in the area under a spiral staircase?

Are there required distances here?

Your basic supplier can help you with that, for example for electricity or water. Everyone has their own required minimum distances. And you are welcome to read up on this here: https://www.hausbau-forum.de/threads/mindestgroesse-für-ein-hausanschlussraum.31268/page-8#post-327494

Are there possibly also options to install the buffer tank in the area under a spiral staircase?

There are also brine-water heat pumps that already have the buffer tank integrated. This saves a lot of space.

Would any of you have an idea of your space requirements? It would already help me a lot for the rough planning.

Would any of you have an idea of your space requirements?

Certainly …!

Buffer tanks are usually omitted.