Functioning / Efficiency of decentralized ventilation system

Hello!

We have been dealing with the question of central or decentralized for our new building for quite a while now. You read a lot. But I have not found anything yet regarding the actual functionality.

We are considering the decentralized devices from Meltem because they keep supply and exhaust air separate and ventilate continuously in both directions, so they do not oscillate. According to Meltem, one device is suitable for 30 m2.

If I have the device mounted in a corner under the ceiling, it is hard for me to believe (or maybe just technically understand) that it really causes an air exchange in the opposite corner possibly 6 m away. I can imagine that there is good exchange around the device in a radius of 1-2 m. But that far? There is also no negative pressure with incoming air because each device in each room operates independently.

Not to mention the fact that warm air rises immediately in summer and thus does not reach body height ...

Can someone explain this to me physically.

Thank you.

hausbauerin1

We have the Lunos E2 with heat recovery. With central ventilation units, you usually have a significantly higher throughput when it comes to air exchange. I can't explain this to you "physically," I haven't studied it. With the decentralized system, we achieve a certain basic demand for air exchange, which means no mold, no drafts, and no fan noise or airflow noise that is disturbing. If you want to "feel fresh air," you must not use heat recovery, or a system that never reverses direction. Then it draws in nice icy air in winter. With heat recovery, it is cool but not frostily cold. So far, I have not been able to detect any condensation problems on the wall/floor under the device. Maintenance is significantly cheaper with the decentralized solution because it is easy to access. That was my most important aspect. Furthermore, it can be significantly cheaper than a central ventilation system.

In a decentralized system, normally one fan exhausts and the other intakes. This is intended to create airflow throughout the entire floor, as indicated in the ventilation plan. And when you close the doors and feel with your hand at the bottom of the door, it actually works.

Decentralized solutions are suitable for the renovation of existing buildings and for new buildings, IMHO only if you want to regulate/control the ventilation of individual rooms (based on measured humidity or measured CO2 content). In all other cases, I would plan a central solution.

Thank you! Yes, if it works like that (Pendellüftung) I can imagine it too. But with Meltem, every device runs independently in each room, so air goes in and out at the same device simultaneously. I don’t know if there is still this exchange because it happens in each room. We want the ones from Meltem because supply and exhaust air run separately, which is usually not the case.