I used to smoke cigars in my home-office, and the ventilation was pretty much set up for that. My duct fan was connected to an active carbon filter in the ceiling, to make sure the smoke would not be noticeable outside and leak back in when the bedroom windows were open in the summer months. That happened once and the girl friend did not approve.
Anyway; after I got the homelab properly set up, smoking cigars in the office just didn't feel right... All that smoke drawn into the servers, heat-sinks, filters and so on. Never mind the lungs, think of the servers! So it was time to rebuild the exhaust ventilation system to better suit my new needs.
So this is how it used to look, that needed to come down.
I removed the active carbon filter and the noise trap. I initially installed the noise trap because the distance between the intake and the fan was very short, and there was no bends. This allowed high-pitch noise from the fan itself to be quite audible. I figured I wouldn't need it anymore with the longer duct runs.
I wanted the new exhaust system to be dual purpose; remove hot air from the homelab and solder fumes from the electronics lab. So I got a T-branch and spiral tubes which I cut into suitable lengths.
Next I cut and pre-bent suspension bands.
And the first section is up! I used two suspension bands on each side of the T-branch, and connected it to the fan with flexible duct. This allowed me to mount the spiral tubes a bit closer to the ceiling as the flexible duct could be bent upwards.
I mounted a 90 degree bend and intake above my electronics lab, pretty much right over where I usually solder.
On the homelab side I first mounted a 90 degree bent towards the wall, then another to go down, and finished it with an intake there as well.
The idea here was the hot air from the servers could rise up behind the rack and into the exhaust.
So this is how it turned out. I'm not sure how efficient the intake over the homelab is... It might be that the hot air pushed towards the wall behind the rack will spread in all direction and not really "rise" up like I imagined it would. Furthermore I don't have any convenient way of adjusting the airflow on the two intakes. I can rotate the disk on the intake, but it's a bit annoying, might have to work out something better eventually.