How to give a rack a vertical exhaust chimney, or build a passive or active ducted chimney that still allows per-server loads, in a non-raised room.
This video shows ways to model a rack exhausting through a chimney in a non-raised floor room.
What the video shows
- Simple chimney: set the rack to front to top, then turn on the vertical exhaust duct in the geometry tab and set its height. This assumes all of the rack’s heat leaves through the chimney, and only an average load per rack can be set.
- Ducted chimney: set the rack back to front to rear, shorten its depth, and add a duct on the back of the rack. Connect the duct to the rack, then add a sub-duct as the chimney and finish it with a diffuser. This is a passive chimney.
- With this build, the individual rack tool still works, so servers, gaps and loads can be set at specific heights.
- Active chimney: remove the diffuser and place a power distribution unit (PDU) object on top of the duct, used here as a fan. The presenter names a typical fan load of about 500 watts and airflow of around 2,500 cubic feet per minute (CFM) or more as examples.
- Add a cooling unit, save, run the job, and check status. The results show path lines rising through the chimney. Pressing the E key makes a surface transparent.
- Group the assembly, save it to the user library, and export it to share with colleagues.
Tips
- The active chimney flow rate must exceed the total airflow of the equipment in the rack, unless a gap in the rack relieves the pressure. Otherwise pressure problems build up behind the rack.
- The presenter notes that chimneys like this are usually used with a ducted return or a ceiling plenum, not in a room without one.