At Data Center Dynamics in Toronto we came to realize that there is still some confusion when it comes to passive versus active air flow. I hope this will help demystify the confusion.
At present Hammond offers two passive cabinet systems for your Data Center environment. These include the cabinet chimney and the hot-aisle containment system. Both offer high efficiency cooling through a passive HVAC system.
Hammond's passive chimney keeps air from mixing in the room and is vented into the plenum (space above ceiling tiles). Sometimes the plenum may contain individual ducts that route air from the cabinet chimney back into the HVAC system or the plenum would be open with a main duct drawing air into the HVAC unit.
The second system is our passive row cooling solution that essentially is two rows of cabinets with the rear end facing each other. The row includes a sealed top panel and door to prevent air mixing. At the end of the row there would be a large hot air return that would go to the HVAC unit.
In both cases our systems to not have any additional fans forcing the air into the HVAC, therefore our systems are passive and rely on the force generated from the HVAC unit.
If your data room was located in an old warehouse or manufacturing facility, your cabinet would have a NEMA rating and would include either filter fans or air conditioner. This setup would be known as an active system.
There are some pros and cons of each but one benefit of a passive solution is you would usually have a backup HVAC unit where you may have an outage should an active solution shut down.
For more information on our containment systems stay tuned until next month when we hope to present a new case study.