Increasing Electronic Enclosures Airflow Pumping Power Efficiency by Reducing Airflow Pressure Losses Through Modification of the Rear Tailstock and PCI Airflow Domains
Publication Date: 2012-Oct-11
The IP.com Prior Art Database
AbstractDisclosed is a method of reducing an electronic enclosure's box pressure impedance/airflow losses by creation of additional perforation out of the enclosure's top side while maintaining the component density within the electronic enclosure and preserving room for connectors and adapters at the rear.
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Data centers and system developers are under pressure to cut cost and have known that system box airflow impedance - the amount of air pressure required to push a definitive amount of volumetric airflow through an electronic enclosure - determines how much work that the system air movers (fans and blowers) must provide. The latest generation of smaller sized counter rotational fans (<120mm) are now capable of 2x -3x performance of that of just a generation ago but at a significant cost in electrical power. Fans in these form factors were once only 30-40W and are now breaking the century mark at maximum speeds and workloads. The culprits of this airflow demand explosion are two fold; the first in the amount of power consumption which electrical components now need to dissipate and cool; and secondly, the density of which these electrical components are packed into an electronic enclosure. Along with higher power components comes the requirement of enhanced cooling solutions and increase airflow. With limited innovations in heatsinks and spatial restraints, one of the last options is to increase the airflow. While the front of most electronic enclosures have a fair amount of perforated areas available for airflow intake into the enclosure, the rear width nearly 100% utilized becoming densely populated with PCI tailstocks, power supplies, and essential interconnect cables with bulky over-molds. This limits the area of non-obstructed sheet metal which can be perforated and used as system exhaust.
Besides the standard method of increasing system airflow accomplished by increasing fan speeds or selecting a higher performance air mover carries significant penalties including, but not limited to, higher acoustics, higher power consumption, higher initial and operating cost, lower life expectancy, etc. In addition to the obvious, the problem imposed by these penalties, simply increasing fan speeds does not correlate to an equivalent amount of airflow delivered as the pressure impedance is often a square of the volumetric airflow rate. To effectively increase the airflow allowed out of the electronic enclosure for a fixed pressure, either the aperture size of the perforated area must be increased or the area size which is perforated must increase. Due to EMC conflicts with larger aperture sizes, increasing the area available for perforation is just about the last of the mechanical design options available. Although there can be perforations squeezed in between PCI adapter tailstocks and in the tailstocks themselves, the restriction of area for exhaust airflow will be a dominate contributor to the overall system impedance. Reduction of air mover speed by just 100's rpm can have significant power savings.
To effectively counter the cumulative increases in airflow resistances within an electronic enclosure and enable the reduction of fan speeds/power and/or acoustics, additional exhaust areas had to be...