Our readers know of Tony Koryban. He always has an interesting take or two on thermal engineering and on the topic of fans in thermal management he’s not silent. Tony received this question in his mailbag on fan use and it’s an age old question:
Which is better, mounting a fan at the inlet of my chassis so it pushes the air in, or at the outlet, so it draws the air out?
from Quandary, Minnesota
What’s your guess? Or what’s your standard practice? Let’s give Tony a chance to answer by clicking to his answer at this link here: Tony Koryban Mailbag Archives
…. and don’t forget, you can see Tony in person, at Cooling Zone 2010
Posted in Fan
Tagged air flow, Fan
Fans, or other air movers, are a critical part of any system level thermal management solution. There are cases where a fan is not preferred, such as in medical equipment (see our earlier post on that topic here), some military applications and in some consumer applications. And, fans do present the unwanted chance of mechanical failure being introduced into a system.
In a white paper written by ebmpapst, they note that:
Fans create a flow of air, which they can then force through equipment that needs cooling. The necessary output is determined from the flow rate and the required static pressure. If the airflow through the equipment is restricted to any great extent by built-in components or bends and junctions, then this will lead to a loss of pressure; the fan will try to compensate for this by an increase in the static pressure, though the fan will have to work harder than in free air operation. The characteristic curve of the fan gives precise information about the flow rate at specific static pressures.
Understanding these curves is critical and ebmpapst has a good, introductory white paper to help you understand them. You can get your copy of their quick and useful read by clicking: Fan Curves and Optimum Operating Points.
ATS, Inc. is announcing a new “on-demand” webinar from our thermal engineering team, “Methodologies for Fan Characterization”. This webinar is ready for download and listening 24 hours day from the ATS web site.
Topics covered include:
- What are the fan types and points of application?
- Understanding how fans operate and the effect of bypass flow on their operation
- Fan selection
- Fan assemblies and their implementation
- Use of fan laws for sizing
- Managing acoustic noise
- Fan characterization
To take part in this webinar, just click to our site to reach the webinar at: Methodologies for Fan Characterization
While heat sinks do a terrific job of moving heat from a hot chip, cool air (or another moving liquid) is very helpful to move that heat off the chip and out of the system. Individual fans are one way to approach this problem. Another is by use of a fan tray.
A fan tray is an array of fans put together in a removable tray of some kind. There are various types and configurations based on whether you need to move air for a computer server, telecomm central office equipment or medical equipment. Fan trays are very helpful in developing a system level thermal management solution.
While on the surface of it, a fan tray appears to be no more than a number of fans placed in a frame there is actually quite a bit more there. From the kinds of fans, to the circuitry used to control them, fan trays are really an air moving system that, when engineered right, can bring real benefit.
ATS’s Thermal white paper will give you a basic sense for what’s involved, so click to it at our site now, “How to use fan trays in electronic enclosures; an ATS Thermal Labs “how to” white paper.