All too often, the overall performance of an electronic design isn’t limited by technology constraints, but rather ultimately boils down to a problem of heat dissipation. With the exception of superconductors, the operation of all electrical and electronic equipment results in some power loss, which is inevitably dissipated as heat.
Accepting this fact, equipment designers need to consider how that heat will affect the performance of their design and how to remove it from their system. In doing so, they can ensure that their design continues to operate correctly, with no damaging effects on individual component parts. As systems grow more complex, with rapidly increasing densities, the thermal management of your system becomes a major design consideration.
In many instances, heat can be conducted away from critical components, through the circuit board and case, and dissipated to the surrounding air. For larger systems, especially computers, servers and similar rack-mount equipment, where the combination of conduction and natural convection cooling isn’t sufficient, fans are often needed to provide forced-air cooling.
Once a designer reaches this conclusion, the next question is, “What sort of fan do I need?” followed by “What size does the fan need to be and what other criteria are important in specifying the right fan for my application?” As with most things in life, and particularly in engineering, there’s a process to go through to arrive at answers to these questions.