In search of a quiet fan

It is commonly assumed in the design of fan-cooled systems that, after the thermal design is complete, a low-noise result is achieved by selecting a quiet fan. This assumption proceeds from the mistaken belief that noise emission is a fixed property of the fan. Frustration and disillusionment result when, too late in a product's development, even a supposedly quiet fan turns out to be noisy. In reality a fan's noise emission is largely determined by seemingly unrelated decisions made early in the design process, whose practical consequences can overwhelm an otherwise quiet fan's relative advantages. The key to success is an integrated approach that requires thinking differently and much earlier about fan noise emission: a quiet system rather than a quiet fan. In exchange for the extra effort, cooling-system designers are empowered to set themselves up for success.