Reducing product noise by managing heat

Increasing heat loads and component densities in IT equipment make it difficult to meet noise emission targets. Integrated thermal and acoustic design are all but required. Recent experiences with two full-rack servers highlight this fact. Both units were intended to meet the requirements of GR63-CORE NEBS (tm) Requirements: Physical Protection, §4.6 Acoustic Noise. One came close to meeting the requirements, but the less powerful unit was considerably louder. Investigation revealed that an ineffective thermal design all but guaranteed excessive noise. The paper will examine the basic design parameters of the two units, explore the acoustic ramifications of general thermal design, and reveal some simple noise control guidance for design teams.