Active Noise Control Rack Enclosures for Server Fan Noise

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Solution Overview

Problem

Computer server rooms face excessive noise from cooling fans, which disrupts productivity due to the inability of existing sound-absorbing materials to completely eliminate ambient noise, and are often impractical due to cost and fire safety concerns.

Innovation Solution

Implementing a system with transducers and active noise control units that emit acoustic waves 180 degrees out of phase with fan noise, using microphones to analyze and match the frequency and intensity of fan noise, effectively canceling it.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If sound absorbing materials like acoustical foams are used to reduce fan noise, then ambient noise is reduced, but the noise is not completely eliminated and the cost increases along with fire safety concerns

Engineering Contradiction:

Improveambient noiseVSAvoidcost and fire safety

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention converts the harmful fan noise into a beneficial signal by using microphones to detect the noise and active noise control units to generate anti-phase acoustic waves. This transforms the problem of noise reduction into a solution where the noise itself becomes the input for generating the canceling sound, effectively eliminating the need for expensive fire hazard materials.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention replaces the passive mechanical sound absorption materials (acoustical foams) with an active electronic system consisting of microphones, active noise control units, and speakers. This substitution allows for more effective noise cancellation while avoiding the fire safety issues and high costs associated with traditional acoustic materials.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If multiple cooling fans are installed in system racks to cool computers and servers, then cooling effectiveness is improved, but excessive ambient noise is generated that reduces personnel productivity

Engineering Contradiction:

Improvecooling effectivenessVSAvoidpersonnel productivity

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The invention introduces an intermediary active noise control system between the cooling fans and the personnel. The microphones capture fan noise, the active noise control units process the signals, and the speakers generate canceling sounds, creating a mediator system that protects personnel from noise while allowing fans to operate at full cooling capacity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system applies preliminary anti-action by generating acoustic waves that are 180 degrees out of phase with the fan noise before the noise reaches the personnel. This preemptive cancellation approach allows the cooling fans to operate at full speed without compromising personnel productivity, as the harmful noise is neutralized in advance.

Inventive Principle:

Principle #9Preliminary anti-action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Significantly reduces or eliminates cooling fan noise, improving productivity and reducing noise-related distractions in server rooms, while being more cost-effective and practical than traditional sound-absorbing materials.

Implementation Method 1

at least one of the one or more transducers emit transducer acoustic waves to reduce or essentially to eliminate the fan noise

Methodology Applied

Scientific EffectAcoustic wave generation: Sound

Implementation Method 2

emit acoustic waves 180 degrees out of phase with fan noise, using microphones to analyze and match the frequency and intensity of fan noise, effectively canceling it

Methodology Applied

Scientific EffectDestructive interference: Interference

Data Source

PatentUS7894613B1Active noise control rack enclosures

Publication Date: 2011.02.22 ORACLE AMERICAN INC

AI summary

Provided is an apparatus and method to control fan noise in a computer server room. An exemplary apparatus includes one or more transducers coupled to one or more walls of a plurality of system racks and one or more active noise control units, wherein the one or more active noise control units send control signals to the one or more transducers to emit a transducer acoustic wave. It also includes a microphone installed near a location in the computer server room where cooling fan noise needs to be controlled, wherein the microphone collects fan noise signals emitted from running fans on the plurality of system racks in the computer server room and sends the collected fan noise signals to the one or more active noise control units to allow the frequency and intensity of the transducer acoustic wave to be substantially equal to a frequency and an intensity of the fan noise and at about 180 degrees out of phase with the fan noise to reduce or to eliminate the fan noise.