Fan Speed Control Using Maximum Temperature Error for Noise Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing cooling systems for electronics generate significant acoustic noise due to fan operation, and reducing fan speed to mitigate this noise risks inadequate cooling and equipment damage, especially since current methods require overcompensation for worst-case conditions.

Innovation Solution

A fan speed control system that uses temperature detecting means at multiple locations within an enclosure to determine the maximum temperature error and adjust fan speed accordingly, minimizing noise while ensuring adequate cooling for thermally sensitive components, with features like temperature bands and filtering to stabilize fan operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If fan speed is reduced to reduce acoustic noise, then acoustic noise level decreases, but cooling effectiveness deteriorates and equipment may overheat

Engineering Contradiction:

Improveacoustic noiseVSAvoidequipment temperature

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The fan speed control system dynamically adjusts fan speed based on real-time temperature readings from multiple sensors located at different positions within the enclosure. The controller continuously monitors temperatures and modulates fan speed to maintain cooling effectiveness while minimizing acoustic noise, rather than operating at fixed high speed to accommodate worst-case conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs multiple temperature sensors positioned at specific locations throughout the enclosure to detect local temperature conditions. Each sensor monitors the thermal state of nearby components, enabling localized temperature-based control decisions that accurately reflect actual cooling needs rather than relying on conservative worst-case assumptions.

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If fan speed is controlled based on ambient temperature and electrical load, then power consumption decreases, but fan speed may be insufficient for worst-case cooling conditions

Engineering Contradiction:

Improvefan power consumptionVSAvoidcooling adequacy

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The control system uses real-time temperature feedback from multiple sensors positioned at critical locations within the enclosure to dynamically adjust fan speed. This feedback mechanism ensures that fan speed is always sufficient to maintain temperatures below threshold values, while avoiding unnecessary high-speed operation that would increase power consumption and acoustic noise.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If multiple temperature sensors are used to accurately detect thermal conditions, then cooling control precision improves, but system complexity increases

Engineering Contradiction:

Improvetemperature detection accuracyVSAvoidcontrol system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The enclosure is divided into multiple thermal zones, each monitored by dedicated temperature sensors positioned near specific components or component groups. This segmentation allows the control system to accurately detect local temperature conditions without requiring a single complex sensor system, and enables targeted cooling control for different thermal zones.

Inventive Principle:

Principle #1Segmentation

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

This approach reduces acoustic noise by adjusting fan speed based on actual thermal needs, avoiding overcompensation for worst-case conditions, thus maintaining effective cooling and minimizing equipment damage while reducing noise levels.

Implementation Method 1

a plurality of temperature detecting means, each having an associated setpoint temperature, disposed at a plurality of locations throughout the enclosure

Methodology Applied

Scientific EffectTemperature detection:

Implementation Method 2

larger forced-air thermal management systems to cool this equipment

Methodology Applied

Scientific EffectForced convection: Forced Convection

Implementation Method 3

cooling air flow velocities while ensuring that thermally critical areas do not overheat

Methodology Applied

Scientific EffectHeat transfer: Convection

Data Source

PatentUS7331532B2Acoustic noise reduction using fan speed control

Publication Date: 2008.02.19 CIENA CORP

AI summary

A method and apparatus is disclosed for acoustic noise reduction using fan speed control. The acoustic noise reduction using fan speed control includes a plurality of temperature detectors disposed at a plurality of locations within an electronics equipment enclosure, each detector having an associated setpoint temperature. An error value is determined for each temperature detector, the error consisting of the difference between the detected temperature and the associated setpoint temperature. The maximum error among all error values is then identified and the operating speed of a cooling fan in is set in response to this maximum error. Advantages include providing a fan speed directly related to electronics temperature which inherently accounts for higher ambient temperatures, enclosure altitude, electronics power consumption, and air filter clogging. The acoustic noise reduction using fan speed control is particularly useful for overcoming the need to overcompensate fan speed, thereby resulting in higher than necessary noise levels in order to accommodate worse-case conditions known in the art.