Electronic Rack Cooling via Internal Air Distribution Ramps

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Solution Overview

Problem

The cooling of electronic equipment in aircraft is limited by the constraints of aeronautical standards like Arinc 600, which restrict the diameter and number of ventilation holes due to electromagnetic shielding requirements, leading to inadequate natural convection cooling and increased temperatures during loss of forced ventilation, posing safety and compactness challenges.

Innovation Solution

The implementation of internal air distribution ramps supplied with pressurized air, connected to a forced air circulation channel, which enhance natural convection cooling by creating additional airflow paths between modules and fins, allowing for more efficient heat dissipation without violating pressure drop constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the diameter and number of ventilation holes are reduced to meet electromagnetic shielding requirements, then electromagnetic shielding effectiveness is improved, but natural convection cooling capability deteriorates

Engineering Contradiction:
Improveelectromagnetic shielding effectivenessVSAvoidcooling capability
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The ventilation system is segmented into multiple small holes distributed across the case surface, rather than using fewer large holes. This segmentation maintains electromagnetic shielding by keeping individual hole diameters small while collectively providing sufficient ventilation area for natural convection cooling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from relying solely on horizontal ventilation holes to utilizing vertical airflow paths through the case thickness. By creating pressure differential and enabling air to flow through the depth of the case, additional cooling dimension is added without increasing the number or size of surface holes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Temperature

If additional air intake orifices are added to improve natural convection cooling, then cooling capability is improved, but pressure drop constraints are violated

Engineering Contradiction:
Improvecooling capabilityVSAvoidpressure drop
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

A flexible diaphragm is introduced as an intermediary element that transmits pressure differential from the forced ventilation system to drive natural convection airflow through the ventilation holes. This mediator enables the forced air flow to indirectly enhance natural convection without directly adding intake orifices that would violate pressure drop constraints.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces the need for additional mechanical intake orifices by using the existing forced ventilation pressure differential, transmitted through a flexible diaphragm, to drive natural convection airflow. This substitution achieves enhanced cooling without adding mechanical openings that would increase pressure drop.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If forced ventilation is lost, then energy consumption is reduced, but temperature control capability deteriorates

Engineering Contradiction:
Improveenergy consumptionVSAvoidtemperature control
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The case is pre-designed with ventilation holes and natural convection pathways that are ready to function immediately when forced ventilation fails. The geometric configuration of holes and internal surfaces is prepared in advance to facilitate passive cooling airflow without requiring any additional activation or components.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The natural convection system enables the case to cool itself passively using ambient temperature differences and buoyancy-driven airflow. When forced ventilation is lost, the system automatically transitions to self-service cooling mode, eliminating the need for external energy input while maintaining temperature control capability.

Inventive Principle:
Principle #25Self-service

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 solution effectively limits temperature increases during loss of forced ventilation, enabling increased compactness and integration density of electronic equipment by augmenting natural convection cooling while maintaining compliance with electromagnetic shielding and pressure drop standards.

Implementation Method 1

internal air distribution ramps supplied with pressurized air via a distribution box connected to a forced air circulation channel

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

internal air distribution ramps supplied with pressurized air

Methodology Applied
Scientific EffectPressure Gradient: Pressure Gradient

Implementation Method 3

ventilation orifices by natural convection on its lower and upper walls

Methodology Applied
Scientific EffectNatural Convection: Free Convection

Data Source

PatentEP2057874B1Electronic rack having natural convection and circulation of forced air for cooling it
Publication Date: 2011.09.28 THALES SA
  • EP2057874B1 patent drawingFigure 1~2
  • EP2057874B1 patent drawingFigure 3~4

AI summary

This rack (1) houses rackable modules (2, 3) of electronic equipment and has a natural convection cooling system thanks to ventilation holes (20, 21) made in its lower (10) and upper (11) walls and a forced-air cooling system thanks to internal air delivery rails (30) fed with pressurized air by means of a distribution box (31) connected to a forced-air circulation line (37). By using internal delivery rails for the forced air it is possible for the circulation of drawn air to be only a slight obstacle to the air circulation obtained by natural convection. Compared with standard configurations, this makes it possible to lower the operating temperature reached by the equipment in the event of a loss of forced ventilation.