Electronics Cooling Boosts Capabilities to Match Performance Upgrades

Article
Article
Article
November 02, 2020

Electronics Cooling Boosts Capabilities to Match Performance Upgrades

Published in Military & Aerospace Electronics
Written by John Keller

Here’s the good news: electronic and electro-optic subsystems for aerospace and defense applications progressively are becoming higher performance, smaller sized, and lighter weight. Now here’s the bad news: all those benefits have a major system tradeoff: a growing amount of waste heat.

It’s a fact of life that aerospace and defense systems designers can’t escape: the higher the performance and the smaller the size, the greater the amount of heat that designers must confront. It’s not as though electronic components can be designed economically that can tolerate huge amounts of heat. Instead, designers have to find ways to cool these ever-hotter electronic components, and they must do it affordably, and in small, lightweight packages.

Conduction Cooling

Perhaps the most widespread and best-known thermal management approach for rugged aerospace and defense applications is conduction cooling. These systems typically are sealed against airborne contaminants like dust and salt spray, and conduct heat outward from hot components inside the chassis to cold walls or ambient outside air. It’s relatively simple, reliable, and affordable, and has been a thermal management go-to for decades.

Conduction cooling often calls for wedge-lock devices along the edges of circuit cards to help transfer heat from the card, along rails, through the chassis, and eventually to the outside of the chassis where it is dissipated.

“Conduction cooling is by far the biggest cooling approach in terms of COTS hardware out there,” says Ivan Straznicky, chief technology officer of advanced packaging at the Curtiss-Wright Corp. Defense Solutions segment in Ashburn, Va. “Still, as power goes up, it becomes more difficult for conduction-cooled modules to handle cooling.”

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Cooling Techniques

Air-Flow-Through (AFT)  
Air-Flow-Through (AFT)

Ideal for high density, high power (150-200W) computing applications

Conduction Cooling  
Conduction Cooling

Ideal for lower density (50W) computing applications that require ruggedization

Convection Cooling  
Convection Cooling

Transfers heat from electronics into the ambient air using airflow

Liquid-Flow-Through Cooling  
Liquid-Flow-Through Cooling

LFT cooling uses a liquid-cooled system to cool cards from 200-1000W

Fluid-Flow-Through Cooling  
Fluid-Flow-Through Cooling

FFT cooling uses fixed channels (air-cooled or liquid-cooled) built into the chassis to cool the electronics

Thermal Management in Rugged Computer Systems

This white paper looks at the different cooling techniques available including conduction, convection, Air-Flow-Through (AFT), Liquid-Flow-Through (LFT), and Fluid-Flow-Through (FFT) and aims to provide clarity on how to choose the best solution.