Published in Electronic Design
As rugged computer systems designed for military programs grow more powerful and more complex, keeping these systems cool under harsh conditions becomes more challenging. Customers and suppliers have a variety of cooling techniques they can and do use, including conduction, convection, air flow-through (AFT), liquid flow-through (LFT), and fluid flow-through (FFT).
For many years, conduction cooling has played a major role in the thermal management of rugged systems, but there are limits to how much heat can be dissipated by conduction cooling alone. Most traditional conduction-cooling methods are unable to disperse the heat generated by today’s hotter cards. Where once it was commonplace to have 50-W cards, 120- to 200-W cards are becoming more common.
Conduction Cooling
Conduction cooling is the transfer of heat through solid materials. A common example might be the conduction-cooled chassis-mounted onto a cold plate (Fig. 1). The heat generated inside the chassis by the electronics flows into the chassis aluminum sidewalls and down into the cold plate.
1. Conduction cooling transfers heat from the computer to a cold plate.
At the board level, a similar mechanism for conduction cooling transfers heat from the components through a conduction frame to the card edge and beyond to the “cold wall” of the chassis.