Sandia-Cooler - How it works
Category : Articles
Published by Marc Büchel on 15.07.11
Jeff Kopolow who is researcher at the american Sandia National Laboratories has developed a mechanism is capable of cooling recent processors in a much more efficient way then conventional aircoolers or even watercoolers. Therefore he discovered an entirely new approach whereas the only thing he needs is a rotating cooling block with. 
A technology which has offered room for improvement since a long time concerns the one which is behind conventional air coolers. The traditional design makes use of a cooing block and an appropriately sized fan. The efficiency this solution offers is about three percent and therefore quite poor. The bottleneck in this system is the layer of "dead air" which is between the fins and has a very high thermal resistance. If there now was a possibility to decrease the thermal resistance to a minimum this would sovle this issue permanently.
Page 1 - Introduction
Page 2 - Basic Thoughts
Page 3 - How does it work?
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Basic toughts
The traditional approach to increase the performance of an aircooler was either to increase the size of the cooling block or the equip the cooler with a fan which has a higher volumetric throughput. Therfore the scalability of this approach is limited. In a data center for example it simply isn't possible to increase the size of a cooling block by factor 20. Furthermore both, size and power consumption of a cooler, do have a direct influence on cost and operating noise. Last but not least the conventional "Fan-Plus-Fin-Heatsink" approach is a very mature technology and leaves almost no more room for improvement.The most important bottleneck concerns the thermal resistance of the layer of "dead air" between all the different fins. At this point heat is exclusively being exchanged by diffusion. The result is an inevitable, thermal bottleneck whereas the reason is the thermal resistance of air. Until today nobody has found a practical solution which eliminates the issue of this isolating layer of "dead air". Another problem concerns the inevitable fouling of the heat exchanger surface over time by particulate matter and other contaminants air consists of. In this case the cooling block becomes polluted, the air can't pass the fins appropriately and the efficiency of the entire cooler decreases. The third problem concerns inadequate airflow from the fan which causes a lot of noise.
The "Air Bearing Heat Exchanger" as Jeff Kopolow from the Sandia National Laboratories calls it, addresses all the three issues mentioned above simultaneously. Therefore the air layer between the fans is being minimized by a several-fold, the cooler becomes immune to pollution and the noise level can be reduced drastically.
Like a conventional air cooler the "Air Bearing Heat Exchanger" consists of numerous aluminium fins. The "Sandia Cooler" does not need active cooling, instead the cooling block itself rotates at high speed.
Page 1 - Introduction
Page 2 - Basic Thoughts
Page 3 - How does it work?
Discuss in forums [pagebreak]
How does it work?
The principle behind the "Sandia Cooler" can be seen in schematic way in the picture above. The entire cooling block is being driven be a motor which makes the cooler rotate a several thousand rotations per minute. Through the effect of negative pressure environmental air is being sucked into the cooler itself. The cooling block is placed 0.03 millimeter above a fixed groundplate. The dissipating power travels throught the base plate and through the 0.03 millimeter thin air layer to the rotating cooling block. Throughout the a centrifugal effect warm air which first passes the hot base plate move to the inside of the cooler and then passes the fins which are very close to eachother.
Page 1 - Introduction
Page 2 - Basic Thoughts
Page 3 - How does it work?
Discuss in forums