Sandia's Floating, Dust-Free, Spinning Heatsink 307
An anonymous reader writes "Sandia Research Laboratory believes it has come up with a much more efficient solution than heatsink-fan cooling a CPU that simply combines the heatsink and fan components into a single unit. What you effectively get is a spinning heatsink. The new design is called the Sandia Cooler. It spins at just 2,000 RPM and sits a thousandth of an inch above the processor. Sandia claim this setup is extremely efficient at drawing heat away from the chip, in the order of 30x more efficient than your typical heatsink-fan setup. The Sandia Cooler works by using a hydrodynamic air bearing. What that means is when it spins up the cooler actually becomes self supporting and floats above the chip (hence the thousandth of an inch clearance). Cool air is drawn down the center of the cooler and then ejected at the edges of the fins taking the heat with it. And as the whole unit spins, you aren't going to get dust build up (ever)."
Contrarian thinking (Score:5, Interesting)
I'm reminded of the rotary engine [wikipedia.org], used in some WWI aircraft. The crankshaft was stationary -- attached to the plane's firewall -- and the entire engine block, including the cylinders, rotated around it. (The propeller was attached to the engine block.) In this way, no flywheel was necessary (the block was its own flywheel), saving weight, and the engine was cooled naturally, by the air flow over the moving cylinders. I don't know how the engines were balanced.
In a similar manner, the Sandia Cooler moves the heatsink through the air, rather than the air through the heatsink. It's solving a different problem, but I've always been fond of contrarian thinking like this.
dust (Score:5, Interesting)
But...all my fans get a layer of dust on each fan blade. What are they doing differently that will stop this?
Will it work in laptops? (Score:4, Interesting)
Given the possibility of dynamic movement of a laptop during its use, will the Sandia Cooler work inside of a laptop?
Startup/Heat Transfer (Score:3, Interesting)
Maybe I just didn't get the message, but what draws heat away from the die itself? This setup probably does away with thermal paste and similar junctions...
The other thing is that hydrodynamic bearings are only self-supporting and quasi-frictionless after a threshold RPM is reached. Before the whole setup is spinning fast enough for hydrodynamic effects to take over, it's going to grind against the chip die, and unless they came up with something good, it's going to destroy it on startup...
Re:Contrarian thinking (Score:5, Interesting)
But such a heavy rotating mass makes for very unusual handling. When a small force is applied to a spinning disk in one direction a very large reaction happens in the mutually perpendicular third direction. Some fighter pilots would use it to make very very tight left turns, (or a right turn depending on the spin). Sometimes they would use two banks of cylinders counter rotating. Or two engines counter rotating to balance the angular momentum.
Re:dust (Score:2, Interesting)
And as the whole unit spins, you aren't going to get dust build up (ever)
none really?
I think not. Dust is not just 1 thing it is made of of LOTS of things. You smoke? Different kind of dust than what you get if you have cats or dogs, or live in a dry dusty area, or a smogy area, or get a lot of pollen ...
Then on top of that it is different sizes. Then different textures... some is gooy other fine powder. Just depends on what the dust is. Then even if you put a filter over it that only works for a small amount of time. How many people clean those out on a regular bases?...
If it depends on the layer of air they are talking about then it better have a decent filter and expect lots of seized fans...
2000RPM? (Score:4, Interesting)
Spinning a heat sink that weighs several ounces take a much more powerful motor than a plastic fan. I'd expect it's a to harder on the bearings (i.e. less reliable), and requires a lot more power than a traditional heatsink/fan setup.
Re:dust (Score:4, Interesting)
But...all my fans get a layer of dust on each fan blade. What are they doing differently that will stop this?
Your blades also have hundreds of millimeters of clearance between them, not fractions of a millimeter. As well, dust requires an electric charge to stick to something... plastic has a very large static charge that 'grabs' the dust... use a different material and the charge is neutral. Problem solved.
Re:Air is a thermal insulator (Score:2, Interesting)
If your working fluid is moving fast enough, it stops mattering how conductive it is. The Reynolds number starts to dominate all the heat transfer coefficients. The problem with cooling is always the boundary layer, where the fluid stagnates and acts as an insulator. Sandia's found a way to minimize the boundary layer by shrinking the gap between heatsink and fan. Props to them.