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Dell To Sell Advanced Server Cooling Systems
Mitechsi writes "Dell has struck a deal with Emerson to sell advanced liquid cooling systems and services to data center owners. One type of supplemental cooling technology is called the Liebert XD. The XD consists of refrigerant-filled pipes that snake around the server racks in a data center. The liquid system cuts the cooling power load by about 30%–50% compared to other types of cooling systems."
Flood the server room with vegetable oil.
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You know those nifty heat pipes in fancy heat sinks?
Imagine that on a bigger scale.
[Fuck Beta]
o0t!
The ZDNet article is, unfortunately, very scant on details when it comes to our XD (short-hand for "eXtreme Density") system. For one, they give the impression that cooling coils are water-based. They're not; they're refrigerant, just like a whole-house air conditioner. The specific coolers they seem to be referring to are the XDV, an 8kW unit which mounts directly to the top of the rack, and/or the XDO, which is a 16kW unit which hangs in the center of a cold aisle. Just like an air conditioner, hot air is sucked in at the top/side, run across the evaporator coil (cools the air, boils the refrigerant), and cold air is then shot downwards towards the front rack face. The hot refrigerant makes its way back to a heat-exchange unit (an XDC chiller or XDP pump), where it dumps the heat into the rejection loop. This could be anything from a building chilled-water system, to roof-mounted drycoolers, or even a subterranean geothermal system. For a better idea of just what the thing is (and to see lots of pretty graphics and thermal images), the family "sales glossy" lives here(PDF).
Why call it "Liebert XD" ? What, it's not water ?
Ummm, because it's made by the Liebert Corporation? And it's their "XD" line of products?
Is this the first time you've ever heard of branding?
You might as well ask: "Why call it 'Toyota Camry'? What, it's not a car?"
it's still just liquid cooling, something that existed in the server room long before Michael Dell ever sold a single server machine.
So? Cars have been around a long time, too. That doesn't mean I want to drive a Model T.
Anyway, the news here is not that there is a new HVAC product, but that Dell is going to be selling HVAC systems to datacenter owners.
Also, this system uses a gas/liquid phase-change cycle, and it operates on a different scope (zone and spot cooling -- doesn't get anywhere near the CPU), so it's really not like what most people would think of as liquid cooling systems for computers. It's just a way of getting the cooling closer to the heat source instead of blowing cold air around in ducts, such that your HVAC operates more efficiently.
Sure, this idea has been around for a while (though this system makes some improvements that are especially helpful for datacenter use). The news is that Dell is selling it.
The refrigerant-based approach is an efficiency disaster. Any serious datacenter is cooled with chilled water, or it is using double the watt/ton of cooling it should be. A datacenter that is not using water based cooling and some form of freecooling, which saves money even in climates like Phoenix or Atlanta in a 24/7 flat-load datacenter situation, should be sued for false advertising if they claim to be "efficient." There is benchmarking data available on this - a closed-loop dx system is an energy disaster, no matter how slick it looks. And don't even bring up "Well, they're just like a bunch of little chillers" until you find me a 10 ton* centrifugal compressor or an 80 ton rack (or 150 ton if you don't want to be locked into using a Turbocor compressor based unit).
The chilled water coil on the back of a rack is an excellent solution, and a good approach to dealing with the 12 kW racks that datacenter clients are starting to throw at us HVAC engineers. It is also something that has been offered before by IBM and others, and can be custom fabbed up if you have a large, controlled layout facility (co-los are too chaotic to pull off a custom solution in my experience).
As mentioned elsewhere, this is hardly cutting edge. Checkout the Datacenter Design Sourcebook here (I'm biased towards this since it summarizes my thinking as of last year and little has changed, other than a bit more data on the impact of speed controlled server fans impacting the operational approach to hot/cold aisles).
*1 ton = 12,000 btu/hr, I think in Burmese units thank you. And on a similar tangent, you'll pry Fed standard 209E cleanroom ratings from my cold, gowned hands.
Of course there are several other very important reasons, but lets start there. I work for one of the larger Web Hosting companies in the country (we are actually global but that is another story). One thing you don't find in a back lot behind the K-mart is the top ten tier-one providers converging in one spot. The backbone needed to host things bigger than mom and pop websites is enormous and not readily available for most locations.
"which would all be solved by leaving every other rack empty and renting twice as much space."
Um, no. The thermal mass of stacking servers on top of each other is very hard to overcome, regardless of space between racks. You could, however leave a U (the measure of rack space) free between each server (like we do).
"and enough thermal mass in all that air that you can run the AC full blast at night (when it is more efficient because the coils outside are in cooler air) and let the temp rise slightly over the day."
Gee, wonder why no one ever thought of that. Maybe because you have _no idea_ how much heat a room of servers generates? Rise slightly over the day? Surely you are kidding. Adding two stories of empty space you have pre-cooled might buy you a half hour if you shut off the AC. Then you will have an oven, with servers kicking off left and right.
I can go on and address the rest of your points, but the more I think about it, the more it seems I'm responding to Fud.
Experience teaches only the teachable. -AH