Perhaps someone will run a CFD model (on a cluster perhaps)…. And the alliteration in the subject could be improved.. …Conduit Cuts Computer Center Cooling … I can’t think off hand of C words for “needs by 90 percent”
From: Beowulf <beowulf-boun...@beowulf.org> on behalf of "beowulf@beowulf.org" <beowulf@beowulf.org> Reply-To: Prentice Bisbal <pbis...@pppl.gov> Date: Friday, January 25, 2019 at 12:57 PM To: Eric Moore <eemo...@fyndo.com> Cc: "beowulf@beowulf.org" <beowulf@beowulf.org> Subject: Re: [Beowulf] A Cooler Cloud: A Clever Conduit Cuts Data Centers? Cooling Needs by 90 Percent Eric, I was suspecting that might be the case, but the explanations in the other articles were way too vague to be sure of that. The NextPlatform provided much better pictures. If that's the case, this thing operates like a direct-expansion (DX) refrigeration system, where the refrigerant is air and does not change state from liquid to gas, like a typical DX refrigeration system, and the induced-draft fan provides the shaft work, and those tiny channels that allegedly line up the molecules act as many tiny offices for the throttling process. Based on the pictures in the Next Platform article, here is a crude drawing of cross-section of one of these devices that I drew in Google Draw. It should help you understand what's going inside this thing: https://docs.google.com/document/d/1UK94PxVlQtVSb2ns5TbCqHjPJ1vYSOmkGSeSorvHyaM/edit?usp=sharing Given this design, you can only have an induced-draft fan on the outlet. A forced-draft fan on the inlet would compress the air, heating it up and negating the throttling (or Joule-Thompson) effect on the low-pressure side. At the end of the day, thermodynamics still says X amount of shaft work has to be done to provide Y amount of cooling through this process, so I'm still skeptical of it, especially at scale. And for those of you looking for something really boring to read rather than work, here are the related patents. I haven't read them myself. https://patents.google.com/patent/US8414847 https://patents.google.com/patent/US8986627B2 https://patents.google.com/patent/US10113774B2 Prentice On 1/25/19 2:26 PM, Eric Moore wrote: Actually, it looks like Joule-Thompson cooling to me (Especially given the "Joule Force" name). You've got the air intake (ambient), then an expansion nozzle, into a low-pressure region, which is created by the fan at the end. So the outlet velocity of the air (and thus it's kinetic energy) is higher than the inlet velocity, which would lower the internal energy, and thus the temperature. Instead the fins/nozzle/heatsink transfer heat to the expanding gas, which exits a little above ambient temperature. I imagine the drawback is you really need to get rid of that high velocity hot air, and can't recirculate it, or the kinetic energy would be converted back to thermal energy, and mess it all up. The descriptions do all involve the exhaust air being ducted to the outside. This article has the most technical detail: https://www.nextplatform.com/2018/12/04/the-leading-edge-of-air-cooled-servers-leads-to-the-edge/ On Fri, Jan 25, 2019 at 11:33 AM Prentice Bisbal via Beowulf <beowulf@beowulf.org<mailto:beowulf@beowulf.org>> wrote: You all know how much I like talking about heat transfer and server cooling, so I decided to do some research on this product: Here's their website: https://forcedphysics.com and here's their YouTube channel with 5 videos: https://www.youtube.com/channel/UClwWeahYGuNl0THWVz1Hyow/videos This is really nothing more than an air-cooled heatsink. I'm afraid I'm going to have to call BS on this technology for the following reasons: 1. It still uses air as the primary cooling medium. I just don't think air has adequate thermal conductivity or thermal capacity to serve modern processor, no matter what you do to it. 2. In the videos, they present highly idealized tests with no control to use for comparison. How do I know I wouldn't get the same results doing the same experiment but using a similar duct fashioned out of sheet metal. 3. Using this technology means a complete redesign of your server hardware and possibly your racks. 4. None of the information in the videos or on their website really explains how this technology works, and what really differentiates it from any other air-cooled heat sink. Most people with a good invention are usually excited to tell you how it works. Since they brag about 30 international patents for this, there's no need to try to protect a trade secret. 5. This statement: The fins work like teeth in a comb, neatly orienting air molecules to point in the same direction and arranging them into columns. Based on my education, this statement seems to be completely devoid of science. This statement seems to defy the laws of physics. Last time I checked, unless an atom or molecule is at absolute zero, it has movement, whether it's spinning or vibrating, or both, so how can they get air molecules to line up all in neat little rows, where the molecules are all pointing the same way? This also implies very laminar flow. As fluid velocity increases that the diameter of the channel decreases, the Reynolds Number increases. As the Reynold's number goes up, turbulence increases, so mathematically, I would expect this flow to be tubulent, and not laminar. From my classes on heat transfer, turbulent flow around the heat transfer surface increases heat transfer, so laminar flow in this case wouldn't be a good thing. Until they can provide better comparisons with real servers in real data center environments, I'm going to classify this as "snake oil" https://en.wikipedia.org/wiki/Snake_oil Prentice On 1/24/19 3:54 PM, chuck_pet...@selinc.com<mailto:chuck_pet...@selinc.com> wrote: Well, this is interesting. "According to Forced Physics’ <https://forcedphysics.com/ [forcedphysics.com]<https://urldefense.proofpoint.com/v2/url?u=https-3A__forcedphysics.com_&d=DwMFAw&c=-_uRSsrpJskZgEkGwdW-sXvhn_FXVaEGsm0EI46qilk&r=fawF3TRTwCqlaBkoLcxYCr4F4NRwCc64hmEgi9rHPpE&m=zr6lAlVphGxOQTXSElww9hGpqb9IZPik0_MN2v8Fqjs&s=lb4Hi9X8NKIYWe_e1RU3Cw4gr9Uz_B7n5pnCNY0ss3U&e=>> chief technology officer, David Binger, the company’s conductor can help a typical data center eliminate its need for water or refrigerants and shrink its 22-MW load by 7.72 MW, which translates to an annual reduction of 67.6 million kWh. That data center could also save a total of US $45 million a year on infrastructure, operating, and energy costs with the new system, according to Binger. “We are solving the problem that electrons create,” he said." A Cooler Cloud: A Clever Conduit Cuts Data Centers’ Cooling Needs by 90 Percent https://spectrum.ieee.org/energy/environment/a-cooler-cloud-a-clever-conduit-cuts-data-centers-cooling-needs-by-90-percent [spectrum.ieee.org]<https://urldefense.proofpoint.com/v2/url?u=https-3A__spectrum.ieee.org_energy_environment_a-2Dcooler-2Dcloud-2Da-2Dclever-2Dconduit-2Dcuts-2Ddata-2Dcenters-2Dcooling-2Dneeds-2Dby-2D90-2Dpercent&d=DwMFAw&c=-_uRSsrpJskZgEkGwdW-sXvhn_FXVaEGsm0EI46qilk&r=fawF3TRTwCqlaBkoLcxYCr4F4NRwCc64hmEgi9rHPpE&m=zr6lAlVphGxOQTXSElww9hGpqb9IZPik0_MN2v8Fqjs&s=VuDTSuinKPMpF6NCztFZkSGOVo3LD7MLjroIj_sn0ao&e=> Chuck Petras, PE** Schweitzer Engineering Laboratories, Inc Pullman, WA 99163 USA http://www.selinc.com<http://www.selinc.com/> SEL Synchrophasors - A New View of the Power System <http://synchrophasor.selinc.com<http://synchrophasor.selinc.com/>> Making Electric Power Safer, More Reliable, and More Economical (R) ** Registered in Oregon. _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org<mailto:Beowulf@beowulf.org> sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org<mailto:Beowulf@beowulf.org> sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
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