Gus Wirth wrote: > Ralph Shumaker wrote: >> Gregory K. Ruiz-Ade wrote: >>> On Oct 3, 2007, at 7:46 PM, Richard Reynolds wrote: >>> >>>> you didnt say here what type of video hardware you have but when my >>>> beyondtv(widndows variant) started rebooting i learned that the fan >>>> on my video card had failed while it appeared to spin, and was clean >>>> it was not working took a while to track down, but it was a fast fix >>>> once i figured it out >>> >>> I very purposefully purchased a fan-less graphics card with a big fat >>> heatsink on it. While doing a physical inspection of the system >>> during diagnosis, I noticed there was no dust on any of the internal >>> components, just on the intake grills and the fans themselves. >> >> Does anyone make a case that does not pull air in from the outside? >> This is the source of most of the dust. > > For some specialized systems such as mini-ITX, yes. Also some industrial > PCs. > >> With all the cooling aids that I've seen now, I don't think there is >> much need to continue to pull air in from the outside. The one cover >> that comes of to give access to the guts of the PC could have a large >> version of that radiator-like cooler with fins on the interior for >> gathering heat and fins on the outside for expelling heat with the >> coolant tubes making the transfer even more efficient. A fan inside >> (mounted near the top, but not mounted to the fins of the cover) could >> blow hot air down the interior fins while a fan outside (below the >> exterior fins) could blow cool air up the exterior fins. The power >> supply could do something similar. The only dust would be on the >> exterior fins and fans (*away* from the electronics). And if done >> well, the exterior fins could be easy to clean. Am I way off? Is >> this just wishful thinking? > > It's doable. Things like water cooling and heat pipes show the trend > toward passively cooled systems. The real problem is ensuring good > mixing of the air inside the case and having enough surface area. A > couple useful equations I've used: > > delta T (degrees F) = 3.16 x Watts / Cubic Feet Minute air flow > Thanks to <http://www.chassis-plans.com> > > Power (watts) = k x Area (meters squared) x delta T (degrees kelvin) / > thickness (meters) > > where k is thermal conductivity in Watts/meter-kelvin > > A sample k value for steel (AISI 1020) is 65, aluminum (alloy 1100) is > 220 and copper is 380. Diamond (type IIa) is 1850. You can see this is > why heat sinks are made mostly of aluminum and copper until diamond > becomes more affordable.
<heh> But that makes me wonder: is diamond actually used anywhere for its thermal conductivity advantages? Regards, ..jim -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
