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Oil-Cooling 802.11 Infrastructure

Posted by timothy on from the unusual-means-admirable-end dept.

gomoX writes "A group of 802.11b fans in Tordera, Spain, are running a wireless node on the roof of a building, with the idea of a free wireless network for everyone on the neighbourhood. Its a system running linux with a home made can antenna, mounted on a plastic tool box in the roof. To keep it cool under the sun and protect it from rain, wind, they have immersed it into vegetable oil (yes, the whole thing). As oil is non-conductive, everything should run fine. The site is in Spanish, here is the google translation and the google cache."

10 of 186 comments (clear)

  1. Re:One Problem... by Gordonjcp · · Score: 4, Informative

    It's not that it retains heat, it conducts heat very well. Diesel would be better, as it's less likely to go "off" and smell, and it has a higher flashpoint.

  2. Actually oil makes it water proof by aduchate · · Score: 5, Informative

    The reason why they used oil is first to avoid the whole thing to get drowned. They reckon that it will avoid condensation water to fry the motherboard... How paradoxal.

  3. harddrives need air. by rebelcool · · Score: 1, Informative
    the read/write head of a harddrive is not unlike that of an airplane wing. It floats/flies micrometers above the surface of the platter on a cushion of air as the platters spin. This is necessary because the platters have microscopic hills and trenches as polishing something perfectly smooth isnt quite possible, and to avoid crashing the head into the platters.

    This is why most harddrives on their labels say "DO NOT COVER EXHAUST HOLES"

    Im surprised it worked for 2 days. Maybe thats how long it took for the air already in the drive to get pushed out the complex baffle filters that are behind the exhaust holes.

    --

    -

  4. Wrong wrong wrong... by TheHawke · · Score: 5, Informative

    They are using the wrong type of oil for their project! For starts the oil is organic and will spoil, making things messy. Veggie oil is, in the family of fluidic heat conductors, a poor performer.

    What they can use and is readily available at any store that sells Amateur radio gear or wholesale electrical supplies is transformer oil..
    It's actually designed to be used in what the RF techs call dummy loads to conduct the heat away from the resistor banks that absorb the RF energy when they test transmitters. The stuff's most commonly used to wick away heat from electrial transformers, both at substations and the transformers hanging on the poles that supply 240 Volt AC to your home.

    One COULD try to build a oil-cooling system on a custom PC, but the heat removal would not be as good as glycol/alchohol/water cooled system.

    --
    First rule of holes; When in one, stop digging.
  5. Re:A better way to do it by tmasssey · · Score: 2, Informative

    The only problem with this is that cable losses at 2.4GHz is enormous. Even with decent quality cable (LMR400) you're looking at 2db for every 10 meters. When you're talking 500mW, that's not a lot to lose...

    --
    Linux IT Consulting and Domino Development in Michigan
  6. Re:This looks tempting. by Anonymous Coward · · Score: 1, Informative

    You can quiet down that buzzy/rattle-y fan by removing it from the heat sink, pulling off the label from the side next to the heat sink, pulling out the rubber disk if there is one, and dripping a drop or two of sewing machine oil in there. Then clean the plastic surface of the fan, stick the label back down, and reattach to the heat sink. This even works for the bigger fans inside power supplies, but it's more work to open up the p/s

  7. Re:Watch that transformer oil! by TheHawke · · Score: 3, Informative

    FYI, for those that are wondering where to get this wonderfluid at..
    Try here

    http://www.mfjenterprises.com/products.php?prodi d= MFJ-21

    They sell it by the gallon and its pricey, but its the real mccoy.

    --
    First rule of holes; When in one, stop digging.
  8. Re:Probably not going to survive long... by Moofie · · Score: 2, Informative

    OK, radiated heat transfer goes as the fourth power of the temperature difference, but the surface dependant constant is pretty darn teeny tiny. But you seem to be talking about convective heat transfer, which (if I remember correctly) is linear with temperature difference.

    In any kind of fluid flow (like, say, an atmosphere) convective heat transfer is going to be orders of magnitude more effective than radiant heat transfer. The best ways to increase convective heat transfer are to increase surface area (fins) or increase the speed of the flow across the surface (fans). The only way to increase the effectiveness of radiant heat transfer (once you've painted it black) is to increase surface area, and the math to make something compact that doesn't radiate onto itself is pretty darn ugly.

    Thought I'd throw in some clarification there.

    --
    Why yes, I AM a rocket scientist!
  9. Tension by aaarrrgggh · · Score: 2, Informative

    Tension is actually a reference to voltage in this case.

  10. About wires by Andor666 · · Score: 2, Informative

    Knowing something about wireless and microwaves should tell you that we use to put the computers on the roof cos' in that signal we send, in 2'4 Ghz, we can loose it all in only 2 or 3 meters of wiring. So, we put it up.

    Here on spain our limit on signal power is 100mW. Lower than in USA as i know. And PigTails are cheaper in USA ;D

    See ya