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Project: HedgeBox (passive HTPC) Easter update

Discussion in 'Project Logs' started by Tursas, 13 Mar 2007.

  1. ottzen

    ottzen New Member

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    I get your point. But I've never heard of waterfilled heatpipes, and whoever came up with them should have been so smart as to fill them completely with fluid. Unless theyre compensating for some kind of condensation, and in that case one would probably be using the heatpipes wrong.
    I don't get it anyway. Solid copper and its done.

    However...as he's using the mCubed ones and they'll work with all likelyhood, we should just drop it and let room for his mod ;)

    //ottzen
     
  2. nry

    nry Member

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    Looks like a good project, and a good idea. Should be fun taking it apart
     
  3. Tursas

    Tursas New Member

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    These heatpipes should work in any direction. I dont think there is water inside them. I think all the modern heatpipes have wick with somekinda pixie powder inside them. Also they are vacuum filled with some gas. I will let the wise people answer this question. as long as they work im cool with em.

    I got these heatsinks from Ebay. This one electrical retailer was cleaning their office and they had box of these lying around. £20, not bad. They are made by Aavid Thermalloy.

    For holesize on the wood, I think I just need to get the wood and check how it looks and how much is the internal temperature. I wont put any fans inside.

    I managed to finish off all four wings! I will post pix soon.
     
  4. Tursas

    Tursas New Member

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    Oh yeah....

    The IO holes is bit "interesting" there is enough of space inside the case to plugin the cables. So I will have all cables running trough the wooden bit on the bottom. A bit of a fiddle, but it will keep the case intact (and I dont need that often to pull cables on that)
     
  5. gnidnu

    gnidnu Beware of the Tofu!

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    This looks great, except for the mesh. Long notches would look better imho.
     
  6. Dreamslacker

    Dreamslacker New Member

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    Earlier generation heatpipes sometimes used water in them. The heatpipe is partially filled with water and subsequently vacuumed to leave negative pressure in the pipe.
    Under the negative pressure, the water will boil below what it would at normal atmosphere.
    The water can also be mixed with alcohol to lower it's boiling point. Alternatively, some kind of gas can be pressurized to change into liquid within the heatpipe.

    These types of heatpipes depend on gravity for the liquid to return to the heated portion.
    Newer heatpipes use sintered wick or a bunch of wires or so to make use of capillary effect to allow the liquid (when it cooled on the other end, the gas will condense) to return to the heated portion regardless of orientation.

    Because heatpipes use what is effectively phase change to transfer the heat, they're very different from just a copper rod.
    A liquid needs to absorb a large amount of heat in order to evaporate. In doing so, the gas will move through the pipe to the other end (usually embedded in a heatsink) and transfer the heat to the body/ fins of the heatsink.
    This allows the gas to condense into a fluid and move back to the heated portion.

    This doesn't allow you to go below ambient because it's effectively a passive process.
     
  7. Tursas

    Tursas New Member

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    Hello again!

    I found a good way to grind pieces off from the heatsinks. I need to take of these bits in off so I can mount the frame inside.

    Having destroying around 5 disks per block I wanted to make the cutting more precise and faster.

    [​IMG]
    Bench drill stand + £2 fleamarket vice + Proxxon highspeed drill. Heatsink itself is mounted to a X-Y vice.

    [​IMG]
    Smooth and straight......... :dremel:

    I finished of drilling the holes for the copper rods.

    [​IMG]
    Ahh... almost 10kg of aluminium enjoying afternoon sun.

    More updates later. I will leave tomorrow for one week trip. So I will continue then.
     
  8. Hazer

    Hazer In time,you too will be relixalated

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    Just to follow on the well-done explanation from dreamslacker:

    Although the different generations of heat-pipes use different liquids/gases, the result is the same. They work in the same way. The different medium just increases its effectiveness:

    The liquid sits on the bottom of the pipe where your heat-source is. The liquid then heats-up (and some evaporate which works even better) and through convection rises. The heated coolant then collects at the top of the heat-pipe where the heat-sink is and instantly cools down since ambient is always cooler than the heat-source. This then cools down the coolant and creates the 'dew' effect where the cooler liquid then drips down the heat-pipe. It is actually even 'pushed' down since the hotter coolant is pushing its way up.

    By putting in a 'wick' or a 'mesh', you get the capilary effect that the liquid will help 'defy' gravity and not make the orientation of the heat-pipe so important.

    IMO, the 'wicked' heatpipes are only good for northbridge cooling. The wick solution for heat-pipes does not truly compensate for the gravity effect. The 2 forces that make heat-pipes work is Convection (the greater force) and Gravity (actualy the lesser force). Capilary force only works against Gravity under a fractional amount. For northbridge cooling, this is sufficient. Most northbridge cooling can get away with direct passive heatsinks anyway.

    The air-vents for general cooling of the internal air-space is a great idea. Just remember this: Convection rules all. You need vents on the bottom for the cool air to come in, and vents on the top for the hot air to escape. The heating of the air by the components creates the Convection (hot air rises). The hot air drives itself upwards. It is replaced by the cool air being pulled in from the bottom (the hot air has to be replaced by something). This is a VERY common practice used in industrial cooling. The one big problem with your design is this: Your picture shows your mobo slanted so the hot air will rise into it, not away from it. You really should change the orientation of the mobo by 90 degrees. I would rotate the whole thing CCW by 90 degrees, putting the HDD on the bottom left and making airvents just for that compartment for the HDD.

    Second, I would make certain the heatpipes traveled upwards at all costs. Even if the capilary effects were adequate, your current design transfers the heat toward the bottom of the case so that the bottom heatsinks are now disapating the heat into the air that is coming in. In effect, your sending the heat you just displaced from your heat sources directly back at them in the form of Convection of hot air.

    It would really suck to ignore the basics and do all the hard work of bending all that heat-pipe just to end up with heat issues.
     
  9. Tursas

    Tursas New Member

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    Happy Easter to all!

    Thanks Hazer for really enlighting info of heatpipes and convention. I have decided to have motherboad facing up. Saves me loads of hassle.

    I have been back on a workbench and got some nice results. I managed to finish of the main frame. Im quite proud of it. No external bits used to attach heatsinks together. All hidden inside.

    [​IMG]
    I made studs out of 8mm aluminium rod and hammered them into center heatsink.

    [​IMG]
    Hammering rest of the heatsinks to the centerbit will ensure a snug fit.

    [​IMG]
    Screwed in the threaded copper rods.

    [​IMG]
    Finally ready!

    [​IMG]
    [​IMG]
    Plenty of area to cool off.

    [​IMG]
    I made the support for the mobo. Starts to look slowly like a computer.
    You can see how I can access the IO ports.

    Next in line is to put few supporting frames. Then I can start testing with the heatpipes. I also need to order the woodenbits and clean the heatsinks.
     
  10. BagUd

    BagUd New Member

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    Thats just awesome ! :rock:
     
  11. zhangmaster12

    zhangmaster12 New Member

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  12. Pre_Tender

    Pre_Tender New Member

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    Damn... that's just awesome

    i wonder what the spec's are going to be,
    in temperatures that is

    But Damn...what an idea
     
  13. dacust

    dacust What's a Dremel?

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    I was thinking awesome as well. So that's 3 awesomes and one sexy.

    Cool to see it take shape. Obviously it's sturdy!
     
  14. itsjustacompaq

    itsjustacompaq Member

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    simply amazing!
     
  15. MageOutlaw

    MageOutlaw New Member

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    that is on AMAZING!! rig man i can not wait to see this thing done
     
  16. Tursas

    Tursas New Member

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    Thanks guys for all the awesomes and sexys!
    I cant wait either to have this thing ready....still long way to go.

    Tomorrow I will continue and post more pics.
     
  17. V3ase

    V3ase New Member

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    gret looking , keep work, i like it beous its look like erly prototypes of x box
     
  18. Bluephoenix

    Bluephoenix Spoon? What spoon?

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    with all the metal on that, MetalliX seems like a better name, but ultimately its up to you.

    Great idea! Can't wait to see how it turns out! (hopefully not with the magic smoke getting out)
     
  19. dream caster

    dream caster just lurking from out there

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    First time I read your thread; nice design but why don't you put motherboard vertical or almost vertical so connectors , from motherboard and cards face the downside void of the X; also in this way you can put heatpipes to both sides of motherboard.

    You may want to look at a russian article about a zero fan case that is a translation from http://casemods.ru/section15/item210/. They show some very interesting techniques. Some of them are in the article, some are in links that were not put into the translation last time i read it; to find them you would have to go through the awful translations from Babel fish and Google and click links; best to look at both authomatic translations side by side.
     
  20. Altron

    Altron Well-Known Member

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    I must say, that's a really classy and well put together project.
     

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