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Hardware Hacking Upgrades Build

Using a House's Concrete Foundation To Cool a PC 465

Posted by timothy
from the thinking-deeper-than-built-in-cable-drops dept.
Agg writes "Well the slab gets poured on Wednesday so I thought I would sink 6 meters of copper pipe in the slab so that I can run my water loop through it when the house is finished. I hope to have water year round at about 16deg [about 61F]. No need for radiators or fans with chilled water coming straight out of the slab!"
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Using a House's Concrete Foundation To Cool a PC

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  • erm.... (Score:2, Interesting)

    by Anonymous Coward on Wednesday August 26, 2009 @02:46PM (#29205807)

    Doesn't the house shift and settle? Won't a standard 1 + 1/2 inch copper pipe break during that time?

  • by seanadams.com (463190) * on Wednesday August 26, 2009 @02:47PM (#29205839) Homepage

    The steel rebar and the copper pipe being in close proximity will make them act as electrodes on a battery. This will cause the steel anode to slowly be destroyed by the chemical reaction.

    Is it a practical concern in your case? I doubt it, but if they haven't poured yet, it wouldn't hurt to wrap the copper pipe in some PVC tape. This will reduce the thermal coefficient though. Maybe just do it where it passes within a couple inches of the rebar.

  • by rolfwind (528248) on Wednesday August 26, 2009 @02:59PM (#29206101)

    Why? It's very similar to what they do when laying radiant heat into the floor (which is very nice btw, over ducted heat, helps with breathing problems).

    Also, like a previous comment suggesting, maybe you should look into radiant heat tubing over copper.

  • Re:WTF? (Score:3, Interesting)

    by chill (34294) on Wednesday August 26, 2009 @03:15PM (#29206377) Journal

    He lives in northern Tasmania, not Hawaii. I believe freezing -- or hard freezes -- are fairly rare there. Even then, copper embedded in concrete has been used for many decades and it isn't as big an issue as you seem to think. http://www.copper.org/applications/plumbing/benefits/benefits_main.html [copper.org]

  • by Anonymous Coward on Wednesday August 26, 2009 @03:17PM (#29206413)

    I live in the midwest, and did the same thing 4 years ago, when I had my house built... I use a heat-pipe to fluid thermal exchanger on my ESXi server as well as my gaming rig.

    It will in no way harm your resale value, and if your inspector has a brain, it has no impact on the inspection...

    Due to expansion and contraction concerns, I had that small (8`x8`) portion of the concrete isolated....

  • Re:Ice cooler! (Score:4, Interesting)

    by Moryath (553296) on Wednesday August 26, 2009 @03:26PM (#29206579)

    Scratch that. Greater detail on the pics.

    He's barely going down at all. Maybe two feet deep, tops. His slab, at that depth, is going to have an insignificant (less than 15F) temperature difference with the external.

    Now if you go down SIGNIFICANT distance, you can reach an earth-neutral temperature. The further down you go (until you reach a stable point, which will depend on your local ground type) the cooler you will be.

    If he were to go down 10+ feet or so, and then set up the circuit like he is indicating, it wouldn't be too bad. As it stands, he's gonna have one of the most inadequate foundation slabs I've seen in any case, and his "copper pipe cooling" is not going to give him nearly the cooling he is hoping for. I hope to god he isn't in an area with frequent foundation shifts, or he's fucked as it is, copper piping or no.

  • by Brigadier (12956) on Wednesday August 26, 2009 @03:31PM (#29206645)

    I care;
    a.) how much copper, btw doesn't concrete corrode copper which is the reason why it isn't placed in the slab anyways.
    b.) for each layer of piping you put down you need an additional 3 inches of slab. proper embedment really requires 3" of coverage else the concrete will crack.
    c.)concrete curing is an exothermic reaction and it takes your typical slab at least a year to completely cure.

    Here is the best part, I'm assuming your in a cold climate with a reasonable frost line (otherwise this would be a stupid idea). If the water in teh pipes stop circulating and freeze it will crack the pipe and the concrete and cause I nice leak. again weakening the concrete overall stress.

    I'm IAAAA ( I am an actual architect) so heed the warning. Or do it properly.

  • by BetterSense (1398915) on Wednesday August 26, 2009 @03:32PM (#29206647)
    I'm a graduate student in materials science and I can tell you that recent graduate-level textbooks are beginning to state that "degrees kelvin" is acceptable usage. You can also find it all over the literature. Since I've never really heard a satisfying argument as to why "degrees Kelvin" is confusing, unclear or anything else, I'm ok with either usage.
  • by natehoy (1608657) on Wednesday August 26, 2009 @03:38PM (#29206737) Journal

    I rented a house in Kentucky that had this problem. The house was built with copper pipes embedded in the foundation for water, but to save money apparently the builder had just put bare copper pipe instead of putting it in plastic conduit. About 5 years after the house was built, the pipes started failing (in my case, it was a pipe that led to an outside faucet I never used, and I only discovered it when my water bill went from its normal $20 to about $280 one month).

    Fortunately, the landlord in my case was the builder, so he sent a team out to reroute all the pipes up through the ceiling (which was a major mess, but the workers were really careful with my stuff and used sheet plastic generously to contain all the drywall dust, etc) and refunded my water bill for the month. He also replaced all the carpet in the house, since the workers pretty much ruined the carpeting running the new water pipes. So after a week or so of hassle, I had a freshly-painted house with brand new carpeting.

    Apparently (as it was explained to me by the landlord) bare copper *can* sometimes work in concrete, but it depends on the acidity of the concrete, which probably depends on the stone and filler used. The landlord admitted he messed up and didn't measure the acidity of the concrete (and he had built and sold a lot of houses in my neighborhood, so he was looking forward to a LOT of repairs like this).

    In any case, lining the copper with something is probably a good idea, even if it does reduce heat exchange. Or just use radiant heat pipe as the parent suggests.

    After all, there's the heat generated by a computer (maybe 150 watts) to deal with, and 6 meters of pipe. With that much pipe, just the copper exposed to air would probably dissipate enough heat without needing forced air, so exchanging the heat through plastic into a concrete biomass should work just fine.

  • Re:Very clever idea. (Score:5, Interesting)

    by Itninja (937614) on Wednesday August 26, 2009 @04:14PM (#29207325) Homepage
    There is a data center in WA state that keeps half of its' property as vacant land for the sole purpose of using it as a giant heat exchanger. Looks like about an acre. They have piping about 16 inches underground throughout the field. I am told it works great.
  • Re:Ice cooler! (Score:4, Interesting)

    by Moryath (553296) on Wednesday August 26, 2009 @04:23PM (#29207465)

    PS: rechecked location. He's in Tassie, Australia. Very coastal, very similar temperature-wise to coastal US temps. Yeah. This is gonna be REAL disappointing for him. The laws of thermodynamics, much like gravity, don't play very well with wishful thinking.

  • by Anonymous Coward on Wednesday August 26, 2009 @04:30PM (#29207577)

    why does the "outside the concrete" link go to a story about spinach pizza?

  • Re:Very clever idea. (Score:5, Interesting)

    by hairyfeet (841228) <bassbeast1968@@@gmail...com> on Wednesday August 26, 2009 @04:36PM (#29207697) Journal

    That is why I wondered why some data corp hasn't bought up the old Titan 2 missile silos we have here in AR and turned them into datacenters. They are VERY deep in the ground, so you have natural cooling there, they are on the side of a mountain with lots of wind, more cooling, and if you put the racks into the silos themselves you could have fresh air blowing straight up and out through the silos. there are also lots of fiber lines running through that area, including dark fiber left by the telecos during the dotbomb. Not to mention with those big steel doors and hardened everything breaking into your data center would be pretty damned difficult, if not impossible. Oh and we have nuclear power here, so electricity is cheap compared to surrounding states.

    It always seemed to me that with datacenters needing so much cooling these would be a natural fit. The military has done all the hard work, and from what I heard they sell them pretty cheap. One guy even bought one and turned it into an underground house for his family. Just always seemed to me to be the way to go.

  • Re:Mod parent down (Score:3, Interesting)

    by smellsofbikes (890263) on Wednesday August 26, 2009 @05:01PM (#29208079) Journal
    I may be wrong about this, since I'm neither an architect nor a structural engineer, but my understanding was that the 3" requirement was for where steel or iron exited the concrete to the outside, as local water infiltration and rust buildup at the concrete/steel/air interface would cause the concrete to crack. Where the steel is contained fully within the concrete the clearance is way less because the assumption is that the steel is in anaerobic conditions. That's just what I learned when I was doing concrete work.
  • Re:Very clever idea. (Score:3, Interesting)

    by omeomi (675045) on Wednesday August 26, 2009 @05:19PM (#29208341) Homepage
    I wonder why they didn't just drill down?
  • Re:Very clever idea. (Score:3, Interesting)

    by nametaken (610866) on Wednesday August 26, 2009 @06:27PM (#29209369)

    Cost of getting them up to code for a regular workplace, I'd guess. Most of them are badly dilapidated, no? Plus a tech co with those resources probably wants to be closer to centers of skilled techie personnel.

FORTRAN is a good example of a language which is easier to parse using ad hoc techniques. -- D. Gries [What's good about it? Ed.]

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