|MadSci Network: Engineering|
This is a very fun idea. It's not going to be an easy project, but could be a great deal of fun with a reasonable chance of success. The old Cray supercomputers used such a cooling system and there are in fact commercial products that do exactly this. One is Fluorinert made by the 3M company. The fluid will have a high dielectric and high resistivity as required for the immersion of electronics. However, these fluids require special care in there use, maintenance and disposal. I would not recommend using them without proper training and knowledge. So is it possible to do without bringing a potentially hazardous chemical into your home? Maybe. It is possible that a mineral or vegetable oil would have the desired properties and also prove to be easier to work with. High voltage transformer oil may also work, but again you'll need to be sure that the exact flavour you have is benign to work with. Remember that despite your best intentions, inevitably some will leak or spill(potentially a huge amount!). I think the biggest problem you'll encounter with regards to the substance is finding it in the correct purity. While the oil itself may be ideal, most easily available products will have other junk mixed in that will have adverse effects. The biggest problem in practice that I see is that you'll have a large vat of oil to deal with. Changing parts and maintenance will be difficult and potentially very, very messy. Aside from leaks, that's another reason to use a safe liquid. Anytime you need to work on the system it will be much, much easier if you do not have to be concerned with the health and/or environmental risks. It will also be quite heavy and potentially difficult to move around. My suggestion here would be to buy a fish tank. On the bright side... I imagine that the ambient heat exchange between the oil and the outside environment should be enough that you can use simple conductive/convection cooling. ie, just stick the hottest part at the bottom of the tank. The oil heats, rises, cools, and descends. If you really need it, you can rig an external circulation system to either pump the oil through a cooling system or to pump coolant through the oil. The simple solution here would be to buy an old refridgerator. You may also wish to have a thermocouple to measure the temperature at the CPU where it is most important to be cool. All of this being said... I am aware of people trying to do this. There are rumors of success, though I've never actually seen it work in person. Have a look at http://oilcooledcomputer.com/default.aspx I have no idea how successful these guys were (I tend not to believe things I read on the internet), or if their end product would be stable enough for a long term system, but it looks fun. --------------------------- Michael S. Pierce Materials Science Division Argonne National Laboratory
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