So...I have here a PC which isn't worth all that much now (having been built by yours truly back in 2007, and aside from an additional harddrive and a memory upgrade and periodic cleaning of the air filters has been untouched since), and it's been sounding progressively more like a car with a knackered wheel bearing for several months now - even worse at startup as the GPU fan makes a noise like a moped going flat out for the first ten minutes! Basically, every fan in the thing really needs to be replaced.
Even when it was running "quietly" when it started out, it was still noisier than I would have liked. Always fancied the idea of using liquid cooling but back then the ready made kits were utterly stupidly expensive, and being honest I didn't feel that I had that much faith in a tiny DC pump the size of a matchbox that many of them came with.
Also...given that I'd just built the computer (at no small cost!) I wasn't too fond of the idea of mucking around with an idea which had the possibility, no matter how remote of drowning it.
Fast forward six or seven years, and I think it's a more reasonable target for invention. So...I have started accumulating bits.
We have a radiator (which formerly saw service as a heater matrix in a Saab 900).
Obviously the core will be getting a coat of matt black paint to assist its radiative properties at a later stage. The brass bits have been polished because...Well...shiny!
The actual water blocks for the CPU and GPU will be off the shelf components as will the pipework to and from them. I took the decision early on that I wasn't going to muck around with those parts and that I would leave it to manufacturers who know what they're doing. Those have yet to be bought but ones for the CPU at least seem to be pretty readily available. GPU may prove to be more tricky from first glance...but we'll see. If anyone has suggestions on a waterblock to suit the GPU on a GeForce 8500GT, I'm all ears.
The layout I'm going for is a second mini tower case that will be stripped out will be used to contain the header tank (to be scavenged from a car in the local scrap yard or just find a Saab 900 one as that should be about the right shape), pump, flow control valve and control equipment. The only things connecting that to the PC itself will be the coolant lines, which will be isolated by gate valves in the coolant unit so that the PC itself can be easily drained down and the cooling plant isolated and disconnected if it needs to be moved. Taken a leaf out of the A/C system design book there.
Control will be by a unit mounted on the desktop, three indicator lights (scavenged from a scrap Merc 208D van's instrument panel) indicating power on, pump running and loss of flow (haven't worked out 100% how that will be monitored yet, but likely to be a washing machine level switch on a capillary tube I think as I'm hoping to avoid too much head pressure). The space below the indicator lights will likely contain a temperature readout at some point in the future. The switch is a three position type (it's the headlight switch from a Hillman Imp) and will be set up for off/pump & radiator fans low/pump and radiator fans high. Reckon given the surface area of the radiator that I'll probably never need the high setting. Switching will all be done by relays and a contactor that will live in the cooling unit. Contactor will also be set up such that a drop in coolant level will cause it to drop out. Said contactor and all mains wiring save for the actual lead to the pump itself will be inside an IP65 box as well in the finished design. Probably use something like a 9 pin serial or cat 5 cable to connect the control box as I've got dozens of them rattling around and it's all low power stuff.
The one thing which had been causing me the greatest head scratching to be honest had been the circulation pump. I've never really trusted the tiny 12V ones which most of the off-the-shelf watercooling kits seem to come with, at least the ones in my pricerange. So one idea had been to use the heater circulation motor from a Jag XJ6, as it's a pretty meaty bit of kit. It is however a piece of kit with a less than stellar reliability record and not really designed for continuous operation. Noise levels had to be checked as well as it normally lives in the engine bay where that's less of an issue.
Think my pump issues have been solved however. When discussing this with a friend he mentioned that he'd got an old hot water system circulation pump rattling around in a box somewhere which had been changed out years ago. It basically worked, but had started to have issues starting and was making a noise like an angle grinder because it was so scaled up (along with most of the system as someone forgot to add a corrosion inhibitor). Sure enough it was a mess, but a Grundfoss 15-50 130, so a decent pump. Some enthusiastic brute force, feeding it a diet of Cillit Bang and lots of clean water, and poking it with a screwdriver soon got it running well and silently though. All it seemed to need was a damn good clean. Once I've got some 22mm flexible pipe (hopefully tomorrow), I'll be leaving it circulating a bath full of water tomorrow to help clear some more of the gunk out of it and give it a bit of a soak test (no pun intended). Any suggestions for what would be the best thing to use to clean it out with are welcome.
Obviously at full chat it's waaaaaaay overpowered for this, but on low it is barely tickling over and seems quite happy to be throttled back to a perfectly reasonable flow rate with the gate valve on the output side. Damn near silent too.
Looks a bit of a state, but get rid of the smashed plastic rating plate and a coat of enamel black and it'll look the part I reckon.
Think the scheme in the cooling case is going to be basically polished metal and black. The brass end tanks on the radiator having decided that right from the start I think!
More updates to follow soon...
