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feathers · 03-08-2004, 03:58 AM

Hi,

I have worked on several prototype water-chillers. It's definately a worthwhile project! The idea of warm water running through a system sucks big-time! I use a peltier to chill the CPU but still have warm water flowing over the peltier to keep it cool. It would be much better to have chilled water flowing through the cpu waterblock because this would increase the performance of the CPU peltier!

The only negative thing I will say is this: Chilling the water is a waste of time if you don't have a peltier over the CPU as well! A peltier produces very low-temps but only across a small surface area (50mm max).. The most effective place for a peltier will always be directly over the CPU first and foremost. If you can then chill the water as well then you will see a dramatic increase in the performance of the CPU peltier!

Regarding corrosion and different metals: Yes, it can be a problem and you will always need some corrosion inhibitor. I've used anti-freeze but I don't like it. It's an extremely nasty poison and you don't want it evaporating into your computer room! I've also used a de-toxified glycol coolant which the manufacturer claimed was extremely safe! I became ill within 24 hours of using the stuff!

Antifreeze reduces the ability of the water to remove heat although it does help to prevent corrosion. Car windshield washer would be better in terms of cooling performance. It does contain antifreeze (which is why it comes with a warning of serious consequences for exposure) but it also contains a surfactant which reduces the water tension. When you reduce the surface tension of water you will see your CPU temp drop!

I would recommend redline water-wetter. I'm using it in my system now. It's a pink liquid with corrosion inhibitors. Redline water wetter has made my noisy water-pump silent! (I have an old Eheim 1048 with a damaged shaft). The water-wetter is less toxic than antifreeze and it's viscocity is much lower than glycol/antifreeze.

Going back to your water chiller:

If you can chill a thermally insulated container with water and have the water freeze solid.. You could then have the coolant running through this block of ice and this would give you a much better chilling performance. It doesn't take much effort for the CPU to raise the temp of chilled water.. It does require an enormous effort for the CPU to melt a solid block of ice!

Finally.. There is rule you might want to remember with regard to chillers..

The amount of chill you get will be proportional the power of the peltier that's chilling the water versus the waste heat in watts from the CPU.

In other words: If you CPU is generating 90 watts of heat and you use an 80 Watt peltier to chill the water: Don't expect any chilling performance! You really need to double the ratio at least - so the peltier would be 180 Watts for a CPU generating 90W.

If you need an especially high-powered peltier (280Watts) then I can acquire it from our German supplier. If you'd like some pics of the chillers I worked on then email me.

:-)

03-08-2004, 03:58 AM	#2
feathers Cooling Neophyte Join Date: Mar 2004 Location: UK Posts: 81	Hi, I have worked on several prototype water-chillers. It's definately a worthwhile project! The idea of warm water running through a system sucks big-time! I use a peltier to chill the CPU but still have warm water flowing over the peltier to keep it cool. It would be much better to have chilled water flowing through the cpu waterblock because this would increase the performance of the CPU peltier! The only negative thing I will say is this: Chilling the water is a waste of time if you don't have a peltier over the CPU as well! A peltier produces very low-temps but only across a small surface area (50mm max).. The most effective place for a peltier will always be directly over the CPU first and foremost. If you can then chill the water as well then you will see a dramatic increase in the performance of the CPU peltier! Regarding corrosion and different metals: Yes, it can be a problem and you will always need some corrosion inhibitor. I've used anti-freeze but I don't like it. It's an extremely nasty poison and you don't want it evaporating into your computer room! I've also used a de-toxified glycol coolant which the manufacturer claimed was extremely safe! I became ill within 24 hours of using the stuff! Antifreeze reduces the ability of the water to remove heat although it does help to prevent corrosion. Car windshield washer would be better in terms of cooling performance. It does contain antifreeze (which is why it comes with a warning of serious consequences for exposure) but it also contains a surfactant which reduces the water tension. When you reduce the surface tension of water you will see your CPU temp drop! I would recommend redline water-wetter. I'm using it in my system now. It's a pink liquid with corrosion inhibitors. Redline water wetter has made my noisy water-pump silent! (I have an old Eheim 1048 with a damaged shaft). The water-wetter is less toxic than antifreeze and it's viscocity is much lower than glycol/antifreeze. Going back to your water chiller: If you can chill a thermally insulated container with water and have the water freeze solid.. You could then have the coolant running through this block of ice and this would give you a much better chilling performance. It doesn't take much effort for the CPU to raise the temp of chilled water.. It does require an enormous effort for the CPU to melt a solid block of ice! Finally.. There is rule you might want to remember with regard to chillers.. The amount of chill you get will be proportional the power of the peltier that's chilling the water versus the waste heat in watts from the CPU. In other words: If you CPU is generating 90 watts of heat and you use an 80 Watt peltier to chill the water: Don't expect any chilling performance! You really need to double the ratio at least - so the peltier would be 180 Watts for a CPU generating 90W. If you need an especially high-powered peltier (280Watts) then I can acquire it from our German supplier. If you'd like some pics of the chillers I worked on then email me. :-)