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Experiment: Ice in the Reserator!
Written by Freddyfast   
Wednesday, 03 November 2004 07:58

You know those funky silent Zalman Reserators?  They use natural convection to cool the fins that are exposed in air. There's no noisy fan, so they're much quieter than most watercooling. Thing is, have you ever wondered just how well they'd work if you put ice in them? No? Well Freddyfast did, so read on!

When I first saw the Reserator I thought is was pretty cool.  I went with watercooling so I could lower the noise by removing the CPU fan and I know that water is a better medium for removing heat.  I looked at numerous kits, but Zalman’s solution was the one I wanted to use.

The Reserator was the kit I went with because it is easy to install, quiet, and I knew it would be effective.  When you use that much water, 2.5 litres, you can remove a lot of heat. [Ed: Actually, the amount of water you have doesn't relate to how much heat you can remove.]  The surface area of the Reserator is more that any other kit.  They include quality parts.  Even though the original flow indicator was not up to snuff, it was still a good kit.  Zalman voluntarily recalled their flow indicator.  Actually, I was not required to send mine back.  They just sent me a replacement free of charge.  Excellent customer service! Enough of my praise for the Reserator, obviously I like it because I paid a lot of money for it.

I thought of putting ice in the Zalman when I was filling it for the first time; I did not fill it all the way up. Instead I saved some of the demineralised water for freezing.  I have read that the brand of water that is best is Aquafina, as it is demineralised by reverse osmosis.  Just to be on the safe side, I used some Water Wetter too. The water I kept back when I initially filled the system, I then used to make about 6 or 8 ice-cubes.

On its own the performance of the Zalman was okay, but I was not overly impressed.  You know, it kept the CPU cool enough, but it was not a phenomenal “let’s crank this up to 6.7GHz!” kind of cool.  I was not upset, maybe just mildly disappointed with the average CPU temp. What was impressive was the lack of noise.  And I was finally using a water-cooled system.  I always wanted to, but was apprehensive about pumping water around inside my case.  No better time for a few ice cubes.

I had 6 or 8 cubes to throw in.  Adding them was easy - I opened up the lid and dropped them in.  They instantly started cracking, as cold ice cubes do.  The Reserator, as I am sure you are aware, is just a big heatsink.  The job of a heatsink is to transfer heat.  The Reserator does it well.  The ice melted extremely fast.  The cooling fins were cold.  I realized that the Reserator was taking heat from the ambient air and transferring it to the ice and cooler water.  This is why the ice melted so fast.  The ice did not cool the CPU enough to notice.  The ice was gone in less than two minutes.  It was not because the water was so warm.  It was because the Reserator was exchanging the heat from the room so fast.

I knew the ice would melt fast, so I needed a way to insulate the Reserator from the warmer environment.  The Styrofoam package it shipped in would be perfect.  The Styrofoam case is two pieces.  I cut the bottom off the case and taped the two pieces together.  This formed a base for the Reserator to stand in.  In the front half of the case I carved out to holes for the water tubes to fit through.  Now the Reserator would be totally encased in the Styrofoam.  That should protect it from the warm environment and keep the ice frozen longer.


By this time in my computer’s history I have started using the 3.2GHz Prescott.  The Prescott runs hot.  I have one in my work machine too, with stock cooling; it runs between 52 and 68 Celsius.  It is my work machine, so it is not running anything too demanding.  Just the MS Office Suite, a few utilities, and network admin type stuff.

My flow indicator, (the original defective one), had a small leak.  It was time to take it out of the loop, drain some water, and make more ice.

I froze about a litre of water and put the other litre and a half in the Reserator.  The ice was made in a few of plastic cups; two drinking cups and some smaller containers.  So I had some big chunks of ice that would not melt as fast as little cubes.  I put them in the Reserator gently, so as to avoid splashing Water Wetter in my eye.  Those cooling fins were cold.  The ice was cracking big time.  I put the Styrofoam case on and powered up.


Upon boot I went into the BIOS setup to monitor the temp.  20 Celsius.  That’s cold enough.  I rebooted to enter Windows and run some tests, only to be greeted with a lockup.  I reset the computer.  This time it was almost done booting when there was a BSOD.  I thought “Maybe the water tube contracted from the cold and sprung a leak.”  I quickly took the side off my case to discover condensation!  All over the waterblock and tubes was a thick layer of condensation.  It was cold enough alright, too cold.

I shut down everything.  I had to get that ice melted and the condensation gone so I could test my CPU and motherboard in normal conditions.  I could not afford to lose either of them.  I took the Styrofoam case off and went at the Reserator with a hot blow-dryer.  All the ice was melted in less than five minutes.  I booted and all was well.  


I will try this again someday.  I just need to figure for relative humidity, water temp, and air temp.  I found a useful chart at that shows at what temperature condensation will begin to form.  Next time I will use less ice.  

Freddyfast also has small mod that can help the performance of a standard Reserator. See here for more details.

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