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Topic: Project: custom 19in rack passive cooling system - page 4. (Read 14475 times)

full member
Activity: 133
Merit: 100
May 2012: assembling the radiator segments of the center module

Segments assembled with T-connectors removed


One of the ends


Showing the length of all 14 segments


All the segments assembled with the T-connectors attached

full member
Activity: 133
Merit: 100
In April the first set of pump parts from Koolance arrived


The reservoir and primary pump after assembly


Measuring the clearance


The final set of Cape Cora modules arrives. This makes 42 modules in total!
full member
Activity: 133
Merit: 100
It's a neat idea, here are some things to keep in mind:

Those passive radiators are cool and do work, but they're quite expensive and you will need many to dissipate 900W. For about $100-150 you can buy a brand new car radiator that is designed to handle many kilowatts of heat. Slap a big low RPM fan or two on there and it will be dead silent. Make up a nice box for it and nobody will notice it. This will also take up less space than a giant passive radiator.

If you use copper water blocks with those aluminum radiators, you will need to run a mix of coolant that includes a corrosion inhibitor to prevent galvanic corrosion.



Thanks for the input. Yea, the aluminum radiators are definitely a source of concern wrt galvanic corrosion, so I had to use nylon screws and nylon shoulder washers to electrically insulate the modules from the rack. I'll still use a corrosion inhibitor, but should be pretty well covered in this regard.

The Cape Cora modules dissipate 22.5W/ea, so I need at least 40 (the current design has 42 for symmetry)
full member
Activity: 133
Merit: 100
The first set of parts arrived in March.

Unfortunately one of the T-connectors for the radiator modules was damaged in shipping (from Aquatuning in Germany)


Fortunately they sent me a replacement less than a week later.

The aluminum bar stock prior to cutting



The perf aluminum side panels prior to cutting



The perf side panels after cutting shown next to the rack


The first set of mounts after cutting

sr. member
Activity: 452
Merit: 250
It's a neat idea, here are some things to keep in mind:

Those passive radiators are cool and do work, but they're quite expensive and you will need many to dissipate 900W. For about $100-150 you can buy a brand new car radiator that is designed to handle many kilowatts of heat. Slap a big low RPM fan or two on there and it will be dead silent. Make up a nice box for it and nobody will notice it. This will also take up less space than a giant passive radiator.

If you use copper water blocks with those aluminum radiators, you will need to run a mix of coolant that includes a corrosion inhibitor to prevent galvanic corrosion.

full member
Activity: 133
Merit: 100
Hi folks,

I figured that I would share my project with you all in the hope that you get a little enjoyment out of it the way I have.

My primary mining system had to be relocated to a common area at home at the end of last year due to a visitor (read MIL) that has been staying with us since that time following the birth of a child. Normally the fan noise from the GPUs when running full-throttle wouldn't be a concern, but the silly things scream like a banshee which had become detrimental to the WAF for my bitcoin mining, so something had to be done. In the mean time I have had to reduce the fan speed (and correspondingly the hash rate) of my system during daylight hours, and can only run at full throttle in the middle of the night.

To that end, my project has the following design goals:
  • Ability to dissipate >900W of heat load
  • Near silent when running
  • Appealing visual design (remembering the WAF)
  • Modular and serviceable
  • Minimum external components
  • Reasonable cost (funded by mining)
  • Flexible design that will allow cooling of next generation mining hardware in addition to the current GPUs

All this in mind, I started looking into water cooling as some folks have had a measure of success increasing efficiency when mining after doing so. Most of the systems I had seen all used active cooling that use one or more fans to pass air through a radiator and remove heat from the cooling liquid. This would work fine if noise isn't a concern, but in my case I had to find another way. As my research progressed, I ran discovered passive cooling. It has the same heat dissipation benefit of active cooling, but needs a larger surface area to allow convection and ambient airflow to dissipate the same heat load. Fortunately my mining rigs are located in a 19in rack with adequate airflow and space to accommodate a larger surface area radiator array.

I discovered the Alphacool Cape Cora series passive radiator modules which met my design goals and began a design based on them. The initial design required keeping at least two rows of the radiators relatively close to the side of the rack, and the original solid aluminum sides of the rack had to be changed out with something that required some air to pass through to allow effective cooling. Also, the radiator modules would be rather heavy once assembled and filled with cooling liquid, so mounts were needed that could accommodate the weight and maintain rigidity. I went through a few designs over the intervening months, but ultimately settled on Design G (the staggered array design below):

High resolution version here.

Since the plan is to use copper heat exchangers and brass fittings in the cooling loop, the aluminum Cape Cora modules posed a problem wrt galvanic corrosion. To that end, I will be electrically insulating the radiator modules and using a corrosion inhibitor in the cooling fluid.

Since there a multiple pumps and sensors, I settled on the Aquaero 5 XT from Aquacomputer to manage everything. At present only Windows drivers are being released by Aquacomputer, so I might need to spend some time updating the Aquaero 4 Linux port someone did a few years ago.

Free time has been hard to come by, so actual construction has been slow. I have uploaded pictures of the progress so far, and will add more as things progress.

Have fun!
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