Successfully dissipating 1.8kW of heat

[Meathead]

So I'm working on a summer project constructing a cooling system to dissipate 1.8 kW of heat put out by 16 rows of transistors. The chips themselves only need to stay under 100C but my goal is staying within 50-60C to simulate real world conditions. There will be 8 cold plates in series being used.

The cold plates to be used are the 4-pass plates:

http://www.aavid.com/sites/default/...pdf/liquid-cold-plate-datasheet-hicontact.pdf

Some friends working on the same project wanted to order this for the heat exchanging unit:

http://www.digikey.com/catalog/en/partgroup/wl-series/36412

I'm thinking it would be cheaper and easier to upgrade to handle more cooling capacity in the future if I just put together like 3-4 120.4 radiators and 2-3 pumps. I have an 800 watt power supply laying around that would work perfectly for this build. The piping will be entirely 3/8" copper tubing. The total length of the system tubing should be under 20-30ft.

Any thoughts on the viability of this? I would love to hear any input. I feel that the raddage will be more than enough. The only thing that really worries me is if 2-3 watercooling pumps will be enough to feed all 8 cold plates in series. These blocks are different then standard water-cooling hardware but I feel like they would be less restrictive.

 

[Bobnova]

Automotive radiator. Cheap, massive, capable of getting rid of a lot of heat.
I'd grab an AC pump (cheaper than the same flow/pressure of DC/computer pumps, I think), some adapters to go from radiator hose size to copper tube size, and a copper radiator for a truck of some sort.

Numbers wise, automotive radiators need to be able to get rid of heat roughly equal to the horsepower produced by the engine. My 104hp civic generates ~77,000w of heat at full blast.

I did some testing with an aluminum radiator nissan truck radiator, it and a single 120mm fan kept a loop cooling my ~140w TEC 2.5°c above ambient. With a box fan taped to it the difference between ambient air and the water temp was <1°c.

 

[Meathead]

Automotive radiator. Cheap, massive, capable of getting rid of a lot of heat.
I'd grab an AC pump (cheaper than the same flow/pressure of DC/computer pumps, I think), some adapters to go from radiator hose size to copper tube size, and a copper radiator for a truck of some sort.

Numbers wise, automotive radiators need to be able to get rid of heat roughly equal to the horsepower produced by the engine. My 104hp civic generates ~77,000w of heat at full blast.

I did some testing with an aluminum radiator nissan truck radiator, it and a single 120mm fan kept a loop cooling my ~140w TEC 2.5°c above ambient. With a box fan taped to it the difference between ambient air and the water temp was <1°c.

Interesting thanks for the input. You are pretty much saying what I was thinking was the case.

I was looking into the AC pumps earlier but the only draw back is they are bulky for the most part. I thought it would be nice if I could mount everything inside a small case and look professionally built. I'll keep looking though.

 

[Witchdoctor]

This one may work

http://www.supplyhouse.com/Taco-003-ST4-003-Stainless-Steel-Circulator-1-40-HP-15059000-p

here is the curve data

http://s3.supplyhouse.com/manuals/1348756078398/81398_PROD_FILE.pdf

 

[Meathead]

This one may work

http://www.supplyhouse.com/Taco-003-ST4-003-Stainless-Steel-Circulator-1-40-HP-15059000-p

here is the curve data

http://s3.supplyhouse.com/manuals/1348756078398/81398_PROD_FILE.pdf

I like that pump. Do you think the maximum head of 4.5ft is going to be enough? That seems somewhat on the low side. I'm wondering if I need to run 2 separate loops to cover all 8 of the blocks. Each block will have a 90 turn coming and going from it.

 

[Ben333]

I did some testing with an aluminum radiator nissan truck radiator, it and a single 120mm fan kept a loop cooling my ~140w TEC 2.5°c above ambient. With a box fan taped to it the difference between ambient air and the water temp was <1°c.

What kind of pump did you use, one intended for PC loops, or aquariums?

And never thought about it, but that makes a lot of sense... shrouding a smaller section of a radiator to a small fan will at least do better than if the radiator was only the size of the fan.

And also, I'd recommend making your own water blocks / cooling plates, if you can do it on a budget. You can buy copper bar stock on ebay, I once ordered about a foot of 2" x 1/2". Wasn't a ton, and I was able to make a northbridge block, mosfet blocks and other stuff later on. Maybe too big of a PITA, but would be easy with a drill press & tap set.

And...

I like that pump. Do you think the maximum head of 4.5ft is going to be enough? That seems somewhat on the low side. I'm wondering if I need to run 2 separate loops to cover all 8 of the blocks. Each block will have a 90 turn coming and going from it.

Performance Data
Flow Range: 0-7 GPM
Head Range: 0-4.5 Feet
Minimum Fluid Temperature: 40 degrees F (4 degrees C)
Maximum Fluid Temperature: 220 degrees F (104 degrees C)
Maximum Working Pressure: 125 PSI
Connection Sizes: 3/4" NPT

A normal PC pump is half the price, and many times better. A circulation pump could do it too, but not that one. Not ideal anyway. A high grade aquarium pump may be ideal, if you need that much flow / pressure.

Like this --> https://www.eheim.com/en_GB/products/technology/pumps/universal-2400

http://www.swiftech.com/mcp655.aspx#tab3

Nominal Voltage 12 V DC
Operating Voltage 8 to 24 V DC
Nominal Power (@ 12 V) 24 W
Nominal Current (@ 12 V) 2 Amps
Motor Type Electronically Commutated DC Spherical Brushless Motor , with automatic overload protection and low in-rush current
Nominal Head (@12v) ~ 13 ft (4 m)
Nominal Discharge (@12v) ~ 317 GPH (1200 LPH)
Connection Size 1/2" barbs (10mm)
Maximum (working) Pressure 50 PSI (3.5 BAR)
Temperature Range 32 °F to 140 °F (0 °C to 60 °C)
Electrical Connector Molex 4-pin
Weight 1.4 LB (650 g)
Impeller material Noryl

EDIT, actually the swiftech apparently makes more head than the more expensive eheim 2400.

 

[Witchdoctor]

I like that pump. Do you think the maximum head of 4.5ft is going to be enough? That seems somewhat on the low side. I'm wondering if I need to run 2 separate loops to cover all 8 of the blocks. Each block will have a 90 turn coming and going from it.

The Taco's are very reliable pumps. I use them everyday. they make a range of stainless pumps 003 is the smallest, I thought 4' of lift would be suficient ?

 

[Ben333]

I'd not say it isn't enough, since I haven't tried. However, more flow is = better performance. Water doesn't need to "sit" to transfer heat, even with a big radiator, so more flow is a good thing. Also, lower power consumption is less heat from the pump, and I'd just assume the DC pump has the lower heat dump.

 

[Bobnova]

I used a MagDrive, I think it was a 950, ~10' of head.
4' of head isn't very much, I think you'd want more than that for 8 of those blocks in serial.

 

[RnRollie]

for a nice boxy look : use a MO-RA or Phobya (or something automotive)
http://www.performance-pcs.com/cata...t_info&cPath=59_457_667_913&products_id=37858

And an Iwaki RD-30 might fill all your needs
http://www.performance-pcs.com/cata...e=product_info&cPath=59_201&products_id=26144

Now, if you're into automotive, a couple of FUEL pumps in series might work also


Of course, all the other suggestions above are also valid... but you'll need a pump with *some* head and 4 feet isn't going to cut it

I'ld use the iwaki, put a 1/2" splitter at the discharge side, then on each leg of that Y another 1/2 to 3/8 splitter reducer.. so you end up with 4 parallel lanes/loops, once through the cold plates you return to a common reservoir. Should be able to fit all of this into a 50x40x40cm box looking VERY much like the WL2000 (with a carry handle & wheels)

 

[Bobnova]

This is the sort of thing I'd use, ebay link. Not my ebay auction, never bought from them, etc.

Fuel pumps might work for water pumps, I'd be careful about that though as most fuel injection pumps run the fuel through the motor windings and over the brushes for cooling and lubrication.

 

[Ben333]

http://www.overclockers.com/fuel-pump-water-pump/ Disadvantages. I forgot about Iwaki, those are great pumps, as said above

Damn, what a deal... http://www.ebay.com/itm/350758443702

$42.05 with free shipping, and it's brand new. Roughly 12" x 12"... I'm buying one... and I didn't even need one! lol Plastic tanks, but they don't leak on cars that operate at -20 F to 200 F so I think it ought to be alright. Planning a passive setup for my desktop

 

[PhIlLy ChEeSe]

Use a regular sump pump

 

[RnRollie]

http://www.overclockers.com/fuel-pump-water-pump/ Disadvantages. I forgot about Iwaki, those are great pumps, as said above

Damn, what a deal... http://www.ebay.com/itm/350758443702

$42.05 with free shipping, and it's brand new. Roughly 12" x 12"... I'm buying one... and I didn't even need one! lol Plastic tanks, but they don't leak on cars that operate at -20 F to 200 F so I think it ought to be alright. Planning a passive setup for my desktop

ooh, nice find

 

[Ben333]

Roughly 320mm x 320mm, ie, three 320 x 120 rads Which are usually... $60 bucks a piece at minimum, right? Plus shipping. So even if this thing isn't spectacular, me thinks it'll be a good bang for the buck.

 

[Meathead]

So I decided to just give the swiftech pumps a go at it. The max pressure that these pumps put out corresponds to the max pressure rating of most cooling blocks. I've been up and down the specs and I cannot fathom how I would benefit from going to an industrial pump. This also allows me access to any fittings that are currently made for watercooling setups so it will eliminate potential headaches down the road.

One issue I ran into is being able to use this system with the specified waterblocks : http://www.aavid.com/sites/default/...pdf/liquid-cold-plate-datasheet-hicontact.pdf

I need a way to go from 3/8" plastic tubing to 3/8" copper piping without leaking or get one of the popular waterblock companies to see if they will make a basic block with G1/4 threads so I can use whatever fitting I want. I need to be able to do 3/8 plastic tubing and then switch to copper piping once a test bench frame is finalized with blocks mounted.

If anyone else can make a block contact me. If you can do under 100 bucks a block and have them not leak everywhere, I need 4 right off the bat and possibly more down the road. I need blocks that can be sandwiched in between 2 copper plates which are attached to the transistors. I have pictures attached just pm me if you know you are capable and we can discuss specifics. I don't have any access to metal machinery so I can't do it myself.

 

[Bobnova]

How much heat is one bank of transistors going to put out? Going from the first post saying 1800w and 16 rows that would imply 112.5w/bank or 1800w/bank. I'm assuming it's 112.5w/bank for the moment, as the other option would be 360w/transistor and I'm not aware of any in that package that can deal with that much.

Are the banks going to be back to back like in the second picture when you're actually using them?

Lastly, what's your budget? I have a couple ideas on blocks.

You could always just flare the copper tube and use hose clamps.
http://www.harborfreight.com/double-tube-flaring-tool-kit-66534.html

 

[Meathead]

How much heat is one bank of transistors going to put out? Going from the first post saying 1800w and 16 rows that would imply 112.5w/bank or 1800w/bank. I'm assuming it's 112.5w/bank for the moment, as the other option would be 360w/transistor and I'm not aware of any in that package that can deal with that much.

Are the banks going to be back to back like in the second picture when you're actually using them?

Lastly, what's your budget? I have a couple ideas on blocks.

You could always just flare the copper tube and use hose clamps.
http://www.harborfreight.com/double-tube-flaring-tool-kit-66534.html

When running at full output, there will be 16 rows with a combined total output of 1.8kW from all 16 row so your assumption is correct. Yes, all of the rows will be back to back with 15.2mm gap as shown in the picture. The boards were designed with the coldplates linked in previous posts with that width. The copper strips are 12cm long and I planned on drilling mounting holes at 1cm and 11cm midlevel.

Budget is there is no way around this. It needs to be done. I should be more clear in that I will need 8 of them total. The current coldplates are $110 a piece with 8 total approx $900 is what is currently being proposed. Not sure about the ceiling. Whatever doesn't get approved.

 

[Bobnova]

I've found places that make square copper tube with a round hole bored through the middle. If you can find that stuff in the proper size it would probably work pretty nicely. The ends could be threaded for fittings, and you're set.

I think I'd try flaring the pipe on the blocks you already have first though. That's cheap and may be quite effective.

What is this thing you're cooling, anyway?

 

[tungureanu]

i`m guessing some kind of ultra powerfull next-gen cheap-ish ASIC.