Liquid Cooled 8 COB Cabinet

Sxott

Sxott

Well-Known Member
I have been reading threads here on COBs for days on end until my brain hurts. Im very thankful to all the knowledgeable people that have been putting out all this good info along with the people sharing their experience. Im very eager to get rid of my HPS heaters.

Here is what I have in the works:

I a 48"Lx24"Dx42"H cabinets a while back for scrogging with LEDs.

I plan on using 8x cxb3070 cobs and 2 HLG-185H-C1400b (thanks to apoulin thread) 4 in series.

For a heatsink 2x 36" pieces of square or rectangular aluminum stock (little wider than chip board). I am a welder so I can tig weld barbed fittings onto these and connect them with another piece of stock to form a U shape. A cheap Hayden transmission cooler with an inline pump will be located outside the cabinet to water cool these tubes. The drivers will also be mounted outside the cabinet. In the event of the coolers fan or pump failing,there will be a thermo switch with probe attached to the heatsink to kill the power before the cobs burn.

This set up will allow me to mount all 8 cobs within an inch or 2 from the top of the cabinet.

Here are some issues I am thinking about:

1) I cant drill into the heatsink tubing because its full of liquid. I dont want to use adhesive because I dont want to ruin the chips in case I want to swap them out for some 5000Ks for vegging. Can these molex holders be attached with adhesive and thermo paste on just the chip part?

2) How hot do these really get? Its hard to grasp it reading it online. Will 8 cobs at 1.4 be too much radiant heat at say 10" from the plants? Is the transmission cooler mounted outside an overkill or could I just get away with mounting a couple CPU water cooler radiators in front of my exhaust fans leaving the cabinet instead. (2x SP120 high static pressure PC fans)?

At about 50 watts a cob, That will add up to about 400 watts in the cabinet. If this cabinet works, I will be stacking a second one on top of it. (i have 2) Its the reason I bought 42" high cabinets. It would be nice to out produce my 1000 watt hps in a 2x4 floorspace using 20% less power :) and hopefully no AC too. Plus have all my babies on different schedules in the same room.

I will open up a paint program and try to illustrate everything Im talking about here real soon.
 
Mechmike

Mechmike

Well-Known Member
Your idea should work great. It will probably never get over 40c. I haven't done it myself but I have pondered how to attach emitters to a water block so they can be replaced without damaging anything. I was thinking that 2" lengths of 2" x .25" aluminum flat strap bonded to the water block with Arctic Silver thermal epoxy to mount your emitters on. The thermal epoxy transfers heat very well and with .25" of "meat" and some careful drilling you can use short screws to mount the emitters without breaching the wall of your water block.

You could also drill and tap the short pieces of flat strap before bonding them to the block to avoid the possibility of drilling into the water block. The threads would have to be cleaned out after the epoxy sets unless 1/4" screws are threaded all the way into the holes to keep the threads clean.
 
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Rahz

Rahz

Well-Known Member
Sxott said:
2) How hot do these really get? Its hard to grasp it reading it online. Will 8 cobs at 1.4 be too much radiant heat at say 10" from the plants? Is the transmission cooler mounted outside an overkill or could I just get away with mounting a couple CPU water cooler radiators in front of my exhaust fans leaving the cabinet instead. (2x SP120 high static pressure PC fans)?
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It seems it's not heat but an excess of light that causes bleaching. I was reading a thread on another forum in which a person had heavily bleached plants and was doing it on purpose. Other than the color they looked healthy and according to the poster quality didn't suffer, so apparently bleaching tops isn't necessarily hurting the plants.

With enough wattage a cob could probably put off enough heat to harm plants, but I'm not sure on specifics. I have 25 and 30 watt units, both cause no bleaching as close as 6" so I'm going to guess 50 watts at 10" would be fine.
 
Sxott

Sxott

Well-Known Member
Mechmike said:
Your idea should work great. It will probably never get over 40c. I haven't done it myself but I have pondered how to attach emitters to a water block so they can be replaced without damaging anything. I was thinking that 2" lengths of 2" x .25" aluminum flat strap bonded to the water block with Arctic Silver thermal epoxy to mount your emitters on. The thermal epoxy transfers heat very well and with .25" of "meat" and some careful drilling you can use short screws to mount the emitters without breaching the wall of your water block.
Click to expand...
Great idea. Then that will be the plan. I was thinking the same thing except drilling and tapping the holes on the .25" flat bar first and welding it to the the block with thermo paste between but feared it would slow down the heat transfer too much and distort the parts. Using epoxy for it would work great. Ill just cover the whole 36" piece with the predrilled flat bar. Thanks for chiming in.

sidecob.jpg

Mineral oil is a great idea too in case a leak would develop

You think the two small radiaters on the exhaust would work? I can eliminate the big fan thats way.
 
Sxott

Sxott

Well-Known Member
Too much light and not enough heat is a is prob I would love to have :) I calculated that the lumen output would be close to what half of my 1000 watter hps is putting out. But then again that is at 18" from plants in the center. If 1.4 turns out to be too much. I will swap the drivers out with 1 ampers.
 
Mechmike

Mechmike

Well-Known Member
Sxott said:
Great idea. Then that will be the plan. I was thinking the same thing except drilling and tapping the holes on the .25" flat bar first and welding it to the the block with thermo paste between but feared it would slow down the heat transfer too much and distort the parts. Using epoxy for it would work great. Ill just cover the whole 36" piece with the predrilled flat bar. Thanks for chiming in.

View attachment 3372177

Mineral oil is a great idea too in case a leak would develop

You think the two small radiaters on the exhaust would work? I can eliminate the big fan thats way.
Click to expand...
That should work fine. I would use the pc fans, get and wire in a temperature controller to run the fans only as needed to keep the coolant temperature low. The exhaust fan may work but dedicated cooling is better. Temp controller like this http://www.amazon.com/Lerway-All-Purpose-Temperature-Controller-Thermostat/dp/B008KVCPH2/ref=sr_1_1?ie=UTF8&qid=1426394009&sr=8-1&keywords=temperature+controller
 
Sxott

Sxott

Well-Known Member
Mechmike said:
That should work fine. I would use the pc fans, get and wire in a temperature controller to run the fans only as needed to keep the coolant temperature low. The exhaust fan may work but dedicated cooling is better. Temp controller like this http://www.amazon.com/Lerway-All-Purpose-Temperature-Controller-Thermostat/dp/B008KVCPH2/ref=sr_1_1?ie=UTF8&qid=1426394009&sr=8-1&keywords=temperature controller
Click to expand...
Already have one built :) I use it to keep my vacuum purge unit at solid temp using water and a hotplate. I even have an extra in the box still.

image (2).jpegimage (4).jpeg
 
Sxott

Sxott

Well-Known Member
Scotch089 said:
Super cool idea. I wish someone would make a how to thread on those temp controllers like what positivity/stardustsailor has got going on.
Click to expand...
I have not seen his thread yet. If you type "stc-1000" in a YouTube search, a ton of videos on how to wire it pops up. You can always change it to power a AC device instead of an outlet. There are also dc temperature switches out there in case you want to wire a 12v fan right to it.

Scotch089 said:
Super cool idea. I wish someone would make a how to thread on those temp controllers like what positivity/stardustsailor has got going on.
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Thank you for the info. It would only matter if it were to leak somehow. Thats highly unlikely. 10x? Sounds like water and antifreeze for the win,
 
Positivity

Positivity

Well-Known Member
Scotch089 said:
Super cool idea. I wish someone would make a how to thread on those temp controllers like what positivity/stardustsailor has got going on.
Click to expand...

I can put something together when i have some time. I haven't done it yet because of the amount of wires it adds to builds.

The jist is...
5v to power the screen. Needs a dedicated 5v source
12v to the fans
Temp sensors to the cobs

And it only really helps when running cobs hard and testing different cooling options. Otherwise, its a lot of work to see that your cobs are running only a few degrees above ambient
 
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apoulin

apoulin

Well-Known Member
WELLL HELLLOOO! My ears were burning, I knew someone was talking about me :cool:

I am excited to see this, I thought about doing something similar but with a spare CPU watercooling system I had. Figured I could use the adhesive the same way I did on the heatsinks, but have all of the plumbing and cooling system figured out. I had that cooling system filled with mineral oil.

bongsmilie:clap:

Maybe after you give it a go, I will do a smaller modular design with CPU water coolers w/mineral oil :leaf::peace::mrgreen:
 
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