Water cooled cob setup?

My first post! I am more of a listener than a talker usually, but figured I would see if anyone else has built a water cooled cob setup. Unfortunately, my girls are sleeping right now so I cannot get a pic to show it off, but I did in fact build such a light using items on hand and some from Lowe's. The reasons I figure this is a good idea is to remove heat from the grow area completely, and is cheaper than buying numerous heatsinks. I live in an extremely hot and dry area plus my grow setup is in my garage, so heat is my biggest enemy right now.

So here goes: For the "heatsink" I used ~28" x 2" x 1/8" aluminum strap that the cobs are screwed to. On top of that I have ~30"(sorry I don't remember the exact lengths) x 3/4" aluminum square tubing which I have water flowing through. The aluminum strap and square tubing were both wet sanded to 600 grit, then I applied Artic silver thermal compound above the cob locations and a thin bit of epoxy in the other areas and used about 10 clamps holding the pieces together while the epoxy cured. Picture the square tubing epoxied on top of the strap and extending about an inch on either end. Wow this is hard to explain without pics!

Once the strap and square tubing epoxy cured, I had to figure a way to attach some 90* barb fittings to the ends of the square tubing. So what I had on hand was some adhesive lined heatshrink tubing I used for making battery cables and I just heatshrunk (my patented new word) the 90 degree barb fitting onto the ends. I made 2 of these strap/square tubing sets for now with 1 cob on each end of each of the 2 setups for a total of 4 cobs, but plan to add another in the middle of each setup for a total of 6.

So each strap setup is plumbed in parallel (not series) using 1/2" vinyl tubing from Lowe's with the inlet side connected to a fountain pump that I stuck into a 1 or 2 gallon bucket and the outlet also dumping into the bucket. As a trial run for a couple days while I tried to figure out a cheap radiator setup I just ran the LEDs with the water and pump. The water temps were approx 110* F during the hottest times of the day. I never really found a fire sale on any radiator/heat exchanger so I did some other home grown ingenuity and just plumbed in another 20" of vinyl fountain tubing and spread it out under my grow cabinet on the cooler concrete floor. Now my water temps stay a bit below 100* and the 2' x 3' grow cabinet is staying cooler.

I'm sure I did not explain that well enough, so just ask if you have any questions about it. I will get some pics tomorrow and figure out how to post them here.

Here's a pic of my water cooled COB LED fixture;


I used a water chiller to actively cool the water, which dropped the temperature of the chips into the mid 60s!

You should consider running the water for your lights in series, this scours the heat better.

Consider using a junkyard car radiator with a fan to extract heat by pulling air through it. Don't push the air!

If/when I get a radiator of some sort, I may put it directly in front of my swamp cooler to really cool it. If that is not cool enough, I have a refrigerator in there I could put a coil of tubing into. But honestly, so far they are working as I wanted. I still have the LED driver in the grow cabinet, but can relocate that as well if I need to remove more heat.

Big Green Thumb said:

If/when I get a radiator of some sort, I may put it directly in front of my swamp cooler to really cool it. If that is not cool enough, I have a refrigerator in there I could put a coil of tubing into. But honestly, so far they are working as I wanted. I still have the LED driver in the grow cabinet, but can relocate that as well if I need to remove more heat.

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Pull air through it, don't push. You could also submerge it in a body of water, and evaporation will help cool things.

Big Green Thumb said:

so far they are working as I wanted.

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No matter how cool the are running now, they will run better at a lower temperature. If the refrigerator is convenient and already powered on, then by all means use it. You could lower the electricity usage by 10%.

You don't need a coil if you put your water reservoir in the fridge. If you do use a coil submerse the coil in water for better convection.

You may want to consider using two pumps so when one fails the other will save your ass. The pump will fail, it's a matter of when not if.

NoFucks2Give said:

You don't need a coil if you put your water reservoir in the fridge. If you do use a coil submerse the coil in water for better convection.

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I looked into doing this with a bitcoin mining rig (liquid cooled GPUs instead of cobs, with the res in a freezer) and the problem was that the consumer fridge or freezer compressors are not made for constant run witch is required as you are pumping heat into the chamber at a constant rate over many hours. Upgrading your compressor with a constant run model (commercial compressor not consumer grade) solves the issue of killing compressors. So I have been told.

Have you tried this, if so any issues?

canadian1969 said:

Have you tried this, if so any issues?

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You were told correctly. Depends on the type of freon. The older R-12 is much better. It also depends on the amount of heat. If you are trying to displace more BTUs then the refrigerator is rated for, it will be a problem. I have not tried using a refrigerator as it adds too much to system inefficiency. I am looking into using a small 26 lbs. per day ice maker. But I would rather have a sealed system for better microbial control.

This is why ppl like @ttystikk and others use chillers. They are designed for constant usage and are highly more efficient than a refrigerator or freezer. You'll save a lot of time and money just buying a chiller than dicking around with all these DYI solutions. I learned my lesson. In addition, the chiller allows you to dial in the temperature of choice by its simple control panel. It's worth investigating. My 2 cents.

Organic Miner said:

This is why ppl like @ttystikk and others use chillers. They are designed for constant usage and are highly more efficient than a refrigerator or freezer. You'll save a lot of time and money just buying a chiller than dicking around with all these DYI solutions. I learned my lesson. In addition, the chiller allows you to dial in the temperature of choice by its simple control panel. It's worth investigating. My 2 cents.

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cool., this is new to me,. can you give me an example?

NoFucks2Give said:

No matter how cool the are running now, they will run better at a lower temperature. If the refrigerator is convenient and already powered on, then by all means use it. You could lower the electricity usage by 10%.

You don't need a coil if you put your water reservoir in the fridge. If you do use a coil submerse the coil in water for better convection.

You may want to consider using two pumps so when one fails the other will save your ass. The pump will fail, it's a matter of when not if.

Click to expand...

Refrigerator does not have the capacity to handle the ongoing heat load.

Use a thermal switch so if things get hot, the light shuts down.

Thermal droop does not offset the energy used to cool the lights, although reduced HVAC does.

NoFucks2Give said:

You were told correctly. Depends on the type of freon. The older R-12 is much better. It also depends on the amount of heat. If you are trying to displace more BTUs then the refrigerator is rated for, it will be a problem. I have not tried using a refrigerator as it adds too much to system inefficiency. I am looking into using a small 26 lbs. per day ice maker. But I would rather have a sealed system for better microbial control.

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Type of refrigerant is not important. Chiller system capacity is.

canadian1969 said:

cool., this is new to me,. can you give me an example?

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ChillKing

Surna sucks.

If you really want to DIY, Loki_grow on IG made a DIY chiller for his DWC system. Might be able to get some inspiration there.

@ttystikk goes for the industrial size chillers for his production, if you want to get your feet wet you can buy a Active Aqua Chiller off Amazon. I have both the 1/2 and 1/4 HP. Use them for resivour cooling, not light, but they are awesome. Keeps my 250 gal RDWC flower system at 68 degrees. Just a thought.

If I ever get the opportunity to rebuild my setup bigger, I will go with the ChillKing .... baby steps.

Organic Miner said:

@ttystikk goes for the industrial size chillers for his production, if you want to get your feet wet you can buy a Active Aqua Chiller off Amazon. I have both the 1/2 and 1/4 HP. Use them for resivour cooling, not light, but they are awesome. Keeps my 250 gal RDWC flower system at 68 degrees. Just a thought.

If I ever get the opportunity to rebuild my setup bigger, I will go with the ChillKing .... baby steps.

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I was doing a lot with my chillers. The reason they were big was because I used them instead of standard AC units for environmental control. They were more efficient.

I'm thinking that active chilling of water cooled lighting is overkill.

What is a cheap, reliable water pump? I already had this fountain pump and I agree they do not last. The best pump I can think of is a hot water recirculating pump like Grundfos for example. Not cheap, but as reliable as a rock. Maybe a bilge pump?

Big Green Thumb said:

What is a cheap, reliable water pump? I already had this fountain pump and I agree they do not last. The best pump I can think of is a hot water recirculating pump like Grundfos for example. Not cheap, but as reliable as a rock. Maybe a bilge pump?

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My hydro store pumps are great as long as they stay in the water to keep cool, it's clean water and run continuously.

What water block are you using ttystikk?

aquanaut said:

What water block are you using ttystikk?

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Custom made from 2x4" square section aluminum, 3/16" wall thickness. It's structural material lol. Weird end caps with dog ears for mounting and a 1/2" hole drilled and tapped for NPT.

Heavy duty enough that I can fill it with water and it will not overheat, even with no water circulation, as long as there's some airflow.