Water cooled COBs

[ttystikk]

Thanks

They're running at 33.5V and 620mA each so just over 20W.

In terms of efficiency these are supposed to be 119 lm/w (90 CRI so the PAR is probably higher than the lumens would suggest) at 37.3W and 85C. I've estimated I'm getting around 133lm/w by running them at 20W and water cooling them to a surface temp of 46C. TBH this is all theoretical and it doesn't really matter to me what extra efficiency I'm getting or could get. Why?

1. Without water cooling I'd not be able to run this many watts in such a small area in my loft. I can't get a big AC unit in my loft. So comparisons to air cooling at the same wattage are moot (for my situation).
2. I couldn't afford more efficient COBs at the moment. 250 of these Citizen chips cost me £550 delivered. If I went with 120 CXB3950s instead I'd be looking at paying at least £3200 on the grey market. The extra efficiency and power saving (probably around 10% going from 55% to 65%) would take a hell of a long time to offset that upfront cost.

My lighting energy costs £1660 per year. If I needed 15% less energy (1-(55/65)) to get the same results I'd save £249 a year... (3200-550)/249= 10.5 years for the CXBs to pay for themselves with efficiency savings over the cost of buying the Citizens.

I'd love to say I'll still be using the same setup in 10 years. Realistically that ain't gonna happen.

Edit: Just edited my power savings calc which I think was a bit off.

I think your solution is well suited for your needs and you may find yourself running those chips longer than you might think.

 

[DIY-HP-LED]

Have a look at this new posting about water cooled COBS on my thread

 

[DIY-HP-LED]

NEW WATER COOLED DESIGNS

It's been awhile since I've posted anything here, but I've been busy building lights, growing and learning. My light designs have gone through a couple of generations and I've recently completed a large air cooled light (500 actual watts) with a flow through design and ducting to remove heat. I wasn't satisfied with the result, so I dropped plans for a larger 4' long version. I'm using over 1000 watts in a regular sized room and the heat build up is too much and air cooling the LED lights wasn't working out too well. So I decided to try a radically different approach, water cooling. I think I might start a new thread on this subject since I figure it deserves more attention. I've got a couple of economical designs in the works that should prove very interesting to any DIY grow light builder.

A few days ago I made a prototype light to test a few ideas and shatter some assumptions. The ease of building, cost and efficiency, convinced me that this is the way to go for anybody who wants to put lots of LED power into a small space with no increase in heat. Your carbon filter and blower are for reducing odor, not cooling your lights, with water cooling you can reduce your blower speed to a fraction. A sealed room and CO2 enrichment is easily possible with water cooling and the only noise you'll hear is the sound of an oscillating fan.

See the link in the post above to go to my thread.

 

[fearnoevil]

Thanks

They're running at 33.5V and 620mA each so just over 20W.

In terms of efficiency these are supposed to be 119 lm/w (90 CRI so the PAR is probably higher than the lumens would suggest) at 37.3W and 85C. I've estimated I'm getting around 133lm/w by running them at 20W and water cooling them to a surface temp of 46C. TBH this is all theoretical and it doesn't really matter to me what extra efficiency I'm getting or could get. Why?

1. Without water cooling I'd not be able to run this many watts in such a small area in my loft. I can't get a big AC unit in my loft. So comparisons to air cooling at the same wattage are moot (for my situation).
2. I couldn't afford more efficient COBs at the moment. 250 of these Citizen chips cost me £550 delivered. If I went with 120 CXB3950s instead I'd be looking at paying at least £3200 on the grey market. The extra efficiency and power saving (probably around 10% going from 55% to 65%) would take a hell of a long time to offset that upfront cost.

My lighting energy costs £1660 per year. If I needed 15% less energy (1-(55/65)) to get the same results I'd save £249 a year... (3200-550)/249= 10.5 years for the CXBs to pay for themselves with efficiency savings over the cost of buying the Citizens.

I'd love to say I'll still be using the same setup in 10 years. Realistically that ain't gonna happen.

Edit: Just edited my power savings calc which I think was a bit off.

Hey Lofty, just want to say I really like your water-cooled light bar, and the radiator/fan setup it exactly as I imagine mine will be when I get done with it. I'm building a 46" prototype, using 6" x 2" aluminum tube though, with the idea of getting rid of the individual blocks and all the tubing and fittings so there are fewer potential leaks. If the prototype works, I'll be looking at building several more, vamos a ver ;?D

At the moment I'm trying to decide how to mount the COB's, but I'll be using thermal epoxy so no drilling into the body. This is my first build so not sure what to expect, but it will be interesting to say the least, lol. Here's a pic of the heat sink bar, just got it back from the welding shop ;?)

 

[loftygoals]

Hey Lofty, just want to say I really like your water-cooled light bar, and the radiator/fan setup it exactly as I imagine mine will be when I get done with it. I'm building a 46" prototype, using 6" x 2" aluminum tube though, with the idea of getting rid of the individual blocks and all the tubing and fittings so there are fewer potential leaks. If the prototype works, I'll be looking at building several more, vamos a ver ;?D

At the moment I'm trying to decide how to mount the COB's, but I'll be using thermal epoxy so no drilling into the body. This is my first build so not sure what to expect, but it will be interesting to say the least, lol. Here's a pic of the heat sink bar, just got it back from the welding shop ;?)

View attachment 3795110 View attachment 3795111 View attachment 3795112

That looks great. I've seen a few pics/posts of people doing something similar. The fewer connection the better

Let us know how it all works out!

 

[loftygoals]

1800w of water cooled COBs in a 8x4 space (have 2 identical tents flip flopping):

 

[ttystikk]

1800w of water cooled COBs in a 8x4 space (have 2 identical tents flip flopping):

View attachment 3801591

Hubba, hubba- nice lights ya got there!

 

[Unscentedcommon]

Great setup. I'm basing my build on yours and I wanted to know if you had any issues with condensation. Any idea on how cool you're running your chiller?

 

[Unscentedcommon]

Great setup. I'm basing my build on yours and I wanted to know if you had any issues with condensation. Any idea on how cool you're running your chiller?

Guess I just had to read a bit...
"COB surface temp is 46C, water temp out of the radiator 30C, water temp going in to the radiator 38C, floor temp 26C, canopy temp 30C."


Any issues/concerns with condensation? I was considering on running a chiller but was concerned about moisture forming due to the wider delta of temperatures.

 

[Shugglet]

Guess I just had to read a bit...
"COB surface temp is 46C, water temp out of the radiator 30C, water temp going in to the radiator 38C, floor temp 26C, canopy temp 30C."


Any issues/concerns with condensation? I was considering on running a chiller but was concerned about moisture forming due to the wider delta of temperatures.

Considering he doesn't actively cool the water condensation will never be an issue.

Though if you were concerned it would be determined by the dew point in the room and how adequately the water blocks are insulated

 

[ttystikk]

Guess I just had to read a bit...
"COB surface temp is 46C, water temp out of the radiator 30C, water temp going in to the radiator 38C, floor temp 26C, canopy temp 30C."


Any issues/concerns with condensation? I was considering on running a chiller but was concerned about moisture forming due to the wider delta of temperatures.

Moisture will only form on surfaces below the room's dew point.

 

[loftygoals]

That's right; I have no condensation issues as I only have a fan cooled radiator.

 

[Olive Drab Green]

Moisture will only form on surfaces below the room's dew point.

Maybe I'm just paranoid, but I just have reservations regarding combining water and electricity. We even switched from water-cooled machineguns to air-cooled ones. I'll just stick with my fans and large heat sinks. God knows I have nearly died enough, and I'd rather not survive combat for me to butterfingers my light and electrocute myself.

 

[ttystikk]

Maybe I'm just paranoid, but I just have reservations regarding combining water and electricity. We even switched from water-cooled machineguns to air-cooled ones. I'll just stick with my fans and large heat sinks. God knows I have nearly died enough, and I'd rather not survive combat for me to butterfingers my light and electrocute myself.

So what part of a machine gun is electric?

 

[Olive Drab Green]

So what part of a machine gun is electric?

Nothing, but machineguns get hotter and air cools them just fine.

 

[Shugglet]

Maybe I'm just paranoid, but I just have reservations regarding combining water and electricity. We even switched from water-cooled machineguns to air-cooled ones. I'll just stick with my fans and large heat sinks. God knows I have nearly died enough, and I'd rather not survive combat for me to butterfingers my light and electrocute myself.

Air cooling is just as effective as water cooling, each just have their strengths and weaknesses.

The whole water and electronics thing always makes me laugh though. Computers have been water cooled for decades...

Youre light should never be powered any time you are working on it... It really is that simple. Anyone who does that deserves the darwin award. (knocks on wood). lol

 

[Olive Drab Green]

Air cooling is just as effective as water cooling, each just have their strengths and weaknesses.

The whole water and electronics thing always makes me laugh though. Computers have been water cooled for decades...

Youre light should never be powered any time you are working on it... It really is that simple. Anyone who does that deserves the darwin award. (knocks on wood). lol

I was only speaking personal preference, not general standard, bro.

 

[Shugglet]

I was only speaking personal preference, not general standard, bro.

I was more speaking to the paranoia. Your personal preference is often the number one stated concern when discussing this topic.

"butterfingers" can kill you working with electricity regardless of whether or not water is involved, when you dont take the necessary precautions.

 

[Olive Drab Green]

I was more speaking to the paranoia. Your personal preference is often the number one stated concern when discussing this topic.

"butterfingers" can kill you working with electricity regardless of whether or not water is involved, when you dont take the necessary precautions.

You're taking this too seriously.

And, I'd rather just eliminate the potential extra hazards and make this easier.

 

[wietefras]

Say it's leaking water . What would/could happen?