Water cooled led system

[kenneth wolfe]

Hello fellow reefers.. I am in the process of a new build I like to try and be as natural as possible ..My thoughts on a led multichip high wattage cooling system .I thought with the cost of having to light and heat the system can be quit high and also ugly with the large heat sinks and noisy fans led me to re think the system ...hmm..Why not use a stainless steal heat exchanger and a high temp. refuge aka dsb ect. ect. My thought is with the remote high temp. you use that to stabilize the large dst and have a larger biodiversity with the remote high temp. growing things that don't grow at 78 degree F. So in theory the remote heater /"what ever" is "set at the "working temp" lets say 100 degree f." of the fixture and its full of goodies and when the display needs heat you pump from it.. This is an idea that I am running threw my head ...I like to put multiple functions into things I take the time to build..I see a slim fixture being water cooled ....total water volume =1000g ,500 gdt With all that being said any thoughts on my idea good bad what ever..I have good fabrication skills with access to good tools..he he he ..

 

[gbru316]

1. If you're planning on running saltwater through the heat exchanger, I'd think twice. Stainless will corrode in saltwater. Titanium would be your best bet, but it's not cheap.

2. Using your light fixture to heat water is going to be problematic at night. You're still going to need heaters.

3. LED fixtures don't need active cooling if heat sink has enough surface area. This does NOT mean they need to be large. I have 36 emitters on a passively cooled 8x12x1 heat sink and it doesn't get any hotter than 90 degrees. LEDs are also more efficient when running them at less than 100%.

4. You'll most likely have difficulty changing the temperature of that volume of water with the method you describe. See #3

5. What happens when the tank doesn't need heat but the LED's need cooled? Periodic active cooling of the LED fixture is going to be difficult to implement if it's directly tied to the aquarium temperature. You'd need a heat exchanger that can cool the fixture without water being pumped through it, or you'd need a valve to switch the cooling water from a separate, fan cooled heat sink (when the tank doesn't need heat) to a heat exchanger for tank water.


From an engineering standpoint, I find that following the KISS principle is often one of the best strategies. With the method you describe, you have multiple critical system components relying on 1 subcomponent. If the heat exchanger pump dies, you lose heat and light. If the lights fail, you lose heat. The setup you describe has a reliability issue that could be easily mitigated by keeping the heating and lighting separate. Although it sounds like a cool idea, my professional experience says don't do it.

 

[asudavew]

+ We usually try to keep the heat from our lights out our tanks. Not in.

 

[mcgyvr]

yeah... bad idea..

 

[marspeed]

I think it is a good idea

 

[karimwassef]

Liquid cooling works, but salt water is a poor choice. Use a fresh water loop with an evaporator.

 

[gbru316]

Liquid cooling works

Yes. However, you might still need a radiator (with fan) to cool the heated water down before it travels through the water block that the emitters are fastened to. Depends on cooling system volume. As the water heats up, the cooling capacity decreases.

Although, with the heat levels produced by LEDs (minimal, comparatively), I'm not sure something like this requires this much work. A plain aluminum heat sink (note, an actual finned heat sink) with some thermal grease accomplishes the job with much less effort, and you don't have to worry about leaks or pump malfunctions.

 

[Indymann99]

+ We usually try to keep the heat from our lights out our tanks. Not in.

The OP lives in Colorado... I bet 5mo out of the year he would benefit from heat from the lights going INTO the tank... Prob not much of an issue for you in TX...

That said I would think the complexity and potential for leaks would outweigh the benefits of liquid cooling LEDs

 

[sfsuphysics]

if your fans are noisy you are using the wrong fans and/or running them way too fast.

 

[kenneth wolfe]

a couple of things to consider..I am in the protective coatings business ( High grade stainless and a good coating should not fail) , when I say high wattage I meen say 1500 watts or more . the remote fuge will be large over 150 gallon ..its not a cure for not needing a heater but with that amount of reserve it should hold over night ...I also feel the high temp in the fuge is a great bonus to the system..how many fans and heatsinks do you imagine for 1500 w. that's a large noisy fixture..I see a fixture no more than an inch thick total..stainless steel exchanger inside a aluminum housing ..my water cooled welding rig is 250amp and cools with 1/8" inch feed and return lines.

 

[gbru316]

Sounds like your mind is made up. Have fun, take pics.

 

[kenneth wolfe]

no no ..not at all ..just trying to find some alterative thought..the titanium would be nice but not in my budget..if we are talking about 1500 watts that's not a lot of heat to process for a system that large . and the rooms are air conditioned .so its possible that just running in to the system would be fine..(the system has a chiller)I like the closed loop idea also ..my remote cooler for my welder would do the job for less money than a large heat sink and fans..not its hard to find large heatsinks cheaply with out welding them together or some extra fab work.vrs welding a heat exchanger.I have been threw most of the led build on here and haven't seen many water cooled threads ..its also a lot to do with the ability to have a hot bed for bio culture that's not present in a " cooler environment " the reword might be worth more than the risk ...

 

[karimwassef]

I run 200W on a 4" wide Aluminum finned strip (8ft long). I use small quiet 3" fans.

I can probably double the wattage and still have margin.

With 4x the Aluminum surface area, you can do 1600W.

<a href="http://s1062.photobucket.com/user/karimwassef/media/4AE21775-3C3E-4F8E-89EA-72051279323F_zpsyl6vd2nu.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/4AE21775-3C3E-4F8E-89EA-72051279323F_zpsyl6vd2nu.jpg" border="0" alt=" photo 4AE21775-3C3E-4F8E-89EA-72051279323F_zpsyl6vd2nu.jpg"/></a>

 

[karimwassef]

<a href="http://s1062.photobucket.com/user/karimwassef/media/AA01D0DB-9EE2-4117-8803-1766CFCA9D94_zpsja6sjenk.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/AA01D0DB-9EE2-4117-8803-1766CFCA9D94_zpsja6sjenk.jpg" border="0" alt=" photo AA01D0DB-9EE2-4117-8803-1766CFCA9D94_zpsja6sjenk.jpg"/></a>

 

[kenneth wolfe]

What temp. does that fixture run at if you don't mind Im trying to get an area to wattage formula ..yours is 384 sq. inch/200 1.92 per watt ..sound wright ??

 

[kenneth wolfe]

I follow your thread on the rock wall...wish you live closer..not that many close to me here..

 

[karimwassef]

Thanks. 200W/384in2 ~ 0.52W/in2 but I think you can double it.

I don't think it runs higher than 40C. I can touch it and it's warm but not hot.

 

[kenneth wolfe]

is your math backwards or mine..lol... 0.52 is small do you think??

 

[karimwassef]

I measure W/in2. You're measuring in2/W. We're saying the same thing.

 

[kenneth wolfe]

I see that now after I read it again..lol..My opening is 35" x15" for lighting a 48" x 72" round tank. My thought was with the roughly 475 in2 ..Im going to have to fill it to the max.. lets say 1500w/475 in2 is.. lets say 3 w in2 ...and possibly more maybe 2500 watts for 5/w gallon ..the depth of the tank is my concern ..I know I can put optics on the drivers ..if I need more penetration but I don't like the "cone effect" and with the fixture being so close to the water I need the spread..