LED Build for 400g Tank

[nreefer]

Hi all, after many months of reading I am ready to start my LED build.
Some background:
I have a 400g reef tank (96 x 30 x 32) with SPS, Clams, LPS.
The tank designed as a penninsula room divider viewable from 3 sides (both long sides and the front)

My current lighting is 4 x 250w DE Ushio 14K bulbs with T5 Actinic supliment.

I am going to build a 224 LED fixture made up of 80 XP-G CW and 144 XP-E RB leds driven off 4 Meanwell HLG-240-48 drivers running parallel strings.
I'll be using resistors and quick blow fuses to ensure I protect the led's in case of failure of one led.

Fixture will be 10 to 12 inches off the water

I'll make an 1/4" acrylic splash shield

Made from 8 U-Channel aluminum pieces

Total fixture size is 16" wide, 84" long. (Because I have eurobracing that limits my open water on the tank to 18" x 84" and there is no point in having LED's blasting down onto the Eurobracing)

Combination of 40 deg. and 65 deg. optics. The 40 deg. optics will be used on the edges of the fixture to penetrate the light deep onto the sand bed and I'll use the 65 deg. optics as I get closer to the center of the tank.

I am using the thermal paste and screw down method of attaching the LEDs (so I can mode the fixture in the future and also adjust the forward voltage to balance the strings easier)

I have built the Aluminum fixture and now I am deciding on mounting the fans.
Should I go with option #1: all fans in a row down the center
of option #2: fans together each cooling a third of the fixture.

<a href="https://picasaweb.google.com/lh/photo/q5FOUKDfvEYk2RB-iuJ-80GwvVygLUjeaAK_hyYqfGU?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/_jiSQPR-FAUI/TVgIv-4hgbI/AAAAAAAAEV8/GpwDTGdKHVQ/s400/DSC07027.JPG" height="400" width="300" /></a>

Option #2 is easier for layout reasons (fans can be simply drilled into the U Channels without making any cross members)

<a href="https://picasaweb.google.com/lh/photo/bux16x58k1YehktL4fqkK0GwvVygLUjeaAK_hyYqfGU?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/_jiSQPR-FAUI/TVgIv520hyI/AAAAAAAAEWA/sZYFFxAMRqU/s400/DSC07026.JPG" height="400" width="300" /></a>

any thoughts? or does it really matter?

 

[BluScrnOdeth]

Are you going to have these enclosed? With the width of your fixture i would prob do option 2 as long as they stand off about 4-6 inches. You should have some breeze touching all the rails. Those look like 120mm Fans correct? If they are completely enclosed they could create enough wind in there to properly cool without directly blowing over them.

However, i feel that option 2 is the best considering the width of your design. Though, i have a smaller rail system just like that at home i'm testing with convection heating today. I had it running for a couple hours last night and it got warm but nothing more than a typical heatsink warm (can touch without discomfort).

Though i think that if you could find a way to line them up on the back side to blow across them (option 1) would be your best bet.

 

[nreefer]

thanks for the reply, I don't have the space to have the fans mounted 4-6 inches above the fixture. You are correct, these are 120mm fans. the fixture won't be totally enclosed but the splash shield should direct the air somewhat uniformly around all the U-channels.

 

[110galreef]

awesome build! .....personally for that many LED's and the cheap cost of fans, I'd atleast go option 2 style, but go 3 fans per row (left to right)& also add at least one more row.


Or put like 3 rows of 3, but stand them up and blow the length of the aluminum rails toget good airflow down the rails......

Will be harder to mount, but probably better & more spread air flow. As current will probably have some led running pretty hot as the get far away from fan & probably minimal air flow.

Also how thick is the aluminum and how far apart wil the led's be apart?

 

[110galreef]

Or stager the fans so at least all rails get some air flow directly from a fan. I'd still ad maybe 3-4 fans....

Also just align them so the screw easily into each rail

 

[110galreef]

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Kind of like this...*= a fan

 

[username in use]

I agree, you have 2 u channels that won't get any direct air flow on them. I think you need to go 3 wide, and 4 rows as well. You may still run into heat issues in between the fans.

The real question that will be a factor in this however, is how many led's per u-channel and what is their spacing going to be?

 

[BluScrnOdeth]

I agree witih 110. If you could angle them down the length of the rails with 3 per row, you should be good. His other suggestion (diagram) wouldnt be half bad either. Though i still feel if you could make a couple side skirts to mount the fans in a row to blow straight across the rails would be your best solution.

But like i said, even with no fan on my setup, using just convection, the rails didnt get really hot. Though how that will effect them long term i'm not sure. My dad was telling me that water eveporation from the tank will help some (very little he said), but i think thats a long stretch. I'll prob still build an enclosure for mine and put one fan in there to help prolong the life.

The spacing of my LEDs are 1up Cree XPG & XRE with 1" spacing (1 per 2 inches.)

 

[nreefer]

Thanks for the great suggestions. I also have a dedicated HRV for the canopy which is changing the air very frequently.
The spacing will be 2 inch centers on the LED's so 1 inch between stars.
I looked at adding more fans but I am afraid the compounded noise will be too much with 9 or 12 fans. I was hoping that if I placed them strategically then I could just use the 6. I will have the splash shield so the air will be forced down into the shield and then come up between the channels. The fans are 55 cfm so pretty good air flow on them.

I will have 28 led's per U channel (10 CW, 18 RB) with a spacing of 1 inch between each U-channel.
The thickness of the aluminum is between 10 and 11 gauge so pretty thick.

What about this layout of fans for in between my first two options?

<a href="https://picasaweb.google.com/lh/photo/dXg7066NW600KELFDDTBqUGwvVygLUjeaAK_hyYqfGU?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/_jiSQPR-FAUI/TVgaZwgNu8I/AAAAAAAAEWM/o6qCpKqKgtY/s400/DSC07028.JPG" height="400" width="300" /></a>

 

[username in use]

I worry about those two outside channels without any direct air flow.

 

[BluScrnOdeth]

Honestly i think you might have to do a trial run without mounting the fans. If you see your fans, even with then staggered, you have 5 rails without a fan above them. Though I agree with you that it may cause enough air flow to bounce back up and cool the other channels. However, the opposite side of the railing (farthest form the fan) will be the warmest. Is it a big deal, only testing will tell. I think it "could" be.

Are you going to mount them directly on top like in your pictures?

 

[username in use]

What about a couple of larger fans, I know you already have those, but some larger ones that can cover more space might make more sense in this case.
these are 250mm

http://www.coolerguys.com/250sf.html

 

[BluScrnOdeth]

If you insist on doing it this way i would do option 1 in this case as long as you have some side skirts to help deflect the side air up. 55cfm is a lot of air and i think that they should be fine this way. I would only stagger them in 3 rows of 2-3 fans if they were put an a 45 degree angle to blow straight down the rails.

 

[nreefer]

The splash shield will have 1 inch side skirts on it to keep the acrylic rigid so it doesn't warp and this should aid in redirecting the air back up thru the U channels.

I think I will get 2 more fans and run 4 sets of 2 mounted side by side. This way I will get the most even coverage and I can always dial the fan speed down if I need to. From what I read it isn't air speed more just even air turn over all the aluminum surface area.

See picture of what I mean using my 6 existing fans, just image 2 more at the far end.

<a href="https://picasaweb.google.com/lh/photo/ZqTCOBz6eGz3sBAevwY31UGwvVygLUjeaAK_hyYqfGU?feat=embedwebsite"><img src="https://lh5.googleusercontent.com/_jiSQPR-FAUI/TVgtGVlfIsI/AAAAAAAAEWU/BFOdK4KVUrk/s400/DSC07036.JPG" height="400" width="300" /></a>

 

[BluScrnOdeth]

Yeah, air speed doesnt have much to do with it, moreso just enough volume to cover the channels, but need enough to carry it away as fast as the air warms up. Incorporating another set of fans in your image (option 2) I would feel safe with as thats 1.5' spacing between the fans. And with having 55cfm, it should push enough volume of air to well over all the U channels.

 

[kcress]

If you're not going to do a proper enclosure whose design includes a logical air flow design I wouldn't bother with fans. The size fans you have and the proximity they are to the U-channel will render very spotty ineffective results, while generating an annoying amount of noise.

If you build the proper plenum design I would strive to minimize the annoying noise by using one really large fan just like UNinU suggests or I'd put four of those fans you have in a tight square in the dead center with the only air inlets of the plenum on the ends.

 

[BluScrnOdeth]

If you're not going to do a proper enclosure whose design includes a logical air flow design I wouldn't bother with fans. The size fans you have and the proximity they are to the U-channel will render very spotty ineffective results, while generating an annoying amount of noise.

If you build the proper plenum design I would strive to minimize the annoying noise by using one really large fan just like UNinU suggests or I'd put four of those fans you have in a tight square in the dead center with the only air inlets of the plenum on the ends.

He seems pretty dead set on doing it with the fans that way so all we can do is help him do it the best he can. Hes heating/cooling will be spotty but not enough to be of any concern. Noise would be a concern of mine as well

 

[nreefer]

Hi Kcress, what do you mean by a proper enclosure?

 

[BluScrnOdeth]

Hi Kcress, what do you mean by a proper enclosure?

A proper enclosure is kind of like a computer case. You would think that having the side open with the fans on would allow it to actually cool down more efficient. But actually with having all the sides on you create a wind tunnel and makes sure that the air flows evenly by everything and doesnt miss a spot to the best of the designs ability.

Also fans should pull air, not push unless you are doing spot cooling.

 

[nreefer]

My next question is a matter of staggering the LED's for best colour blending
The layout I have works mathamatically best with 10 cw and 18 rb per U channel.
Do you think it really matters if I drill all the U channels so the LED's are lined up like this:

<a href="https://picasaweb.google.com/lh/photo/lFvxpCq5D7vWchAk40bKc0GwvVygLUjeaAK_hyYqfGU?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/_jiSQPR-FAUI/TVhRh5MUySI/AAAAAAAAEWg/SXIsJ7BR7qw/s400/DSC07037.JPG" height="300" width="400" /></a>


Or should I forgo the easy wiring and attempt this:

<a href="https://picasaweb.google.com/lh/photo/RRnqcvTo0PLx-PgnwEuEI0GwvVygLUjeaAK_hyYqfGU?feat=embedwebsite"><img src="https://lh6.googleusercontent.com/_jiSQPR-FAUI/TVhRh-Q21PI/AAAAAAAAEWc/MyfXOxwgP9Q/s400/DSC07039.JPG" height="300" width="400" /></a>

It would mean every other U channel would have 27 LED's
remember I am running this in parallel so the strings have to match