CXA3590 Build Plan

Doer · Mar 8, 2015

Oh! Well that is funny. And I like funny. You just left out the clue. Help me. Help me.

I am being held at a secret location by the Army of the 12 HIDs. They are hideous. But, I have to admit that once you get to know them and understand their beliefs, they seem like a bunch of nice fellows. I get a light in my closet for 2 hour a day now, and after I learn the Litany Against LED I can have an hour of standing up straight and 2 more hours of nice wonderful soothing HID (blessed be its name) illumination.

Doer · Mar 8, 2015

Really @churchhaze I hope you are as stoned as I.

What I think this says is, if one size heat sink will work passively, then adding airflow can allow a 3 times SMALLER one.

Or put another way I would need 12 feet of this sink for what I can do with 4 feet and a fan, namely dissipate 600w and exhaust it, even if it the exhaust air is "close" to ambient.

Abiqua · Mar 8, 2015

Doer said:
Really @churchhaze I hope you are as stoned as I.

What I think this says is, if one size heat sink will work passively, then adding airflow can allow a 3 times SMALLER one.

Or put another way I would need 12 feet of this sink for what I can do with 4 feet and a fan, namely dissipate 600w and exhaust it, even if it the exhaust air is "close" to ambient.

From supra who has been doing all the testing.....a lower air speed with similar volume seems to be better at achieving 3x times the amount of cooling versus a higher air speed......

Doer · Mar 8, 2015

That is quite possible. I have only gone by these quoted multipliers for lowering the quoted C/W/3 of a heat sink. And according to the chart higher fan speeds create a better multiplier and lowers the C/W/3 even better.

These are certainly not experiments, yet.

I think what you might be taking about is the info on running fans at 5v, 9v and 12v. And adding that wattage to calculate efficiency.

But, remember that was blowing straight down in free air where you end up recirculating the heat.

With an evacuated tube adding a horizontal un-impeded air flow only makes thing better the faster the flow.

Why? Two different system all together. The down fan, hits the bottom wall in a few inches and that causes back pressures on the fan. So, of course, there is a limit to how fast an airflow you can get. So, of course, to run the fan faster is just drinking juice for no effect.

On a linear sink I can have what ever air flow I need.

Devildenis69 · Mar 8, 2015

A very interesting project, I'll follow it.
Have you considered the light losses caused by the cool tube ? not a big deal ?
good luck with your lights 8-)

tightpockt · Mar 8, 2015

I'm imagining square ducting with little holes drilled out for the COBS to peak through with the rest of the setup inside the duct. That'd be pretty cool...Maybe attach a filter to one end and kill two birds with one stone like someone said earlier

Devildenis69 · Mar 8, 2015

drill the tube is a bit tricky, but imo it's the way to go

Abiqua · Mar 8, 2015

bicit · Mar 8, 2015

Well it's an interesting idea, but I like the analogy churchhaze used. Seems like you're trying to jump over a $100 bill to pick up a few pennies. Especially if you're using the same vortex fan to vent your room and cool the lights. It would make more sense for a cool tube if you were trying to set up a sealed room. Ventilating the room and the light on separate streams.

However since you plan on using the same fan for both tasks. It would make more sense to spread the lights out over the canopy more evenly, and simply vent the room with the fan. Really the cobs don't need much airflow to stay cool. You'll experience better results as well even if the Tc/Tj are slightly higher and efficiency slightly lower on paper.

Doer · Mar 8, 2015

bicit said:
Well it's an interesting idea, but I like the analogy churchhaze used. Seems like you're trying to jump over a $100 bill to pick up a few pennies. Especially if you're using the same vortex fan to vent your room and cool the lights. It would make more sense for a cool tube if you were trying to set up a sealed room. Ventilating the room and the light on separate streams.

However since you plan on using the same fan for both tasks. It would make more sense to spread the lights out over the canopy more evenly, and simply vent the room with the fan. Really the cobs don't need much airflow to stay cool. You'll experience better results as well even if the Tc/Tj are slightly higher and efficiency slightly lower on paper.

No, the room has an A/C. I don't want to load that anymore than absolutely necessary.
The will also have a passive intake of fresh air, circulating fans, etc, and passive exhaust. I simply want to run 600w on a 4" x 5.88 inches long heat sink instead of using a 12 footer of the same size, for passive.

So, think bedroom size, not a closet. And think 3 of these all exhausted from the space.

And for cost, you can't beat it. A metal duct is $50, the heat sink is $90 a good fan for this I already have.
Figure the LFM of a 8" axial fan cool pipe. It is pretty good.

But, I am beginning to see what you mean. If these will run closer to ambient than I thought it is better to go with individual 100w units with 6 Rosewill RCX-Z200, just hang them on chains maybe. It will help with the A/C re-circulation, as someone said.

Uh.....I'll take the $100 bill?

Doer · Mar 8, 2015

My thread is open for all honest help. I am thinking like you all. I think a healthy mania is all I have at times.

And I see how one can circle and circle, with all the ways to do it. Why did you give up on individual COBs on sinks?

It does probably make for a wiring head ache, for one thing.

Doer · Mar 8, 2015

churchhaze said:
Honestly, I have no idea what the best design is or if there really is one best design. I've been tearing my hair out thinking of different ways things can be setup. What I can tell you is that I've moved away from 6 individually hanging cobs in favor of a few cobs per heat sink... Designing heat sinks gives me a headache...

Some recent designs if you haven't seen them...

There's the 80W design based on 4x vero 18 at 700mA, which is semi-passive.. 10" profile cut to 10" length. about 70C without fans, so optional. I put a 120mm fan on each.

View attachment 3367710 View attachment 3367711 View attachment 3367728

There's the 20W veg lamps... 2x vero 18 5000k at 350mA on 12" profile cut to 5", completely passive with the extremely short channels and high amount of intakes.
View attachment 3367724 View attachment 3367725 View attachment 3367726

Then there's the design I made more recently... the... 193W cxb2530 3000k U2 bins in one string across 3 sinks. These are 10" profile cut to 15", and the middle cut to 5". Also semi-passive and the big panels also get to about 70C. I didn't want to make it 1 long piece so I have shorter channels, and more intakes/exhausts. I will likely put 2x 120mm fans on each large sink, but it's fine without it.

View attachment 3367719 View attachment 3367720

Sorry to thread jack, just meaning to give an idea of my own designs over the past few months. I keep thinking of different ways to setup heat sinks... I've got Heat Sink Mania...

So, are you bragging or complaining? Oh, you are commiserating!

And you know it is pretty easy to experiment. And I say, good job. Thanks for sharing.

But, say, what is the problem you keep circling? What do you want next?

Doer · Mar 8, 2015

Devildenis69 said:
A very interesting project, I'll follow it.
Have you considered the light losses caused by the cool tube ? not a big deal ?
good luck with your lights

Oh sorry, cool tube is a goof. I use water cooled HPS. It was just to illustrate the idea of forced air.
I could have been more clear.

What I would do, is make a shroud over the top of the sink and blast air thru it. That way you get more efficiency from the heat sink.

So, on the bottom are the LEDS but the other 3 sides are sheet metal, attached to but insulated from the heat sink.

So, no glass tube. Sorry. LEDs are bare. Heat sink fins are surrounded by a duct.

Doer · Mar 8, 2015

Sorry what? I did not hear your last. I have Stockton syndrome.

Please steer me toward designs that are actually good.

Doer · Mar 8, 2015

tightpockt said:
I'm imagining square ducting with little holes drilled out for the COBS to peak through with the rest of the setup inside the duct. That'd be pretty cool...Maybe attach a filter to one end and kill two birds with one stone like someone said earlier

I was thinking leaving the bottom out all together. And yes, this way you can have a convenient filter. One of the things about HID is you have to clean the tubes unless you hang them free.

Doer · Mar 8, 2015

Right so if single ones are a wiring mess, a 3 sided duct has room to put the drivers under the hood, so to speak. Easier to hang a 5" wide rail. And then you could fill a room with 3 of those, 1800w potentially.

1 fan, one fail safe, less hassle, cleaner look, cost the same, with filters....

Doer · Mar 8, 2015

For example, here is one, 8 x 8 inches. And I kinda liking @tightpockt idea of just making cut outs in the bottom for the LEDs.

Length: 5'; Size: 8" x 8";

Order # :M90-023
Mfg. # :100-085
Brand :Snappy

bicit · Mar 8, 2015

Doer said:
No, the room has an A/C. I don't want to load that anymore than absolutely necessary.
The will also have a passive intake of fresh air, circulating fans, etc, and passive exhaust. I simply want to run 600w on a 4" x 5.88 inches long heat sink instead of using a 12 footer of the same size, for passive.

So, think bedroom size, not a closet. And think 3 of these all exhausted from the space.

And for cost, you can't beat it. A metal duct is $50, the heat sink is $90 a good fan for this I already have.
Figure the LFM of a 8" axial fan cool pipe. It is pretty good.

But, I am beginning to see what you mean. If these will run closer to ambient than I thought it is better to go with individual 100w units with 6 Rosewill RCX-Z200, just hang them on chains maybe. It will help with the A/C re-circulation, as someone said.

Uh.....I'll take the $100 bill?

Is the 8" fan sucking air out of the grow room? Or does it have a separate intake outside of the grow room that simply cools the light? I'm having a hard time understanding just what you're trying to do. Are they all inline with each other? Every 90* turn is going to reduce your airflow considerably...

If you're venting the room with the fan than it would be pointless to put it in a cool tube. It won't add anymore load to the AC and you should focus on distributing the light. Break it up into 3, 24", 200w bars instead of a solid 48" bar. You'll get better cooling and distribution.

Doer · Mar 8, 2015

Intake outside (cool air from under the house) and output outside of grow.( up thru attic) And why? More watts. Forced air mean you can cool the heat sink much better. You can drive them a bit harder or what ever you do with the trade off.

But, now with the new recommendation of 25 sq cm per watt, for active, well, I am rethinking.

IAC, 8" is great way to move air.

So, this mean I can go with 900w or more on this one sink and use a fan like this, bolt on to the square tube.

http://www.bhphotovideo.com/bnh/controller/home?O=&sku=1047921&gclid=CjwKEAiAg_CnBRDc1N_wuoCiwyESJABpBuMXFl5qHgxBoj5LnwCBr-olMoS9pWxh0vjWhdlqV1xsGRoCZiDw_wcB&Q=&is=REG&A=details

120 cfm should be plenty.

Then put this or something like it on the other end.

Doer · Mar 8, 2015

I also see the point if the temps are not too high to just let the A/C deal with it. Don't try to exhaust the air.

Fan on one end, filter on the other end an 8" square tube 6 foot long or more for spread
3 chunks of heat sink with
1 diver each each, running 3 COBs per @ 300w.

What could possibly go wrong?

CXA3590 Build Plan

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