150w HPS Club and Resource Guide......

[TheOneWill]

What I plan on doing is take a 120mm fan pulling air from the outside an pushing through the tubing going to the cool tube. Then have an exhaust fan hooked up to the other side where it would look like a semi circle. (if just one of them is fast enough I just might use one fan for this. Like just use one 120mm 9000rpm fan to exhaust)

Then have a 120mm on one side and a 80mm on the other side. One for intake(120mm) and one for exhaust (80mm). So there will be little pressure. But even right now I'm having problems with particles in the air. So I plan on getting some type of screen to filter it out.

 

[DiscoDuck]

TheOneWill, that's exactly what Pipedream is saying. An active intake will increase the dust and dirt that ends up in your cabinet. Trust hundreds (maybe even thousands) of ICMag growers, you will not need to use fans for inputs, save them instead for exhaust applications. Here's a suggestion:

Here are the intake holes in my cabinet. I need twice the intake as I have exhaust. Since I have a 4" exhaust, I'll need at least eight inches of intake. In this case my passive intake holes are 1 inch in diameter. This means I need at least eight 1 inch holes (passive, no fan) in my cabinet. I want the temps to be as cool as possible so I put the intake holes in the lowest part of the cabinet as possible, in this case the floor. I cut 1 inch pieces of scotchbrite and put one piece in each hole to keep critters and dust out of the cabinet. This also acts like a light trap. Since this will reduce airflow, I increased my intake to 14 inches.



Here's a shot of my exhaust. As air is heated inside the cabinet it rises to the top. The exhaust fan pushes the heated air out of the cabinet while it simultaneously pulls cool air through the passive intakes, making intake fans unnecessary. Put your exhaust as high as possible.




Now here's a shot of the whole thing working. As the exhaust fan pushes hot air out of the cabinet it sucks air through the floor intakes, through the grow chambers, into the utility room and out the exhaust.




You mentioned you're gonna vent your cool tube, a passive intake will work for this just as well. Good luck with your design.

 

[BRNEYDBVR]

TheOneWill-

Use one 120mm for the cooltube.
Use one 120mm for exhaust with passive intake.

Your gonna need to incorporate a carbon filter somewhere in the mix and because this causes airflow restrictions... a larger exhaust fan may be needed.

I use one 140cfm dayton that pulls thru several 8" darkroom louvers and blows through the carbon filter. Pushing air thru the filter is not as efficient as pulling air thru it....but this is what works for my situation.

Good Luck with the design.
Please take some pics and let us know how it goes.

 

[Guest]

Hey guys,

It's been a while since I popped into the 150 HPS club. I see Pipedream and Sugabear are still kicking butt!!!

I've got some LUI and Dr. Atomic Thai-Lights beans germinating and will be running a two plant grow in my 150 HPS + 126 CFL cab.

I'd like to comment on passive intakes. Almost everone undersizes the intakes because they don't calculate out the area of the ducting correctly. The intake has to be twice the Area of the exhaust to reduce a pressure drop at the intake.

You need the old pi R squared formula or pi D squared / 4 to get the right area for a circle. A 4" fan/duct needs a 25 sqin intake or a 5x5 hole. A 6" fan/duct needs 56 sqin or roughly a 8x8 in hole.

Incidentally, Flow = K * sqrt(pressure)*Area where K is a constant for each growbox.

Whenever you are dealing with a low flow problem there are two possible solutions. A bigger fan produces more pressure but a 4x larger fan only produces 2x flow.

Increasing the Area by 2x will increase the Flow by 2x.

So by increasing your intakes to a maximum of 2x the area of the exhast, is the easiest fix to improve air flow problems.

 

[TheOneWill]

Ok so I would need just a bigger exhaust fan instead of intake.

 

[BRNEYDBVR]

Maybe....but not necessarily. Is your intake area 2X the size of the exhaust?

As Red_Greenery stated.... This is imperative for proper airflow.

Make sure your intake is 2X larger than the exhaust... Use your 120mm fan and check your temps.
If they are not where you want them... Redesign with a larger fan.

If you haven't checked it out.... I suggest that you look through Red's 150 cab thread.

 

[Greeseyder]

Update: my Cripple Creek mum is flowering away .....lovin' the 150w! Plus I got 3 Karmatrain babies up & rockin' in the Moonshine Mix.....I have included some sample pics of a finishing Karmatrain these are NOT repeat NOT my pics but are Clonemans Karmatrain......I hope to be so lucky!!!!!
G

 

[TheOneWill]

I haven't yet updated the cab or bought the parts because I'm waiting on my first set of plants to finish.

 

[Poker_Toker]

Bro dimensions dimensions, that looks to be the perfect size for me to build. I eventually want to have a box like that with my 175mh for veg and 400 hps for flower. pm me the dimensions if you can, thanks

 

[DiscoDuck]

thanks, Poker_Toker. I've only got a 150hps, 60 watt cfl, a big ass fan and my temps are already approaching 80 degrees f. Take a look at the "400 watt hps club" and compare the cabinet sizes with 150hps. They're usually alot bigger, even two and three times as big as typical 150s.

I'll be lucky to pull three ounces out of this box at harvest. Your 400 watter can do a half pound easy if the box is big enough.

Thanks again for the compliment.

 

[Guest]

Ok so I would need just a bigger exhaust fan instead of intake.

Check out this airflow sizing chart for HPS lighting to pick your fan size.

 

[DiscoDuck]

This stuff is taking forever...

bagseed.....day 79



does anybody grow strains that take longer than 12 weeks?




I heard green_grow mention his plant smelled like turpentine. This stuff does too. It may be inflammable, lol.

 

[vintner]

Red Greenery: I don't mean to sound ignorant, but what is that chart supposed to teach me?

 

[the_man]

vinter

what you do is find out what size light you want

then follow the right colored line to the left

on the left hand side of the chart there is 10-1000 cfm

the cfm is the rating of the fan you want to buy

 

[vintner]

vinter

what you do is find out what size light you want

then follow the right colored line to the left

on the left hand side of the chart there is 10-1000 cfm

the cfm is the rating of the fan you want to buy

If what you're saying is correct, that means I need a nearly 500cfm fan for a 150watt light. Maybe I still don't get it.

 

[the_man]

500 cfm seems correct

but i just finshied a cabinet with two two top motor 120mm case fans 80cfm

with a fan speed controller $10.00 and the two case fans 8.00 each with shipping

i can vary the temp in my cabinet from 70 to 80 degs

last night i shut down the fans and let it run hottest it got with the 150 was 90

i'm not sure what you are building

 

[TheOneWill]

Check out this airflow sizing chart for HPS lighting to pick your fan size.

Looks like I'm gonna be doing a 150watt hps.

 

[phr3d0m2gr0]

If what you're saying is correct, that means I need a nearly 500cfm fan for a 150watt light. Maybe I still don't get it.

You guys are reading it wrong. The bottom of the graph show temp difference from room temperature, so depending on how cold the room you have your box in you can adjust your cooling. If you have a 60 degree room you want the temp around 75 in the cab you would go to about 15 degrees on the bottom and then up until you hit the 150watt line. The fan size would be about a 40-60CFM.

A 100CFM would make you cabinet about 4 degrees above room temp. Of course this is just a guide it's not dead on so i would over estimate and get the biggest fan you can (within a reasonable range 100-300CFM, a 300CFM would allow for more lights in the future).

-Phr3

 

[TheOneWill]

My room stays around 75-80 degrees and my cab is in my closet. My room is slightly cooler now since its winter time. So my cab stays in between 75-85. Thats with 252 watts of cfl.

 

[vintner]

Hey, Thanks phr3d0m2gr0: Now it makes sence! And I can see how the chart is just a guide, cause you still have to consider the size of your grow box and ambien temps.