Help me with ventilation: 400w hps aircool in tall cabinet / stealth

So I am wanting to grow some Lowryder #2 x ak47 from attitudeseeds. Im wanting to grow in this cabinet that is: 31.25" w x 19.75" d x 73.88" h.

I was thinking of going 400w hps aircooled and lowryder in 9L soil containers. I am of course worried about heat so my attached photo is me trying to figure out how to vent this cabinet.

In my picture I have a 6" inline fan pushing air through the air cooled hood and out the exhaust. Can the ducting be open ended for the air from the intake to flow out?

What is the optimal way to vent this type of grow.

Thank you.

youve got it backwards, you want the fan sucking air through the hood. is the fan you have an inline duct booster fan? Cuz duct booster fans dont work worth a damn if they have any sort of resistance.

I agree with Darkd, suck don't blow. Is the lamp going to cool with box air or room air? 400W for less than 4 sq feet is a ton of lamp, more lamp more heat. A 150W would give you about 40W/sq ft in there. Just my thoughts, good luck.

Hmm...You should be able to put the 400w in there but it might be advisable to buy a balast that is dimmiable like 250/400w just in case you run into heat problems. Try to vent the out going air out of the room you are taking air in from as releasing the hot air back into the room to be reintroduced into the system will lead to even higher tempatures. So try to get it to fresh air if you can. You can also pull air from outside depending on the climate which doesn't work for me as during the summer temps outside range from 90 to 100+.

darkdestruction420, yes inline fan, maybe 4" or 6". If I had passive intake would I be creating negative pressure?


ow.douglas, I should most likely shoot for fresh air if im going with 400w. I have a window near where I want the box so I have to figure that out.


The reason I was thinking 400w HPS is yield on these plants. Im only going to grow 5 Lowryder #2 x ak47 and maybe work towards a perpetual grow from seed. 5 plants is what I can legally grow without stressing out all the time.


Would a 400w hps increase yields moreso than a 250w hps in my box, with 5 autoflowering plants.

Probably smoke about 2 oz a month (not just me) so I read about Lowryder potentially yielding about 5 oz for a good grow.

I was also thinking of growing in soil as I am worried about hydro reservoir temperatures in such an enclosed space?

Thank you for replies folks. I am going to get back to reading now.

Durr

Durr, if you use air from outside the box you will not create negative pressure for a passive intake, you will need another fan to exhaust box air. I will end up in the minority here but, if you use a smaller lamp you will be able to keep it closer to the plants. It will also be easier to control the temps inside the box.

How about this design?

Can you hook up a cooltube and have the inline fan pulling out both box exhaust and cooltube exhaust?


I dropped to 250w per your suggestion.

thanks folks

durruti said:

View attachment 1413182


How about this design?

Can you hook up a cooltube and have the inline fan pulling out both box exhaust and cooltube exhaust?


I dropped to 250w per your suggestion.

thanks folks

Click to expand...

This design doesn't look to bad.. Here is what I would recommend.
Your 2 small supply fans at the bottom of the unit are not needed neither is the fan before your 6"inline fan. You should only need one fan and if a 6" fan does not work go with an 8" fan. I would cut a round hole in the bottom of the cabinet as shown and leave it open with back draft dampers installed instead. This will insure that the unit stays negative. inline fans are fine to run just make sure you do not run long amounts of flex if you are using one.
Also if you’re using a 6" fan make sure your filter is not to restrictive. I would also recommend installing a balancing damper in the either the intake for the light tube or on the intake/exhaust inside of the cab. This will enable you to control how much exhaust you have from your cab and your light tube.

I have something like the cool cab from sunlight sheds which is just about the same size as yours. The inline fan sucks fresh air in and pushes it through the ducting, thru the cool tube, cooling the bulb, and exhausting the hot air out the other end. This is mounted near the top of the cab, maybe at the 5' level with the intake and exhaust holes on the back wall spaced apart to each edge. The cool tube is suspended with light hangars. 2 lengths of ducting, a cool tube w/400w and a inline fan is what you need for this part. No need for carbon filter on this part of the set up as the air is not mixed with the plant aroma. I have a bathroom fan mounted on the inside back wall about 2.5' from the bottom with a carbon filter on the exhaust end on the back of the cab (outside). This is what cleans my aroma. I also have an ozone generator.....no smell in my house. I have 2 small coffin fans mounted on the bottom bringing in fresh air. My cab is always always always 72-74 degrees.

I have re done your picture.

Rockballer, Thank you very much for the edit of my picture. I was just compiling my questions for you. It looks great. Do you think the 250w would be good or could I go with a 400w with a 8" inline?

aslong as your pressure drop isn't any higher than a 1/4" across your filter i don't see it being a problem. It all depengs on your fan curve. what make and model number are you looking at using

I am really complicating this... It should be fine.

http://www.canadianwholesalehydroponics.com/products.cfm?p_id=111&show_details=1&catpage=2
8" can fan 737 cfm

are vortex better?

ya 737 CFM @ 0 static pressure.. I love how these companies advertise their fans.
I am a mechanical engineer and know HVAC systems but I have no idea when it comes to lights...LOL

so lets just say roughly 4-550 CFM after everything has been connected. how much cooling does your light require?

I'm planning the cabinet build so I have yet to buy the light setup I was looking at. I was thinking a digital ballast that runs 250/400w hps. Shoot for 400w hps if it works out, otherwise drop to 250w.

Do you know what the 8" can fans sound like?

I find grow equipment hard to shop for, so I like talking to people who've used it / reviews.


I was aiming to grow Lowryder #2 x ak47 from attitude seeds and hope for a large enough yield. I am growing in soil too.

Any thoughts?

This is a rough design. The carbon filter before the fan only cost about $120 for 6 filters. only $20 a filter, These filters are tested and work great, alot of residential buildings use them in their garbage rooms for the smell.
The next is the fan. I chose a Greenheck cabinet fan Model:CSP-A200
All the dimensions are on their website for the ducting.
A small little 4 or 6" fan flex ducted to your light on a timer should work good. This way your fan does not need to run 24/7

http://www.greenheck.com/media/pdf/catalogs/SPCSP_catalog.pdf

http://www.airfiltration.ca/furnace-filters/made-to-measure-filters.htm

Let me know what you think