112 Watt "High-Pod"-esque Stealth 13 Gallon Trash Can Grow - Venting Help?

[Crake]

Well, after reading about the high-pod's wild success, I thought I'd emulate one with my own ideas and the resources available to me. So I've created this 6x15w T8 + 1x22w Circline = 112w trash bin. All the structure is built from black foamboard. The downside of the high-pod was that you couldn't get at the plant inside, so I built this around easy removal. It's about 80% done, I just need to finish wiring and figure out where I want the fans. Enough chat! Here are some pics.

The bin, partially assembled:


The top removed:


The apparatus (loosely based on the bomb from "The Rock" ):


A shot of the inside (what's that on the bottom...?):


Activated carbon housed between two sheets of nylon screen, 3/4 of an inch wide :


Holes drilled in the bottom for air to exit:


A closer shot at the light apparatus. The growing container will be suspended just above this on a wire stand so it doesn't restrict airflow through the carbon. Lights will be housed in tubes to hopefully shield the plants from getting burned on them. (Black tape is just there to hold wiring in place, hot glue is used for structural adhesive) :


The 22w circline with screw in ballast that will sit on top:


The ballasts, fans, and wires all laid out (they will cap the container and sit inside the bin):


A closer shot those of all that ugly stuff:


So that's what I've got so far! :Biggrin: Now what I came here to ask from some hopefully more experienced grow-box engineers . Should I mount the fans on the top or the side? If I mount them on the top like this:

Pros: it would be most stealthy.
Cons: I'd have to fix some sort of prop to keep the lid from closing while the fans are operating. The fans would be in a nice place for the most heat to be controlled. Maybe there would be some way to fabricate an electromagnet or actuator to open the lid when the thing is running?


If I mount fans on the side like this:

Pros: I'd be able to put a nice light trap on the side of the trash can.
Cons: but that means I'd probably have to keep it up against a corner so it's not visible.

And how much airflow will I need to keep this cool inside? The air is obviously being pushed through the scrubber at the bottom. The ballasts are external, so hopefully that will keep the inside temps down a little bit.

FYI: All possible interior black areas will be covered with reflective tape. Obviously it looks like crap, generally. If I had the tools, I'd use wood for all of the structure. It would be a much cleaner and sturdier design. The entire thing is air tight aside from future entrances through fans and the exit through the scrubber.

 

[igrowone]

i've done something similar, a 'tube' 38 inches tall
as long as you have air flow through the top, you'll be good
i did the top with a single pc case fan, keeps temps under 80 no problem

 

[Crake]

i've done something similar, a 'tube' 38 inches tall
as long as you have air flow through the top, you'll be good
i did the top with a single pc case fan, keeps temps under 80 no problem

What was your wattage?

 

[fatigues]

A fan needs to be at the top - that's where the heat rises. Sucking it back out the bottom is just chasing your tail.

In a container that small, a fan needs to always be on (admittedly, not running as briskly with lights off). Your plants always need air - whether lights are on or not.

I'd look to building Scrubninja's DIY darkroom louvers in the area where the lid is and you should be happy. The charcoal filter obviously needs to come up after the plant - and not before it on the bottom of your can. (I would not put a whole lot of trust in charcoal filter cloth, either.)

You will probably need to install another louver on the bottom of your can I think. Does not look to me like there is sufficient airflow permitted by those holes. The High-pods light traps may prove useful for this.

 

[igrowone]

What was your wattage?

total 81w(78w during flower), bit less than yours
but not that big a difference

if you have a moving air column through the top, that is what you need, may be able to do that with fan mounted lower
top mounted fan may be a bit easier cooling wise, the moving column holds true provided there are no escape points for the air
but if you have a tube with airflow, and the only exit/entry points are the top and bottom, it ought not matter where the push of air comes from

 

[Crake]

A fan needs to be at the top - that's where the heat rises. Sucking it back out the bottom is just chasing your tail.

In a container that small, a fan needs to always be on (asmittedly, not running as briskly with lights off). Your plants always need air - whether lights are on or not.

I'd look to building Scrubninja's DIY darkroom louvers in the area where the lid is and you should be happy. The charcoal filter obviously needs to come up after the plant - and not before it on the bottom of your can. (I would not put a whole lot of trust in charcoal filter cloth, either.)

You will probably need to install another louver on the bottom of your can I think. Does not look to me like there is sufficient airflow permitted by those holes. The High-pods light traps may prove useful for this.

Hey Fatigues, thanks for the stopping by and the input!

The filter is after the plant in either case. See:

Also I don't think there would be room for any louvers up there. There's lots of hardware I'm trying to fit into that space (3 T8 ballasts, the circline ballast, 2 fans--maybe 4 if I can fit them inline, a power strip, wiring, 12v transformer).

Also, scrubber is not cloth, it's activated carbon housed between two stretched sheets of nylon screen.

 

[igrowone]

based on your last pic, you definitely want the fans at the top
that will remove the pool of heat that will build there

 

[Crake]

Ok how's this look (pardon my crude drawings):

Like I said I'll need to figure out a way to prop the door open enough to let air in while the fans are operating. The door flap could then act as a light trap for dark periods. Maybe I could operate a single fan at slow speeds to keep air circulating during that time.

Here's a pic of the diagram on the can to help everyone get a better idea of what I'm talking about:

 

[igrowone]

Ok how's this look (pardon my crude drawings):

Like I said I'll need to figure out a way to prop the door open enough to let air in while the fans are operating. The door flap could then act as a light trap for dark periods. Maybe I could operate a single fan at slow speeds to keep air circulating during that time.

Here's a pic of the diagram on the can to help everyone get a better idea of what I'm talking about:

this looks good to me, i have 3 cfl's at the top of my tube
so the heat profile here is a bit different
i've been growing northern lights so far, smell has been so low i've done without the carbon filter
it does take a good pressure to push through the filter

 

[ScrubNinja]

Crake, that's way cool, dude. Been waiting for someone to do this with old school fluoros How come you're pushing the air down though? Heat rises and you may have to fight it. Have you done any heat runs yet?

Also, my recommendation is to avoid the reflective tape. That's what killed my attempt at a high pod clone. I had like 30 something watts, and a 110cfm fan on top with plenty of intakes but it still never ran cool despite being only around 1 cubic ft. It just reflects too much radiant heat around inside, well, that's what I blamed anyway. I used mylar tape - Turned it into a convection oven.

Best of luck.

(did you push down, Igrowone?)

(edit: Did the high-pod push down? I might be trippin')

 

[3dDream]

This is a sweet idea. People will think I am very trash conscious because I'll have a can in every room. I hope nobody tries to throw anything away. Maybe you should have fake trash so it looks full.

If you can make a layer of foam at the top you could prob fit a 6" fan at the top and pull the air through a carbon layer. You could intake from the bottom.

 

[igrowone]

(did you push down, Igrowone?)

actually, i did it both ways
built a 2nd tube and installed fan backwards(inadvertently)
both seemed to run about the same temp wise

 

[:-(]

I have this same trash can in my kitchen!!! This looks really clean, I'll stay tuned.
you may consider using the round 4 inch dark room louvre, maybe 2 - 4 of them on the bottom would solve your ventilation issues.
http://www.builderdepot.com/browse.ihtml?pid=11367&step=5&prodstoreid=301
Good luck!

 

[cork144]

dont vent pushing into the area man, vent directly out of the top, otherwise youll just be building posative pressure and the fans wont work properly

 

[Crake]

ScrubNinja Always a pleasure! Thanks for stopping by and giving some input. It is a bit unfortunate that I'm pushing the intake downward against the tendency of the rising heat, but I don't want the carbon filter on top. I'm prepared to fight the heat with enough internal static pressure to move air rapidly through the scrubber. The ambient temperature of the area where this will reside will be in the mid 60's (*F) so I'm hoping it will stay around 80*F in there. I won't know until I do a dry run. Only 30 watts and you weren't able to cool a volume of about half this size? That's not very reassuring. Hopefully my external ballasts and inline fans will make a difference here. I'm kind of a trial and error person when it comes to constructing these so I won't know until I do a dry run. As for the mylar tape, where'd you get that? I have some space blankets but I hate to resort to adhering that material inside of the trash can--tape would be much easier.

Also, the high-pod was pulling air up, I think. Problem was it was a completely unstealthy design, though.

3dDream Good idea. I may need to do that if my dry run doesn't turn out well.

Thanks for the input dude! I'm really glad you posted that link to the louvre. I was trying to find a small enough one for my last stealth box and eventually just made my own. If I need to change the design of this I'll definitely have to pick up a couple of those!

cork144 Thanks for the advice friend! We'll see how the dry run goes. The positive pressure would definitely add resistance to the fans' ability to push at their rated CFM. I may have to consider this if things don't work out well with the test run. Peace!


As for progress, I haven't made any--been busy with work and I still need to pick up a transformer for the fans.

 

[ScrubNinja]

G'day Crake no worries I got the tape from bunnings, it's a similar store to home depot. It doesn't have any inscriptions or company names on it sadly.

 

[Crake]

Just an update--I ended up scrapping this idea eventually. I ran into a huge unforeseeable problem--the fluoros require a grounded reflector within a few centimeters to ignite with the type of ballast I was using (electromagnetic). I could have rewired them with a different type of ballast but I didn't have the energy. I also tried making the entire inside of the pod a grounded reflector out of sheet metal but that didn't work.

Instead I picked up a 70W HPS and restructured the internal apparatus with wood dowels and circular plywood platforms. I also placed the fans on the bottom and moved the scrubber to the top. Unfortunately, even with the fans on the bottom the inside temps got too high (90 degrees+). With some beefier fans it might have worked.

I think the best route to take with this type of grow would be to have an HPS in a cooltube down the middle that's can be slid up and down to a desired height. Or even some PLLs. I may end up giving that a shot somewhere down the line, but for now this project is on hold.