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newbie fridge grow

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wooderson420

Member
howdy yall...

long time lurker, first time poster

built a cab over the weekend with the help of a family member out of an old fridge. got my veg room on top in the freezer, grow room on the bottom.

up top there are 2 doubled up T5 lights, down below there is a 150w hps, and some supplementary lighting (cfls) that arent turned on right now .

i have my air intake (80cfm fan) down low, between the two chambers is a duct with a light trap. up top in the freezer i have my carbon filter attached to an in line 100 cfm fan, pulling out the air.

the idea was to be able to pull it off with only two fans, and one filter...

now heres the problem, temp is hovering at around 95 degrees in the flower room, and 84-85 in the veg room.

anybody got any ideas how to get it down? currently trying a frozen 2 liter bottle in the grow rm to see if that helps cool it off a bit.

other ideas include stronger fans, or ditching the hps light all together for a ton of T5s or a cool tube.
 
Nicoli

Nicoli

Active member
Veteran
More airflow.. heh.

So the air temp in the room without a grow going is 95? or this is operating temps?
 
touchofgrey

touchofgrey

Active member
The short answer is you're not getting enough airflow. A 100 cfm fan should do better than than that. If you've read up on the information that is available around here you know that there are a number of things that can restrict your flow. What are the specifics of the fan? There are some inline fans out there that don't have the oomph to push through a filter. Also, If you've got just an 80mm intake hole that could be a restriction if that fan isn't really doing it's job. What is the filter? It could be causing a restriction.

Also, what are you ambient temps?

Here's a chart that show what you should get for temp rise based on the wattage you are running. For a couple hundred watts even 60 cfm net should not be much more that a 10 degree rise.
 
touchofgrey

touchofgrey

Active member
Also, if you check the microcabinet thread in my signature you can see how I tested the airflow by taping plastic bag over the outlet, timing it filling and calculating the airflow. That way you can know know what you're really getting.
 
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wooderson420

Member
touchofgrey said:
Also, if you check the microcabinet thread in my signature you can see how I tested the airflow by taping plastic bag over the outlet, timing it filling and calculating the airflow. That way you can know know what you're really getting.
Click to expand...

Thanks man... that chart is awesome.

I am going to have to try this! I still have a couple of weeks before my clones get large enough to worry a bunch, but I want to get this thing fixed now.

Temps outside the cab, which is in my fairly insulated on 3 walls, (townhouse garage) fluctuate from the low 60s to high 70s depending on the time of the year. Right now its midnight and its 63 in my garage, due to the heat coming off of the houses. Im terrified if these are the temps Im getting now, imagine summer time!

Ill post some pics w/ specs in a second so you can see what Im talking about
 
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wooderson420

Member
Ok guys here are some pics...try not to laugh to much at the newb.

Wait a sec, how the f do you post pics? Be back soon as I figure that out...
 
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wooderson420

Member
Ok I think I got it figured out... here is a pic of the cab in operation right now. Being held shut by bungee cords b/c I have yet to fit it with locks.

DSC_0001.jpg


First off is the veg room, the can looking thing in front of the plants is a home made light trap/vent that allows air flow from below. air moves out of it pretty good, even with the top door open. No light at all. On the left you can see a DIY carbon filter, backed by a 6 inch in line booster fan. The fan is currently sucking air through the cab, into the filter and out. This is the fan I have http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053

DSC_0003.jpg


Next up, the bottom part...

DSC_0005.jpg


On your right is the line in, going all the way up and blowing on the 150 watt hps. It is an 80 cfm bathroom fart fan from home depot, attached to 3" duct. To your left is the line out, attached to the can above in the veg room, the air is being moved through by the filter fan above. I had this line sucking out by the light, but even though shorter, I had to bend it and it didnt seem to do much. Seem to get the best results with it long and straight. Last but not least is my attempt to cool the air with a frozen plastic jug o' ice there in the middle... guessing it would do better closer to one of the ducts.

All said and done, the air flow seems to be fine inside, its definitely moving at a rapid pace, just not enough I guess! Im starting to learn this isnt as easy as I thought it would be! But I am not gonna let it beat me.

Was at the hydro shop today looking at fans. Likely will replace what I have in the next couple of days to see if that helps. Maybe relocate the carbon filter outside. The reason its inside is that I didnt want to have the fridge off of the wall, wanted it to look normal and not stick out.

Thanks for trying to help out a new guy!
 
touchofgrey

touchofgrey

Active member
I think what you have is a restriction in the filter that is more than your fans can handle. Do you feel a good airflow coming out of the exhaust? The booster fan doesn't look adequate to get airflow through one of those filters so at that point it is relying on the fart fan to pressurize the lower box. The air may blow around just fine when you have the door open but when closed, it's a different story.

Duct tape a bag over the exhaust and plug it in. You can calculate cfm pretty close and see what you are actually getting through the system.
 
TexMex McDirt

TexMex McDirt

Active member
My 2 cents on your ventilation issues. If you can find a way to cool tube your HPS bulb that would be a good start. Mainly tho, I don't think those duct booster type fans have any decent static pressure. They may be rated at 100 CFM, but without decent static pressure they are relatively weak and can't pull thru a filter well.
 
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wooderson420

Member
Thanks guys for all of your advice. I am out of town for a few days but when I get back I am going to try and resolve the issue. Not going to be a huge deal for another couple of weeks becuase my clones are pretty small still.

First two things I am going to do is add another in line fan to the vent between the two chambers, hopefully this will alleviate the hot air sticking around in the flower room. Then I am planning on getting a better fan for the out take/filter, and possibily relocate the filter outside the cab.

The DIY cool tube idea is great too--I had already been thinking of something along those lines b/c the cool tubes they have at the grow shop wont fit, and are 400w hps as opposed to 150.

If all else fails I can run T5s or LEDs downstairs, either I think - wouldnt heat up as much.

I really appreciate all the advice! I will let you know the results.
 
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wooderson420

Member
TexMex McDirt said:
My 2 cents on your ventilation issues. If you can find a way to cool tube your HPS bulb that would be a good start. Mainly tho, I don't think those duct booster type fans have any decent static pressure. They may be rated at 100 CFM, but without decent static pressure they are relatively weak and can't pull thru a filter well.
Click to expand...

Yeah I see 80 cfm or 100 cfm and I think, well this fridge is only 18 cubic feet, should do the trick. WRONG...haha.
 
FreezerBoy

FreezerBoy

Was blind but now IC Puckbunny in Training
Veteran
TexMex McDirt said:
Mainly tho, I don't think those duct booster type fans have any decent static pressure.
Click to expand...


Duct boosters are axial fans. Absent any restriction, they move more air than other types of fans. With static pressure or resistance, they become rather useless.
 
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wooderson420

Member
FreezerBoy said:
Duct boosters are axial fans. Absent any restriction, they move more air than other types of fans. With static pressure or resistance, they become rather useless.
Click to expand...

No joke? Ill keep that in mind. BTW FreezerBoy I admire you work, threads of yours inspired my project. :bow::bow:
 
touchofgrey

touchofgrey

Active member
wooderson420 said:
First two things I am going to do is add another in line fan to the vent between the two chambers, hopefully this will alleviate the hot air sticking around in the flower room. Then I am planning on getting a better fan for the out take/filter, and possibily relocate the filter outside the cab.
Click to expand...

As pointed out by Freezer Boy, the booster fans can't handle any static pressure so don't bother adding another. For a couple hundred watts you can easily make it work with one fan sucking on the filter. It just needs to be a strong fan.

If you read the literature for the store bought carbon filters they are rated at about .5 to .75 inches of static pressure. You will need a fan that would deliver about 75 cfm at 1 inch of pressure to draw through a passive intake, a vent between the chambers and the carbon filter. If you have the option to locate the filter outside that would save you space.

Read Ventilation 101 again to get a good understanding of static pressure and fan curves. I'm a firm beliver in the KISS method. Keep it simple and you will be able to get it fixed.
 
FreezerBoy

FreezerBoy

Was blind but now IC Puckbunny in Training
Veteran
wooderson420 said:
No joke? Ill keep that in mind. BTW FreezerBoy I admire you work, threads of yours inspired my project. :bow::bow:
Click to expand...

Thanks but, I've just been here longer and have more reading under my belt. As touchofgrey mentions, Ventilation 101 is a must read. Yes it will hurt your brain (hurts mine, anyway) but, it's good for you.

fancomp.JPG
 
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wooderson420

Member
Thanks Gents...

I am currently on vacation, looks like I have some homework to do before I get back! Didnt even know this ventilation thread existed otherwise Id have read it prior to assembly of my cab!
 
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