Passive Cooling Issue

[Techman]

Passive Cooling Question

Greeting all, and thank you in advance for any advice.

I live in a hot humid climate. In my large un-insulated garage I have a 16'x16'office with a window AC. This office, ceiling and walls, is insulated and dry walled. The floor is concrete slab. In this office I have built two side by side closets each with its own bookcase hidden door. Each room is 5x5x8'

Veg room has (4) t8 florescent (32w each x 4) and (1) 180w LED.

Flower Room has (1) 720w led (450w Draw), (1) large carbon filter w/460cfm fan w/6" ducting.

I am currently trying to passively cool these rooms by drawing cool air from the office (74-76 degree) into the veg room thru to the flower room into the carbon filter which exhausts back into the office. The intakes are opposite the filter/exhaust which is located as high as possible. I am running the fan at 1/2 speed. It seems that no matter how many fresh air returns, all 6" ducting, I can't seem to get the rooms below 82-84 when the lights are on.

Yes, I known, no fresh air enters the office at all, no co2 at this time. So.... I'm thinking of exhausting into the garage instead of into the office. If I exhaust air out, creating a vacuum effect, the air drawn in from outside will be 80-90 w/100% humidity. I would probably use a 4" fresh air inlet from the outside and let the rest draw thru on its own. The AC will obviously have to work harder.

I'm just wondering if anyone has any ideas or suggestions to help me get the 2 rooms below 80 degrees. I am currently running the lights at night but around here there is not a big drop
in temp or humidity. The two rooms run between 50-60 % humidity. I know bringing fresh air in is the right thing to do, just don't know how well it's going to work with the current AC. (6000btu), another idea is to draw back in from the garage instead of outside, the exhaust into the garage will act like an AC vent in there however I don't think it will cool the air that much since it's such a large un-insulated space. Well enough rambling, I'm leaving it up to the experts....

Thanks again

Techman

p.s. the plants don't seem to mind the temp as they are growing quite well, I just prefer to grow in a little cooler environment.

 

[Spimp]

Freeze some 2 liter bottles. Place them in front of your fan. Very ghetto and temporary solution but effective! I actually have ued it throughout my small micro run, but I dont mind moving them around andrefreezing them every night...

 

[Techman]

Thanks but looking for a more long term solution.

 

[Spimp]

Freeze 5 gal buckets?? Just kiddng, had to say it.
Is exhausting into the office also raising the office air temp creating a heating circle effect if you will?

 

[Techman]

Yes, the AC is set for 74 but thermo says 77. I hear the compressor kicking on/off so it does not run continuous.

 

[Spimp]

So let me see if I got it, Im buzzing so comprehesion is at a min right now.
AC>>office>>growbox>>into office? Have you ran it any other way? Seems like the exhaust going back into the office would drastically raise temps. Seems like the ac is fighting the exhaust air sir. But like I said, Im buzzing. Let me see if I can finda ya a link or two...
HOW TO DESIGN A FAN POWERED COOLING SYSTEM
HOW TO GROW MJ

First link is self explanatory. Second link has 100's of articles on growing, including 100's on grow room set ups and whatnot.

 

[Techman]

Thanks for the links. I'm contemplating other ways but like i said, the outside air is hotter and more humid than the exhaust back into the office. Perhaps dropping the office temp to 68-70 will help, however i really would like a little fresh air exchange.

 

[Graytail]

Where is the AC getting its air from? Is it merely circulating office air in a closed loop, or does it draw outside air? I guess it must be closed - should be. You sure don't want any of that hot humid air coming in - that'll just make it worse.

No, you've got it correct the way it is. You should be drawing return air from the cool dry office and returning it to the closed system. If you exhaust to the outside and create a vacuum, you'll just be bringing hot humid air into the loop. Dropping the office temp will get you the best result.

 

[Techman]

Yup, Closed Loop. I'm gonna add a fan and drop the room temp....

Side note: I forgot (lol) I do have a 3" bathroom type exhaust fan in the veg room ceiling running 5min on/off so I must be drawing "fresh" air in. Maybe I'll stop that and see what the temps run.