Cooling 8 Gavitas without an a/c? How realistic?

[Epiphyte]

Hello,
I'm in relatively cool environment. I am trying to cool 8 750w gavitas without a/c.. The room is basically 10x20x8h. I was thinking about having 2 10in wind king 750cfm fans attached to carbon filters Y together in the middle of the room and then go into 8inch duct which has an extra 8inch inline fan, 730cfm, as a boost at the end. I need two fans because for smell reasons, if one fails, I need a backup carbon filter. Also the veg 8inch exhaust will connect the the flower exhaust duct around where the final 8inch fan is. I was planning on having another 8inch inline fan as an intake. Do yall think this is sufficient to cool a room this size? And since it has constant air circulation, is there a chance that I don't need a dehumidifier? This is in the bay area. Please let me know what you think! Thanks
Epiphyte

 

[DONAJTHEIII]

Hello,
I'm in relatively cool environment. I am trying to cool 8 750w gavitas without a/c.. The room is basically 10x20x8h. I was thinking about having 2 10in wind king 750cfm fans attached to carbon filters Y together in the middle of the room and then go into 8inch duct which has an extra 8inch inline fan, 730cfm, as a boost at the end. I need two fans because for smell reasons, if one fails, I need a backup carbon filter. Also the veg 8inch exhaust will connect the the flower exhaust duct around where the final 8inch fan is. I was planning on having another 8inch inline fan as an intake. Do yall think this is sufficient to cool a room this size? And since it has constant air circulation, is there a chance that I don't need a dehumidifier? This is in the bay area. Please let me know what you think! Thanks
Epiphyte

Im going to have to say no on this one sadly.....even with the cold temps right now.


You need bigger vortex fans like 2 14" to exhaust hot air and use a passive intake. then I think you might be able too keep it in the high 70's low 80's. I helped set my homies 5k room up and I told him to grab 2 12"s and it keeps it around 78-80.

just my exp. guessing the extra 1k would be easily handled with the extra 4 inches from both fans.

Also you should like the extra humidity right now


AJAE

 

[mowood3479]

In the winter probably ya, u may need to buy another 12" worst case but in summer I'd say prob not... Night time isn't long enough in the summer..

 

[DONAJTHEIII]

Ahhh FYI i always like to go bigger on my fans because you can plug in a 20-30 buck speed controller and dial it down to your liking to really get a dialed environment in


AJAE

 

[fishwhistle]

I have 8 750s in a 12x12x8 room(this is how many gavitas lighting plan called for in my space BTW)i use a 2.5 ton mitsu heat pump minisplit for cooling and i cant imagine doing it with intake/exhaust especially in summer or warm days.

 

[Jbuzz]

if it's cold outside (55 degrees or less) and you have a 1000cfm intake, proper air flow inside the room, this is very realistic to cool. you will be best suited to run your light period at night for coldest intake temps possible. I have used 500cfm to cool 4 1000w DE ballast/bulbs in a 11x13x9 room.
if your outdoor temps get warmer than that, you will need A/C, no getting around that.

 

[Allendawg]

Look up Heath Robinsons thread it was about vert tree growing its a great way to start.(depending where you live) But I prefer fish whistles set up! I use bare bulbs & gravitas cool with mitsu minis, dehumidier Santa Fe.

 

[spunion]

I have 8 750s in a 12x12x8 room(this is how many gavitas lighting plan called for in my space BTW)i use a 2.5 ton mitsu heat pump minisplit for cooling and i cant imagine doing it with intake/exhaust especially in summer or warm days.

I've never heard of those before. Just looked up them, seems a lot more convenient than using window or portable A/C units that require exhaust.

Apparently you may be eligible for rebates by purchasing one:
http://www.dsireusa.org/

 

[Snype]

In the winter time it shouldn't be a problem at all. I cool 4k rooms by bringing in nighttime winter air into the room with 2 x 4" inlines and insulated dryer ducts. I keep my rooms at 72 degrees and the inlines have to shut off via a Titan Zepher 1 or the room will get too cold. If you set up the vents right, you should be able to cool the room with 2 x 6" inlines bringing in cold winter air at night. Dehumidifier will keep the room warm during the day. You will surly need one.

 

[TheSilverMullet]

I'm running 8 1150 watt gavita E series in a 12W x 20L x 10H room on the Oregon coast with one 12" max fan (1708 CFM) exhaust and three 12" passive intakes. This is my flowering room so it the lights run at night and I've had no problem keeping canopy temps under 78F with this setup so far. On the colder nights the fan only clicks on every few mins for and runs for a min. or two before clicking off again.

I will obviously have to dial the lights down and/or get some AC going for the summer but for now the room is doing great and having no issues staying at ideal temps.

To answer the OP though you will probably be cutting it close with those smaller fans and low ceilings. I also think you will want a dehumidifier to run from week 4-5 on wards. You could always dial the lights down a bit if you're having trouble keeping it cool enough.

 

[pankynugga]

Hey Silver Mullet, I know this been asked a hundred times, but are the yields noticeably bigger?

 

[TheSilverMullet]

This is my first round with these lights so I cannot yet speak on yields but I will say that I've never seen this cut of platinum GSC be as fat, frosty and tightly stacked at week 4 and I've been running this clone for over a year now.

I am expecting a bump in yields and quality just based on how things are looking now.

That said I've got plenty of time to screw things up haha.

 

[JointOperation]

in the winter my dehumidifier dont need to be on with outdoor air cooling the room.. mainly need to add humidity .. especially using cold outdoor air thats usually super dry.. i need to use a humidfier.. just had to buy one.

 

[Snype]

in the winter my dehumidifier dont need to be on with outdoor air cooling the room.. mainly need to add humidity .. especially using cold outdoor air thats usually super dry.. i need to use a humidfier.. just had to buy one.

Same here for me as well but once your lights turn off, your rH will skyrocket from the plants transpiring. My humidity is fine as long as that cold winter air is coming into the room but once the lights turn off, my rH goes to 99% so that's when my dehumidifier kicks in. I surely don't want to bring in any winter air when the lights go out or it will be freezing in the room. The dehumidifier also helps the plants get some heat in the dark cycle which helps greatly for me.

 

[TheSilverMullet]

Snype do you have zero fresh air coming into your room during lights out?

I've been trying to have enough heat generation going on in the room between a couple dehumidifiers and a heater during the dark period so that my thermostat will kick the exhaust fan occasionally and refresh the air because it seems like the plants would like that fresh air.

But if it's not needed I then I guess it's kind of just a waste of power.

 

[Snype]

Snype do you have zero fresh air coming into your room during lights out?

I've been trying to have enough heat generation going on in the room between a couple dehumidifiers and a heater during the dark period so that my thermostat will kick the exhaust fan occasionally and refresh the air because it seems like the plants would like that fresh air.

But if it's not needed I then I guess it's kind of just a waste of power.

I don't have any fresh air that comes in at night. Plants don't need CO2 in the night cycle. I run fans in the room that are on 24/7. They just circulate the air in the room. My 50 Pint Dehumidifier keeps the room 59 degrees F on the coldest days. This room only has 4,000 watts and is 8.5' x 11'. The coldest days outside temps is -6 but on average it is in the teens at night.

 

[TheSilverMullet]

Cool thanks for the response Snype

 

[Epiphyte]

Thanks for all the responses!

TheSilverMullet- Can you explain how your passive intake is set up? Are the holes next to each other, is there any filter, would a fan help or hurt etc.
Thanks so much

And I think I am going to have two 12" fans with carbon filters and speed controllers. I need the buffer and I'll probably have one kick off at night and one will stay on for cleaning reasons. But I'm not sure about the intake. Would a 4 or 6 inch fan with a hepa filter be better than 2 or 3 passive intakes and do those passive intake need to be 12 inches?
Epiphyte

 

[TheSilverMullet]

I had to run 12" ducting through another room to the north side of the building so I could pull air from the shaded, cooler side. I did some bends in the ducting to prevent light from coming in. I don't have any filters, just hoods and screens on the outside to prevent bugs and whatnot from getting sucked in.

I plan on adding an active intake after this round maybe just an 8" max fan since I already have a couple. I'd rather have the air flow and not need it than be battling heat issues mid flower with no other option but to turn the lights down.

If you have 2 12"s you will for sure need a lot of passive intake area or a good amount of active intake as well. Honestly with just those two passive intakes that I have there is still a lot of negative pressure, probably more than I would like. I think it puts strain on the fans to have too much but you definitely want some negative pressure if you are worried about smells. There are some good threads on the subject that were helpful to me but honestly I end up just kind of trial and erroring my way through most of this stuff.

One thing to note if you go 12" fans- they can be loud! I can only speak for the 12" max fan but the thing is like a jet engine I had to get a silencer but even with that it's still pretty noticeable.

In hind sight I perhaps should have gone with the 14" max fan because they move about the same amount of air but they run at lower RPM so they are quieter and use less power.

 

[JointOperation]

im cooling a 10x10 with 4000w .. with 2 6 inch ho can fans.. and 1 4 inch booster intake from outside air.. and another 6in booster intake from the lung room.. and my room stays at 78-80. and on cold nights like lastnight. if i played with the controller i could of got the room down to 60 degrees prolly.. I should say. not gavitas by the way.. there are reg bulbs.. and as I understand gavitas run a little hotter.. so a better intake would be needed to cool the room down