Temperature Control

i have got a grow room, with 2 cool air intakes which are about 1 foot off the ground and then an extractor near the light the room is appoxamently 5 foot by8 foot and 6 foot tall, the temperature is 30 degrees at the bottom but near 40 degrees at the top what can i do do balance the temperature out..

 

You might want to try an oscillating fan to blow everything around to allow the air to mix a bit.

 

i have got an 8" oscillating fan on 1 of the air intakes blowing to the middle of the room and the other air intake blowing to the ground..

 

It sounds like you need a bigger volume extractor, or else an externally vented cool tube/vented reflector set up. What are the sizes of your intakes and extractor ducts?

 

2 6" cool air intakes from outside and an 8" extractor about 6" away from the bulb..

 

I am thinking that with those temps a small AC might be called for. 40'C is pretty hot.

 

my m8t said about getting a AC but i dont want to spend out to much until this crop is done so i can expand my room and by better equipment..

 

Are you using air cooled hoods or cooltubes for the lamps? Those make all the difference in the world, and aren't that expensive (a couple hundred maybe, but very worth the price.)

 

Your exhaust port (the 8" hole at the top, by the light) should have an extractor fan in it, forcing the hot air out. If you're using all passive ventilation the hot air isn't exiting fast enough, it's just backing up and making the whole room warmer.
If you are running a powered exhaust and passive intakes, you want at least three or four times the amount of intake area you are using. Two 6" round holes roughly equals one 8" round hole in area. A passive intake should have at least 3 or 4 times (even 5 times is not too much) the area of a powered exhaust. So, if you already have a powered exhaust - quadrupling the intake area should speed up the ventilation air flow and cool things down.

 

the 8" has got quite a powerfull suction on it but at the moment it is just blowing into the loft it is not extracted to outside yet i am waiting on a carbon filter to arrive then it is going to be ported into the chimey breast. and what would you say the best temperature is because i had my old setup running at 27 - 30 and all went fine till i got busted

 

Would placing dry ice in the room help lower the temperature? If so, how often would it need to be replaced?

 

I think that with the temps in his room that there would be a nice fog. The plants could use the co2 though

An AC is the way to go.

 

cheers went and got one to day cost £200 but money well spent (i hope)

 

But, can dry ice be used to lower the temperature?

 

My hoods are vented...by force...and I have CO2 with propane but the recent heat wave has forced me to buy an a/c. Problem is, if you vent from outside to the a/c the CO2 meter picks up the dilution and turns on the gas...thereby raising the heat again...and ruins the effect. So tomorrow I'm going to install the a/c IN the grow room without venting it. Just looping the air around might help. We'll see.

Any growers out there with a/c experience that also use sophisticated controls for the heat/co2/lights, etc.?

TKS

 

PS...dry ice goes away almost instantly. CO2 injection by tanks would cool and be cheaper.

 

Three days later...and the a/c did NOT work by having it IN the room...so I cut thru the styrofoam walls and now have it venting outside but circulating inside...(a setting on the front).
Don't think it's having enough effect. Outside air is just too warm for hood vents and re-freshing air from climate controller.

So now I'm going to post to get opinions on co2 gas (tank, not propane burner) to inject co2 in the summer months.

Look for post on co2: gas burner vs. tank injection

 

Most people who use air conditioners place them too high in the room.
You only need them to keep the root area cool so place the AC on the floor and direct the air to the root area.
Directing the air and keeping it low in the room by placing some type of roof about 2 feet off the floor works really well, it works even in a 20' x 8' room.
All the cold air is around the roots, just make sure it doesn't get too cold but it doesn't take much to work out a timing system so the temperature stays constant.

It doesn't matter how hot it gets above the root system, within reason of course, in fact 22/28 degrees around the roots and 30/40 degrees above and they thrive.
You don't need a huge extractor fan doing it this way. A small one is fine as the cold air forces the hot air up and out anyway.

If you use plastic boxes with the mixture in the bottom and another box on top filled with grow wool you won't have any problems at all.