Aircon & exhaust fan

[greennoobie]

Hi all,

 

Just looking for some advice on the use of fan's with a 'portable split' air con.

 

The issue is, the exhaust fan ducts from a CF, through 2 cool tubes and then exhausts. Which is fine in most situations, until the A/C kicks in and most of the cooled air is lost through the exhaust, so the AC is almost always running to try an cool the ambient temp in the room.

 

Any ideas? Should the exhaust fan be stopped (and a seperate circuit for the cool tubes installed) or just slowed right down using a speed controller?

[Chato]

Hey GN

 

You could possibly cool the tubes direct from the portable a/c. Hard to say exactly in your case without seeing pics of your space but what i've done with them in the past is tape/seal two lengths of ducting to the portable a/c and run 1 into the room/space/tent and the other for the cool tubes or cooling rezzies.

 

Will depend how long your ducting is etc but maybe something to consider.

 

peace

c

[brick]

What temperature have you got the a/c set on?

 

if it is set for around 20-22oc then it would probably never cut out.

try it on a warmer setting. see what happens.

 

Have you got the outlet vents on the ac facing up or down. if up turn them down and it should force the cold air down and push the hot air up to the ct's.

 

try the different fan speed settings on the ac. low speed should be enough.

 

is it a refrigerated unit or evap cooler?

 

if evap cooler then ignore all of the above.

[The Hash Nibbler]

Hey green Noobie =), Yeah, not sure if ya growing in a room or a tent or what......... but got a rough answer for ya..........

You need to take the filter and fan off. Then make a seperate intake for your Cooltubes, can be in the air con room.

 

Buy a small inline computer style fan to run ya cooltubes and put it before them( make sure it can flow a decent amount). Most important..... You MUST dump that hot air exhausting from the lights OUT of the grow area or you will never get the Temps down. I take it your portable has a exhaust that goes out a window panel fitted to your window. Get a Y piece from a hydro store or air con mob, put it in between the air con and the window. Now you can vent the hot air directly outside and when the aircon is running it will not affect the grow area. Fan speed controller will probably be needed to switch down main room exhausting flow when you have aircon on(and remember to exhaust at the highest point of your area where heat gathers and then out through your carbon filter), and when your fine with ambient temps and not using aircon just crank up the flow again.

Hope this helps, all I can do seen as you have no info on your set up. Give us some more info and sure someone here will help ya out a bit better.

Gh72

 

Doh! Took me so long to type Chato and Brick beat me to it. .

Edited December 30, 2010 by Grasshopper72

[greennoobie]

thanks for the quick replies!

 

Chato - using the ac to cool the tubes down is a no go, the AC isnt a tradional portable - it has a seperate condensor and compressor. Thus using it to cool the lights will result in the unfiltered room air being pumped out the room.

 

Due to the situation of the room, the A/C is fighting all sorts of environmental issues. The room is (very) well insulated with aircell outer, R3 batts and then 20mm MDF with another layer of aircell on the inside (but thats more for light reflection than insulation, tho it does both.

 

The environmental issue is that the room itself is in a shed, which given current air temps gets hot (hense the attention to insulation) with the hotside of the a/c being in the open shed (which has air flow through vents in the side wall of the shed plus a whirlie bird) - but none the less the temps on the hot side of the shed get right up there!

 

The room itself is 4mx1.5m (.8 x 1.5 mother room, the rest flowering), with air being drawn and expelled at opposite ends of the long side.

 

Brick - I think the above post clarifies the type of AC! It is refrigative. Its been set to 25 = 26 deg, today, with a current temp of 32deg, it is getting down to 26 to 27, just short of the desired temps - which is why I am wondering if it is better to setup a second air circuit for the cool tubes that runs full time and then have the filtered air come on for say 10m an hour to exchange the air, or if just slowing down the existing fan that does both light cooling and air exchange is the better option. Having said that, over the last few days of 40 ish temps, room temps did not get over 32deg - which isnt too bad in my (humble) opinion.

 

I *think* the issue I am facing, given the environmental issues I face regarding temp, is that the cooled air from the AC is being drawn out of the room too quickly to have a good effect.

 

Again, thanks for the replies. Having joined a few different boards, I have learned lot just by reading. I have never really over come the potential security issue of posting online - but too late now! Plus I need help, that I just havent been able to resolve myself by trial and error or research.

 

Cheers,

GN.

 

Edit - grassgopper - same issue! I think the above post might help answer your questions. But is sounds from your post that the best solution is both, a circuit for the tubes and another for the room itself. Regarding speed controllers, I have been toying with the idea for a while, however the issue that concerns me is there are some ppl saying they can stuff up the fan (I have a centrip main fan [150mm) - cant remember the brand, and it is well and truly boxed up for noise)

Edited December 30, 2010 by greennoobie

[greennoobie]

hopefully this works....

 

an example of the type of AC I am using is:

http://t2.gstatic.com/images?q=tbn:ANd9GcTi4TQHqsHnhEYjFcJAhZeB8jtz1QF8Rsym0vPfiFI9Fi2Coc7hMQ

 

it is a 'split system'. however both units are movable and perminantly joined by refrigerant hose (fixed)

[The Hash Nibbler]

Hey GN, mate to be hionest if your only getting a few 40's days and the temps only get to 32 in the room, why bother fixing it? Not so bad. A little ventilation tweak with the fan speed controller might be enough to see you through summer. just remember put a bucket of water in there if the humidity goes a bit too low. Soz man, saw you said split and portable air conditioner , and had to go with one. . Sheds and shitty fibro rooms like mine always going to battle the heat in summer.........even with air con........I'm shutting mine down. .

She'll be apples mate Gh72.

Edited December 30, 2010 by Grasshopper72

[greennoobie]

why bother fixing it? I am a perfectionist! .

 

on a serious note tho, its the first of many days like that of summer. And my greater concern is the AC being on full cycle already. Also, having adequate air exchange in the room if I slow down the fan / run it periodically every hour.

[Chato]

Hmm i'm a bit smashed today and mental imagery not runnin at full speed.

 

But using the same air in the room albeit a/c'd to cool the lights is not ideal in the first place imo.

 

1 idea i'd try is running ducting off the a/c straight thru the cool tubes with no exhaust. In other words just hook up the 2 tubes with a/c'd air coming in but no ducting coming off the 2nd coolie. I think you'll be quite surprised at how cool the air still is even after going over 2 bulbs (1000w's might stretch the friendship) Then have your normal exhaust runnin thru a filter and out....

 

As is said in earlier post and from looking at your pic you can run 2 lengths of ducting from your a/c unit.

 

 

One to the the coolies and one close to the floor of the room.

 

Just throwing it out there

 

peace

c

[Chato]

Hmm after shower and another cuppa i realised that answer might not be what your looking for if you want to avoid running the a/c all the time.

 

But maybe worth a shot and cooler the lights closer ya can get em to the plants yada yada yada

 

Best of luck.

 

peace

c