Experience with exhaust fans

Reefstarter2 · 02/07/2016, 02:26 PM

I am trying to figure out if I add to fans pulling air from my canopy to the outside will be enough to keep the chiller from coming on . in summer with AC running . I don't have central but I might go with the hang on wall type soon . I forget the name of them . So I am running 3 250 watt radiums and a pair of 80 watt T5 over a 210 with a canopy that is roughly 16inches tall and has to fans pushing air in with 3 4 inch holes at the top to vent heat . I though this would be enough ,. But,..... the temp hit 60 here and my chiller came on . so I was considering changing lights . This is a good excuse lol. but trying not to since I love halides . Has anyone done what I am thinking about and has it worked ? Thanks inadvance

happy reefing

TimeConsumer · 02/07/2016, 02:38 PM

I'm going to draw on my experience with computer air cooling here:

Up to a certain point, more airflow is a good thing. Beyond that point it can be either good or bad, depending on the setup. If the additional fans do no more than add turbulence, they aren't really helping. If the additional fans are arranged in such a way that they increase the flow while still maintaining a smooth flow without much turbulence, they are helping.

Now in your case two, 4" fans (120mm computer fans would be my guess) is pretty small for 900w of heat. I have 6, 120mm fans cooling my desktop computer that pulls less than 400w under full load.

I think you should try to add in both more intake and exhaust fans. Then we can also start getting into issues of positive pressure vs negative pressure, but I think that's rather moot when we're talking about a 6ft canopy.

Finally, consider pointing some fans directly at the waters surface of either your display or sump, these will increase evaporative cooling significantly.

kenneth wolfe · 02/07/2016, 02:47 PM

temp hit 60? I have a 8" high speed fan in my canopy with no vents , it just pushes threw the cracks and my rear overflow, It is a real noisy fan but moves a lot of air. it works better at dropping temp than my chiller. I use it in the last line of devises to control heat. I also have a fan on the fuge, and extra on chiller that comes on separately from the chiller, and also a fan that brings fresh air into bottom of stand.. Fans work great but use a lot of water for evaporation . I turn on chiller first to help save with the evaporation.I sounds like you need to move more air in the canopy " buy some real fans"..

Reefstarter2 · 02/07/2016, 03:38 PM

These are not computer fans they are Icecap smart fans . The fans I will use to pull air outside will be something that mounts outside with 4 inch flex coming from the top of canopy .

ca1ore · 02/07/2016, 04:01 PM

With the current arrangement, is the air inside the canopy noticeably warm? If it is, then adding some canopy ventilation will help; if its not, it wont. Keep in mind that much of the heat added to the tank from halides is from infra-red light, not convection.

TimeConsumer · 02/07/2016, 04:02 PM

Yeah, those icecap smart fans are basically computer fans except with an AC adapter and a thermistor. The OEM is probably yate loon or one of the other big fan manufacturers, probably a sleeve bearing too which means don't mount them horizontally, otherwise half the shaft won't get lubricated.

I would either move to a big air duct booster fan (can fan) or stick with computer fans except get really nice ones like some 140mm Noctuas, you can cut the 3-pin adaptor and just hook it up to an old 9v or 12v AC adapter. You can easily run 6 fans off one 12v 500mA adapter.

And what is said above is important too, ambient air temperature is huge. You can't go below ambient.

Reefstarter2 · 02/07/2016, 05:10 PM

now we are getting somewhere . looks like a light change is in the near future , don't know if I should smile or frown lol.

02/07/2016, 02:26 PM	#1
Reefstarter2 Registered Member Join Date: Aug 2014 Posts: 295	Experience with exhaust fans I am trying to figure out if I add to fans pulling air from my canopy to the outside will be enough to keep the chiller from coming on . in summer with AC running . I don't have central but I might go with the hang on wall type soon . I forget the name of them . So I am running 3 250 watt radiums and a pair of 80 watt T5 over a 210 with a canopy that is roughly 16inches tall and has to fans pushing air in with 3 4 inch holes at the top to vent heat . I though this would be enough ,. But,..... the temp hit 60 here and my chiller came on . so I was considering changing lights . This is a good excuse lol. but trying not to since I love halides . Has anyone done what I am thinking about and has it worked ? Thanks inadvance happy reefing

02/07/2016, 02:38 PM	#2
TimeConsumer Registered Member Join Date: May 2011 Location: New Orleans, La Posts: 1,919	I'm going to draw on my experience with computer air cooling here: Up to a certain point, more airflow is a good thing. Beyond that point it can be either good or bad, depending on the setup. If the additional fans do no more than add turbulence, they aren't really helping. If the additional fans are arranged in such a way that they increase the flow while still maintaining a smooth flow without much turbulence, they are helping. Now in your case two, 4" fans (120mm computer fans would be my guess) is pretty small for 900w of heat. I have 6, 120mm fans cooling my desktop computer that pulls less than 400w under full load. I think you should try to add in both more intake and exhaust fans. Then we can also start getting into issues of positive pressure vs negative pressure, but I think that's rather moot when we're talking about a 6ft canopy. Finally, consider pointing some fans directly at the waters surface of either your display or sump, these will increase evaporative cooling significantly. __________________ Steve - Retired from reefing, for now.

02/07/2016, 04:01 PM	#5
ca1ore Grizzled & Cynical Join Date: Apr 2006 Location: Stamford, CT Posts: 17,319	With the current arrangement, is the air inside the canopy noticeably warm? If it is, then adding some canopy ventilation will help; if its not, it wont. Keep in mind that much of the heat added to the tank from halides is from infra-red light, not convection. __________________ Simon Got back into the hobby ..... planned to keep it simple ..... yeah, right ..... clearly I need a new plan! Pet peeve: anemones host clowns; clowns do not host anemones! Current Tank Info: 450 Reef; 120 refugium; 60 Frag Tank, 30 Introduction tank; multiple QTs

02/07/2016, 04:02 PM	#6
TimeConsumer Registered Member Join Date: May 2011 Location: New Orleans, La Posts: 1,919	Yeah, those icecap smart fans are basically computer fans except with an AC adapter and a thermistor. The OEM is probably yate loon or one of the other big fan manufacturers, probably a sleeve bearing too which means don't mount them horizontally, otherwise half the shaft won't get lubricated. I would either move to a big air duct booster fan (can fan) or stick with computer fans except get really nice ones like some 140mm Noctuas, you can cut the 3-pin adaptor and just hook it up to an old 9v or 12v AC adapter. You can easily run 6 fans off one 12v 500mA adapter. And what is said above is important too, ambient air temperature is huge. You can't go below ambient. __________________ Steve - Retired from reefing, for now.

02/07/2016, 02:47 PM	#3
kenneth wolfe Moved On Join Date: Aug 2014 Location: Galveston Co. Posts: 853	temp hit 60? I have a 8" high speed fan in my canopy with no vents , it just pushes threw the cracks and my rear overflow, It is a real noisy fan but moves a lot of air. it works better at dropping temp than my chiller. I use it in the last line of devises to control heat. I also have a fan on the fuge, and extra on chiller that comes on separately from the chiller, and also a fan that brings fresh air into bottom of stand.. Fans work great but use a lot of water for evaporation . I turn on chiller first to help save with the evaporation.I sounds like you need to move more air in the canopy " buy some real fans"..

02/07/2016, 03:38 PM	#4
Reefstarter2 Registered Member Join Date: Aug 2014 Posts: 295	These are not computer fans they are Icecap smart fans . The fans I will use to pull air outside will be something that mounts outside with 4 inch flex coming from the top of canopy .

02/07/2016, 05:10 PM	#7
Reefstarter2 Registered Member Join Date: Aug 2014 Posts: 295	now we are getting somewhere . looks like a light change is in the near future , don't know if I should smile or frown lol.