cliffrouse11bas
Active Member
I am mounting two 3 in fans in my diy canopy I was wandering how I should have them blowing. I am thinking one in and one out....
Fans?
- Thread starter cliffrouse11bas
- Start date
rsd
Member
I know alot of people disagree with me but I have been building racks where we measure the air output and cooling rates of high temp gear for over 4 years. The ONLY way to maximize the use of the fans is to have both fans push air into the canopy. Unless you canopy is air tight having one push and one pull will generate cavatations and "jet streams" instead of refreshing the entire air stock with cooler air. Also I would recomment you leav a 1/4 inch space between the canopy and the fan to allow you to place in a fiber filter to remove airborne debris like cat hair, cig. smoke, dust, pollen, etc.
If you push the air over the water you will improve evaporation and thus cooling abilities. Water evaporation is an extremely efficiant way to reduce temperature; thats why we sweat... however it means you have to replace water more often
If you push the air across your lights it keeps your lights cool which will help keep your aquarium cool. You will notice the air escaping from the hood to be very warm.
Why both fans pushing?
Say the fans push 100 cubic feet per minute. 2 fans = 200 cfm. that means that 200 cfm has to leave from under the canopy. If 1 fan pushes while 1 fan pulls that means the only 100 cfm has to leave the canopy. The air will begin to form a highway between the 2 fans. Yes some of the fresh air will remain in the canopy... but you'll be looking at about a 60% rating.
If both fans push into the canopy you'll see closer to a 88% rating. We figured this over many many tests with racks of gear that creates alot of heat. I know that when the polarity is off on one dc fan and it is pulling instead of pushing (most of my racks have 2-3 fans) my temp light will begin to indicate an over heat... when all fans push into the system I see nothing but happy gear.
It's all physics... just try it out. And when its all said and done you will decide what you like best and do that. No one system is the absolute. this is just what my experience has shown
Good luck and sorry for rambling so long!
If you push the air over the water you will improve evaporation and thus cooling abilities. Water evaporation is an extremely efficiant way to reduce temperature; thats why we sweat... however it means you have to replace water more often
If you push the air across your lights it keeps your lights cool which will help keep your aquarium cool. You will notice the air escaping from the hood to be very warm.
Why both fans pushing?
Say the fans push 100 cubic feet per minute. 2 fans = 200 cfm. that means that 200 cfm has to leave from under the canopy. If 1 fan pushes while 1 fan pulls that means the only 100 cfm has to leave the canopy. The air will begin to form a highway between the 2 fans. Yes some of the fresh air will remain in the canopy... but you'll be looking at about a 60% rating.
If both fans push into the canopy you'll see closer to a 88% rating. We figured this over many many tests with racks of gear that creates alot of heat. I know that when the polarity is off on one dc fan and it is pulling instead of pushing (most of my racks have 2-3 fans) my temp light will begin to indicate an over heat... when all fans push into the system I see nothing but happy gear.
It's all physics... just try it out. And when its all said and done you will decide what you like best and do that. No one system is the absolute. this is just what my experience has shown
Good luck and sorry for rambling so long!
cliffrouse11bas
Active Member
I paid 14 a piece for mine...
cliffrouse11bas
Active Member
Radio Shack I hooked them up and they ran quiet in my opinion. They are 3 inch computer fans 12v ran by a 500a adapter....