Direction of canopy fans?

[grouper therapy]

Jgoal55;493155 wrote: lol....yeah.....the less I have to do the better.....


so its settled....all fans in.....exhaust holes drilled in the top.....

How many? how large? Thinking of just drilling with hole saws as that would be easier than using the jigsaw.....I believe I have a 2in hole saw would four holes on each corner be enough?

Be ready for some lighting maintenance!

 

[jgoal55]

you mean as far as cleaning the bulbs and the reflectors every once in a while????

come to think of it....my reflectors don't have any shields....they are SE bulbs so I had it understood that they are not necessary but should I get some anyway to protect the bulbs? I imagine it would also keep the reflectors clean?????

 

[grouper therapy]

Jgoal55;493163 wrote: you mean as far as cleaning the bulbs and the reflectors every once in a while????

come to think of it....my reflectors don't have any shields....they are SE bulbs so I had it understood that they are not necessary but should I get some anyway to protect the bulbs? I imagine it would also keep the reflectors clean?????

Jorge I don't mean to over think this I just wanted you to be aware of the most efficient heat removal method that has been around 50 years and that there are draw backs to it as well when salty air is involved but in my opinion not as many drawbacks as blowing that same salty air all over my lighting whether it be inside the reflector or outside the reflector. The salt creep seems to be worse as well on the sides of the canopy when the air is blown in across the water. I like to pull the hot air out since it is a proven efficient method and to concentrate the salt accumulation to the fans mainly, just my way. I think the shields will help but you are going to have to clean the inside or the canopy anyway.

 

[grouper therapy]

I am sure some will state that they don't have issues with salt when they blow the air in but the same system would not have it pulling the same air out either.

 

[jgoal55]

no i got you...i appreciate the other point of view. Im gonna give it a shot this way and I can always change it if it doesnt work well.

So how big should the vent holes be?

 

[jgoal55]

I dont think they make covers for my reflectors...at least I havent found them on Google... anyone know?

 

[skriz]

grouper therapy;493110 wrote: A fan placed at the highest point in the canopy blowing out is the most efficient method of heat removal. That is why for several decades now exhaust vents in attics on houses have been pulling hot air out ,not pushing it out. As stated earlier hot air rises and a fan in the top would remove a more concentrated heated air than a fan blowing in mixing the cooler with the hot and trying to force it out of the canopy. I guess you could mount a squirrel cage fan blowing 600 cfm at the end and push enough air in the canopy to remove all the heat but why do so?

GT is right if you are simply trying to remove warm air from the canopy. BUT, you only want to go in one direction (not one in and one out); either push or pull.

I assumed you were using the fans assist in evaporation also, in which case, you'll want to push air in.

 

[grouper therapy]

Skriz;493394 wrote: GT is right if you are simply trying to remove warm air from the canopy. BUT, you only want to go in one direction (not one in and one out); either push or pull.

I assumed you were using the fans assist in evaporation also, in which case, you'll want to push air in.

+1 I agree 100% all one way or the other so you get the most cfms for the fans running,

 

[tony_caliente]

Good thing this was a simple question. I am at 82 degrees and have central A/C. I would buy some stick fans too and blow them around the tank. Air is cooled when it moves. That's what I am doing.

 

[hellfire]

I apologize as I didn't read the entire thread, but just as air would find its way out, it will also find its way in.

So in the 2x 30cfm example, you would still have 60cfm of air movement either way.

Tyler

 

[grouper therapy]

Hellfire;493528 wrote: I apologize as I didn't read the entire thread, but just as air would find its way out, it will also find its way in.

So in the 2x 30cfm example, you would still have 60cfm of air movement either way.

Tyler

Correct.

 

[grouper therapy]

The problem with blowing air in is that you are mixing the hot air at the top of the canopy with the cooler air at the waters surface thereby increasing the air temp at the waters surface. The hot air and cold air naturally separate in the hood why mix it back and try to force it out even with the exhaust ports. Natures own heat exchanger. Makes no sense to undo something that is benefiting you in terms of cooling the water.. If you want to evaporate water I would do that in the sump away from my lights. In my experience there is very little salt creep in fans pulling out if there are no fans blowing across the surface to cause more evaporation.

 

[grouper therapy]

ares;493740 wrote: if the ventilation is adequate the temp difference in such a small area with so much air movement should not be significant.

You are 100 and 10% correct. Thank you for saying better than I

 

[jgoal55]

ok....all IN they went.....and here is what I noticed....

W/ out lights the tank was running at a steady 77-78. Yesterday the lights were on for 2hrs w/out fans and the temp went up to 80.6. I turned the fans on and when I checked 4hrs later the temp was at 79.2 so thats not too bad. I'm probably going to put one more fan over my sump to aid with more evaporative cooling. I think with the sump fan, I'll avoid needing a chiller.

Thanks for the help guys....so far, so good.....

 

[hellfire]

If its easy to switch your direction, you should run it one way for a week, then the other and let us know which one worked better.

Tyler

 

[grouper therapy]

ares;493566 wrote: fans are like pumps. if you wanted to move lots of water, you wouldnt put 2 pumps in series, you could put them side by side. 1 pulling 1 pushing is redundant, and since we arent really concerned with backpressure, wasted.

blowing in will save fans, and generally allows you to direct air flow across the water surface, vs pulling air out, where the air flow will be more spread out and may route over the surface of the tank all together to some extent.

Really not the same thing
This is only true if the canopy was a pressurized chamber. With adequate ventilation or openings fans blowing in, out or both will not effect the amount of air being recirculated since it become a closed loop with the room. If you were to seal the canopy air tight and have only two openings one being the fan in and the other being the fan out then you would only move the cfms of one fan. I agree with the all the fans in one direction from the purpose of the fans direct heat removal or evaporative removal.

 

[grouper therapy]

ares;493566 wrote: fans are like pumps. if you wanted to move lots of water, you wouldnt put 2 pumps in series, you could put them side by side. 1 pulling 1 pushing is redundant, and since we arent really concerned with backpressure, wasted.

blowing in will save fans, and generally allows you to direct air flow across the water surface, vs pulling air out, where the air flow will be more spread out and may route over the surface of the tank all together to some extent.

This is only true if the canopy was a pressurized chamber. With adequate ventilation or openings fans blowing in, out or both will not effect the amount of air being recirculated since it become a closed loop with the room. If you were to seal the canopy air tight and have only two openings one being the fan in and the other being the fan out then you would only move the cfms of one fan. I agree with the all the fans in one direction from the purpose of the fans direct heat removal or evaporative removal.

 

[jgoal55]

Tyler...definitely not easy enough.

im gonna hook up my controller this weekend so ill have a better idea of what the temp is doing...ill keep you guys posted.