Cooling advice

[cj10488]

Ok I was wondering.. I have a pretty stable temp from 82 and hits a max of 84.. I have my heater set at 80.. I have 3 fans in my hood 2 exhaust and 1 intake and one fan blowing over the sump.. It still doesnt seem to be that effective at bringing the temps down anymore than 82 and 84 in the late late evening.. I have attached a pic of my setup as well.

Intake blowing into hood... Exhaust blowing out..


TIA,
James

 

[cj10488]

BTW 2 of the fans are 12v PC fans and 1 of them is a 120v fans.. I plan on mounting the fans at each end and one in the middle once I get the temp under control.. I have seen it hit almost 90 at the surface before when it was warmer outside.. Its pretty cool outside right now but I would like a permanent situation where i dont have to worry about it during the summer months either.. I was thinking about adding 2x 4" AC fans from radioshack to help but I think 5 fans is a bit extreme for just 2 halides and 2 pc lights 8-9" over the tank..

HTH,
James

 

[cj10488]

Ok so here is what I was thinking.. 2 80mm 4500rpm 12v fans 1 on each side blowing across the bulbs and 2 80mm 12v 4500rpm fans on the back of the hood blowing out for exhausting the hot air... or should I go with 2 120mm 12v fans 1 on each side and 2 80mm fans in the back of the hood for exhausting.. Does either of these sound sufficent to keep my lights from heating up my water??? I am kinda leaning towards the 2x120mm and 2x80mm whatcha all think

TIA,
James

 

[fishfreek]

I would have all the fans set to exhaust. The fans appear to be outleting behind the tank. Possibly trapping the warmer air back there and the net result is just circulating the air back there. If you can position the fans so they pull air in from the sides. Maybe adding some vent holes on the sides. Also adding vents in the top of the canopy will allow warm air to excape this way.

You appear to have good water flow at the surface in the main tank.

BTW are those fans held on with duct tape? If so I would seriously suggest a more stable mounting method. Would hate to have your tank short circit due to a failed bit of duct tape possiblyi causing fire.

 

[justDIY]

aaron nailed the big principals of cooling right on the head ... fans are for exhaust, convection vents in the top for hot air and unpowered vents to bring in fresh air.

if you're looking to upgrade fans, get the largest size with the lowest RPM you can accomidate in your canopy.

mount your fans on top if possible; hot air wants to rise, a fan will help it rise very quickly, or on the ends of the canopy. exhausting air right into a wall is going to create a lot of noise and reduce the effectiveness... so the side of the canopy with the most 'open space' around it is your best choice

 

[cj10488]

Yes they are held on with duct tape for the time being.. I pan to cut and mount into the canopy as soon as I find out where I want them. They are Extremely secure lol... What do you think about mounting 2 fans on each side 120mm and 80mm per side..


TIA,
James

 

[cj10488]

I am going to pick up 2 120mm fans later this afternoon.. I might take the hood off and cut into it later today or tomorrow (x-mas party and replace sis's motor in her car this weekend).. What I am thinking is putting the 2 120mm fans blowing in from the back of the tank and having 2 80mm fans 1 on each side mounted up as high as possible blowing the hot air out... Does that sound like it should work pretty good???

James

 

[justDIY]

when you blow air "into" a closed or confined space, you actually heat the air, not cool it... to test this, make a loose fist, cover your mouth with your thumb and forefinger while keeping a fist and blow into it - you will feel your hand become very warm... it's not because your breath is warm, it's because air is being compressed

additionally, fans blowing on something serve no purpose, unless it is something that can a) sweaat b) benefit from the psychological effects of feeling 'cool air'

house fans, air conditioners, etc, all take advantage of a human's ability to sweat and to feel the brush of the cool air ... but an inanimate object like a light bulb, would be better served by moving the air around it away, rather than forcing more air into the space around it.

by having all your fans blowing out, you create a low pressure enviroment... this will insure fresh air finds its way inside

also, lower pressure = cooler air ... the more air you get moving out from inside of the canopy, the cooler it will be inside the canopy, as the air left inside will expand to fill the gap (taking heat with it), and fresh cooler air from the room will also be rushing to get in there.

sorry if this sounds like a college lecture or something

 

[cj10488]

no that sounds absolutely awesome.. I will point both the 120mm fans and put them on the sides and hope that does the trick.. They are 1500-2300 rpm 12v.. I am going to remove the other fans and Temp mount them on the back and see if it causes the Temp to rise at all.. If not I will cut the sides tomorrow morning and mound the fans..

Thx Again,
James

Btw JustDiy Kudos

 

[cj10488]

Ok well I got the fans mounted today.. Everything looks awesome.. I mounted 2 120mm fans blowing out of the canopy 1 on each side.. I will find out how they work once the lights start to heat up some.. Thanks everyone for your help.. I am sure that the 2 120mm fans will provide plenty of cooling to my canopy..

Thx again,
James

 

[Electrobes]

coolness, I can;t wait to hear how it goes.. I am upgrading my lights soon (250 watt metal halide with two VHO's) on my 45G tall tank. I was planning on having two large fans in the back exhausting with the side of the hood having vents.

 

[micaheli]

Picking at an old wound

Well, I figured I'd bounce this extremely old post up - because I need help.

I'm DIYing a hood right now and would like to know what types of fans and where to place them BEFORE placing my orders.

So, the consensus seems to be that sucking air out of a space is preferable and really the ONLY way to do it. However, some may say that its best to have intake on one side, and exit on the other?

Now, to me that doesn't make sense - because one of the bulbs will be significantly warmer than the other one near the intake. The one near the exhaust will be warmer because it is recieving pre-heated air by the other bulb.

My plan was to encapsulate the whole hood fully (not to be anti circulation, but to create organized circulation) to the tank. With a leaning top, and 2 front doors. The back will have 2 intake holes.. driven by negative pressure, not by fans. And will have 2 fans on the side. My side fans will BOTH be blowing out. This way, each bulb has an intake and an exhaust and isn't recycling any airflow.

I have 2x 250watt halides pretty much on the way for a 55gal (pretty much the same setup as cj10488 except my hood will be slightly different.

I'm also curious as to how many fans I should get. I'll probably get 120mm fans as 80's just don't appear to be enough cooling power. I am thinking I'll get 4 of them.. 2 for the sides (blowing out) and 2 for the rear (assisting the intake of cool air).

Does this sound right to you? let me know


--Micah

 

[MadManMac]

One thing to remember, it is not the size of the fan, but the amount of air that it moves. There are many 80mm fans that far outperform the large 120mm fans. It is all about the amount of air that is moved, not the size of the blades. and yes, I am aware that this only applies to fans!

 

[Brad]

good one..

I did enjoy that one!

 

[micaheli]

See.. Thats what I thought.

I was going to go with 4 80mm fans.. Which HAD to move more air than 2 120mm's.. expecially high rpm, high CF/M fans.

--Micah

 

[micaheli]

So, I was doing a little more research on fans and such. I found some really nice temerature controlled 80mm fans that push 74cfm.. Most 120mm fans push 90-100cfm.

I'm thinking 2 80mm's on each side blowing out with a couple vents in the back allowing cool air in and keeping the internal pressure low. I think this should be about perfect.. but the only problem I for see is noise. They are 4800rpm fans.. those probably scream pretty good when they get going.... but I can put the sensor somewhere away from the bulb (120degrees F) is the max it needs to sense. And so it'll only go off during the summer and such for the full blown fan speed.. And at night, they'll switch off automatically when the hood temp goes down.

--Micah

 

[fishman]

Where did you find these and how much were they??

 

[micaheli]

These are dual ball bearing fans.. thermal sensor and manual speed settings as well.

They are 7 bucks from:

http://store.yahoo.com/kmexpress/ca-a1357.html

I plan on purchasing 4 of these unless I think of something else before I do so.

--Micah

 

[fishman]

link to product

I tried the link you posted and it does not work. can you repost the link or let me know the website you went to in order to order the fans for the tank? Thanks

 

[micaheli]

You probably tried just clicking the link. For some reason phpbb parses the URL incorrectly... so, copy and past the url into your browser.

--Micah