Computer geeks ... fan question... ducting/CFM

[Tanner]

Since I'm re-working the box for my amp rack, I figured I'd better think long and hard here about my fan situation. I'm down to 4 fans now... but my question/dilemma is this.... Two of my amps have been getting REALLY REALLY hot. I've added a second run of 0 guage wire which should help some... but not totally. Since this amp rack will be sealed it definately has to have fans. I was originally going to put 3 fans blowing on the amps and one sucking. I wanted to have the 3 blowing lengthwise down the heat sinks on the two Hot amps. I figured I'd get a vacuum effect which would force the additional air out. But I'm debating now if rather or not that's the best option. Do you all think I'd get more airflow by doing it with equal air in as moving out... (I.E. 2 fans sucking, 2 blowing).

The only reason I was considering not going with 2 in and 2 out is the fact that I was really liking the idea of having the fans blowing directly down the length of the heat sinks. I guess I could use the fans to cross blow the amps.

[Domsz06]

not sure I can help, but make sure that if you have internal fans in your amps that if you do blow lengthwise that your fans are blowing into the fan inlet, and not into the outlet.

Don't ask how I know

[dogbert]

not sure I can help, but make sure that if you have internal fans in your amps that if you do blow lengthwise that your fans are blowing into the fan inlet, and not into the outlet.

He's right. Your additional fans really should be geared towards maximizing air exchange, not necessarily air-flow across the amps. Of course, we're assuming your amps already have fans.

I'm a little confused about your "sealed" box. It implies that there's no air exchange with the outside air whatsoever.

[Domsz06]

yeah that's what I'm assuming he is meaning dog.

[spharis]

And keep in mind the best designs may not going to blow accross the heat sink, in fact that may be least efficient. The more efficient design is going to be perpendicular to the heat sink; similar to a CPU cooler. You want to have as much air as possible move by the heat sink. A parallel vent will blow across a thin layer, vs a perpendicular will force air up and through the entire heigth of the sink to get to the vent location. I would do two perpendicular to the heat sinks, and two venting out. I would have none pushing air in. Then I would add some vent holes, kind of swiss cheese like using a 3/8" drill, on the other side of the amps.

[Domsz06]

I know on mine they are going to be in open air, I'll have two fans blowing over, and then having a fan blow air into the compartment from the bottom of the boat, and another sucking air out to the outside so that way the air turns over in the compartment. That should do the trick,least I hope so.

[dogbert]

BTW, I had to install a fan in the back of my media console cabinet to suck out the hot air from my Xbox 360 and DVR, both of which generate a lot of heat. Both have their own cooling fans, but the cabinet has minimal air flow going through, so the fan does a nice job of circulating air through the cabinet.

[Domsz06]

I'm going to use some blower fans to move the air in and out of my compartment, and some small squirl style fans to move air over the amps. I think that should cover it.

[Tanner]

Dogbert,

Nope these amps don't have fans. Kicker got rid of the fans on the ZX models much to my dismay. My KX's had them, but they got stolen.

When I said sealed, I meant sealed off from the outside environment other than what the fans would introduce.

Today was a busy day.... since I didn't have much work to do I headed off to my cabinet makers shop to remake some boxes since the first one didn't work due to size. This one did... but I totally changed up how I was going to do things. I had already decided to run the fans perpendicular across the heatsinks, and this new layout works alot easier to do it this way as well. Man I hate working in tight spaces

[Domsz06]

yeah tight spaces suck!! well ok, there are some good ones.............................................

[mneal]

Can you post a picture of the setup. I am unsure what you mean, are you just stirring the air in the sealed amp compartment? You need to exchange the air with outside air or the ambient temp in the compartment will continue to rise, fibergalass and wood are horrible thermal conductors. Although amps heat sinks work best with mounted horz fins pointed up, with fans you can easily neglect the slight increase in natural convection, besides almost always they mount sideways for space reasons.

[Moki]

BTW, I had to install a fan in the back of my media console cabinet to suck out the hot air from my Xbox 360 and DVR, both of which generate a lot of heat. Both have their own cooling fans, but the cabinet has minimal air flow going through, so the fan does a nice job of circulating air through the cabinet.

I have that problem right now. My PS3, amplifier, DVD and Satellite are all in the same cabinet. I drilled holes in the bottoms of each shelf and put a vent in the top of the cabinet, but the PS3 really gets it hot in there. How did you hook up your fan, is it hard wired and switched or do you just plug it in?

[whitlock87]

Have you thought about water cooling.
You can get a small trany cooler from Pepboys, and tie it inline with the pickup from the hull. Place the cooler in front of the fans blowing air into the compartment. This will send cool air in and warm air out. One of the biggest problems is that when People make these boxes, that they forget about the fresh air needed. If you put a box with just fans blowing in and out, it could work fine as long as the air is being replaced with fresh air. If you then place that box inside a storage compartment, then you do not have any fresh air so the temp will keep rising until the air is replaced or cooled by other means. This is where the trany cooler will help.

David

[Tanner]

Whitlock,

The problem w/ water cooling is 1. You need to be moving or have the boat on to have the water moving through the system to exchange the heat. This isn't an option for what I'm trying to achieve. 2. You run into corrosion problems w/ the different metals.

mneal,

I'm not just stirring the stale hot air. I'm exchanging it w/ fresh air and moving out the "used air"

[Domsz06]

tanner,

do what I'm going to do, run a blower fan picking air up from the bottom of the boat, as it tends to run cooler there due to the contact with the water, have it blow air into the box/compartment then have another fan sucking from the oppisite side pulling air out going directly outside. I'm doing a set up like this and feel it will be really good.

Now I just need to find a thermometer that has a contact and that goes to a 2 inch gauge so I can put it on my dash to monitor it. Seen anything like that Tanner? (Not trying to jack your thread)