On August 5, 2017 at 17:19, Audiophiliac said...
The options recommended by ATM and MA and Cool Components all seem to move as much CFM as the advertised flow of some of the fans at Home Depot designated for "large" rooms. CFM is CFM regardless of heat load.
Well, yeah, that's true. But for a given CFM, a lower heat load means the closet will be a lower amount of degrees warmer than the room. As your heat load goes up, the result of X CFM will be less and less.
I like the large lower air gap, too.
The fan can be vented to atmosphere if necessary. I can either tie into existing trunk from another exhaust fan or duct to the existing attic exterior vent location.
The first paragraph, now with some added details, also is added to by this. Whatever you tie into will change the CFM. If you try to exhaust into the wind at your exterior vent location, CFM will lower. All the factors are tied together.
My main question was basically if there is any tangible benefit of using something 5-6 times the cost of the cheap solution.
If you had stated just that you might have gotten more help.
If CFM is the key, it seems that any option that provides the appropriate air movement would serve the purpose.
CFM is A key, and back pressure from the tubing, and heat load, are other keys.
Fan noise is the only concern in the back of my mind.
The best thing you can do to help with that is to put a thermostat in the closet. When you turn on the system, the fan won't come on right away. By the time heat turns on the fan, the movie will be playing, so fan noise will be masked. When you're done and the fan stays on for a while, you'll be done -- and therefore not paying much attention to fan noise. And it'll shut off when things cool.
When I am motivated, I could calculate the heat load of the rack, but my guess is that is within the range that would be addressed by the recommended solutions from ATM, and others.
I haven't heard any ideas of how to relate the heat load to CFM or even to temperature rise assuming zero CFM. There's still a lot of facts to gather.
But chances are a quiet fan with minimal ducting and a control thermostat is all you need and will save you from learning all the formulas needed to tell you that what you put in was exactly right.
Try something and take notes.
