Air Cooling

[Jordan A.]

This being my first FIRST year I have been relying heavily on you guys for some info. However now that our team has gotten to the cooling stage of our design I figure I could help you guys out for a change (not all of you, perhaps not any of you, but I'll try)

I have been an avid "Overclocker" for a few years now (Overclocking is running your computer processor faster than it is rated.) Because overclocking makes your computer run hot you must know a bit about cooling in order to make it work well. Now watercooling is bar far the most fun and best way of cooling for the average person, but since the rules forbid it I will do my best to let you in on some air cooling info.

When thinking of cooling you have to think of it as a whole system. Everything works together to get the maximum air flow. Just sticking fans here or there will not give you the best results you actually have to plan.

Take an inventory on the fans, find out what you have, what CFM they provide (CFM=cubic feet per minute) and then plan accordingly.

Enclosure dynamics are great, you can use an enclosed area in order to direct the air flow in ways you want it. The key is to have as much CFM on intake as you do on outake. For example, say you have a 100cfm fan, a 50 and 2 25's you want to have the 100 going in our out and the other 3 doing the opposite.

Another concept I dont like but has been used is "brute forcing" the idea is you direct ALL your fans as intake and let holes in your enclosure act as the exaust based on the presure built up from the fans. While it works you dont get as high an air flow as you would like.

When designing your air flow take into account where the air goes after it cools a component. It will be hotter than it was comming in. You dont want air going over a really hot motor and then to a speed controller because the motor would heat it up faster than the vic would. Also blowing across something is alot better than down on it. If you blow down on something the exaust from that will generaly spin around into air streams you dont want it to. You can occasionaly get kinds of loops where air is pushed onto something spun back around back into the same stream just getting hotter. Not a good way to cool.

Final concept I'll subject you to is a pretty basic one. Hot air rises. Exausts on the top and intakes on the bottom tend to work the best.

I realize that most teams will be screaming "COOLING SYSTEM!!! We have to worry about our DRIVING system!" and I understand, I really dont think out team is going to have the time to impliment a good one. But its something to think about.

-Jordan Armstrong ~who can't wait for FIRST to legalize water cooling so he can design a cooling jacket for the chipuahs