I picked up one of these fans at the local computer store.

http://www.memoryexpress.com/Products/MX37348

Specs are 156.27 CFM and 1.81 mmH2O pressure. Runs nearly silent.

This this enough or should I go for a louder/faster fan?

I am unclear, do you need to keep one of these coolers outside your structure/yurt and pipe cold air in or can you just run it inside?