As we spend time designing the Mobile Multipurpose Network Node (M2N2), one of our biggest design challenges has been the power required to run cooling for the on board electronics - small servers etc. This paper from Intel outlines their test results from running a high density server rack using only an air economizer (essentially a customized air conditioner that only kicks on at or above 90deg F and is a blower the rest of the time).

This is very promising for our design since it allows us to rethink our assumptions about high temperature, dirty air and failure rates, which may mean we can cool with a much smaller solar/wind system than we previously thought.

http://www.intel.com/it/pdf/Reducing_Data_Center_Cost_with_an_Air_Econom...