Dimensionless parameters affecting cooling tower performance?

I'd like to know the dimensionless parameters affecting a counter-flow induced draft cooling tower's performance, or if someone could direct me to an adequate resource .
I'd also appreciate if I could be directed to some good comprehensive resources on cooling tower design
Thanks guys

?2013-04-01T13:10:04Z

Favorite Answer

Ambient relative humidity, definitely. Ambient temperature (is it dimensionless?).