Considering how much air movement and heat we're talking about here, the actual motor and pump housing heat yield should be measured and the selection developed on that basis....As well as some control scheme to modulate the fan with demand. Even a utility has to think twice about connecting a 1000-hp motor to a single fan and letting it run on simply a thermostat on the exhaust side.
Typical feedwater pump room arrangements will require some pretty specific geometry for the air introduction and circulation, to the point where many are built double wall and drop ceiling so the wall cavity is one plenum and the interstitial space is another. Some use cooling tower water to prechill incoming air at highest outdoor ambients, depends whether ambient temp profile only rises to within 5% of peak temperature for 10% of total time, or 25% of total time.
