I posted this question in the cooling forum: What do you think would be more effective auxiliary electric fan, a
14” @1800cfm or 16” @1600cfm? and some folks rather than answer the question take it as an opportunity to rant. It’s just a question for gods sake!
Lower CFM with larger surface area. Heat extraction is about residence time, not volume and velocity. It takes time to transfer heat and more surface area makes it even more efficient.
Move too fast with a smaller area, and heat exchange rates become less efficient. Larger surface area at lower speed works better.