Here is the real life problem I am facing: Gas reciprocating engine is situated in an engine room. The engine is primarily cooled by jacket water flowing to remote radiator. The engine surface must also be cooled by forced convection to maintain max air inlet temp of 40C. Ambient can reach as high as 40C as this is a tropical climate. How do I size a ventilation fan for this set-up? What inputs do I need to start calculating? Where should I locate the ventilation fan?