The above comments about cleaning fins, adding water mist to the air and considering wind screens are all very valid points.
Is your ACC a flat horizontal or a hexacoil system?
You state that your fans are maxed out.
I assume that you mean these are at maximum pitch and/or the amperage draw from the motors is maxed out.
Both of these do not neccesary mean that the aerodynamic performance is maximized.
I would suggest to have the fan performance valuated by having the aerodynmaic performance measured, with clean bundles is best. There may very well be the potential to increase th air flow in the ACC with minimal technical impact and low investment.