That could work. The critical issue is how powerful the fans are vs. how big your greenhouse is. The fans should push enough air (cubic feet per minute; CFM) to change the air in your green house multiple times per minute.
You can also drape shade cloth (available online and at good garden stores) over the green house to cut down on the amount of sunlight that gets into the greenhouse.
I also live in a locations with intense sunlight and I use fans and shade cloth and I remove the end walls when things get hot.
Good luck!
