we have more than enough solar panels to greatly offset all of our fan use. 
 i think the idea of the solar panel units was to avoid the cord dangling down into the space.

getting 3 or 4 of those 1000 cfm solar units would, imo, be perfect.

i'm concerned the fan that's currently installed has poor air flow as it's blowing directly against a parabolic dish & it's not weather proof (wind + rain = fan dies)