R & R - building new Stevenson Shield - Questions

Not quite sure which sub-group to post this in - so please move as necessary.

I’m refurb’ing / rebuilding my 7-8 year old Stevenson shield (desert heat and dust storms are killers) and I’m thinking of adding a solar powered fan to it. I have some small solar panels 2.2v, 45ma, which I can wire in series / parallel to get close to a 5v, 80ma level, which, according to a spec sheet I reviewed will comfortably drive a 3 inch / 80mm computer case fan.

Question is, what’s best? Fan at the bottom of the ‘box’, blowing air in, or at the top - blowing it out. Either one will be moving air around, but which one is the most efficient for air flow?

Prototype testing with a 2 in gap all around the bottom, and a 1.5 in gap all around the top, the test tracks .8F to 1.3F higher than the mean of 3 stations (old ones, good for something) currently in the old shield. When I put a 2nd top - raised 2in - and overhanging by 2in each side, I drop it to .4F to .9F in direct sun exposure. Playing now with ventilation etc. If I can drop it to a constant .4 / .5 F, I’ll be satisfied.

Beauty of all this is it’s not an “oh hell, gotta build a new box quick-like” and I can play around a bit.

Anyway, I’d grateful for any feedback or advice.

Ken

(posted in both forums)

Theoretically the fan should be exhausting air, not blowing it in, so that the air temp isn’t affected by passing by the “hot” fan motor.

Thanks Niko.

I’ll plan to vent it thru the 1st ‘top’, under the 2nd one.

Ken