Idle hands are the devil's workshop, they say. Here's something I whipped together this afternoon out of an item I bought on impulse a couple of weeks ago plus some of the nearly endless supply of junqe in my workshop areas.
It starts out as a solar powered auto vent, gets partially disassembled, then reassembled to the upper fridge vent, with the intake fan on the inside and the solar panel on the outside. Voila! Free air movement. It's no great air mover but I think it'll help direct the convection that should already be happening inside the vent area toward the outside, and start automatically whenever the sun hits it. I want to also install some internal baffles to ensure that convection currents pass over the upper coils on their way out. See other posts already on this forum about making/installing baffles (were they by Rawlus? Pooniel? Sorry that I don't recall at the moment).
Some relevant pics:
Starting with a $10 item.
This is the intake side.
Exhaust side with solar panel.
Drill out four plastic plugs to get at the screws holding it together.
Cut these wires about midway to separate the halves.
Come up with some way to attach the intake fan on the inside of the upper vent grill.
Likewise find some way to hold the panel to the outside, preferably at an angle, then wire the two parts back together.
I made an air duct out of hobby brass to ensure the air actually leaves the vent area.
This is what shows. Completely removable with 4 screws. I may want to add some padding to the panel for travel protection.