There are some little tweaks she could have done to make it more compact and efficient, but it looks perfectly functional to me. As long as it does the job, she can be proud of her engineering.
Some suggestions, if you're considering making one yourself:
- Corrugated heat absorption surface instead of flat. It would increase the amount of surface area heated by the sun.
- Instead of having the air wind around a serpentine path, have a large collection header at the very top and a narrow supply outlet running the full length of the bottom. This would spread out the incoming cooler air allowing it to heat faster and more efficiently. Plus, the action of the rising hot air would help the fan run more efficiently.