Hello njens-
One problem that is difficult is keeping the greenhouse cool!
All that sunlight really heats it up.
Many greenhouses have a "window" in the roof, and an automatic opener so it will open and vent in warm weather.
Here is something you could do "for real" and not just as a project: the openers currently available to the home gardener open and close automatically, they have some kind of liquid in them It must not freeze so the gardener must dismantle it every fall and reinstall it in the spring, and be absolutely perfect-if it freezes it is ruined. So of course they freeze. They are expensive.
Big commercial greenhouses have electric vents on a thermostat, but the average home greenhouse owner does not have electricity.
I have a little "cold frame", which is a sort of mini greenhouse, that I bought about 25 years ago. It has a different (better) opener device. I wanted to find another a few years ago, could not find anything on the internet that was at all like it. It is a "bimetallic" opener, with NO fluids or batteries or anything. The way it was described it is two kinds of metal, fused into a bar so one side is one metal, the other side a different metal. Each bends at different temperatures, so below about 75 degrees Fahrenheit it is straight, above that temperature it bends, which opens the plastic cover and vents the heat. It still works perfectly after all these years. There is nothing to break. If you could reinvent this it would be great!
Also, standard greenhouses sold to the hobbyest, usually have vents on the top. This is not enough, for proper airflow and venting an opening at the bottom is also required, so as not to cook your plants.
Good luck I would like to see your finished project!
