I love my attached
greenhouse! In winter when there's no greenery outside I stagger out into the
greenhouse with my morning cuppa tea, and just love it. We remove our greenhouses completely in the summer, because they are made of plastic film and we just roll them up and tie them under the eaves. I think it would be better to have a way to open yours as much as possible, rather than trying to cool a greenhouse in the hot AZ summer sun. It's also important to have thermal mass to store a bit of warmth and coolth through at least a few days and nights.
If it's a sunroom with vertical glazing and a solid roof,
and if the south side is exactly south facing and vertical, it won't get much sun in the summer, but that east facing side will soak up lots of heat on the long summer mornings. Also, in that case you'll need to have your perennials in containers to take out into summer sun. I really like the simplicity of our greenhouses that are on for the winter and open for the summer.
I grow leafy greens and herbs in the winter, and flowers all year in my attached greenhouse space. Eliot Coleman's
books are wonderful for learning how to grow vegetables through the winter. Here in the desert I feel the greens actually do better in the greenhouse in winter than they do out in the gardens in summer, but it might just be the closer attention I give them because they're so close to home. Other attached greenhouses at our school, we use for leafy greens, spring seedlings, and perennials that are not considered quite hardy outside here, like grapes and strawberries.