I love your greenhouse, CJ !
I have to agree with Ken about the heat... even way up here in the north, and with the doors wide open, this time of year when our high temps are only about 40F, my GH can easily get up to 100° when the sun is out. The summer, obviously is even worse...
My GH only really gets utilized for seedlings in the spring (most of which actually get started under lights in the house, to avoid the expense of heating the GH), although I do keep a few of my heat-loving houseplants in there all summer.
Probably wouldn't be a total solution, but I would think having an exhaust fan in that back window could help remove some of the built-up heat.
