Cooling a Yurt in the Midwest

[hippiebikerchick]

I bought a can of nightshades, a tint spray that is used to darken car lenses, and I put cardboard up on all windows (they are all facing east). The tint on the dome was not enough, so I covered it with cardboard.The yurt gets some shade late afternoon, otherwise it's completely open. I have a 12k btu rated at 400 sq ft, the yurt is 300. Even with all of this, I can't hold the temp. The walls and ceiling have the radiant foil bubble wrap. I'm having the windows tinted and I'm thinking of adding another layer of bubblewrap. I'm not sure what else I can do. Anything thicker and I will have to reorder the top canvas.