Your best bet woud be to air condition the room. If this stuff is as important to you as you have described, then it should be in a room that is temperature controlled. I know servers that run companies that use less hdd space than you have, and al of them have their servers in air conditioned spaces. A simple fan is not going to solve your problem. Why not look into installing what is called a "Mini Split" in the air conditioning industry, it's a small a/c unit that can cool just one room. If that isnt going to work, due to the room being a sun room, then my suggestion is move the equipment to a room that will. Best of luck.