Viv Temps

[topsyturvy]

Hi i am just thinking of getting my tort a bigger viv, at the moment she is in a fish tank with the top half open which seems to keep the temp right and allows ventilation.
My question is if the viv gets too warm how do i cool it down for her, with the tank i just open up the top.
Hope this doesn't sound a stupid question only i dont know much about keeping the temp right in a viv.

The reason i am thinking of a viv is that she is now getting bigger and needs more room, and i thought it would be better for her over winter, as the room she is in soon gets cool.