Definitely some great suggestions here! Do you have a window where you could install a fan? Some fans have an adjustment for taking air out of the room or letting any available breeze come through. You could also let a pedestal fan run while you're away. I know it's only blowing warm air around, but it will definitely help cool teh area.

Ice in the water is a good one, can you fill the bowl before leaving with water and lots of ice?

I also pull down the shades in the house when the temps get high, although here in Maine that doesn't happen very often.

Good luck with your search!!