This is SUPER ghetto but works in a pinch:
1. Get some sort of tray, preferably plastic, or in this example I went to artist hospitality and got the bottom of a soda can tray which was cardboard and had edges.
2. Lay a trash bag in it so it holds water. When you think you’ve reinforced everything well enough with gaff tape, better add some more gaff tape.
3. As close as possible to your set, fill the tray with ice. Hopefully you’re good friends with the cute hospitality girl at this point.
4. Lay your laptop cooling pad across the top.
You need some separation so you don’t end up blowing water into your laptop!!
5. If you can, cover whatever parts of the ice tray are still exposed with another trash bag to help seal in the air
This setup lasted 90 minutes in Singapore heat/humidity and I had solid FPS the whole show.