DIY Evaporative Cooling in a Heat Wave

At home, we only have A/C units on the second floor, and I do most of my work on the Mac, which is on the first floor. Yesterday the New York metro area wasn't just hot, it was Africa Hot, and today looks to be more of the same, but I've got work to do. This morning I lowered all the blinds in an attempt to keep the heat out, and set up the window fans on tables with shallow baking pans full of water in front of them. The idea is that the air flowing from the fans will evaporate the water and cool down the room.

DIY Evaporative Cooling in a Heat Wave
WARNING: SCIENCE CONTENT BELOW

How much you can cool a room using this method is dependent on the relative humidity on that particular day. The less relative humidity, the more water you can cool the room down. I found a quick and dirty formula for calculating the "Wet Bulb" temperature, which is the lowest possible temperature you can attain by evaporation alone given the current atmospheric conditions. It turns out that today's wet bulb temperature is 84 degrees, which will feel around 80 for me with the fans going - a bit hot, but definitely tolerable. The thermostats on the fans are holding at 85 right now. However, we haven't reached the hottest part of the day yet - I'll update later this afternoon to see how the experiment worked out.
DIY Evaporative Cooling in a Heat Wave
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