Some pictures of my first prototype window fan. Trying to not use the AC again this summer, but my crappy garage sale window fan ain’t cutting it. I’m using a 12″ diameter 12V 80W automotive radiator fan and a high efficiency 100W switch-mode power supply. The fan is rated to be 1600 CFM, I can’t measure to verify but it definitely moves a lot of air.
I was hoping to make something that moved a lot of air but didn’t use a lot of electricity. These radiator fans were the most efficient I could find, and the total draw is 88W which is less than my off-the-shelf fan and a lot windier (breezier?).
One toggle switch for power, another for fan direction. The off-the-shelf fan I was using previously had to be removed from the window and put in backwards to change direction, so this is a very satisfying $3 direction switch.
I also added a metal frame to hold a 2″ air filter and foam pre-filter. The hope was to filter the air before it gets sucked into the room through a MERV 13 filter since we live on a very busy street. The metal frame was laser cut and bent on a small brake.
Unfortunately the filters really affect how much air the fan moves, almost stopping it entirely. That’s prototyping though, otherwise the fan is working great. The air isn’t being filtered before it comes in though, but I scored a second-hand austin air healthmate for cheaper than I could build something similar.
The fan motor surface temperature got up to 60C after being on for about 30 minutes, not sure if that’s a problem yet though. Woo, prototyping!