Very nice! I have a couple questions about your swamp cooler. I have a similar setup, where I have about 70 GPUs running on a 4 foot rack just like yours. Our climate has very hot and dry summers also, and I'm trying to find the best cooling solution. Have you had any issues with your swamp cooler? Do you know what size it is (CFM)? And you said you're blowing the hot air directly into the swamp cooler, not blowing cool air in from behind the rigs, right?
My rigs are housed in a 4'x8' mylar tent, which has allowed me to manage dust and heat very well. I have duct fans pulling air in and out of the tent at a rate of 3000 CFM, which has worked pretty well during the winter, but it's not enough for summer. I'm trying to figure out how big of a swamp cooler I might need to provide additional cooling.
Thanks for sharing!