Yup, that’s a rooftop swamp cooler alright. Thanks.
They work! In dry climates.
We have a rooftop swamp cooler and no AC. It works great, keeps the house at around 72 degrees even when it is well over 100 outside. Of course our humidity hovers around 5 to 10% daily in Summer so it works for us.
Wife and I spent a Summer night in an 1890s hotel in East Texas a decade or so ago, no AC just a ceiling fan. Hottest night we ever spent in our lives, it was suffocating.