Evaporative (Swamp) Cooler Leaving Temperature
The supply-air temperature a direct-evaporative (swamp) cooler delivers: T_out = T_db - saturation effectiveness x (T_db - T_wb). 95 F dry-bulb, 65 F wet-bulb, and an 85% pad give 69.5 F. The wet-bulb depression is the maximum possible drop, so a dry climate cools far more than a humid one; the process adds moisture (high leaving RH). Pad effectiveness ~0.80-0.90 rigid media, less for aspen. Direct single-stage only; the equipment data govern.
Formula and source
T_out = T_db - saturation_effectiveness x (T_db - T_wb); temp_drop = effectiveness x (T_db - T_wb); wet_bulb_depression = T_db - T_wb.
ASHRAE Fundamentals direct-evaporative (saturation) effectiveness relation, by name; classical psychrometrics.
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