Calculators
Cooling Tower Thermal Rating
Range, approach, heat duty, evaporation, blowdown, and makeup water rates for a mechanical-draft cooling tower, plus air mass flow, fan HP estimate, and economic approach screen. Rebuilt from Cooling_Tower_Thermal_Rating_v3.xlsx — tons-of-cooling fix applied.
References: CTI STD-201 & ATC-105 (Acceptance Test); ASHRAE 90.1 (energy) and 188 (Legionella); Merkel (1925) and Poppe & Rögener (1991); GPSA Engineering Data Book — Cooling Water Systems. Rules of thumb: evaporation ≈ 0.1% of circulating flow per °F of range; economic approach 7–10°F; tight approaches (<5°F) drive tower size/cost disproportionately. Heat duty in tons uses 12,000 BTU/hr per ton (v3 fix).
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