Evapco, McQuay, Marley, and BAC Cooling Towers Nominal Tons
Product capacities are called out in terms of nominal tons. A nominal cooling tower ton is defined as the capability to cool 3 GPM (0.19 lbs) of water from a 95ºF (35.0ºC) entering water temperature to an 85ºF (29.4ºC) leaving water temperature at a 78ºF (25.6ºC) entering wet-bulb temperature. Nominal conditions are typical of conventional HVAC designs in most parts of the country, but will not apply to all projects.
Average Monthly Wet Bulbs Temperatures – Western Regional Climate Center