Cooling Range vs. Approach
Two key terms are often confused:
| Term | Meaning | Depends on |
| Cooling Range | Thot in−Tcold outThot in−Tcold out | Process heat load and water flow rate |
| Approach | Tcold out−Twet bulbTcold out−Twet bulb | Tower’s cooling efficiency and ambient conditions |
Wet Bulb Temperature (WBT) = Lowest temperature achievable by evaporative cooling under local atmospheric conditions.