Cooling Tower Approach and Range
Range, approach, heat rejection (gpm × 500 × range BTU/hr), and fan kW per ton against typical 5-10 °F approach / 8-12 °F range targets.
Formula and source
Range = T_in − T_out. Approach = T_out − T_wb. Efficiency = range / (range + approach) = range / (T_in − T_wb). Heat rejection (BTU/hr) = gpm × 500 × range. Fan kW per ton = fan_kW × 12000 / heat_rejection.
Cooling Technology Institute (CTI) ATC-105 standard practice by name; ASHRAE Handbook (HVAC Systems and Equipment) cooling-tower chapter by name.
Audience
This tile is built for hvac and the adjacent professions in the HVAC group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.