### Chiller and Tower Sizing Formulas - Water Chillers

TOWER SYSTEM DESIGN FORMULAS. Cooling Tower = 3 Gallons per Minute per ton. 1 Tower Ton = 15,000 BTU/hr. Tower Ton = GPM x ΔT/30. CHILLER SYSTEM DESIGN. Chiller = 2.4 Gallons per Minute / ton. 1 ChillerTon = 12,000 BTU / hr. Chiller Ton = GPM x ΔT / 24.