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. LOAD SIZING FOR INJECTION MOLDING APPLICATIONS : MATERIAL. 30# / hr H.D. Polyethylene = 1 ton.