Water Evaporator and Condenser Equations
Air conditioner heat loads and evaporator and condenser water flow rates.
Total heat load:
h = cp ρ q dt
= 500 q dt (1)
where
h = heat load (Btu/h)
cp = 1 (Btu/lbm oF) for water
ρ = 8.33 (lbm/gal) for water
q = water volume flow rate (gal/min)
dt = temperature difference (oF)
Evaporator water flow rate can be expressed as
qevap = 24 hevap / dt (2)
where
qevap = evaporator water flow rate (gallons per minute - gpm)
hevap = air condition load (1 refrigeration ton = 1 TONScond = 12,000 Btu/h = 200 Btu/min = 3,025.9 k Calories/h = 12,661 kJ/h = 3517 kJ/s = 3517 kW = 4713 HP )
Condenser water flow rate can be expressed as
qcond = 30 hcond / dt (3)
where
qcond = condenser water flow rate (gallons per minute - gpm)
hcond = air condition load, chiller tonnage (1 cooling tower ton = 1 TONSevap = 1 TONScond x 1.25 = 15,000 Btu/h = 3,782 k Calories/h = 15,826 kJ/h)