Work out cooling water requirement instantly with clear inputs, formula shown and shareable results.
Circulating water flow is heat rejected divided by water's specific heat and the allowable temperature rise. A once-through system consumes nothing but discharges warm water; a wet tower evaporates roughly one kilogram per 2300 kilojoules rejected, and blowdown to control dissolved solids adds to make-up demand.
Circulation rate
Flow (kg/s) = heat rejected (kW) / (4.18 x temperature rise)
Tower water balance
Evaporation = heat / 2300; blowdown = evaporation / (cycles - 1); make-up = evaporation + blowdown
Cooling water abstraction and thermal discharge are subject to environmental permits, including temperature limits and impingement protection requirements.
Cooling is achieved by evaporating water, so consumption is inherent to the mechanism. A 1000 MW thermal rejection evaporates about 430 kg/s, over 37,000 tonnes a day.
Scaling and corrosion as dissolved solids concentrate. Higher cycles save water but need better chemical treatment and may hit calcium carbonate or silica saturation limits.