$1\mathrm{.}29$ A $600-M{W}_e$ power plant has an efficiency of $36$ percent with $15$ percent of the waste heat being released to the atmosphere as stack heat and the other $85$ percent taken away in the cooling water $($see Figure P$1\mathrm{.}29).$ Instead of drawing water from a river, heating it$,$ and returning it to the river, this plant uses an evaporative cooling tower wherein heat is released to the atmosphere as cooling water is vaporized.

At what rate must $15C$ makeup water be provided from the river to offset the water lost in the cooling tower?

Stack heat

Evaporative cooling

FIGURE P$1.29$