How many kg of H20 flows each second if heated through 3 C at power station... see specific details?

Question

power station with efficiency 0.4 generates 10 to the 8th power W of electric and dissipates 1.5 x 10 to the 6th power W thermal energy to cooling water flowing through it. how many kg of H2O flows each second if heated through 3 C degrees.specific heat of H2Oin SI units is 4,184j/kg degrees C

Answer 1

40% efficiency means that it takes 250 MW input to generate 100 MW output for the power grid.

efficiency = output / input

That means that waste heat = 250 - 100 = 150 MW

(Your 1.5 x 10^6 should be 1.5 x 10^8)

heat = mass flow x specific heat x delta T

solving for mass flow:

mass flow = 150 x 10^6 / 4184 / 3

= 12000 kg /sec