Steam enters the condenser of a steam power plant at 20 kPa and a quality of 95 percent with a mass flow rate of 20,000 kg/h. It is to be cooled by water from a nearby river by circulating the water through the tubes within the condenser. To prevent thermal pollution, the river water is not allowed to experience a temperature rise above 10°C. If the steam is to leave the condenser as saturated liquid at 20 kPa, determine the mass flow rate of the cooling water required.
5 comments:
graham 3:26 PM
Good question.
Assume the cooling water has a constant heat capacity of 4.18 kJ/kg*K and use deltaH=Cp*deltaT.
I should have put this in the hints.
I have the same question as graham. I used the H values for water at 40 and 50 degrees C and 1 atm and got an answer of 312 kg/s. But that seems too much off. Is there a way to get a more accurate delta H?
greenpepper7 9:31 PM
Good question again.
The answer I just posted for Graham should clear this up.
Anyone know why im getting like 5357kg/s ? I am using the m1deltaH1=m2deltaH2 formula, with all dimentional analysis included!
Kanto 9:43 PM
My guesses would be:
1- You accidentally used 0.2 MPa instead of 0.02 MPa.
2- You did not properly convert the mass flow rate from kg/h.
I hope you find the error and let us know.
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