# Thermodynamics Question (Power Output)

1. Oct 19, 2010

### WA2000

This is not really homework, it's just something I don't understand and I will be assessed on it soon, so I need some help on it. First off our teacher is the worst teacher you will ever encounter, he gives us the solution but doesn't tell us how (tells us to figure it out ourselves). I tried looking at books but all of them are for advanced thermodynamics (Our thermodynamics is introductary, it's all in pre-calculas level), I really don't understand it and I really need help on this. I'm in semester 3 in the Mechanical Engineering Diploma program at the Australian College in Kuwait.

1.
A steam turbine takes in steam with specific enthalpy 3095 kJ/kgm at a rate of 80 kg/min. The steam leaves the turbine with specific enthalpy 2660 kJ/kg. If heat losses from the turbine are 120 kW, Determine the power output. (Assume that kinetic-energy and potential energy changes are negligible).

All he has given us so far are these equations:
Q-W =H2-H1
Q-W= U2-U1
H= U+pV
H2-H1 =mc(T2-T1)

3. I know for a fact that the answer is 460 kW, But how do you get the answer, can you explain it please?

Any help would be greatly appreciated.