# Homework Help: The rate of thermal energy transfer

1. Mar 15, 2013

### Marshiewoo

A steady flow boiler takes in feed water at 1.5kg/s, at a temperature of 30 °C. The water is heated and turned into wet steam. This leaves at 1.5kg/s, with a pressure of 10 bar and a dryness fraction of 0.97 to the superheater, where it receives heat at a constant pressure and emerges at a temperature of 400 °C.

Determine, using steam tables:
A. the rate of thermal energy transfer in the boilet
B. the rate of thermal energy transfer in the superheater

--------------------------------------------------------------------------------

I have managed to find out the efficiency of the turbine, which is after the superheater.

I am not really looking for an answer, although that would be fantastic. I would mainly like somebody to explain the difference between what I have worked out (below) and what the question above is asking.

--------------------------------------------------------------------------------

My attempt at a different task which is slightly related:

Thank you and my apologies for the terrible use of the fantastic itex system.

2. Mar 15, 2013

### SteamKing

Staff Emeritus
The water didn't turn itself into steam before it reached the turbine.
A boiler was used to first heat the feed water and turn it into slightly wet saturated steam. What was the rate of thermal energy transfer required to do this?
Second, the saturated steam was then superheated. What was the rate of thermal energy transfer required for this step? Use steam tables to answer both questions.

I don't know how the question could be any more clear than as stated.

3. Mar 15, 2013

### Marshiewoo

So I just use the steam tables? :s