Advanced Thermodynamics

[Bdupre]

I am super lost here. I keep getting 26% thermal efficiency using first law analysis and cannot figure out what I am doing wrong. The paper I am using to help solve this problem is Teaching Power cycles by comparative first-amd-second-law analysis of their evolution by Dunbar et al.


Thanks in advance for the tips!

 

[onatirec]

Could you show your clear and detailed calculations? I haven't worked through it myself, but the problem statement doesn't say that Figure 5 is correct.

 

[Bdupre]

Here are my calculations

 

[Bdupre]

Attached is the peer reviewed paper these diagrams come from.

 

[onatirec]

You'll notice they have a net (84.9 - 2.5) percent of the system energy coming from the heat exchanger, whereas you're considering that 100% for your efficiency. You're comparing different things.

The problem wants you to work through each stage in the cycle. There are also pump and turbine inefficiencies mentioned in the paper, so Wt and Wp are not exactly the change in enthalpy across them.