Following up on the work of the engineer in problem 5.19, another engineer proposes adding several modifications to the steam power plant. He proposes in his design to have the heat be added to the steam at 550oC, the heat still be rejected to cooling water at 20oC, and that 300 MW of power will be produced from a heat input of 400 MW. Is this process possible?
Given: Proposed: TH = 550oC = 823 K; TC = 20oC = 293 K; Q?H=400 MW; W?=300 MW
Compare the actual proposed efficiency to the Carnot efficiency for the heat engine:
nproposed = W?/Q?H = 0.750
nmax = 1 – TC/TH = 1 – (293K/823K) = 0.644
As nmax < nproposed, the process is impossible.
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