Chapter 5, Problem 5.44P

(a)

Interpretation Introduction

Interpretation :

Determine the maximum possible thermal efficiency of the plant and minimum rate at which heat must be discarded to the river.

Concept Introduction :

The maximum thermal efficiency of plant is possible if and only if plant considers as a Carnot engine. The thermal efficiency of Carnot engine is

  ${\eta }_{\text{max}}=1-\frac{T_C}{T_H}$......(1)

And efficiency also write as

  ${\eta }_{\text{max}}=\frac{\left|\stackrel{•}{W}\right|}{\left|\stackrel{•}{Q_H}\right|}=1-\frac{T_C}{T_H}$

(b)

Interpretation Introduction

Interpretation :

Determine the heat is discarded to the river and the temperature rise of the river if it has a flow rate of $165{\text{m}}^3.{\text{s}}^{-1}$ .

Concept Introduction :

The actual thermal efficiency of the plant is calculated as:

  $\eta =\gamma {\eta }_{\text{max}}$

Where

  $\gamma$ is deviation from the maximum thermal efficiency.

And efficiency is

  $\eta =\frac{\left|\stackrel{•}{W}\right|}{\left|\stackrel{•}{Q_H}\right|}=1-\frac{T_C}{T_H}$