The maximum reversible work in thermodynamics (2)

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SUMMARY

The discussion focuses on calculating the maximum reversible work (W_rev) in thermodynamics for an open system, emphasizing the concept of exergy. Key equations presented include the energy balance and entropy balance, leading to the formulation of W_rev as a function of heat transfers (Q_k), enthalpy differences (h_i - h_e), and entropy changes (s_i - s_e). The final expression for W_rev incorporates temperature ratios and is critical for understanding available energy in thermodynamic processes.

PREREQUISITES
  • Understanding of thermodynamic principles, specifically exergy and reversible work.
  • Familiarity with energy and entropy balance equations in open systems.
  • Knowledge of heat transfer concepts and enthalpy calculations.
  • Basic proficiency in thermodynamic temperature scales and their applications.
NEXT STEPS
  • Study the derivation of exergy and its applications in thermodynamic cycles.
  • Learn about the implications of entropy generation in irreversible processes.
  • Explore advanced topics in thermodynamic efficiency and performance optimization.
  • Investigate the role of temperature gradients in energy transfer and conversion.
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Students and professionals in mechanical engineering, thermodynamics researchers, and anyone involved in energy systems analysis and optimization.

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Homework Statement
Open system, maximum reversible work relative to the dead state in a thermodynamic process. I will share the solution process with everyone, and please correct me if there are any mistakes.
Relevant Equations
Exergy balance
Energy balance
Entropy balance
1712596768815.png

referencesol
The maximum reversible work in thermodynamics
Below is the process of determining the "Available energy" for an open system, shared with everyone as a reference for learning about exergy. If there are any errors in the content, please feel free to correct them.

$$ W_{rev}=W_u^{\nearrow W-P0\cancel{\left( V_2-V_1 \right) }=W}+T0\cdot Sgen=W+T0\cdot Sgen $$
Find## W ## and## T_0\cdot Sgen ## :
$$ eneger\ balance:\ \ Q_{in,net}^{\nearrow ^{\sum{Q_k}}}-W_{out,net}^{\nearrow ^W}+m\left( h_i-h_e \right) =\cancel{\bigtriangleup E_{sys}} $$
$$ \therefore W=\sum{Q_k}+m\left( h_i-h_e \right) $$
$$ entropy\ balance:\ \cancel{\bigtriangleup S_{sys}}=\sum{\frac{Q_k}{T_k}}+m\left( s_i-s_e \right) +Sgen $$
$$\therefore T_0Sgen=-\sum{\frac{\ T_0}{T_k}}Q_k-T0\cdot m\left( s_i-s_e \right) $$
$$ \therefore W_{rev}=\sum{\text{(}1-\frac{\,\,T_0}{T_k}\text{)}}Q_k+m\left[ \left( h_i-h_e \right) -T_0\left( s_i-s_e \right) \right] $$
$$ \therefore w_{rev}=\sum{\text{(}1-\frac{\,\,T_0}{T_k}\text{)}}q_k+\left[ \left( h_i-h_e \right) -T_0\left( s_i-s_e \right) \right] =\text{(}1-\frac{\,\,T_0}{T_1}\text{)}q_1+\text{(}1-\frac{\,\,T_0}{T_2}\text{)}q_2+\left[ \left( h_i-h_e \right) -T_0\left( s_i-s_e \right) \right]…. (Ans:w_{rev})$$
$$ i=w_{rev}-w_u^{\nearrow ^0}=w_{rev}............\left( Ans:i \right) $$
 
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I agree with the result in the reference you gave.
 
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