## 4 Exergoeconomic Analysis  
The first law of thermodynamics (energy balance) is most commonly used to evaluate the performance of systems. This rule is related to energy conservation and cannot explain the irreversibilities that commonly occur in different processes. Exergy analysis based on the second law of thermodynamics calculates the irreversibilities during a process and then can be combined with economic analysis to provide solutions to improve of the system performance. Exergoeconomic analysis, by combining the concepts of exergy and \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Component** & **Energy Equation** & **Exergy Equation** & **Irreversibility** \\ \hline \multirow{2}{*}{Compressor} & \(\eta_{comp}=\frac{h_{2}-h_{1}}{h_{2}-h_{11}}\) & \(\dot{E}x_{D,comp}=\dot{E}x_{1}+\dot{W}_{comp}-\dot{E}x_{2}\) & \(i_{comp}=\dot{m}_{dir}(T_{0})(s_{2}-s_{1})\) \\  & \(\dot{W}_{comp}=\dot{m}_{air}(h_{2}-h_{1})\) & \(\dot{E}x_{D,temp}=\dot{E}x_{1}+\dot{W}_{comp}-\dot{E}x_{2}\) & \(i_{comp}=\dot{m}_{dir}(T_{0})(s_{2}-s_{1})\) \\ \hline \multirow{3}{*}{Regenerator} & \(e_{rgg}=\frac{T_{1}-T_{2}}{T_{3}-T_{2}}\) & & \\  & \(\dot{m}_{air}(h_{3}-h_{2})=\dot{m}_{gas}(h_{5}-h_{6})\) & \(\dot{E}x_{D,rgg}=\dot{E}x_{2}+\dot{E}x_{5}-\dot{E}x_{3}-\dot{E}x_{6}\) & \(i_{reg}=\dot{m}_{dir}(T_{0})(s_{3}-s_{2})+\dot{m}_{gas}(T_{0})(s_{6}-s_{5})\) \\  & \(\dot{Q}_{reg}=\dot{m}_{air}(h_{3}-h_{2})\) & & \\ \hline Combustion chamber & \(\dot{Q}_{cc}=\dot{m}_{fuel}LHV\) & \(\dot{E}x_{D,cc}=\dot{E}x_{3}+\dot{E}_{fuel}-\dot{E}x_{4}\) & \(i_{cc}=\dot{m}_{gas}(T_{0})(s_{4}-s_{3})\) \\ \hline \multirow{3}{*}{First gas turbine} & \(\eta_{gt,1}=\frac{h_{2}-h_{3}}{h_{2}-h_{10}}\) & & \\  & \(\dot{W}_{gt,1}=\dot{m}_{gas}(h_{4}-h_{5})\) & \(\dot{E}x_{D,gt,1}=\dot{E}x_{4}-\dot{W}_{gt,1}-\dot{E}x_{5}\) & \(i_{gt,1}=\dot{m}_{gas}(T_{0})(s_{5}-s_{4})\) \\ \hline \multirow{3}{*}{Second gas turbine} & \(\eta_{gt,2}=\frac{h_{5}-h_{2}}{h_{6}-h_{2}}\) & & \\  & \(\dot{W}_{gt,2}=\dot{m}_{gas}(h_{6}-h_{7})\) & \(\dot{E}x_{D,gt,2}=\dot{E}x_{6}-\dot{W}_{gt,2}-\dot{E}x_{7}\) & \(i_{gt,2}=\dot{m}_{gas}(T_{0})(s_{7}-s_{6})\) \\ \hline \multirow{3}{*}{Steam generator} & \(\dot{Q}_{gg}=\dot{m}_{st}\) (\(h_{9}-h_{12}\)) & \(\dot{E}x_{D,gg}=\dot{E}x_{7}+\dot{E}x_{12}-\dot{E}x_{8}-\dot{E}x_{9}\) & \(i_{st,gg}=\dot{m}_{gas}(T_{0})(s_{8}-s_{7})+\dot{m}_{st}(T_{0})(s_{9}-s_{12})\) \\ \hline \multirow{3}{*}{Steam turbine} & \(\eta_{st}=\frac{h_{2}-h_{2}}{h_{9}-h_{10}}\) & & \\  & \(\dot{W}_{st}=\dot{m}_{st}(h_{9}-h_{10})\) & \(\dot{E}x_{D,gt}=\dot{E}x_{9}-\dot{W}_{st}-\dot{E}x_{10}\) & \(i_{st}=\dot{m}_{st}(T_{0})(s_{9}-s_{10})\) \\ \hline \multirow{3}{*}{Condenser} & \(\dot{m}_{at}\) (\(h_{10}-h_{11}\)) & \(\dot{m}_{13}(h_{4}-h_{13})\) & \(\dot{E}x_{D,cond}=\dot{m}_{st}(t_{0})(s_{11}-s_{10})+\dot{m}_{st}(t_{10})(s_{14}- s_{13})\) \\  & \(\dot{Q}_{cond}=\dot{m}_{st}(h_{10}-h_{11})\) & \(\dot{E}x_{10}+\dot{E}x_{13}-\dot{E}x_{11}-\dot{E}x_{14}\) & \(\dot{m}_{13}(t_{0})(s_{14}-s_{13})\) \\ \hline Pump & \(\dot{W}_{p}=\frac{\dot{m}_{at}\cdot\dot{m}_{13}(P_{2}-P_{12})}{\dot{m}_{p}}\) & \(\dot{E}x_{D,p}=\dot{E}x_{11}+\dot{W}_{p}-\dot{E}x_{12}\) & \(i_{st,p}=\dot{m}_{st}(t_{0})(s_{12}-s_{11})\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Energy and exergy relations used in the combined cycle system shown in Figure 3.  
economics provides insights and strategies for improving the performance of the system that cannot be achieved exclusively by exergy analysis or economic analysis. It is clear that in the exergoeconomic analysis, the simultaneous reduction of the exergy destruction, exergy loss and the cost resulting from these losses as well as the economic cost of each component of the system are taken into account [28]. In recent years, many exergy-based economic analyses have been provided by researchers (such as exergoeconomic analysis, thermoeconomic analysis, etc.). One of the methods most frequently used by researchers is the fuel exergy, product exergy and exergy loss method that first described by [PERSON] [28].