## 4 Discussion and Conclusions
The ABC optimization process shows how exergy destruction in all components including condensers can be reduced. For example, the exergy destruction of CON 1 and CON 2 in the real system are 3.65 MW and 4.34 MW, while in the ABC optimization process, these values reduce to 1.77 MW and 3.16 MW, respectively. PU 1 and PU 2 are most affected by pollution and blunting problems in CON 1 and CON 2. Under all optimization conditions, the exergy efficiencies of the turbines TURB 1 and TURB 2 are the same. As a result, for beneficial exergy of the GPP, net power generation is noted. The components with highest exergy efficiency are CON 1 with 94%, TURB 1 with 93% and VAP 1 with 92%. The exergy destruction rates reach this level in TURB 1 and TURB 2 due to temperature differences, leaks and pressure falls. The improvement potential for Sinem GPP is found to be 84%. Thus greatest improvement among system components are present for CON 2, VAP 2, CON 1 and TURB 2. Components with the least improvement potential are pumps (PU 1 and PU 2) and the recuperator RECUP. According to the exergy rate entering the system, the exergy improvement potentials of system components are in the order CON 2, VAP 2, CON 1 and TURB 2; however this order is not the same in the exergy analysis. It appears that with developing technology, the efficiency of geothermal power plants continue to increase. At Sinem GPP there are problems such as inability to set the flow rate, temperature and pressure of the geofluid (brine) and/or keeping it low, the high temperature of geofluid, the high working temperature, the use of a recuperator on level I but not on level II, the binary turbines linked to the generator with the same shaft, the insufficient flow of geofluid steam and the high NCG content, the turbine leaks and losses, and the design/operating problems with the air-cooled condenser. Thus, though the exergy inputs are high, the electricity generation amount and efficiency of the power plant are low, so it appears not to work efficiently. Finally, the ABC optimization method in this study can provide higher quality information than exergy analysis. If geothermal power plants can be studied with similar methods in this study, serious energy and cost savings may be ensured. The ABC optimization method can be completed for all power plants operating in accordance with the organic Rankine cycle. The authors gratefully acknowledge the support provided for the present work by the Maren Geothermal Inc. and the personal support of the managing director, [PERSON]. The authors are very grateful to the reviewers due their appropriate and constructive suggestions as well as their proposed corrections, which have been utilized in improving the quality of the paper. All authors contributed to writing the article on equal terms. All authors read and approved the final manuscript. **Conflicts of Interest:** The authors declare no conflict of interest. **Nomenclature** \begin{tabular}{l l} c\({}_{\text{p}}\) & specific heat (kJ\(\cdot\)kg\({}^{-1}\)\(\cdot\)K\({}^{-1}\)) \\ C & heat capacity rate (kW\(\cdot\)K\({}^{-1}\)) \\ \(\dot{\text{E}}\)x & exergy rate (kJ\(\cdot\)s\({}^{-1}\) or kW) \\ h & specific enthalpy (kJ\(\cdot\)kg\({}^{-1}\)) \\ \(\dot{\text{I}}\) & irreversibility (exergy destruction) rate (kW) \\ \(\dot{\text{m}}\) & mass flow rate (kg\(\cdot\)s\({}^{-1}\)) \\ P & pressure (kPa) \\ q & unit heat transfer rate (kW\(\cdot\)kg\({}^{-1}\)) \\ \(\dot{\text{Q}}_{\text{k}}\) & heat transfer rate (kW) \\ s & specific entropy (kJ\(\cdot\)kg\({}^{-1}\)\(\cdot\)K\({}^{-1}\)) \\ \(\dot{\text{S}}\) & entropy rate (kJ\(\cdot\)K\({}^{-1}\)) \\ T & temperature (\({}^{\circ}\)C or K) \\ \(\dot{W}\) & work rate, power (kW) \\ \end{tabular}   
**Greek Symbols** \begin{tabular}{l l} \(\Delta\) & difference (-) \\ \(\varepsilon\) & exergy or second law efficiency (\%) \\ \(\ddot{\text{r}}_{\text{k}}\) & effectiveness (-) \\ \(\eta\) & energy or first law efficiency (\%) \\ \(\Phi\) & random number (-) \\ \(\psi\) & flow exergy (kJ\(\cdot\)kg\({}^{-1}\)) \\ \end{tabular}