## 5 Conclusions  
This study set out to employ the greywolf approach for the multi-objective optimization of a solar-assisted CCHP system. This was undertaken in a bid to boost the overall efficiency by maximizing the net power and exergy efficiency of the CCHP system. It also sought to optimally reduce the greenhouse emission that has evidently negative health implications and causes global warming. This research supports the idea that there is a need to reduce fossil fuel depletion rate, as a solar-assisted CCHP was optimized. In so far as related studies have employed other optimization techniques for the multi-objective optimization of a solar-based CCHP system, this study proposes a new optimization approach. The results and findings from this research are outlined as follows:  
* A multi-objective optimization approach is used to determine the optimal set of parameters describing the thermodynamic configuration of the solar-based CCHP system: compression ratio, pinch point temperature difference, inlet turbine temperature and inlet combustion chamber temperature. * The performance of the CCHP system is assessed through the net power, CO\({}_{2}\) emission and exergy efficiency that are employed as objective functions to determine how well each set of decision variables complies with all the constraints. * The greywolf technique is employed for the multi-objective optimization to generate non-dominated Pareto optimal solutions. * A set of Pareto optimal solutions are computed in this study. The optimal solutions are provided as options for the decision maker to help them make a preferred selection based on their discretion to improve the performance of the CCHP system. A guide, with which to aid this decision-making process, is suggested via the conducting of a sensitivity analysis. * An interesting finding is the interdependency between the four decision variables. This suggests that a change in one of the decision variables results in respective changes in the other three variables. Hence, a multi-objective optimization technique is pertinent and helpful when evaluating the performance of the CCHP system. * This study found that there exists a conflict in decision-making processes between net power and CO\({}_{2}\) emission as a maximum net power correlates with an undesirable maximum emission of CO\({}_{2}\). Another important finding is the compatibility between the exergy efficiency and CO\({}_{2}\) emission, which indicates that a system with minimal emission of CO\({}_{2}\) is a highly efficient one. This study has shown that a system's high net power production is not a guarantee of its high efficiency, due to the negative correlation obtained between net power and exergy efficiency. * The findings from the sensitivity study suggest that a lower compression ratio will significantly reduce CO\({}_{2}\) emission while having little impact on the optimal net power and energy efficiency values. It was also found that higher turbine inlet temperature values will result in a system that is highly efficient and emits less CO\({}_{2}\), but at the cost of having less net power. This also implies that lower values of combustion chamber inlet temperature are necessary to achieve the minimum CO\({}_{2}\) emission values and maximum energy efficiency corresponding with a minimum net power. * Finally, the study has confirmed the finding of [PERSON] et al. (2018) who found that the compression ratio had the most effect on the CO\({}_{2}\) emission by virtue of having the highest incremental change. In the same vein, the inlet turbine temperature had the most effect on the exergy efficiency while the inlet combustion chamber had the most effect on the net power. Conceptualization, methodology, formal analysis, writing--original draft preparation, U.U. ; writing--review and editing, supervision, L.T. and C.W.L. All authors have read and agreed to the published version of the manuscript.