# Developments, Trends, and Challenges in Optimization of Ship Energy Systems
## Appendix A Main Characteristics of Journal Articles on Optimization of Ship Energy Systems
The ship has high pressure gas injection engines for propulsion and duel fuel DG sets. Design optimization. Comparison of alternative configurations of the BOG rela liquefaction systems. Objective: minimization of the total annual cost. Algorithm: PSO. * [75] [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] _Energies_**2019. ** System: ORC exploiting the low temperature of the LNG (\"cold\" energy) for condensing the working fluid in LNG-powered ship with two alternatives: high-pressure DF engine and medium-pressure DF engine. Jacket cooling water is the heat source. Three alternative configurations are studied for each alternative (high-pressure DF engine and medium-pressure DF engine) with nine alternative working fluids. Design optimization. Objective: max \(\psi_{cx}=\hat{W}_{net}/\Delta Ex\) where \(\hat{W}_{net}\) the net power output of the ORC system and \(\Delta Ex=Ex_{LNG}-Ex_{NG}\) the total exergy supplied to the ORC system by the LNG streams. Algorithm: PSO. * [76] [PERSON], [PERSON]; [PERSON] [PERSON] _Ocean Engineering_**2019. ** Theory. System: slow speed diesel engines and propellers in LNG carrier. Constant weather conditions are considered. SDO optimization. Strength and cavitation of propeller blades is estimated along the way. Objective: maximize NPV. Algorithm: not clearly specified. * [77] [PERSON], [PERSON]; [PERSON] _Ocean Engineering_**2019. ** Application. System: slow speed diesel engines and propellers in LNG carrier. Constant weather conditions are considered. SDO optimization. Strength and cavitation of propeller blades is estimated along the way. Objective: maximize NPV. Algorithm: Differential Evolution Optimization Algorithm. * [78] [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] _Energy Conversion and Management_**2019. ** System: dual loop ORC system, absorption refrigeration unit, Exhaust gas purification unit (destulfarization and denitrification) based on photocatalytic oxidation in bulk carrier. Design optimization. Objective: maximize the equivalent power output of the combined system (net power of the dual loop ORC + equivalent power of the absorption refrigeration (electric power that would be required by a compression refrigeration unit). Decision variables: mixture ratios of the high temperature and low temperature ORC, evaporation pressure, and condensation temperature of the high temperature ORC. Algorithm: GA. EEDI, EEOI, energy and exergy efficiencies, and reduction of SO\({}_{\text{x}}\) and NOx are calculated after optimization. * [8] [PERSON] [PERSON]; [PERSON]; [PERSON] _Energies_**2019. **_Static problem._ System: superconfiguration including gas turbines, bottoming Rankine cycle, exhaust gas boiler, auxiliary boilers, and DG sets. SDO optimization. Four operating states. Objective: minimize PWC. Algorithm: GA. One-step solution of the problem. _Dynamic problem._ System: superconfiguration including gas turbines, 2- and 4-stroke diesel engines, bottoming Rankine cycle, auxiliary boiler, and DG sets. Dynamic SDO optimization. Initially continuous and then discretized load profile. Mixed Integer Dynamic Optimization Problem (MIDO). Objective: maximize NPV. Algorithm: Direct sequential method combined with NLP solver implanted in gPROMS software. * [79] [PERSON]; [PERSON]; [PERSON] _Energy_**2019. ** System: DG sets, MCFCs, thermal boilers, WHR, and carbon capture technology in cruise ship with electric propulsion. Operation profiles for electric and thermal loads are considered. SD optimization. Load profiles are considered in the form of frequency of occurrence. Operation with predetermined rules. Two objectives: (i) minimize life cycle cost and (ii) minimize life cycle CO\({}_{2}\) emissions. Four scenarios are examined regarding the policy on CO\({}_{2}\). Algorithm: Nonsorting Genetic Algorithm NSGA-II. * [23] [PERSON]; [PERSON] _Journal of Engineering for the Maritime Environment_**2019. ** System: superconfiguration with 4-stroke diesel engines, DG sets, HRSG, steam turbine, and auxiliary boiler in LNG carrier. Dynamic SDO optimization.