This paper presents the multi-criteria single-objective optimization of an Organic Rankine Cycle (ORC) system, focusing on the Waste Heat Recovery (WHR) from marine main engine waste streams. The exhaust gas waste heat serves as the primary source for the ORC evaporator. Simultaneously, the cooling water loop of the main engine is directly employed to preheat the ORC working fluid. This study aims to identify a compact ORC heat exchangers design by minimizing the ratio of respective area to net power output under specific constraints in terms of evaporating and condensing conditions. In this context, the patternsearch function of MATLAB optimization toolbox [1] is implemented. The optimization process involves also computing this ratio by setting the net power output as the objective function. To determine the total plate heat exchanger area, a discretization method involving heat transfer correlations for singleand two-phase fluids is developed. The selected ORC working fluid for this investigation is R1233zd(E) as a promising low-GWP and non-flammable fluid, while there is also an intermediate loop for an indirect evaporation. The solutions obtained through the application of the patternsearch function indicate that a power output of 317 kW requires an area of 0.83 m2 kW−1 for plate heat exchangers per net power output. This area requirement doubles when aiming for a power output of 555 kW.     «

This paper presents the multi-criteria single-objective optimization of an Organic Rankine Cycle (ORC) system, focusing on the Waste Heat Recovery (WHR) from marine main engine waste streams. The exhaust gas waste heat serves as the primary source for the ORC evaporator. Simultaneously, the cooling water loop of the main engine is directly employed to preheat the ORC working fluid. This study aims to identify a compact ORC heat exchangers design by minimizing the ratio of respective area to...     »