Multi-objective optimization of a combined cooling, heating and power system integrated with reformed methanol high-temperature proton exchange membrane fuel cell

Reformed methanol high-temperature proton exchange membrane fuel cell (RM HT-PEMFC) systems demonstrate potential for both mobile and stationary applications. However, optimizing key variables is challenging due to the complex coupling of heat flows across various temperature levels. This study develops a combined cooling, heating and power system by integrating the RM HT-PEMFC with a double-effect LiBr-H2O absorption refrigeration cycle. The proposed system is optimized using the Non-dominated Sorting Genetic Algorithm II (NSGA-II), targeting system exergy efficiency, specific CO2 emissions, and exergy cost per unit product. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is employed to determine the optimal values of objectives: an exergy efficiency of 43.12%, specific CO2 emissions of 0.510 kg/kWh, and exergy cost per unit product of 167.59 USD/GJ, representing improvements of 20.73%, reduction of 17.10%, and 1.07% compared to baseline. The optimized ranges for key parameters are identified as follows: stack temperature (173.94-179.91 degrees C), steam to carbon ratio (1.78-1.80), current density (0.20-0.40 A/cm2), and cathode stoichiometry (2.29-2.52).