A novel 4E-based optimization framework for circular biomass multi-generation systems integrating NSGA-II and ANN to enhance resource efficiency and sustainability

Abstract

This study explores an innovative multi-generation energy system designed to improve resource efficiency and promote environmental sustainability. The proposed system relies on biomass as its primary energy source and integrates five main components: a gasification unit, a Brayton cycle, a Rankine steam cycle, an absorption chiller, and a multi-effect desalination unit with thermal vapor compression. Unlike conventional systems, this approach enables the simultaneous production of electricity, heating, cooling, and freshwater from a single renewable source, maximizing energy utilization while reducing carbon dioxide emissions. A comprehensive assessment was conducted from thermodynamic, economic, and environmental perspectives. The study identifies gasification and combustion as the major sources of exergy destruction, impacting overall system performance. To improve efficiency, a heat recovery unit was introduced, leading to a 37 % reduction in carbon dioxide emissions. The system was optimized using a multi-objective genetic algorithm, considering exergy efficiency, energy cost rate, and carbon emissions as key criteria. Under optimal conditions, the system achieved an exergy efficiency of 31.96 %, with compressor pressure ratio and combustion chamber temperature identified as the most critical factors influencing cost. In terms of energy production, the system generated 5830 kW of electricity, with 71 % derived from biomass and 29 % from the heat recovery unit. These findings highlight the potential of biomass-based multi-generation systems as a sustainable solution for addressing rising energy demands while reducing environmental impact.