Membrane-based CO2 capture integrated with CCHP for a nearly zero-carbon building

Abstract

The present paper addresses the challenges of CO₂ emissions and energy efficiency in buildings by integrating a CO₂ capture and storage unit (CCSU) with a combined cooling, heating, and power (CCHP) system. The case study building used for evaluating the system was the School of Mechanical Engineering at the University of Tehran. The proposed system supplied the power, cooling, and heating demands of the building throughout the year and sold the excess electricity to the grid. The system comprised three subsystems: a gas turbine cycle as the prime mover, a molten-carbonate fuel cell combined with a heating system and chillers, and a Stirling engine combined with a membrane-based CCSU. The dynamic performance of the proposed system was assessed through a comprehensive 4E analysis (energy, exergy, economic, and environmental) using TRNSYS software. Multi-objective optimization techniques, including artificial neural networks and the non-dominated sorting genetic algorithm-II, were employed to determine the optimal size and operating conditions using MATLAB. The optimization ensured that the system operated at maximum efficiency while minimizing operational costs and CO₂ emissions. The results indicated a total cost rate of $55.29 per hour, an exergy efficiency of 44.96 %, and a significant reduction in CO₂ emission rate to 27.92 kg/h. The membrane-based CCSU reduced CO₂ emissions by up to 92 %, achieving the goal of a nearly zero-carbon building. The study highlights enhanced efficiency, financial viability, and environmental benefits of combining CCHP and CCSU, demonstrating its potential as a sustainable solution for reducing CO₂ emissions and promoting energy efficiency in buildings.