This research introduces and optimizes a novel multi-generation power system integrating a steam Rankine cycle (SRC), a gas turbine (GT), an absorption refrigeration cycle (ARC), a proton exchange membrane (PEM) electrolyzer, and a CO2 separation unit. This system is designed to improve energy efficiency while simultaneously capturing CO2 and producing hydrogen through electrolysis. Two configurations-with and without ARC-are evaluated using a genetic algorithm-based multi-objective optimization framework, which considers exergetic efficiency, CO2 emission reduction, and total cost rate. The findings demonstrate that the proposed system improves exergetic efficiency by up to 71% and reduces CO2 emissions by up to 3.9% compared to a standalone GT system. Furthermore, the system without ARC achieves higher hydrogen production, while the system with ARC provides valuable cooling. These findings demonstrate the feasibility and environmental advantages of integrated power, CO2 capture, and H 2 blending systems for sustainable energy generation.
Carbon dioxide (CO2) has emerged as a promising natural refrigerant for electric vehicle (EV) heat pump systems because of its low environmental impact and strong heating capability at low ambient temperatures. However, its high operating pressure, low critical temperature, and transcritical behavior continue to hinder practical vehicle implementation. This review critically examines recent developments in CO2-based heat pump systems for EV thermal management, covering key components, advanced cycle configurations, and auxiliary performance-enhancement strategies. Unlike previous reviews that focused mainly on general CO2 systems or EV heat pumps using multiple refrigerants, the present study provides a dedicated synthesis of CO2-based EV heat pump technologies from an EV-oriented system-level perspective. Advanced configurations, including dual heat exchangers, secondary loops, ejector cycles, vapor injection, intercooled compression, and auto-cascade systems, are reviewed together with waste heat recovery, operating control, refrigerant mixtures, and defrosting strategies. The reviewed evidence indicates that advanced cycle configurations can improve low-temperature heating capability, reduce compressor burden, and expand the operating range, while auxiliary technologies can enhance energy utilization, adaptability, and operational stability. However, these benefits are frequently accompanied by increased packaging requirements, control complexity, cost, and reliability concerns. Therefore, the selection and integration of CO2 heat pump technologies should account for the trade-offs between thermodynamic performance and practical vehicle implementation under different operating conditions. This review provides a structured technical basis for developing high-efficiency and reliable CO2-based thermal management systems for next-generation EVs.
