4E-based performance evaluation of a solar-assisted SOFC–CCHP system integrating zero-energy CO2 enrichment and cascade waste heat recovery

Abstract

To address the challenges of suboptimal solar energy utilization, energy-intensive CO₂ capture, and inefficient waste heat recovery, this study proposes a novel solar-assisted solid oxide fuel cell combined cooling, heating, and power system. The proposed architecture integrates: (1) a partially covered parabolic trough photovoltaic/thermal collector to preheat steam reforming water, reducing heat-exchanger exergy losses; (2) a water–gas shift membrane reactor simultaneously controls fuel gas composition and enriches CO₂ without additional energy input, achieving a 79.68 % emission reduction compared with conventional systems; and (3) a cascaded waste heat recovery process coupling a supercritical CO₂ Brayton cycle, an absorption chiller/heat pump, and heat exchangers to produce power, heating/cooling, and hot water. Comprehensive performance is assessed employing 4E (energy, exergy, environmental, economic) method. Under design conditions, the system attains cooling and heating energy efficiencies of 87.5 % and 95.7 %, respectively (boundaries include all thermal and electrical outputs), exergy efficiencies of 57.4 % and 58.5 %, a sustainability index of 1.68, a levelized cost of electricity of 0.0467 $/kWh, and a payback period of 4.82 years. Parametric analyses show that increasing SOFC operating temperature from 850 °C to 1100 °C and solar irradiance significantly enhances CO₂ mitigation and system efficiency. These results demonstrate that synergistic integration of renewable heat harvesting, in‐situ CO₂ capture, and cascading waste heat utilization can provide a high‐performance, low‐carbon solution for decentralized energy supply.