Thermo-economic evaluation and multi-objective optimization of an integrated solar-aided system for hydrogen, power, and biodiesel production with algal-based carbon capture

Abstract

The demand for energy, along with the increase in population, and environmental pollution prompts the world community to produce renewable and new fuels using advanced technologies at the lowest cost. The current work analyzes a groundbreaking multi-generation system that integrates solar energy and methane combustion to simultaneously produce electricity power, hydrogen, thermal energy, and biofuel. The system features a solar power tower, an organic and a steam Rankine cycle, a proton exchange membrane electrolyzer, supercritical carbon dioxide, and two additional Brayton cycles. The utilization of waste heat to warm the water supplied to the hydrogen generation unit and feeding the carbon dioxide to the algae cultivation environment is crucial, as it not only enhances biofuel production but also effectively contributes to carbon capture, underscoring the system’s dual role in promoting sustainability and resource efficiency. Findings indicate that this system can yield a net power output of 19,194 kW. Notably, the solar system and combustor exhibit the highest rates of exergy destruction and total capital expenditure. Additionally, the multi-generation system is optimized using a multiobjective genetic algorithm, which aims to enhance energy efficiency while minimizing product costs and exergy destruction rates. The optimization results show a thermal efficiency of 55.68%, a total system cost rate of 0.080624$/hour, and exergy destruction of 71,422 kW.