Exergoeconomic and exergoenvironmental assessment of a geothermal-driven cogeneration system utilizing dual-pressure organic Rankine cycle and zeotropic mixtures

Abstract

In the current study, a detailed assessment and multi-objective optimization of a geothermal-driven cogeneration system for producing hydrogen and electricity have been carried out. The system includes two parts; the primary cycle is the geothermal cycle, which extracts geothermal energy. The secondary cycle consists of an organic Rankine cycle (ORC) and a proton exchange membrane (PEM) electrolyzer. In order to enhance ORC performance, zeotropic mixes have been used as working fluids. The concentration on the destructive environmental impacts of the system, which has not been considered in prior studies, is the research’s main novelty. This study mainly focuses on environmental evaluation using Life Cycle Assessment (LCA) to decrease destructive environmental impacts. From the perspectives of energy, exergy, exergoeconomic, and exergoenvironmental (4E), the pentane (0.3)-butane (0.7) working fluid performed better than other working fluids. Energy and exergy efficiency for the cogeneration system increased by 19.34% and 58.67%, respectively. According to the results of the exergoenvironmental analysis, the PEM showed significant product environmental consequences at a speed of 261 mpts/h. The multi-objective optimization findings illustrated that energy efficiency and destruction cost in optimum conditions reach 20.06% and 22.64 $/h. Furthermore, exergy efficiency and destruction environmental impacts will reach 59.81% and 1762.11 mpts/h, respectively.

Keywords

• Geothermal-based cogeneration
• Life Cycle Assessment (LCA)
• Hydrogen production
• Exergoeconomic evaluation