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A novel solar PV and wind energy based system is proposed in this study for capturing carbon dioxide as well as producing hydrogen, urea and power. Both Aspen Plus and EES software packages are employed for analyses and simulations. The present system is designed in a way that PEM electrolyzer is powered by the wind turbines for hydrogen production, which is further converted into ammonia and then synthesizes urea by capturing CO 2 and additional power is supplied to the community. The solar PV is employed to power the cryogenic air separation unit and the additional power is used for the industrial purpose. In the proposed system, ammonia does not only capture CO 2 but also synthesizes urea for fertilizer industry. The amount of electrical power produced by the system is 2.14 MW. The designed system produces 518.4 kmol/d of hydrogen and synthesizes 86.4 kmol/d of urea. Furthermore, several parametric studies are employed to investigate the system performance. • A novel solar-wind hybrid energy system is developed for hydrogen and urea production. • Produced hydrogen is converted into ammonia and synthesizes urea by capturing CO 2. • The amount of electrical power produced by the system is 2.14 MW. • Designed system produces 518.4 kmol/d of H 2 and synthesizes 86.4 kmol/d of urea. [ABSTRACT FROM AUTHOR]

Herein, a comparative energetic and life‐cycle assessment (LCA) study is performed on coal and natural gas‐based combined heat and power cogeneration plants. Different types of power plants, including gas turbine, steam turbine, and combined‐cycle plants, are considered. Three types of LCA methodologies, including CML 2001, TRACI, and ReCiPe, are used to analyze the life‐cycle environmental impacts of each plant. The coal‐based cogeneration plant is found to entail the comparatively lowest life‐cycle energy efficiency of 43.6%, and the natural gas‐based combined‐cycle cogeneration plant is found to have the highest efficiency of 59.6%. Furthermore, the coal‐based life cycle is also found to entail the highest life‐cycle environmental impacts comparatively. According to CML 2001, it entails a global‐warming potential of 0.229 kg CO2eq MJ−1 and an acidification potential of 7.03E‐4 kg SO2eq MJ−1. The natural gas‐fired boiler‐type cogeneration plant is observed to have a comparatively higher toxicity and eutrophication potential of 2.72E‐4 kg DCBeq MJ−1 and 2.78E‐5 kg PO4eq MJ−1, respectively. The lowest overall life‐cycle environmental impacts comparatively are found to be associated with the natural gas‐based combined‐cycle cogeneration plant. [ABSTRACT FROM AUTHOR]

In the present study, a new ammonia‐based system is developed and investigated as an energy storage option. In this regard, an environmentally benign cyclic synthesis and usage of ammonia is proposed. The proton exchange membrane‐based electrolysis is used for hydrogen generation with cyclic water usage and production. A direct ammonia fuel cell is employed for power generation. The performance of the developed system is investigated through both energetic and exergetic analyses. In addition, different phases of charging and discharging are considered during the energy storage operation. Furthermore, several parametric investigations are conducted to study the effects of changing operating conditions. The energy efficiency of the charging phase is found to be 41.1% and the exergy efficiency is evaluated to be 43.7%. Moreover, the energetic efficiency of the discharging phase is 78.1% while the exergetic efficiency is 73.4%. The overall efficiency of the system considering both charging and discharging phases is evaluated as 32.1%. [ABSTRACT FROM AUTHOR]

Summary: In this paper, we develop and experimentally investigate a novel hybrid ammonia fuel cell and thermal energy storage system. A molten alkaline salt is utilized for storing thermal energy as well as operating an alkaline electrolyte‐based direct ammonia fuel cell. The specific thermal energy storage capacity of the hybrid system is found to be 133 kJ kg−1 at a temperature of 320°C. Furthermore, the maximum power densities are found to be 2.1±0.1 W m−2 to 2.3±0.1 W m−2 for operating temperatures varying between 220°C and 320°C. The energy efficiency is evaluated as 20.6±0.6%, and the exergy efficiency is determined to be 23.3±0.7% at the peak power density. [ABSTRACT FROM AUTHOR]

Highlights • Development of novel hybrid ammonia fuel cell and battery system. • Regenerative-electrode to better utilize electrochemical energy. • Reversible fuel cell and battery potentials of 0.54 V and 0.73 V respectively. • Fuel cell energy and exergy efficiencies of 54.2% and 50.9% respectively. Abstract In the present study, a novel hybrid ammonia fuel cell and battery system is conceptually developed and studied electrochemically and thermodynamically. The novel system proposes a new method to enhance the utilization of electrochemical energy. The fuel cell cathode comprises of a regenerative nickel electrode. Ammonia is utilized as fuel at the fuel cell anode. During fuel cell operation, the half-cell electrochemical reaction at the cathode regenerates the electrode. This electrode acts as the anode during battery discharge. In addition, ammonia is formed at the battery cathode electrode, which is reused as fuel at the fuel cell anode. A performance assessment of the proposed system is conducted. The reversible potentials of the fuel cell and battery systems are evaluated as 0.54 V and 0.73 V respectively. The average energy and exergy efficiencies of the fuel cell system are obtained as 54.2% and 50.9% respectively. In addition, the efficiency of the battery system is found to be 75%. To analyse the system performance with changing operating conditions and parameters, several parametric studies are conducted. [ABSTRACT FROM AUTHOR]

In this study, we design and analyze a new solar tower based integrated system for desalination, electricity generation and hydrogen production. A reverse osmosis desalination system is incorporated into this integrated system. A proton exchange membrane (PEM) electrolyzer is also used for hydrogen production. A thermodynamic analysis through energy and exergy approaches is conducted to examine and assess the integrated system and its performance. The overall system energy efficiency is obtained as 23.2%. The overall system exergy efficiency is obtained to be 6.2%. In addition, the maximum energy and exergy efficiencies of the reverse osmosis desalination system are 60.3% and 30% respectively. The effects of changing system operating conditions and state properties on the efficiencies of system components and the overall system are also studied. The results of this study provide important inferences about the performance of the solar-based integrated system and the reverse osmosis desalination system. [ABSTRACT FROM AUTHOR]