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A new configuration of solar energy-driven integrated system for ammonia synthesis and power generation is proposed in this study. A detailed dynamic analysis is conducted on the designed system to investigate its performance under different radiation intensities. The solar heliostat field is integrated to generate steam that is provided to the steam Rankine cycle for power generation. The significant amount of power produced is fed to the PEM electrolyser for hydrogen production after covering the system requirements. A pressure swing adsorption system is integrated with the system that separates nitrogen from the air. The produced hydrogen and nitrogen are employed to the cascaded ammonia production system to establish increased fractional conversions. Numerous parametric studies are conducted to investigate the significant parameters namely; incoming beam irradiance, power production using steam Rankine cycle, hydrogen and ammonia production and power production using TEGs and ORC. The maximum hydrogen and ammonia production flowrates are revealed in June for 17th hour as 5.85 mol/s and 1.38 mol/s and the maximum energetic and exergetic efficiencies are depicted by the month of November as 25.4% and 28.6% respectively. Moreover, the key findings using the comprehensive dynamic analysis are presented and discussed. • A new solar energy driven integrated system for ammonia synthesis is proposed. • A detailed modelling is conducted on the solar-assisted cascaded ammonia synthesis. • The additional heat from ammonia synthesis is recovered using thermoelectric generators. • Maximum H 2 and NH 3 flowrates are found in 17th hour of June as 5.85 and 1.38 mol/s. • Maximum energetic and exergetic efficiencies are found in Nov as 25.4% and 28.6%. [ABSTRACT FROM AUTHOR]

A novel configuration of hybrid wind-solar PV based cascaded ammonia synthesis is proposed in this article. A comprehensive dynamic analysis is conducted in this study which is substantial to explore the system functionality under different atmospheric conditions as the power achieved by the wind farm source is dependent on the wind speed and power extracted from the solar PV source depends upon solar radiation intensities. The system is designed to supply the electrical output extracted from the wind-solar PV sources to the proton exchange membrane electrolyser after meeting the system work requirements for hydrogen production. The produced hydrogen reacts with nitrogen separated from pressure swing adsorption to synthesize ammonia. A cascaded ammonia synthesis system is employed in this study to achieve high fractional conversion and simulated using Aspen Plus V11. Toronto is chosen as the geographical location for the dynamic simulation. The minimum exergetic efficiency is found to be 19.21% during the month of December and maximum exergetic efficiency is determined as 26.06% during the month of April. Similarly, the minimum energetic efficiency is found to be 18% during December and maximum energetic efficiency was determined as 24.42% during the month of April. In addition, the results obtained from comprehensive dynamic analyses are presented and discussed. • A novel hybrid wind-solar PV based cascaded ammonia synthesis is proposed. • A comprehensive dynamic analysis is conducted to explore the system functionality. • Toronto is chosen as the geographical location for dynamic simulations. • The maximum efficiency is determined for the month of April. [ABSTRACT FROM AUTHOR]

• A biomass and solar energy based system is developed and comparatively evaluated. • The proposed system is analysed thermodynamically by energy and exergy approach. • Hydrogen, electricity, hot water for fish farming and cooling are major commodities. • The hydrogen production rate of 59.45 mol/s and power of 8.3 MW is produced. • The overall energy and exergy efficiencies are found to be 29.9% and 31.5%. A biomass and solar energy based system consisting of a gas turbine cycle, a reheat Rankine cycle, a solar heliostat field, four-step copper-chlorine cycle and absorption cooling system is newly proposed, analyzed and comparatively evaluated through energy and exergy approaches. The proposed system is designed for the multiple useful commodities of hydrogen, electricity, hot water for fish farming and cooling. The effects of different operating conditions and parameters, namely air flow rate, biomass flow rate, working fluid flow rate, direct normal irradiance, number of heliostats, evaporator exit temperature and ambient temperature are investigated for the performance of the designed system defined in terms of energy and exergy efficiencies, and energy and exergetic coefficients of performance. The combined system, excluding solar heliostat field and absorption cooling system, is simulated using the Aspen Plus while the subsystems are modeled using the engineering equation solver package. Heating and cooling are produced for community usage, and hydrogen can be employed for industrial purposes. Both design and cost analyses are also conducted using the Aspen Plus v9 and Aspen Plus economic analyzer v9. The energy efficiency of the overall system is determined as 29.9% while the corresponding exergy efficiency is obtained to be 31.5%. The additional findings and outcomes are also presented and discussed comprehensively. [ABSTRACT FROM AUTHOR]

This paper presents an innovative use of waste heat recovered from a cement slag for multigeneration purposes, including power, ammonia, heat, hot water and oxygen production. A novel approach of ammonia production is employed in this study. The proposed system consists of four major subsystems; copper-chlorine (Cu-Cl) cycle, cryogenic Air Separation Unit (ASU), ammonia synthesis reactor and two steam Rankine cycles. The Aspen plus 9.0 version is employed for modeling and simulation of the proposed system. A comparative study is also conducted considering the different CuCl cycle based integrated systems for multigenerational purpose with numerous energy sources. The parametric studies are carried out by varying parameters, namely flow rate, compressor and turbine discharge pressures and ammonia reactor conversion rate. The exergy analysis is comprehensively conducted for each of the system components through exergy balance equations and exergy efficiencies. The overall exergy efficiency of the designed system is found to be 36.1%. Further results are also presented and discussed. • An innovative use of waste heat recovery for ammonia and power production. • Power, ammonia, heat, hot water and oxygen production are system outputs. • Ammonia production rate of 13 mol/s and electric power of 3422 kW is achieved. • The overall exergy efficiency of the designed system is found to be 36.1%. [ABSTRACT FROM AUTHOR]

Abstract This paper examines the performance and viability of a cement slag waste heat recovery system combined with a thermochemical copper-chlorine cycle for hydrogen production combined with hydrogen compression and a reheat Rankine cycle. The waste heat from the cement slag is recovered as a heat source for high-temperature reactions in the copper-chlorine cycle. The clean hydrogen production from waste heat recovery is examined with respect to both energy and exergy efficiencies. The integrated system is simulated and modeled in Aspen Plus. The multigeneration system utilizes the industrial waste heat and significantly reduces operating costs from the waste heat recovery. The overall energy efficiency of the integrated system is obtained as 32.5% while the corresponding exergy efficiency becomes 31.8%. Highlights • A new approach for clean hydrogen production via waste heat recovery. • Hydrogen and electricity are the two major outputs of the designed system. • The compressed H 2 production rate of the system is 19.6 mol/s. • The system overall energy and exergy efficiencies are 32.5% and 31.8%, respectively. [ABSTRACT FROM AUTHOR]

Abstract The thermochemical Cu Cl cycle has received greater attention by numerous researchers during the past decade as a promising hydrogen production method because of some operational advantages. The present paper analyzes three different configurations of the Cu Cl thermochemical cycle, namely three, four and five step ones thermodynamically. Some comparative parametric studies are conducted in order to investigate the overall energy and exergy efficiencies of the cycles considered. The Aspen plus is the software tool employed for the modeling and simulation of the cycles. The energy and exergy efficiencies of the five-step CuCl cycle are found to be 38.8% and 70.2% while the three-step CuCl cycle has an energy efficiency of 39.6% and an exergy efficiency of 68.1%, respectively. On the other hand, the four-step CuCl cycle provides the highest energy and exergy efficiencies of 41.9% and 75.7%. A parametric study is also conducted to investigate the effect of varying ambient temperature on the exergy efficiencies of all three cycles. The present study results further reveal that the cycle performance can be enhanced by improving the thermal management and reducing the exergy destructions. Highlights • Comparative assessment of the three different Cu Cl cycles for hydrogen production. • Numerous factors for heat and work requirements, operating conditions and exergy destructions are considered for analysis. • Aspen plus software tool is employed for the simulations of the cycles. • Four-step CuCl cycle offers the highest energy and exergy efficiencies. [ABSTRACT FROM AUTHOR]

Abstract A solar-wind hybrid trigeneration system is proposed and analyzed thermodynamically through energy and exergy approaches in this paper. Hydrogen, electricity and heat are the useful products generated by the hybrid system. The system consists of a solar heliostat field, a wind turbine and a thermochemical copper-chlorine (Cu-Cl) cycle for hydrogen production linked with a hydrogen compression system. A solar heliostat field is employed as a source of thermal energy while the wind turbine is used to generate electricity. Electric power harvested by the wind turbine is supplied to the electrolyzer and compressors and provides an additional excess of electricity. Hydrogen produced by the thermochemical copper-chlorine (Cu-Cl) cycle is compressed in a hydrogen compression system for storage purposes. Both Aspen Plus 9.0 and EES are employed as software tools for the system modeling and simulation. The system is designed to achieve high hydrogen production rate of 455.1 kg/h. The overall energy and exergy efficiencies of the hybrid system are 49% and 48.2%, respectively. Some additional results about the system performance are obtained, presented and discussed in the paper. Highlights • Analysis of a solar, wind and hydrogen hybrid trigeneration system. • A novel system of an integrated solar and wind source with the Cu-Cl cycle. • The three commodities of hydrogen, electricity and heat are produced. • Energy and exergy analyses are conducted for the integrated system. • The overall energy and exergy efficiencies are 49% and 48%, respectively. [ABSTRACT FROM AUTHOR]

A novel multi-generation integrated energy system is presented in this paper, consisting of a gas-steam combined cycle, four-step thermochemical copper-chlorine (Cu Cl) cycle, proton exchange membrane fuel cell (PEMFC) and a reverse osmosis (RO) desalination unit. Effective thermal management of waste heat is recognized as a key objective in the steel industry. Hydrogen, electricity, fresh water and heat are the useful outputs of the integrated system. The produced electricity supplies the electricity load required by the electrolyzer, compressor and pumps while the supplementary electricity is an additional system product. Aspen Plus and Engineering Equation Solver (EES) are used for modeling and simulation of the multi-generation system. The overall hydrogen production rate of the designed system is 51.8 kg/hr and the net power production is 1.7 MW. The overall energy efficiency of the multi-generation system is 63.3% and the exergy efficiency is 58.8%. Further sensitivity studies and outcomes are presented and discussed in this paper. [ABSTRACT FROM AUTHOR]

A novel integrated system for the production of hydrogen at a high pressure utilizing steel furnace waste heat is presented and analyzed in this paper. The system utilizes a hybrid thermochemical copper-chlorine (Cu-Cl) cycle. This study integrates the industrial waste heat source with the thermochemical Cu-Cl cycle combined with a hydrogen compression system. The electrical energy required by the system is provided by a supporting Rankine cycle. The hydrogen compression system compresses hydrogen to a pressure of 750 bars. The integrated system is simulated with Aspen Plus software. Energy and exergy analyses are performed for the integrated system. Results from the simulations are presented and discussed. The overall energy efficiency is 38.2% and overall exergy efficiency is found to be 39.8%. [ABSTRACT FROM AUTHOR]

Although there has been the commercially employed and widely used Haber-Bosch ammonia synthesis process which requires the high operating pressure and temperature in addition to the relatively low conversion rates, there is a need for a more compact and modular, but more efficient and effective approach. In conjunction with this, the present study develops, tests and investigates a cascaded ammonia synthesis system to explore the room for improvement in the ammonia conversion efficiencies. A lab-scale prototype is developed to investigate the effect of cascading two ammonia synthesis reactors in series employing pre-reduced KMR catalyst and the experimental investigations revealed the improved ammonia synthesis rates using cascaded configuration. The scanning electron microscopy (SEM) results of the KMR catalyst are also presented at different magnifications of 2.00 kx and 50.0 kx. The Aspen Plus simulation results of the cascaded ammonia synthesis system have also been validated using the experimental results and validation shows the percentage difference ranging from 1.62–6.61%. The experimentally developed cascaded ammonia synthesis system is investigated under different operating temperatures and pressures. The experimental results revealed that the ammonia conversion efficiencies that range from 4.58–7.88% using the single reactor with pressure rise from 6 to 12 bar at the temperature of 370 °C, increase to the conversion efficiencies of 5.42–9.16% by employing cascaded ammonia synthesis design. [Display omitted] • A new concept of cascaded ammonia synthesis is developed experimentally. • The experimental system performance is investigated with and without cascading. • The SEM results of KMR catalyst are presented at 2.00kx and 50.0kx magnifications. • Pressure rise from 6 to 12 bar increased NH3 conversion efficiencies from 5.42–9.16%. • The validation showed the percentage difference ranging from 1.62–6.61%. [ABSTRACT FROM AUTHOR]

This study presents a novel configuration using the hydrogen-natural gas and ammonia-natural gas blends for practical applications and investigates the system performance comprehensively. Natural gas is blended with hydrogen and ammonia to investigate performance improvement. Wind energy source is employed to the proposed configuration for power generation using wind turbines. The power generated by the wind turbine is employed to the proton exchange membrane (PEM) electrolyser for hydrogen production. A part of hydrogen is employed to the PEM fuel cell for power production. The proposed system is used to investigate the effect of hydrogen and ammonia blends with natural gas to achieve better performance. In order to investigate the H 2 -CH 4 blends, a part of the produced hydrogen is supplied to the mixing chamber from the hydrogen storage tank while ammonia input is supplied to the mixing chamber to improve the performance under NH 3 -CH 4 blends. The results revealed that the combustion energy and exergy efficiencies increase from 84.8% to 94.8% and 62.5%–70.2% respectively and the overall energetic and exergetic efficiencies increase from 37.4% to 40.3% and 36.8%–39.8% respectively with hydrogen addition from 0 to 20%. In the case of ammonia-natural gas blends, the combustion energy and exergy efficiencies increase from 84.8% to 92.9% and 58.9%–64.4% respectively and overall energetic and exergetic efficiencies increase from 37.4% to 39.1% and 36.8%–38.5% respectively. • This study presents wind energy based novel system for combustion applications. • Natural gas is blended with H 2 and NH 3 to investigate the performance improvement. • In H 2 and NH 3 blends with CH 4 , the H 2 and NH 3 fractions are taken from 0% to 20%. • Combustion efficiencies increases with NH 3 addition. • Overall efficiencies increase with NH 3 addition. [ABSTRACT FROM AUTHOR]

• Improvement capability of ammonia fuel cells tested with hydrogen inclusion. • Thermodynamic energy and exergy analyses performed with different fuel blends. • Energy efficiency rises by 7.9% with 40% hydrogen addition. • Exergy efficiency rises by 7.6% with 40% inclusion as compared to pure ammonia. In this study, hydrogen is investigated as a source of performance improvement for alkaline electrolyte entailing direct ammonia fuel cells via dual fuel utilization. Membrane electrolytes are utilized with anion exchange characteristics and the fuel cell performance is investigated with pure ammonia, ammonia-hydrogen blends and pure hydrogen. The power density is observed to be 1990.8 mW/m2 for pure ammonia fuel at peak point. However, this is found to increase to 2853 mW/m2 and 4471 mW/m2 when fuel blends of 80%NH 3 -20%H 2 and 60%NH 3 -40%H 2 are utilized respectively. The exergy efficiency at the maximum point power density increases from 14.2% to 22.1% and the energy efficiency rises from 15.2% to 22.8% as the fuel input is changed from pure ammonia to 60%NH 3 -40%H 2 by mass. Also, the highest exergy efficiency of 29.1% and energy efficiency of 28.7% is obtained for the pure hydrogen fueled cell. In addition, the exergy destruction rate is determined to be 16.8 mW for the pure ammonia fuel cell at the maximum point power density, which decreases to 15.1 mW and 13.6 mW for 60%NH 3 -40%H 2 and 80%NH 3 -20%H 2 fuels respectively. [ABSTRACT FROM AUTHOR]