Energy Systems Engineering / Enerji Sistemleri Mühendisliği
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Book Part Citation - Scopus: 4Investigation of a New Methanol, Hydrogen, and Electricity Production System Based on Carbon Capture and Utilization(Springer, 2023) Khani, Leyla; Mohammadpourfard, MousaIt is well-known that clean energy transition requires low carbon emission. The increase in population, economic development, and human welfare demands has led to a rise in energy consumption, mainly supplied by fossil fuels. However, burning fossil fuels produces carbon dioxide, which is a greenhouse gas and a contributor to environmental problems. Therefore, carbon capture and conversion to different products have gained attention. On the other hand, combining two or more different thermodynamic systems for simultaneous production of various demands from one energy source looks reasonable. In this regard, a new trigeneration system is proposed to decrease atmospheric carbon dioxide emission and produce methanol, hydrogen, and power. A flue gas stream with a defined composition, solar energy, and atmospheric air are the system’s inlets. Then, mass, energy, and exergy balance equations are applied for each subsystem to investigate the system’s thermodynamic performance. Also, the effect of changing operating parameters on the performance of each subsystem is studied. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.Book Part Citation - Scopus: 1A New Stable Solar System for Electricity, Cooling, Heating, and Potable Water Production in Sunny Coastal Areas(Springer, 2023) Khani, Leyla; Mohammadpourfard, MousaNowadays, more attention is paid to provide clean energy products with low environmental pollution in a decentralized way. Many coastal rural areas suffer from freshwater and electricity scarcity, especially in hot weather condition. Meanwhile, these regions have a great access to intense solar radiation and seawater. Hence, it seems logical to use the available solar energy in those places to provide to necessities like power, heating, and cooling. A new solar cooling, power, heating, and freshwater production system is designed, evaluated, and optimized in this research. The proposed system is composed of several subsystems to generate each product with high efficiency and reliability. Solar energy is unavailable at night, so molten salt energy storage is used to establish the steady operation of the system. Then, the system is evaluated from thermodynamic and exergoeconomic viewpoints, and a parametric study is accomplished to study the effect on the system performance of key variables. In the end, the system is optimized to determine its best operating condition for different cases. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.Article Citation - WoS: 7Citation - Scopus: 7Comprehensive Thermoeconomic Study of a New Solar Thermosyphon-Assisted Multigeneration System(Elsevier, 2023) Anamaq, Rasoul Najafi; Khani, Leyla; Mohammadpourfard, Mousa; Heris, Saeed Zeinali; Gökçen Akkurt, GüldenNowadays, due to the global energy crisis, limited reservoirs of fossil fuels, and their negative environmental effects, the use of renewable energy sources and multigeneration systems have become good alternatives for conventional thermodynamic systems. One of these resources, whose technology has developed rapidly in recent years, is the use of solar energy for the simultaneous generation of various products. Therefore, in this research, a multigeneration system with several subsystems is introduced. The proposed system includes a solar energy collector to receive thermal energy, two thermal energy storage tanks, an organic Rankine cycle, and a Kalina cycle to generate electricity, a multi-effect distillation unit to produce fresh water, an electrolyzer to produce hydrogen, as well as heat recovery for hot water and hot air generation. In this multigeneration system, the cooling unit is designed with the help of a thermosyphon. The performance of the proposed system is studied from energy, exergy, environmental, and exergoeconomic viewpoints using Aspen HYSYS and EES software. The obtained results show that due to the addition of the thermosyphon unit to the refrigeration system, the exergy efficiency increases from 55.62% to 70.26%. As a result of this combination, the performance of the whole system is improved and the amount of costs are reduced. In addition, the parabolic collector system has the highest exergy destruction ratio, 39%, among the subsystems. Furthermore, the results of the exergoeconomic analysis indicate that the PEM water heater with 33.3% and the ejector with 22.7% own the highest cost destruction rates.Article Citation - WoS: 26Citation - Scopus: 25Biomass Driven Polygeneration Systems: a Review of Recent Progress and Future Prospects(Elsevier, 2023) Tabriz, Zahra Hajimohammadi; Khani, Leyla; Mohammadpourfard, Mousa; Gökçen Akkurt, GüldenBiomass is the most widely used renewable energy source which is highly appreciated due to its high availability and non-intermittent nature. Considering problems such as reduction of fossil fuels, global warming, and emission of greenhouse gases, lack of attention to the existing situation may cause irreversible damage to the future of the planet. In addition to using renewable energy sources, improving the efficiency of systems will also be helpful. Polygeneration systems play an important role in increasing efficiency and reducing pollution. So, the use of biomass in polygeneration systems seems to be a great approach for sustainable development. Recent studies on biomass-based polygeneration systems have focused on how to use biomass and integrate diverse subsystems to achieve the best performance from energy and exergy viewpoints. The present paper reviews biomass-based systems, and the parameters affecting the performance of these systems. The literature review shows that the high exergy destruction rate in the gasifiers is the most frequent problem among recent articles. In addition, despite the advantages of anaerobic digestion process, the number of studies conducted on the use of this method for biomass conversion is small. In the end, results, limitations, and future outlooks of these systems are discussed.Article Citation - WoS: 9Citation - Scopus: 10Energy and Exergy Analysis of Combined Power, Methanol, and Light Olefin Generation System Fed With Shale Gas(Elsevier, 2022) Khani, Leyla; Tabriz, Zahra Hajimohammadi; Mohammadpourfard, Mousa; Gökçen Akkurt, GüldenEnvironmental problems and limitations of fossil fuel resources, especially crude oil, have intensified the importance of using cleaner and cheaper fuels besides enhancing energy conversion processes. Therefore, a novel power, methanol, and light olefin multi-generation system is designed and modeled in this paper. Chemical looping reforming, chemical looping combustion cycles, and Rankine power system are combined with methanol and light olefin production processes. The input fuel of the system is shale gas. The mass, energy, and exergy balance equations are applied for each system unit as a steady-state control volume to assess its thermodynamic operation. Then, the effects on the system performance of critical parameters are studied comprehensively. The results show that the necessary syngas can be supplied when 71.5% of the inlet shale gas is used in the steam reforming reactor of the chemical looping reforming cycle, and the steam to fuel ratio and carbon dioxide to fuel ratio are 0.61. Furthermore, if 31% of the produced methanol is consumed in the olefin production unit, the system energy and exergy efficiencies are achieved at 67.3% and 71.5%, respectively. In this case, the carbon dioxide flow rate is 800 kmol/hr, separated and stored in the chemical looping combustion cycle, leading to a clean thermodynamic system.Article Citation - WoS: 38Citation - Scopus: 40Exergoeconomic Analysis and Optimization of a High-Efficient Multi-Generation System Powered by Sabalan (savalan) Geothermal Power Plant Including Branched Gax Cycle and Electrolyzer Unit(Elsevier, 2022) Seiiedhoseiny, Miryasin; Khani, Leyla; Mohammadpourfard, Mousa; Gökçen Akkurt, GüldenEmploying suitable subsystems to reach high efficiency and low cost in renewable-based power plants is more crucial. The geothermal energy heat source is located in many countries, but this has never been investigated to run a multi-generation system, including a branched GAX cycle and an electrolyzer. In this path, a high-efficient multi-generation system powered by a Sabalan (Savalan) geothermal power plant consisting of a single flash cycle, a branched GAX cycle, and an electrolyzer is presented and scrutinized from thermodynamic and exergoeconomic viewpoints. In the end, a two-objective optimization, by using the Total Unit Cost of Product (TUCP) and energy efficiency as objectives, is utilized to find the optimum operating conditions. Critiques and studies of variables reveal that the produced hydrogen rate remains unchanged at 5.655 kg/h by changing the degassing value and temperature of the generator, condenser 2, and evaporator. By increasing the flash tank pressure from 5.2 bar to 7 bar, the cooling and heating loads rise about 108.4%, while the net electricity falls from 3977 kW to 3506 kW. Interestingly, the TUCP has a minimum value at the evaporator temperature of 273 K and condenser 2 temperature of 322.3 K. The optimization results indicate the values of the produced hydrogen rate and net electricity with 5.85 kg/h and 4187 kW are more than those of the base case. Also, the optimal values are 7.046 $/GJ, 36.82%, and 65.42% for the TUCP and energy and exergy efficiencies, respectively.Article Citation - WoS: 19Citation - Scopus: 20Multi-Objective Optimization of a Novel Supercritical Co2 Cycle-Based Combined Cycle for Solar Power Tower Plants Integrated With Sofc and Lng Cold Energy and Regasification(Wiley, 2022) Taheri, Muhammad Hadi; Khani, Leyla; Mohammadpourfard, Mousa; Aminfar, Habib; Gökçen Akkurt, GüldenThis study presents a new system for solar power, which is generated through a solar power tower with a molten salt cycle. To increase the consumption of energy losses, besides the closed supercritical carbon dioxide (sCO2) Brayton cycle, a liquid natural gas (LNG) open-cycle was used as a heat sink alongside a cascade organic Rankine cycle with the capability of working at low temperatures. LNG is implemented for a solid oxide fuel cell input, after cooling down the power generation systems and power generation. Besides the economic and thermodynamic analysis, destruction of exergy has been controlled and parametric studies are performed to investigate the influence of relative factors on the performance of the system. To optimize the system, a genetics algorithm has been employed by considering two reciprocal objective functions of the total cost rate and the exergy efficiency. The results of multi-objective optimization show that the optimized point has a total product cost rate of $115.3/h and an exergy efficiency of 71%. Furthermore, exergy analysis shows that the molten salt heat exchangers and the LNG heat exchangers have the maximum rates of irreversibility and must be taken into consideration as a major priority for optimization.Article Citation - WoS: 6Citation - Scopus: 8Thermodynamic Design, Evaluation, and Optimization of a Novel Quadruple Generation System Combined of a Fuel Cell, an Absorption Refrigeration Cycle, and an Electrolyzer(Wiley, 2022) Khani, Leyla; Mohammadpour, Mahsa; Mohammadpourfard, Mousa; Heris, Saeed Zeinali; Gökçen Akkurt, GüldenIn this article, a solid oxide fuel cell system is combined with a generator absorber heat exchanger absorption refrigeration cycle and a proton exchange membrane electrolyzer unit to use most of the fuel energy and recover waste heat and material. This quadruple-generation system produces electric power, refrigeration, heating, and hydrogen from natural gas as the primary energy source for the system. The thermodynamic and environmental performances of the system are studied comprehensively to identify the effects of the key operating parameters on the system operation. The results show that as fuel cell current density increases from 2000 to 8000 A/m2; the system energy and exergy efficiencies decrease by nearly 20%, but the unit carbon dioxide emission increases by 30.38%. Also, the energy and exergy efficiencies are maximized, and the unit carbon dioxide emission is minimized at a specified value of fuel utilization factor. Additionally, increasing the steam to carbon ratio has a damaging effect on the system efficiencies but leads to higher unit carbon dioxide emission. Then, the genetic algorithm is applied to optimize the condition, so the highest exergy efficiency is attainable. The optimization results demonstrate that an exergy efficiency as high as 0.6443 is achievable.Article Citation - WoS: 59Citation - Scopus: 67Design and Thermodynamic Analysis of a Novel Methanol, Hydrogen, and Power Trigeneration System Based on Renewable Energy and Flue Gas Carbon Dioxide(Pergamon-Elsevier Science LTD, 2021) Nazerifard, Reza; Khani, Leyla; Mohammadpourfard, Mousa; Mohammadi-Ivatloo, Behnam; Gökçen Akkurt, GüldenIn this paper, a new trigeneration system is proposed to decrease atmospheric carbon dioxide emission and produce methanol, hydrogen, and power. The system is composed of an organic Rankine cycle, a direct methanol fuel cell, a carbon capture unit, a proton exchange membrane electrolyzer, and a methanol synthesis unit. A flue gas stream with a defined composition, solar energy, and the atmospheric air are the system?s inlets. In the design step, special attention is paid to heat and mass integration between different components so that its waste can be lowered as much as possible. Then, mass balance law, energy conservation principle, exergy relations, and auxiliary equations are applied for each subsystem to investigate the system's thermodynamic performance. Also, the effect of changing operating parameters on the performance of each subsystem is studied. The obtained results show that the proposed system has the energy and exergy efficiencies of 66.84% and 55.10%, respectively. Furthermore, 94% of the total exergy destruction rate belongs to the water electrolyzer, while the contribution of the organic Rankine cycle is negligible. The performance of the methanol synthesis reactor depends strongly on its inlet temperature. Maximum equilibrium methanol concentration and carbon dioxide conversion are achieved at the inlet temperature of 210 degrees C. The parametric studies reveal that there is an optimum fuel cell current density in which its produced power density is maximized.