Energy Systems Engineering / Enerji Sistemleri Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4752

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Start date: 2002Publisher: search.filters.publisher.Wiley

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  • Article
    Citation - WoS: 29
    Citation - Scopus: 33
    The Effect of Heat Transfer Characteristics of Macromolecule Fouling on Heat Exchanger Surface: a Dynamic Simulation Study
    (Wiley, 2023) Karimi Shoar, Zahra; Pourpasha, Hadi; Zeinali Heris, Saeed; Mousavi, Seyed Borhan; Mohammadpourfard, Mousa
    At the city gate gas pressure reduction stations (CGSs), to prevent natural gas from forming a hydrate in the throttle valve, the natural gas is heated by the heater before reaching the pressure relief valve. Heat exchangers are an essential component of industrial processes that contribute significantly to total system energy. Since the element impacting heat exchanger performance is the fouling process, all fouling processes and models were dynamically simulated in this study. Through coding in the C++ language and simultaneous use of fluent functions, or, in other words, user-defined function (UDF), fouling-related models were defined for this software. The dynamic simulation was performed, and parameters such as fouling strength and layer thickness were calculated. The effects of changing operating conditions, such as gas inlet velocity, surface temperature, and fouling species concentration on fouling growth, were also evaluated. As the concentration of fouling species increased, the fouling rate also increased. The amount of supersaturation and fouling rate increased as the surface temperature increased. Due to the operational limitations of the system, to reduce the fouling rate, the gas inlet velocity should be as high as possible, and the fluid inlet temperature, surface temperature, and concentration of fouling species should be as low as possible. In this study, the required time to reach the efficiency of 70% of the heat exchanger was calculated using the modelling of this chamber, which was equivalent to 190 days. Additionally, the critical thickness of the fouling layer at this time was 3.5 cm.
  • Article
    Citation - WoS: 19
    Citation - Scopus: 20
    Multi-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, Gülden
    This 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: 6
    Citation - Scopus: 8
    Thermodynamic 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, Gülden
    In 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.