Energy Systems Engineering / Enerji Sistemleri Mühendisliği

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Access Right: Closed AccessAuthor: search.filters.author.Gökçen Akkurt, Gülden

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  • Article
    Citation - WoS: 12
    Citation - Scopus: 13
    Integration of Psychological Parameters Into a Thermal Sensation Prediction Model for Intelligent Control of the Hvac Systems
    (Elsevier, 2023) Turhan, Cihan; Özbey, Mehmet Furkan; Lotfi, Bahram; Gökçen Akkurt, Gülden
    Conventional thermal comfort models take physiological parameters into account on thermal comfort models. On the other hand, psychological behaviors are also proven as a vital parameter which affects the thermal sensation. In the literature, limited studies which combine both physiological and psychological parameters on the thermal sensation models are exist. To this aim, this study develops a novel Thermal Sensation Prediction Model (TSPM) in order to control the HVAC system by considering both parameters. A data-driven TSPM, which includes Fuzzy Logic (FL) model, is developed and coded using Phyton language by the authors. Two physiological parameters (Mean Radiant Temperature and External Temperature) and one psychological parameter (Emotional Intensity Score (EIS) including Vigour, Depression, Tension with total of 32 subscales) are selected as inputs of the model. Besides the physiological parameters which are decided intentionally considering a manual ventilated building property, the most influencing three sub- psychological parameters on thermal sensation are also selected in the study. While the physiological parameters are measured via environmental data loggers, the psychological parameters are collected simultaneously by the Profile of Mood States questionnaire. A total of 1159 students are participated to the questionnaire at a university study hall between 15th of August 2021 and 15th of September 2022. The results showed that the novel model predicted Thermal Sensation Vote (TSV) with an accuracy of 0.92 of R2. The output of this study may help to develop an integrated Heating Ventilating and Air Conditioning (HVAC) system with Artificial Intelligence – enabled Emulators that also includes psychological parameters. © 2023 Elsevier B.V.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Energy and Exergy Analysis of a Geothermal Energy Sourced Hot-Air Drying System
    (Inderscience Enterprises, 2023) Helvacı, Hüseyin Utku; Keleş, Nazlı; Gökçen Akkurt, Gülden
    A geothermal energy-sourced drying system was tested for the thin-layer drying process of tomato slices at air temperatures of 40 degrees C, 50 degrees C and 60? and velocities of 0.5 m/s and 1.5 m/s to investigate system performance in terms of the first and second laws of thermodynamics. The energy and the exergy efficiency of the system were found to be 6.6% and 22.31%. The energy utilisation and energy utilisation ratio were calculated in the range of 1.271 kW-5.102 kW and 9.644%-39.56%, respectively. The exergy destruction, exergy efficiency and improvement potential of the drying chamber varied between 0.0198 kW-0.2621 kW, 59.74%-81.95% and 0.00486 kW-0.07396 kW, respectively.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Comprehensive Thermoeconomic Study of a New Solar Thermosyphon-Assisted Multigeneration System
    (Elsevier, 2023) Anamaq, Rasoul Najafi; Khani, Leyla; Mohammadpourfard, Mousa; Heris, Saeed Zeinali; Gökçen Akkurt, Gülden
    Nowadays, 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: 49
    Citation - Scopus: 51
    Energy, Exergy, Exergoeconomic, and Exergoenvironmental (4e) Analysis of a New Bio-Waste Driven Multigeneration System for Power, Heating, Hydrogen, and Freshwater Production: Modeling and a Case Study in Izmir
    (Elsevier, 2023) Tabriz, Zahra Hajimohammadi; Mohammadpourfard, Mousa; Gökçen Akkurt, Gülden; Heris, Saeed Zeinali
    Today, the world is facing numerous challenges such as the increasing demand for energy, fossil fuels reduction, the growth of atmospheric pollutants, and the water crisis. In the present research, a new multigeneration system based on urban sewage bio-waste has been designed and evaluated for power, hydrogen, freshwater, and heating production. This system, which consists of biomass conversion subsystem, hydrogen production unit, Brayton cycle, atmospheric water harvesting unit, steam Rankine cycle, and organic Rankine cycles, has been evaluated from a thermodynamic point of view, and the energy, exergy, exergoeconomic, and exergoenvironmental analyses have been carried out on it. In the current study, the atmospheric water harvesting unit, as an attractive and environmentally friendly technology, is integrated with this Biomass-based multigeneration. A case study has been conducted on this system using the information collected from cigli wastewater treatment plant located In Izmir province, Turkey, and the results indicate that such a system, in addition to receiving sewage sludge from the treatment plant unit as a polluting waste, can produce added value products. The modeling results show that in the base conditions and with a feed rate of 7.52 kg/s, the total power generated by this system is 17750 kW, the hydrogen production rate is 3180 kg/h, the freshwater production rate is more than 18 l/h, and the energy and exergy efficiencies are 35.48% and 40.18%, respectively. According to the exergoeconomic and exergoenvironmental evaluations, the unit cost of total products and the unit emission of carbon dioxide are calculated as 13.05 $/GJ and 0.2327 t/MWh, respectively. Also, the results of parametric studies show that increasing the rate of Biomass improves the overall energy efficiency and production rates and also reduces the unit emission of carbon dioxide, but on the other hand, it causes a decrease in exergy efficiency and an increase in the unit cost of total products.
  • Article
    Citation - WoS: 59
    Citation - Scopus: 67
    Design 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, Gülden
    In 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.
  • Article
    Citation - WoS: 20
    Citation - Scopus: 23
    Thermal Comfort Analysis of Historical Mosques. Case Study: the Ulu Mosque, Manisa, Turkey
    (Elsevier, 2021) Diler, Yusuf; Turhan, Cihan; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden
    Mosques are sanctuary places for Muslims where they can perform their religious activities and also can communicate with each other. On the other hand, historical mosques may contain artworks which have cultural heritage values. These mosques originally have not any Heating, Ventilating and Air Conditioning systems. For this reason, obtaining thermal comfort becomes a significant issue. In this study, a systematic approach on monitoring and evaluating thermal comfort of historical mosques were developed. As a case study, The Ulu Mosque, Manisa/Turkey was monitored from 2015 to 2018, and thermal comfort evaluation of the mosque was conducted during prayer times based on the method provided by ISO 7730. A dynamic Building Energy Performance Software, DesignBuilder, was used to model the mosque, and the model was calibrated by using hourly indoor temperature data. The calibrated model was then used to evaluate existing conditions of the mosque and develop retrofitting scenarios in order to increase thermal comfort of prayers. Thirteen different scenarios were proposed to improve thermal comfort of prayers during worship periods. The results were evaluated according to EN 16883 for conservation of cultural heritage of the mosque. Electrical radiator heating with intermittent operating schedules was obtained as the best scenario to protect cultural heritage via artworks, while decreasing disssatisfaction level of the prayers from 45% to 10% in winter months. Additionally, intermittent operation saved 46.9% of energy compared to continuous operating schedule. (C) 2021 Elsevier B.V. All rights reserved.