Energy Systems Engineering / Enerji Sistemleri Mühendisliği

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

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Now showing 1 - 7 of 7

Citation - WoS: 1
Citation - Scopus: 2
Analysis and Application of Advanced Control Strategies To a Heating Element Nonlinear Model
(IOP Publishing Ltd., 2017) Turhan, Cihan; Simani, Silvio; Zajic, Ivan; Gökçen Akkurt, Gülden; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
This paper presents the design of different control strategies applied to a heating element nonlinear model. The description of this heating element was obtained exploiting a data-driven and physically meaningful nonlinear continuous-time model, which represents a test-bed used in passive air conditioning for sustainable housing applications. This model has low complexity while achieving high simulation performance. The physical meaningfulness of the model provides an enhanced insight into the performance and functionality of the system. In return, this information can be used during the system simulation and improved model- based and data-driven control designs for tight temperature regulation. The main purpose of this study is thus to give several examples of viable and practical designs of control schemes with application to this heating element model. Moreover, extensive simulations and Monte- Carlo analysis are the tools for assessing experimentally the main features of the proposed control schemes, in the presence of modelling and measurement errors. These developed control methods are also compared in order to evaluate advantages and drawbacks of the considered solutions. Finally, the exploited simulation tools can serve to highlight the potential application of the proposed control strategies to real air conditioning systems.
Citation - WoS: 11
Citation - Scopus: 13
Assessment of Thermal Comfort Preferences in Mediterranean Climate a University Office Building Case
(Vinca Inst Nuclear Sci, 2018) Turhan, Cihan; Gökçen Akkurt, Gülden; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
This study aims at evaluating the perceived thermal sensation of occupants with respect to thermal comfort standards, ASHRAE 55 and ISO 7730, for office buildings located in Mediterranean climate. A small office building in Izmir Institute of Technology Campus Area, Izmir, Turkey, was chosen as a case building and equipped with measurement devices to assess thermal comfort of occupants with respect to predicted mean vote and actual mean vote. Both objective and subjective measurements were conducted. The former included indoor and outdoor air temperature, mean radiant temperature, relative humidity and air velocity that were used for evaluating the thermal comfort of occupants. Oxygen concentration which can play an additional role in thermal comfort/discomfort, health and productivity of the office occupants, was also measured. Furthermore, occupants were subjected to a survey via a mobile application to obtain subjective measurements to calculate actual mean vote values. Based on objective and subjective measurements, the relationships among the parameters were derived by using simple regression analysis technique while a new combined mean vote correlation was also derived but this time by using multiple linear regression model. Neutral and comfort temperatures were obtained using indoor air temperature and actual mean vote values which were calculated from subjective measurements. The results showed that neutral temperature in the university office building was 20.9 degrees C whilst the comfort temperature range was between 19.4 and 22.4 degrees C for the heating season. By applying new comfort temperatures, energy consumption of the case building located in Mediterranean climate, can be reduced.
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; 01. Izmir Institute of Technology; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering
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.
Citation - WoS: 1
Citation - Scopus: 2
Feasibility of Large Scale Wind Turbines for Offshore Gas Platform Installation
(AIMS Press, 2018) Bingöl, Ferhat; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Although, offshore wind energy development emerged under way at the beginning of the millennium, Europe is planning to bring offshore wind energy capacity to over 11.6 GW until 2020. This is nearly 10 times todays installed offshore capacity and equal to nearly 50% of the new planned investment in the wind energy market. The North Sea and the Baltic Sea are the main investment areas due to the shallower sea depth. In this paper an approach to use old gas / oil platforms as the foundation for a wind turbine is examined. An off shore gas platform close to Istanbul Turkey with over 20 years more lifetime is taken as a real-life case, with the wind resource information extracted from the recent large-scale wind atlas study, Global Wind Atlas version 2. The study aims to combine recent offshore economical models with up-to-date scientific wind energy yield assessment models to have a more realistic look on the feasibility of such an approach. The results show that, with the assumption of no extra support structure and capital loan costs, a project can be feasible with bigger then 8MW wind turbines. These may involve a large initial investment but the return of the investment (ROI) can be as low as 8 years. With bigger turbines, profit can be increased, and ROI can be decreased while the Levelized Cost of Energy (LCOE) displays minor decrease after 10 MW.
Citation - WoS: 7
Citation - Scopus: 7
The Importance of Internal Heat Gains for Building Cooling Design
(Yıldız Teknik Üniversitesi, 2017) Coşkun, Turgay; Turhan, Cihan; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden; 02.02. Department of Architecture; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology; 02. Faculty of Architecture
This paper aims to investigate the effect of internal heat gains on the cooling load of a building. The house occupied by three adult men is selected as the case study for paper. The house is in the third floor of the apartment. The apartment has four flats and it has no insulation around the external walls. The heat dissipation from lighting devices, electrical equipment and the occupants are calculated by using the DesignBuilder v4 Beta release simulation program. The temperature of the house is observed during three weeks by using hobo data loggers and calibration of the measurements is made with respect to weather data file of the flat. Detailed schedule based on time of operation and occupancy is prepared to get more accurate results. Annual energy consumption and cooling load of the house is determined by using the dynamic simulation program.
Citation - WoS: 7
Citation - Scopus: 8
Performance Indices of Soft Computing Models To Predict the Heat Load of Buildings in Terms of Architectural Indicators
(Yıldız Teknik Üniversitesi, 2017-08) Turhan, Cihan; Kazanasmaz, Zehra Tuğçe; Gökçen Akkurt, Gülden; 02.02. Department of Architecture; 03.10. Department of Mechanical Engineering; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology; 02. Faculty of Architecture
This study estimates the heat load of buildings in Izmir/Turkey by three soft computing (SC) methods; Artificial Neural Networks (ANNs), Fuzzy Logic (FL) and Adaptive Neuro-based Fuzzy Inference System (ANFIS) and compares their prediction indices. Obtaining knowledge about what the heat load of buildings would be in architectural design stage is necessary to forecast the building performance and take precautions against any possible failure. The best accuracy and prediction power of novel soft computing techniques would assist the practical way of this process. For this purpose, four inputs, namely, wall overall heat transfer coefficient, building area/ volume ratio, total external surface area and total window area/total external surface area ratio were employed in each model of this study. The predicted heat load is evaluated comparatively using simulation outputs. The ANN model estimated the heat load of the case apartments with a rate of 97.7% and the MAPE of 5.06%; while these ratios are 98.6% and 3.56% in Mamdani fuzzy inference systems (FL); 99.0% and 2.43% in ANFIS. When these values were compared, it was found that the ANFIS model has become the best learning technique among the others and can be applicable in building energy performance studies.
Citation - WoS: 1
Citation - Scopus: 1
Thermodynamic Re-Assessment of a Geothermal Binary Power Plant Operated in a Moderate-Temperature Geothermal Field
(Inderscience, 2023) Özcan, Zeynep; Gökçen Akkurt, Gülden; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
An existing organic rankine cycle power plant which uses isobutane as working fluid is re-evaluated for different working fluids. The plant is first modelled by EES software; then the model is simulated for different working fluids obtaining heat transferred through the heat exchanger, net work output, energy and exergy efficiencies, and mass flowrate of the working fluid. Two parametric studies are conducted to evaluate the thermodynamic performance of the plant under a range of turbine inlet temperature (130°C–155°C) and geothermal resource temperature (152°C–161°C) for each working fluid. The study reveals that the highest cycle energy and exergy efficiencies are observed for R-152a at any geothermal resource temperature. R-152a resulted with 13.1% and 58.2% cycle energy and exergy efficiency, respectively at operation condition, whilst the lowest efficiency and net work output is calculated under n-butane presence.

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