Browsing by Author "Dincer I."
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Item Investigation of the energetic and exergetic performance of the Gonen geothermal district heating system(2006) Ozgener L.; Hepbasli A.; Dincer I.This article describes a performance evaluation of the Gonen geothermal district heating system (GGDHS) in Balikesir, Turkey on the basis of energy and exergy analyses. The case study covers the actual system data taken from the GGDHS in Balikesir, Turkey. General energy and exergy analyses of the geothermal district heating systems are introduced. Then, these analyses applied to the GGDHS using actual thermodynamic data for its performance evaluation in terms of energy and exergy efficiencies are presented. In addition, a parametric study on the effect of varying reference state properties on the energy and exergy efficiencies of the system that has been conducted to find the optimum performance and operating conditions is explained. In this article, the authors undertake a parametric study to investigate how varying reference temperature from 0 °C to 20 °C will affect the energy and exergy efficiencies of the GGDHS and develop two significant correlations (with a correlation coefficient of 0.99), which can be used for predicting the efficiencies. Two parametric expressions for energy and exergy efficiencies were developed as a function of the reference temperature. Both energy and exergy flow diagrams illustrate and compare the results under different conditions. For the actual system that is presented, the system energy and exergy efficiencies vary between 0.41 and 0.60 and 0.60 and 0.70, respectively. © IMechE 2006.Item Exergoeconomic analysis of geothermal district heating systems: A case study(2007) Ozgener L.; Hepbasli A.; Dincer I.; Rosen M.A.An exergoeconomic study of geothermal district heating systems through mass, energy, exergy and cost accounting analyses is reported and a case study is presented for the Salihli geothermal district heating system (SGDHS) in Turkey to illustrate the present method. The relations between capital costs and thermodynamic losses for the system components are also investigated. Thermodynamic loss rate-to-capital cost ratios are used to show that, for the devices and the overall system, a systematic correlation appears to exist between capital cost and exergy loss (total or internal), but not between capital cost and energy loss or external exergy loss. Furthermore, a parametric study is conducted to determine how the ratio of thermodynamic loss rate to capital cost changes with reference temperature and to develop a correlation that can be used for practical analyses. The correlations may imply that devices in successful district heating systems such as the SGDHS are configured so as to achieve an overall optimal design, by appropriately balancing the thermodynamic (exergy-based) and economic (cost) characteristics of the overall systems and their devices. © 2006 Elsevier Ltd. All rights reserved.Item A key review on performance improvement aspects of geothermal district heating systems and applications(2007) Ozgener L.; Hepbasli A.; Dincer I.This paper deals with a comprehensive analysis and discussion of geothermal district heating systems and applications. In this regard, case studies are presented to study the thermodynamic aspects in terms of energy and exergy and performance improvement opportunities of three geothermal district heating systems, namely (i) Balcova geothermal district heating system (BGDHS), (ii) Salihli geothermal district heating system (SGDHS), and (iii) Gonen geothermal district heating system (GGDHS) installed in Turkey. Energy and exergy modeling of geothermal district heating systems for system analysis and performance evaluation are given, while their performances are evaluated using energy and exergy analysis method. Energy and exergy specifications are presented in tables. In the analysis, the actual system operational data are utilized. In comparison of the local three district heating systems with each other, it is found that the SGDHS has highest energy efficiency, while the GGDHS has highest exergy efficiency. © 2006 Elsevier Ltd. All rights reserved.Item Parametric study of the effect of reference state on energy and exergy efficiencies of Geothermal District Heating Systems (GDHSs): An application of the Salihli GDHS in Turkey(2007) Ozgener L.; Hepbasli A.; Dincer I.A parametric study of the effect of reference state on the energy and exergy efficiencies of geothermal district heating systems is presented. In this regard, the work consists of two parts: a modeling study covering energy and exergy analysis and a case study covering the actual system data taken from the Salihli Geothermal District Heating System (SGDHS) in Manisa, Turkey. General energy and exergy analysis of the geothermal district heating systems is introduced along with some thermodynamic performance evaluation parameters. This analysis is then applied to the SGDHS using actual thermodynamic data for its performance evaluation in terms of energy and exergy efficiencies. In addition, a parametric study on the effect of varying dead state properties on the energy and exergy efficiencies of the system that has been conducted to find optimum performance and operating conditions is explained. Two parametric expressions of energy and exergy efficiencies were developed as a function of the reference temperature. Both energy and exergy flow diagrams illustrate and compare results under different conditions. It has been observed that the exergy destructions in the system particularly take place as the exergy of the fluid lost in the heat exchanger, the natural direct discharge of the system (pipeline losses), and the pumps, which account for 31.17%, 8.98%, and 4.27% of the total exergy input to the SGDHS, respectively. For the actual system that is presented, the system energy and exergy efficiencies vary between 0.53 and 0.73 and 0.58 and 0.59, respectively.Item Exergy analysis of two geothermal district heating systems for building applications(2007) Ozgener L.; Hepbasli A.; Dincer I.This study evaluates the exergetic performance of two local Turkish geothermal district heating systems through exergy analysis. The exergy destructions in these geothermal district heating systems are quantified and illustrated using exergy flow diagrams for a reference temperature of 1 °C using the 2003 and 2004 actual seasonal heating data. The results indicate that the exergy destructions in these systems particularly occur due to losses in pump, heat exchangers, pipelines, and the reinjection of thermal water. Exergy efficiencies of the two systems are investigated for the system performance analysis and improvement and are determined to be 42.89% and 59.58%, respectively. © 2006 Elsevier Ltd. All rights reserved.Item Analysis of some exergoeconomic parameters of a small wind turbine system(2009) Ozgener O.; Ozgener L.; Dincer I.This paper investigates some exergoeconomic parameters (energy and exergy loss ratios) for a 1.5 kW wind turbine system, linking capital costs and thermodynamic losses, based on some operating conditions. The results show that while the ratio of energy loss rate to capital cost (Ren) changes between 0.007 and 0.813 at different wind speeds, the ratio of exergy loss rate to capital cost (Rex) changes between 0.006 and 0.411. In addition, the maximum Ren and Rex values are obtained at a wind speed of 12 m/s. Furthermore, a parametric study is undertaken to investigate how varying wind speed will affect the exergoeconomic parameters of the wind turbine system and to develop a correlation between the ratio of thermodynamic loss rate to capital cost and wind speed for practical applications of wind energy systems.Item A new experimentally developed integrated organic Rankine cycle plant(Elsevier Ltd, 2021) Sorgulu F.; Akgul M.B.; Cebeci E.; Yilmaz T.O.; Dincer I.In this study, an organic Rankine cycle (ORC) integrated with a combustion subsystem and a horizontal belt-type drying unit is developed, built, and tested at a pilot scale for organic wastes to energy applications. The organic wastes used for experimental investigation are chicken manure collected from the respective food sector. A novel drying unit is also employed to dry out the chicken manure to the desired moisture level for more efficient and effective combustion. The heat generated is further supplied to the ORC for power generation. Finally, the heat rejected from ORC is used for chicken manure drying purposes. This way, the ORC generates two useful commodities like electricity and heat. An amount of 400 ton/day chicken manure from almost 4 million chickens is burned to obtain heat. The heat obtained from the combustor is utilized in an organic Rankine cycle with a capacity of 2.3 MW net power. The integrated ORC system is analyzed comprehensively through energy and exergy approaches, and its environmental impact assessment is performed. A detailed efficiency evaluation is carried out by considering energy and exergy efficiency approaches. The overall energy and exergy efficiencies of the integrated system are determined as 29.45% and 28.05%, respectively. For the ORC specifically, the energy and exergy efficiencies are calculated as 90.58% and 62.60% by considering the cycle as a cogeneration unit. © 2021 Elsevier Ltd