Browsing by Author "Kecebas, Ali"

Now showing 1 - 2 of 2

Citation - WoS: 38
Citation - Scopus: 40
A comparative study on conventional and advanced exergetic analyses of geothermal district heating systems based on actual operational data
(Elsevier Science SA, 2013) A. Hepbasli; Ali Keçebaş; Hepbasli, Arif; Kecebas, Ali
This paper comparatively evaluates exergy destructions of a geothermal district heating system (GDHS) using both conventional and advanced exergetic analysis methods to identify the potential for improvement and the interactions among the components. As a real case study the Afyon GDHS in Afyonkarahisar Turkey is considered based on actual operational data. For the first time advanced exergetic analysis is applied to the GDHSs in which the exergy destruction rate within each component is split into unavoidable/avoidable and endogenous/exogenous parts. The results indicate that the interconnections among all the components are not very strong. Thus one should focus on how to reduce the internal inefficiency (destruction) rates of the components. The highest priority for improvement in the advanced exergetic analysis is in the re-injection pump (PM-IX) while it is the heat exchanger (HEX-III) in the conventional analysis. In addition there is a substantial influence on the overall system as the total avoidable exergy destruction rate of the heat exchanger (HEX-V) has the highest value. On the overall system basis the value for the conventional exergetic efficiency is determined to be 29.29% while that for the modified exergetic efficiency is calculated to be 34.46% through improving the overall components. © 2013 Elsevier B.V. © 2013 Elsevier B.V. All rights reserved.
Citation - WoS: 17
Citation - Scopus: 18
Comparing advanced exergetic assessments of two geothermal district heating systems for residential buildings
(Elsevier Ltd, 2014) Ali Keçebaş; Can Coskun; Zuhal Oktay; A. Hepbasli; Kecebas, Ali; Oktay, Zuhal; Coskun, Can; Hepbasli, Arif
Advanced exergy analysis method has been increasingly utilized in analyzing and assessing the performance of energy-related systems in recent years due to more deeply investigating the exergy destructions. In this study two various geothermal district heating systems (GDHSs) the Afyon and Bigadiç GDHSs which have been operated in Turkey were considered to perform their advanced exergy analyses and assessments. The GDHSs studied were also compared with each other for the first time in terms of advanced exergetic aspects. In the analyses and calculations of the GDHS the actual operational data obtained from the measurements and technical staff were utilized. The overall conventional and advanced exergetic efficiency values for the Afyon GDHS are determined to be 27.53% and 34.72% while those for the Bigadiç GDHS are obtained to be 21.03% and 32.52% respectively. Considering both the interactions among components and the potential for improving components more effective and efficient improvement priorities were proposed. © 2014 Elsevier B.V. © 2014 Elsevier B.V. All rights reserved.