Browsing by Author "Sogut, M. Ziya"

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Citation - Scopus: 3
Concept mapping sustainable energy management for a holistic approach to energy strategies
(INDERSCIENCE ENTERPRISES LTD, 2016) M. Ziya Sogut; Murat Pasa Uysal; Yavuz Gazibey; Arif Hepbasli; Hepbasli, Arif; Sogut, M. Ziya; Gazibey, Yavuz; Uysal, Murat Pasa
One of the important reasons for global warming and climate change is regarded as the improper management of fossil energy consumption. There may be various models or approaches to energy management (EM). However strategic EM and its applications are still away from achieving their goals. In this regard the main objectives of the present study are to design develop and propose a knowledge framework primarily based on an EM concept map for a holistic EM. Aligned with the research purposes a qualitative four-phase study was conducted and the research question was formulated as: 'What would be the components and concepts required for the holistic EM?' The study also integrated systematic literature review (SLR) and focus group discussion (FGD) techniques. Initially a list of the key EM concepts was formed and a preliminary concept map was constructed. Then the final version of the concept map was achieved through several iterative revisions and FGDs. This concept map may be seen as a complementary and contributory tool for strategy development and decision-making processes in the EM knowledge domain. It is hoped that the study may extend the previous knowledge both by the tools it has utilised and approaches it has adopted for the holistic EM
Citation - Scopus: 2
Investigating the exergetic and environmental effects of subcooling and superheating processes on the performance of direct expansion systems
(Springer International Publishing, 2014) M. Ziya Sogut; Hikmet Tahir Karakoc; Zuhal Oktay; A. Hepbasli; Oktay, Zuhal; Hepbasli, Arif; Sogut, M. Ziya; Karakoç, Hikmet
Recently subcooling and superheating applications which are proposed as an approach for the efficient use of energy have positive effect on the emission next to increasing the energy efficiency. This study examines energetic exergetic and environmental effects of subcooling and superheating processes in cooling applications separately. In this study a direct expansion system(DX) which is usedwidely in supermarket cooling applications is taken into consideration. The evaporator temperatures of −25 °C and 0 °C the refrigerants of R-22 R-404A and R-134a which are preferred widely in DX systems and minimum and maximum leakage rates of 3 and 30 % are taken as reference values for the analysis. According to the results while subcooling and subheating processes increase approximately 10 % of COP and exergy efficiencies based on refrigerants and decrease CO2 emissions for all refrigerants. The study also concluded with an emphasis on the importance of subcooling and superheating applications especially for DX systems and the importance of the preference refrigerant. © 2017 Elsevier B.V. All rights reserved.