1,720,968 research outputs found
Exergoeconomic analysis of photovoltaic thermal systems based on phase change materials and natural zeolites for thermal management
No full textConventional photovoltaic thermal (PVT) systems provide unstable thermal energy, which changes throughout the day. In PVT systems, phase change materials (PCMs) and heat storage materials could be used to make thermal energy more stable and provide longer-term thermal energy. In the present study, exergoeconomic analysis of PVT systems integrated with natural zeolites has been firstly carried out, and the results were compared with the results of PVT systems integrated with PCM and conventional one. PVT systems integrated with paraffin and stearic acid, common PCMs and conventional PVT systems were analyzed by specific exergy costing method, systems were compared exergoeconomically and suggestions were made to improve the economic performance of PVT systems. As a result of the analyzes conducted with 297 data obtained experimentally, the average energy efficiencies were calculated as 33%, 40%, 37% and 32% for paraffin, natural zeolite, stearic acid and conventional PVT system, respectively. Besides, average exergy efficiencies were 24%, 24%, 22% and 22% for paraffin, zeolite, stearic acid and conventional PVT system, respectively. The average entropy generation of the PVT based paraffin; natural zeolite, stearic acid and conventional one were found as 2.11, 2.29, 2.18 and 2.07 W K-1, respectively. According to the exergoeconomic analysis, specific exergy flow cost values were found as 0.206, 0.176, 0.204 and 0.206 euro kWh(-1) for the PVTs based on paraffin, natural zeolite, stearic acid and the conventional PVT. It was concluded that the natural zeolite-based PVT system was found as the best system exergoeconomically
Performance analysis of a novel concentrating photovoltaic combined system
No full textIn the present study, a novel Concentrating Photovoltaic Combined System (CPVCS) based on the spectral decomposing approach is introduced, modeled, tested experimentally and evaluated thermodynamically and economically. In this study, energy and exergy analyses of the system have been evaluated, economical analysis has been performed and the experimental results have been compared to data obtained by the control system. As a result, energy efficiencies of concentrator, vacuum tube and overall CPVCS have been determined to be 15.35%; 49.86%; and 7.3% respectively. Similarly the second law (exergy) efficiencies of concentrator, vacuum tube and overall CPVCS are 12.06%; 2.0%; and 1.16% respectively. The cost of energy production has been stated as 6.37 $/W and it is predicted that this value could be decreased by improving the system performance. © 2012 Elsevier Ltd. All rights reserved.110M008This study was carried out under the Scientific and Technological Research Council of Turkey (TUBITAK) 110M008 Project. The author would like to thank TUBITAK for their financial support
Energy, exergy, and economical analyses of a photovoltaic thermal system integrated with the natural zeolites for heat management
No full textIn this study, the first time in the literature, natural zeolite has been employed for photovoltaic thermal (PVT) and experimentally tested as a thermal energy storage material. The main aim of the paper is to introduce natural zeolite as a heat storage material for PVT systems. The PVT systems integrated with phase change materials and natural zeolite were designed, the components of the system were explained, the thermodynamical modelling including the first and second laws was presented, the system performances were evaluated, performance parameters were investigated, energy and exergy efficiencies were determined, and economical analyses of each system were performed. Besides, all results were compared with a conventional PVT system. The average overall energy efficiency values for PVT experiments were 33% for paraffin, 37% for stearic acid, 40% for zeolite, and 32% for conventional PVT systems. The payback period of the PVT system with paraffin, zeolite, stearic acid, and conventional PVT was calculated as 10, 8, 9, and 9 years, respectively. The results show that the natural zeolite is a material with significant potential to be used for heat management in PVT for any meteorological condition. © 2019 John Wiley & Sons, Ltd.Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, TÃœBITAKThis present work was developed within the framework of a research project having ID 214M615 fully funded by The Scientific and Technological Research Council of Turkey (TUBITAK). The author would like to thank TUBITAK for the financial support given to the projects
ORTAÖĞRETİM FEN ve MATEMATİK ALANLAR EĞİTİMİ LİSANSÜSTÜ PROGRAMLARINDA YAPILAN ARAŞTIRMALARIN DENEYSEL AŞAMALARINDA KARŞILAŞILAN GÜÇLÜKLER VE ÇÖZÜM ÖNERİLERİ
No full textExergoeconomic analysis of a novel concentrated solar energy for lighting-power generation combined system based on spectral beam splitting
No full textLighting-power generation combined system (LIPGECOS) based on the approach of spectral beam splitting of concentrating solar radiation was introduced and performed exergoeconomic analysis by well-known the Specific Exergy Costing (SPECO) method. From the experimental data, the average energy and exergy efficiencies of the LIPGECOS were calculated as 0.15 and 0.09 respectively. The cost flows for concentrating dish, fibre optic bundle (FOB), cold mirror and Stirling engine were calculated as 0.055, 0.018 in daily basis, respectively. The maximum exergetic cost coefficient belongs to the FOB component, while the minimum exergetic cost coefficient was calculated for the concentrating dish. Exergetic cost coefficients for the products of the dish, the mirror, the FOB and the Stirling engine are calculated as 1.07; 65.12; 199.47; 71.01 $/GJ, respectively. The maximum exergetic cost effectiveness (ECE) value is calculated for the dish as 0.1234; while the minimum one is for the mirror as 0.0000002. Copyright © 2016 Inderscience Enterprises Ltd
Güneşışığı ile çalışan aktif hibrit aydınlatma sisteminin tasarımı, kurulumu, testi ve performansa etki eden parametrelerin araştırılması
No full textPreface to the special section on "The 7th International Ege Energy Symposium and Exhibition (IEESE7)"
No full textWOS: 00036077220004
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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