Browsing by Author "Kayfeci M."

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    Experimental investigations of using MWCNTs and graphene nanoplatelets water-based nanofluids as coolants in PVT systems
    (Elsevier Ltd, 2019) Alous S.; Kayfeci M.; Uysal A.
    In this study, a photovoltaic thermal collector)PVT(has been constructed in Karabuk University, Turkey to investigate the effects of utilizing multiwalled carbon nanotubes (MWCNT) and graphene nanoplatelets dispersed in water as a base fluid with a concentration of 0.5 wt% on the performance of PVT systems. Outdoor experiments were run with volume flow rate of 0.5 L/min for the aforementioned nanofluids and distilled water as a reference fluid. The study results, which were analyzed from energetic and exergetic viewpoints, have shown and revealed that the MWCNT-water nanofluid presented a better performance in terms of photovoltaic energetic conversion compared to graphene nanoplatelets-water nanofluid and distilled water, while graphene nanoplatelets-water nanofluid revealed the highest thermal energetic efficiency. Moreover adding thermal unit to photovoltaic module (PV) enhanced the total energetic efficiency by 53.4% for distilled water, 57.2% for MWCNT-water, and 63.1% for graphene-water. From the exergetic viewpoint, the increase in total exergetic efficiency was 11.2%, 12.1%, and 20.6% for PVT collector cooled by distilled water, MWCNT-water nanofluid, and graphene nanoplatelets-water nanofluid respectively. © 2019 Elsevier Ltd
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    EXPERIMENTAL STUDY ABOUT UTILIZATION OF MWCNT AND GRAPHENE NANOPLATELETS WATER-BASED NANOFLUIDS IN FLAT NON-CONCENTRATING PVT SYSTEMS
    (Serbian Society of Heat Transfer Engineers, 2021) Alous S.; Kayfeci M.; Uysal A.
    Although the increment the performance of photovoltaic thermal (PVT) systems by using the nanofluids as working fluids have gained the attention of researchers during the last two decades, there is still, a lack in the literature study associated to this application. This study contributes to the investigations and researches of applying the nanofluids to increase the performance of PVT collectors. A flat non-concentrating PVT collector has been designed, constructed and, outdoor tested in Karabuk University, Turkey. The considered working fluids in this study are multiwall carbon nanotubes (MWCNT), and graphene nanoplatelets dispersed in water as a base fluid with a concentration of 0.5 wt.%. The experiments were run with a volume flow rate of 0.5 L per minute for the aforementioned nanofluids and distilled water (as a reference fluid). The study results have shown and revealed that the MWCNT-water nanofluid presented a better performance in terms of electrical energetic efficiency compared to graphene nanoplatelets-water nanofluid and distilled water, while graphene nanoplatelets-water nanofluid revealed the highest thermal energetic efficiency. Moreover adding thermal unit to photovoltaic module enhanced the total energetic efficiency by 53.4% for distilled water, 57.2% for MWCNT-water, and 63.1% for graphene-water. © 2021. Society of Thermal Engineers of Serbia.
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    Futuristic methods of electronics cooling
    (Elsevier, 2023) Uysal A.; Keçebaş A.; Kayfeci M.
    Power density for high-performance chips has recently increased due to advancements in semiconductors, other mini- and micro-scale electronic technologies, and continued miniaturization. Heat is generated when the current passes over a resistance, and internal losses are unavoidable. Electronic devices produce heat this way while working. This heat needs to be taken from electronic devices due to its effect on their performance. The fault ratio on electronic devices increases exponentially as the temperature increases. That is how high operation temperature occurs from heat production on electronic devices that are not controlled and designed to cause safety and performance decreases. This reality is to make it necessary for heat transfer, namely, developing cooling systems and new investigations, and to increase the importance of thermal control on the operation and design parameters of electronic devices day by day. In this chapter electronic device cooling methods are classified as advanced cooling technologies (active and passive cooling methods) with the goal of guiding future research while representing current application areas. © 2023 Elsevier Inc. All rights reserved.