Browsing by Subject "Energy storage unit"
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Item Energy and exergy analysis of a hybrid photovoltaic/thermal-air collector modified with nano-enhanced latent heat thermal energy storage unit(Elsevier Ltd, 2022) Selimefendigil F.; Şirin C.Electrical and thermal energy can be generated simultaneously by using photovoltaic-thermal (PVT) systems. Also, electrical efficiency can be enhanced by cooling the PV panel. In this study, three different PVT-air collectors have been designed, manufactured and experimentally analyzed including conventional (PVT), with paraffin-based thermal energy storage unit (PVT-TES) and with nano-enhanced paraffin-based thermal energy storage unit (PVT-NeTES). Copper oxide (CuO) nanoparticles (1 wt%) have been utilized to upgrade the thermal conductivity of the phase change material. Tests have been performed in two flow rates (0.007 and 0.014 kg/s). According to experimental results, overall exergy efficiencies for PVT, PVT-TES and PVT-NeTES were achieved between 10.52–13.59%, 11.08–14.36% and 12.52–15.44%, respectively. Moreover, sustainability index (SI) values were attained in the range of 1.12–1.16, 1.13–1.17 and 1.14–1.18, respectively. Obtained findings showed that utilizing nano-enhanced thermal energy storage system and increasing flow rate significantly upgraded both electrical and thermal performances of the PVT system. © 2021Item Experimental investigation of a parabolic greenhouse dryer improved with copper oxide nano-enhanced latent heat thermal energy storage unit(John Wiley and Sons Ltd, 2022) Selimefendigil F.; Şirin C.Solar dryers are clean and sustainable systems for preserving agricultural products. In this research, three different active greenhouse dryers, which are grouped in direct solar drying systems, have been designed, fabricated, and experimentally surveyed. Different from other works, this research contains an experimental investigation on nano-embedded thermal storage-assisted greenhouse drying system. Major goal of this study is to analyze the impact of utilizing nano-enhanced thermal energy storage unit on the performance of a greenhouse dryer. In this context, tunnel-type parabolic greenhouse dryers with paraffin wax thermal storage unit (PGD-TES) and nano-enhanced paraffin wax thermal storage unit (PGD-NeTES) have been tested and compared with a conventional parabolic greenhouse dryer (PGD). Copper oxide (CuO) nanoparticles have been employed to upgrade the thermal effectiveness of the thermal storage unit. Tests have been done in two flow rates, which are 0.009 and 0.014 kg/s. Utilizing nano-enhanced modification decreased drying time approximately between 35% and 58% in comparison to the conventional dryer. According to the results, average specific energy consumption values were attained in the ranges of 2.10 to 2.48, 1.93 to 2.09, and 1.63 to 1.89 kWh/kg, respectively, for PGD, PGD-TES, and PGD-NeTES. Also, exergy efficiency was improved by 36% by utilizing the nano-enhanced thermal energy storage system. © 2021 John Wiley & Sons Ltd.Item Experimental analysis of combined utilization of CuO nanoparticles in latent heat storage unit and absorber coating in a single-slope solar desalination system(Elsevier Ltd, 2022) Selimefendigil F.; Şirin C.; Öztop H.F.In this survey, impact of combined utilization of copper oxide (CuO) nanoparticles both in thermal energy storage unit and absorber coating (matt black paint) on the performance of a single-slope solar still has been investigated experimentally. In this context, four different solar desalination systems including a conventional solar still, solar still with thermal energy storage unit, solar still with CuO nano-embedded latent heat storage unit and solar still with CuO nano-enhanced absorber coating and thermal energy storage unit have been developed, fabricated and empirically analyzed. Experimental results showed that combined employing nanoparticles upgraded accumulated productivity as 26.77% in comparison to conventional solar still. Also, energy and exergy efficiency values were enhanced from 15.96% to 19.90% and from 1.25% and 2.01%, respectively with the use of combined modification. © 2022Item Enhancing the performance of a greenhouse dryer with natural dolomite powder-embedded latent heat thermal energy storage unit and air-to-air heat recovery system(Elsevier Ltd, 2023) Selimefendigil F.; Şirin C.Greenhouse drying systems (GDSs) are grouped in direct-type solar dryers and are widely utilised because of their easy applicability, high product drying capacity and cost-effectiveness. In the present work, it is aimed to improve the drying performance of a GDS by using natural dolomite powder-embedded latent heat thermal energy storage unit (LHTESU) and air-to-air heat recovery system (HRS). In this context, three different types of GDSs have been designed and manufactured including a GDS with paraffin-based LHTESU, a GDS with natural dolomite powder-embedded LHTESU and a HRS-assisted GDS with natural dolomite powder-embedded LHTESU. Designed and manufactured GDSs have been experimentally analysed under the same environmental conditions. According to the experimentally achieved findings, combined utilisation of HRS and dolomite powder in the LHTESU reduced the drying time approximately as 36.36%. Moreover, highest instantaneous outlet air temperature was achieved as 51.4 °C in the system that used natural dolomite-embedded LHTESU and HRS. The exergetic efficiency of the GDS was upgraded as 46.21% by using the mentioned modifications in comparison to the base case (the system contains only paraffin-based LHTESU). In addition, specific moisture extraction rate for the analysed GDSs was attained between 0.96 and 1.52 kg.kWh−1. © 2023 International Solar Energy SocietyItem EXPERIMENTAL ANALYSIS OF A SOLAR DESALINATION SYSTEM WITH GRAPHENE NANOPLATELET-EMBEDDED LATENT HEAT THERMAL ENERGY STORAGE UNIT(Begell House Inc., 2024) Şirin C.; Selimefendigil F.In the present work, it is aimed to improve the yield of a single-slope solar desalination system (SDS) using graphene nanoplatelet-embedded thermal energy storage unit (TSU). In the initial stage of this work, three SDSs with different slope angles of condensation surface including 40°, 50°, and 60° are considered. According to the result of the initial experiments, the SDS with 40° gave the superior performance. In the second part of the study, three different SDS configurations with 40° slope angle including a conventional SDS, an SDS with only paraffin-containing TSU, and an SDS with graphene nanoplatelet-embedded paraffin-containing TSU have been developed and tested under the same environmental conditions. According to the findings of the second experimental stage, utilizing only paraffin-containing and graphene nanoplatelet-embedded paraffin-containing TSUs in the conventional system with 40° slope angle improved the accumulated yield of the system as 11.85% and 26.96%, respectively. Also, energy and exergy efficiencies of the SDS with 40° slope angle were improved from 16.02% to 19.69% and from 1.36% to 2.13%, respectively, using the TSU with graphene nanoplatelets. The attained findings of this work clearly present the positive influence of employing graphene nanoplatelets in TSU of a single-slope SDS. © 2024 by Begell House, Inc.