Yazar "Tuncer, Azim Dogus" seçeneğine göre listele

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    A detailed investigation of the temperature-controlled fluidized bed solar dryer: A numerical, experimental, and modeling study
    (Elsevier, 2022) Gurel, Ali Etem; Agbulut, Umit; Ergun, Alper; Ceylan, Ilhan; Sozen, Adnan; Tuncer, Azim Dogus; Khanlari, Ataollah
    Solar thermal systems are generally utilized for providing sustainable and environmentally friendly thermal energy that can be used in different applications. In the present study, a temperature-controlled fluidized bed solar drying system along with flat plate and plate with zigzag fins has been designed, manufactured, and experimentally tested. In the first step, the thermal behavior of designed solar air collectors has been numerically modeled. In the next step, the drying system's performance has been experimentally investigated. The overall efficiency of the system was found to be 64%. The maximum exergy efficiency of flat and zigzag plate solar air collectors was calculated as 7.2% and 11.6%, respectively. Then moisture content (MC) and moisture ratio (MR) values were modelled by response surface methodology (RSM), and the predicted results were compared with four metrics. It was found that the drying parameters were highly fitted with the mathematical models. MC metric was predicted with accurate values for performance criteria of R-2, R-RMSE, and MBE as 0.9995, 1.94%, and -0.0096, respectively. The general outcomes of numerical, experimental and modeling analyses of this research exhibited successfulness of the developed the fluidized bed solar drying system.
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    AN EXPERIMENTAL INVESTIGATION TO PREDICT OPTIMUM CHARGE OF A HEAT PUMP SYSTEM
    (Begell House Inc, 2023) Afshari, Faraz; Khanlari, Ataollah; Tuncer, Azim Dogus; Soezen, Adnan
    Working principles of heat pumps is an important matter from a thermodynamic point of view that has been researched from various aspects. In this study, undercharged, optimum charged, and overcharged conditions of a heat pump were investigated using R134a refrigerant. Variations in temperature, pressure, and the coefficient of performance have been evaluated and it was aimed to find out the optimum charge condition considering different parameters. According to the experimentally obtained findings, the coefficient of performance was increased by more than three times when the refrigerant amount increased from 2000 g to similar to 7300 g. The general outcomes of the present study indicated that optimum refrigerant charge amount can notably affect the performance of heat pump apparatus. It was shown that the P-h diagram of all heat pump systems depends on the working conditions and the refrigerant charge is a very important criterion that can make significant changes in the P-h diagram. It was found that, by increasing refrigerant charge, after the downtrend starts in the compressor inlet temperature, 20% refrigerant can be added to achieve the maximum COP value. Additionally, the critical point in expansion valve outlet temperature was used to find the optimum charge. It was revealed that if 140% refrigerant is added to the given refrigerant at critical point, the optimum COP value can be achieved.
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    Analysis of a spiral-formed solar air heating system with ceria nanoparticles-enhanced absorber coating
    (Elsevier, 2023) Khanlari, Ataollah; Badali, Yosef; Tuncer, Azim Dogus
    Solar air heating systems are extensively applied in different applications in order to provide hot air using clean energy. In this study, a spiral type solar collector has been proposed, numerically simulated and manufactured. The main aim of this work is investigating the overall performance of a solar collector with spiral type absorber. In the first stage of this work, CFD approach has been used for simulating unbaffled and baffled spiral solar collector. Numerical findings exhibited better thermal performance of the baffled spiral collector. Therefore, in the following step of this survey, baffled spiral collector has been fabricated and experimentally analyzed at different conditions. In addition, ceria nanoparticles have been used in coating process of spiral-formed absorber plate of the system to upgrade the thermal efficiency. Mean thermal efficiency for spiral collector with and without nano-coating was obtained between 46.15 and 67.39%. Mean efficiency enhancement by using ceria nanoparticle coating in the tests made at 0.009 and 0.014 kg/s are 16.79% and 11.05%, respectively. Also, average exergy efficiency of spiral collector was achieved between 10.28 and 14.46%. Average sustainability index of spiral collector was gained in the range of 1.1151-1.1698. The overall findings of this study indicated successful utilization of the developed spiral type solar collector. Moreover, using ceria nanoparticle coating has significant positive effects on improving thermal efficiency of spiral collector. It can be concluded that the developed spiral type solar collector could be used in building integrated applications for providing fresh and heated air.
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    Analyzing the effect of flooring material type on the performance of an active greenhouse dryer
    (Elsevier, 2024) Tuncer, Azim Dogus; Khanlari, Ataollah
    In this work, the impact of flooring (bottom) material selection on the performance of an active greenhouse dryer (AGD) has been empirically surveyed. In this regard, four AGD configurations with different flooring materials including soil, gravel, sheet metal with conventional black paint and sheet metal with iron (Fe) nano-enhanced black paint have been designed, manufactured, and experimented at same fixed air flow rate. According to experimentally obtained findings, utilizing nano-enhanced black-painted sheet metal in the AGD instead of soil has a potential to almost double the average air temperature difference. Also, using sheet metal with nanoenhanced black paint reduced the drying periods as 41.17 %, 33.33 % and 20 %, respectively in comparison to the configurations that used soil, gravel and sheet metal with conventional matt black paint as bottom material. Average exergetic efficiencies for the tested configurations were obtained between the range of 3.22-11.14 %. Also, using sheet metal with Fe nano-enhanced absorber coating as a bottom material in the system reduced the carbon footprint as 32.66 % (from 1.50 to 1.01 kgCO2eq) in comparison to the system with soil bottom.
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    Application of carbon-based nanomaterials in solar-thermal systems: An updated review
    (Pergamon-Elsevier Science Ltd, 2024) Tuncer, Azim Dogus; Badali, Yosef; Khanlari, Ataollah
    Increasing the world population makes it necessary to look for alternative and sustainable energy resources to meet the rising energy demand. In recent years, the utilization of different renewable energies has been accelerated because of the negative effects of fossil fuels and their limited resources. Among different solar energy technologies, solar liquid and air collectors are extensively utilized for providing heated water and air. Rapid development in science and technology makes it possible to improve the performance of solar collectors. Producing nanomaterials and using the obtained nano-sized particles for improving the thermophysical specifications of the working fluid or coating material can be considered for performance improvement. In the present study, applications of carbon-based nanomaterials (CBNMs) in various solar thermal systems have been reviewed comprehensively. In other words, the effects of utilizing carbon-based nanomaterials as promising material on the overall performance have been investigated. Preparation techniques and thermophysical specifications of carbon-based nanomaterials have been explained in detail. Also, utilization of carbon-based nanomaterials in seven widely utilized solar-thermal technologies and their impacts on the thermal behavior of the tested system have been concluded. This review gives a general perspective about applicability of carbon-based nanomaterials for performance enhancement in various solar-thermal systems.
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    CFD analysis and experimental investigation to determine the flow characteristics around NACA 4412 airfoil blades at different wind speeds and blade angles
    (Sage Publications Ltd, 2023) Afshari, Faraz; Khanlari, Ataollah; Sozen, Adnan; Tuncer, Azim Dogus; Ates, Ibrahim; Sahin, Bayram
    An aerodynamically efficient blade is one of the prime necessities to extract the maximum mechanical power from a wind turbine. A number of researches are available in the literature studying blade design and configuration to improve aerodynamic characteristics of horizontal axis wind turbines. Less attention, however, has been devoted to wind turbines in terms of simultaneous optimization of blade and airfoil angles. The present study is important for the aerodynamic design and manufacturing of wind turbine blades. In this regard, various blade angles have been numerically simulated to determine the optimum blade angle. In addition to numerical analysis, experimental tests have been done to investigate NACA 4412 blade angle. As a result of this study, it was observed that blade angle in the range of 5 degrees-10 degrees showed the best performance among the tested various blade angles.
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    Comprehensive exergy analysis of dandelion root during physical pre-treatment by convective solar drying
    (Inderscience Enterprises Ltd, 2024) Moussaoui, Haytem; Chatir, Khaoula; Tuncer, Azim Dogus; Khanlari, Ataollah; Lamharrar, Abdelkader; Idlimam, Ali
    In this study, a controlled indirect solar dryer was used to dry dandelion roots at three temperatures of 60 degrees C, 70 degrees C, and 80 degrees C, together with two air flow rates of 0.0417 m(3)/s and 0.0834 m(3)/s. The main aim of this research is to carry out an exergetic analysis on the dryer chamber and the drying process in order to improve the exergetic efficiency of the solar dryer. The outcomes showed that the level of exegetic performance depends on the variation of the operating conditions. The exergy yield of the drying chamber of six drying configurations was obtained between the ranges of 48.1141%-68.2755%.
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    Developing an infrared-assisted solar drying system using a vertical solar air heater with perforated baffles and nano-enhanced black paint
    (Pergamon-Elsevier Science Ltd, 2023) Tuncer, Azim Dogus; Amini, Ali; Khanlari, Ataollah
    In the present study, it is aimed to improve the performance of a solar drying system (SDS) utilizing ZnO nano-enhanced absorber coating and infrared heating system. In the first stage of this work, different geometrical configurations of the main heating system of the SDS which is a vertical solar air heater (VSH) have been numerically analyzed. According to the numerical findings, VSH with perforated type baffles gave the best performance results. Then, the determined configuration has been manufactured and combined with a drying chamber. Moreover, two other modifications have been applied to the system including an infrared heater and nano-enhanced black paint. In other words, the experimental part of this research contains three SDS types including a conventional SDS, a SDS with infrared heater and a SDS with infrared heater and ZnO nano-enhanced absorber coating (combined usage of two modifications). The mean thermal and exergetic efficiencies of the VSH analyzed within the scope of this work were attained between 53.54-65.12% and 9.94-14.32%, respectively. Moreover, combined use of infrared heater and nano-enhanced absorber coating material in the VSH decreased the drying time period as 43.75% when compared to the unmodified SDS.
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    Energy and exergy analysis of a vertical solar air heater with nano-enhanced absorber coating and perforated baffles
    (Pergamon-Elsevier Science Ltd, 2022) Khanlari, Ataollah; Tuncer, Azim Dogus; Sozen, Adnan; Aytac, Ipek; Ciftci, Erdem; Variyenli, Halil Ibrahim
    In this work, the effect of applying nano-enhanced absorber coating on the energetic and exergetic performance of an unglazed vertical solar air heating system has been analyzed numerically and experimentally. In the first step of the research, various configurations of vertical solar air heaters including hollow, baffled and perforated baffled systems have been surveyed by using computational fluid dynamics. According to the numerically obtained findings, the system with perforated baffles gave the best performance metrics. In this regard, two heating systems with perforated baffles have been manufactured. One of the system was painted with a regular matt black paint while CuO nano-embedded black paint applied to the other solar heater. Fabricated heaters have been experimentally surveyed at three different flow rates. Thermal efficiency values for the heaters with and without nanoparticles were found between 58.10-76.22% and 54.96-72.05%, respectively. Applying nano-embedded coating increased the exergy efficiency in the range of 9.25-10.58%. In addition, maximum deviation of numerically and experimentally attained outlet temperature values was calculated as 4.74%. Moreover, general findings of this research showed the successful utilization of nano-enhanced absorber coating. (C) 2022 Elsevier Ltd. All rights reserved.
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    EXPERIMENTAL ANALYSIS OF A QUADRUPLE-PASS SOLAR AIR HEATER WITH EXTENDED HEAT TRANSFER SURFACES AND NANO-ENHANCED ABSORBER COATING
    (Begell House Inc, 2023) Khanlari, Ataollah; Tuncer, Azim Dogus
    In recent years, selective solar absorber surface coating applications have become quite popular in terms of enhancing the thermal performance of solar-thermal systems. Generally, nano-sized particles with high thermal conductivity values are preferred to be utilized in this type of modifications. In this study, nanoparticle-enhanced absorber coating material was applied to a quadruple-pass solar air heater to improve the thermal performance. In this regard, copper oxide nanoparticles with 38-nm average particle size and 32.9 W/m K thermal conductivity were mixed with industrial matte-black paint (2% wt./wt.). The obtained mixture was then applied to the heater and the developed heater has been experimented at three flow rate values. Embedding nanoparticles to the pure paint improved the average thermal conductivity as 0.033 W/m K (from 0.6392 W/m K to 0.6722 W/m K). According to the experimentally attained outcomes, mean thermal efficiency values were obtained in the range of 71.27-79.63%. Improving the flow rate from 0.007 kg/s to 0.013 kg/s enhanced the sustainability index value from 1.1696 to 1.2123. Moreover, maximum instantaneous thermal efficiency was found to be 4.05% higher in comparison with the system without nano-enhanced modification which was tested in a previous work.
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    Experimental and numerical analysis of a grooved hybrid photovoltaic-thermal solar drying system
    (Pergamon-Elsevier Science Ltd, 2023) Tuncer, Azim Dogus; Khanlari, Ataollah; Afshari, Faraz; Sozen, Adnan; Ciftci, Erdem; Kusun, Baris; Sahinkesen, Istemihan
    Photovoltaic-thermal (PVT) systems are sustainable applications that allows to produce thermal and electrical energies simultaneously. In this work, a sustainable solar drying system that contains a modified PVT-air collector has been designed, numerically analyzed, manufactured and tested. In the first step of this study, four different PVT collector configurations have been numerically analyzed in order to develop a new hybrid PVT drying system. According to the numerically obtained results, outlet temperature of the PVT collector with grooved absorber, spherical turbulators and baffle configurations was higher than the outlet temperature of the unmodified collector as 15.77 %. This promising PVT collector was then fabricated and integrated with a drying chamber. The manufactured hybrid drying system has been tested under various air flow rates. The experimental findings illustrated that the average thermal efficiency and overall exergy efficiency of the PVT collector varied between 61.32 and 77.49 % and 10.65-11.17 %, respectively. In addition, mean exergy efficiency of the drying chamber was found in the range of 59.16-68.31 %. Average sustainability index values of the collector and the drying chamber was obtained between the ranges of 1.12-1.14 and 3.74-5.82, respectively. Moreover, payback period of the dryer varied between 2.98 and 3.51 years according to the economic analysis.
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    Experimental and numerical analysis of a helically-coiled solar water collector at various angular placements
    (Elsevier France-Editions Scientifiques Medicales Elsevier, 2023) Variyenli, Halil Ibrahim; Amini, Ali; Tuncer, Azim Dogus; Khanlari, Ataollah; Kolay, Sahin
    Solar water collectors are widely utilized for providing hot water to be used in different applications. In this work, a solar water collector with a helically coiled absorber has been designed, fabricated, and examined at different test conditions to specify its overall performance. One of the major goals of using a tube-type absorber is to upgrade the thermal efficiency of the collector by providing a perpendicular angle between the absorber and incident solar rays. Also, using a helically-coiled structure make it possible to increase the absorber surface in a relatively small volume in comparison to conventional solar water collectors. In the first step of this research, the designed helically-coiled solar collector has been simulated using a solar radiation model. In the next step, the manufactured helically-coiled solar collector has been experimentally tested at three different inclination angles and various water flow rates. According to the experimental results, mean thermal efficiencies of horizontal, vertical, and angular helically-coiled collectors were obtained in the ranges of 29.48-48.23%, 27.17-47.03%, and 32.50-52.71%, respectively. In addition, sustainability index values for horizontal, vertical and angular helically-coiled collectors were achieved between the ranges of 1.0041-1.0091, 1.0039-1.0087, and 1.0043-1.0102, respectively. Moreover, the maximum deviation between numerical and experimental findings was calculated as 14%.
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    Experimental and transient CFD analysis of parallel-flow solar air collectors with paraffin-filled recyclable aluminum cans as latent heat energy storage unit
    (Elsevier, 2023) Tuncer, Azim Dogus; Amini, Ali; Khanlari, Ataollah
    In the present study, it is aimed to improve the overall performance of a parallel-flow solar air collector (PSC) using phase change material (PCM)-based latent heat energy storage unit and recyclable materials. In the simulation part of this work, two PSCs including a collector without modification and a collector equipped with PCM filled aluminum cans have been analyzed. The simulation part of the current work is handling the flow of air through the collectors and melting-solidification of PCM material inside the aluminum cans. Considering the simulation study results, three different PSC configurations have been manufactured including an unmodified PSC, a PSC with PCM-filled aluminum cans on the front side of the absorber and a PSC with PCM-filled aluminum cans on both sides (back and front) of the absorber surface. According to the results of the analyses, utilizing PCM-filled aluminum cans in both surfaces of the absorber plate of the PSC improved numerically and experimentally obtained exergetic efficiency values as 61.70% and 74.03%, respectively. Moreover, enviro-economic analysis has been conducted within the scope of this work. The payback periods of the analyzed systems were between 2.17 and 2.43 years. Employing PCM in the both sides of the absorber surface decreased the payback time of the system as 10.69% in comparison to the conventional PSC. Moreover, using PCMs on the single and double side of the absorber plate improved the annual carbon dioxide savings as 22.68% and 35.42%, respectively.
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    Experimental investigation of effect of refrigerant gases, compressor lubricant and operating conditions on performance of a heat pump
    (Journal Of Central South Univ, 2021) Afshari, Faraz; Sozen, Adnan; Khanlari, Ataollah; Tuncer, Azim Dogus; Ali, Hafiz Muhammad
    In the field of heat pumps, there are a number of parameters that affect the performance and efficiency of the apparatus, which have been the subject of studies by individual researchers in the literature. This study describes an experimental method in order to investigate the effects of some significant parameters on heat pump performance. In this regard, a laboratory heat pump setup has been utilized to operate in different working conditions for achieving an appropriate estimation to find out effects of mentioned parameters such as refrigerant type and charge amount, compressor oil viscosity, compressor cooling fan, secondary fluids temperature and flow rate. Different refrigerants have been selected and used as circulating fluid in the installed heat pump. Although this work has been devoted to a detailed attempt to recognize the effects of various parameters on the coefficient of performance (COP) value, an appropriate method has been carried out to survey the obtained results by using economic analysis. It was revealed that one of the main parameters is refrigerant charge amount which has a notable effect on COP. The temperature of the heat source was also tested and the performance of the system increased by more than 11% by employing mentioned modifications and various operating conditions. In addition, by selecting a low viscosity compressor oil, the system performance increased by 18%. This improvement is more than 6% for the case that cooling fan is installed to cool the compressor element.
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    Heat transfer enhancement of finned shell and tube heat exchanger using Fe2O3/water nanofluid
    (Journal Of Central South Univ, 2021) Afshari, Faraz; Sozen, Adnan; Khanlari, Ataollah; Tuncer, Azim Dogus
    Heat transfer mechanisms and their thermal performances need to be comprehensively studied in order to optimize efficiency and minimize energy losses. Different nanoparticles in the base fluid are investigated to upgrade the thermal performance of heat exchangers. In this numerical study, a finned shell and tube heat exchanger has been designed and different volume concentrations of nanofluid were tested to determine the effect of utilizing nanofluid on heat transfer. Fe2O3/water nanofluids with volume concentration of 1%, 1.5% and 2% were utilized as heat transfer fluid in the heat exchanger and the obtained results were compared with pure water. ANSYS Fluent software as a CFD method was employed in order to simulate the mentioned problem. Numerical simulation results indicated the successful utilization of nanofluid in the heat exchanger. Also, increasing the ratio of Fe2O3 nanoparticles caused more increment in thermal energy without important pressure drop. Moreover, it was revealed that the highest heat transfer rate enhancement of 19.1% can be obtained by using nanofluid Fe2O3/water with volume fraction of 2%.
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    Improving environmental sustainability of food waste using a solar dryer: Analyzing drying kinetics and biogas production potential
    (Pergamon-Elsevier Science Ltd, 2024) Moussaoui, Haytem; Chatir, Khaoula; Tuncer, Azim Dogus; Khanlari, Ataollah; Kouhila, Mounir; Idlimam, Ali; Lamharrar, Abdelkader
    The present work analyzes the drying kinetics of food waste, focusing on the effects of temperature, airflow and drying on biogas production. The work involves the experimental determination of food waste drying kinetics under controlled environmental conditions, including modeling the curves using a mathematical model. Indirect solar drying experiments of food waste have been performed at different air flow rates (300 m(3).h(-1) and 150 m(3).h(-1)) and temperature values (40, 50, 60, and 70 degree celsius). The temperature in the drying room was adjusted to the desired level using an auxiliary electric heating system. Energetic and environmental performance metrics of different air flow rate and temperature configurations have also been investigated and presented within the scope of this work. Additionally, an experimental investigation to measure the biogas generated by the fermentation of dried food waste was conducted. It was established that a logarithmic model best captures the drying kinetics, and the temperature and airflow are crucial variables. Increasing the drying temperature from 40 degree celsius to 70 degree celsius for the tests that performed in lower and higher flow rates improved the specific moisture extraction rate as 45.02 % and 130.65 %, respectively. It can also be observed that only phase 2 is present in the drying curve, phases 0 and 1 are absent. Furthermore, drying decreases the generation of biogas, which is primarily composed of methane, a potent greenhouse gas, according to experimental studies.
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    Improving the performance of a heat pipe evacuated solar water collector using a magnetic NiFe2O4/water nanofluid
    (Elsevier, 2023) Tuncer, Azim Dogus; Aytac, Ipek; Variyenli, Halil Ibrahim; Khanlari, Ataollah; Mantici, Sedat; Kararti, Alim
    In the recent years, heat pipe evacuated tube solar collectors (HP-ETSCs) are widely utilized due to their easy maintenance and high efficiency. However, increasing the performance of available systems is an important issue that investigated in many studies. The main goal of this study is improving the thermal performance of a HPETSC by replacing the working fluid of the system with magnetic nanofluid. In this context, magnetic type NiFe2O4/water nanofluid has been utilized as working fluid in a HP-ETSC to improve the overall performance of the system. Accordingly, NiFe2O4 nanoparticles has been mixed with distilled water at the ratio of 2 wt% in order to obtain magnetic nanofluid. The performance tests have been performed at various water flow rates (0.016 kg/ s, 0.033 kg/s, and 0.050 kg/s) using distilled water and NiFe2O4/water magnetic nanofluid. The general outcomes of this work indicated positive results of using NiFe2O4/water magnetic nanofluid on the efficiency of the HP-ETSC. Utilizing NiFe2O4/water nanofluid in the HP-ETSC as working fluid averagely increased the thermal performance as 37.72%, 39.59% and 44.96% at flow rates of 0.016 kg/s, 0.033 kg/s and 0.050 kg/s, respectively. In addition, using NiFe2O4/water magnetic nanofluid in the HP-ETSC averagely increased the exergy efficiency as 60.59%, 55.61%, 59.61% at flow rates of 0.016, 0.033 and 0.050 kg/s, respectively.
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    Improving the performance of a PCM integrated solar air collector by adding porous fins over the bottom side of the absorber: A transient CFD study
    (Elsevier, 2024) Khanlari, Ataollah; Aytac, Ipek; Tuncer, Azim Dogus; Variyenli, Halil brahim; Sahin, Havva Nur
    In this study, it is aimed to improve the utilization time period of a solar air collector by integrating a PCM unit. In this context, a PCM unit was integrated to a single -pass solar air collector. Additionally, porous fins were added into the PCM unit in order to shorten PCM melting time. Thus, six different solar collectors were designed and numerically analyzed by adding a storage unit and fins to the collector. A collector without storage and five PCM added collectors with different number of porous fins were studied. In other words, the effect of integrating PCM container and adding porous fins inside the PCM container on various parameters such as utilization time period of the collector, outlet temperature, thermal efficiency and exergy efficiency were investigated. The ANSYS Fluent program was used in numerical analyses. As a result, integrating the PCM unit to the analyzed air collector caused to extend utilization time period of the collector. Adding porous fins into the PCM unit has resulted in a significant increase in the overall performance of the system. In addition, increasing the number of porous fins accelerated the melting process of paraffin. Increasing the number of porous fins was significantly improved average energy efficiency. Average thermal efficiency of the tested collectors was obtained between 38.66 and 41.73 %. In general, as a result of numerical analysis of six different systems, the utilization time was increased by adding the PCM unit to the solar air collector. Moreover, placing porous fins inside the PCM unit increased the performance of the system by accelerating the melting of the paraffin.
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    Improving the performance of a triple-flow solar air collector using recyclable aluminum cans as extended heat transfer surfaces: An energetic, exergetic, economic and environmental survey
    (Pergamon-Elsevier Science Ltd, 2023) Tuncer, Azim Dogus; Khanlari, Ataollah
    In the current work, the effect of integrating recyclable aluminum cans as tubular fins to a triple-flow solar air collector (TFSAC) has been numerically and experimentally investigated. In this regard, conventional (TFSAC) and aluminum can-integrated (TFSAC/F) systems have been simulated by applying computational fluid dynamics approach. Moreover, developed TFSACs have been fabricated and experimentally analyzed at fixed flow rate of 0.01 kg/s. According to the experimentally obtained results, utilizing recyclable aluminum cans as fins improved the average temperature difference as 14.02%. Additionally, average exergetic efficiencies for TFSAC and TFSAC/F were calculated as 18.87% and 23.25%, respectively. Economic and environmental analyses have also been performed for the developed TFSACs within the scope of the present survey. The simple payback periods for TFSAC and TFSAC/F were gained as 1.178 and 1.035 years, respectively. Moreover, the yearly CO2 savings for TFSAC and TFSAC/F analyzed in this work were attained as 0.149 and 0.169, respectively. It should be stated that mean deviation between numerically and experimentally acquired exit air temperature values are 3.71% and 7.62%, respectively for TFSAC and TFSAC/F.
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    Improving the Performance of Unglazed Solar Air Heating Walls Using Mesh Packing and Nano-Enhanced Absorber Coating: An Energy-Exergy and Enviro-Economic Assessment
    (Mdpi, 2023) Sirin, Ceylin; Tuncer, Azim Dogus; Khanlari, Ataollah
    This study aims to upgrade the effectiveness of unglazed solar air heating walls (SWs) using mesh packing and nano-enhanced black paint. In this regard, two SW cases with 10 cm and 15 cm plenum thicknesses have been fabricated and tested simultaneously with different modifications. In other words, six different SW configurations have been designed and empirically investigated in this research. Unmodified SWs with two plenum thicknesses have been tested in the first experiment. Iron meshes have been utilized in both SWs in the second test. In the third experiment, the impact of the combined usage of mesh packing and Fe (iron) nanoparticle-enhanced black paint (absorber coating) at 2% w/w concentration on the performance has been evaluated. Experimental results exhibited that the combined usage of mesh packing and nano-doped paint in the SWs with 10 cm and 15 cm plenum thicknesses improved the average effective efficiency value by 29.54% and 31.20%, respectively, compared to the unmodified cases. Also, the average exergy efficiencies of the six tested SW configurations were attained in the range of 6.24-12.29%. Moreover, the findings of this study showed that reducing the plenum thickness and applying the combination of meshes and nano-coating improved the annual carbon dioxide savings by 44.72%.