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Drying foods and medicinal plants is a process with high energy consumption because high amount of energy is needed for evaporating the water from the surface of the fresh materials. Therefore, developing cost-effective and simple-structured drying systems with low energy demand is a crucial matter. In the present study, compact type solar dryers have been designed, manufactured and tested experimentally. Within this context, thermal and flow behavior of compact dryers with and without baffles have been analyzed using CFD method. Then, fabricated compact dryers have been experimented at different conditions to determine their performance. Experimental and numerical findings of this study illustrated the effective design of the developed compact solar dryers. However, compact solar dryer with baffles exhibited better performance than the solar dryer without baffles. According to the experimental results, mean specific moisture extraction rate in compact dryers with and without baffles obtained between the ranges of 0.55–0.69 and 0.47–0.62 kg/kWh, respectively. In addition, average exergy efficiency of drying chambers was attained over the range of 44.91–55.28%. Overall findings of this study indicated successfulness of a compact solar dryer which developed using simple and lightweight materials.
Faraz Afshari; Azim Doğuş Tuncer; Adnan Sözen; Erdem Çiftçi; Ataollah Khanlari. Experimental and numerical analysis of a compact indirect solar dehumidification system. Solar Energy 2021, 226, 72 -84.
AMA StyleFaraz Afshari, Azim Doğuş Tuncer, Adnan Sözen, Erdem Çiftçi, Ataollah Khanlari. Experimental and numerical analysis of a compact indirect solar dehumidification system. Solar Energy. 2021; 226 ():72-84.
Chicago/Turabian StyleFaraz Afshari; Azim Doğuş Tuncer; Adnan Sözen; Erdem Çiftçi; Ataollah Khanlari. 2021. "Experimental and numerical analysis of a compact indirect solar dehumidification system." Solar Energy 226, no. : 72-84.
Solar energy as a clean energy source is widely investigated to find out the effective mechanisms to meet a large part of energy demand in the near future. In the present research, a square-spiral finned quadruple-flow solar collector assisted dryer has been designed, and numerically compared with finless collector. Main aim of the current work is to develop and analyze a sustainable solar drying system. In this study, different from similar works, heat transfer surface area has been enhanced by using square-spiral geometry which is an unconventional fin type. According to the numerical findings, a finned quadruple-flow collector which found more efficient has been manufactured, integrated with a drying chamber and performance experiments have been conducted. In the manufactured solar dryer, a PV panel has been used to run utilized fan. CFD simulation and empirical outcomes of this research exhibited the successful design of finned quadruple-flow collector. Experimentally obtained average efficiency of quadruple-flow collector varied in the range of 73.27–78.19%. Also, mean exergy efficiency of drying chamber was found between 44.16 and 58.38%. Sustainability index and waste exergy ratio values as important factors were attained between the ranges of 1.93–2.73 and 0.52–0.56, respectively.
Ataollah Khanlari; Adnan Sözen; Faraz Afshari; Azim Doğuş Tuncer. Energy-exergy and sustainability analysis of a PV-driven quadruple-flow solar drying system. Renewable Energy 2021, 175, 1151 -1166.
AMA StyleAtaollah Khanlari, Adnan Sözen, Faraz Afshari, Azim Doğuş Tuncer. Energy-exergy and sustainability analysis of a PV-driven quadruple-flow solar drying system. Renewable Energy. 2021; 175 ():1151-1166.
Chicago/Turabian StyleAtaollah Khanlari; Adnan Sözen; Faraz Afshari; Azim Doğuş Tuncer. 2021. "Energy-exergy and sustainability analysis of a PV-driven quadruple-flow solar drying system." Renewable Energy 175, no. : 1151-1166.
Shell and helically coiled tube heat exchangers are comprised of curved tubes inside a shell and they are usually utilized in different sectors such as refrigeration systems, chemical processes, food industry, heat recovery systems and thermal storage systems. Improving the efficiency of heat exchangers could result in improve in the total performance of energy systems. The main purpose of the present research is to specify the effect of adding fins over helically coiled tube on thermal performance of a horizontal shell and helically coiled tube heat exchanger. In the first step of this study, CFD method was utilized to simulate finned and finless heat exchangers and determining the influence of adding fins. In the next step, manufactured finless and finned heat exchangers were tested experimentally. CFD simulation and empirical results of the present work exhibited the positive effect of integrating fins on the coil. Integrating fins over the helically coiled tube led to increase in turbulence intensity and consequently improved the heat transfer. The effectiveness of finned and finless heat exchangers was attained between 0.59 and 0.93. Integrating fins led to obtain an average improvement of 10% in the heat transfer coefficient. Furthermore, adding fins led to achieve a mean improvement of 10.6% in the overall heat transfer coefficient. While, the highest improvement in the overall heat transfer coefficient obtained as 15%.
Azim Doğuş Tuncer; Adnan Sözen; Ataollah Khanlari; Emine Yağız Gürbüz; Halil Ibrahim Variyenli. Upgrading the performance of a new shell and helically coiled heat exchanger by using longitudinal fins. Applied Thermal Engineering 2021, 191, 116876 .
AMA StyleAzim Doğuş Tuncer, Adnan Sözen, Ataollah Khanlari, Emine Yağız Gürbüz, Halil Ibrahim Variyenli. Upgrading the performance of a new shell and helically coiled heat exchanger by using longitudinal fins. Applied Thermal Engineering. 2021; 191 ():116876.
Chicago/Turabian StyleAzim Doğuş Tuncer; Adnan Sözen; Ataollah Khanlari; Emine Yağız Gürbüz; Halil Ibrahim Variyenli. 2021. "Upgrading the performance of a new shell and helically coiled heat exchanger by using longitudinal fins." Applied Thermal Engineering 191, no. : 116876.
In recent years, increasing energy demand and limited fossil fuel resources increased utilization of renewable and sustainable energy sources. Solar thermal systems are utilized for generating clean and environmentally friendly electricity and thermal energy. In this study, a single pass heater with tube-type absorber has been manufactured and integrated with a drying chamber. In this context, numerical simulations have been applied to verify the effect of absorber plate’s shape and its placement. Then, tubular solar heaters have been fabricated considering numerical simulation results. Moreover, aluminum wool has been added into the tubes with the aim of raising the thermal efficiency of the system. Drying experiments have been performed in two different air flow rates containing 0.010 and 0.013 kg/s. The numerical simulation results of this study exhibited the successfulness of tubular absorber for solar heater. Also, the experimental results showed that using aluminum wool inside the tubes led to improve in the thermal performance and 30% reduction in drying time. Average SEC values at higher and lower mas flow rates for modified dryer were found as 1.39 and 1.82 kWh/kg respectively. Also, these values were obtained for unmodified dryer as 1.94 and 2.25 kWh/kg, respectively.
Adnan Sözen; Fikret Şinasi Kazancıoğlu; Azim Doğuş Tuncer; Ataollah Khanlari; Yaşar Can Bilge; Afsin Gungor. Thermal performance improvement of an indirect solar dryer with tube-type absorber packed with aluminum wool. Solar Energy 2021, 217, 328 -341.
AMA StyleAdnan Sözen, Fikret Şinasi Kazancıoğlu, Azim Doğuş Tuncer, Ataollah Khanlari, Yaşar Can Bilge, Afsin Gungor. Thermal performance improvement of an indirect solar dryer with tube-type absorber packed with aluminum wool. Solar Energy. 2021; 217 ():328-341.
Chicago/Turabian StyleAdnan Sözen; Fikret Şinasi Kazancıoğlu; Azim Doğuş Tuncer; Ataollah Khanlari; Yaşar Can Bilge; Afsin Gungor. 2021. "Thermal performance improvement of an indirect solar dryer with tube-type absorber packed with aluminum wool." Solar Energy 217, no. : 328-341.
Shell and helically coiled tube heat exchangers composed from curved tubes inside a shell which are often preferred devices particularly in several applications like refrigeration, heat recovery systems, chemical processing, heat storage and food processing. Enhancing the effectiveness of heat exchangers can leads to increase in the overall efficiency of energy conversion systems. In addition, finding a simple and cost-effective method for enhancing the effectiveness of heat exchangers is a significant issue that should be taken into consideration. In this work, it is proposed to enhance the performance of a shell and helically coiled heat exchanger by utilizing a new modification. Within this context, a hollow tube integrated into the shell side and cold fluid enters the heat exchanger along this tube. The main purpose of this modification is regulating the fluid flow over the helically coiled tube and consequently obtaining more thermal energy. In this regard, the performance of a modified shell and helically coiled heat exchanger has been compared with a conventional vertical shell and helically coiled heat exchanger by using numerical simulation. The main objective of the simulation part of this study is determining suitable configuration for shell and helically coiled tube heat exchanger to obtain high thermal performance. Then, modified shell and helically coiled heat exchanger has been fabricated by considering simulation results. Finally, the performance analysis of developed heat exchanger has been experimentally conducted under different conditions to determine its behavior. The findings of this work showed the successful design of the modified heat exchanger. Generally, it can be said that integrating a hollow tube into the shell side of the heat exchanger led to regulate the fluid flow in the shell side that improved heat transfer. Overall heat transfer coefficient obtained in the range of 1600–3150 W/m2 K. Also, heat transfer coefficient of coil side in this study was obtained in the range of 5700–13,400 W/m2 K. Moreover, average difference between simulation and experimental results is 8%.
Azim Doğuş Tuncer; Adnan Sözen; Ataollah Khanlari; Emine Yağız Gürbüz; Halil Ibrahim Variyenli. Analysis of thermal performance of an improved shell and helically coiled heat exchanger. Applied Thermal Engineering 2020, 184, 116272 .
AMA StyleAzim Doğuş Tuncer, Adnan Sözen, Ataollah Khanlari, Emine Yağız Gürbüz, Halil Ibrahim Variyenli. Analysis of thermal performance of an improved shell and helically coiled heat exchanger. Applied Thermal Engineering. 2020; 184 ():116272.
Chicago/Turabian StyleAzim Doğuş Tuncer; Adnan Sözen; Ataollah Khanlari; Emine Yağız Gürbüz; Halil Ibrahim Variyenli. 2020. "Analysis of thermal performance of an improved shell and helically coiled heat exchanger." Applied Thermal Engineering 184, no. : 116272.
Different methods have been utilized to enhance the thermal efficiency of the heat exchangers (HEs). A widely used method to upgrade the thermal efficiency of HEs is upgrading the thermal properties of working fluid by utilizing nanoparticles. In this study, Al2O3 and CuO have been utilized to prepare Al2O3–CuO/water hybrid nanofluid. Accordingly, Al2O3 and CuO nanoparticles have been mixed into the water with 1% (50:50) weight concentration. The main objective of this work is testing the prepared hybrid nanofluid in plate-type HEs (PHEs) with 8, 12 and 16 plates to determine the influence of number of plates on heat transfer improvement by hybrid nanofluid. Experimental findings of the present study demonstrated that utilizing Al2O3–CuO/water hybrid-type nanofluid in the PHE enhanced thermal efficiency notably in comparison with single-type nanofluids. Using this hybrid nanofluid increased the thermal performance in all PHEs with different number of plates. However, it is observed that increasing number of plates led to more increment in thermal performance by utilizing hybrid nanofluid. The highest increment in overall heat transfer coefficient was obtained as 12%, 19% and 20% in PHEs with eight, 12 and 16 plates, respectively. In addition, the highest enhancement in effectiveness was achieved as 10%, 11.7% and 16% in PHEs with eight, 12 and 16 plates, respectively.
Emine Yağız Gürbüz; Adnan Sözen; Halil Ibrahim Variyenli; Ataollah Khanlari; Azim Doğuş Tuncer. A comparative study on utilizing hybrid-type nanofluid in plate heat exchangers with different number of plates. Journal of the Brazilian Society of Mechanical Sciences and Engineering 2020, 42, 1 -13.
AMA StyleEmine Yağız Gürbüz, Adnan Sözen, Halil Ibrahim Variyenli, Ataollah Khanlari, Azim Doğuş Tuncer. A comparative study on utilizing hybrid-type nanofluid in plate heat exchangers with different number of plates. Journal of the Brazilian Society of Mechanical Sciences and Engineering. 2020; 42 (10):1-13.
Chicago/Turabian StyleEmine Yağız Gürbüz; Adnan Sözen; Halil Ibrahim Variyenli; Ataollah Khanlari; Azim Doğuş Tuncer. 2020. "A comparative study on utilizing hybrid-type nanofluid in plate heat exchangers with different number of plates." Journal of the Brazilian Society of Mechanical Sciences and Engineering 42, no. 10: 1-13.
Disposal of sewage sludge is an important problem for the sustainability of cities. In recycling process of sewage sludge, a big part of energy demand is consumed in the drying process. Therefore, utilizing clean and sustainable energies in recycling process of sewage sludge can be a good solution. In this work, a drying chamber with transparent cover has been designed and analyzed in the process of drying sewage sludge experimentally and numerically. Also, a conventional drying chamber has been tested and its performance compared with modified drying chamber’s performance. The main purpose of modifying the drying chamber using transparent cover is to harvest more solar energy in the system and consequently reduction in the drying time. Moreover, in the drying tests a single-pass conventional unglazed solar air collector has been combined with the drying chamber. The performance tests of drying systems have been conducted in two various flow rates including 0.010 and 0.014 kg/s. Experimental and numerical findings demonstrated that using drying chamber with transparent cover reduced the drying time significantly. The obtained average specific energy consumption and specific moisture extraction rate values are in the range of 1.77–2.86 kWh/kg and 0.77–1.34 kg/kWh, respectively. Moreover, levelized cost of heating values were found between 1.7 and 2.0 $-ct/kWh for the system which uses drying chamber with transparent cover.
Ataollah Khanlari; Azim Doğuş Tuncer; Adnan Sözen; Ceylin Şirin; Afsin Gungor. Energetic, environmental and economic analysis of drying municipal sewage sludge with a modified sustainable solar drying system. Solar Energy 2020, 208, 787 -799.
AMA StyleAtaollah Khanlari, Azim Doğuş Tuncer, Adnan Sözen, Ceylin Şirin, Afsin Gungor. Energetic, environmental and economic analysis of drying municipal sewage sludge with a modified sustainable solar drying system. Solar Energy. 2020; 208 ():787-799.
Chicago/Turabian StyleAtaollah Khanlari; Azim Doğuş Tuncer; Adnan Sözen; Ceylin Şirin; Afsin Gungor. 2020. "Energetic, environmental and economic analysis of drying municipal sewage sludge with a modified sustainable solar drying system." Solar Energy 208, no. : 787-799.
Clean and sustainable energy generation is a substantial necessity for developing world. Solar energy is an extensively utilized renewable energy resource and it can be utilized for both electricity and thermal energy generation. Solar thermal applications could be utilized in various processes like space heating and drying. In this study, two cost-effective and simple-structured solar air heaters were designed and manufactured. The first heater is a hollow tube-type heater. Second heater has the same basic properties but iron meshes were added in the flow channel to extend its heat transfer surface area. The mesh modified tube-type heater was manufactured regarding to numerical simulation findings using Ansys Fluent software. Both heaters were integrated with a drying chamber and drying tests were conducted at three air mass flow rates (0.014, 0.011 and 0.009 kg/s). The maximum instantaneous thermal efficiency in iron mesh modified solar heater was obtained as 74.71%. Utilizing mesh modification enhanced thermal efficiency of the tube-type heater up to 11%. Also, the highest values of the average energy efficiency of the drying system was achieved as 50.85% as well in iron mesh modified solar assisted dryer. It is observed that this tubular SAH design is promising in view of renewable hot air generation with its simple and cost-effective structure since it includes no casing, no insulation material and fabricated from sheet metal.
Adnan Sözen; Ceylin Şirin; Ataollah Khanlari; Azim Doğuş Tuncer; Emine Yağız Gürbüz. Thermal performance enhancement of tube-type alternative indirect solar dryer with iron mesh modification. Solar Energy 2020, 207, 1269 -1281.
AMA StyleAdnan Sözen, Ceylin Şirin, Ataollah Khanlari, Azim Doğuş Tuncer, Emine Yağız Gürbüz. Thermal performance enhancement of tube-type alternative indirect solar dryer with iron mesh modification. Solar Energy. 2020; 207 ():1269-1281.
Chicago/Turabian StyleAdnan Sözen; Ceylin Şirin; Ataollah Khanlari; Azim Doğuş Tuncer; Emine Yağız Gürbüz. 2020. "Thermal performance enhancement of tube-type alternative indirect solar dryer with iron mesh modification." Solar Energy 207, no. : 1269-1281.
Each day high portion of municipal wastewater sludge is generated in cities and developing a suitable and environmentally friendly treatment technique for municipal wastewater is required. Providing a cost-effective and suitable way for sewage sludge refinement with the purpose of reducing environmental impacts or reutilization of sewage sludge can be an important issue for researchers. In the present study, a novel convex-type solar absorber assisted dryer has been designed for drying municipal sewage sludge. In the experimental setup, an unglazed single-pass solar air collector has been used as main air heater and integrated to the drying conventional and modified drying chambers. Experimental and CFD simulation have been used to investigate the performance of fabricated solar energy assisted dryers. Also, the effectiveness of the developed system has been analyzed in various conditions to clarify the potential of fabricated dryers. According to the results utilizing convex solar absorber led to provide high air flow rate with high temperature inside the drying chamber and consequently shortened the drying time. Experimentally obtained average energy efficiency of the modified and conventional indirect solar drying system were in the range of 32.85-47.09% and 21.32-30.45%, respectively. Moreover, the experimental results collected from CSD and CSASD are also discussed in terms of R2, RMSE, RRMSE, MBE, and MAPE, and a very satisfying correlation between the systems CSD and CSASD is noticed with the statistical metrics. The findings of the present study demonstrate the potential of utilizing the designed dryers in drying municipal wastewater sludge.
Azim Doğuş Tuncer; Adnan Sözen; Faraz Afshari; Ataollah Khanlari; Ceylin Şirin; Afsin Gungor. Testing of a novel convex-type solar absorber drying chamber in dehumidification process of municipal sewage sludge. Journal of Cleaner Production 2020, 272, 122862 .
AMA StyleAzim Doğuş Tuncer, Adnan Sözen, Faraz Afshari, Ataollah Khanlari, Ceylin Şirin, Afsin Gungor. Testing of a novel convex-type solar absorber drying chamber in dehumidification process of municipal sewage sludge. Journal of Cleaner Production. 2020; 272 ():122862.
Chicago/Turabian StyleAzim Doğuş Tuncer; Adnan Sözen; Faraz Afshari; Ataollah Khanlari; Ceylin Şirin; Afsin Gungor. 2020. "Testing of a novel convex-type solar absorber drying chamber in dehumidification process of municipal sewage sludge." Journal of Cleaner Production 272, no. : 122862.
Over the past years, there has been a huge growth in the solar energy research, development and progress, due to being a renewable, economical and non-polluting energy source. In this research, different design and placement of turbulators inside a cost-effective tube-type solar air heater (TSAH) has been analyzed to upgrade thermal performance. Both experimental and CFD analysis have been performed in order to survey the performance of solar heating systems. Numerical method has been done by utilizing Fluent program in order to simulate real models and also verified with experimental results. It is proposed to improve the thermal efficiency of TSAH by integrating turbulators in different modifications. According to the experimental outcomes maximum instantaneous heater efficiency was reached to 72.41%. Also, experimental and numerical average temperature difference values in TSAHs varied in the range of 9.16–14.54 °C and 9.50–14.95 °C, respectively. The experimental and numerical simulation results exhibited successful design of this simple and inexpensive alternative hot air generation system. Manufactured simple-structured TSAHs in the present work have acceptable thermal performance in comparison to more complex solar heaters in the literature. This type of solar heater could be used in different applications such as; drying, greenhouse heating, space heating and air preheating.
Faraz Afshari; Adnan Sözen; Ataollah Khanlari; Azim Doğuş Tuncer; Ceylin Şirin. Effect of turbulator modifications on the thermal performance of cost-effective alternative solar air heater. Renewable Energy 2020, 158, 297 -310.
AMA StyleFaraz Afshari, Adnan Sözen, Ataollah Khanlari, Azim Doğuş Tuncer, Ceylin Şirin. Effect of turbulator modifications on the thermal performance of cost-effective alternative solar air heater. Renewable Energy. 2020; 158 ():297-310.
Chicago/Turabian StyleFaraz Afshari; Adnan Sözen; Ataollah Khanlari; Azim Doğuş Tuncer; Ceylin Şirin. 2020. "Effect of turbulator modifications on the thermal performance of cost-effective alternative solar air heater." Renewable Energy 158, no. : 297-310.
Halil Ibrahim Variyenli; Ataollah Khanlari. Analyzing the Environmental Effects of Conventional and Condensing Combi Boilers Using Natural Gas. Journal of Polytechnic 2020, 1 .
AMA StyleHalil Ibrahim Variyenli, Ataollah Khanlari. Analyzing the Environmental Effects of Conventional and Condensing Combi Boilers Using Natural Gas. Journal of Polytechnic. 2020; ():1.
Chicago/Turabian StyleHalil Ibrahim Variyenli; Ataollah Khanlari. 2020. "Analyzing the Environmental Effects of Conventional and Condensing Combi Boilers Using Natural Gas." Journal of Polytechnic , no. : 1.
Everyday a large amount of sewage sludge is produced in cities and proper and environmentally friendly municipal wastewater treatment is needed. Finding a convenient and affordable way for sewage sludge refinement to reduce environmental pollution or even utilization of sewage sludge will be a very attractive challenge for scientists. In the recent years, sustainable and renewable energy sources like solar energy are extensively utilized in different fields including heating, electricity generation, and drying applications. In this study, V-groove triple-pass (V-TPSAH) and V-groove quadruple-pass (V-QPSAH) solar air heaters have been designed, manufactured and tested for drying municipal sewage sludge. Also, two different types of drying chambers (DC-I: conventional, DC-II: solar absorber) have been integrated with each solar heater. Experimental and numerical methods have been applied to analyze the efficiency of developed solar air heater assisted drying systems. The system's performance has been tested in different working conditions to clarify the utilization potential of manufactured system. According to the experimental results solar air heater's average efficiency are in the range of 70.12–81.70%. In addition, obtained experimental findings are in line with numerical results. The outcomes of this study present the potential of using the developed systems in drying municipal sewage sludge to be used in multi purposes.
Ataollah Khanlari; Adnan Sözen; Faraz Afshari; Ceylin Şirin; Azim Doğuş Tuncer; Afsin Gungor. Drying municipal sewage sludge with v-groove triple-pass and quadruple-pass solar air heaters along with testing of a solar absorber drying chamber. Science of The Total Environment 2019, 709, 136198 .
AMA StyleAtaollah Khanlari, Adnan Sözen, Faraz Afshari, Ceylin Şirin, Azim Doğuş Tuncer, Afsin Gungor. Drying municipal sewage sludge with v-groove triple-pass and quadruple-pass solar air heaters along with testing of a solar absorber drying chamber. Science of The Total Environment. 2019; 709 ():136198.
Chicago/Turabian StyleAtaollah Khanlari; Adnan Sözen; Faraz Afshari; Ceylin Şirin; Azim Doğuş Tuncer; Afsin Gungor. 2019. "Drying municipal sewage sludge with v-groove triple-pass and quadruple-pass solar air heaters along with testing of a solar absorber drying chamber." Science of The Total Environment 709, no. : 136198.
Different strategies have been proposed to improve the efficiency of the energy conversion systems. One of the outstanding technics for heat transfer increment is utilizing nanofluid as working fluid. This experimental study investigates the effect of using kaolin/deionized water nanofluid that is comprise various kinds of metal oxides in different ratios, on thermal behavior of counter flow concentric tube (CFCT) heat exchanger and parallel flow concentric tube (PFCT) heat exchanger. The prepared kaolin/deionized water nanofluid solution has 2% (wt/wt) nanoparticle concentration. Also, to prevent flocculation and to enhance stability of the prepared nanofluid, sodium dodecyl benzene sulfonate surface-active agent has been mixed into the solution. The experiments have been conducted in various conditions to investigate the influence of using nanofluid. Utilizing kaolin/deionized water nanofluid as working fluid caused maximum improvement of 37% and 12% in overall heat transfer coefficient in CFCT and PFCT heat exchangers respectively, in comparison with deionized water.
Ataollah Khanlari; Duygu Yılmaz Aydın; Adnan Sözen; Metin Gürü; Halil Ibrahim Variyenli. Investigation of the influences of kaolin-deionized water nanofluid on the thermal behavior of concentric type heat exchanger. Heat and Mass Transfer 2019, 56, 1453 -1462.
AMA StyleAtaollah Khanlari, Duygu Yılmaz Aydın, Adnan Sözen, Metin Gürü, Halil Ibrahim Variyenli. Investigation of the influences of kaolin-deionized water nanofluid on the thermal behavior of concentric type heat exchanger. Heat and Mass Transfer. 2019; 56 (5):1453-1462.
Chicago/Turabian StyleAtaollah Khanlari; Duygu Yılmaz Aydın; Adnan Sözen; Metin Gürü; Halil Ibrahim Variyenli. 2019. "Investigation of the influences of kaolin-deionized water nanofluid on the thermal behavior of concentric type heat exchanger." Heat and Mass Transfer 56, no. 5: 1453-1462.
Purpose The plate heat exchangers (PHE) with small size but large efficiency are compact types of heat exchangers formed by corrugated thin pressed plates, operating at higher pressures when compared to most other traditional exchangers. This paper aims to analyze heat transfer characteristics in the PHE experimentally and numerically. Design/methodology/approach Computational fluid dynamics analysis has been used to simulate the problem by using the ANSYS fluent 16 software. Also, the effect of using TiO2/water nanofluid as working fluid was investigated. TiO2/water nanofluid had 2% (Wt/Wt) nanoparticle content. To improve solubility of the TiO2 nanoparticles, Triton X-100 was added to the mixture. The results have been achieved in different working condition with changes in fluid flow rate and its temperature. Findings The obtained results showed that using TiO2/water nanofluid improved the overall heat transfer coefficient averagely as 6%, whereas maximum improvement in overall heat transfer coefficient was 10%. Also, theoretical and experimental results are in line with each other. Originality/value The most important feature which separates the present study from the literature is that nanofluid is prepared by using TiO2 nanoparticles in optimum size and mixing ratio with surfactant usage to prevent sedimentation and flocculation problems. This process also prevents particle accumulation that may occur inside the PHE. The main aim of the present study is to predict heat transfer characteristics of nanofluids in a plate heat exchanger. Therefore, it will be possible to analyze thermal performance of the nanofluids without any experiment.
Ataollah Khanlari; Adnan Sözen; Halil Ibrahim Variyenli. Simulation and experimental analysis of heat transfer characteristics in the plate type heat exchangers using TiO2/water nanofluid. International Journal of Numerical Methods for Heat & Fluid Flow 2019, 29, 1343 -1362.
AMA StyleAtaollah Khanlari, Adnan Sözen, Halil Ibrahim Variyenli. Simulation and experimental analysis of heat transfer characteristics in the plate type heat exchangers using TiO2/water nanofluid. International Journal of Numerical Methods for Heat & Fluid Flow. 2019; 29 (4):1343-1362.
Chicago/Turabian StyleAtaollah Khanlari; Adnan Sözen; Halil Ibrahim Variyenli. 2019. "Simulation and experimental analysis of heat transfer characteristics in the plate type heat exchangers using TiO2/water nanofluid." International Journal of Numerical Methods for Heat & Fluid Flow 29, no. 4: 1343-1362.
Ataollah Khanları; Ilker Ay. A Numerical Study on Determination of the Optimal Hole Diameter and Pitch Value for the Unglazed Transpired Solar Collectors. Journal of Polytechnic 2018, 1 .
AMA StyleAtaollah Khanları, Ilker Ay. A Numerical Study on Determination of the Optimal Hole Diameter and Pitch Value for the Unglazed Transpired Solar Collectors. Journal of Polytechnic. 2018; ():1.
Chicago/Turabian StyleAtaollah Khanları; Ilker Ay. 2018. "A Numerical Study on Determination of the Optimal Hole Diameter and Pitch Value for the Unglazed Transpired Solar Collectors." Journal of Polytechnic , no. : 1.
Energy, which is needed for every aspect of life, plays a key role for the development of the countries. Countries need to use energy efficiently to be advantageous in the global competition and ensure the sustainable development. Countries using the energy efficiently succeed economically and have leading the field in the competition. The purpose of this study is to put forward to the role and importance of energy efficiency for the sustainable development of the countries. In this study, energy efficiency has been examined conceptually considering the studies in the literature and the role and importance of energy efficiency has been emphasized for the sustainable development of the countries.
Gökhan Durmuş; Onuralp Uluer; Mustafa Aktaş; Ibrahim Karaağaç; Ataollah Khanlari; Ümit Ağbulut; Damla Nur Çelik. A Study on Some Factors Affecting on CO2 Curing of Expanded Perlite Based Thermal Insulation Panel. Proceedings of EECE 2020 2018, 61 -70.
AMA StyleGökhan Durmuş, Onuralp Uluer, Mustafa Aktaş, Ibrahim Karaağaç, Ataollah Khanlari, Ümit Ağbulut, Damla Nur Çelik. A Study on Some Factors Affecting on CO2 Curing of Expanded Perlite Based Thermal Insulation Panel. Proceedings of EECE 2020. 2018; ():61-70.
Chicago/Turabian StyleGökhan Durmuş; Onuralp Uluer; Mustafa Aktaş; Ibrahim Karaağaç; Ataollah Khanlari; Ümit Ağbulut; Damla Nur Çelik. 2018. "A Study on Some Factors Affecting on CO2 Curing of Expanded Perlite Based Thermal Insulation Panel." Proceedings of EECE 2020 , no. : 61-70.
Onuralp Uluer; Ibrahim Karaağaç; Mustafa Aktaş; Gökhan Durmuş; Ümit Ağbulut; Ataollah Khanlari; Damla Nur Çelik. An investigation of usability of expanded perlite in heat insulation technologies. Pamukkale University Journal of Engineering Sciences 2018, 24, 36 -42.
AMA StyleOnuralp Uluer, Ibrahim Karaağaç, Mustafa Aktaş, Gökhan Durmuş, Ümit Ağbulut, Ataollah Khanlari, Damla Nur Çelik. An investigation of usability of expanded perlite in heat insulation technologies. Pamukkale University Journal of Engineering Sciences. 2018; 24 (1):36-42.
Chicago/Turabian StyleOnuralp Uluer; Ibrahim Karaağaç; Mustafa Aktaş; Gökhan Durmuş; Ümit Ağbulut; Ataollah Khanlari; Damla Nur Çelik. 2018. "An investigation of usability of expanded perlite in heat insulation technologies." Pamukkale University Journal of Engineering Sciences 24, no. 1: 36-42.
M. Bahadır Özdemir; Mustafa Aktaş; Seyfi Şevik; Ataollah Khanlari. Modeling of a convective-infrared kiwifruit drying process. International Journal of Hydrogen Energy 2017, 42, 18005 -18013.
AMA StyleM. Bahadır Özdemir, Mustafa Aktaş, Seyfi Şevik, Ataollah Khanlari. Modeling of a convective-infrared kiwifruit drying process. International Journal of Hydrogen Energy. 2017; 42 (28):18005-18013.
Chicago/Turabian StyleM. Bahadır Özdemir; Mustafa Aktaş; Seyfi Şevik; Ataollah Khanlari. 2017. "Modeling of a convective-infrared kiwifruit drying process." International Journal of Hydrogen Energy 42, no. 28: 18005-18013.
Drying is one of the easily accessible and the most widespread processing technologies that have been used since ancient times for preserving fruits. Drying is an energy-intensive and time-consuming process, so reducing energy demand is important. The main aim of this paper is to analyze the heat and mass transfer characteristics of product in the drying chamber and in addition to this, three-dimensional (3-D) computational fluid dynamic (CFD) simulation was performed. The analyses of heat and mass transfer were investigated theoretically and experimentally in infrared dryer (IRD). The dryer consists of air to air heat recovery unit and proportional temperature controller. Experiments were performed at 0.5 and 0.25 m/s air velocities and at 60 and 65°C apricot surface temperatures which were controlled by three thermocouples contacted on top side of the product. In order to use energy more effectively and improve the drying characteristics of apricot, analyses were performed under different drying conditions. Since the heat recovery unit has a key role in this system, the performance of this unit was investigated and recovered energy ratio was between 58 and 62%. The calculated moisture diffusivity values varied from 1.7 × 10−10 to 1.15 × 10−9 for apricot, and the highest value of average energy efficiency was obtained as 16.43% at 65°C temperature and 0.25 m/s air velocity. Theoretical and experimental results are in line with each other.
Mustafa Aktaş; Adnan Sözen; Ali Amini; Ataollah Khanlari. Experimental analysis and CFD simulation of infrared apricot dryer with heat recovery. Drying Technology 2017, 35, 766 -783.
AMA StyleMustafa Aktaş, Adnan Sözen, Ali Amini, Ataollah Khanlari. Experimental analysis and CFD simulation of infrared apricot dryer with heat recovery. Drying Technology. 2017; 35 (6):766-783.
Chicago/Turabian StyleMustafa Aktaş; Adnan Sözen; Ali Amini; Ataollah Khanlari. 2017. "Experimental analysis and CFD simulation of infrared apricot dryer with heat recovery." Drying Technology 35, no. 6: 766-783.
Mustafa Aktaş; Ataollah Khanlari; Ali Amini; Seyfi Şevik. Performance analysis of heat pump and infrared–heat pump drying of grated carrot using energy-exergy methodology. Energy Conversion and Management 2017, 132, 327 -338.
AMA StyleMustafa Aktaş, Ataollah Khanlari, Ali Amini, Seyfi Şevik. Performance analysis of heat pump and infrared–heat pump drying of grated carrot using energy-exergy methodology. Energy Conversion and Management. 2017; 132 ():327-338.
Chicago/Turabian StyleMustafa Aktaş; Ataollah Khanlari; Ali Amini; Seyfi Şevik. 2017. "Performance analysis of heat pump and infrared–heat pump drying of grated carrot using energy-exergy methodology." Energy Conversion and Management 132, no. : 327-338.