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Öğe A NOVEL THERMAL ANALYSIS FOR COOKING PROCESS IN BULGUR PRODUCTION: DESIGN CONSIDERATIONS, ENERGY EFFICIENCY AND WASTEWATER DIMINUTION FOR INDUSTRIAL PROCESSES(Turkish Soc Thermal Sciences Technology, 2020) Yilmaz, Ibrahim Halil; Soylemez, Mehmet SaitThe main contribution of this study is to present a novel thermal model for analyzing the wheat cooking process and to propose a design procedure for an energy-efficient cooking pot. A small-scale cooking pot was designed and an experimental setup was installed to verify the model under various operating conditions. The developed model was solved using the Engineering Equation Solver software. Results were compared with those of the experiments and good agreement was obtained. Additionally, a computational fluid dynamics model was developed to verify the thermal model and have a useful design tool for large-scale cooking pots. It was found that the energy efficiency of the cooking process can be enhanced by initiating nucleate boiling (at similar to 5 degrees C minimum temperature difference between the heating element surface and saturation) which will supply the minimum heat flux on the helicoidal heat exchanger of the cooking pot. Lessening the energy demand but preserving the final product quality has decreased the 5-day biological oxygen demand of wastewater at least 50%. It is proposed that the wheat to water ratio can be reduced to 1.0-1.2 once the energy optimization and water recovery practices are satisfied. The estimated average specific energy consumption rate lies between 400.475 +/- 5% W/kg (thermal power supplied for one kilogram of wheat) which can be reduced similar to 25% further by reducing the wheat to water ratio to 1.0. The results reported in the present study are expected to guide thermal and food engineers for the design applications of industrial cooking pots, energy optimization with less harmful wastewater and process control strategies for cooking of wheat.Öğe A novel thermal analysis for cooking process in bulgur production: Design considerations, energy efficiency and wastewater diminution for industrial processes(Turk Isı Bilimi ve Teknigi Dernegi, 2020) Yilmaz, Ibrahim Halil; Söylemez, Mehmet SaitThe main contribution of this study is to present a novel thermal model for analyzing the wheat cooking process and to propose a design procedure for an energy-efficient cooking pot. A small-scale cooking pot was designed and an experimental setup was installed to verify the model under various operating conditions. The developed model was solved using the Engineering Equation Solver software. Results were compared with those of the experiments and good agreement was obtained. Additionally, a computational fluid dynamics model was developed to verify the thermal model and have a useful design tool for large-scale cooking pots. It was found that the energy efficiency of the cooking process can be enhanced by initiating nucleate boiling (at ~5 °C minimum temperature difference between the heating element surface and saturation) which will supply the minimum heat flux on the helicoidal heat exchanger of the cooking pot. Lessening the energy demand but preserving the final product quality has decreased the 5-day biological oxygen demand of wastewater at least 50%. It is proposed that the wheat to water ratio can be reduced to 1.0?1.2 once the energy optimization and water recovery practices are satisfied. The estimated average specific energy consumption rate lies between 400-475 ±5% W/kg (thermal power supplied for one kilogram of wheat) which can be reduced ~25% further by reducing the wheat to water ratio to 1.0. The results reported in the present study are expected to guide thermal and food engineers for the design applications of industrial cooking pots, energy optimization with less harmful wastewater and process control strategies for cooking of wheat. © 2020 Turk Isı Bilimi ve Teknigi Dernegi. All rights reserved.Öğe A thermodynamic evaluation on high pressure condenser of double effect absorption refrigeration system(Pergamon-Elsevier Science Ltd, 2016) Yilmaz, Ibrahim Halil; Saka, Kenan; Kaynakli, OmerOne of the parameters affecting the COP of the absorption system can be considered as the thermal balance between the high pressure condenser (HPC) and the low pressure generator (LPG) since heat rejected from the HPC is utilized as an energy source by the LPG. Condensation of the water vapor in the HPC depends on the heat removal via the LPG. This circumstance is significant for making an appropriate design and a controllable system with high performance in practical applications. For this reason, a thermodynamic analysis for the HPC of a double effect series flow water/lithium bromide absorption refrigeration system was emphasized in this study. A simulation was developed to investigate the energy transfer between the HPC and LPG. The results show that the proper designation of the HPC temperature improves the COP and ECOP due its significant impact, and its value necessarily has to be higher than the outlet temperature of the LPG based on the operating scheme. Furthermore, the COP and ECOP of the absorption system can be raised in the range of 9.72-35.09% in case of 2 degrees C-temperature increment in the HPC under the described conditions to be applied. (C) 2016 Elsevier Ltd. All rights reserved.Öğe An innovative dynamic model for an integrated solar combined cycle power plant under off-design conditions(Pergamon-Elsevier Science Ltd, 2020) Abdelhafidi, Nedjma; Yilmaz, Ibrahim Halil; Bachari, Nour El IslamThe integrated solar combined cycle power plants are currently the most efficient way of converting solar energy into electricity. Increasing the thermal efficiency of these plants depends strongly on the dynamic characteristics of off-design conditions and the operational control strategies. An innovative mathematical model has been presented to investigate the dynamic behavior of an Integrated Solar Combined Cycle power plant in Hassi R'mel, Algeria under off-design conditions in this study. The proposed model is analyzed via computer simulation on the Matlab environment using the recent operating parameters of the plant and the meteorological data recorded by the Abener hybrid solar-gas central of Hassi R'mel. The simulation results indicate that the experimental data of the outlet temperature of the solar field and the power generated by the plant verify the predictions found by the model. The root mean square error and mean absolute error range respectively between 4.03 and 4.12 degrees C and 1.45-1.80 degrees C for the outlet temperature of the solar cycle and 1.61-1.72 MW and 0.67-0.75 MW for the net power under specified experimental conditions. It is revealed that the off-design conditions, particularly the direct normal irradiance and the wind speed, affect the Integrated Solar Combined Cycle performance significantly. The presented model is an effective tool that can provide a wealth of information to power plant operators and designers during operational plant design, and management to mitigate the adverse impact of possible off-design conditions on power production and to boost power production by management strategies.Öğe Design of spectrally selective multilayer stacks with optimized properties for mid-temperature concentrating solar applications(Elsevier, 2024) Ustun, Kadir; Kılıç, Fatih; Yilmaz, Ibrahim HalilThis study presents an original method to optimally design the multi-layer stacks at varying layer counts, depths, and orders using 20 widely used candidate materials on copper (Cu) and stainless steel (SS) substrates. The water cycle algorithm (WCA) for the constrained design problem using genetic operators was adapted as an optimization algorithm. The study aims to design stacks for two different substrates, with high absorptivity (>0.95) in the solar spectrum and low emissivity (<0.1) in the infrared region for concentrating solar applications operating between 673 and 973 K. Two fitness functions, F-1 and F-2, are proposed and benchmarked at specified design conditions to analyze their efficacies. Results show that the increase in the coating efficiency (eta(c)) is less than 0.94 % in the case of adding more than 5 layers on the substrates. The difference between the coating efficiencies of the proposed stacks using SS and Cu substrates is less than 0.26 %. It is believed that the advanced optimization algorithm given in the paper will pave the way for more efficient solar selective absorber designs.Öğe Enhancing the overall thermal performance of a large aperture parabolic trough solar collector using wire coil inserts(Elsevier, 2020) Yilmaz, Ibrahim Halil; Mwesigye, Aggrey; Goksu, Taha TunaWith the use of large apertures (higher concentration ratios) in parabolic trough solar collectors, increased temperature gradients, increased heat losses and increased heat transfer irreversibilities become inevitable. As such, means of reducing the magnitude of these operating parameters to enhance the overall thermal and thermodynamic performances become crucial. In this study, the use of wire coil inserts in the receiver's absorber tube to improve the parabolic trough solar collector's performance and to lessen the associated temperature gradients is presented. The parabolic trough solar collector having an aperture width of 9 m and a rim angle of 80 degrees was modeled. Using Monte-Carlo ray tracing, the realistic heat flux profile on the receiver's absorber tube was obtained. The resulting non-uniform heat flux profile was later coupled to a finite volume based computational fluid dynamics model. The working fluid properties were considered to be temperature-dependent. The wire coil inserts with a pitch of 0.076, 0.114 and 0.152 m and widths of 0.03, 0.033 and 0.036 m were examined in this study. The wire coil has a triangular cross-section of 0.0076 m in size. Results show significant improvements in receiver thermal performance with the use of wire coil inserts owing to the improved fluid mixing, disruption of the thermal boundary layer and reduction in the absorber tube temperatures. The heat transfer performance is increased up to 183% whereas the thermal efficiency improves between 0.4 and 1.4% when the flow rate is below 13 m(3)/h.Öğe Evaluation of municipal solid waste options in Turkey: Scenarios for energy recovery, carbon mitigation and consequent financial strategies(Elsevier, 2019) Yilmaz, Ibrahim Halil; Abdulvahitoglu, AsliSolid waste management is a challenging issue in Turkey not only due to population and economic growths but its adverse environmental impact, financial problems and technological obstacles, as well. The detailed evaluation of solid waste options is significant not to end up with issues such as shutting down the plants and stopping the investments which may cause serious environmental problems as a result of uncontrolled landfill gas emissions. This research presents a theoretical model for energy recovery from the municipal solid waste (MSW) in Turkey, and the consequent carbon mitigation scenarios and financial strategies regarding the adoption of European Union acquis, respectively. The model predicts the population growth compatible with the baseline scenario of Turkish Statistical Institute data and the MSW generation for each city of Turkey between 2004-2043. The three scenarios, namely open dump, landfill and incineration, are taken into consideration for greenhouse gas (GHG) emissions, energy recovery from emissions and economics subject to the Turkish environmental regulations towards the progress of this adoption. The aim of the research is to fulfill the literature gap by proposing practical formulations and realistic models for the mentioned scenarios and considering the energy, economy and ecology nexus based on the regional characteristics of solid waste systems as a consequence of adapting the Turkish MSW regulations and management. Results show that the maximum potential of electricity production is estimated to be 3461-13,450 GW h (0.40-1.56 GW/annum) in the landfill scenario while it is 1572-8386 GW h (0.17-0.96 GW/annum) in the incineration scenario. According to the nationwide projections, Turkey will have consumed the electricity of 437 TW h and 2236 TW h by 2023 and 2043, respectively. While the landfill scenario would meet 0.40-1.40% and 0.15-0.60% of the nationwide electricity production for the interested years, respectively; the incineration scenario would supply 0.06-0.34% and 0.07-0.38% of the nationwide electricity consumption. The maximum total savings for the landfill and incineration scenarios would range from 35.2-66.7 and 32.7-64.5 billion $, respectively in a time horizon at which the total amount of wastes for the corresponding scenarios are equivalent to each other. It is stressed that the landfill scenario would be better for lowering the GHG emissions in case of proper emission control.Öğe Experimental analysis and dynamic simulation of a solar-assisted industrial process using parabolic trough solar collectors under outdoor conditions(Elsevier, 2023) Yilmaz, Ibrahim Halil; Soylemez, Mehmet Sait; Yumrutas, RecepSolar heat for industrial processes has gathered much attention and technological vision over time due to energy savings and environmental concerns even though there are various restrictions and complications in integrating solar collector technologies with industry. This study aims to cut thermal energy consumption and anthropogenic gas emissions in bulgur industry by proposing a novel experimental design for a solar-assisted process heat (SAPH) system. An experimental method has been addressed for the food treatment process integrated with parabolic trough solar collectors (PTSCs) and the proposed dynamic model of the system has been simulated for predicting the annual performance. The performance parameters of the individual system components have been analyzed during the days of the experiments conducted. Operational experience gained from the application reveals that the overall system efficiency depends keenly on the collector efficiency of the PTSCs used, load characteristics, and operating conditions. Furthermore, selecting an appropriate size for all heat-exchange devices is a critical parameter to improve the overall efficiency significantly and avert long-term temperature fluctuations. The long-term simulation results reveal that the annual efficiency can be obtained as 20.8 % for the SAPH system and further improved with system optimization.Öğe Exploitable biomass status and potential of the Southeastern Anatolia Region, Turkey(Taylor & Francis Inc, 2018) Yilmaz, Ibrahim Halil; Saka, KenanIn this study, the exploitable biomass potential of nine provinces located in the Southeastern Anatolia region of Turkey was investigated. Animal- and vegetal-derived biomasses were taken into consideration in the analyses. The animal-derived biomass was handled as poultry, small ruminants, and cattle. The vegetal-derived biomass was accounted as field, garden, and vegetable crops. The contribution of each species on the biomass energy potential was studied. The available animal and vegetal residues in the region were estimated to be, respectively, equal to 6.2% and 9.4% of the corresponding residual amount in Turkey. The annual total biomass potential of the region was found to be approximately 83.4 PJ which could meet 15.7% energy demand of the region.Öğe Modeling, simulation and performance analysis of parabolic trough solar collectors: A comprehensive review(Elsevier Sci Ltd, 2018) Yilmaz, Ibrahim Halil; Mwesigye, AggreySolar thermal systems are advantageous since it is easier to store heat than electricity on a large scale. As such, concentrated solar power is receiving considerable interest among researchers, developers and governments. Several concentrated solar power technologies have been developed including the solar tower, the parabolic trough technology, solar dish and linear Fresnel systems. Among them, the parabolic trough solar collector is a proven technology used dominantly for both industrial process heat and power generation. This technology has matured over the years, and its advancement has become the topic of numerous research studies which were the counter driving force of the field. Particularly in recent years, a significant amount of theoretical and numerical studies have been conducted to assess and improve the performance of parabolic trough solar collectors. This review methodologically holds colossal knowledge of current and past studies to assess the optical and thermal performances of parabolic trough solar collectors, modeling approaches and the potential improvements proposed on behalf of the parabolic trough solar collector design. The optical modeling approaches are identified to be analytical and ray-tracing. The review of thermal modeling approaches presents the steady and transient heat transfer analyses of single and two-phase (with direct steam generation) flows. Also, the computational fluid dynamics models used to analyze the physics of parabolic trough solar collectors with a better insight are reviewed and presented. Finally, the studies conducted on the performance improvement of parabolic trough solar collectors are separately examined and presented, these include novel designs, passive heat transfer enhancement, and nanoparticle laden flows.Öğe Numerical analysis of the thermal and thermodynamic performance of a parabolic trough solar collector using SWCNTs-Therminol®VP-1 nanofluid(Pergamon-Elsevier Science Ltd, 2018) Mwesigye, Aggrey; Yilmaz, Ibrahim Halil; Meyer, Josua P.In this paper, energetic and exergetic performances of a parabolic trough solar collector using single walled carbon nanotubes (SWCNTs)-Therminol (R) VP-1 nanofluid were numerically investigated and presented. The main objective of this investigation was to determine the influence of high thermal conductivity SWCNTs suspended in the widely used heat transfer fluid, Therminol (R) VP-1 on the performance indicators of the parabolic trough solar collector. A parabolic trough system with a high concentration ratio of 113 was analyzed in this study. The thermo-physical properties of SWCNTs were taken as functions of nanotube length, nanotube diameter, and temperature, while the properties of Therminol (R) VP-1 were considered to be temperature dependent. The study involved determination of the actual heat flux profile through Monte Carlo ray tracing and the subsequent coupling of this heat flux profile to a computational fluid dynamics tool using user defined functions. The computational fluid dynamics tool was finite volume based, and the realizable k-epsilon model together with enhanced wall treatment were used for turbulence modeling. The entropy generation rates were obtained directly from the local velocity and temperature fields of the computed domain and later used in the exergy analysis. Results showed that although the heat transfer performance significantly improved with the use of SWCNTs, the increase in the thermal efficiency was not substantial. For the considered range of parameters, while the heat transfer performance increased up to 234%, the thermal efficiency increased around 4.4% as the volume fraction increased from 0 to 2.5%. The corresponding reduction in the entropy generation was about 70%. (C) 2017 Elsevier Ltd. All rights reserved.Öğe Numerical investigation of the thermo-hydraulic performance of DNA inspired double and triple helix wire coils(Elsevier Science Sa, 2022) Goksu, Taha Tuna; Yilmaz, Ibrahim Halil; Behcet, RasimIn this study, DNA-inspired wire coil (WC) inserts, namely double wire coil (DWC) and triple wire coil (TWC), were proposed for promoting the thermo-hydraulic performance of a plain tube. Triangular-in-shape WC fitted tubes were modeled in Ansys Workbench and numerically solved in Ansys Fluent. WC inserts with pitches (0.056 m, 0.112 m, 0.168 m), side lengths (0.005 m, 0.006 m) and clearance distances (0.001 m, 0.002 m) were analyzed through a fully developed turbulent flow with the Reynolds number ranging from 6,406-26,647. Detailed model validations were performed using the empirical data and experimental studies in the literature and good agreements were statistically achieved. Results reveal that the proposed inserts can significantly increase the heat transfer performance and performance evaluation criterion (PEC) by almost up to fivefold and 103% compared to those of a plain tube, respectively. DWC increases the PEC by similar to 1.1 times the SWC fitted tube while TWC can increase the PEC by similar to 1.14 times. Increasing the number of WC beyond three would not add benefits to the PEC considerably.Öğe Performance Assessment and Solution Procedure for Series Flow Double-Effect Absorption Refrigeration Systems Under Critical Operating Constraints(Springer Heidelberg, 2019) Yilmaz, Ibrahim Halil; Saka, Kenan; Kaynakli, Omer; Kaska, OnderIn this study, the effects of critical operational constraints on the operational domain of a double-effect lithium bromide/water absorption refrigeration system and its performance were investigated. These constraints were determined as the equivalence state of concentrations, the thermal unbalance between the system components of high-pressure condenser and low-pressure generator, freezing and crystallization risk of lithium bromide/water solution. For the system analysis, a simulation program was developed, and its detailed solution procedure was presented. The program outputs were initially validated with the literature. Subsequently, parametric studies were conducted for broad ranges of the component temperatures. The results demonstrate that the considered constraints were essential for acceptable design and the operational control of double-effect absorption refrigeration systems. The simulations will help to figure out under which operating conditions a double-effect absorption refrigeration system functions effectively and what kind of control strategies are essentially required to increase the coefficient of performance. Based on the operation scenario of fixed high-pressure generator temperature, the proposed system can enhance the coefficient of performance up to 31% and 84% as compared to its counterparts which function under the variable high-pressure generator temperature and the pinch point temperature difference (5K between the high-pressure condenser and the low-pressure generator), respectively.Öğe PERFORMANCE TESTING OF A PARABOLIC TROUGH COLLECTOR ARRAY FOR A SMALL-SCALE PROCESS HEAT APPLICATION(Turkish Soc Thermal Sciences Technology, 2018) Yilmaz, Ibrahim Halil; Hayta, Hakan; Yumrutas, Recep; Soylemez, Mehmet SaitThis study presents the experimental investigation on performance testing of a parabolic trough solar collector (PTSC) array consisting of three modules connected in series. A new test setup has been proposed to test the thermal performance of this PTSC array in compliance with ASHRAE 93-1986 standard. The experimental tests have been carried out and monitored in a number of days under cloudless sky conditions in Gaziantep. In the performance analyses, the effects of beam radiation, collector inlet temperature, ambient conditions, and the variation in mass flow rate of the working fluid were investigated. The steady-state and dynamic tests of the PTSC array were performed. The efficiency tests were conducted with thermal oil for the temperature range from 50 degrees C to 200 degrees C, and mass flow rate of 0.1 kg/s to 0.5 kg/s under steady conditions. Additionally, the experimental results were compared with the results of the theoretical study made previously and gave good coherency.Öğe Performance testing of a parabolic trough collector array for a small-scale process heat application(Turk Isı Bilimi ve Teknigi Dernegi, 2018) Yilmaz, Ibrahim Halil; Hayta, Hakan; Yumrutaş, Recep; Söylemez, Mehmet SaitThis study presents the experimental investigation on performance testing of a parabolic trough solar collector (PTSC) array consisting of three modules connected in series. A new test setup has been proposed to test the thermal performance of this PTSC array in compliance with ASHRAE 93-1986 standard. The experimental tests have been carried out and monitored in a number of days under cloudless sky conditions in Gaziantep. In the performance analyses, the effects of beam radiation, collector inlet temperature, ambient conditions, and the variation in mass flow rate of the working fluid were investigated. The steady-state and dynamic tests of the PTSC array were performed. The efficiency tests were conducted with thermal oil for the temperature range from 50 °C to 200 °C, and mass flow rate of 0.1 kg/s to 0.5 kg/s under steady conditions. Additionally, the experimental results were compared with the results of the theoretical study made previously and gave good coherency. © 2018 TIBTD Printed in Turkey.Öğe Pilot-scale hydrogen generation from the hydrolysis of black aluminum dross without any catalyst(Elsevier Sci Ltd, 2022) Kale, Mehmet; Yilmaz, Ibrahim Halil; Kaya, Abdulaziz; Cetin, Ali Emrah; Soylemez, Mehmet SaitThis study presents a sustainable method for the production of hydrogen gas without adding any catalyst from the hydrolysis of black Al dross. A pilot-scale experimental setup consisting of a reactor, a condenser, and control and measurement devices was constructed to perform chemical reactions and physical measurements. The dross used in experiments was not activated by any process and can be found in facilities (Al production plants or die casting factories) with a grain size lower than 400 mu m. The chemical composition revealed by XRF showed that the black dross contained 41.96% Al. Major and minor crystalline phases present in the sample were detected by XRD. A set of experiments was performed to investigate the effects of gravimetric dross to water ratio, pH value, initial water temperature, the pressure of the reaction mixture in time for H-2 synthesis. 120 L of gas were maximally produced after reacting 1 kg of Al dross with 2 kg of hot tap water at 100 degrees C. The H-2 purity of the gas mixture and the calorific value of the mixture were respectively measured by gas chromatography and gas calorimeter as 93.24% and 2375 kcal/m(3). After hydrolysis of the Al dross, XRD, SEM, and EDX analyses revealed the formation of hydrolysis products and their morphology. This showed that the resultant mixture tends to become harmless and can be used for various fields of the industry as a by-product.Öğe Prioritization of heat transfer fluids in parabolic trough solar systems using CFD-assisted AHP-VIKOR approach(Pergamon-Elsevier Science Ltd, 2023) Yilmaz, Ibrahim Halil; Mwesigye, Aggrey; Kılıç, FatihParabolic trough solar collectors (PTSCs) are proven technologies and are used in various fields including concentrating solar power, integrated solar combined cycle, industrial process heat, air conditioning, and desalination. The selection of heat transfer fluid (HTF) is a part of the design consideration of concentrating solar technologies (CST) since its technical specifications have a significant effect on the system configuration, operating conditions, and levelized energy cost. Several HTFs including water, thermal oils, molten salts, and gases are already in use for PTSC systems, and others including liquid metals, ionic liquids, and nanofluids are still being tested. Each HTF has pros and cons; thermal and thermodynamic evaluations are practical to compare the performance of an HTF with that of its counterparts however they are insufficient to attribute a parabolic trough CST in terms of design concerns. This study has presented an integrated AHP-VIKOR (Analytical Hier- archy Process - VIekriterijumsko KOmpromisno Rangiranje) multi-criteria decision making (MCDM) approach assisted by computational fluid dynamics (CFD) to prioritize HTFs, particularly for CST and the results are compared to AHP-TOPSIS (Analytical Hierarchy Process - Technique for Order Preference by Similarity to Ideal Solution) for validation. While AHP is chosen to decide the criteria weights in the multi-criteria process, VIKOR is used as decision making to rank and prioritize alternatives. Water, Therminol VP-1, Solar salt, Hitec, Hitec XL, Liquid sodium, Lead-bismuth eutectic, Carbon dioxide, Air, and Helium are evaluated as the HTF inventory and a comprehensive CFD study is conducted to benchmark their thermal and thermodynamic properties in a high concentration PTSC in terms of solidification temperature, upper thermal stability, collector efficiency, pumping power consumption, receiver temperature gradient, and irreversibilities. In addition, other critical design con- siderations of HTFs including material cost, heat storage capability, material compatibility, operational safety aspects, operational maturity, and solar field control sophistication are taken into account in the MCDM process. Results show that the current parabolic trough CST should have priority for the HTFs of water and molten salt (Hitec) but molten metals and gaseous fluids would gain more insight in near future. This study presents an original perspective for deciding suitable HTFs in PTSC applications where thermal and thermodynamic analyses are limited.Öğe Residential use of solar water heating in Turkey: A novel thermo-economic optimization for energy savings, cost benefit and ecology(Elsevier Sci Ltd, 2018) Yilmaz, Ibrahim HalilRecent trends in residential solar water heating and its efficient usage in Turkey were presented in this study. A novel methodology for determining the optimum orientation and sizing of water-in-glass evacuated tube solar water heating systems has been outlined. Transient modeling was conducted for the prediction of a full year's system performance via the System Advisor Model. In this model, the typical meteorological year data of certain climate zones in Turkey were considered, daily hot water consumption was estimated using the Rand hot water profile, and the monthly averaged mains water temperatures measured by the municipalities were analyzed. In addition, a typical performance rating of a water-in-glass evacuated tube collector produced by the collector manufacturer in Turkey was taken into consideration, and the effects of collector area, storage tank volume, daily average delivery temperature and daily hot water consumption data on the annual solar fraction were analyzed. The verification of the simulation results were compared with the literature and good agreement was obtained. Subsequently, a thermo-economic optimization was employed by using P-1-P-2 methodology. The methodology presented guarantees to obtain reliable results with a minimal run-time. The diminution in the initial system cost and payback period are shown to be possibly achieved at the level of 7.5% in a 1.5 year period, respectively, while the energy savings are approximately 12% higher annually when implementing optimum results. The results indicate that Turkey would save 300 MWth annually if evacuated tube solar water heaters in Turkey's cities are configured based on optimal sizing. An evacuated solar water heater in a typical residential building in Turkey has the potential to mitigate 5-22 g CO2-equivalent/kWh of greenhouse gas emissions per annum if properly installed. (C) 2018 Elsevier Ltd. All rights reserved.Öğe Technology position of concentrating solar technologies in Turkiye: A review on current status, applications, and prospects(Taylor & Francis Inc, 2024) Yilmaz, Ibrahim Halil; Arici, MuslumTurkiye has considerable solar resources and technology capacity and thus is seeking ways to implement carbon-neutral energy policies and reduce import energy. After China, Turkiye has the world's second-largest installed nonconcentrating collector area. Since the last quarter, significant efforts have been made in Turkiye to implement concentrated solar technologies (CST), including the world's largest industrial solar energy cooling system and the first solar thermal trigeneration system, the first integrated renewables combined cycle, as well as more efficient two-axis tracking parabolic trough systems. This review highlights the overall status, developments, research trends, breakthroughs, technology deployment, challenges, and prospects of the commercial Turkish CST. It aims to present the historical development of CST and associated research activities conducted and ongoing in Turkiye, infrastructure of national organizations, a pathway for the alignment of national/global research and funding programs, and commercial-level contributions for the future progress of CST. It would also bridge the gap between the research and commercial deployment of CST and speed up the relevant transfer of knowledge so that researchers, institutions, companies, decision-makers, and other stakeholders in Turkiye and the world can gain a greater perspective. Although considerable efforts have been made in the Turkish CST context, similar to 10-MWt cumulative capacity is actively operated, of similar to 60% and similar to 32% led, respectively, by the parabolic trough and central tower receiver technologies.Öğe Thermal and thermodynamic benchmarking of liquid heat transfer fluids in a high concentration ratio parabolic trough solar collector system(Elsevier, 2020) Mwesigye, Aggrey; Yilmaz, Ibrahim HalilThe thermal oil-based heat transfer fluids (HTFs) used in parabolic trough solar collector (PTSC) systems suffer from degradation at temperatures above 400 degrees C, limiting the thermal efficiencies of these systems. As such, several researchers have investigated various HTFs for high-temperature applications of PTSCs. In this study, the thermal and thermodynamic performance of a PTSC system with a geometrical concentration ratio of 113 is numerically investigated. The developed and thorough validated numerical model combines Monte-Carlo ray tracing and computational fluid dynamics for optical analysis, and thermal and thermodynamic studies, respectively. Ten HTFs with temperature-dependent thermal physical properties are considered. They are -Liquid metals: liquid sodium, Lead-Bismuth Eutectic (LBE), -Molten salts: Solar Salt, Hitec, Hitec XL, a ternary salt mixture: LiNO3 + NaNO3 + KNO3 (18 wt%, 52 wt%. and 30 wt%), a quaternary salt mixture: NaNO3 + KNO3 + LiNO3 + Ca(NO3)(2) (9 wrI, 54 wt%, 18 wt%, and 18 wt%), a new salt mixture: NaCI+KCI + ZnCl2 (7.5 wt%, 23.9 wt%, and 68.6 wt%), and -Thermal oils: The rm inol VP-1 and Dowtherm A. Results show that liquid sodium gives the best thermal, hydraulic, and thermodynamic performance of the considered HTFs at all flow rates and inlet temperatures. LBE gives the second highest heat transfer performance, however, its thermal and thermodynamic performance degrade as flow rates increase above 32.75 m(3)/h owing to the high pumping power and fluid flow irreversibilities. As liquid sodium and LBE are expensive, LiNO3 + NaNO3 + KNO3 (18 wt %, 52 wt%, and 30 wt%) shows better overall performance as compared with other molten salts. Moreover, it possesses a low melting point and high thermal stability temperature. In addition, the thermal efficiency is within +/- 0.4% for molten salts at flow rates between 16 and 36 m(3)/h that give optimal performance. (C) 2020 Elsevier B.V. All rights reserved.
