Energy Systems Engineering / Enerji Sistemleri Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4752
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Article Citation - WoS: 2Citation - Scopus: 2Bayesian Uncertainty Quantification in Temperature Simulation of Borehole Heat Exchanger Fields for Geothermal Energy Supply(Pergamon-Elsevier Science Ltd, 2025) Mohammadi, Hesam Soltan; Ringel, Lisa Maria; Bott, Christoph; Erol, Selcuk; Bayer, PeterAccurate temperature prediction is crucial for optimizing the performance of borehole heat exchanger (BHE) fields. This study introduces an efficient Bayesian approach for improving the forecast of temperature changes in the ground caused by the operation of BHEs. The framework addresses the complexities of multi-layer subsurface structures and groundwater flow. By utilizing an affine invariant ensemble sampler, the framework estimates the distribution of key parameters, including heat extraction rate, thermal conductivity, and Darcy velocity. Validation of the proposed methodology is conducted through a synthetic case involving four active and one inactive BHE over five years, using monthly temperature changes around BHEs from a detailed numerical model as a reference. The moving finite line source model with anisotropy is employed as the forward model for efficient temperature approximations. Applying the proposed methodology at a monthly resolution for less than three years reduces uncertainty in long-term predictions by over 90%. Additionally, it enhances the applicability of the employed analytical forward model in real field conditions. Thus, this advancement offers a robust tool for stochastic prediction of thermal behavior and decision-making in BHE systems, particularly in scenarios with complex subsurface conditions and limited prior knowledge.Erratum Author Correction: the Influence of Nano Filter Elements on Pressure Drop and Pollutant Elimination Efficiency in Town Border Stations(Nature Research, 2023) Heris, S.Z.; Ebadiyan, H.; Mousavi, S.B.; Nami, S.H.; Mohammadpourfard, MousaThe original version of this Article contained an error in the order of the author names, which was incorrectly given as Hamed Ebadiyan, Saeed Zeinali Heris, Seyed Borhan Mousavi, Shamin Hosseini Nami & Mousa Mohammadpourfard. Consequently, in the Author Contributions section, “H.E. Investigation. S.Z.H. Supervision, Conceptualization, Methodology, Validation. S.B.M. Formal analysis, Writing original draft. S.H.N. Formal analysis, Writing original draft. M.M. Validation.” now reads: “S.Z.H. Supervision, Conceptualization, Methodology, Validation. H.E. Investigation. S.B.M. Formal analysis, Writing original draft. S.H.N. Formal analysis, Writing original draft. M.M. Validation.” The original Article has been corrected. © 2023, The Author(s).Article Citation - WoS: 7Citation - Scopus: 7Dynamic Development of Geochemical Reaction Fronts During Hydraulic Stimulation of Shale(Elsevier, 2023) Noel, Vincent; Druhan, Jennifer L.; Gündoğar, Aslı; Kovscek, Anthony R.; Brown Jr, Gordon E.; Bargar, John R.Injection of acidic hydraulic fracture fluid (HFF) into shale formations for unconventional oil/gas production results in chemical reactions in the shale matrix that can alter fluid transport. Here, we report the results of set of experiments designed to evaluate the impact of calcite dissolution as a function of carbonate mineral content on matrix chemical reactivity and pore-space modification concomitant with imbibition. We tracked acidic HFF transport in four samples of Wolfcamp shale with calcite contents varying from 4% to 59% by monitoring the rate and spatial extent of bromide tracer transport using synchrotron-based X-ray fluorescence microprobe (XFM) imaging. Concurrently, we also carried out XFM imaging of the spatial distribution of Ca in the Wolfcamp shale cores (as a proxy of calcite distribution). Our approach thus yields a direct record of time-resolved selective ion transport resulting from the penetration of acidic HFF and the associated mineral transformations in the shale cores. We show that the variability in calcite content of Wolfcamp shale samples can directly affect the rate and spatial extent of imbibition. Although reaction of the acidic HFF with carbonates in shales enhances calcite dissolution and increases porosity, the spatial extent of calcite dissolution in the shale matrix is limited due to a rapid neutralization of pH. The relative abundance and spatial distribution of calcite control the chemical saturation state of the HFF progressing into the matrix. As a result, calcite has a major impact on the spatial extent and rate of matrix alteration and thus on HFF transport during subsurface reservoir stimulation. Consequently, increased calcite content in the shale matrix inhibits the spatial extent of the pore-volume increase and, by extension, the spatial extent and rate of imbibition. Our results thus show that the overall rates of calcite dissolution approach the rates of acidic HFF transport (i. e., Damko spacing diaeresis hler number similar to 1), which could contribute to the efficiency of subsurface reservoir stimulation. A better understanding of HFF-calcite reaction rates is crucial for improving the prediction and optimization of fluid transport across HFF-shale interfaces during hydraulic fracturing.Article Citation - WoS: 45Citation - Scopus: 51Experimental Investigation of the Effect of Graphene/Water Nanofluid on the Heat Transfer of a Shell-And Heat Exchanger(Wiley-Hindawi, 2023) Zolfalizadeh, Mehrdad; Heris, Saeed Zeinali; Pourpasha, Hadi; Mohammadpourfard, Mousa; Meyer, Josua P. P.The most common type of heat exchanger used in a variety of industrial applications is the shell-and-tube heat exchanger (STHE). In this work, the impact of graphene nanoplate (GNP)/water nanofluids at 0.01 wt.%, 0.03 wt.%, and 0.06 wt.% on the thermal efficiency, thermal performance factor, pressure drop, overall heat transfer, convective heat transfer coefficient (CVHTC), and heat transfer characteristics of a shell-and-tube heat exchanger was examined. For these experiments, a new STHE was designed and built. The novelty of this study is the use of GNPs/water nanofluids in this new STHE for the first time and the fully experimental investigation of the attributes of nanofluids. GNP properties were analysed and confirmed using analyses including XRD and TEM. Zeta potential, DLS, and camera images were used to examine the stability of nanofluids at various periods. The zeta potential of the nanofluids was lower than -27.8 mV, confirming the good stability of GNP/water nanofluids. The results illustrated that the experimental data for distilled water had a reasonably good agreement with Sieder-Tate correlation. The maximum enhancement in the CVHTC of nanofluid with 0.06 wt.% of GNP, was equal to 910 (W/m(2)K), an increase of 22.47%. Also, the efficiency of the heat exchanger for nanofluid at 0.06 wt.% improved by 8.88% compared with that of the base fluid. The heat transfer rate of the nanofluid at maximum concentration and volume flow rate was 3915 (J/kg.K), an improvement of 15.65% over the base fluid. The pressure drops increased as the flow rate and concentration of the nanofluid increased. Although increasing the pressure drop in tubes would increase the CVHTC, it would also increase the power consumption of the pump. In conclusion, nanofluid at 0.06 wt.% had good performance.Article Citation - WoS: 52Citation - Scopus: 60Applied Machine Learning for Prediction of Waste Plastic Pyrolysis Towards Valuable Fuel and Chemicals Production(Elsevier, 2023) Cheng, Yi; Yang, Yang; Coward, Brad; Wang, Jiawei; Yıldız, Güray; Ekici, Ecrin; Yıldız, GürayPyrolysis is a suitable conversion technology to address the severe ecological and environmental hurdles caused by waste plastics' ineffective pre- and/or post-user management and massive landfilling. By using machine learning (ML) algorithms, the present study developed models for predicting the products of continuous and non-catalytically processes for the pyrolysis of waste plastics. Along with different input datasets, four algorithms, including decision tree (DT), artificial neuron network (ANN), support vector machine (SVM), and Gaussian process (GP), were compared to select input variables for the most accurate models. Among these algorithms, the DT model exhibited generalisable and satisfactory accuracy (R2 > 0.99) with training data. The dataset with the elemental composition of waste plastics achieved better accuracy than that with the plastic-type for predicting liquid yields. These observations allow the predictions by the data from ultimate analysis when inaccessible to the plastic-type data in unknown plastic wastes. Besides, the combination of ultimate analysis input and the DT model also achieved excellent accuracy in liquid and gas composition predictions. © 2023 The AuthorsArticle Citation - WoS: 30Citation - Scopus: 32Improving the Thermal Characteristics of a Cooling Tower by Replacing the Operating Fluid With Functionalized and Non-Functionalized Aqueous Mwcnt Nanofluids(Elsevier, 2022) Karimi Bakhtiyar, Nazanin; Javadpour, Reza; Zeinali Heris, Saeed; Mohammadpourfard, MousaIn this study, the thermal properties of the operating fluid by replacing the fluid with better thermal properties and lower water loss in a cross-flow cooling tower (CFWCT) investigated. For this purpose, MWCNTs/H2O, MWCNTs-COOH/H2O, and MWCNTs-OH/H2O nanofluids were used instead of water, and the results were compared. The visual method and dynamic light scattering (DLS) were used to guarantee the stability of nanofluids and to determine the size distribution of the nanoparticles in the nanofluid. The influence of nanofluids concentration on cooling towers performance variables such as evaporation rate, performance characteristics, temperature drop, and tower efficiency were investigated. The results showed that the functionalized nanofluids with lower evaporation rates than water and the non-functionalized nanofluids with higher evaporation rates than water improved the thermal performance of CFWCT. For example, at a concentration of 0.1 wt% MWCNTs-COOH/H2O, MWCNTs-OH/H2O, and MWCNTs/H2O, the efficiency of the cooling tower was 46%, 45.3%, and 43.2%, and the performance characteristics were improved by 15.8%, 11.2%, and 6.1%, respectively, compared with water. Among the nanofluids, MWCNTs-COOH/H 2 O nanofluid had the best performance, in which the evaporation rate, performance characteristics, temperature drop, and efficiency were increased by about -4.3%, 15.8%, 15.9%, and 8.7%, respectively, compared to water.Article Citation - WoS: 58Citation - Scopus: 76Utilization of Renewable Energy Sources in Desalination of Geothermal Water for Agriculture(Elsevier, 2021) Tomaszewska, Barbara; Gökçen Akkurt, Gülden; Kaczmarczyk, Michal; Bujakowski, Wieslaw; Keleş, Nazlı; Jarma, Yakubu A.; Baba, Alper; Bryjak, Marek; Kabay, NalanThe agricultural sector, which is highly dependent on water, is urged to build on improved water management practices and explore available options to match supply and demand because of the water scarcity risks and a sustainable and productive agri-food chain. Geothermal water is an energy source used to generate electricity and/or heat. After harnessing its energy, the remaining water can be used as a water source for irrigation following treatment because of its high ionic content. Geothermal fields are mostly located in rural areas where agricultural activities exist. This would be a good match to decrease the transportation cost of irrigation water. The energy demand of the desalination process for agriculture is higher, requiring additional post-treatment processes. Fossil fuels to fulfill the energy requirements are becoming expensive, and greenhouse gas emissions are harmful to the environment. Thus, efforts should be directed towards integrating renewable energy resources into desalination process. This work focuses on presenting a comprehensive review of geothermal water desalination which is powered by renewable energy and provides specific cases from Turkey and Poland. Furthermore, possible new generation renewable energy systems in desalination are introduced, considering their potential application in the desalination of geothermal water for agricultural irrigation.Article Citation - WoS: 15Citation - Scopus: 19Ex Situ Catalytic Fast Pyrolysis of Lignin-Rich Digested Stillage Over Na/Zsm-5, H/Zsm-5, and Fe/Zsm-5(American Chemical Society, 2020) Priharto, Neil; Ghysels, Stef; Opsomer, Wim; Ronsse, Frederik; Prins, Wolter; Pala, Mehmet; Yıldız, GürayThe global increase in lignocellulosic ethanol production goes in tandem with an increase in lignin-rich stillage that remains underutilized to date. Anaerobic digestion could valorize residual (biodegradable) organic fractions into biogas, leaving a lignin-rich digested stillage (LRDS). This LRDS from the lignocellulosic ethanol production has been assessed as a feedstock for slow and fast pyrolysis in earlier studies, with the intention to increase the overall output of useful products or energy carriers from the starting material. While using this lignin-rich feedstock, ex situ catalytic vapor-phase upgrading (VPU) of fast pyrolysis vapors with fractional condensation was conducted over Na/ZSM-5, H/ZSM-5, and Fe/ZSM-5 catalysts. Semicontinuous fast pyrolysis experiments have been carried out at a reaction temperature of 480 degrees C in a mechanically stirred sand bed, which was connected directly to a fixed bed of catalyst particles for ex situ upgrading of the fast pyrolysis vapors. The carbon and mass yields in heavy phase liquids decreased after catalytic VPU (mass: ca. 8-11 wt %; carbon: ca. 11-15 wt %), compared to noncatalytic pyrolysis (mass: ca. 18 wt %; carbon: ca. 23 wt %). However, the yield in specific compounds, that is, alkylphenols and aromatics such as BTX, increased much upon catalytic VPU (especially for Fe/ZSM-5). For Fe/ZSM-5, the concentration in alkylphenols and aromatics was 20.8 wt % on liquid basis and the yield was 1.7 wt % on as-received (a.r.) feedstock basis. For noncatalytic pyrolysis, the concentration in alkylphenols and aromatics was 2.1 wt % (liquid basis) with a yield of 0.4 wt % (a.r. feedstock basis). This study thus demonstrates the potential of (modified) catalysts to upgrade lignin pyrolysis vapors.Article Citation - WoS: 22Citation - Scopus: 24Size Dependent Influence of Contact Line Pinning on Wetting of Nano-textured/Patterned Silica Surfaces(Royal Society of Chemistry, 2020) Özçelik, H. Gökberk; Satıroğlu, Ezgi; Barışık, MuratWetting behavior on a heterogeneous surface undergoes contact angle hysteresis as the droplet stabilized at a metastable state with a contact angle significantly different from its equilibrium value due to contact line pinning. However, there is a lack of consensus on how to calculate the influence of pinning forces. In general, the pinning effect can be characterized as (i) microscopic behavior when a droplet is pinned and the contact angle increases/decreases as the droplet volume increases/decreases and (ii) macroscopic behavior as the pinning effects decrease and ultimately, disappear with the increase of the droplet size. The current work studied both behaviors using molecular dynamics (MD) simulation with more than 300 different size water droplets on silica surfaces with three different patterns across two different wetting conditions. Results showed that the contact angle increases linearly with increasing droplet volume through the microscopic behavior, while the droplet is pinned on top of a certain number of patterns. When we normalized the droplet size with the corresponding pattern size, we observed a "wetting similarity" that linear microscopic contact angle variations over different size heterogeneities continuously line up. This shows that the pinning force remains constant and the resulting pinning effects are scalable by the size ratio between the droplet and pattern, independent of the size-scale. The slope of these microscopic linear variations decreases with an increase in the droplet size as observed through the macroscopic behavior. We further found a universal behavior in the variation of the corresponding pinning forces, independent of the wetting condition. In macroscopic behavior, pinning effects become negligible and the contact angle reaches the equilibrium value of the corresponding surface when the diameter of the free-standing droplet is approximately equal to 24 times the size of the surface structure. We found that the pinning effect is scalable with the droplet volume, not the size of the droplet base.Article Citation - WoS: 44Citation - Scopus: 45Carbon Nanotube-Graphene Supported Bimetallic Electrocatalyst for Direct Borohydride Hydrogen Peroxide Fuel Cells(Elsevier Ltd., 2021) Uzundurukan, Arife; Akça, Elif Seda; Budak, Yağmur; Devrim, YılserAt present study, carbon nanotube-graphene (CNT-G) supported PtAu, Au and Pt catalysts were prepared by microwave-assisted synthesis method to investigate the direct liquid-fed sodium borohydride/hydrogen peroxide (NaBH4/H2O2) fuel cell performance. Prepared catalysts were characterized by TGA, XRD, TEM, ICP-OES, cyclic voltammetry and rotating disc electrode (RDE) voltammetry. The catalysts were tested in a single NaBH4/H2O2 fuel cell with 25 cm2 active area to evaluate fuel cell performance. The effects of temperature and fuel concentration on fuel cell performance were examined to observed best operating conditions. As a result of direct NaBH4/H2O2 fuel cell experiments, maximum power densities of 139 mW/cm2, 125 mW/cm2 and 113 mW/cm2 were obtained for PtAu/CNT-G, Au/CNT-G and Pt/CNT-G catalysts, respectively. PtAu/CNT-G catalyst showed the enhanced NaBH4/H2O2 fuel cell performance, which was higher than the Pt/CNT-G catalyst and Au/CNT-G catalyst at 50 °C. The enhanced NaBH4/H2O2 performance can be attributed to synergistic effects between Pt and Au particles on CNT-G support providing a better catalyst utilization and interaction. These results suggest that the prepared PtAu/CNT-G catalyst is a promising anode catalyst for NaBH4/H2O2 fuel cell application. © 2020 Elsevier Ltd