Yousef Belloufi, Amar Rouag, Faris Aissaoui, Abdelmoumene-Hakim Benmachiche, Abdelhfid Brima
Abstract In this research study, the development of a theoretical model to estimate the efficiency of a double pass solar air heater (DPSAH) was the main objective. The mathematical model was compared to experimental results and found to be in agreement, both qualitatively and quantitatively. The model used energy balance equations to determine the outlet temperature and could solve the temperature equations of each component of the heater simultaneously. A matrix inversion method was used for this purpose. The study found that increasing the Nusselt number led to an increase in energy efficiency, but also caused a drop in outlet temperature at any solar radiation. The mass flow rate (MFR), with larger flow rates resulting in better efficiencies, had a significant impact on the double pass air heater’s efficiency. Thus, increasing of DPSAH’s length increases its thermal performances and reach its maximum values for L=9m. These findings could be beneficial in selecting the most efficient design parameters for DPSAH.
{"title":"Thermal Performance of Double Pass Solar Air Collector: Numerical and Experimental Investigation","authors":"Yousef Belloufi, Amar Rouag, Faris Aissaoui, Abdelmoumene-Hakim Benmachiche, Abdelhfid Brima","doi":"10.2478/awutp-2023-0010","DOIUrl":"https://doi.org/10.2478/awutp-2023-0010","url":null,"abstract":"Abstract In this research study, the development of a theoretical model to estimate the efficiency of a double pass solar air heater (DPSAH) was the main objective. The mathematical model was compared to experimental results and found to be in agreement, both qualitatively and quantitatively. The model used energy balance equations to determine the outlet temperature and could solve the temperature equations of each component of the heater simultaneously. A matrix inversion method was used for this purpose. The study found that increasing the Nusselt number led to an increase in energy efficiency, but also caused a drop in outlet temperature at any solar radiation. The mass flow rate (MFR), with larger flow rates resulting in better efficiencies, had a significant impact on the double pass air heater’s efficiency. Thus, increasing of DPSAH’s length increases its thermal performances and reach its maximum values for L=9m. These findings could be beneficial in selecting the most efficient design parameters for DPSAH.","PeriodicalId":479583,"journal":{"name":"Annals of West Univesity of Timişoara","volume":"12 17","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135139450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The primary goal of this paper is to assess the thermal behaviour of Earth-to-Air Heat Exchanger (EAHE) under continuous operation mode during the cooling period in warm climatic conditions. An experimental setup was conducted in Biskra University (Algeria) to test the ability to use EAHE as an alternative solution to conventional air conditioning systems. Besides, a transient numerical approach for the flowing air within the EAHE was developed using energy balance equations, discretised by the implicit finite differences method and solved by Thomas method. Furthermore, the transient temperature profile of the soil around the EAHE was investigated in order to determine the adiabatic radius of the soil as a function of the duration of operation. In this context, a transient semi-analytical model was integrated to the air model to estimate the transient EAHE’s performance deterioration. This deterioration is produced by the thermal saturation of the soil, which is influenced by the heat released from the air inside the pipe. Results showed that continuous operation for a duration of four days has minimal impact on the outlet air temperatures due to the implementation of night purging. Furthermore, the design and thermal efficiency of the EAHE are impacted by factors such as higher air velocity and reduced soil thermal conductivity.
{"title":"Experimental and Hybrid Numerical Analytical Approach of an Earth-to-Air Heat Exchanger","authors":"Faris Aissaoui, Amar Rouag, Yousef Belloufi, Sakina Zerouali, Rachid Atmani, Adel Benchabane, Abdelhafid Brima, Noureddine Moummi, Djamel Belatrache","doi":"10.2478/awutp-2023-0008","DOIUrl":"https://doi.org/10.2478/awutp-2023-0008","url":null,"abstract":"Abstract The primary goal of this paper is to assess the thermal behaviour of Earth-to-Air Heat Exchanger (EAHE) under continuous operation mode during the cooling period in warm climatic conditions. An experimental setup was conducted in Biskra University (Algeria) to test the ability to use EAHE as an alternative solution to conventional air conditioning systems. Besides, a transient numerical approach for the flowing air within the EAHE was developed using energy balance equations, discretised by the implicit finite differences method and solved by Thomas method. Furthermore, the transient temperature profile of the soil around the EAHE was investigated in order to determine the adiabatic radius of the soil as a function of the duration of operation. In this context, a transient semi-analytical model was integrated to the air model to estimate the transient EAHE’s performance deterioration. This deterioration is produced by the thermal saturation of the soil, which is influenced by the heat released from the air inside the pipe. Results showed that continuous operation for a duration of four days has minimal impact on the outlet air temperatures due to the implementation of night purging. Furthermore, the design and thermal efficiency of the EAHE are impacted by factors such as higher air velocity and reduced soil thermal conductivity.","PeriodicalId":479583,"journal":{"name":"Annals of West Univesity of Timişoara","volume":"119 34","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135137211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this work, the main object of this research is to investigate a new material based on ZnS and NiS nanostructures. NiS and ZnS solutions were sprayed on the heated Low Carbon Steel by a spray pneumatic deposition method. Electrochemical analyses of the prepared samples were investigated. The high corrosion resistance of coated by ZnS sample have a low value of surface roughness. However, the coated sample by ZnS also has good stabilization after corrosion and high compact of the film.
{"title":"Corrosion Resistance of NiS, ZnS and NiS/ZnS Thin Films Deposited by Spray Pyrolysis Technique on Low Carbon Steel in 3.5%Nacl Solution","authors":"Kamel Djail, Said Benramache","doi":"10.2478/awutp-2023-0009","DOIUrl":"https://doi.org/10.2478/awutp-2023-0009","url":null,"abstract":"Abstract In this work, the main object of this research is to investigate a new material based on ZnS and NiS nanostructures. NiS and ZnS solutions were sprayed on the heated Low Carbon Steel by a spray pneumatic deposition method. Electrochemical analyses of the prepared samples were investigated. The high corrosion resistance of coated by ZnS sample have a low value of surface roughness. However, the coated sample by ZnS also has good stabilization after corrosion and high compact of the film.","PeriodicalId":479583,"journal":{"name":"Annals of West Univesity of Timişoara","volume":"53 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135092742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this paper, we have performed a theoretical study using the linear augmented and linearized plane wave method (FP-LAPW) implemented in the Wien2k computational code based on density functional theory (DFT) to determine the structural, electronic and optical properties of GdAlO 3 and DyAlO 3 perovskites. The exchange and correlation potential are treated by the generalized gradient approximation of Perdew-Burke-Ernzerhof (GGA-PBE) and modified Becke-Johnson potential (mBJ). The structural properties such as lattice parameter, modulus of compressibility and its derivative are in good agreement with other theoretical results. The electronic properties, such as band structure and density of state revealed an indirect energy gap in the L - xG direction for GdAlO 3 , with gap values of 2.879 eV (GGA-PBE), 5.006 eV (mBJ) in spin-up and 2.286 eV (mBJ), 2.736 eV (mBJ) in spin-dn.for DyAlO 3 perovskite, due to the over lap of the valence and conduction bands at Fermi level, which behaves like a metal oxide. We have also calculated the optical properties of these two compounds, such as dielectric function, refractive index, absorption coefficient and optical conductivity. They indicate that GdAlO 3 and DyAlO 3 perovskites could be useful for applications in UV photo catalysis.
本文基于密度泛函理论(DFT)，利用Wien2k计算代码中实现的线性增广和线性化平面波方法(FP-LAPW)进行了理论研究，以确定gdalo3和DyAlO 3钙钛矿的结构、电子和光学性质。交换势和相关势采用广义梯度近似Perdew-Burke-Ernzerhof势(GGA-PBE)和修正的Becke-Johnson势(mBJ)进行处理。晶格参数、压缩模量及其导数等结构性质与其他理论结果吻合较好。GdAlO 3的能带结构和态密度等电子性质表明，GdAlO 3在L - xG方向存在间接能隙，自旋向上的能隙值为2.879 eV (GGA-PBE)、5.006 eV (mBJ)，自旋向下的能隙值为2.286 eV (mBJ)、2.736 eV (mBJ)。对于dyalo3钙钛矿，由于价带和导带在费米能级重叠，其行为类似于金属氧化物。我们还计算了这两种化合物的介电函数、折射率、吸收系数和光电导率等光学性质。结果表明，gdalo3和dyalo3钙钛矿可用于紫外光催化。
{"title":"Structural and Optoelectronic Properties of Cubic Perovskite Type XAlO<sub>3</sub> (X = Gd and Dy) Theoretical Investigation","authors":"Bouhenna Abdelkder, Benyahia Karima, Beloufa Nabil, Boualem Kada, Bekheira Samir","doi":"10.2478/awutp-2023-0011","DOIUrl":"https://doi.org/10.2478/awutp-2023-0011","url":null,"abstract":"Abstract In this paper, we have performed a theoretical study using the linear augmented and linearized plane wave method (FP-LAPW) implemented in the Wien2k computational code based on density functional theory (DFT) to determine the structural, electronic and optical properties of GdAlO 3 and DyAlO 3 perovskites. The exchange and correlation potential are treated by the generalized gradient approximation of Perdew-Burke-Ernzerhof (GGA-PBE) and modified Becke-Johnson potential (mBJ). The structural properties such as lattice parameter, modulus of compressibility and its derivative are in good agreement with other theoretical results. The electronic properties, such as band structure and density of state revealed an indirect energy gap in the L - xG direction for GdAlO 3 , with gap values of 2.879 eV (GGA-PBE), 5.006 eV (mBJ) in spin-up and 2.286 eV (mBJ), 2.736 eV (mBJ) in spin-dn.for DyAlO 3 perovskite, due to the over lap of the valence and conduction bands at Fermi level, which behaves like a metal oxide. We have also calculated the optical properties of these two compounds, such as dielectric function, refractive index, absorption coefficient and optical conductivity. They indicate that GdAlO 3 and DyAlO 3 perovskites could be useful for applications in UV photo catalysis.","PeriodicalId":479583,"journal":{"name":"Annals of West Univesity of Timişoara","volume":"16 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135137019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The present work aims to investigate the structural and thermodynamic properties of homogenous tetragonal Cu 2 ZnSnS 4 (CZTS) absorber material in Kesterite phase using first-principle calculations based on density functional theory (DFT). This approach requires only knowledge of the atomic species and crystal structure to predict several physical properties of materials. The Quantum Espresso code within the Ultra Soft pseudopotentials (USPP) and the local density approximation (LDA) were used in the calculations. Equilibrium unit cell volumes, bulk modulus, as well as the pressure derivative of the bulk modulus are predicted. In addition, several thermodynamic properties, especially: the Debye’s vibrational energy, the vibrational free energy, the vibrational entropy, and the constant volume heat capacity at different temperatures T of Cu 2 ZnSnS 4 material are calculated and discussed. Our study shows that the vibrational energy, the entropy and the constant volume heat capacity increase with increasing temperature, while the vibrational free energy decreases monotonously with the increase of temperature.
{"title":"Structural and Thermodynamic Properties of Cu<sub>2</sub>ZnSnS<sub>4</sub> Material: Theoretical Prediction","authors":"L. Boutahar, A. Benamrani, Z. Rouabah, S. Daoud","doi":"10.2478/awutp-2023-0012","DOIUrl":"https://doi.org/10.2478/awutp-2023-0012","url":null,"abstract":"Abstract The present work aims to investigate the structural and thermodynamic properties of homogenous tetragonal Cu 2 ZnSnS 4 (CZTS) absorber material in Kesterite phase using first-principle calculations based on density functional theory (DFT). This approach requires only knowledge of the atomic species and crystal structure to predict several physical properties of materials. The Quantum Espresso code within the Ultra Soft pseudopotentials (USPP) and the local density approximation (LDA) were used in the calculations. Equilibrium unit cell volumes, bulk modulus, as well as the pressure derivative of the bulk modulus are predicted. In addition, several thermodynamic properties, especially: the Debye’s vibrational energy, the vibrational free energy, the vibrational entropy, and the constant volume heat capacity at different temperatures T of Cu 2 ZnSnS 4 material are calculated and discussed. Our study shows that the vibrational energy, the entropy and the constant volume heat capacity increase with increasing temperature, while the vibrational free energy decreases monotonously with the increase of temperature.","PeriodicalId":479583,"journal":{"name":"Annals of West Univesity of Timişoara","volume":"3 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Deterioration of treated drinking water intended for consumption during distribution may be due to physical, chemical or microbiological changes that occur in the water. In addition, the type of pipe material and disintegration of a disinfectant agent can affect the quality of the water supplied. Therefore, the research approach is to simulate the decay residual Cl 2 through potable water distribution networks produced by a desalination plant of Oran city in western Algeria. EPANET 2.0 software was used for estimating and predicting Cl 2 concentration at different water network points. The value of bulk flow decay coefficient (Kb) is set to -1,99 day -1 for a 50-year-old steel pipe, value for the wall decay coefficient (Kw) was determined using a trial-and-error procedure and assumed to be -1,2 day -1 . An efficient model with an extended simulations period of 72 h can plot spatial and temporal variations of residual Cl 2 concentrations at all links and nodes. Cl 2 is injected at the El Mactaa desalination plant, with a concentration of 0.6 mg/l permanently. As well, it was observed that 51.33% of the Cl 2 loss is due to pipe wall reaction, while 42.34 and 6.33% represent the bulk and tank reactions respectively. The results show that the range of residual Cl 2 (0.11-0,45 mg/l) and most of the measured values are less than are below the minimum authorized threshold (0.2 – 0.5 mg/l) WHO standard. Therefore, it is recommended to rehabilitate the old water transfer pipes and re-chlorination stations were necessary to add into network. Statistical analysis shows that the calculated results correspond well to the observed data. EPANET can follow the Cl 2 concentration in the drinking water network produced by El Mactaa desalination plant. It is a research tool to improve our understanding of water movement in the distribution system.
{"title":"Chlorine Decay Simulation in Real Water Distribution System Using EPANET Program","authors":"Mekki Malika, Bouabdesselam Hassiba, Laib Radouane, Beloufa Nabil, Bekheira Samir, Mohamed Trari","doi":"10.2478/awutp-2023-0007","DOIUrl":"https://doi.org/10.2478/awutp-2023-0007","url":null,"abstract":"Abstract Deterioration of treated drinking water intended for consumption during distribution may be due to physical, chemical or microbiological changes that occur in the water. In addition, the type of pipe material and disintegration of a disinfectant agent can affect the quality of the water supplied. Therefore, the research approach is to simulate the decay residual Cl 2 through potable water distribution networks produced by a desalination plant of Oran city in western Algeria. EPANET 2.0 software was used for estimating and predicting Cl 2 concentration at different water network points. The value of bulk flow decay coefficient (Kb) is set to -1,99 day -1 for a 50-year-old steel pipe, value for the wall decay coefficient (Kw) was determined using a trial-and-error procedure and assumed to be -1,2 day -1 . An efficient model with an extended simulations period of 72 h can plot spatial and temporal variations of residual Cl 2 concentrations at all links and nodes. Cl 2 is injected at the El Mactaa desalination plant, with a concentration of 0.6 mg/l permanently. As well, it was observed that 51.33% of the Cl 2 loss is due to pipe wall reaction, while 42.34 and 6.33% represent the bulk and tank reactions respectively. The results show that the range of residual Cl 2 (0.11-0,45 mg/l) and most of the measured values are less than are below the minimum authorized threshold (0.2 – 0.5 mg/l) WHO standard. Therefore, it is recommended to rehabilitate the old water transfer pipes and re-chlorination stations were necessary to add into network. Statistical analysis shows that the calculated results correspond well to the observed data. EPANET can follow the Cl 2 concentration in the drinking water network produced by El Mactaa desalination plant. It is a research tool to improve our understanding of water movement in the distribution system.","PeriodicalId":479583,"journal":{"name":"Annals of West Univesity of Timişoara","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135734858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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