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دسترسی آزاد مقاله
1 - بررسی قابلیت بکارگیری استاندارد توسعه گر منابع انسانی در سازمانهای اداری (مطالعه موردی: سازمان های اداری قزوین)
مرتضی موسی خانی داود حق خواه رقیه حسن زادهاین مقاله حاصل یک مطالعه موردی استاندارد توسعه گر منابع انسانی یا PD می باشد، در این تحقیق پس از بررسی استانداردهای توسعه منابع انسانی (الگوهای IIP و PCMM) به معرفی و بحث مختصر در مورد اصول و شاخصهای استاندارد PD پرداخته شده و قابلیت به کارگیری استاندارد توسعه گر منابع چکیده کاملاین مقاله حاصل یک مطالعه موردی استاندارد توسعه گر منابع انسانی یا PD می باشد، در این تحقیق پس از بررسی استانداردهای توسعه منابع انسانی (الگوهای IIP و PCMM) به معرفی و بحث مختصر در مورد اصول و شاخصهای استاندارد PD پرداخته شده و قابلیت به کارگیری استاندارد توسعه گر منابع انسانی در سازمانهای اداری بررسی و وضعیت سازمان مورد نظر ا ز لحاظ میزان حصول PD مورد سنجش قرار گرفته و سطح این سازمان ارزیابی گردیده است و میزان فاصله سازما ن های مورد نظر با استاندارد مورد نظر مشخص گردیده و در نهایت به ارائه راهکار پرداخته شده است. پرونده مقاله -
دسترسی آزاد مقاله
2 - Theoretical study of the solvent effects on the thermodynamic functions of Alanine and Valine Amino Acids
farideh Keshavarz RezaeiUsing Gaussian 03, software the thermodynamic functions such as Gibbs free energy, G, Enthalpy, H, and Entropy, S, of Alanine and Valine amino acids were theoretically studied at different solvents. First, the Density Functional Theory (B3LYP) level with 3-21G, 6-31G چکیده کاملUsing Gaussian 03, software the thermodynamic functions such as Gibbs free energy, G, Enthalpy, H, and Entropy, S, of Alanine and Valine amino acids were theoretically studied at different solvents. First, the Density Functional Theory (B3LYP) level with 3-21G, 6-31G and 6-31+G basis sets were employed to optimization of isolated Alanine and Valine amino acids in the gas phase. Moreover, Vibrational frequencies were calculated in gas phase on the optimized geometries at the same level of theory to obtain the thermodynamic functions such as Gibbs free energy, G, Enthalpy, H, and Entropy, S,. Then, the calculation about the solvent effects on the thermodynamic functions of Alanine and Valine amino acids were performed for the various solvents (Water, Methanol and Ethanol) by using self consistent Reaction-Field (SCRF=PCM) model at B3LYP/6-31+G. Thermodynamically analysis shows the relative Gibbs free energy changes, G, Enthalpy changes, H, are negative values but the Entropy changes, S, are positive values for Alanine and Valine amino acids. Also, the results shows, with increasing of dielectric constant of solvents the stability of considered amino acids increases. پرونده مقاله -
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3 - Computational Design and Synthesis of Molecular Imprinted Polymers for solid-phase Extraction of Acyclovir
gholamali haghdoostHighly selective molecularly imprinted polymers (MIPs) for solid-phase extraction of acyclovir have been designed and prepared. In order to study the intermolecular interactions in the pre-polymerization mixture and to find a suitable functional monomer in MIP preparati چکیده کاملHighly selective molecularly imprinted polymers (MIPs) for solid-phase extraction of acyclovir have been designed and prepared. In order to study the intermolecular interactions in the pre-polymerization mixture and to find a suitable functional monomer in MIP preparation, a computational approach was developed. It was based on the comparison of the binding energy of the complexes between the template and functional monomers. The effect of the polymerization solvent was included using the polarizable continuum model. According to the theoretical calculation results, the MIP with acyclovir as template was prepared by precipitation polymerization method using acrylamide (AAM) as functional monomer and ethylene glycol dimethacrylate (EGDMA), as cross-linker in acetone. Having confirmed the results of computational method, three MIPs were synthesized with different functional monomers, i.e. acrylamide (AAM), allylamine (AA) and acrylonitrile (ACN), and then evaluated using LangmuirFreundlich (LF) isotherm. The results of this study have indicated the possibility of using computer aided design for rational selection of functional monomers and solvents capable of removal of acyclovir from contaminated fluids. پرونده مقاله -
دسترسی آزاد مقاله
4 - A Theoretical Study of the Stability and Dielectric Constants of Molybdate-Phosphonic Acid Complex
M.H. Ghorbani R. Fazaeli A. GhoorchianIn this work, we investigated the stability of Molybdate-Phosphonic Acid (MPA) complex by density functionaltheory (DFT) computations in six solvents with the dielectric constant ranging from 1.92 to 10.36. The methodsare used for calculations are B3LYP and B3PW9 I that چکیده کاملIn this work, we investigated the stability of Molybdate-Phosphonic Acid (MPA) complex by density functionaltheory (DFT) computations in six solvents with the dielectric constant ranging from 1.92 to 10.36. The methodsare used for calculations are B3LYP and B3PW9 I that have been studied in two series of basis sets: D95nand6-31+G (d,p) for hydrogen and oxygen atoms; LANL2DZ for Mo and Phosphorus. Considering the effect ofsolvent, using PCM solvent model, the stability of MPA complex when passing to higher dielectric constants iscalculated. Predicted geometry and relative stability are discussed. Equilibrium geometry in the groundelectronic state energy has been calculated for 1:1 complex. The best results for energetic and geometricalground state in different of used solvents were obtained with Becke3LYP calculations. An increasingstabilization of MPA when increasing the dielectric constant in a continuum solvent model. پرونده مقاله -
دسترسی آزاد مقاله
5 - Solvent Effect Study on the Stability Energies of Glycine, Alanine and Valine Amino Acides
F. Keshavarz Rezaei A. Taherpour M. AghaieGlycine, Alanine and Valine are taken as amino acids with an equal polar head and with thedifference in the length of hydrocarbon chains. The structural optimizations show the results of theisolated Glycine, Alanine and Valine in the gases phase, at the Hartree-Fock lev چکیده کاملGlycine, Alanine and Valine are taken as amino acids with an equal polar head and with thedifference in the length of hydrocarbon chains. The structural optimizations show the results of theisolated Glycine, Alanine and Valine in the gases phase, at the Hartree-Fock level by means ofSTO-3G,3-21G, 6-31G and 6-31+G basis sets. The calculations were performed for the ten (1-10)solvents using PCM model method at HT/6-31+G and then the dielectric effects of the surroundingwere analyzed. The solvent effect on the stability of Glycine, Alanine and valine molecules wasdiscussed. پرونده مقاله -
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6 - Prediction of accurate pKa values of some α-substituted carboxylic acids with low cost of computational methods
M. Abul Kashem Liton Sabrina Helen Mukta Das Dipa Islam M. Rabiul KarimThe acidity constants (pKa) of thirty four (34) ;-substituted carboxylic acids in aqueous solution havebeen calculated using conductor-like polarizable continuum (C-PCM) solvation model. The gasphaseenergies at the Density Functional Theory (DFT-MPW1PW91) and solvation چکیده کاملThe acidity constants (pKa) of thirty four (34) ;-substituted carboxylic acids in aqueous solution havebeen calculated using conductor-like polarizable continuum (C-PCM) solvation model. The gasphaseenergies at the Density Functional Theory (DFT-MPW1PW91) and solvation energies atHartree Fock (HF) are combined to estimate the pKa values which are very close to the experimentalvalues where, and the root-mean-square error (rmse) is less than 0.9. In addition, the pKa valuespredicted by Multilinear Regression (MLR), Principle Components Regression (PCR) and PartialLeast Square Regression (PLSR) methods showed an excellent correlation to the experimental valueswhere the root-mean-square error (rmse) decreases from 0.9 to 0.293, 0.326 and 0.319 respectively.Furthermore, the rmse of pKa values found less than 0.3 when the solvation models of some powerfulelectron withdrawing substituted acids are employed at the level of MPW1PW91 theory. Thecomputation by different regression methods showed reasonably a better calculation of pKa valuesthrough the lower root-mean-square errors (rmse). پرونده مقاله -
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7 - Theoretical Study of the Solvent Effect on the Stability Energies of Pyrazole and Pyrazoline
Farideh Keshavarz RezaeiUsing the Density Functional Theory (DFT) level by means of 3-21G, 6-31G and 6-31+G (d) basissets, the structural optimization of isolated Pyrazole and Pyrazoline was done in the gas phase. Then,the calculation about the solvent effect on the stability energies of Pyraz چکیده کاملUsing the Density Functional Theory (DFT) level by means of 3-21G, 6-31G and 6-31+G (d) basissets, the structural optimization of isolated Pyrazole and Pyrazoline was done in the gas phase. Then,the calculation about the solvent effect on the stability energies of Pyrazole and Pyrazoline wasperformed for the ten solvents using PCM model method at B3LYP/6-31+G(d) and then the dielectriceffects of the surrounding and the solvent effects on the stability energies of Pyrazole and Pyrazolinemolecules were discussed. پرونده مقاله -
دسترسی آزاد مقاله
8 - The Effect of Type and Location of a Phase Change Material (PCM) Layer in a Building Wall on Energy Consumption using Numerical Simulation
Arezoo Soleimani Dashtaki Afshin Ahmadi Nadooshan Afshin AbediPhase Change Materials (PCMs) have been the subject of many researches in recent years due to the storage and release of energy at low temperature ranges. PCMs store or releasing a large amount of energy at a constant temperature range leads to saving energy. In this pa چکیده کاملPhase Change Materials (PCMs) have been the subject of many researches in recent years due to the storage and release of energy at low temperature ranges. PCMs store or releasing a large amount of energy at a constant temperature range leads to saving energy. In this paper, the numerical modelling of a multilayer composite wall including PCM located on the southern side of a building is carried out using an implicit method. The data correspond the fifteenth day of each month in Tehran. The governing equations are discretized by the implicit Crank Nicolson method and solved by iteration method using MATLAB software. Finally, the location and volume fraction of PCM in the wall of the building are studied to achieve maximum efficiency. The results show that the effect of latent and sensible heat results in a reduction in the input heat flux and thermal load to the building. The optimum location for the PCM layer is the middle layer of the composite wall to reduce the heat transfer rate inside the building. In addition, it is found that the PCM volume fraction in gypsum does not have a significant effect on the thermal performance of the multi-layer composite wall. Hence, low volume fraction reduces the costs without affecting the thermal performance of the building. پرونده مقاله -
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9 - Designing a People Capability Maturity Model Among Faculty Members (Case study: Islamic Azad University of Fars Province
maryam mahdavi nader sheikh al-Islami narges hasanmoradi Narjes ShokriPeople capability maturity model (PCMM) is a framework to help develop the level of maturity and improve the field of human resources of organizations. The present study is conducted with the aim of designing and validating an indigenous PCMM for managers among faculty چکیده کاملPeople capability maturity model (PCMM) is a framework to help develop the level of maturity and improve the field of human resources of organizations. The present study is conducted with the aim of designing and validating an indigenous PCMM for managers among faculty members of the Islamic Azad University of Fars Province. First, the initial indicators are extracted through literature review, then the interview questions are designed and approved by 3 experts. After that, semi-structured interviews are conducted with 17 faculty members who, in addition to having executive records over 5 years, also are assistant professors and above. The sampling method is purposeful snowball. Data analysis is done based on Strauss and Corbin grounded theory model in 6 paradigms of causal conditions, main phenomenon, intervening conditions, context, strategies and consequences. The results of data analysis obtained during 3 open, axial and selective coding processes lead to the extraction of 29 indicators and 98 components. Then, using the obtained variables, a questionnaire is designed and distributed among faculty members, and data are collected and indicators are ranked using confirmatory factor analysis, based on which an indigenous model is presented. Validity and fitting of the model is measured through structural equations using PLS software. The results of validation show that the model has a high validity. According to the discussions and conclusions, one of the research suggestions in increasing the maturity and capability of faculty members can be holding perpetual training courses for managers, which should be implemented by teachers who have a brilliant record in human resource management. پرونده مقاله -
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10 - تحلیل عددی همرفت طبیعی نانوسیال در یک گردآورنده خورشیدی تحت خلا همراه با مواد تغییر فاز دهنده
سید علیرضا ناظم ایمان زحمتکشانرژی خورشیدی به عنوان یک منبع انرژی ابدی و گسترده، چگالی پایینی دارد و شدت آن به طور پیوسته در حال تغییر است. عدم دسترسی به انرژی خورشیدی در شب و شکاف بین زمان تابش و مصرف آن، نقاط ضعف اصلی آن به شمار می روند. در کاربردهایی از قبیل آبگرم مصرفی (DHW)، مواد تغییر فاز دهن چکیده کاملانرژی خورشیدی به عنوان یک منبع انرژی ابدی و گسترده، چگالی پایینی دارد و شدت آن به طور پیوسته در حال تغییر است. عدم دسترسی به انرژی خورشیدی در شب و شکاف بین زمان تابش و مصرف آن، نقاط ضعف اصلی آن به شمار می روند. در کاربردهایی از قبیل آبگرم مصرفی (DHW)، مواد تغییر فاز دهنده (PCM)، با ظرفیت گرمایی بالا و دمای ثابت در طول فرآیند تغییر فاز می توانند این چالش مهم را برطرف سازند. با این وجود، کوچک بودن ضریب رسانش گرمای آب، عملکرد گردآورنده خورشیدی لوله خلا را کم می کند. البته با به کارگیری نانوسیالات می توان رسانش گرمای آب را به میزان چشمگیری افزایش داد. این مقاله به تحلیل عددی همرفت طبیعی نانوسیال در یک گردآورنده خورشیدی تحت خلا همراه با مواد تغییر فاز دهنده می پردازد. نانوذرات بررسی شده شامل اکسید مس، اکسید تیتانیوم، اکسید آهن، اکسید آلومینیوم و اکسید گرافن می باشند. نتایج به دست آمده نشان می دهند که به ازای همه نانوذرات بررسی شده، با افزایش کسر حجمی نانوذرات، مقدار دمای خروجی از گردآورنده کاهش می یابد. مشخص می شود که بیشترین دما در هنگام استفاده از نانوذرات اکسید گرافن رخ می دهد. پرونده مقاله -
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11 - Production, Characterization and Application of Nano - Phase Change Materials: A Review
Pouriya Norooz Kermanshahi Graça SoaresPhase Change Materials (PCMs) for heat storage and energy saving has been extensively used in many fields for heating and cooling processes, including building, solar energy, textiles, agriculture, and electronics. PCMs have been getting incredible attention for being l چکیده کاملPhase Change Materials (PCMs) for heat storage and energy saving has been extensively used in many fields for heating and cooling processes, including building, solar energy, textiles, agriculture, and electronics. PCMs have been getting incredible attention for being low-cost materials and have potential materials for thermal energy storage (TES) with long cycle life. Though, the disadvantages such as flow, result in encapsulation in three scales of Macro, Micro and Nano capsules. Encapsulating PCM reduces the disadvantages and improves the efficiency of PCMs. Different methods for producing PCMs in the scale of nano and core-shell materials, have been developed and the capsules size in relation to parameters such as pH, stirring rate, material selection and preparation method have been investigated. In recent years, this subject has been extensively studied, seeking to find more efficient and safer PCMs. In this context, nanoscale PCMs have been produced and applied to the most diverse products and their performance evaluated. They simply modified and optimized production processes. The novelty of this study lies in the fact that merely a few articles have reviewed nano-encapsulating of PCMs, focusing on new developments on PCM nano-capsules. Moreover, few articles have compared nano and microcapsules of PCMs so far. The analyzed papers suggest that the production methods influence the size of the obtained capsules. The purpose of this article is to make an updated review of the synthesis and application of nano-encapsulated PCMs. پرونده مقاله -
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12 - تحلیل تجربی و عددی تاثیر سایز و محل دریچه های دیوار ترومب با استفاده از مواد تغییر فاز دهنده (PCM)
عبدالله خالصی دوست محمدامین خانی احد عابدینی اسفهلانیاز آنجاییکه بیش از یک سوم انرژی مصرفی دنیا در بخش ساختمان میباشد، ساختمان سبز و معماری پایدار تکنیک‌های جدیدی برای مقابله با بحران محیط زیست و کاهش مصرف انرژی در ساختمانها می باشند. استفاده از دیوار ترومب در ساختمانهای مسکونی، اداری و تجاری باعث کاهش مصرف انرژی گردیده و چکیده کاملاز آنجاییکه بیش از یک سوم انرژی مصرفی دنیا در بخش ساختمان میباشد، ساختمان سبز و معماری پایدار تکنیک‌های جدیدی برای مقابله با بحران محیط زیست و کاهش مصرف انرژی در ساختمانها می باشند. استفاده از دیوار ترومب در ساختمانهای مسکونی، اداری و تجاری باعث کاهش مصرف انرژی گردیده و ذخیره انرژی خورشیدی توسط مواد تغییر فاز دهنده نیز اثر کار را دو چندان مینماید و این امر باعث تغییر رویکرد طراحی ساختمانها به سمت ساختمان سبز و نهایتا محیط زیست با آلودگی کمتر خواهد شد. به همین منظور در این تحقیق به بررسی کنوکسیون طبیعی در دیوار ترومب با مواد تغییر فاز دهنده و تاثیرسایز و محل نصب دریچه های ورودی و خروجی هوای ورودی بر عملکرد دیوار مذکور پرداخته شده است. پژوهش مذکور بصورت تجربی و عددی صورت گرفته است.پس از ساخت دیوار ترومب با مواد تغییر فاز دهنده و جمع اوری داده های تجربی، شرایط فیزیکی حاکم بر مسئله در نرم افزار فلوئنت شبیه سازی شده وسپس نتایج آزمایشگاهی با حل عددی مقایسه شده است. نتایج تحقیق نشان میدهد تغییر سایز دریچه ها باعث افزایش 16 درصدی درجه حرارت خروجی دیوار ترومب گردیده و تغییر محل دریچه ها در راستای افقی تاثیر چندانی درافزایش دمای خروجی ندارد. اختلاف 2 درصدی نتایج حل عددی با داده های تجربی بیانگر دقت کار و تحلیل مسئله می باشد. پرونده مقاله -
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13 - Solvent influence on the interaction of cis-PtCl2(NH3)2 complex and graphene: A theoretical study
Reza Fazaeli E Ebrahimi Mokarram H Aghaei K Zare Mohammad YousefiIn this investigation the interaction of cis-PtCl2(NH3)2 complex and graphene were investigated with MPW1PW91 method in gas and solvent phases. The solvent effect were examined by the self-consistent reaction field theory (SCRF) based on Polarizable Continuum Model (PCM چکیده کاملIn this investigation the interaction of cis-PtCl2(NH3)2 complex and graphene were investigated with MPW1PW91 method in gas and solvent phases. The solvent effect were examined by the self-consistent reaction field theory (SCRF) based on Polarizable Continuum Model (PCM). The selected solvents were chloroform, chlorobenzene, bromoethane, dimethyldisulfide, and dichloroethane. The solvent effect on the frontier orbital energy and HOMO-LUMO gap were studied. Negative value solvation energy of the between cis-Pt(NH3)2Cl2 …. graphene complex signifies the more stability of the complex in solution in compared to gas phase.The characterization of the interaction between two fragments was clarified with energy decomposition analysis (EDA). Pt-C(Graphene) and H(NH3)...C(Garaphen) interactions in the graphene … cis-PtCl2(NH3)2 complex were analyzed using quantum theory of atoms in molecules analysis (QTAIM). cis-Pt(NH3)2Cl2 and graphene fragments contribute in HOMO and LUMO of complex, respectively.In the basis of QTAIM analysis, the characteristics of the Pt…C(Graphene) and H(NH3)… C(Graphene) interactions was intermediate between closed-shell and shared interactions.EDA and structural parameters predict stronger interaction between cis-Pt(NH3)2Cl2 and graphene in gas phase. پرونده مقاله -
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14 - Solvent influence on the interaction of cis-PtCl2(NH3)2 complex and graphene: A theoretical study
Elham Ebrahimi Mokarram Reza Fazaeli Hossein Aghaei Mohammad Yousefi Karim ZareIn this study the interaction of cis-PtCl2(NH3)2 complex and graphene were investigated with MPW1PW91method in gas and solvent phases. The solvent effect was examined by the self-consistent reaction fieldtheory (SCRF) based on Polarizable Continuum Model (PCM). The sele چکیده کاملIn this study the interaction of cis-PtCl2(NH3)2 complex and graphene were investigated with MPW1PW91method in gas and solvent phases. The solvent effect was examined by the self-consistent reaction fieldtheory (SCRF) based on Polarizable Continuum Model (PCM). The selected solvents were chloroform,chlorobenzene, bromoethane, dimethyldisulfide, and dichloroethane. The solvent effect on thefrontier orbital energy and HOMO-LUMO gap were studied. The characterization of the interactionbetween two fragments was clarified with energy decomposition analysis (EDA). Pt-C(Graphene) andH(NH3)...C(Garaphen) interactions in the graphene … cis-PtCl2(NH3)2 complex were analyzed usingquantum theory of atoms in molecules analysis (QTAIM). پرونده مقاله -
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15 - A Review on the Photovoltaic Panels: Applications, Modeling and Economic Evaluation with Focusing on the Phase Change Material Cooling Method
Seyyed Masoud SeyyediA photovoltaic (PV) panel consists of several photovoltaic cells designed to convert solar radiation into electrical energy. Cooling of PV cells is an important task to increase PV panel efficiency, improve output power and optimize performance parameters. There are var چکیده کاملA photovoltaic (PV) panel consists of several photovoltaic cells designed to convert solar radiation into electrical energy. Cooling of PV cells is an important task to increase PV panel efficiency, improve output power and optimize performance parameters. There are various methods for PV cooling. Phase change materials (PCMs) can be used to cool PV panels. The integrated system is called PV-PCM system. This paper provides an overview of the history, applications, mathematical modeling and economic evaluation for PV-PCM systems. The focus of this study is on the cooling of the PV cells using PCMs. Furthermore, the other types of PV systems (hybrid systems) are investigated. The effects of main parameters on the performance of PV or PV-PCM systems are investigated, too. Mathematical modeling including thermal and electrical models are presented. Finally, the advantages and disadvantages of PV-PCM system and its future overview are discussed. The results discover that the PV panel temperature up to 20 °C and electrical efficiency up to 5% can be reduced by PCM.. The results discover that the PV panel temperature up to 20 °C and electrical efficiency up to 5% can be reduced by PCM. پرونده مقاله -
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16 - Solvent Effects on Medicinal Structure and 15N NMR Shielding of Medazepam
Arezoo Tahan Fatemeh AlimohammadiThe Density Functional Theory (DFT) and Tomasi’s Polarized Continuum Model (PCM) were used to investigate the effects of solvent dielectric constant on the structural stability and 15N NMR tensors of Medazepam (MDZ) drug. The results revealed that the structural s چکیده کاملThe Density Functional Theory (DFT) and Tomasi’s Polarized Continuum Model (PCM) were used to investigate the effects of solvent dielectric constant on the structural stability and 15N NMR tensors of Medazepam (MDZ) drug. The results revealed that the structural stability of MDZ in polar protic solvents was higher than that in the polar aprotic and non-polar solvents; and its value depended on the solvent dielectric constant and its structure. so that in most cases, relative stability increased by increasing the solvent dielectric constant and the most stable structures were observed in water media at DFT level and in methanol at MP2 level. In this regard, natural bond orbital (NBO) interpretation showed that the tetravalent N1 nucleus of diazepine ring in the MDZ structure had the highest value of negative charge and the resonance energy related to LP (1) N1 → σ* and π* delocalizations among heteroatoms of MDZ structure in the tested solvents. The findings reported that with an increase in the solvent dielectric constant, the resonance energy related to LP (1) N1 → σ* and π* delocalizations increased and the highest value of resonance energy was observed in water media. Furthermore, NMR results represented that the N1 nucleus had a higher value of chemical shielding than the trivalent N4 nucleus in all of the tested media. However, it may be concluded that by increasing the accumulation of negative charge and lone pair electrons participation of nitrogen nuclei in the resonance delocalizations, isotropic chemical shielding around them increase. پرونده مقاله -
دسترسی آزاد مقاله
17 - Investigating the use of PCM on the performance of solar water heaters in cloudy and sunny weather by using nanoparticles in their structure to reduce energy consumption in buildings
Saeed Samadzadeh Baghbani Farivar Fazelpour Hossein Ahmadi Danesh AshtianiPhase change materials in the structure of buildings reduce energy consumption and increase the storage of renewable energies .In this study, in order to investigate the effect of phase change materials on the performance of a solar collector in unstable weather conditi چکیده کاملPhase change materials in the structure of buildings reduce energy consumption and increase the storage of renewable energies .In this study, in order to investigate the effect of phase change materials on the performance of a solar collector in unstable weather conditions (cloudy weather) in Tehran, numerical simulation of the collector was carried out using Ansys Fluent software. For this purpose, four scenarios were examined and numerically simulated. In the first scenario, the performance of the solar collector was investigated in the stable weather conditions of Tehran city without the use of phase change material. The results showed that the desired solar collector can raise the water temperature to 38 degrees Celsius. In the second scenario, to investigate the effect of air instability and cloudiness on the performance of the collector, it was assumed that the solar radiation will decrease. The results showed that the temperature of the outlet water of the collector decreases from 38 degrees Celsius to 35 degrees with the reduction of sunlight. In the third scenario, the effect of using phase change materials on the performance of the collector in stable weather conditions was investigated. The results showed that the use of phase change material in the collector causes heat storage and increases the water temperature when the solar radiation decreases to 37 degrees Celsius. Also, the use of phase change materials in unstable weather conditions caused the water temperature to increase to 41 degrees Celsius. پرونده مقاله -
دسترسی آزاد مقاله
18 - Heat transfer Simulation of solar wall phase chang materials (PCM) for energy storage and optimization
Ali Akbar Hosseinjaniphase change materials have a high capacity in thermal energy storage, these materials can be used to prevent the heat transfer into the building besides optimize and improve the performance of the refrigeration and air conditioning system. Adding phase change materials چکیده کاملphase change materials have a high capacity in thermal energy storage, these materials can be used to prevent the heat transfer into the building besides optimize and improve the performance of the refrigeration and air conditioning system. Adding phase change materials (PCM) to the building can improve the inside comfort temperature and save consumption energy of the building. In this article the parameters that affect the performance of PCM in the building walls, such as phase change temperature, latent heat, thickness, thermal conductivity, etc., have been investigated using ANSYS software. the numerical simulation of thermal energy storage in the solar walls of the building have investigated using phase change materials in different thicknesses with different heat flux rates. This wall is designed to capture the sun energy during the day, reducing energy consumption and optimizing it during peak times. پرونده مقاله
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