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Modeling the Solar Heat Pump with an Energy Storage System
, M.Sc. Thesis Sharif University of Technology ; Samimi , Jalal (Supervisor) ; Vesaghi, Mohammad Ali (Supervisor)
Abstract
Purpose of ongoing thesis is providing a tool for suitable modeling, increase efficiency and decrease construction cost of solar absorption heat pump. At first, the solar absorption heat pump is modeled by the thermodynamic laws. Then, this model is converted to the new standard mathematical programming model using exergy and thermodynamic Analysis with considering all technical and economic constrains. This mathematical model is optimized by Genetic algorithm (GA). Because of the nonlinear objective function and the constraint, GA is used as optimization algorithm. After applying GA, optimized parameters of cycle heat exchanger designing and its electricity consumption are calculated....
Study of the Effects of Mass Fraction and Flow Velocity Fluctuations on Diffusion Flame
, M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad (Supervisor)
Abstract
In this work, the unsteady response of a laminar diffusion flame to harmonic mass fraction oscillations and also to flow velocity fluctuations is investigated. Flame-sheet assumption is utilized to model the laminar unsteady two-dimensional co-flow diffusion flame mathematically. The initial combustion of most combustion chambers is through diffusion mechanism. Therefore, developing analytical model of diffusion combustion is of great importance. The flow is assumed subsonic (incompressible), inviscid, and uniform. The convection-diffusion equation for conserved scalar variable with appropriate boundary conditions is solved. Considering stoichiometric mass fraction surface to be the flame...
Controlled Microwave-assisted Synthesis of ZnFe2O4 Nanoparticles and Investigation of their Catalytic Activity in Organic Reactions
, M.Sc. Thesis Sharif University of Technology ; Matloubi Moghaddam, Firouz (Supervisor)
Abstract
ZnFe2O4 nanoparticles have been successfully prepared through a controlled microwave–assisted co-precipitation as well as conventional co-precipitation. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were used for the structural, morphological and magnetic investigation of the product. Average particle size was obtained as 12 nm from XRD. Catalytic activity of ZnFe2O4 nanopowder for O-acylation of alcohol and phenol has been investigated. A trace amount of ZnFe2O4 has been effectively used as a nanocatalyst for the acylation of alcohol and phenol in acetic anhydride.
Numerical Simulation of Nano-Impinging-Jet in Electronic Cooling Applications
, M.Sc. Thesis Sharif University of Technology ; Darbandi, Masoud (Supervisor)
Abstract
With a fast progress in nanotechnology devices and components, e.g., MEMS/NEMS, heat transfer study in micro/nanoscales has become so critical for the systematic design and precise control of such miniaturized devices towards the integration and automation of Lab-on-a-chip devices. Demands in high heat transfer rates have returned the concerns to impinging jet cooling systems. However, studying impinging jets in the micro/nano scales is requires the molecular dynamics knowledge to analyze the true micro/nanoscale flow behavior accurately. According to the importance of this subject, we use direct simulation Monte Carlo (DSMC) method to simulate nano impinging jet gas flows. The thesis is...
Thermal Modeling of a Typical Room by Use of Inverse Analysis
,
M.Sc. Thesis
Sharif University of Technology
;
Kazemzadeh Hannani , Siamak
(Supervisor)
;
Taghizadeh Manzari, Mehrdad
(Supervisor)
Abstract
Building simple and effective models are essential to many applications, such as building performance diagnosis and optimal control. Detailed physical models are time consuming and often not cost-effective. Black box models require large amount of training data and may not always reflect the physical behaviors. In this study, a method is proposed to simplify the building thermal model and to identify the parameters of the simplified model. For instance, predicting the next-24-hour load in a building is essential for the optimal control of heating, ventilating and air-conditioning (HVAC) systems that use thermal or cool storage technology. In the first phase of this study, equations for...
Experimental of Convective Heat Transfer Coefficient Around a Vertical Rod Bundle
, M.Sc. Thesis Sharif University of Technology ; Jafari, Jalil (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
Abstract
Research on convective heat transfer coefficient around a rod bundle has several applications in industry. So far, many studies have been conducted in correlations related to internal fully developed flow. By comparing Dittus-Boelter, Sieder-Tate and Petukhov found to be more practical. The present study examines the validity of these frequently applied correlations experimentally. A thermohydraulic loop has been designed and manufactured to test and measuring the convective heat transfer coefficient. Due to its generalizibility, the unique geometry of this test facility (hexagonal arranged, 7 vertical rods in a hexagonal tube) has achieved extensive application. The major deviation factors...
Modeling and Optimization of Solar Cooler for Domestic Usage
, M.Sc. Thesis Sharif University of Technology ; Roshandel, Ramin (Supervisor)
Abstract
In this thesis a general model for simulation of solar cooler for domestic usage is developed. The model consists of 2 main parts: thermo-dynamical and economical calculations. The thermodynamic part consists of 4 sub models: a model for calculation of incoming solar radiation, cooling load demand calculation, the refrigeration cycle and the solar cycle with heat storage.As for hourly calculation of system performance part of the model produces the hourly received radiation data based on geographical position and orientation of the receiving surface. Base on results of the cooling load calculation for a 9 m2 studying room located in western part of Tehran, 1 TBR (3.516 kW) is chosen as...
In this thesis a general model for simulation of solar cooler for domestic usage is developed. The model consists of 2 main parts: thermo-dynamical and economical calculations. The thermodynamic part consists of 4 sub models: a model for calculation of incoming solar radiation, cooling load demand calculation, the refrigeration cycle and the solar cycle with heat storage.As for hourly calculation of system performance part of the model produces the hourly received radiation data based on geographical position and orientation of the receiving surface. Base on results of the cooling load calculation for a 9 m2 studying room located in western part of Tehran, 1 TBR (3.516 kW) is chosen as...
Prediction of Homogeneos Charge Compression Ignition (HCCI) Engines Performance Using Multi-Zone Model
, M.Sc. Thesis Sharif University of Technology ; Mozafari, Ali Asghar (Supervisor)
Abstract
Some researches have been carried out in the last 20 years in order to increase the present IC engines thermal efficiency and their optimum performance. (HCCI) engine is viewed as a combination of spark-ignition (SI) and compression-ignition (CI) engines. This is because HCCI engines use premixed fuel/air mixture like SI engines and have auto ignition combustion after the mixture is compressed like CI engines. Control of combustion and ignition timing are the main challenges of these engines. Ignition delay, compression ratio, fuel air equivalence ratio and intake temperature and pressure are considered to be the most effective parameters on HCCI combustion.HCCI engines have great potentials...
Thermal-economic Modeling and Optimization of Ground-Coupled Heat Pump System for Various Climatic Conditions of Iran
, M.Sc. Thesis Sharif University of Technology ; Abbaspour Tehrani Fard, Madjid (Supervisor)
Abstract
The optimal design of a ground-coupled heat pump (GCHP) system with vertical ground heat exchanger (VGHX) includes thermal modeling of the system and selection of optimal design parameters is presented in this research. Then, by applying Nelder-Mead optimization algorithm, an objective function (Total Annual Cost which is the sum of annual investment and operating costs of the system) is defined and minimized, exposed to specified design constraints. Also, Genetic Algorithm is used to verify the optimal design process. In order to evaluate the accuracy of a presented model, the optimum values of a heat pump design parameters includes saturated temperature/pressure of a condenser and...
Numerical and Experimental Investigation of Thermally Driven Exchange Flow and Wind set up in Canopy Steep Area
, M.Sc. Thesis Sharif University of Technology ; Jamali, Mirmosaddegh (Supervisor)
Abstract
Solar heating in aqautic systems, causes tempreture increasing.This temperature difference will promote an exchange flow between the vegetation and open water. The exchange flow generated by the differential heating and cooling associated with depth variation has also been studied through laboratory experiment and modelling. Differential solar heating can result from shading by rooted emergent aquatic plants, producing a temperature difference between vegetated and unvegetated regions of a surface water body. Horizontal density difference between shaded and open water regions drives currents that carry fluxes between biologically and chemically distinct regions of an aquatic system. Such...
Modeling, Analysis and Possible Solution for Excessive Intraocular Pressure in Glaucoma Patients
, M.Sc. Thesis Sharif University of Technology ; Firouzbakhsh, Keykhosrow (Supervisor)
Abstract
With the advent of new computer technologies, computational analysis on the human organs has become tremendously popular in the field of medical science. Every year thousands of people suffer irreversible eye damages pertaining to lack of adequate medications. In this regards, enormous amount of money is spent annually but mostly in vain due to the irreversibility and silent nature of eye diseases like glaucoma. Yet more precise studies on the topic are requisite. In this thesis, a validated half 3D finite volume model of human eye considering the fluid flow in collaboration with heat transfer in the steady state utilizing the well known discretized bio-heat transfer equation coupled with...
Residual Stress Determination of Multi-pass Welding Process, Stress Relieving Procedures and Its Effect on Crack Propagation
, M.Sc. Thesis Sharif University of Technology ; Farahi, Gholamhossein (Supervisor)
Abstract
One of the most important issues in welding is residual stresses. It is desirable to produce less residual stresses when possible and to reduce them which remain in the structure. At the present, various methods have been developed to reduce the residual stresses. The most important methods are heat treatment, shot peening, and grinding. The main problem in using these methods is cost, and for large structures these methods are often impractical. In recent decades, a technique called vibratory stress relief has been developed. It is used for large structures without limitation of size and weight; besides, the cost of this process is much less in comparison with other conventional methods...
The Experimental Investigation of Rotating Pulsating Heat Pipe
, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad (Supervisor)
Abstract
Developing of electric instruments with high performance needs high capacity heat transfer equipments. Pulsating heat pipes have better performance compared with normal heat pipes and can be used for cooling electronic instruments in near future. Also, one specific kind of heat pipes, which is called rotating pulsating heat pipe, can be used in cooling the turbine blades. Rotating pulsating heat pipe is a mechanism in which the pipes can rotate around the axis perpendicular to the plane of pipes. In this research one rotating heat pipe was built and the effects of heat input, filling ratio and rotational acceleration were examined experimentally. The Innovation in the research was to obtain...
Conduct an Investigation on Nanostructure of Al-20Si-5Fe Alloy, Produced by Melt Spinning Process and Observation of Mechanical-Metallurgical Properties
, M.Sc. Thesis Sharif University of Technology ; Davami, Parviz (Supervisor)
Abstract
In this study, Al-20Si-5Fe ribbons produced by melt-spinning method. Nanostructure and growth morphology of rapidly solidified products explored using optical microscope, scanning electron microscope and x-ray diffraction. Microstructural investigations depicted two distinctive zones of featureless (faceted morphology) and dendritic. In addition, no intermetallic phases could be observed in the rapidly solidified ribbons in comparison with coarsed and needle shaped intermetallic phases of as cast alloys which it demonstrates the extension of solid solubility of Si and Fe in the matrix and consequently intermetallics formation was hindered by higher cooling rates. Subsequently, ribbons...
Technical and Economical Feasibility Study of Applying Heat Pump Systems to Provide Utilities for Oil & Gas Industries
, M.Sc. Thesis Sharif University of Technology ; Sattari, Sorena (Supervisor) ; Amidpour, Majid (Supervisor)
Abstract
Distillation is the most applied unit in the separation processess of the oil and gas industries. Because the distillation process requires energy in the form of the utilities, integration of heat pump systems in the distillation process as an application of these systems is considered in this research. A new and effective methodology of proper integrating of heat pump and distillation columns has been proposed by collecting thermodynamic and thermoeconomic tools. Then, this procedure has been applied on the ethane recovery and NGL fractionation units of 4 & 5 phases of the south pars field. The exergy analysis of the distillation columns is the first step of this methodology as the...
Simulation for Optimized CHP and Piping Network Design for Residential Area
, M.Sc. Thesis Sharif University of Technology ; Abbaspour, Madjid (Supervisor) ; Kazemzadeh, Siamak (Supervisor)
Abstract
Rapid growing use of energy resources in recent decades, caused to focus on combined heat and power generation systems according to their high efficiencies. Energy efficiencies with these technologies will be up to 90 percent. Some benefits of Co-generation systems are their high efficiencies, omitting of transmission and distribution lossesin the electricity grid, fuel consumption reduction, moving to ward privatization,independent and decentralized production of electricity and heat, increase competition in the power generation and reduction theemission of greenhouse gases, particularly carbon dioxide. In This article theeconomicsof combined heat and power generator stobe installed...
Simulation of Air to Air Plate Heat Exchangers to Investigate the Effects of Baffle Location, Header and Fins Geometry in their Performance
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Farhanieh, Bijan (Supervisor)
Abstract
Many studies have been conducted in plate heat exchangers. However, some effective parameters on the performance have been less considered. It has been demonstrated that heat exchanger performance increases with more uniform flow distribution. It is possible to make the flow distribution more uniform by installing a baffle inside the header. The ‘gap’ or the distance between this baffle and the inlet is one of the important parameters in determining performance but is has been mostly overlooked by previous studies. This study investigates the effects of inlet baffle place on heat exchanger performance. Another important factor is the header geometry. Elongation and reduction in header...
Experimental Investigation of the Effect of Nano-Fluid on the Performance of Pulsating Heat Pipe
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor) ; Shafii, Behshad (Supervisor)
Abstract
Improving efficiency of heat exchangers has always been an important concern for the industry. Pulsating Heat Pipes (PHPs) are novel and efficient technology in the field of heat transfer. PHPs are widely used in solar water heaters, solar desalination systems, etc. In this research, thermal performance of Open Loop Pulsating Heat Pipes (OLPHPs) using three different ferrofluids (ferrofluid without surfactant and nanoparticles’ coating, ferrofluid with coating of nanoparticles, and ferrofluid with surfactant) is experimentally investigated. In addition, effects of charging ratio (20, 40, 60, and 80%), heating power (20, 30, 40, 50, 60, 70, 80, 100, 120, 140, 160, 180, 200, 240, 280, 320,...
Optimal Energy and Exergy Model of Waste Heat Recovery Systems in Cement Industry
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor)
Abstract
Nowadays, cement has become the cornerstone of any modern society especially in developing countries. But, cement production process is highly energy intensive and emits significant volumes of carbon dioxide.According to the latest reports, Iranian cement industry accounts for about 14.5% of total industrial sector’s energy consumption and this indicates the importance of sustainable development for cement industry concerning national energy and environmental constraints.Based on these facts, current study assesses the technology improvement opportunities particularly waste heat recovery power generation (WHRPG) technology for Iranian cement industry. This needs identifying optimized mass...
Experimental Investigation on Laminar Forced Convection Heat Transfer of Ferrofluids Under an Alternating Magnetic Field
, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad (Supervisor)
Abstract
This research study presents an experimental investigation on forced convection heat transfer of an aqueous ferrofluid flow passing through a circular copper tube in the presence of an alternating magnetic field. The flow passes through the tube under a uniform heat flux and laminar flow conditions. The primary objective was to intensify the particle migration and disturbance of the boundary layer by utilizing the magnetic field effect on the nanoparticles for more heat transfer enhancement. Complicated convection regimes caused by interactions between magnetic nanoparticles under various conditions were studied. The process of heat transfer was examined with different volume concentrations...