eScholar-UMT
eScholar is the institutional repository for research conducted at UMT and maintains a large collection of theses, dissertations and projects produced by UMT graduates as part of their respective degree programs. It includes (but not limited to):
- PhD/MS Theses
- Graduate Program Research Projects
- Undergraduate Program Reports and Final Year Projects
- Full-text articles/research work of faculty and students
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Photovoltaic panel array configuration optimization to reduce lift force by using CFD and genetic algorithm
(UMT, Lahore, 2021) Asfand Yar Khan
One of the most important aspects while considering a PV plant is its levelized cost of energy production (LCOE). Structures and anchor mechanisms constitute of a significant amount of Capital expenditure. Aerodynamic lift force acting on the solar structure is important while designing the counterweight for roof top mounted solar systems. Moreover, pre-fabricated roofs installed in most industrial facilities and not load bearing and do not allow anchors into the roof. So the counterweight placed on top of these roofs must be reduced to make the rooftop installation viable. Due to their unique configuration, the load estimated for solar structures using international building codes can be either higher or lower than actual. CFD simulations are proven to be an efficient tool for estimation of wind loads on solar panels for design purposes and identification of critical design cases. CFD simulations usually require high computation power and slight changes in geometry to find optimum configuration can be time consuming. This research combines Genetic Algorithm’s with CFD to optimize the solar PV array configurations against the effect of wind. Design parameters considered in this research include are Pitch between two PV panel rows and Tilt angle of each row. Only combinations with above 80% performance ratio were carried forward for fitness assessment. Three different Rooftop PV plant layout configurations are analyzed in this research. Two rows of PV panel arrays are considered for optimization in 2D domain using ANSYS Fluent. Results show that the difference of wind lift force between optimized configuration against that with maximum lift force configuration for all the three cases is above fifty percent
Thermal impact analysis of photovoltaic solar panels on climate change
(UMT, Lahore, 2021) Zulqarnain Riaz
Production of electricity from photovoltaic solar panels has burgeoned in recent years, as the total global capacity reached 306GW in 2016, and still growing with a massive rate of 50% [1, 2]. The development of solar power plant is wide spread across a range of diverse ecosystems and locations, ranging from deserts in California, to forests in England, to tropical regions. Yet the environmental impacts of such facilities have not been comprehensively addressed in the current literature. Solar parks may have consequences for several environmental changes, and the deployment of PV solar panels on a wide scale has faced potential negative environmental implications, yet there has been very little research effort to quantify the impacts on local climate. It is uncertain that whether the PV solar power plants have potential to create heat Island effect or their presence is unnoticeable. The physical presence of solar parks will impact solar radiation fluxes and thus temperature. Prior studies and work on the photovoltaic heat Island effect has been mostly theoretical and their scope is limited to only a single biome. I aimed my scope of study on two crucial parameters of the atmosphere i.e. temperature and humidity, (the humidity is calculated for only site No. 1 as Karachi is a coastal city). The sensors were installed under the solar panel for site 1 and site 2 and over the solar panel for site 3. From the results, I found that the daily minimum and maximum temperatures were significantly warmer and cooler respectively, when compared with the result of reference point without solar panels. The rise in the temperature at night was found at all three (03) sites, which shows that the solar panels acts as black body and absorbs solar radiations at day time and release the same at night creating the PV heat island effect. Hence it is concluded, the deployment of PV solar plants alters the process of reflection of the incoming solar energy into the atmosphere. PV solar plants reduce albedo due to which landscape becomes darker and less reflective. Photovoltaic renewable energy has given rise to the concerns about the engendered rise of heat Island effect.
Fixture layout and clamping force optimization for sheet metals
(UMT, Lahore, 2020) Adeel Qadir
Elastic deformation produced during machining effects the dimensional and form errors of workpiece. For precision, accuracy, fine surface finish and minimized workpiece elastic deformation; the parameters like number and position of fixture elements and clamping forces are optimized. The work on rigid bodies is well established but the work on sheet metals is still under process by various researchers due to flexible nature of the sheet metals. The objective of this research work is to optimize the number and position of the clamps and also to optimize clamping forces to keep the maximum deformation of individual nodes up to 2 mm by minimizing the total deformation normal to the plane of workpiece. N-3-2-1 fixturing principle is used to place clamps on sheet metals. The value of N≥1. Fixturing principle provides constraints on 6 Degree of freedom of workpiece and stability to workpiece which increases the machining and assembly accuracy of workpiece. In this research, design elements are the clamps of primary plane whereas locators in secondary and tertiary planes are kept non design elements. To maximize the machining area, clamps are placed only at edges of workpiece. Selection of clamps depends totally on experience of designer. Automatic selection of number and position of clamps is new. In this research, a method is proposed to select number and position of clamps for sheet metals automatically. This work consists of two stages; stage 1 and stage 2. In stage 1; optimized number and position of clamps are calculated by Response Surface Methodology (RSM). It is done by considering initial number and position of clamps from already published work. In stage 2, clamping forces are calculated for optimum layouts obtained by RSM. Stage 1 involves a structural optimization technique; Response Surface Methodology. In RSM, a relationship between set design variables; number and position of clamps and an optimal response; deformation gives an approximation model using Minitab. The second order mathematical model is developed for workpiece elastic deformation. As the predictive model is being developed by response surface methodology, a huge reduction in computational complexity and time is achieved during the optimization of number and position of clamps. The necessary data for building the response models are generally collected by the design of experiments. In this work, the collection of experimental data adopts a standard RSM design, central composite design (CCD) and the approximation of response is proposed using the fitted second-order polynomial regression model known as quadratic model. Maximum deformation for each optimized layout was kept up to 2 mm.
In 2nd stage, Clamping forces are calculated for optimum layouts obtained in stage 1. To calculate the minimum clamping forces to hold the workpiece, friction forces are considered due to clamps. A method; Balancing force moment is used for calculations of clamping forces. It states; Equilibrium occurs when the sum of all forces in the x, y and z direction is zero and the sum of moments at any point is zero. Coulomb static friction law is used to verify the calculated clamping forces required to hold the workpiece. The forces in each direction are multiplied by the static friction coefficient value. It gives the friction force values due to the clamps. For equilibrium condition, the amount of friction force should be greater than or equal to the machining force in that direction. Clamping forces are calculated for optimum layouts while keeping maximum deformation up to 2 mm. Two case studies are used; flat plate and spacer grid. Different loads at different positions are applied to check the effectiveness of proposed methods. After determining the geometric center, workpiece geometry is divided in to 4 hypothetical quadrants. Quadrants with minimal deformation are considered as non-design quadrants. Quadrants with maximum deformations are considered as design quadrants. Clamps are mounted in two different ways with in the proposed method. When clamps are mounted on long edge of workpiece, the condition is called 1 design edge. When clamps are mounted on both short and long edges of the workpiece, it is called 2 design edges. Both case studies are divided into subcases. For case study 1; subcase 1, subcase 2, subcase 3, subcase 4, subcase 5, subcase 6, subcase 7 and subcase 8 are considered. For all subcases, optimized number of clamps is 4, but for subcase 1; optimized number of clamps is 5 in number. For case study 2; subcase 9, subcase 10, subcase 11 and subcase 12 are used. For all subcases optimized number of clamps is 4.
Experimental setup is also designed to check the effectiveness of proposed methods. Simulation results obtained for case study 1 only are verified. The final experimental results fully justify the computational results. Maximum deformation for all subcases is less than 10%. Several factors like analogue dial indicator, human errors are the reason of difference in values.
Energy conservation and optimization of HVAC design in-line with USGBC codes
(UMT, Lahore, 2020) ARSLAN FAISAL
With the rapid growth in global population and continuous improvement in the quality of life style, the energy consumption is at rise causing an increase in fossil combustion and ultimately pollution. Therefore, efforts are being made to optimize energy consuming systems for power utilization. In large buildings, small electrical air conditioners are not used due to their high power consumption and short running life, but preference is given to the central air conditioning for being more economical due to its lower maintenance cost and being energy efficient. Therefore, in large buildings such as auditorium, educational and commercial buildings, central air conditioning systems are used. The precise calculation of cooling load is needed to reduce capital cost and power consumption, and to maintain a comfortable environment in a building.
This research work presents cooling load calculation for a building in the University of Management and Technology (UMT), Lahore, Pakistan for peak running time using cooling load temperature difference (CLTD) method. Sensible cooling load calculation for vapor compression system using CLTD method is presented to replace the existing high-power consumption cooling system, partially or completely, with an energy efficient system for maintaining human comfort without effecting indoor air quality (IAQ). The heat gains due to structure, lighting, occupancy, and equipment were simulated using Carrier's Hourly Analysis Program (HAP). The analysis of Green Building Design showed significant improvement compared with the existing building design. The analysis of a building’s HVAC design is carried out to highlight the benefits of achieving LEED standard in the UMT building.
To investigate near wall effects of UV water disinfection reactor using CFD
(UMT, Lahore, 2019) Muhammad Yasir
Many improvements have been presented on the Ultra-violet (UV) disinfection reactor geometry in which lamp configuration, wall roughness and hydrodynamics were the main focus of the research. The turbulence of the fluid flow is significantly influenced by the presence of the wall, since it is modified by the nearness of the wall in a non-minor way. Unfortunately, no single model of turbulence is available that could deal the complexity of the fluid flow on the wall. Wall function is the pivotal to control the turbulence on the wall, different functions available which control the individual layer of the wall region. In our study we have used different wall function numerical approaches of the computational fluid dynamics (CFD) to study the effects of fluent turbulence on the reduction equivalent dose (RED) in the UV disinfection Reactor Model. For our turbulence model we used K-elipson to calculate RED under different wall functions (standard, scalable, non-equilibrium, enhanced wall treatment). Discrete ordinates radiation model was used and simulated for the UV lamp inside the reactor chamber, which has been ended up being a solid instrument for fluence rate (FR) displaying circulations in our UV reactor. Onwards critical parameter of wall functions was highlighted. We have investigated near wall effects of water disinfection and calculated the RED on each wall function with variable pathogen velocities. The simulation results provide the valuable understanding about how the RED differ or remains same between wall functions of single annular water disinfection reactor.