Mechanical Engineering Commons^™

Computational Simulation Of Mass Transport And Energy Transfer In The Microbial Fuel Cell System, Shiqi Ou

Doctoral Dissertations

This doctoral dissertation introduces the research in the computational modeling and simulation for the microbial fuel cell (MFC) system which is a bio-electrochemical system that drives a current by using bacteria and mimicking bacterial interactions found in nature. The numerical methods, research approaches and simulation comparison with the experiments in the microbial fuel cells are described; the analysis and evaluation for the model methods and results that I have achieved are presented in this dissertation.

The development of the renewable energy has been a hot topic, and scientists have been focusing on the microbial fuel cell, which is an environmentally-friendly …

Impurity Effects In All-Vanadium Redox Flow Batteries, Andrew William Burch

Masters Theses

In this dissertation, the effects of VOSO₄ [vanadyl sulfate] source and impurities on the beginning-of-life (BOL) performance of an all-vanadium redox flow battery (VRFB) are explored. Battery performance was monitored at 50% state of charge (SOC) using electrolyte with VOSO₄ purities of 99%, 99.9% and 99.99% by weight. At cell potentials of 1.23V, the least pure solution yielded the lowest current density of 280 mA/cm² [square centimeter] and the most pure solution yielded the highest, 560 mA/cm². The voltage efficiencies and charge-discharge capacities were shown to follow the same trends. Scanning electron microscopy (SEM) images …

Industrial Energy Consumption, Benchmarking, And Analysis In The United States, Daniel Maldonado

Mechanical Engineering Undergraduate Honors Theses

The purpose of this paper is to analyze the energy consumption of the industrial sector in the United States, and to identify the tools that can be used to minimize the consumption and improve the energy efficiency of all facilities in the country. The first part of the paper is a historical analysis of the industrial sector energy consumption, where the different energy sources are identified. The second part details different electronic tools that will provide facilities the ability of performing benchmarking, in order to understand their energy performance. Finally, the third part of this paper provides information about the …

A Look At Commercial Building Energy Use And Energy Efficiency Technologies From 1980 To Present, Marvin M. Arroyo

Mechanical Engineering Undergraduate Honors Theses

Energy consumption has increased considerably in the last fifty years as population rises. At the same time, design and efficiency of all equipment used in commercial buildings have changed as well. The purpose of this thesis is to explain how HVAC systems have changed and how they have affected energy consumption. Entities like the US Department of Energy (DOE) and the US Energy Information Administration (EIA) facilitate the data-gathering process by offering databases of energy information from actual monthly energy bills to promote public understanding of energy and its interaction with the economy and the environment. Moreover, in order to …

Simulation Of An Air Cooled Single-Effect Solar Absorption Cooling System With Evacuated Tube Collectors, Mohsen Jahandardoost

UNLV Theses, Dissertations, Professional Papers, and Capstones

Consistently increasing CO2 emission and ozone depletion from synthetic refrigerants are serious environmental issues challenging the scientific community. Absorption cooling systems give scope of utilizing low grade energy source for generating cooling effect. Solar energy is one of these low grade energy sources and with considering the fact that cooling demand increases with the intensity of solar radiation, solar refrigeration has been considered as a logical solution.

This thesis consists of two different simulation stages, in the first stage, a single effect lithium bromide absorption cooling system with constant cooling capacity is modeled and the effect of ambient and generator …

Evaluation Of Two-Phase Evaporation Pressure Drop Correlations For Low Refrigerant Mass Flux., Anna Fenko

Electronic Theses and Dissertations

This study was conducted to evaluate three currently popular two-phase pressure drop models for extremely low velocity refrigerant flow through smooth circular evaporators in household refrigeration systems. Experimental data was taken at mass fluxes under 70 kg/m²s for two refrigerants, R134A and R600A, internal diameters of aluminum evaporators ranging from 0.186 to 0.317 inches, U-bend internal radii ranging from 0.342 to 0.750 inches in horizontal and vertical orientations of evaporators. The geometry of the samples closely resembled a commonly used serpentine shape with multiple U-bends experiencing both, up- and down-flow of the refrigerant. Two empirical models, Müller-Steinhagen & …

Optimization Of Titanium Liquid/Gas Diffusion Layers In Proton Exchange Membrane Electrolyzer Cells, Stuart Mccoy Steen

Masters Theses

Polymer electrolyte membrane electrolyzer cells (PEMECs), which are reverse PEM fuel cells (PEMFCs), are effective energy storage medium by producing hydrogen/oxygen from water using electricity from renewable energy sources. This is due in part because of its efficiency, high energy density, compact design, and large capacity. In a PEMEC, a liquid/gas diffusion layer (LGDL) is located between the catalyst layer and the current distributing flow field. The LGDL is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. Carbon materials (carbon paper or carbon cloth), typically used …

Thermal Hydraulic Turbine Dynamometer, Ryan Baskett, Alexander Campbell, Andrew Puntorno-Carlberg

Mechanical Engineering

No abstract provided.

High Temperature Hepa Filter Test Unit Upgrades, Alexander Krippner, Ian Corcorran, Michael Burlando

Mechanical Engineering

No abstract provided.

Wind Power Capacity Value Metrics And Variability: A Study In New England, Frederick W. Letson

Doctoral Dissertations

Capacity value is the contribution of a power plant to the ability of the power system to meet high demand. As wind power penetration in New England, and worldwide, increases so does the importance of identifying the capacity contribution made by wind power plants. It is critical to accurately characterize the capacity value of these wind power plants and the variability of the capacity value over the long term. This is important in order to avoid the cost of keeping extra power plants operational while still being able to cover the demand for power reliably. This capacity value calculation is …

An Application Of Path-Percolation Theory And Lattice-Boltzmann Model On Mass Transfer In Inhomogeneous Porous Media, Ozgur Cekmer

Doctoral Dissertations

In this dissertation, random inhomogeneous porous channels were generated statistically, and single- and multi-phase flow models were developed to investigate diffusion behavior of gases in porous media. Three different methods were used to simulate inhomogeneous porous flow channels. First, the path-percolation theory was adapted in diffusion studies to generate random high-tortuosity (above 1.07) porous channels with a desired porosity within a specified confidence level. Cluster labeling process was applied to simulate paths for the gas molecules, and the resulting effective porosity was investigated statistically. Second, the double-path-percolation theory was introduced to simulate low-tortuosity (between 1.0005 and 1.0700) flow channels. Using …

Thermodynamic Analysis Of The Application Of Thermal Energy Storage To A Combined Heat And Power Plant, Benjamin Mcdaniel

Masters Theses

The main objective of this paper is to show the economic and environmental benefits that can be attained through the coupling of borehole thermal energy storage (BTES) and combined heat and power (CHP). The subject of this investigation is the University of Massachusetts CHP District Heating System. Energy prices are significantly higher during the winter months due to the limited supply of natural gas. This dearth not only increases operating costs but also emissions, due to the need to burn ultra low sulfur diesel (ULSD). The application of a TES system to a CHP plant allows the plant to deviate …

Solar Cal Poly Active Hvac Project, James Cornish, Jake Cosmo, Patrick Weston

Mechanical Engineering

For this project, the goal was to conceptualize, design, test, and implement an active HVAC system to be used in the Solar Cal Poly house competing in the Department of Energy’s 2015 Solar Decathlon. With many house iterations, it was decided to use a split system with an outdoor heat pump and indoor air handler, paired with a HRV for ventilation. Through system modeling using Design Builder and Energy Pro 6.5, the cooling load of the house was determined along with the cooling schedule. The foreseen safety precautions and limited construction time guided the entire project, along with the active …

Conversion Of A Gas Combustion Engine To An Electric Motor In A Porsche 924, Ashley Weed

BioResource and Agricultural Engineering

This paper is a walk-through of converting a gasoline Porsche 924 to and electric engine. The paper begins with steps on how to remove the gasoline engine. It then goes into setting up the electrical system for the new electric vehicle and then follows up with the motor installation. The end of the report discusses the testing and results of the electric vehicle and finishes up with recommendations to anyone who attempts a similar project.

Shark Alert: Early Warning System, Cory Peterson, Marc Rauschnot, Taylor Mcclain

Electrical Engineering

The Shark Alert Early Warning System is a device geared toward avid beach goers such as surfers, divers, and swimmers. The system is composed of an ultrasonic transmitter mounted on a shark’s dorsal fin and a receiver worn by the user around the ankle. The receiver alerts the user to the presence of a shark upon ultrasonic signal detection.

The receiver warns the user through both visual and tactile (vibration) alerts to ensure user notification. This circuit was built and tested in the EE labs and Recreation Center pools to determine transmission range. The receiver detects the transmitted signal up …

Increasing Isentropic Efficiency With Hydrostatic Head And Venturi Ejection In A Rankine Power Cycle, Nathan Daniel Ruiz

Master's Theses

This thesis describes the modifications made to the Cal Poly Thermal Science Laboratory’s steam turbine experiment. While the use of superheating or reheating is commonly used to increase efficiency in a Rankine cycle the methods prove unfeasible in a small scale project. For this reason, a mathematical model and proof of concept design using hydrostatic head generated by elevation and venturi ejection for use by the condenser is developed along with the equations needed to predict the changes to the system. These equations were used to create software to predict efficiency as well as lay down the foundation for future …

Solar Decathlon 2015, Solar Cal Poly; Solar Cal Poly Project Engineers, Cristina Paquin, Julien Blarel, Sanchit Joshi

Mechanical Engineering

No abstract provided.

Power Maximization Of A Three-Phase Hydrokinetic Turbine, Matthew Carleson

Senior Theses

As Earth`s expendable resources dwindle, the need for alternative, renewable energy sources grows. Out of this need, an old favorite source is rising in popularity: small water turbines. Water-driven turbines first began as a means for turning mills and eventually evolved into massive dams that can power whole regions. This project focused on the construction of, and testing the properties of, a small pico-hydro power turbine. By using compressed air to drive the turbine, a representation of the peak power output was measured, serving as a basis for determining the value of pico-power systems in regards to the world`s current …

Improved Methods For Identifying, Applying, And Verifying Industrial Energy Efficiency Measures, Andrew Chase Harding

Graduate Theses and Dissertations

Energy efficiency is the least expensive source of additional energy capacity for today's global energy expansion. Energy efficiency offers additional benefits of cost savings for consumers, reduced environmental impacts, and enhanced energy security. The challenges of energy efficiency include identifying potential efficiency measures, quantifying savings, determining cost effectiveness, and verifying savings of installed measures. This thesis presents three separate chapters which address these challenges. The first is a paper presented at the 2014 industrial energy technology conference (IETC) that details a compressed air system project using the systems approach to identify cost effective measures, energy intensity to project savings, and …

Maximum Power Point Tracking And Solar Power For Developing Countries Around The World, Christopher M. Plate

Electrical Engineering Undergraduate Honors Theses

Renewable energy is becoming increasingly important as more and more countries become industrialized. Using solar power as opposed to fossil fuels and coal is becoming cheaper and easier to access throughout the world, yet there are still efficiency hurdles to be overcome. Designing a cheap, easily modifiable and reparable Maximum Power Point Tracker would be a stepping stone to bringing solar power to remote parts of the globe. Once designed and made portable, these devices could be distributed throughout developing countries to enhance renewable energy output. An Arduino-based tracker was chosen for ease of use and access. This base also …

Experimental Verification And Integration Of A Next Generation Smart Power Management System, Tavis Clemmer

Graduate Theses and Dissertations

With the increase in energy demand by the residential community in this country and the diminishing fossil fuel resources being used for electric energy production there is a need for a system to efficiently manage power within a residence. The Smart Green Power Node (SGPN) is a next generation energy management system that automates on-site energy production, storage, consumption, and grid usage to yield the most savings for both the utility and the consumer. Such a system automatically manages on-site distributed generation sources such as a PhotoVoltaic (PV) input and battery storage to curtail grid energy usage when the price …

Characterization Of Wake Effects And Loading Status Of Wind Turbine Arrays Under Different Inflow Conditions, Xiangyu Gao

Open Access Theses

The objective of the present work is to improve the accuracy of Actuator Line Modeling (ALM) in predicting the unsteady aerodynamic loadings on turbine blades and turbine wake by assessing different methods used to determine the relative velocity between the rotating blades and wind. ALM is incorporated into a Large Eddy Simulation (LES) solver in OpenFOAM (Open Field Operations and Manipulations). The aerodynamic loadings are validated by experiment results from National Renewable Energy Laboratory (NREL). Turbine wakes are validated by predictions of large eddy simulation using exact 3D blade geometries from a two-blade NREL Phase VI turbine. Three different relative …

Vortex Identification In The Wake Of A Wind Turbine Array, Aleksandr Sergeyevich Aseyev

Dissertations and Theses

Vortex identification techniques are used to analyze the flow structure in a 4 x 3 array of scale model wind turbines. Q-criterion, Δ-criterion, and λ₂-criterion are applied to Particle Image Velocimetry data gathered fore and aft of the last row centerline turbine. Q-criterion and λ₂-criterion provide a clear indication of regions where vortical activity exists while the Δ-criterion does not. Galilean decomposition, Reynolds decomposition, vorticity, and swirling strength are used to further understand the location and behavior of the vortices. The techniques identify and display the high magnitude vortices in high shear zones resulting from the …

Global Time-Independent Agent-Based Simulation For Transactive Energy System Dispatch And Schedule Forecasting, Shawn Aaron Chandler

Dissertations and Theses

Electricity service providers (ESP) worldwide have increased their interest in the use of electrical distribution, transmission, generation, storage, and responsive load resources as integrated systems. Referred to commonly as "smart grid," their interest is driven by widespread goals to improve the operations, management and control of large-scale power systems. In this thesis I provide research into a novel agent-based simulation (ABS) approach for exploring smart grid system (SGS) dispatch, schedule forecasting and resource coordination. I model an electrical grid and its assets as an adaptive ABS, assigning an agent construct to every SGS resource including demand response, energy storage, and …

Sensible Air To Air Heat Recovery Strategies In A Passive House, Santiago Martin Rodriguez-Anderson

Dissertations and Theses

Due to rising energy costs and concerns about global climate change, high performance buildings are more in demand than ever before. With roughly 20% of the total energy consumption in the United States being devoted to residential use, this sector represents a significant opportunity for future savings. There are many guidelines and standards for reducing building energy consumption. One of the most stringent is the Passive House Standard. The standard requires that that air infiltration is less than or equal to 0.6 air changes per hour at a 50 Pascal pressure difference (ACH 50), annual heating energy is less than …

Structural Analysis Of Integration Of A Non-Cylindrical Cng Fuel Tank, Prathamesh Prashant Deshpande

Dissertations, Master's Theses and Master's Reports - Open

The purpose of this study is to computationally model and analyze the vehicle frame which is mounted with a non-conventional, non-cylindrical compressed natural gas (CNG) fuel tank. Integration of this tank in the vehicle underbody will resolve the issue of reduced storage space which is observed in a conventional CNG powered vehicle. This research will ultimately result in making CNG a good alternative to gasoline and reducing the increasing dependency on a single fuel. This tank will be developed in two phases: phase I design of the tank will be a standard rectangular outer box shape with Schwarz P-surface inner …

Modeling Of Biomass Torrefaction And Pyrolysis And Its Applications, Jordan L. Klinger

Dissertations, Master's Theses and Master's Reports - Open

Utilizing biomass provides a possible near-term alternative solution for fossil energy dependence in both electricity generation and transportation. Though thermochemical conversion can produce solid/liquid fuels that are compatible in existing infrastructure, detailed scientific chemical and mechanistic understanding are still being developed. In contribution to these efforts, this work is focused on development of a semiempirical, lumped parameter, chemical kinetic model to describe the degradation of woody biomass.

The initial kinetic model was developed in the torrefaction region to describe the gas-phase evolution of products (water, organic acids, permanent gases, and furfural) through a three consecutive reaction model. In this model, …

Transient Thermoelectric Supercooling: Isosceles Current Pulses From A Response Surface Perspective And The Performance Effects Of Pulse Cooling A Heat Generating Mass, Alfred Piggott

Dissertations, Master's Theses and Master's Reports

With increased public interest in protecting the environment, scientists and engineers aim to improve energy conversion efficiency. Thermoelectrics offer many advantages as thermal management technology. When compared to vapor compression refrigeration, above approximately 200 to 600 watts, cost in dollars per watt as well as COP are not advantageous for thermoelectrics. The goal of this work was to determine if optimized pulse supercooling operation could improve cooling capacity or efficiency of a thermoelectric device. The basis of this research is a thermal-electrical analogy based modeling study using SPICE. Two models were developed. The first model, a standalone thermocouple with no …

Offshore Turbine Arrays: Numerical Modeling And Experimental Validation, Thomas Kroll, William Hall, Ian Gagnon

Honors Theses and Capstones

The interaction between wind turbines in a large wind farm needs to be better understood to reduce array losses and improve energy production. A numerical test bed for an array of offshore wind turbines was developed in the open-source computational fluid dynamics (CFD) framework OpenFOAM. It provides a computational tool which can be used in combination with physical model turbine array studies in the Flow Physics Facility (FPF) at UNH as well as other test facilities.

Turbines were modeled as actuator disks with turbulence sources to reduce computational cost. Both k-ϵ and k-ω SST turbulence models were utilized to capture …