Energy Systems Commons^™

Capillary Forces And Wetting Dynamics By Diffuse-Interface Modeling, Fanny Thomas

Dissertations and Theses

Wetting phenomena underlie many natural and industrial processes, from the proper functioning of the lungs to the thin coating of surfaces. The three-phase interactions involved at microscopic scales play a critical role. Adding solid particles to an emulsion, for example, can drastically change the flow behavior due to capillary bridging between the particles. The study of these three-phase systems is especially relevant to the petroleum industry, where gas hydrates forming large clusters in subsea pipelines during crude oil transportation is a major concern. The dynamics of such systems is also of great interest from a fundamental perspective. Indeed describing non-equilibrium …

On The Energy Sustainability Of Active And Passive Building Integrated Technologies In The Context Of A Changing Climate For Tropical Coastal Cities, Rabindra Pokhrel

Dissertations and Theses

Caribbean Sea surface temperatures have been rising at an alarming rate of 0.020C/year. The effect of rising sea surface temperatures is reflected in increasing in 2m air temperature over the Caribbean. The rise in extreme temperatures increases human discomfort and energy demands for air conditioning (AC) putting both the population and energy infrastructure at higher risk of vulnerability. This vulnerability is amplified in compact cities where anthropogenic heat removal from the built environment further increases the temperature of the urban canyon with feedback on human comfort and energy demands. Although there has been prior work reported on mitigating energy demands …

Utility-Scale Solar Pv Performance Enhancements Through System Level Modifications, Andrew D. S. Glick, Naseem Ali, Juliaan Bossuyt, Marc Calaf, Raúl Bayoán Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Performance of solar PV diminishes with the increase in temperature of the solar modules. Therefore, to further facilitate the reduction in cost of photovoltaic energy, new approaches to limit module temperature increase in natural ambient conditions should be explored. Thus far only approaches based at the individual panel level have been investigated, while the more complex, systems approach remains unexplored. Here, we perform the first wind tunnel scaled solar farm experiments to investigate the potential for temperature reduction through system-level flow enhancement. The percentage of solar irradiance converted into electric power depends upon module efficiency, typically less than 20%. The …

A Study On The Hydrodynamics Of A Bench-Scale Top-Fed Bubbling Fluidized Bed Gasifier Using Biomass And Coal As Feedstocks, Ali Can Sivri

Graduate Theses, Dissertations, and Problem Reports (ETD)

The production of synthetic gas (syngas) from renewable or carbon-neutral sources can significantly reduce greenhouse and other emissions associated with conventional fuels. One of the most promising technologies to efficiently convert carbonaceous feedstocks such as biomass, coal, or municipal waste into syngas for transportation, power, heat, electricity generation, and or production of added-value chemicals is the bubbling fluidized-bed gasifier (BFBG). However, the gasification process inside a BFBG is a very complex high-temperature multiphase flow phenomena still not well understood, particularly when binary mixtures are investigated. As a result, despite the numerous correlations in the literature developed to predict the hydrodynamics …

An Examination To Pathways Powering Car Using Clean Energy, Marina Miranda

Graduate Theses, Dissertations, and Problem Reports (ETD)

Traditional vehicles powered by internal combustion engines contribute significantly to increasing emissions of greenhouses gasses (GHG). There has been increasing interest in powering vehicles using green energy include using electricity produced by wind turbine and solar panel. The green electricity can be used to directly charge the Battery Electric Vehicles (BEV), or producing hydrogen as fuel for Fuel Cell Electric Vehicles (FCEV) by converting electrical energy to hydrogen (H₂) through water electrolysis. The low energy density H₂ produced can be stored on board as either compressed H₂ or liquefied H₂.

This research examines the …

Evaluation Of Process And Economic Feasibility Of Implementing A Topping Cycle Cogeneration System, Unique Karki

Graduate Theses, Dissertations, and Problem Reports (ETD)

Industrial applications that require steam for their end-uses generally utilize steam boilers that are at higher size than what is typically required. Similarly, gas turbine-based power plants corroborate the gas turbine system and eventually relieve the exhaust into the atmosphere. These facilities include food, paper, chemicals, refining, and primary metal manufacturing industries. This research focuses on the scope of a topping cycle combined heat and power (CHP) system by pushing the load on the boiler to a higher limit, or a gas turbine operation in place of a boiler system for a topping cycle CHP and its economic feasibility by …

Development Of An Activity-Based Windowing Approach To Evaluate Real-World Nox Emissions From Modern Medium And Heavy-Duty Diesel Trucks, Rasik Pondicherry

Graduate Theses, Dissertations, and Problem Reports (ETD)

The introduction of in-use emissions regulations by the United States Environmental Protection Agency (U.S.EPA) requires medium-duty (MD) and heavy-duty (HD) engine manufacturers to demonstrate emissions compliance during in-fleet operation. In the United States (U.S.), the Not-to-Exceed (NTE) method is used to evaluate real-world emissions compliance from on-highway MD and HD trucks. Regulatory agencies, engine manufacturers and research entities have identified that the NTE method incorporates numerous exclusions and evaluates emissions compliance only under selective operating conditions that are favorable for the selective catalytic reduction (SCR) system to reduce oxides of nitrogen (NOx) emissions efficiently. Such operation is typically encountered only …

Experimental And Computational Characterization Of Sodium Nitrate @ Silica Nano Capsules For Thermal Energy Storage Applications, Wataru Hashimoto

Graduate Research Theses & Dissertations

In this investigation, a nanocapsule composed of a sodium nitrate core and a silicon dioxide shell is synthesized, characterized, and analyzed utilizing a mixture of analytical and computational tools. The sol-gel method was selected as the process of nanoencapsulation. Analytical characterization techniques employed in this investigation include differential scanning calorimetry (DSC) to measure melting temperatures and enthalpies of fusion, dynamic light scattering (DLS) to calculate particle size distributions, scanning electron microscopy (SEM) to analyze surface characteristics, transmission electron microscopy (TEM) to perform shell characterization, and energy dispersive X-ray spectroscopy (EDS) to determine chemical composition. Preliminary results indicated a decrease in …

Numerical Investigation Of Darrieus Wind Turbine With Slotted Airfoil Blades, Ahmed Elbaz, Omar Sherif Mohamaed, Ahmed Abdelhamid Ibrahim, Ahmed Khaled Etman, Amr A. Abdelfattah

Mechanical Engineering

Low starting torque is considered as one of the major drawbacks of Darrieus type vertical axis wind turbine (VAWT). Design optimization to overcome this problem by modifying the airfoil geometry has received great attention by the wind energy community. Moreover, efforts have been directed towards augmenting the power coefficient of the turbine. In the present work, the effect of employing slotted airfoil as turbine blade on the performance and starting characteristics has been investigated. The slot parameters; slot location, angle of inclination, and dimensions, were optimized for NACA 0018 airfoil which is commonly used in Darrieus turbines. The flow over …

Carbon-Based Interlayers In Perovskite Solar Cells, Aleksandr P. Litvin, Xiaoyu Zhang, Kevin Berwick, Anatoly V. Fedorov, Weitao Zheng, Alexander V. Baranov

Articles

Perovskites are solution-processed, high-performance semiconductors of interest in low-cost photovoltaics. The interfaces between the perovskite photoactive layers and the top and bottom contacts are crucial for efficient charge transport and minimizing trapping. Control of the collection of charge carriers at these interfaces is decisive to device performance. Here, we review recent progress in the realization of efficient perovskite solar cells using cheap, easily processed, stable, carbon-based interlayers. Interface materials including graphene, carbon nanotubes, fullerenes, graphene quantum dots and carbon dots are introduced and their influence on device performance is discussed.

A Solar‐Driven Membrane‐Based Water Desalination/Purification System, Abdellah Shafieian Dastjerdi

Theses: Doctorates and Masters

Lack of fresh water has turned into one of the major challenges of the world in the present century. Desalination of brackish or seawater has been proven to be one of the best solutions to cope with this global challenge. Among all the desalination methods, Membrane Distillation (MD) is well known as a cost effective and profitable technology for treating saline water. However, higher energy consumption compared to other separation techniques has been reported as MD’s main drawback. That is why the application of solar energy to provide the thermal energy requirement of MD modules has been the focal point …

Measured And Modeled Performance Of A Spring Dominant Free Piston Engine Generator, Ramanjaneya Mehar Baba Bade

Graduate Theses, Dissertations, and Problem Reports (ETD)

Free Piston Engine Generators (FPEG) directly convert the reciprocating piston motion into electricity by using a linear alternator. Unlike conventional engines with piston motion restricted by a crankshaft mechanism, the FPEG piston motion is constrained by the energy available in the system. When stiff springs are considered in the design, the FPEG system attains high frequency with high power and efficiency. The main objective of this research was to model stiff spring-assisted FPEG system dynamics and performance accurately, and to apply the modeling results to the development of a 1kW, spark ignited, natural gas fueled, FPEG experimental prototype. The experimental …

Measurement Of Current Distribution In The Land Channel Direction Of A Proton Exchange Membrane Fuel Cell, Chinmay Kulkarni

Dissertations, Master's Theses and Master's Reports

A fully functional proton exchange membrane fuel cell with single land channel geometry on the cathode and segmented anode current collector with 9 mm² active area with a 350μm spatial resolution was utilized to measure the local current distribution in the land channel direction. A distinguished printed circuit board approach was used for the data acquisition to adapt to any flow field design.

Performance of this segmented cell was examined at dry, wet and moderate humidity settings to study the water transport phenomenon in the PEMFC. In the dry condition at 60 ͦ C with 0% relative humidity, the …

High-Performance Zero Liquid Discharge (Zld) Treatment Of High-Salinity Brines Using A Multiple-Effect Absorption Distillation Concept, Sunil Pinnu

Dissertations, Master's Theses and Master's Reports

State-of-the-art zero liquid discharge (ZLD) technologies are currently bound with either intensive use of high-grade electrical energy such as mechanical vacuum vapor compressors utilized in brine crystallizers or high capital cost with environmental concerns such as evaporation ponds. The present study aims to address these issues by an innovative desiccant-based ZLD system in which a multiple-effect distillation (MED) unit is uniquely embedded at the heart of an absorption-desorption system. Here, the MED and absorption systems are inherently coupled enabling both heat and mass transfer processes between a high-salinity water and a desiccant solution. The proposed technology employs an absorption-based thermally-driven …

The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1

Tanzania Journal of Engineering and Technology (TJET)

Worldwide, every day human beings generate millions of tons of Faecal Sludge (FS), which is rich in water, nutrients, energy, and organic compounds. Yet FS is not being managed in a way that permits us to derive value from its reuse, while at the same time, millions of farmers struggle with depleted soils and lack of water. In most of the developing countries, energy for cooking is mainly derived from cutting of trees, either as wood or charcoal. Resource recovery and reuse from FS can create livelihoods, enhance food security, support green economies, reduce waste and contribute to cost recovery …

Synthesis And Connection Of Iridium Hydrogen Evolution Catalyst To Chlorella Vulgaris Photosystem I For Light-Driven Hydrogen Evolution, Anna Ramirez

Honors Program Theses and Projects

Hydrogen gas has been shown to be a promising energy source as options other than fossil fuels are being looked at in the face of anthropogenic climate change. It is known that anthropogenic climate change is caused by the production of greenhouse gases being let into the atmosphere, specifically a common reason for this is the burning of fossil fuels for energy. The overall goal of this project is to design a biochemical hybrid system that will be used to make H 2 gas and does not require the use of fossil fuels. Burning hydrogen as fuel produces only water …

City Of New Smyrna Beach Solar Feasibility Assessment, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

At the request of the City of New Smyrna Beach, the Florida Solar Energy Center (FSEC) assessed rooftop solar and building energy efficiency improvement potential for 17 city-owned facilities. The intent has been to assist City leaders in identifying opportunities to reduce the City's overall electricity consumption and increase its use of renewable energy.

The FSEC team conducted Level 1 energy audit activities and site assessments including:

On-site assessment

• Solar feasibility measurements and characterization including orientation, roof shading (adjacent structures, encroaching trees, etc.), available roof area, system output, annualized savings
• HVAC characterization
• Lighting survey
• Occupancy density, schedule, thermostat settings

Post …

Experimental Study Of Condensation In A Thermoacoustic Cooler With Various 3d Printed Regenerators Using Water Vapor As The Working Fluid, Aibek Bekkulov, Andrew Luthen, Ben Xu

Mechanical Engineering Faculty Publications

Thermoacoustics (TA) deals with the conversion of heat into sound and vice versa. The device that transfers energy from a low temperature reservoir to a high temperature one by utilizing acoustic work is called TA cooler (TAC). The main components of a typical TAC are a resonator, a porous regenerator (e.g. stack of parallel plates) and two heat exchangers. The thermoacoustic phenomenon takes place in the regenerator where a nonzero temperature gradient is imposed, and interacts with the sound wave. The low temperature at the cold end of TAC can be used to condense water from the humid air and …

Energy Performance Certification: Misassessment Due To Assuming Default Heat Losses, Ciara Ahern, Brian Norton

Articles

Energy Performance Certificates (EPCs) are issued when dwellings are constructed, sold or leased in the EU. Where the cost of obtaining the required data is prohibitive, EPC assessors use nationally applicable default-values. To ensure that dwellings are not assigned a wrongly-higher EPC rating, a standardised thermal bridging transmittance coefficient (Y-value) is typically adopted for all existing dwellings while worst-case overall heat loss coefficients (U-values) are used. Default U-values are applied to a specific building element type (roof, wall, floor etc.) based on building codes and regulations applicable at time of construction. Due to significant building fabric upgrades, default U-values are …

A Generalisable Bottom-Up Methodology For Deriving A Residential Stock Model From Large Empirical Databases, Ciara Ahern, Brian Norton

Articles

Specifying representative reference buildings as a prerequisite for calculating cost-optimal energy performance requirements for buildings and building elements. Appropriate characterisation is prerequisite data for an overall national building energy consumption model to produce valid outcomes. Energy Performance Certificates (EPCs) are issued in the EU, for dwellings whenever they are constructed, sold or leased. Where acquiring data for an EPC would be prohibitively costly, nationally applicable default-values are employed for the building envelope thermal transmittance coefficients. Significant levels of retrofits led to the default-values used now being higher than is typical in reality, leading to characterisations of reference dwellings based on …