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Articles 1 - 18 of 18
Full-Text Articles in Engineering
Utility-Scale Solar Pv Performance Enhancements Through System Level Modifications, Andrew D. S. Glick, Naseem Ali, Juliaan Bossuyt, Marc Calaf, Raúl Bayoán Cal
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 …
Utility-Scale Solar Pv Performance Enhancements Through System-Level Modifications, Andrew D. S. Glick, Naseem Ali, Juliaan Bossuyt, Marc Calaf, Raul Bayoan Cal
Utility-Scale Solar Pv Performance Enhancements Through System-Level Modifications, Andrew D. S. Glick, Naseem Ali, Juliaan Bossuyt, Marc Calaf, Raul Bayoan 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 …
Planning For Change In The Electric Power Industry: A Primer For Transactive Energy Scenario Development, Joshua Binus
Planning For Change In The Electric Power Industry: A Primer For Transactive Energy Scenario Development, Joshua Binus
Engineering and Technology Management Faculty Publications and Presentations
The electric power industry and its associated infrastructures (a.k.a. "the grid") are evolving from centrally planned, organized, and operated networks of players, technologies, and resources to systems of systems that are increasingly digitized and distributed in their operation and innovative capacity. Subsequently, strategic planners and technology managers associated with the electric power industry are faced with a range of scenarios to evaluate, including one that considers the emergence of commercialized transactive energy systems in the coming ten-year time horizon. The crafting of a transactive energy scenario can help inform technology innovation and management efforts that benefit consumers, electricity providers, and …
Assessing Spacing Impact On Coherent Features In A Wind Turbine Array Boundary Layer, Naseem Ali, Nicholas Hamilton, Dominic Delucia, Raúl Bayoán Cal
Assessing Spacing Impact On Coherent Features In A Wind Turbine Array Boundary Layer, Naseem Ali, Nicholas Hamilton, Dominic Delucia, Raúl Bayoán Cal
Mechanical and Materials Engineering Faculty Publications and Presentations
As wind farms become larger, the spacing between turbines becomes a significant design consideration that can impose serious economic constraints. To investigate the turbulent flow structures in a 4 x 3 Cartesian wind turbine array boundary layer (WTABL), a wind tunnel experiment was carried out parameterizing the streamwise and spanwise wind turbine spacing. Four cases are chosen spacing turbines by 6 or 3D in the streamwise direction, and 3 or 1:5D in the spanwise direction, where D = 12 cm is the rotor diameter. Data are obtained experimentally using stereo particle image velocimetry. Mean streamwise velocity showed maximum …
Torrefaction Kinetics Of Hemp Hurds, An Emerging Agricultural Byproduct, In A Small Retort, Tel Jensen
Torrefaction Kinetics Of Hemp Hurds, An Emerging Agricultural Byproduct, In A Small Retort, Tel Jensen
Civil and Environmental Engineering Undergraduate Honors Theses
As knowledge concerning the consequences of unsustainable energy sources and agricultural practices grows, development of low-impact alternatives to both becomes more important. Sustainable sources of biomass offer solutions to both problems. This study characterized the reaction kinetics of torrefying an agricultural byproduct, the woody interior of hemp stems, or hurds. Torrefaction was carried out at 250 °C in small and simple retorts made of galvanized steel pipe. A first-order model most closely approximated the reaction. A sensitivity analysis was performed and the data was adjusted to correct for three potential sources of error, and regressed to find the best fit …
Deposition Velocity Dependence On Urban Morphology, Rawand Muzafar Rasheed
Deposition Velocity Dependence On Urban Morphology, Rawand Muzafar Rasheed
Undergraduate Research & Mentoring Program
Understanding the interactions between the atmospheric boundary layer and urban structures provides insights into emerging problems such as green building design as well as dispersion and deposition of pollutants on urban structures. Characterization of deposition velocity dependence through the naphthalene sublimation method on model urban structures is conducted herein where the analogous fundamental transport mechanisms of momentum and mass transport is obtained via mass of naphthalene transferred. Via wind tunnel experiments, results show that deposition velocity of naphthalene from urban structures increases with increased number of urban structures ahead of the point of investigation. This is attributed to the wakes …
Wake Character In The Wind Turbine Array: (Dis-)Organization, Spatial And Dynamic Evolution And Low-Dimensional Modeling, Nicholas Michael Hamilton
Wake Character In The Wind Turbine Array: (Dis-)Organization, Spatial And Dynamic Evolution And Low-Dimensional Modeling, Nicholas Michael Hamilton
Dissertations and Theses
To maximize the effectiveness of the rapidly increasing capacity of installed wind energy resources, new models must be developed that are capable of more nuanced control of each wind turbine so that each device is more responsive to inflow events. Models used to plan wind turbine arrays and control behavior of devices within the farm currently make questionable estimates of the incoming atmospheric flow and update turbine configurations infrequently. As a result, wind turbines often operate at diminished capacities, especially in arrays where wind turbine wakes interact and inflow conditions are far from ideal. New turbine control and wake prediction …
Design For Fractal Grid Generated Turbulence, Moira Gion
Design For Fractal Grid Generated Turbulence, Moira Gion
Undergraduate Research & Mentoring Program
Fractal geometry can be used to find organization or order in something that appears to be in disorder, or chaos. Turbulence is viewed as one place where fractal geometry can be found in nature. The irregularity in fluid flow is dependent on the initial conditions. In the past, the idea of self-similarity has been used to develop statistical theories of energy cascade in a turbulent flow. Recent studies have done experiments on obstructing flows with fractal objects to observe intermittency, (or self-similarity) within a turbulent flow. Experiments on fractal grid generated turbulence has been performed by other research groups, so …
Vortex Identification In The Wake Of A Wind Turbine Array, Aleksandr Sergeyevich Aseyev
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
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
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 …
Anisotropy Of The Reynolds Stress Tensor In The Wakes Of Counter-Rotating Wind Turbine Arrays, Nicholas Michael Hamilton
Anisotropy Of The Reynolds Stress Tensor In The Wakes Of Counter-Rotating Wind Turbine Arrays, Nicholas Michael Hamilton
Dissertations and Theses
A wind turbine array was constructed in the wind tunnel at Portland State University in a standard Cartesian arrangement. Configurations of the turbine array were tested with rotor blades set to rotate in either a clockwise or counter-clockwise sense. Measurements of velocity were made with stereo particle-image velocimetry. Mean statistics of velocities and Reynolds stresses clearly show the effect of direction of rotation of rotor blades for both entrance and exit row turbines. Rotational sense of the turbine blades is visible in the mean spanwise velocity W and the Reynolds shear stress -[macron over vw]. The normalized anisotropy tensor was …
A Parametric Study On Power Variation For Model Wind Turbine Arrays, Dominic Delucia
A Parametric Study On Power Variation For Model Wind Turbine Arrays, Dominic Delucia
Dissertations and Theses
This thesis presents the results of wind tunnel experiments performed for various model wind turbine arrays. The aim is to understand how siting affects power output. To optimize wind farm efficiency the experiments vary the parameters of the model wind turbines and the layout of the wind turbine array. The parameters include the alignment, height, spacing, and the rotational direction of the model wind turbines. These experiments employ mechanical torque sensors to simultaneously measure the torque and rotor angular velocity, which yields a direct measurement of the fluid mechanical power extracted by the turbine at multiple locations. For a 4 …
The Effect Of Microencapsulated Phase-Change Material On The Compressive Strength Of Structural Concrete, Chad Norvell, David J. Sailor, Peter Dusicka
The Effect Of Microencapsulated Phase-Change Material On The Compressive Strength Of Structural Concrete, Chad Norvell, David J. Sailor, Peter Dusicka
Mechanical and Materials Engineering Faculty Publications and Presentations
Latent heat energy storage through phase-change materials (PCMs) is one possible strategy to control interior temperatures in buildings, improve thermal comfort, and passively reduce building energy use associated with heating and cooling. While PCMs integrated into building structure elements have been studied since the 1970s, challenges of integrating PCMs into building materials while maintaining their heat storage benefits have limited their application in practice. The recent introduction of microencapsulated phase-change materials provides the energy storage capability of PCMs in micron-scale, chemically-inert capsules that can be easily integrated into composite materials such as gypsum wallboard and concrete. The size and physical …
Assessment Of Solar Photovoltaic Technologies Using Multiple Perspectives And Hierarchical Decision Modeling, Nasir Jamil Sheikh
Assessment Of Solar Photovoltaic Technologies Using Multiple Perspectives And Hierarchical Decision Modeling, Nasir Jamil Sheikh
Dissertations and Theses
The objective of this research is to build a decision model for a comprehensive assessment of solar photovoltaic technologies using multiple perspectives. These perspectives include: social, technological, economic, environmental, and political (STEEP) with each perspective consisting of multiple criteria. Hierarchical decision modeling and expert judgment quantification are used to provide the relative ranking of the perspectives and criteria. Such modeling is effective in addressing technology evaluations with competing and contrasting perspectives and criteria where both quantitative and qualitative measurements are represented. The model is then operationalized by constructing desirability functions for each criterion. The combined results provide an overall numerical …
A Feasibility Study Of Model-Based Natural Ventilation Control In A Midrise Student Dormitory Building, Steven James Gross
A Feasibility Study Of Model-Based Natural Ventilation Control In A Midrise Student Dormitory Building, Steven James Gross
Dissertations and Theses
Past research has shown that natural ventilation can be used to satisfy upwards of 98% of the yearly cooling demand when utilized in the appropriate climate zone. Yet widespread implementation of natural ventilation has been limited in practice. This delay in market adoption is mainly due to lack of effective and reliable control. Historically, control of natural ventilation was left to the occupant (i.e. they are responsible for opening and closing their windows) because occupants are more readily satisfied when given control of the indoor environment. This strategy has been shown to be effective during summer months, but can lead …
Phase Change Materials As A Thermal Storage Device For Passive Houses, Kevin Ryan Campbell
Phase Change Materials As A Thermal Storage Device For Passive Houses, Kevin Ryan Campbell
Dissertations and Theses
This study describes a simulation-based approach for informing the incorporation of Phase Change Materials (PCMs) in buildings designed to the "Passive House" standard. PCMs provide a minimally invasive method of adding thermal mass to a building, thus mitigating overheating events. Phase change transition temperature, quantity, and location of PCM were all considered while incrementally adding PCM to Passive House simulation models in multiple climate zones across the United States. Whole building energy simulations were performed using EnergyPlus from the US Department of Energy. A prototypical Passive House with a 1500 Watt electric heater and no mechanical cooling was modeled. The …
Using Building Energy Simulation And Geospatial Modeling Techniques In Determine High Resolution Building Sector Energy Consumption Profiles, Shem C. Heiple
Using Building Energy Simulation And Geospatial Modeling Techniques In Determine High Resolution Building Sector Energy Consumption Profiles, Shem C. Heiple
Dissertations and Theses
A technique is presented for estimating hourly and seasonal energy consumption profiles in the building sector at spatial scales down to the individual taxlot or parcel. The method combines annual building energy simulations for cityspecific prototypical buildings and commonly available geospatial data in a Geographical Information System (GIS) framework. Hourly results can be extracted for any day and exported as a raster output at spatial scales as fine as an individual parcel (