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Description
As the photovoltaic (PV) power plants age in the field, the PV modules degrade and generate visible and invisible defects. A defect and statistical degradation rate analysis of photovoltaic (PV) power plants is presented in two-part thesis. The first part of the thesis deals with the defect analysis and the

As the photovoltaic (PV) power plants age in the field, the PV modules degrade and generate visible and invisible defects. A defect and statistical degradation rate analysis of photovoltaic (PV) power plants is presented in two-part thesis. The first part of the thesis deals with the defect analysis and the second part of the thesis deals with the statistical degradation rate analysis. In the first part, a detailed analysis on the performance or financial risk related to each defect found in multiple PV power plants across various climatic regions of the USA is presented by assigning a risk priority number (RPN). The RPN for all the defects in each PV plant is determined based on two databases: degradation rate database; defect rate database. In this analysis it is determined that the RPN for each plant is dictated by the technology type (crystalline silicon or thin-film), climate and age. The PV modules aging between 3 and 19 years in four different climates of hot-dry, hot-humid, cold-dry and temperate are investigated in this study.

In the second part, a statistical degradation analysis is performed to determine if the degradation rates are linear or not in the power plants exposed in a hot-dry climate for the crystalline silicon technologies. This linearity degradation analysis is performed using the data obtained through two methods: current-voltage method; metered kWh method. For the current-voltage method, the annual power degradation data of hundreds of individual modules in six crystalline silicon power plants of different ages is used. For the metered kWh method, a residual plot analysis using Winters’ statistical method is performed for two crystalline silicon plants of different ages. The metered kWh data typically consists of the signal and noise components. Smoothers remove the noise component from the data by taking the average of the current and the previous observations. Once this is done, a residual plot analysis of the error component is performed to determine the noise was successfully separated from the data by proving the noise is random.
ContributorsSundarajan, Prasanna (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Rogers, Bradley (Committee member) / Srinivasan, Devarajan (Committee member) / Arizona State University (Publisher)
Created2016
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Description
This is a two-part thesis. Part 1 presents the seasonal and tilt angle dependence of soiling loss factor of photovoltaic (PV) modules over two years for Mesa, Arizona (a desert climatic condition). Part 2 presents the development of an indoor artificial soil deposition chamber replicating natural dew cycle.

This is a two-part thesis. Part 1 presents the seasonal and tilt angle dependence of soiling loss factor of photovoltaic (PV) modules over two years for Mesa, Arizona (a desert climatic condition). Part 2 presents the development of an indoor artificial soil deposition chamber replicating natural dew cycle. Several environmental factors affect the performance of PV systems including soiling. Soiling on PV modules results in a decrease of sunlight reaching the solar cell, thereby reducing the current and power output. Dust particles, air pollution particles, pollen, bird droppings and other industrial airborne particles are some natural sources that cause soiling. The dust particles vary from one location to the other in terms of particle size, color, and chemical composition. The thickness and properties of the soil layer determine the optical path of light through the soil/glass interface. Soil accumulation on the glass surface is also influenced by environmental factors such as dew, wind speeds and rainfall. Studies have shown that soil deposition is closely related to tilt angle and exposure period before a rain event. The first part of this thesis analyzes the reduction in irradiance transmitted to a solar cell through the air/soil/glass in comparison to a clean cell (air/glass interface). A time series representation is used to compare seasonal soiling loss factors for two consecutive years (2014-2016). The effect of tilt angle and rain events on these losses are extensively analyzed. Since soiling is a significant field issue, there is a growing need to address the problem, and several companies have come up with solutions such as anti-soiling coatings, automated cleaning systems etc. To test and validate the effectiveness of these anti-soiling coating technologies, various research institutes around the world are working on the design and development of artificial indoor soiling chambers to replicate the natural process in the field. The second part of this thesis work deals with the design and development of an indoor artificial soiling chamber that replicates natural soil deposition process in the field.
ContributorsVirkar, Shalaim (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Kuitche, Joseph (Committee member) / Arizona State University (Publisher)
Created2017
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Description
Solar photovoltaic (PV) deployment has grown at unprecedented rates since the early 2000s. As the global PV market increases, so will the volume of decommissioned PV panels. Growing PV panel waste presents a new environmental challenge, but also unprecedented opportunities to create value and pursue new economic avenues. Currently, in

Solar photovoltaic (PV) deployment has grown at unprecedented rates since the early 2000s. As the global PV market increases, so will the volume of decommissioned PV panels. Growing PV panel waste presents a new environmental challenge, but also unprecedented opportunities to create value and pursue new economic avenues. Currently, in the United States, there are no regulations for governing the recycling of solar panels and the recycling process varies by the manufacturer. To bring in PV specific recycling regulations, whether the PV panels are toxic to the landfills, is to be determined. Per existing EPA regulations, PV panels are categorized as general waste and are subjected to a toxicity characterization leaching procedure (TCLP) to determine if it contains any toxic metals that can possibly leach into the landfill. In this thesis, a standardized procedure is developed for extracting samples from an end of life PV module. A literature review of the existing regulations in Europe and other countries is done. The sample extraction procedure is tested on a crystalline Si module to validate the method. The extracted samples are sent to an independent TCLP testing lab and the results are obtained. Image processing technique developed at ASU PRL is used to detect the particle size in a broken module and the size of samples sent is confirmed to follow the regulation.
ContributorsKrishnamurthy, Raghav (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Kuitche, Joseph (Committee member) / Arizona State University (Publisher)
Created2017
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Description
Performance of photovoltaic (PV) modules decrease as the operating temperatures increase. In hot climatic conditions, the operating temperature can reach as high as 85°C for the rooftop modules. Considering a typical power drop of 0.5%/°C for crystalline silicon modules, a performance decrease of approximately 30% could be expected during peak

Performance of photovoltaic (PV) modules decrease as the operating temperatures increase. In hot climatic conditions, the operating temperature can reach as high as 85°C for the rooftop modules. Considering a typical power drop of 0.5%/°C for crystalline silicon modules, a performance decrease of approximately 30% could be expected during peak summer seasons due to the difference between module rated temperature of 25°C and operating temperature of 85°C. Therefore, it is critical to accurately predict the temperature of the modules so the performance can be accurately predicted. The module operating temperature is based not only on the ambient and irradiance conditions but is also based on the thermal properties of module packaging materials. One of the key packaging materials that would influence the module operating temperature is the substrate, polymer backsheet or glass. In this study, the thermal influence of three different polymer backsheet substrates and one glass substrate has been investigated through five tasks:

1. Determination and modeling of substrate or module temperature of coupons using four different substrates (three backsheet materials and one glass material).

2. Determination and modeling of cell temperature of coupons using four different substrates (three backsheet materials and one glass material)

3. Determination of temperature difference between cell and individual substrates for coupons of all four substrates

4. Determination of NOCT (nominal operating cell temperature) of coupons using all four substrate materials

5. Comparison of operating temperature difference between backsheet substrate coupons.

All these five tasks have been executed using the specially constructed one-cell coupons with identical cells but with four different substrates. For redundancy, two coupons per substrate were constructed and investigated. This study has attempted to model the effect of thermal conductivity of backsheet material on the cell and backsheet temperatures.
ContributorsNatarajan Rammohan, Balamurali (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Kuitche, Joseph (Committee member) / Arizona State University (Publisher)
Created2017
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Description
Building applied photovoltaics (BAPV) is a major application sector for photovoltaics (PV). Due to the negative temperature coefficient of power output, the performance of a PV module decreases as the temperature of the module increases. In hot climatic conditions, such as the summer in Arizona, the operating temperature of a

Building applied photovoltaics (BAPV) is a major application sector for photovoltaics (PV). Due to the negative temperature coefficient of power output, the performance of a PV module decreases as the temperature of the module increases. In hot climatic conditions, such as the summer in Arizona, the operating temperature of a BAPV module can reach as high as 90°C. Considering a typical 0.5%/°C power drop for crystalline silicon (c-Si) modules, a performance decrease of approximately 30% would be expected during peak summer temperatures due to the difference between rated temperature (25°C) and operating temperature (~90°C) of the modules. Also, in a worst-case scenario, such as partial shading of the PV cells of air gap-free BAPV modules, some of the components could attain temperatures that would be high enough to compromise the safety and functionality requirements of the module and its components. Based on the temperature and weather data collected over a year in Arizona, a mathematical thermal model has been developed and presented in this paper to predict module temperature for five different air gaps (0", 1", 2", 3", and 4"). For comparison, modules with a thermally-insulated (R30) back were evaluated to determine the worst-case scenario. This thesis also provides key technical details related to the specially-built, simulated rooftop structure; the mounting configuration of the PV modules on the rooftop structure; the LabVIEW program that was developed for data acquisition and the MATLAB program for developing the thermal models. In order to address the safety issue, temperature test results (obtained in accordance with IEC 61730-2 and UL 1703 safety standards) are presented and analyzed for nine different components of a PV module, i.e., the front glass, substrate/backsheet (polymer), PV cell, j-box ambient, j-box surface, positive terminal, backsheet inside j-box, field wiring, and diode. The temperature test results obtained for about 140 crystalline silicon modules from a large number of manufacturers who tested modules between 2006 and 2009 at ASU/TÜV-PTL were analyzed and presented in this paper under three test conditions, i.e., short-circuit, open-circuit, and short-circuit and shaded. Also, the nominal operating cell temperatures (NOCTs) of the BAPV modules and insulated-back PV modules are presented in this paper for use by BAPV module designers and installers.
ContributorsOh, Jaewon (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Rogers, Bradley R (Committee member) / Macia, Narciso F. (Committee member) / Arizona State University (Publisher)
Created2010
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Description

Pelvic Circumferential Compression Devices (PCCDs), an important medical device when caring for patients with pelvic fractures, play a crucial role in the stabilization and reduction of the fracture. During pelvic fracture cases, control of internal bleeding through access to the femoral artery is of utmost importance. Current designs of PCCDs

Pelvic Circumferential Compression Devices (PCCDs), an important medical device when caring for patients with pelvic fractures, play a crucial role in the stabilization and reduction of the fracture. During pelvic fracture cases, control of internal bleeding through access to the femoral artery is of utmost importance. Current designs of PCCDs do not allow vital access to this artery and in attempts to gain access, medical professionals and emergency care providers choose to cut into the PCCDs or place them in suboptimal positions with unknown downstream effects. We researched the effects on surface pressure and the overall pressure distribution created by the PCCDs when they are modified or placed incorrectly on the patient. In addition, we investigated the effects of those misuses on pelvic fracture reduction, a key parameter in stabilizing the patient during critical care. We hypothesized that incorrectly placing or modifying the PCCD will result in increased surface pressure and decreased fracture reduction. Our mannequin studies show that for SAM Sling and T-POD, surface pressure increases if a PCCD is incorrectly placed or modified, in support of our hypothesis. However, opposite results occurred for the Pelvic Binder, where the correctly placed PCCD had higher surface pressure when compared to the incorrectly placed or modified PCCD. Additionally, pressure distribution was significantly affected by the modification of the PCCDs. The cadaver lab measurements show that modifying or incorrectly placing the PCCDs significantly limits their ability to reduce the pelvic fracture. These results suggest that while modifying or incorrectly placing PCCDs allows access to the femoral artery, there are potentially dangerous effects to the patient including increased surface pressures and limited fracture reduction.

ContributorsRyder, Madison Taylor (Co-author) / Conley, Ian (Co-author) / Vernon, Brent (Thesis director) / Bogert, James (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Pelvic Circumferential Compression Devices (PCCDs), an important medical device when caring for patients with pelvic fractures, play a crucial role in the stabilization and reduction of the fracture. During pelvic fracture cases, control of internal bleeding through access to the femoral artery is of utmost importance. Current designs of PCCDs

Pelvic Circumferential Compression Devices (PCCDs), an important medical device when caring for patients with pelvic fractures, play a crucial role in the stabilization and reduction of the fracture. During pelvic fracture cases, control of internal bleeding through access to the femoral artery is of utmost importance. Current designs of PCCDs do not allow vital access to this artery and in attempts to gain access, medical professionals and emergency care providers choose to cut into the PCCDs or place them in suboptimal positions with unknown downstream effects. We researched the effects on surface pressure and the overall pressure distribution created by the PCCDs when they are modified or placed incorrectly on the patient. In addition, we investigated the effects of those misuses on pelvic fracture reduction, a key parameter in stabilizing the patient during critical care. We hypothesized that incorrectly placing or modifying the PCCD will result in increased surface pressure and decreased fracture reduction. Our mannequin studies show that for SAM Sling and T-POD, surface pressure increases if a PCCD is incorrectly placed or modified, in support of our hypothesis. However, opposite results occurred for the Pelvic Binder, where the correctly placed PCCD had higher surface pressure when compared to the incorrectly placed or modified PCCD. Additionally, pressure distribution was significantly affected by the modification of the PCCDs. The cadaver lab measurements show that modifying or incorrectly placing the PCCDs significantly limits their ability to reduce the pelvic fracture. These results suggest that while modifying or incorrectly placing PCCDs allows access to the femoral artery, there are potentially dangerous effects to the patient including increased surface pressures and limited fracture reduction.

ContributorsConley, Ian Patrick (Co-author) / Ryder, Madison (Co-author) / Vernon, Brent (Thesis director) / Bogert, James (Committee member) / Harrington Bioengineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

Protein and gene circuit level synthetic bioengineering can require years to develop a single target. Phage assisted continuous evolution (PACE) is a powerful new tool for rapidly engineering new genes and proteins, but the method requires an automated cell culture system, making it inaccessible to non industrial research programs. Complex

Protein and gene circuit level synthetic bioengineering can require years to develop a single target. Phage assisted continuous evolution (PACE) is a powerful new tool for rapidly engineering new genes and proteins, but the method requires an automated cell culture system, making it inaccessible to non industrial research programs. Complex protein functions, like specific binding, require similarly dynamic PACE selection that can be alternatively induced or suppressed, with heat labile chemicals like tetracycline. Selection conditions must be controlled continuously over days, with adjustments made every few minutes. To make PACE experiments accessible to the broader community, we designed dedicated cell culture hardware and integrated optogenetically controlled plasmids. The low cost and open source platform allows a user to conduct PACE with continuous monitoring and precise control of evolution using light.

ContributorsTse, Ashley (Author) / Bartelle, Benjamin (Thesis director) / Tian, Xiaojun (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor) / School of International Letters and Cultures (Contributor) / Harrington Bioengineering Program (Contributor)
Created2023-05
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Description
Solar photovoltaic (PV) generation has seen significant growth in 2021, with an increase of around 22% and exceeding 1000 TWh. However, this has also led to reliability and durability issues, particularly potential induced degradation (PID), which can reduce module output by up to 30%. This study uses cell- and module-level

Solar photovoltaic (PV) generation has seen significant growth in 2021, with an increase of around 22% and exceeding 1000 TWh. However, this has also led to reliability and durability issues, particularly potential induced degradation (PID), which can reduce module output by up to 30%. This study uses cell- and module-level analysis to investigate the impact of superstrate, encapsulant, and substrate on PID.The influence of different substrates and encapsulants is studied using one-cell modules, showing that substrates with poor water-blocking properties can worsen PID, and encapsulants with lower volumetric resistance can conduct easily under damp conditions, enabling PID mechanisms (results show maximum degradation of 9%). Applying an anti-soiling coating on the front glass (superstrate) reduces PID by nearly 53%. Typical superstrates have sodium which accelerates the PID process, and therefore, using such coatings can lessen the PID problem. At the module level, the study examines the influence of weakened interface adhesion strengths in traditional Glass-Backsheet (GB) and emerging Glass-Glass (GG) (primarily bifacial modules) constructions. The findings show nearly 64% more power degradation in GG modules than in GB. Moreover, the current methods for detecting PID use new modules, which can give inaccurate information instead of DH-stressed modules for PID testing, as done in this work. A comprehensive PID susceptibility analysis for multiple fresh bifacial constructions shows significant degradation from 20 to 50% in various constructions. The presence of glass as the substrate exacerbates the PID problem due to more ionic activity available from the two glass sides. Recovery experiments are also conducted to understand the extent of the PID issue. Overall, this study identifies, studies, and explains the impact of superstrate, substrate, and encapsulant on the underlying PID mechanisms. Various pre- and post-stress characterization tests, including light and dark current-voltage (I-V) tests, electroluminescence (EL) imaging, infrared (IR) imaging, and UV fluorescence (UVF) imaging, are used to evaluate the findings. This study is significant as it provides insights into the PID issues in solar PV systems, which can help improve their performance and reliability.
ContributorsMahmood, Farrukh ibne (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Rogers, Bradley (Committee member) / Oh, Jaewon (Committee member) / Rajadas, John (Committee member) / Arizona State University (Publisher)
Created2023
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Description

Following a study conducted in 1991 supporting that kinesthetic information affects visual processing information when moving an arm in extrapersonal space, this research aims to suggest utilizing virtual-reality (VR) technology will lead to more accurate and faster data acquisition (Helms Tillery, et al.) [1]. The previous methods for conducting such

Following a study conducted in 1991 supporting that kinesthetic information affects visual processing information when moving an arm in extrapersonal space, this research aims to suggest utilizing virtual-reality (VR) technology will lead to more accurate and faster data acquisition (Helms Tillery, et al.) [1]. The previous methods for conducting such research used ultrasonic systems of ultrasound emitters and microphones to track distance from the speed of sound. This method made the experimentation process long and spatial data difficult to synthesize. The purpose of this paper is to show the progress I have made in the efforts to capture spatial data using VR technology to enhance the previous research that has been done in the field of neuroscience. The experimental setup was completed using the Oculus Quest 2 VR headset and included hand controllers. The experiment simulation was created using Unity game engine to build a 3D VR world which can be used interactively with the Oculus. The result of this simulation allows the user to interact with a ball in the VR environment without seeing the body of the user. The VR simulation is able to be used in combination with real-time motion capture cameras to capture live spatial data of the user during trials, though spatial data from the VR environment has not been able to be collected.

ContributorsSyed, Anisa (Author) / Helms-Tillery, Stephen (Thesis director) / Tanner, Justin (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2022-05