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- Creators: Tamizhmani, Govindasamy
Description
Photovoltaic (PV) systems are one of the next generation's renewable energy sources for our world energy demand. PV modules are highly reliable. However, in polluted environments, over time, they will collect grime and dust. There are also limited field data studies about soiling losses on PV modules. The study showed how important it is to investigate the effect of tilt angle on soiling. The study includes two sets of mini-modules. Each set has 9 PV modules tilted at 0, 5, 10, 15, 20, 23, 30, 33 and 40°. The first set called "Cleaned" was cleaned every other day. The second set called "Soiled" was never cleaned after the first day. The short circuit current, a measure of irradiance, and module temperature was monitored and recorded every two minutes over three months (January-March 2011). The data were analyzed to investigate the effect of tilt angle on daily and monthly soiling, and hence transmitted solar insolation and energy production by PV modules. The study shows that during the period of January through March 2011 there was an average loss due to soiling of approximately 2.02% for 0° tilt angle. Modules at tilt anlges 23° and 33° also have some insolation losses but do not come close to the module at 0° tilt angle. Tilt anlge 23° has approximately 1.05% monthly insolation loss, and 33° tilt angle has an insolation loss of approximately 0.96%. The soiling effect is present at any tilt angle, but the magnitude is evident: the flatter the solar module is placed the more energy it will lose.
ContributorsCano Valero, José (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Madakannan, Arunachalanadar (Committee member) / Macia, Narciso (Committee member) / Arizona State University (Publisher)
Created2011
Description
The object of this study was a 26 year old residential Photovoltaic (PV) monocrystalline silicon (c-Si) power plant, called Solar One, built by developer John F. Long in Phoenix, Arizona (a hot-dry field condition). The task for Arizona State University Photovoltaic Reliability Laboratory (ASU-PRL) graduate students was to evaluate the power plant through visual inspection, electrical performance, and infrared thermography. The purpose of this evaluation was to measure and understand the extent of degradation to the system along with the identification of the failure modes in this hot-dry climatic condition. This 4000 module bipolar system was originally installed with a 200 kW DC output of PV array (17 degree fixed tilt) and an AC output of 175 kVA. The system was shown to degrade approximately at a rate of 2.3% per year with no apparent potential induced degradation (PID) effect. The power plant is made of two arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the north array and the other thesis presents the results obtained on the south array. The resulting study showed that PV module design, array configuration, vandalism, installation methods and Arizona environmental conditions have had an effect on this system's longevity and reliability. Ultimately, encapsulation browning, higher series resistance (potentially due to solder bond fatigue) and non-cell interconnect ribbon breakages outside the modules were determined to be the primary causes for the power loss.
ContributorsBelmont, Jonathan (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Henderson, Mark (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2013
Description
Potential induced degradation (PID) due to high system voltages is one of the major degradation mechanisms in photovoltaic (PV) modules, adversely affecting their performance due to the combined effects of the following factors: system voltage, superstrate/glass surface conductivity, encapsulant conductivity, silicon nitride anti-reflection coating property and interface property (glass/encapsulant; encapsulant/cell; encapsulant/backsheet). Previous studies carried out at ASU's Photovoltaic Reliability Laboratory (ASU-PRL) showed that only negative voltage bias (positive grounded systems) adversely affects the performance of commonly available crystalline silicon modules. In previous studies, the surface conductivity of the glass surface was obtained using either conductive carbon layer extending from the glass surface to the frame or humidity inside an environmental chamber. This thesis investigates the influence of glass surface conductivity disruption on PV modules. In this study, conductive carbon was applied only on the module's glass surface without extending to the frame and the surface conductivity was disrupted (no carbon layer) at 2cm distance from the periphery of frame inner edges. This study was carried out under dry heat at two different temperatures (60 °C and 85 °C) and three different negative bias voltages (-300V, -400V, and -600V). To replicate closeness to the field conditions, half of the selected modules were pre-stressed under damp heat for 1000 hours (DH 1000) and the remaining half under 200 hours of thermal cycling (TC 200). When the surface continuity was disrupted by maintaining a 2 cm gap from the frame to the edge of the conductive layer, as demonstrated in this study, the degradation was found to be absent or negligibly small even after 35 hours of negative bias at elevated temperatures. This preliminary study appears to indicate that the modules could become immune to PID losses if the continuity of the glass surface conductivity is disrupted at the inside boundary of the frame. The surface conductivity of the glass, due to water layer formation in a humid condition, close to the frame could be disrupted just by applying a water repelling (hydrophobic) but high transmittance surface coating (such as Teflon) or modifying the frame/glass edges with water repellent properties.
ContributorsTatapudi, Sai Ravi Vasista (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2012
Description
This focuses on recent changes in Arizona eminent domain law regarding the question of whether a use be "truly public." In light of the landmark decision in Bailey v City of Mesa--often lauded as a great victory for proponents of private property rights-- a few sources will be reviewed to provide an indication of the extent redevelopment in Arizona has been affected by the decision. While the result in Bailey, precluding the City from taking the subject property may have been the correct outcome, the test to which the case now subjects any similar case involving redevelopment has made it unnecessarily difficult for political subdivisions of the state to carry out legislated redevelopment goals. The Bailey case only served to convolute the question of "public use" in the context of economic development, rather than create a workable body of law. In addition to providing a historical context and analyzing the effect of new interpretations on redevelopment generally, this paper will critique the Bailey decision in order to resolve the conflict that the decision created: that of the redevelopment goals of the state and municipalities and the authorized use of condemnation to achieve these goals with the judiciary's decision to greatly restrict the use of condemnation for the achievement of redevelopment goals. Arguably this conflict arose from a failure to fully understand the complexities of the use of the power of eminent domain for redevelopment purposes. Unaware of the need to use eminent domain in order to speed along and make possible economic redevelopment, overzealous proponents of property rights have reduced the issue to a narrow view of the state vs. the individual. Hopefully this paper can offer a more moderate and unbiased view of the use of eminent domain in light of the charge of the state and municipalities to facilitate economic growth.
ContributorsStern-Sapad, Zalman Badi (Author) / Birnbaum, Gary (Thesis director) / Braselton, James (Committee member) / Barrett, The Honors College (Contributor) / W. P. Carey School of Business (Contributor)
Created2015-05
Description
Abstract I sought out a project that would be able to intertwine the topics of business law and the business of sports. After reading and researching a few different options, one combination of law and sports that stood out to me was the frequent labor disputes between NHL owners and the players' union. The main goal of this project was to examine whether or not the lockouts that were instituted by National Hockey League owners during the labor disputes that occurred in 2004 and 2012 actually left the league with a better long term financial and social landscape. Through the examination of the stakeholders that were involved in each dispute and their resulting situations, I presented my answer to the above question. In order to properly study the overall situation, I also discussed the history of sports business, the history of the National Hockey League's business landscape, and collective bargaining in sports amongst other topics.
ContributorsNix, Eric Anthony (Author) / Eaton, John (Thesis director) / Kutz, Elana (Committee member) / Barrett, The Honors College (Contributor) / Department of Marketing (Contributor) / W. P. Carey School of Business (Contributor)
Created2015-05
Description
This thesis will focus on the organizational structures and leadership challenges within private law firms. It begins by explaining the different roles within the organizational structure. It will then discuss various other duties that are carried out by lawyers in addition to legal work. Through the use of qualitative methodology, including a review of scholarly literature and semi-formal interviews with private firm partners, this research mainly focuses on the challenges that exist in private law firms. The study concludes with possible solutions to address the discussed challenges in private law firms.
ContributorsKrikorian, Dikranouhi (Author) / Trujillo, Rhett (Thesis director) / Waldman, David (Committee member) / Barrett, The Honors College (Contributor) / W. P. Carey School of Business (Contributor) / Department of Management (Contributor)
Created2015-05
Description
Certain laws relating to self-defense were created known as "Stand Your Ground" laws. The public has interpreted these laws in ways that expand them beyond their original scope. To gain an understanding of self-defense laws, a look at the origins of self-defense is needed. Following the historical background, several cases will be examined that illustrate how the public has interpreted "Stand Your Ground" laws, and how these interpretations clash with elements of self-defense. Several philosophical principles including natural rights, the social contract, and some form of utilitarianism, will be discussed in relation to "Stand Your Ground" laws. A possible conclusion can be drawn that by misinterpreting "Stand Your Ground" laws, people compromise the philosophical ideals they hold, and infringe on other people's natural rights, break the social contract, and create societal unhappiness. Finally, some people are calling for reform of "Stand Your Ground" laws. These reforms focus on correcting public perception of "Stand Your Ground" laws.
ContributorsSmith, Geramya Joseph (Author) / Sigler, Mary (Thesis director) / Stanford, Michael (Committee member) / Kader, David (Committee member) / Barrett, The Honors College (Contributor) / Sandra Day O'Connor College of Law (Contributor) / W. P. Carey School of Business (Contributor)
Created2013-05
Description
Volume depletion can lead to migraines, dizziness, and significant decreases in a subject's ability to physically perform. A major cause of volume depletion is dehydration, or loss in fluids due to an imbalance in fluid intake to fluid excretion. Because proper levels of hydration are necessary in order to maintain both short and long term health, the ability to monitor hydration levels is growing in clinical demand. Although devices capable of monitoring hydration level exist, these devices are expensive, invasive, or inaccurate and do not offer a continuous mode of measurement. The ideal hydration monitor for consumer use needs to be characterized by its portability, affordability, and accuracy. Also, this device would need to be noninvasive and offer continuous hydration monitoring in order to accurately assess fluctuations in hydration data throughout a specified time period. One particular method for hydration monitoring that fits the majority of these criteria is known as bioelectric impedance analysis (BIA). Although current devices using BIA do not provide acceptable levels of accuracy, portability, or continuity in data collection, BIA could potentially be modified to fit many, if not all, desired customer specifications. The analysis presented here assesses the viability of using BIA as a new standard in hydration level measurement. The analysis uses data collected from 22 subjects using an existing device that employs BIA. A regression derived for estimating TBW based on the parameters of age, weight, height, sex, and impedance is presented. Using impedance data collected for each subject, a regression was also derived for estimating impedance based on the factors of age, weight, height, and sex. The derived regression was then used to calculate a new impedance value for each subject, and these new impedance values were used to estimate TBW. Through a paired-t test between the TBW values derived by using the direct measurements versus the calculated measurements of impedance, the two samples were found to be comparable. Considerations for BIA as a noninvasive measurement of hydration are discussed.
ContributorsTenorio, Jorge Antonio (Author) / LaBelle, Jeffrey (Thesis director) / Pizziconi, Vincent (Committee member) / Spano, Mark (Committee member) / Barrett, The Honors College (Contributor) / W. P. Carey School of Business (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
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 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
Description
Modern Americans ignorantly live under a blanket of unread terms, conditions, and binding contracts. Often, these contracts (mostly associated with products and services) come and go with little effect. Periodically, the products or services cause the consumer harm, leading them to seek repair. The consumer then realizes that all the fine print they failed to read makes an impactful legal difference. This paper analyzes the work of Professor Radin through her book, Boilerplate. It goes on to explore many other arguments presented by contract theorists and makes substantial claims regarding the dangers of boilerplate (unread terms and conditions).
ContributorsBecker, Alexander Daniel (Author) / Koretz, Lora (Thesis director) / Calleros, Charles (Committee member) / Barrett, The Honors College (Contributor) / W. P. Carey School of Business (Contributor) / Department of English (Contributor)
Created2015-05