The current impetus for alternative energy sources is increasing the demand for solar energy technologies in Florida – the Sunshine State. Florida’s energy production from solar, thermal or photovoltaic sources accounts for only 0.005% of the state total energy generation. The existing types of technologies, methods of installation, and mounting locations for solar panels vary significantly, and are consequently affected by wind loads in different ways. The fact that Florida is frequently under hurricane risk and the lack of information related with design wind loads on solar panels result in a limited use of solar panels for generating energy in the “Sunshine State” Florida. By using Boundary Layer Wind Tunnel testing techniques, the present study evaluates the effects of wind on solar panels, and provides explicit and reliable information on design wind loads in the form of pressure coefficient value. The study considered two different types of solar panel arrangements, (1) isolated solar panel and (2) arrays, and two different mounting locations, (1) ground mounted and (2) roof mounted. Detailed wind load information was produced as part of this study for isolated and arrayed solar panels. Two main conclusions from this study are the following:(1) for isolated solar panel with high slopes the wind load for wind angle of attack (AoA) perpendicular to the main axis exhibited the largest wind loads; (2) for arrays, while the outer rows and column were subjected to high wind loads for AoA perpendicular to the main axis, the interior solar panels were subjected to higher loads for oblique AoA.

Orientador: Jose Ellis Ripper Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-15T09:17:05Z (GMT). No. of bitstreams: 1 Rego_AntonioCarlosGravatoBordeaux_M.pdf: 1540230 bytes, checksum: 281e609045d15f5336b1936fe7d0049f (MD5) Previous issue date: 1977 / Resumo: Não informado / Abstract: Not informed. / Mestrado / Física / Mestre em Física

Orientador: Jorge E. Quintero Pinto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos e Agricola / Made available in DSpace on 2018-07-16T22:13:03Z (GMT). No. of bitstreams: 1 Santos_LuizAlbertodos_M.pdf: 9789379 bytes, checksum: 2161a4eb1a0306852cdb90e4682b1176 (MD5) Previous issue date: 1980 / Resumo: Construiu-se, com materiais de baixo custo e facilmente encontrados no mercado, tais como I tijolos, pedra britada, madeira e plástico, um coletor solar de 60 m2(3 m de largura por 20 m de comprimento), contendo um leito de pedras capaz de funcionar como armazenador de energia. O coletor solar foi empregado para aquecer o ar ambiente que, por sua vez, foi utilizado para secar, até o teor de 12%, base úmida, cinquenta e cinco toneladas de soja "Santa Rosa", com teor inicial médio de umidade de 17,2%, base úmida, contidas num silo metálico. Fez-se a avaliação matemática do coletor solar utilizando-se, para isso, um modelo baseado nos princípios da transferência de calor. O modelo empregado simulou, com precisão, os resultados experimentais da temperatura do ar na saída do coletor solar podendo, pois, ser utilizado para projetar novos coletores em 10 locais diferentes de onde se realizou o experimento. Determinou-se, posteriormente, o acréscimo de temperatura que deveria ser fornecido ao ar ambiente em diferentes condições atmosféricas, para que este ar, quando em contato com sementes de soja ou soja industrial com teor inicial de umidade de 18% ou de 20% base úmida, secasse o produto até 12%, base úmida. A vazão de ar necessário à secagem dos produtos em questão foram obtidas dos trabalhos de Villa et. al., 1978. De posse das vazões de ar e dos incrementos de temperatura, foram realizadas simulações das áreas coletoras, necessárias para aquecer a referida vazão de ar do incremento de temperatura em questão. Foram efetuados cálculos das áreas dos coletores plano e armazenador, necessárias para aquecer de 5ºC, diferentes vazoes de ar em três nIveis distintos de radiação solar. Estudou-se a influência da vazão de ar e da temperatura ambiente na eficiência do coletor armazenador para três níveis de radiação solar / Abstract: It was built with materials from low-cost and readily available in the market, I like bricks, crushed stone, wood and plastic, a solar collector of 60 m2 (3 m wide by 20 meters in length), containing a bed of stones able to function as storage of energy. The solar collector was used to heat the air which, in turn, was used for drying up the level of 12%, wet basis, fifty-five tons of soybeans "Santa Rosa", with an average initial moisture content of 17 , 2%, wet basis, contained in a metal silo. There was a mathematical evaluation of solar collector was used for this, a model based on the principles of heat transfer. The simulated model employee, accurately, the experimental results of air temperature in the output of solar collector can thus be used to design new collectors in 10 different locations from where the experiment took place. It was determined subsequently, the increase in temperature which should be provided to the ambient air in different weather conditions, so that this air, when in contact with soya beans or soya industry with initial moisture content of 18% or 20% wet basis, secasse the product by 12%, wet basis. The flow of air needed for drying of the products in question were obtained from the work of Villa et. al., 1978. With the flow of air and increases in temperature, were performed simulations of collecting areas, needed to heat the air that flow from the increase in temperature in question. Calculations were done in the areas of collectors and storage plan, needed to warm up to 5 C, different flow of air into three distinct levels of solar radiation. The influence of the flow of air and the ambient temperature in the collector efficiency of storage for three levels of solar radiation / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

Orientador : Isaias de Carvalho Macedo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Campinas / Made available in DSpace on 2018-07-17T22:35:54Z (GMT). No. of bitstreams: 1 Franca_FernandodeAlmeida_M.pdf: 1042869 bytes, checksum: 29b623b207ec17f21ebf1679a85b6b0f (MD5) Previous issue date: 1979 / Resumo: Análise do desempeho térmico instantâneo de coletores de parábola composta - coletor de "Winston" - de baixa concentração, para três montagens: cobertura de vidro no plano de abertura e refletor isolado; cobertura de vidro no plano de abertura e refletor sem isolamento e cobertura de vidro imediatamenete acima do absorvedor. A transferência de calor convectiva no interior do coletor, 2a montagem, foi determinada experimentalmente. São discutidas as técnicas de construção de protótipos de concentrações 2,4 e 5,3 e apresentadas as curvas de eficiências, teóricas e experimentais, para temperaturas do absorvedor variando entre 50ºC e 150°C / Abstract: Not informed / Mestrado / Mestre em Engenharia Mecânica

Bibliography: pages 98-103. / The thesis presented is a study of the absorption characteristics of diffusely and specularly reflecting V-grooved surfaces. Concepts are developed for the so-called "apparent" absorptance of a V-groove cavity, as well as for the "effective" absorptance of a V-grooved surface. These concepts are formulated in closed form mathematical equations, which facilitate both the optimization of V-grooved surfaces and their engineering design. In order to verify the theoretical analysis, experiments are carried out on 34 V-grooved brass specimens. In addition, the experiments are meant to provide information about the behaviour of such surfaces used for solar energy collection. For that purpose, the specimens are exposed to simulated sunlight, and their effective absorptances, as well as their absorption efficiencies, are determined by a calorimetric method. The highlights among the results are: 1. V-grooves - carefully optimized and applied to a solar energy absorbing surface - can raise its absorptance almost to unity and improve its absorption efficiency. 2. Best performances at elevated temperatures can be expected from using metal surfaces which are provided with specular V-grooves having a small groove angle (< 30⁰). 3. The optimal groove angle is dependent on (1) the reflection properties of the surface, (2) the absorptance of the surface material, and (3) the ratio of groove depth to width of land which occurs between grooves.

This thesis is dedicated to developing conjugated polymer and small-molecule donor materials for solution-processable organic solar cells. To begin with, a brief introduction of organic solar cells (OSCs) and an overview of donor materials development were presented in Chapter 1. In chapter 2, we used carbon-carbon triple bands as linkage of the TVT unit to develop a new building block, ATVTA. Small molecules S-03, S-04, and S-05 with ATVTA as building block showed broad absorption spectra and low-lying HOMO energy levels. S-01 with TVT unit and S-02 with AT2 as building block were also synthesized for clear comparison. OSCs devices based on S-01 and S-02 showed a Voc of 0.88 V and 0.89 V, respectively. The device based on S-03 exhibited a high Voc of 0.96 V, leading to a PCE of 2.19%. The devices based on S-04 and S-05 afforded a notable Voc over 1.0 V. The results demonstrate that ATVTA unit is a promising building block for extending π conjugation of the molecules without pulling up their HOMO energy levels. Chapter 3 focused on the development of 2D-conjugated small-molecule donor materials. The 2D-conjugated small molecule S-06 possesses excellent solution processability, broad absorption feature, respectable hole mobility and good film-forming morphology. The conjugated thiophene side chain not only effectively extends the absorption spectrum, but also lowers the HOMO energy level, which is desirable for obtaining high Voc. The BHJ OSCs based on S-06:PC70BM (1:0.5, w/w) afforded a high PCE of 4.0% and a notable FF of 0.63 without any special treatment needed. This preliminary work demonstrates that this kind of 2D-conjugated small molecules offer a good strategy to design new photovoltaic small molecule-based donor materials with high FF and Voc for high-efficiency OSCs. The consistently developed two 2D-conjugated small molecules S-07 and S-08 also possess low-lying HOMO energy levels. OSC device based on S-07:PC60BM (1:3, w/w) afforded a notable Voc of 0.96 V, with a PCE of 2.52%. BHJ devices based on S-08 will be fabricated and tested to investigate its photovoltaic properties in the near future. We developed a series of oligothiophenes with platinum(Ⅱ) as the building block in Chapter 4. These small metallated conjugated small molecules exhibited broad spectra and relatively low-lying HOMO energy levels in the range of –5.27 eV to –5.40 eV. Introducing platinum(Ⅱ) arylene ethynylenes as building block can be considered as an approach to obtain small-molecule donors with satisfactory absorption features and HOMO energy levels. Nevertheless, due to the low FF, the PCEs of these donor materials based devices are lower than 2%. Fine tuning the film morphologies of this kind of metallated small-molecule donor materials should be carried out to improve their photovoltaic performance. We addressed an efficient approach to improve the photovoltaic properties by side chain engineering in 2D-conjugated polymers in Chapter 5. Considering the fact that the Voc of PBDTTT based devices is less than 0.8 V, we introduced alkylthio substituent on the conjugated thiophene side chains of the 2D-conjugated copolymer to further improve the photovoltaic performance of the 2D-conjugated copolymers PBDTTTs. The weak electron-donating ability of the alkylthio side chains effectively down-shifted the HOMO energy level of PBDTT-S-TT by 0.11 eV in comparison to the corresponding polymer with alkyl substitution on the conjugated thiophene side chains. The PSC device based on PBDTT-S-TT showed an enhanced Voc of 0.84 V, which is among the highest one in the reported copolymers based on BDT and TT units, leading to an enhanced PCE of 8.42%. The results indicate that molecular modification by introducing alkylthio side chain will be a promising strategy to broaden the absorption, down-shift the HOMO energy level and increase the hole mobility of the low band gap 2D-conjugated polymers for further enhancing the photovoltaic performance of PSCs. PBDTT-O-TT-C and PBDTT-S-TT-C were developed to further study the conclusion. We found that OSC device based on PBDTT-S-TT-C with alkylthio side chain also demonstrated a high Voc of 0.89 V, with a PCE of 6.85% when processed with 3% DIO additive

abstract: Solar energy as a limitless source of energy all around the globe has been difficult to harness. This is due to the low direct solar-electric conversion efficiency which has an upper limit set to the Shockley-Queisser limit. Solar thermophotovoltaics (STPV) is a much more efficient solar energy harvesting technology as it has the potential to overcome the Shockley-Queisser limit, by converting the broad-spectrum solar irradiation into narrowband infrared spectrum radiation matched to the PV cell. Despite the potential to surpass the Shockley-Queisser limit, very few experimental results have reported high system-level efficiency. The objective of the thesis is to study the STPV conversion performance with selective metafilm absorber and emitter paired with a commercial GaSb cell at different solar concentrations. Absorber and Emitter metafilm thickness was optimized and fabricated. The optical properties of fabricated metafilms showed good agreement with the theoretically determined properties. The experimental setup was completed and validated by measuring the heat transfer rate across the test setup and comparing it with theoretical calculations. A novel method for maintaining the gap between the emitter and PV cell was developed using glass microspheres. Theoretical calculations show that the use of the glass of microspheres introduces negligible conduction loss across the gap compared to the radiation heat transfer, which is confirmed by experimental heat transfer measurement. This research work will help enhance the fundamental understanding and the development of the high-efficiency solar thermophotovoltaic system. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2020

Bulk heterojunction (BHJ) devices represent a very versatile family of organic cells for both the fields of solar energy conversion and photodetection. Organic photovoltaics (OPV) are an attractive alternative to their silicon-based counterparts because of their potential for low-cost roll-to-roll printing, and their intended application in light-weight mechanically conformable devices and in window-type semi-transparent PV modules. Of all proposed OPV candidates, polymer donor with different absorption range are especially promising when used in conjunction with complementary absorbing acceptor materials, like fullerene derivatives (PCBM), conjugated molecules or polymers, achieving nowadays power conversion efficiencies (PCEs) in the range of 10-13% and being a step closer to practical applications. Among the photodetectors (PD), low band gap polymer blended with PCBM decked out the attention, given their extraordinary range of detection from UV to IR and high detectivity values reached so far, compared to the inorganic devices. Since the research has been focused on the enhancement of those numbers for an effective commercialization of organic cells, the topic of the following thesis has been centered on the synthesis of different polymer structures with diverse absorption ranges, used as donor or acceptor, with emphasis on performance in various BHJ devices either for solar cells and photodetectors. In the first part, two new wide band gap polymers, used as donor material in BHJ devices blended with fullerene and small molecule acceptors, are presented. The PBDT_2FT and PBDTT_2FT have shown nice efficiencies from 7% to 9.8%. The device results are implemented with a morphology study and a specific application in a semi-transparent tandem device, reaching a record PCE of 5.4% for average level of transparency of 48%. In another section two new low band gap polymers (Eopt~ 1.26 eV) named DTP_2FBT and (Eopt~ 1.1 eV) named BDTT_BTQ are presented. While the DTP based one resulted to be an optimal candidate for future tandem solar cell application, the other one has been applied for a competitive PD. At last, a comparative study displaying two new acceptor polymers based on modified Isoindigo motifs named PIID(CO)_2FT and PIID(CO)_BTIA brought some prospective for future investigations on fullerene free OSC.

The phenomenon of a total solar eclipse has captivated human beings for millennium, often stirring a unique spiritual experience within its viewers. Witnesses claim to be intensely moved by the occurrence, and many contemporary “eclipse chasers” constantly travel across the globe to engulf themselves in the euphoric moments of totality. Before the advent of modern technology, both lunar and solar eclipses alike were quite terrifying, as they occurred unexpectedly and without warning. Eclipses induced fear rather than awe and wonder. Now that we possess the equipment to accurately track the Moon, Sun, and Earth, astronomers can pinpoint past eclipses as well as predict them far into the future. In fact, this practice has become so accurate that the date of Christ’s Crucifixion is estimated to have fallen on Friday, April 3, 33 AD1. Now that frightfulness has been removed from the equation, eclipses stand to provide an awe-inspiring as well as unifying experience. Just recently, the United States buzzed with collective anticipation; the total solar eclipse of August 21, 2017 cast a deep shadow from coast to coast2. Even those not the in the path of totality took time out of their day to witness a partial eclipse. Schoolchildren and adults alike came together to see these three celestial bodies align with magnificence. While a solar eclipse is a beautiful occurrence, spectators must take precautions to prevent permanent eye damage or blindness. The younger portion of the population is likely to have never experienced such a thing, thus there is a clear demand for education on safe eclipse viewing practices3. In reconciling the unique psychological effects, physical limitations, and dangers associated with watching a solar eclipse, architecture as a collection of geographical and spatial resources will offer a unique setting for eclipse anticipation and totality. The challenge to such a proposal lies in the paradoxical frequency of solar eclipses. A physical response thus requires a combination of mobile and stationary elements. Temporary vessels will be deployed in several locations as the schedule of future eclipses unfolds. Static structures and inscriptions scored into the earth serve as a memorial to the fleeting event, allowing the architecture to educate beyond the lifespan of the eclipse. These interventions serve to impress upon the occupant the enormity of such a celestial alignment. / 0 / SPK / archives@tulane.edu

The optimization of photovoltaic (PV) power generation system requires an accurate system performance model capable of validating the PV system optimization design. Currently, many commercial PV system modeling programs are available, but those programs are not able to model PV systems on a distorted ground level. Furthermore, they were not designed to optimize PV systems that are already installed. To solve these types of problems, this thesis proposes an optimization method using model simulations and a MATLAB-based PV system performance model. The optimization method is particularly designed to address partial shading issues often encountered in PV system installed on distorted ground. The MATLAB-based model was validated using the data collected from the Cal Poly Gold Tree Solar Field. It was able to predict the system performance with 96.4 to 99.6 percent accuracy. The optimization method utilizes the backtracking algorithm already installed in the system and the pitch distance to control the angle of the tracker and reduces solar panels partial shading on the adjacent row to improve system output. With pitch distances reduced in the backtracking algorithm between 2.5 meters and 3 meters, the inverter with inter-row shading can expect a 10.4 percent to 28.9 percent increase in power production. The implementation and calibration of this optimization method in the field this spring was delayed due to COVID-19. The field implementation is now expected to start this summer.