Solar PV Powered Air Conditioner Analysis for an Office/Classroom in a Tropical Climate

This thesis focuses on using photovoltaic produced electricity to power air conditioners in a tropical climate. The study takes place in Surabaya, Indonesia at two different locations the classroom, located at the UBAYA campus and the home office, 10 km away. Indonesia has an average solar irradiation of about 4.8 kWh/m²/day (PWC Indonesia, 2013) which is for ideal conditions for these tests. At the home office, tests were conducted on different photovoltaic systems. A series of measuring devices recorded the performance of the 800 W PV system and the consumption of the 1.35 kW air conditioner (cooling capacity). To have an off grid system many of the components need to be oversized. The inverter has to be oversized to meet the startup load of the air conditioner, which can be 3 to 8 times the operating power (Rozenblat, 2013). High energy consumption of the air conditioner would require a large battery storage to provide one day of autonomy. The PV systems output must at least match the consumption of the air conditioner. A grid connect system provides a much better solution with the 800 W PV system providing 80 % of the 3.5 kWh load of the air conditioner, the other 20 % coming from the grid during periods of low irradiation. In this system the startup load is provided by the grid so the inverter does not need to be oversized. With the grid-connected system, the PV panel’s production does not need to match the consumption of the air conditioner, although a smaller PV array will mean a smaller percentage of the load will be covered by PV. Using the results from the home office tests and results from measurements made in the classroom. Two different PV systems (8 kW and 12 kW) were simulated to power both the current air conditioners (COP 2.78) and new air conditioners (COP 4.0). The payback period of the systems can vary greatly depending on if a feed in tariff is awarded or not. If the feed in tariff is awarded the best system is the 12 kW system, with a payback period of 4.3 years and a levelized cost of energy at -3,334 IDR/kWh. If the feed in tariff is not granted then the 8 kW system is the best choice with a lower payback period and lower levelized cost of energy than the 12 kW system under the same conditions.

Gulf of Mexico's Offshore Oil Platform Wind Potential

There are over 6000 natural resource drilling platforms in the Gulf of Mexico, all of which will become obsolete once their deposits are extracted. This study examined one of the possible alternate uses for these platforms, wind power potential. Using ArcGIS the number of platforms was reduced by weighting their distance from National Data Buoy Center wind speed collection points and water depth. Calculations were done to assess the optimal sites remaining, as well as provide an estimate of the energy potential for each site. Data for this project was obtained from the Minerals Management Service (MMS), United States Geological Service (USGS), and National Data Buoy Center (NDBC). A major limitation of this project was a lack of NDBC wind speed buoys, creating large data gaps and excluding many oil rigs that have otherwise high energy potential.

Eficientização energética em prédios públicos: um desafio aos gestores municipais frente aos requisitos de governança e sustentabilidade

Este artigo ressalta a importância da eficientização energética em prédios públicos como uma política pública a ser adotada pelos gestores municipais, tanto pelo seu efeito demonstrativo de modernidade e alinhamento aos princípios de sustentabilidade como pela indução do desenvolvimento socioambiental, tecnológico e do mercado. São apresentadas as razões e os desafios para enfrentamento dos problemas relacionados ao alto consumo de energia elétrica em prédios públicos municipais, além de um conjunto de propostas objetivas à adoção de uma nova abordagem para a gestão da demanda e do consumo nessas instalações, destacando-se o estudo e diagnóstico realizado para o governo do município de São Paulo e exemplos ou casos de sucesso, a serem explorados e seguidos.

Estudo da moagem de alta energia e sinterização de pós compósitos W-Cu

The Tungsten/copper composites are commonly used for electrical and thermal objectives like heat sinks and lectrical conductors, propitiating an excellent thermal and electrical conductivity. These properties are dependents of the composition, crystallite size and production process. The high energy milling of the powder of W-Cu produces an dispersion high and homogenization levels with crystallite size of W very small in the ductile Cu phase. This work discusses the effect of the HEM in preparation of the W-25Cu composite powders. Three techniques of powder preparation were utilized: milling the dry with powder of thick Cu, milling the dry with powder of fine Cu and milling the wet with powder of thick Cu. The form, size and composition of the particles of the powders milled were observed by scanning electron microscopy (SEM). The X-ray diffraction (XRD) was used to analyse the phases, lattice parameters, size and microstrain of the crystallite. The analyse of the crystalline structure of the W-25Cu powders milled made by Rietveld Method suggests the partial solid solubility of the constituent elements of the Cu in lattice of the W. This analyse shows too that the HEM produces the reduction high on the crystallite size and the increase in the lattice strain of both phases, this is more intense in the phase W

Estudo e desenvolvimento de um capacitor eletrolítico de nióbio

It seeks to find an alternative to the current tantalum electrolytic capacitors in the market due to its high cost. Niobium is a potential substitute, since both belong to the same group of the periodic table and because of this have many similar physical and chemical properties. Niobium has several technologically important applications, and Brazil has the largest reserves, around 96%. There are including niobium in reserves of tantalite and columbite in Rio Grande do Norte. These electrolytic capacitors have high capacitance specifies, ie they can store high energy in small volumes compared to other types of capacitors. This is the main attraction of this type of capacitor because is growing demand in the production of capacitors with capacitance specifies increasingly high, this because of the miniaturization of various devices such as GPS devices, televisions, computers, phones and many others. The production route of the capacitor was made by powder metallurgy. The initial niobium powder supplied by EEL-USP was first characterized by XRD, SEM, XRF and laser particle size, to then be sieved into three particle size, 200, 400 e 635mesh. The powders were then compacted and sintered at 1350, 1450 and 1550°C using two sintering time 30 and 60min. Sintering is one of the most important parts of the process as it affects properties as porosity and surface cleaning of the samples, which greatly affected the quality of the capacitor. The sintered samples then underwent a process of anodic oxidation, which created a thin film of niobium pentóxido over the whole porous surface of the sample, this film is the dielectric capacitor. The oxidation process variables influence the performance of the film and therefore the capacitor. The samples were characterized by electrical measurements of capacitance, loss factor, ESR, relative density, porosity and surface area. After the characterizations was made an annealing in air ate 260ºC for 60min. After this treatment were made again the electrical measurements. The particle size of powders and sintering affected the porosity and in turn the specific area of the samples. The larger de area of the capacitor, greater is the capacitance. The powder showed the highest capacitance was with the smallest particle size. Higher temperatures and times of sintering caused samples with smaller surface area, but on the other hand the cleaning surface impurities was higher for this cases. So a balance must be made between the gain that is achieved with the cleaning of impurities and the loss with the decreased in specific area. The best results were obtained for the temperature of 1450ºC/60min. The influence of annealing on the loss factor and ESR did not follow a well-defined pattern, because their values increased in some cases and decreased in others. The most interesting results due to heat treatment were with respect to capacitance, which showed an increase for all samples after treatment

Efeito da moagem de alta energia na microestrutura e nas propriedades magnéticas do compósito wc-10%p.Co

This work a studied the high energy milling effect in microstructure and magnetic properties of the WC-10wt.%Co composite. The composite powders were prepared by mechanical mixed and milled at 2 hours, 100 hours, 200 hours and 300 hours in planetary milling. After this process the composite were compacted in stainless steel die with cylindrical county of 10 mm of diameter, at pressure 200 Mpa and sintered in a resistive furnace in argon atmosphere at 1400 oC for 5 min. The sintered composite were cutted, inlaid, sandpapered, and polished. The microestrutural parameters of the composite was analyzed by X-ray diffraction, scanning electronic microscopy, optical microscopy, hardness, magnetic propriety and Rietveld method analyze. The results shows, with milling time increase the particle size decrease, it possibility minor temperature of sintering. The increase of milling time caused allotropic transformation in cobalt phase and cold welding between particles. The cold welding caused the formation of the particle composite. The X-ray diffraction pattern of composite powders shows the WC peaks intensity decrease with the milling time increase. The X-ray diffraction pattern of the composite sintered samples shows the other phases. The magnetic measurements detected a significant increase in the coercitive field and a decrease in the saturation magnetization with milling time increase. The increase coercitive field it was also verified with decrease grain size with milling time increase. For the composite powders the increase coercitive field it was verified with particle size reduction and saturation magnetization variation is relate with the variation of free cobalt. The Rietveld method analyze shows at milling time increase the mean crystalline size of WC, and Co-cfc phases in composite sintered sample are higher than in composite powders. The mean crystallite size of Co-hc phase in composite powders is higher than in composite sintered sample. The mean lattice strains of WC, Co-hc and Co-cfc phases in composite powders are higher than in composite sintered samples. The cells parameters of the composite powder decrease at milling time increase this effect came from the particle size reduction at milling time increase. In sintered composite the cells parameters is constant with milling time increase

Nanopartíulas de magnetita com oxacilina obtida por moagem de alta energia para aplicações biomédicas

The drug targeting has been the subject of extensive studies in order to develop site-specific treatments that minimize side effects and become more effective anticancer therapy. Despite considerable interest in this class, drugs like antibiotics also have limitations, and have been neglected. Using new pharmaceutical technologies, the use of magnetic vectors appear as promising candidate for drug delivery systems in several studies. Small magnetic particles bound to the drug of interest can be modulated according to the orientation of a magnet outside the body, locating and holding in a specific site. In this work, we propose the use of High Energy Milling (HEM) for synthesis of a magnetic vector with characteristics suitable for biomedical applications by intravenous administration, and for the formation of an oxacillin-carrier complex to obtain a system for treating infections caused by Staphylococcus aureus. The results of the variation of milling time showed that the size and structural properties of the formed material change with increasing milling time, and in 60 hours we found the sample closest to the ideal conditions of the material. The vector-drug system was studied in terms of structural stability and antimicrobial activity after the milling process, which revealed the integrity of the oxacillin molecule and its bactericidal action on cultures of Staphylococcus aureus ATCC

Nutrient digestibility, but not mineral absorption, is age-dependent in cats

Availability of nutrients is influenced by extremes of age, and a better characterization of this influence is necessary for appropriate development of foods and nutritional management throughout life stages of cats. This study investigated nutrient digestibility, mineral absorption, faeces and urine production in three groups of six young, mature and old cats fed two diets containing different energy densities. Apparent digestibility and mineral absorption were calculated by total collection method and values were tested with ANOVA and regression analysis. A quadratic relationship was detected between age and digestibility of dry matter, organic matter, crude protein, acid-hydrolysed fat and starch in the low-energy diet. Starch digestibility showed the same response in the high-energy diet. Young adult cats had intermediate digestibility, mature cats the highest and old cats the lowest. Mineral absorption (calcium, phosphorus, magnesium, sodium, potassium and chloride) and urinary pH were not different among groups. These findings confirm previous studies that found low digestibility of nutrients in some old cats, and support evidence that this trend is even more important in less digestible dry foods. on the contrary, data suggest that mineral formulations do not need to be varied in diets for adult cats of different ages.

Viscosidade do Sangue como Parâmetro de Diagnóstico da Síndrome Ascítica em Linhagens de Frangos de Corte com Diferentes Suscetibilidade

O objetivo deste trabalho foi investigar o desenvolvimento de ascites em duas linhagens diferentes de frangos de corte, Hubbard e Pescoço-pelado, através da variação da viscosidade do sangue. As aves foram criadas até 45 dias de idade em duas temperaturas ambiente diferentes (termoneutra e fria) e com dieta de ração à base de milho e farelo de soja, peletizada e de alta energia. Aos 28 e 45 dias de idade, amostras de 8 mL de sangue foram obtidas para determinação da viscosidade aparente em um viscosímetro de cilindros concêntricos da marca Brookfield, modelo LVDII+ e para determinação do hematócrito. Aos 28 dias de idade foram verificadas algumas ocorrências de ascite nas aves da linhagem Hubbard criadas à temperatura ambiente fria, e aos 45 dias de idade, todos os frangos de corte dessa linhagem criados no ambiente frio apresentaram ascite. A linhagem Pescoço-pelado foi resistente ao desenvolvimento de ascite em todas as idades e temperaturas ambiente. A análise dos resultados da viscosidade aparente do sangue indicaram que aves com valores similares ou maiores que 4 cP (centipoise) apresentaram ascite. Podemos concluir que na linhagem comercial o valor de 4 cP para a viscosidade aparente parece identificar o desenvolvimento de ascite.

Influência do Nível de Energia da Dieta sobre a Expressão Hepática de Hsp70-kDa em Frangos Submetidos ao Estresse Calórico Agudo

Este trabalho foi desenvolvido com o objetivo de pesquisar o efeito da energia da dieta sobre a temperatura do cólon e concentração de proteína de choque térmico (Hsp70) de frangos à temperatura ambiente, bem como durante o estresse calórico agudo. Os frangos foram criados até 51 dias de idade e alimentados com dietas contendo nível de energia alto (13.186 kJ EM/kg) ou baixo (12.139 kJ EM/kg). No 21º e 51º dias de idade, a temperatura do cólon foi medida e amostras de fígado foram obtidas para quantificação da Hsp70 através da análise por Western Blotting.. Nessas mesmas idades, a resposta das aves ao estresse calórico agudo (37º C/5 h) foi avaliada (temperatura colón e Hsp70 no fígado). Os resultados mostraram que aos 21 dias de idade, à temperatura ambiente, a temperatura do cólon e a concentração de Hsp70 hepática não foram afetadas pela energia da dieta, mas, aos 51 dias de idade, os frangos alimentados com baixos teores de energia apresentaram menores concentrações de Hsp70 no fígado. As respostas ao estresse calórico agudo mostraram que as aves alimentadas com dietas de alta energia tiveram menor incremento na temperatura do cólon, bem como no conteúdo de Hsp70 hepático. Os resultados desse estudo sugerem que a síntese de Hsp70 no fígado pode ser afetada pela energia da dieta e que frangos alimentados com altos níveis de energia podem ter a termotolerância alterada em condições de estresse agudo pelo calor.

Níveis do subproduto concentrado da produção de lisina em dietas com alto concentrado para tourinhos Santa Gertrudes em terminação

O experimento foi realizado objetivando-se caracterizar o subproduto concentrado da produção de lisina (SPL) e avaliar o desempenho e as características de carcaça de tourinhos Santa Gertrudes confinados recebendo níveis crescentes desse subproduto na dieta. O SPL resulta do processo de produção de lisina e é parcialmente seco. Apresentou aproximadamente 38% de matéria seca e 85% de proteína bruta na matéria seca, sendo que 79% desse nitrogênio encontrava-se na forma não-protéica. Não foram observados metais pesados em níveis tóxicos. Vinte e sete animais, com dez meses de idade e peso inicial de 242 kg, receberam silagem de milho, 80% de concentrado e 0; 4,5 ou 9,0% de SPL na matéria seca da dieta. O período experimental foi de 115 dias, após 56 dias de adaptação. A inclusão do SPL na dieta determinou efeito quadrático sobre o ganho de peso, o consumo diário de matéria seca, o peso final e o peso de carcaça; efeito linear decrescente sobre a eficiência alimentar e o rendimento de carcaça; e aumento da espessura de gordura de cobertura e do peso do fígado. Não foram observadas diferenças entre tratamentos para a área de olho de lombo. As diferenças no desempenho não foram associadas ao menor consumo de alimentos ou ao teor de enxofre das dietas. O nível de 3,7% de SPL na matéria seca da dieta foi considerado o máximo recomendado para tourinhos em terminação recebendo dietas com alto teor de energia, quando o ganho diário de peso esperado seria de 1,23 kg/animal.

Análise do efeito do tempo da moagem de alta energia no tamanho de cristalito e microdeformação da rede cristalina do WC-Co

Hard metals are the composite developed in 1923 by Karl Schröter, with wide application because high hardness, wear resistance and toughness. It is compound by a brittle phase WC and a ductile phase Co. Mechanical properties of hardmetals are strongly dependent on the microstructure of the WC Co, and additionally affected by the microstructure of WC powders before sintering. An important feature is that the toughness and the hardness increase simultaneously with the refining of WC. Therefore, development of nanostructured WC Co hardmetal has been extensively studied. There are many methods to manufacture WC-Co hard metals, including spraying conversion process, co-precipitation, displacement reaction process, mechanochemical synthesis and high energy ball milling. High energy ball milling is a simple and efficient way of manufacturing the fine powder with nanostructure. In this process, the continuous impacts on the powders promote pronounced changes and the brittle phase is refined until nanometric scale, bring into ductile matrix, and this ductile phase is deformed, re-welded and hardened. The goal of this work was investigate the effects of highenergy milling time in the micro structural changes in the WC-Co particulate composite, particularly in the refinement of the crystallite size and lattice strain. The starting powders were WC (average particle size D50 0.87 μm) supplied by Wolfram, Berglau-u. Hutten - GMBH and Co (average particle size D50 0.93 μm) supplied by H.C.Starck. Mixing 90% WC and 10% Co in planetary ball milling at 2, 10, 20, 50, 70, 100 and 150 hours, BPR 15:1, 400 rpm. The starting powders and the milled particulate composite samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to identify phases and morphology. The crystallite size and lattice strain were measured by Rietveld s method. This procedure allowed obtaining more precise information about the influence of each one in the microstructure. The results show that high energy milling is efficient manufacturing process of WC-Co composite, and the milling time have great influence in the microstructure of the final particles, crushing and dispersing the finely WC nanometric order in the Co particles

Obtenção de pós de Nb a partir da redução aluminotérmica com ignição por plasma

The aluminothermic reduction consists in an exothermic reaction between a metallic oxide and aluminum to produce the metal and the scum. The extracted melted metal of that reaction usually comes mixed with particles of Al2O3 resulting of the reduction, needing of subsequent refine to eliminate the residual impure as well as to eliminate porosities. Seeking to obtain a product in powder form with nanometric size or even submicrometric, the conventional heat source of the reaction aluminothermic , where a resistor is used (ignitor) as ignition source was substituted, for the plasma, that acts more efficient way in each particle of the sample. In that work it was used as metallic oxide the niobium pentoxide (Nb2O5) for the exothermal reaction Nb2O5 + Al. Amounts stoichiometric, substoichiometric and superestoichiometric of aluminum were used. The Nb2O5 powder was mixed with aluminum powder and milled in planetarium of high energy for a period of 6 hours. Those powders were immerged in plasm that acts in a punctual way in each particle, transfering heat, so that the reaction can be initiate and spread integrally for the whole volume of the particle. The mixture of Nb2O5 + Al was characterized through the particle size analysis by laser and X-ray diffraction (DRX) and the obtained product of reaction was characterized using the electronic microscopy of sweeping (MEV) and the formed phases were analyzed by DRX. Niobium powders with inferior sizes to 1 mm were obtained by that method. It is noticed, through the analysis of the obtained results, that is possible to accomplish the aluminothermic reduction process by plasma ignition with final particles with inferior sizes to the original oxide

Estudo do equilíbrio líquido-vapor do sistema água+etanol+líquido iônico visando a separação do álcool anidro

Anhydrous ethanol is used in chemical, pharmaceutical and fuel industries. However, current processes for obtaining it involve high cost, high energy demand and use of toxic and pollutant solvents. This problem occurs due to the formation of an azeotropic mixture of ethanol + water, which does not allow the complete separation by conventional methods such as simple distillation. As an alternative to currently used processes, this study proposes the use of ionic liquids as solvents in extractive distillation. These are organic salts which are liquids at low temperatures (under 373,15 K). They exhibit characteristics such as low volatility (almost zero/ low vapor ), thermal stability and low corrosiveness, which make them interesting for applications such as catalysts and as entrainers. In this work, experimental data for the vapor pressure of pure ethanol and water in the pressure range of 20 to 101 kPa were obtained as well as for vapor-liquid equilibrium (VLE) of the system ethanol + water at atmospheric pressure; and equilibrium data of ethanol + water + 2-HDEAA (2- hydroxydiethanolamine acetate) at strategic points in the diagram. The device used for these experiments was the Fischer ebulliometer, together with density measurements to determine phase compositions. The experimental data were consistent with literature data and presented thermodynamic consistency, thus the methodology was properly validated. The results were favorable, with the increase of ethanol concentration in the vapor phase, but the increase was not shown to be pronounced. The predictive model COSMO-SAC (COnductor-like Screening MOdels Segment Activity Coefficient) proposed by Lin & Sandler (2002) was studied for calculations to predict vapor-liquid equilibrium of systems ethanol + water + ionic liquids at atmospheric pressure. This is an alternative for predicting phase equilibrium, especially for substances of recent interest, such as ionic liquids. This is so because no experimental data nor any parameters of functional groups (as in the UNIFAC method) are needed

Structural characterization and Curie temperature determination of a sodium strontium niobate ferroelectric nanostructured powder

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)