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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

The objective of this research was to study the impacts of large USSE facilities on wildlife movement corridors and habitat connectivity in Florida to identify important habitat patches and movement corridors significant for potential Florida panther (Puma concolor coryi) dispersal, conservation, and recovery. Large carnivores (such as Florida panther) have often been examined as conservation umbrellas for large-scale connectivity planning due to their extensive spatial requirements (Beier et al., 2006, Thorne et al., 2006). In addition, Florida panther is relatively well-studied species that have been listed as endangered under the US Endangered Species Act for over 40 years, due to habitat fragmentation and reduction. Habitat suitability was compared before and after the installation of the USSE facilities using RandomForest model developed by Frakes and Knight (in prep). The connectivity study focused on comparing current density and effective resistance (resistance distance) before and after the installations of USSE facilities and was conducted using Circuitscape 4.0. The impacts on habitat connectivity were the most substantial in the areas where the USSE facilities were installed on or around wildlife corridors, near focal areas, and in large clusters. The study has identified important linkages and new pathways that animals may try to take in order to bypass the facilities. The study has also shown that installation of USSE facilities in areas not suitable as habitat for Florida panthers, but still permeable or semi-permeable (e.g., agricultural lands), can substantially impact connectivity between focal areas. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

The world has an imperative need to switch to clean and renewable energy sources. Effectively harnessing the vast energy that radiates on the earth's surface from the sun is a long standing goal of clean energy proponents. This work introduces the novel concept of a solar energy belt stretched across America. The thesis provides the first steps towards showing that not only can such a belt be built, but it can effectively yield a substantial quantity of America's energy in a cost effective fashion. In order to maximize impact of the work, a general mathematical model is first derived that may be extended by any interested party. The model is then viewed from the perspective of mathematical combinatorics and is thus made subject to combinatorial optimization. Genetic Algorithms are used for this optimization scheme. A GUI and simulation is provided that demonstrates the evolution of the solar belt solution in real-time. Results are demonstrated.

Call number: LD2668 .T4 1984 R515 / Master of Science

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2005. / There are numerous challenges that have to be overcome in order to generate the electrical and thermal energy required to power Antarctic research stations in a technically, economically and environmentally suitable manner. Consequently the costs associated with generating energy at these latitudes are high, and ways are constantly being sought to improve energy generation methods and protect the pristine environment. These endeavours are strongly encouraged by the Antarctic Treaty. This thesis aims to investigate the technical and economic feasibility of using solar energy at South Africa’s SANAE IV (South African National Antarctic Expedition IV) station in Antarctica. The idea of using solar energy in Antarctica is not novel, and as is shown a number of stations have already capitalised on opportunities to generate savings in this manner. Similarly, at SANAE IV, there exists the opportunity to alleviate an increased summer energy load on the station and reduce diesel consumption through the proper implementation of such a system. There is also ample scope to use wind energy, which would have a marked positive impact on the base’s operation. The data used in this thesis was obtained mainly during the 2004/2005 takeover expedition to South Africa’s SANAE IV station in Antarctica. Included are measurements of total and diffuse radiation that were measured during the months of January and February 2005, and which form an important part of the investigation. Since there are currently no radiation sensors, or any historical record of measured radiation at the station, the only measured data available from SANAE IV was the data recorded during the 2004/2005 takeover expedition. By further collecting archived values of fuel consumption, electricity generation and load profiles, an energy audit of the station was also completed during the 2004/2005 takeover expedition. The expected savings that could be generated by solar systems were calculated by considering the use of both photovoltaic and solar thermal devices at the South African station. The 40 kW photovoltaic system that was investigated was able to significantly reduce the load on the dieselelectric generators, however it was only possible to fully recover the initial costs sunk into commissioning the system after 21 years. The installation of such a system would equate to a Net Present Value of 302 915 Rand at the end of the 25 year system lifetime (assuming a real hurdle rate of 8 % and fuel price escalation rate of 5 %), saving 9 958 litres of diesel annually generating energy at a cost of 3.20 Rand/kWh. It should be noted, however, that under more ideal conditions (i.e. less attractive alternative investment opportunities, higher fuel price escalation rates and a stronger emphasis on environmental concerns) investment into a photovoltaic system could potentially breakeven after approximately 10-15 years, while simultaneously significantly improving base operation. Furthermore, it was found that a flat-plate solar thermal collector utilised with the snow smelter at SANAE IV is better suited to generating savings than photovoltaic devices. The average cost of generating electricity after commissioning such a system with a 143 m2 collector field would be approximately 3.13 Rand/kWh, as opposed to the 3.21 Rand/kWh of the current diesel-only system, and would realise an annual fuel saving of approximately 12 245 litres. The system would arrive at a breakeven point after approximately 6 years, and represent a Net Present Value of 2 148 811 Rand after 25 years. By further considering environmental factors such as the cost of removing soiled snow from Antarctica and diesel fuel emissions the magnitude of the net present savings would increase by approximately 500 000 Rand over the expected 25 year project lifetime. The opportunity to install a solar energy system at SANAE IV therefore warrants action. There is potential not only to generate savings over the operational lifetime but also to preserve the environment in accordance with the desires of the Antarctic Treaty. It is firmly believed that with careful planning and implementation such a project can and should be successfully undertaken. / Centre for Renewable and Sustainable Energy Studies

Delafossite CuFeO2 is an intrinsic p-type semiconductor with a band gap around 1.5 eV. Further, it is composed of relatively abundant, nontoxic elements, and therefor have potential to be an attractive material for solar energy harvesting.This work examines three routes to synthesise this material. The first includes a sol-gel deposition and then relies on solid state reaction above 650 degrees Celsius in inert gas atmosphere. In this work, no delafossite is obtained with this method.The second method is a hydrothermal route to make particles under hydrostatic pressure in an autoclave. Delafossite is obtained mixed with other phases.The third route includes aqueous precipitation similar to the second route, but a temperature of 70 degrees Celsius and ambient pressure is sufficient to produce a pure delafossite particle phase. It provides a robust and simple way to make delafossite CuFeO2 particles.The resulting particles are deposited and compressed on glass into thin films.The films have a band gap slightly below 1.5 eV and show some photoactivity in electrochemical measurements.

The Regional Council of Jämtland has a goal to increase the export of renewable energy and with that reduce the total greenhouse gas (GHG) emissions. One of the measures used to reach this goal is to give subsidies and tax reductions for investments in photovoltaics. Photovoltaics are generally perceived as “good for the environment” and give a “good image” to companies. They are marketed as interesting for private persons and farmers from a profitability point of view. Sweden has an electricity mix with average CO2 emissions of 20-30 g/kWh. Compared to other countries in Europe this is very low. The CO2 emissions of photovoltaics during their lifetime are 46 g/kWh according to the International Panel on Climate Change (IPCC). Taking this in consideration it can be concluded that photovoltaics actually increase GHG emissions as they have higher emissions of CO2 than the average in Sweden. When the decision to invest in photovoltaics is made with profitability as a main reason, it is debatable if the subsidies and tax reductions are needed. When the decision to invest in photovoltaics is made with environmental concern as a main reason, the subsidies might be given to other environmental technologies that are better from a climate perspective. Considering this, the push for profitability of photovoltaics can be seen as just another increase in consumption.

Nepal, a country located between India and China, is one of the world’s least developed countries.  Access to electricity is a problem throughout Nepal. Both for the grid connected areas that suffer from power cuts up to 16 hours a day during the dry season, and for remote areas where lack of money, infrastructure or even the location itself set limits for the electrification. In the eastern part of Nepal, around 100 km south of Mount Everest is Thade, a small mountain village with about 200 residents. Until 2015 the village only had an old, dilapidated school building that was in such bad condition that it could barely be used. Therefore, many of the children in the village did not go to school, and it was only the families with enough money that could send their children to a better school. Other children had to walk for hours to reach the nearest school. With contribution and support from a Swedish-Nepali non-government organisation (NGO) a new school opened in May 2015. One year later there are 42 children at the Grace Academy School. One of the main problems for the school today is that they do not have any electricity, which places limitations on both teachers and students. The purpose of this study was to investigate if it is possible, in a simple and sustainable way use a solar cell system with battery storage to meet the basic needs for electricity of the school. The aim was to build a simulation model, of the energy system, in MATLAB’s Simulink® program and then validate the result from that model to the result from the commercial solar system program PVsyst. Tilt and orientation of the panels was optimized specifically for Thade School to get as much electricity as possible from the prevailing conditions. Further, the aim was to, through interviews and conversations with the residents in the village and people connected to the school project, gain an understanding of how electrification of Thade School would affect the school, the teachers and the students, as well as the village and its residents. In general, Nepal has very good conditions for solar power, with around 300 days of sunshine annually. According to the residents of Thade, the weather is usually clear and sunny early in the morning, but after 10am it most often becomes cloudy and foggy. Hence investigation whether solar power in Thade would work is interesting. Electrification of the school would allow for easier learning and most likely increase the status of the school in the surrounding area. It would be easier for students and stuff to get information from the outside world, especially if their plan for Internet access is incorporated in the future. The interest for teachers to come to Thade would perhaps increase. Today the school has a hard time getting good teachers to come, to teach and live in the small mountain village. The children attending the school would also have a better chance to compete with other children to enter University or further educations. The advantages of electrification for Thade are clear.   Three different cases were simulated, with different assumptions of the solar radiation. The results showed that solar power could cover about 95 % of the annual demand, based on the needs that were reported as needed today. / Nepal, ett land inklämt mellan Indien och Kina, är ett av världens minst utvecklade länder. Tillgången på elektricitet är ett problem i hela Nepal, både för de nätanslutna områdena som kan ha strömavbrott upp till 16 timmar per dygn under torrperioden, men även för avlägsna områden där bristen på pengar, infrastruktur eller bara platsen sätter gränser för elektrifiering. I den östra delen av Nepal, ca 100 km söder om Mount Everest, ligger Thade, en liten bergsby med ca 200 invånare. Fram till 2015 hade byn endast en gammal sliten skolbyggnad som var i sådant dåligt skick att den knappt gick att använda. Därför gick många av barnen inte i skolan, och det var bara familjer med mycket pengar som kunde skicka sina barn till bättre skolor. Andra barn var tvungna att gå i timmar för att komma till den närmsta skolan. Med bidrag och stöd från en Svensk-Nepalesisk icke-statlig organisation (NGO), kunde en ny skola öppna i maj 2015. Ett år senare går 42 barn i Grace Academy School. Ett av de största problemen för skolan idag är att de inte har någon elektricitet, vilket skapar begränsningar för både lärare och elever. Syftet är att undersöka om det är möjligt att på ett enkelt och hållbart sätt kunna tillgodose skolans grundläggande behov av el genom ett solcellssystem med batterilagring. Målet är att bygga en simuleringsmodell, över energisystemet, i MATLABs Simulink® program och sedan validera resultatet från den modellen med resultatet från det kommersiella solsystem programmet PVsyst. Lutning och orientering av solpanelerna kommer att optimeras specifikt för Thade skolan för att få ut så mycket energi som möjligt från de rådande förhållandena. Vidare är syftet att genom intervjuer och samtal med invånarna i byn och personer med anknytning till skolprojektet, få en förståelse för hur en elektrifiering av skolan i Thade kan komma att påverka skolan, lärarna och eleverna, men också byn och dess invånare. Nepal har i allmänhet mycket goda förutsättningar för att använda solenergi, med ca 300 soldagar per år. Enligt personerna som bor i Thade är vädret ofta råder ofta klart och soligt på förmiddagen, men ungefär efter klockan 10 blir det ofta molnigt och dimmigt. Av den anledningen är det intressant att undersöka möjligheterna för solenergi i just Thade. Elektrifiering av skolan skulle underlätta utbildningen och förmodligen höja statusen för skolan. Det skulle göra det enklare för både elever och personal att få tillgång till information, speciellt om planen att i framtiden skaffa internet går i lås. Intresset att vara lärare i Thade skulle förhoppningsvis öka. Idag har skolan svårt att få bra lärare som vill komma och undervisa och bo i den lilla bergsbyn. Barnen skulle också få en större chans att tävla med andra barn om att komma in på universitet eller vidareutbildningar. Fördelarna med elektrifiering av Thade skolan är många. Tre olika simuleringar gjordes, med olika antaganden för solinstrålningen. Resultatet visade att solenergin kan täcka ca 95% av den årliga efterfrågan, utifrån de behov som sades behövas idag.

The energy sector is currently in a state of change as conventional energy sources are questioned by the need of new clean and sustainable energy sources to satisfy the global energy demand in the long term. Renewable energies respond to this increasing demand and solar energy is an advanced example of them. Photovoltaic modules are experiencing a steady reduction in their production costs. It is needed that this trend continues and, along with it, their propagation and expansion in the market continues. One way of reducing production costs is by using inexpensive light concentrators to increase the output of the costly photovoltaic cell. In this respect, the Solarus AB hybrid PV/T collector has been designed based on this principle. This collector is a CPC (Compound Parabolic Collector) and belongs to the MaReCo (Maximum Reflector Collector) family. The aim of this thesis is to deeply investigate this technology in two main areas. Firstly, the collector will be tested both electrically and thermally in order to evaluate its performance. To do so, a solar test rig has been built and connected at the building Hall 45 of Högskolan i Gävle, Gävle, Sweden. The second main area of investigation of this thesis is to determine the optimal price for the Solarus AB hybrid PV/T collector in order to be competitive in the solar energy market. This study will be based in the current market prices of photovoltaic and thermal collectors. Regarding the electrical performance of the collector, the results obtained show that the front side of the receiver produces more electricity throughout the day than the reflector side. This has guided Solarus AB to decide to change the design of its receiver to improve its performance. With the current design, it has been obtained a peak power at STC of 220W. In relation with the thermal part, the heat losses of the collector have been estimated obtaining a U value of 6,8W/(m2*K), a thermal optical beam efficiency of 63,5% and a total optical beam efficiency of 74,5%. The price market study of photovoltaic and thermal collector has shown that 2m2 of the Solarus AB hybrid PV/T collector produces approximately the same annual electricity and heat as 1,1m2 of a photovoltaic module with an efficiency of 15,5% and a flat plate collector of 0,85m2 of aperture area. According to the market study, its cost is equivalent to 190€ for the PV module and 220€ for the flat plate collector. This means that the price of the Solarus AB hybrid PV/T collector should be lower than 410€.