Today's electric power system is operated under increasingly stressed conditions. As electrical demand increases, the existing grid is operated closer to its stable operating limits while maintaining high reliability of electric power delivery to its customers. Protective schemes are designed to account for pressures towards unstable operation, but there is always a tradeoff between security and dependability of this protection. Adaptive relaying schemes that can change or modify their operation based on prevailing system conditions are an example of a protective scheme increasing reliability of the power system. The purpose of this thesis is to validate and analyze implementation of the Security-Dependability Adaptive Voting Scheme. It is demonstrated that this scheme can be implemented with a select few Phasor Measurement Units (PMUs) reporting positive sequence currents to a Phasor Data Concentrator (PDC). At the PDC, the state of the power system is defined as Stressed or Safe and a set of relays either vote or perform normal operation, respectively. The Adaptive Voting Scheme was implemented using two configurations: hardware- and software-based PDC solutions. Each was shown to be functional, effective, and practical for implementation. Practicality was based on the latency of Wide Area Measurement (WAM) devices and the added latency of relay voting operation during Stressed conditions. Phasor Measurement Units (PMUs), Phasor Data Concentrators (PDCs), and relay operation delays were quantified to determine the benefits and limitations of WAMS protection and implementation of the voting scheme. It is proposed that the delays injected into the existing protection schemes would have minimal effect on the voting scheme but must be accounted for when implementing power system controls due to the real-time requirements of the data. / Master of Science

This thesis project investigates, analyzes, designs, simulates, constructs and tests a dual-axis solar tracker system to track the sun and concentrates the heat of the sunlight, using a Fresnel lens, into a small area, which is above of an evaporator, to increase the temperature of the seawater to convert it into freshwater. The dual-axis solar tracker was designed with the main objectives that the structure was portable, dismountable, lightweight, low cost, corrosion resistant, wires inside pipes, accurate, small size, follow the sun automatically, off-grid (electrical), use green energy (solar powered), and has an empty area right below of the lens. First, a 500 mm diameter flat Fresnel lens was selected and simulated based on an algorithmic method achieved by a previous PhD student at UNT using MATLAB®, to give the optimization lens dimensions. The lens profile was drawn with AutoCAD®, then output profile lens was simulated in COMSOL Multiphysics®. The objective was to provide the high efficiency, optimum and high precision of the focal rays and heat to the receiver of the evaporator. A novel dual-axis solar tracker system was then designed that is portable, dismountable, lightweight and corrosion resistant. The solar tracker tracks the sun in two axis of rotation automatically during the day time, maximizing the angles of inclination on each axis. After testing computer simulations, the dual-axis solar tracker system was constructed and tested. Last, a detailed cost analysis was performed of the entire project. The outcome of this work can be applied for desalination seawater purposes or other any Fresnel lens application that require a focal high temperature directed by dual-axis solar tracker system.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This study describes the design and construction of a low-cost linear Fresnel solar concentrator. Ray-trace simulation models that analyse optical performance were developed and then used to perform sensitivity analyses of various characteristics of linear Fresnel concentrators. The design of a small-scale concentrator was optimised using the simulation models, after which the concentrator was constructed in the solar laboratory. The concentrator consists of a single-motor tracking system, flat primary mirrors and a low-cost secondary concentrator that approximates a compound parabolic concentrator. Testing revealed satisfactory performance that was comparable to the simulation models’ prediction. The construction of a low-cost solar concentrator that can replace existing thermal sources for the generation of power and process heat is thus achievable. / AFRIKAANSE OPSOMMING: Die ontwerp en konstruksie van 'n laekoste- lineêre Fresnel-sonkonsentreerder word in hierdie studie beskryf. Stralingsimulasiemodelle wat optiese werksverrigting analiseer is ontwikkel en gebruik om sensitiwiteitsanalises van die verskillende eienskappe van lineêre Fresnel-konsentreerders te doen. Die modelle is verder gebruik om die ontwerp van 'n kleinskaalse konsentreerder te optimeer, waarna die konsentreerder in die sonlaboratorium gebou is. Die konsentreerder bestaan uit 'n enkelmotorvolgingstelsel, plat primêre spieëls en 'n laekoste- sekondêre konsentreerder soortgelyk aan 'n saamgestelde, paraboliese konsentreerder. Toetsing dui bevredigende werksverrigting aan, vergelykbaar met wat die simulasiemodelle voorspel het. Dit is dus moontlik om 'n laekoste-sonkonsentreerder wat bestaande termiese bronne vir kragopwekking en proseshittegenerasie kan vervang, daar te stel.

A vinhaça é um dos resíduos da produção de etanol, considerada de elevada capacidade poluidora. Estima-se que para cada litro de etanol produzido, produz-se entre 10 até 15 litros de vinhaça. Porém, este mesmo subproduto pode ser utilizado para geração de eletricidade, fertilizantes, biogás e obtenção de créditos de carbono a partir de biodigestores e concentradores. Logo, a vinhaça pode vir a contribuir para um incremento na geração de energia elétrica e de outros produtos para fomento de renda para o setor sucroenergético e resolver o problema ambiental no que se refere ao descarte in natura. Ante o exposto, justifica-se um estudo sobre a utilização da vinhaça, norteada pela problemática: qual a viabilidade econômica, ambiental e energética da utilização do biodigestor IC, concentrador de vinhaça e o conjugado de ambos? O objetivo geral foi analisar a viabilidade energética, ambiental e econômica da utilização de vinhaça em concentradores, biodigestores IC e em ambos para geração de eletricidade, fertilizantes e créditos de carbono. Para responder à pergunta, a metodologia utilizada na pesquisa foi a análise de viabilidade econômica, aonde foi calculado o VPL, TIR, payback e o payback descontado. Sendo qual foi calculado o consumo anual de Diesel no transporte de vinhaça biodigerida e concentrada, balanço de energia no consumo de Diesel e gerada pelo biogás por ano, balanço de geração e consumo de eletricidade e equivalente populacional de geração de eletricidade de vinhaça e, por fim, a análise ambiental, aonde foi calculado o equivalente populacional de vinhaça biodigerida e concentrada, balanço de emissão e mitigação de NOx, SOx e CO2 eq. pelo concentrador, transporte de vinhaça concentrada, ambas as três análises para uma faixa de produção de etanol de 500 até 4.000 m3/dia, como também para estados brasileiros produtores desse combustível. Como resultado pode-se constatar que os fertilizantes têm importância na viabilidade econômica dos biodigestores IC e concentradores de vinhaça, em cenários sem isenções tributárias e taxa mínima de atratividade 15% a.a. A eletricidade por si só terá viabilidade em cenário com baixa taxa mínima de atratividade de 11% e isenções fiscais. No que se refere a análise energética, destacam-se os resultados do biodigestor IC nas dimensões equivalente populacional e balanço de geração e consumo de eletricidade e na análise ambiental destaca-se o conjugado biodigestor IC e concentrador para as dimensões equivalente populacional e dióxido de carbono equivalentes emitidos e mitigados. Pode-se constatar a partir dos resultados alcançados e da revisão bibliográfica realizada os seguintes cenários desfavoráveis em potêncial para reutilização de vinhaça: baixo preço do MWh tanto no ACR quanto no ACL, incipiência no mercado de eletricidade, elevado investimento em transmissão, ausência de políticas públicas de incentivo a utilização de matéria orgânica proveniente da agropecuárias, ausência de políticas públicas de incentivo a utilização de energias renováveis, experiências não exitosas pelas usinas de utilização de vinhaça para produção de biogás, biodigestores em processo de consolidação tecnológica, incapacidade de financiamento do setor sucroenergético, preço dos concentradores de vinhaça, omissão legislativa referente ao descarte de vinhaça e descapitalização das usinas sucroenergeticas. / Vinasse is one of the residues from the production of ethanol, considered polluting high capacity. It is estimated that for every liter of ethanol produced, produces between 10 to 15 liters of vinasse. However, this same byproduct can be used for generating electricity, fertilisers, biogas and obtaining carbon credits from bio-digesters and concentrators. Soon, vinasse might contribute to an increase in the generation of electricity and other products to promote income for the sugar-energy sector and solve the environmental problem as regards disposal in natura. Against the above, if a study on the use of vinasse, guided by the problem: what is the economic viability, environmental and energy use of the biodigestor, vinasse concentrator and the conjunction of both? The overall objective was to analyze the energy, environmental and economic feasibility of the use of vinasse in hubs, biodigestors IC and in both for electricity generation, fertilizer and carbon credits. To answer, the methodology used in the research was the economic feasibility analysis, where it was calculated the NPV, IRR, payback and discounted payback. Being what was calculated the annual Diesel consumption of biodigerida and concentrated vinasse, energy balance in the consumption of Diesel and biogas generated per year, generation and balance electricity consumption and electricity generation population equivalent of vinasse and, finally, the environmental analysis, where it was calculated the population equivalent of biodigerida and concentrated vinasse emission and mitigation balance of NOx, SOx and CO2 eq. by concentrator, concentrated vinasse transport, both three analysis for a range of ethanol production from 500 to 4,000 m3/day, as well as to the Brazilian States that fuel producers. As a result one can note that fertilizers have importance in the economic viability of bio-digesters IC and vinasse concentrators, in scenarios without tax exemptions and minimum rate of 15% p.a. attractiveness The electricity itself will have viability in scenario with lower minimum rate of 11% attractiveness and tax exemptions. With regard to energy analysis, include the results of the biodigestor IC equivalent dimensions of population and balance of generation and electricity consumption and environmental analysis is the conjugate biodigestor IC and concentrator for the dimensions and equivalent carbon dioxide equivalent emitted and mitigated. You can see from the results achieved and the literature review carried out the following unfavourable scenarios on potential for reuse of vinasse: low price of MWh in both the ACR and the ACL, the effects on the market of electricity, high investment in transmission, absence of public policies to encourage the use of organic matter from the cattle-breeding, absence of public policies to encourage the use of renewable energy , not successful experiences through the use of vinasse plants for production of biogas, biodigesters consolidation technology, inability to finance the sugar ethanol sector, price of vinasse concentrators, legislative omission concerning the discharge of vinasse and decapitalization of sucroenergeticas plants.

<p>One of the traditional approaches to reduce costs of solar energy is to use inexpensive reflectors to focus the light onto highly efficient solar cells. Several research projects have resulted in designs, where the excess heat is used as solar thermal energy.</p><p>Unlike a solar thermal system, which has a selective surface to reduce the radiant heat loss, a CPV/T (Concentrating PhotoVoltaic/Thermal) system uses a receiver covered with solar cells with high thermal emittance.</p><p>This project analyzes whether the heat loss from the receiver can be reduced by covering parts of the receiver surface, not already covered with solar cells, with an optically selective coating. Comparing different methods of applying such a coating and the long-term stability of low cost alternatives are also part of the objectives of this project.</p><p>To calculate the heat loss reductions of the optically selective surface coating a mathematical model was developed, which takes the thermal emittances and the solar absorptances of the different surfaces into account. Furthermore, a full-size experiment was constructed to verify the theoretical predictions.</p><p>The coating results in a heat loss reduction of approximately 20 % in such a CPV/T system and one of the companies involved in the study is already changing their design to make use of the results.</p>

Made available in DSpace on 2014-12-17T14:58:07Z (GMT). No. of bitstreams: 1 RicardoEBRF_DISSERT.pdf: 4014057 bytes, checksum: 4ee7665398e3d4e0b140690a65f6b5c4 (MD5) Previous issue date: 2011-02-28 / Universidade Federal do Rio Grande do Norte / Given the growing environmental crisis caused by degradation, mainly due to the use of polluting energy sources, increasing the growing use of renewable energies worldwide, with emphasis on solar energy, an abundant supply and available to everyone, which can be harnessed in several ways: electricity generation; dehydration of food; heating, disinfection and distillation and cooking. The latter has as its primary feature the viability of clean, renewable energy for society, combating ecological damage caused by large-scale use of firewood for cooking foods, use in tropical countries with high solar radiation, and has funding NGOs throughout the world with the goal of achieving low-income population. The proposed project consists of a solar cooker for concentration, working from the reflection of sunlight by a hub that they converge to a focal point at the bottom of the pot, getting lots of heat. The solar cooker under study consists of two elliptical reflecting parabolas made from the recycling of scrap TV antenna, having 0.29 m? of surface area for each antenna, which were covered by multiple mirrors of 2 mm thick and mounted on a metal structure, with correction for the mobility of the apparent movement of the sun. This structure was built with the recycling of scrap metal, possessing a relatively low cost compared with other solar cookers, around US$ 50.00. This cost becomes negligible, since that will involve a great benefit to not have fuel costs for each meal, unlike the use of gas or firewood for cooking food. The tests show that the cooker has reached the maximum temperature of 740 ? C, for boiling water in an average time of 28 minutes, cooking various types of foods such as potatoes, rice and pasta in an average time of 45 minutes and still going as a solar oven, making pizza baking and meat. These cooking times do not differ much from the cooking times on a gas stove, it becomes the solar cooker as a good consumer acceptance, and furthermore not to deliver the same gases that can poison the food as with the wood stove. Proves the viability of using the stove to cook or bake in two daily meals for a family, still presenting a position to improve his performance with the addition of new materials, equipment and techniques / Diante da crescente crise ambiental provocada pela degrada??o, principalmente devido ao uso de fontes energ?ticas poluentes, cada vez mais, vem crescendo o uso de energias renov?veis em todo o mundo, tendo destaque para a energia solar, uma fonte abundante e dispon?vel a todos, que pode ser aproveitada de diversas maneiras como: gera??o de eletricidade; desidrata??o de alimentos; aquecimento, desinfec??o e destila??o de ?gua e coc??o. Este ?ltimo tem como aspecto primordial a viabiliza??o de energia limpa e renov?vel para a sociedade, combatendo os danos ecol?gicos causados pela utiliza??o em larga escala de lenha para o cozimento de alimentos, tendo utiliza??o em pa?ses tropicais com altos ?ndices de radia??o solar, possuindo financiamento de ONGS por todo o mundo com objetivo de atingir a popula??o de baixa renda. O projeto proposto consta de um fog?o solar ? concentra??o, funcionando a partir da reflex?o dos raios solares por um concentrador que converge os mesmos para um ponto focal no fundo da panela, recebendo grande quantidade de calor. O fog?o solar em estudo ? composto por duas par?bolas refletoras de forma el?ptica feitas a partir do reaproveitamento de sucatas de antena de TV, possuindo 0,29 m? de ?rea superficial para cada antena, que foram cobertas por m?ltiplos espelhos de 2 mm de espessura e montadas em uma estrutura met?lica com mobilidade para a corre??o do movimento aparente do sol. Esta estrutura foi constru?da com o reaproveitamento de sucata, possuindo um custo relativamente baixo, quando comparado com outros fog?es solares, em torno R$ 100,00. Este custo torna-se insignificante, uma vez que promover? um grande benef?cio em n?o possuir gastos com combust?vel para cada refei??o, diferente do uso do g?s ou de lenha para cozinhar alimentos. Os ensaios mostram que o fog?o chegou ? temperatura m?xima de 740?C, realizando a ebuli??o de ?gua em um tempo m?dio de 28 minutos, cozinhando diversos tipos de alimentos, como batata, arroz e macarr?o em um tempo m?dio de 45 minutos e ainda funcionando como forno solar, realizando o assamento de pizza e carnes. Esses tempos de cozimento n?o diferem muito dos tempos de cozimento em um fog?o ? g?s, fato que obt?m ao fog?o solar uma boa receptividade aos consumidores, al?m do mesmo n?o emitir gases que podem intoxicar os alimentos como no caso do fog?o a lenha. Comprova-se a viabilidade da utiliza??o do fog?o para cozinhar ou assar em duas refei??es di?rias para uma fam?lia, apresentando ainda condi??es de melhorar sua performance com adi??o de novos materiais, equipamentos e t?cnicas

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Amid the great crisis of the energy, new methods for electric power generation, especially those do not harm the environment, are constantly sought to meet the growing need worldwide. Among them, the use of Fresnel linear concentrators becomes increasingly feasible, due to have lower cost in comparison to other types of solar concentrators. Thus, the project seeks to develop techniques that optimize use of the system where the main objective is to implement and validate the tracking system for a prototype of linear Fresnel solar concentrator, operating between approximately 7:30 and 16:30 in Fortaleza, CearÃ. For that, it used microcontrollers, sensors and motors to design a system capable of tracking Solar light system. The characterization and validation of the inductive position sensor used is also an important part of the work. To perform the tracking system, have been used a theoretical methodology for relative location of the sun, beyond the gain scheduling technique in control of employee movement. The position sensor validation have a maximum error than 0.3Â. Therefore, can consider that, with the use of the techniques employed for the achievement of system of control, the medium error obtained was about 0.06Â, making the design perform the concentration of solar rays in the absorber concentrator with a maximum deviation of 0.5Â, providing the desired reliability for system use. / Em meio Ãs grandes crises no ambiente energÃtico novos mÃtodos para geraÃÃo de energia elÃtrica, principalmente aqueles que nÃo agridem o meio ambiente, sÃo procurados constantemente para suprir a crescente necessidade mundial. Dentre eles, o uso de concentradores Solares do tipo Fresnel linear torna-se cada vez mais viÃvel, devido possuir custo inferior a outros tipos de concentradores solar. Com isso, procura-se desenvolver tÃcnicas que otimizem o uso do modelo onde o principal objetivo deste trabalho à implementar e validar o sistema de rastreamento de um protÃtipo de concentrador solar Fresnel linear, com funcionamento compreendido aproximadamente entre 7:30 e 16:30 h, na cidade de Fortaleza, CearÃ. Para tanto, utilizou-se microcontroladores, sensores e motores para projetar um sistema capaz de rastrear a luz Solar. A caracterizaÃÃo e validaÃÃo do sensor de posiÃÃo indutivo utilizado tambÃm à parte importante do trabalho. Para a realizaÃÃo do rastreamento empregou-se uma metodologia teÃrica para localizaÃÃo relativa do Sol, alÃm da tÃcnica de escalonamento de ganho no controle do movimento empregado. A validaÃÃo do sensor de posiÃÃo foi realizada encontrando-se um erro mÃximo em torno de 0,3Â. Portanto, pode-se considerar que, com a utilizaÃÃo das tÃcnicas abordadas para a realizaÃÃo do controle do sistema o erro mÃdio obtido foi cerca de 0,06Â, fazendo com que o projeto realizasse a concentraÃÃo dos raios solares no absorvedor do concentrador com um desvio mÃximo de 0.5Â, fornecendo ao sistema a confiabilidade desejada para sua utilizaÃÃo.

A vinhaça é um dos resíduos da produção de etanol, considerada de elevada capacidade poluidora. Estima-se que para cada litro de etanol produzido, produz-se entre 10 até 15 litros de vinhaça. Porém, este mesmo subproduto pode ser utilizado para geração de eletricidade, fertilizantes, biogás e obtenção de créditos de carbono a partir de biodigestores e concentradores. Logo, a vinhaça pode vir a contribuir para um incremento na geração de energia elétrica e de outros produtos para fomento de renda para o setor sucroenergético e resolver o problema ambiental no que se refere ao descarte in natura. Ante o exposto, justifica-se um estudo sobre a utilização da vinhaça, norteada pela problemática: qual a viabilidade econômica, ambiental e energética da utilização do biodigestor IC, concentrador de vinhaça e o conjugado de ambos? O objetivo geral foi analisar a viabilidade energética, ambiental e econômica da utilização de vinhaça em concentradores, biodigestores IC e em ambos para geração de eletricidade, fertilizantes e créditos de carbono. Para responder à pergunta, a metodologia utilizada na pesquisa foi a análise de viabilidade econômica, aonde foi calculado o VPL, TIR, payback e o payback descontado. Sendo qual foi calculado o consumo anual de Diesel no transporte de vinhaça biodigerida e concentrada, balanço de energia no consumo de Diesel e gerada pelo biogás por ano, balanço de geração e consumo de eletricidade e equivalente populacional de geração de eletricidade de vinhaça e, por fim, a análise ambiental, aonde foi calculado o equivalente populacional de vinhaça biodigerida e concentrada, balanço de emissão e mitigação de NOx, SOx e CO2 eq. pelo concentrador, transporte de vinhaça concentrada, ambas as três análises para uma faixa de produção de etanol de 500 até 4.000 m3/dia, como também para estados brasileiros produtores desse combustível. Como resultado pode-se constatar que os fertilizantes têm importância na viabilidade econômica dos biodigestores IC e concentradores de vinhaça, em cenários sem isenções tributárias e taxa mínima de atratividade 15% a.a. A eletricidade por si só terá viabilidade em cenário com baixa taxa mínima de atratividade de 11% e isenções fiscais. No que se refere a análise energética, destacam-se os resultados do biodigestor IC nas dimensões equivalente populacional e balanço de geração e consumo de eletricidade e na análise ambiental destaca-se o conjugado biodigestor IC e concentrador para as dimensões equivalente populacional e dióxido de carbono equivalentes emitidos e mitigados. Pode-se constatar a partir dos resultados alcançados e da revisão bibliográfica realizada os seguintes cenários desfavoráveis em potêncial para reutilização de vinhaça: baixo preço do MWh tanto no ACR quanto no ACL, incipiência no mercado de eletricidade, elevado investimento em transmissão, ausência de políticas públicas de incentivo a utilização de matéria orgânica proveniente da agropecuárias, ausência de políticas públicas de incentivo a utilização de energias renováveis, experiências não exitosas pelas usinas de utilização de vinhaça para produção de biogás, biodigestores em processo de consolidação tecnológica, incapacidade de financiamento do setor sucroenergético, preço dos concentradores de vinhaça, omissão legislativa referente ao descarte de vinhaça e descapitalização das usinas sucroenergeticas. / Vinasse is one of the residues from the production of ethanol, considered polluting high capacity. It is estimated that for every liter of ethanol produced, produces between 10 to 15 liters of vinasse. However, this same byproduct can be used for generating electricity, fertilisers, biogas and obtaining carbon credits from bio-digesters and concentrators. Soon, vinasse might contribute to an increase in the generation of electricity and other products to promote income for the sugar-energy sector and solve the environmental problem as regards disposal in natura. Against the above, if a study on the use of vinasse, guided by the problem: what is the economic viability, environmental and energy use of the biodigestor, vinasse concentrator and the conjunction of both? The overall objective was to analyze the energy, environmental and economic feasibility of the use of vinasse in hubs, biodigestors IC and in both for electricity generation, fertilizer and carbon credits. To answer, the methodology used in the research was the economic feasibility analysis, where it was calculated the NPV, IRR, payback and discounted payback. Being what was calculated the annual Diesel consumption of biodigerida and concentrated vinasse, energy balance in the consumption of Diesel and biogas generated per year, generation and balance electricity consumption and electricity generation population equivalent of vinasse and, finally, the environmental analysis, where it was calculated the population equivalent of biodigerida and concentrated vinasse emission and mitigation balance of NOx, SOx and CO2 eq. by concentrator, concentrated vinasse transport, both three analysis for a range of ethanol production from 500 to 4,000 m3/day, as well as to the Brazilian States that fuel producers. As a result one can note that fertilizers have importance in the economic viability of bio-digesters IC and vinasse concentrators, in scenarios without tax exemptions and minimum rate of 15% p.a. attractiveness The electricity itself will have viability in scenario with lower minimum rate of 11% attractiveness and tax exemptions. With regard to energy analysis, include the results of the biodigestor IC equivalent dimensions of population and balance of generation and electricity consumption and environmental analysis is the conjugate biodigestor IC and concentrator for the dimensions and equivalent carbon dioxide equivalent emitted and mitigated. You can see from the results achieved and the literature review carried out the following unfavourable scenarios on potential for reuse of vinasse: low price of MWh in both the ACR and the ACL, the effects on the market of electricity, high investment in transmission, absence of public policies to encourage the use of organic matter from the cattle-breeding, absence of public policies to encourage the use of renewable energy , not successful experiences through the use of vinasse plants for production of biogas, biodigesters consolidation technology, inability to finance the sugar ethanol sector, price of vinasse concentrators, legislative omission concerning the discharge of vinasse and decapitalization of sucroenergeticas plants.

One of the traditional approaches to reduce costs of solar energy is to use inexpensive reflectors to focus the light onto highly efficient solar cells. Several research projects have resulted in designs, where the excess heat is used as solar thermal energy. Unlike a solar thermal system, which has a selective surface to reduce the radiant heat loss, a CPV/T (Concentrating PhotoVoltaic/Thermal) system uses a receiver covered with solar cells with high thermal emittance. This project analyzes whether the heat loss from the receiver can be reduced by covering parts of the receiver surface, not already covered with solar cells, with an optically selective coating. Comparing different methods of applying such a coating and the long-term stability of low cost alternatives are also part of the objectives of this project. To calculate the heat loss reductions of the optically selective surface coating a mathematical model was developed, which takes the thermal emittances and the solar absorptances of the different surfaces into account. Furthermore, a full-size experiment was constructed to verify the theoretical predictions. The coating results in a heat loss reduction of approximately 20 % in such a CPV/T system and one of the companies involved in the study is already changing their design to make use of the results.

This work deals about the photovoltaic systems, especially with concentration of the sunlight in use of concentrators that are placed direct on the panel. Concentrated photovoltaics systems employ sunlight concentrated onto photovoltaic surfaces for the purpose of more efficient electrical power production. A photovoltaic cell with concentrator includes difractive optical elements that concentrate light on a photovoltaic chip Flat polycarbonate optical element has difractive gratings on its surface.