ABSTRACT The increase in distributed generation (DG) interferes with the energy distribution system, which may present low voltages due to voltage drops and high voltages due to the insertion of distributed generation, resulting from renewable energy sources in rural areas. These voltage levels must be controlled to comply with the limits imposed by the distribution rules and procedures (PRODIST). This study aims to evaluate the voltage rise caused by DG, simulating three DG insertion scenarios, as well as simulate strategies to correct these voltage levels, such as the limitation of the active power supply, the reactive supply by the consumer and the utility, and the installation of on-load tap changers. The simulations were performed using the MATLAB® program, more specifically the PSAT toolbox. Correction techniques were simulated using the active power supply limitation method, the reactive power supply method by consumers, and the voltage regulator process once the voltage rise effect was identified. The first two proved to be ineffective in this case, while the last one meets the voltage levels required by the National Electric Energy Agency.

ABSTRACT The combination of crambe (Crambe abyssinica L.) biodiesel and biogas could be a renewable energy alternative for internal combustion engines. Therefore, the emissions and engine performance of crambe biodiesel blends (B0, B10, B30, B50, B75, and B100) were evaluated in both the dual mode (biogas) and normal mode (biodiesel). The tests were performed on a 5-kVA generator engine at loads ranging from 1 to 4 kW. The power generated in the normal mode was 17% lower than that generated in the dual mode. The dual mode showed a lower specific fuel consumption than the normal mode. In the normal mode, loss of power occurred as the proportion of biodiesel increased. Furthermore, nitrogen oxide emissions decreased with the addition of biogas. In the dual mode, the emissions increased as the biodiesel content increased. Carbon monoxide emissions decreased in both the normal and dual modes with an increase in biodiesel. The addition of biogas in the dual fuel mode with crambe biodiesel is an efficient alternative for partial substitution of diesel.

ABSTRACT Different mechanical configurations of diesel engines, when powered by biogas, can influence engine performance and efficiency. Consequently, this study aims to evaluate various generator engines to determine the optimal configuration for a distributed generation unit at a swine farm. In this study, we assess the biogas consumption, specific consumption, and efficiency of five biogas generator engines. Three engines (A, D, and E) were provided by Biogás Motores Estacionários, while the remaining two (B and C) were provided by Electro Hager models and MWM, respectively. The biogas used was produced in plug flow biodigesters (piston flow) by the treatment of swine waste. Engine A, provided by Biogás Motores Estacionários, exhibited specific consumption at a power of 30 kW (low load) similar to engines B and C. However, engines B and C displayed higher efficiencies at high loads compared to engines A, D, and E, attributed to their advanced fuel injection and control systems.

ABSTRACT In Brazil there is a wide availability of residues, which have been used in the production of biogas and biofertilizers. The engine-generator by biogas is grid connected, and produce electricity for self-consumption and the surplus is inserted into the grid. The aim of the present study was to evaluate energetic efficiency and exhaust gas emission of two cases: two engine-generators sets of 100 kVA running on biogas, produced from residues of a poultry slaughterhouse unit (PSU) and swine fattening unit (SFU). Load variation in the engine-generator set was evaluated in the SMCP (system of protection and synchronism). There was an increase in the emission of nitrogen oxide, sulfur dioxide and exhaust gas temperature, in both cases. The elevation in the load of the engine-generator increased its global efficiency (mechanical plus electric), with levels between 6.12% with load of 10 kW and 20.91% with 70 kW. The average specific consumption of biogas in the load of 70 kW was 0.76 m3 kWh-1 in the swine fattening unit and 0.80 m3 kWh-1 in the slaughterhouse unit with load of 70 kW. The last results show an engine-generator on biogas of 100 kVA (load of 70 kW), spent an average of 1.4 m3 of biogas to produce 1.0 kWh of electricity.

Uma das maiores fontes de energia disponíveis nas áreas rurais e agroindustriais é a biomassa, que aparece na forma de resíduos vegetais e animais, tais como resto de colheita, esterco animal, plantações energéticas e efluentes agroindustriais. Esses resíduos podem ser utilizados pelo produtor rural ou na agroindústria para a queima direta, visando à produção de calor ou à produção de biogás em biodigestores. A produção de suínos gera grande quantidade de dejetos causando problemas ao meio ambiente, que quando não tratados possuem quantidade relevante de metano. Objetivou-se com este trabalho avaliar, economicamente, a produção de energia elétrica via biogás da suinocultura. Constatou-se que a melhor opção para o produtor é a venda de crédito carbono quando o custo de produção de energia elétrica é viável quando vendido à concessionária de energia. A melhor condição encontrada foi a de geração de 20 h d-1, caso o tempo de retorno do investimento seja de 8 anos e o valor de produção de energia elétrica, de R$ 120,11 kWh.

One of the biggest sources of energy available in rural areas is biomass and agribusiness. The same appears in the form of plant and animal residues such as crop residues, animal manure, energy crops and agro-industrial effluents. These residues can be used by the farmer or agribusiness for direct burning in order to produce heat or production of biogas. Swine production generates large amounts of wastes causing environmental problems if left untreated. The same has lot of methane. The objective of this study was to evaluate the production cost of electricity through biogas from swine manure. It was found that the best option for the producer is selling carbon credit when the production cost of electricity is viable when sold to utility power. The best condition was found to generate 20 h d-1, when the time for return on investment is 8 years and the production of electricity is R$ 120.11 kWh.

O estudo de fontes alternativas de energia ao óleo diesel mineral, como o biodiesel, com origem renovável, é importante para o meio-ambiente e diversificação da matriz energética. Neste estudo foram levantados o consumo específico de combustível, o valor calórico do combustível e a eficiência do conjunto motor gerador da marca BRANCO em função de cargas resistivas, sob as seguintes proporções volumétricas entre o óleo diesel mineral com biodiesel: 0% (B0), 20% (B20), 40% (B40), 60% (B60) e 100% de biodiesel (B100). Para o ensaio utilizou-se motor de 7,36 kW, com gerador elétrico acoplado de 5,5 kW. As cargas utilizadas, 0,5 kW; 1,0 kW; 1,5 kW e 2,0 kW foram elevadas até 5,0 kW, oriundas de um dinamômetro de cargas resistentes. Assim, o desempenho do conjunto para cargas abaixo de 1,5 kW mostrou-se menor, pelo maior consumo específico de combustível (CEC), e redução na eficiência do conjunto motor gerador para a faixa de potência. Para as proporções de biodiesel B40, B60 e B100 os resultados descreveram redução no valor calórico e aumento do CEC. Portanto, realizando comparação das proporções de biodiesel com o óleo diesel, a proporção B20 substitui parcialmente o óleo diesel, sem perdas significativas do desempenho do motor gerador.

The study of mineral diesel alternatives, such as biodiesel, a renewable fuel, is important for the environment and to diversify energy sources. This study evaluated an engine-generator BRANCO brand. Specific fuel consumption, calorific value and the overall efficiency as a function of the system load was measured, using diesel oil and biodiesel blends. The biodiesel proportions in the composition were 0% (B0), 20% (B20), 40% (B40), 60% (B60), and 100% (B100). The engine that was used during the test has a power of 7.36 kW, and the electric generator was 5.5 kW. The group was submitted to resistive loading, in the range: 0.5 kW, 1.0 kW, 1.5 kW; growing up to 5.0 kW. The results have shown that, when operating at lower loads (less than 1.5 kW), the engine-generator performance decreased, while the specific consumption increased, leading to an efficiency reduction. The biodiesel proportions B40, B60 and B100 described reduction in caloric value and increased the specific fuel consumption. Therefore, comparing the proportions of biodiesel with diesel oil, the proportion B20 replaced diesel oil without significant losses in engine-generator performance.

Dentre as alternativas à crescente demanda energética mundial, o uso da biomassa como fonte de energia é uma das formas mais promissoras, pois contribui para a redução das emissões de dióxido de carbono na atmosfera. A gaseificação é uma tecnologia de transformação energética da biomassa num biocombustível gasoso. O gás de gaseificação é um combustível de baixo poder calorífico que pode ser utilizado em motor ciclo Diesel no modo dual para geração de energia elétrica em comunidades isoladas. Este trabalho teve por objetivo avaliar a redução no consumo de Diesel num motor gerador, com a utilização de gás da gaseificação da madeira. O motor avaliado foi da marca BRANCO, com injeção direta e potência de 7,36 kW (10 cv) acoplado a um gerador elétrico de 5,5 kW. O gás de gaseificação foi produzido num gaseificadortipo concorrente, sendo injetado no motor misturado com o ar de admissão e o Diesel injetado pelo injetor do motor (modo dual). O motor gerador foi submetido a cargas que variaram entre 0,5 kW e 3,5 kW, com o auxílio de um banco de resistências elétricas. O consumo de Diesel foi medido por meio de uma balança de precisão. Concluiu-se que o motor convertido para o modo dual, ao utilizar o gás de gaseificação de madeira, apresentou uma redução no consumo de Diesel de até 57%.

Among the alternatives to meet the increasing of world demand for energy, the use of biomass as energy source is one of the most promising as it contributes to reducing emissions of carbon dioxide in the atmosphere. Gasification is a technological process of biomass energy production of a gaseous biofuel. The fuel gas has a low calorific value that can be used in Diesel engine in dual mode for power generation in isolated communities. This study aimed to evaluate the reduction in the consumption of oil Diesel an engine generator, using gas from gasification of wood. The engine generator brand used was a BRANCO, with direct injection power of 7.36 kW (10 HP) coupled to an electric generator 5.5 kW. Diesel oil mixed with intake air was injected, as the oil was injected via an injector of the engine (dual mode). The fuel gas was produced in a downdraft gasifier. The engine generator was put on load system from 0.5 kW to 3.5 kW through a set of electrical resistances. Diesel oil consumption was measured with a precision scale. It was concluded that the engine converted to dual mode when using the gas for the gasification of wood decreased Diesel consumption by up to 57%.

No manejo de animais em propriedades rurais, é necessário o desenvolvimento de equipamentos de climatização de ambientes, tais como os resfriadores evaporativos. No presente estudo, foi construído e testado um resfriador evaporativo alternativo. O sistema é composto por um circuito de circulação de água impulsionada por uma bomba hidráulica e uma rede de tubulação em PVC formadora de uma cortina de água, uma calha condutora de água e um reservatório. A temperatura e a umidade relativa foram medidas na entrada e saída do equipamento, utilizando-se de termo-higrômetro digital, no período de 28 de novembro a 14 de dezembro de 2006 (dias quentes e secos do início de verão) e entre 6 e 13 de março de 2007 (dias quentes e úmidos). Associado a um sistema de ventilação forçada, o dispositivo apresentou, em três testes, resultados que indicaram que a temperatura do ambiente pode ser reduzida na faixa de 3 a 4 ºC e com acréscimo de 10 a 12% de umidade relativa. A máxima eficiência evaporativa obtida foi de 47,6%.

In the management of animals in rural areas, it is necessary the development of environment climatization devices, such as the evaporative coolings. In this study it was set up and tested an alternative evaporative cooling. The system consists in one circuit of water circulation pumped from a hydraulic pump and a net of PVC pipe which makes a water drapery, a water conductor gutter and a reservoir. The temperature and relative humidity were measured in the inlet and outlet of the device, with a digital hygrothermometer between November 28th and December 14th, 2006 (warm and dry days at the beginning of the summer) and between March 6th and 13th, 2007 (warm and humid days). Associated to a ventilation system, the device presented, in three complete phases of tests, results that indicated that the temperature of the environment can be limited to 3 to 4ºC and with addition of 10 to 12% of relative humidity. The greatest evaporative efficiency found was 47.6%.

A conscientização da importância do meio ambiente tem incentivado o estudo de novas fontes energéticas renováveis e menos poluentes. Dentre essas fontes, a energia solar destaca-se por ser perene e limpa. A utilização da energia solar em sistemas de aquecimento de água residencial rural pode colaborar com a economia de energia elétrica, base da matriz energética brasileira. Conhecer os fatores que influenciam na operação de um sistema de aquecimento de água por energia solar é importante na determinação de sua viabilidade técnica, visando a sua difusão em residências rurais. Para tanto, construiu-se um protótipo, no câmpus da Faculdade Assis Gurgacz, em Cascavel - PR, com características similares a um equipamento utilizado em residências para dois habitantes, para funcionar com circulação natural ou termossifão e sem auxílio de sistema de aquecimento complementar. O equipamento mostrou-se viável tecnicamente, alcançando a temperatura mínima para banho de 35 °C, sempre que a radiação solar foi superior a 3.500 Wh m-2, o que aconteceu para a maioria dos dias estudados.

The awareness of the importance of the environment has stimulated the study of new renewed energy sources and less pollutant. Amongst these sources, solar energy stands alone for being perennial and clean. The use of solar energy in systems of agricultural residential water heating, can complement the economy of electric energy, base of the Brazilian energy matrix. Knowing the factors that influence the operation of a system of water heating by solar energy is important in determining their technical viabilities targeting their distribution in agricultural residences. To evaluate equipment of water heating for solar energy, a prototype was constructed in the campus of Assis Gurgacz College, in Cascavel,State of Paraná, Brazil, with similar characteristics to equipment used in residences for two inhabitants, to function with natural circulation or thermosiphon and without help of a complementary heating system. The equipment revealed technical viability, reaching the minimum temperature for shower, of 35 °C, whenever the solar radiation was above the 3,500 Wh m-2, for the majority of the studied days.

Diante da previsão de escassez do petróleo, o éster etílico (biodiesel) tem-se apresentado como excelente opção de combustível alternativo para motores ciclo Diesel. As características do biodiesel são semelhantes às do diesel em termos de viscosidade e poder calorífico, podendo ser utilizado sem adaptações nos motores. Para a realização deste trabalho, utilizou-se de motor ciclo Diesel, de injeção direta, com quatro cilindros, sem adaptações. O motor foi acoplado a um dinamômetro e sistemas de aquisição de dados auxiliares. Avaliaram-se os desempenhos de torque, de potência e de consumo específico de combustível para as seguintes misturas diesel/éster etílico de soja: B2, B5, B10, B20, B50, B75 e B100. O melhor desempenho registrado deu-se com a mistura B20.

Given the prediction of the scarcity of oil, the ethyl ester (biodiesel) has presented as an excellent alternative fuel option for cycle diesel engine. The characteristics of biodiesel are similar of diesel in terms of viscosity and the calorific power, being able to be used without adaptations in the engines. For the accomplishment of this work it was used a cycle diesel engine, of direct injection with four cylinders, without adaptations. The engine was connected to a dynamometer and acquisition systems of auxiliary data. The performances of torque, power and specific fuel consumption for the following mixtures diesel/soy ethyl ester had been evaluated: B2, B5, B10, B20, B50, B75 and B100. The best registered performance was given with the B20 mixture.

O bombeamento de água é uma das atividades mais difundidas quanto ao emprego da energia solar fotovoltaica. Porém, apesar de se apresentar como alternativa interessante, o alto custo, a baixa eficiência dos sistemas e os projetos inadequados restringem sua aplicação. O uso racional, baseado na utilização mais eficiente de seus equipamentos, está vinculado ao conhecimento do comportamento operacional desses sistemas. No presente trabalho, teve-se o objetivo de avaliar o comportamento de um sistema fotovoltaico de bombeamento de água diretamente acoplado, sob diferentes condições de irradiância solar, por meio da montagem de uma bancada de testes, submetendo-o a diferentes alturas manométricas e determinando-se a vazão fornecida. A análise dos resultados permitiu estabelecer um modelo de regressão para estimativa de vazão do sistema em função da irradiância e altura manométrica. Concluiu-se que a potência gerada pelo painel e a vazão fornecida pela motobomba estão diretamente relacionadas à irradiância solar e à altura manométrica e influenciam na eficiência do sistema. A máxima eficiência do painel foi de 8%, 39% para a motobomba e 2,3% na interação dos componentes.

The pumping of water is one of the activities most diffused to the employment of the photovoltaic solar energy, in spite of coming as an interesting alternative, the high cost and it lowers efficiency of the systems with the inadequate projects, still restricts its application. The rational use, based on the most efficient use of its equipments is linked to the knowledge of the operational behavior of these systems. The present work objectified to evaluate the operational behavior of a photovoltaic water pumping directly coupled operating in different conditions of solar irradiance, by means of the assembly of supported tests, submitting to different manometer elevation and determining the supplied rate flux of water. The analysis of the results allowed to determine a regression model for flux of water estimation as function of irradiance and manometer elevation. Was concluded that the power generated by the array and the rate flux supplied by the motor-pump is directly related to the solar irradiance. The maximum efficiency of the array was of 8%, 39% for the motor-pump and, 2.3% in the interaction of the components in the system.