Delly Oliveira Filho

Methodology for evaluation of grid-tie connection of distributed energy resources - Case study with photovoltaic and energy storage

The availability of reliable energy sources for all people, especially electricity, indicates an imbalance in the living conditions of a society. Therefore, new systems must be implemented to couple energy storage and renewable energy generation for the grid reliability improvement and increase access to electricity. This paper proposes a methodology to establish a general index focused on the insertion of distributed photovoltaic generation and energy storage using batteries. This methodology was applied in the IEEE 14-bus electric power system with load variation from different energy providers for the period of one year. The simulation results allow of the best performance evaluation to add distributed photovoltaic generation and/or energy storage in a real electric power system in different buses. The proposed methodology will allow planners to at the same time visualize different aspects by means of a single index that includes technical, economic and environmental aspects.

Viabilidade econômica de produção de lenha de eucalipto para secagem de produtos agrícolas

The main objective of this work was to determine the costs and economical feasibility of eucalyptus firewood production for drying of agricultural products. The main technical and economic considerations were: a) use of dried eucalyptus firewood in indirect furnaces; b) costs of manual work, materials, equipments and other inputs; c) interest or opportunity costs 10% per year; d) average land price varying from 500.00 until 2,000.00 US

Reflectometria no domínio do tempo na determinação do conteúdo de água no solo

/hectare; e) forestry management costs 10% per year; f) investment period equal to the eucalyptus production cycle, that is 21 years. It was concluded that the reforestation is feasible economically, when it is implemented on part of the land destined for the agricultural production, furthermore, the land to be used for the forestation for wood production is relatively small, that is 0.50 to 4.23% of the agricultural land for the cultures considered in this study: coffee (natural), corn, beans and soybeans.

Análise energética de sistemas solares térmicos para diferentes demandas de água em uma residência unifamiliar

This study had as objective the determination of the correlation between the apparent dielectric constant and water content for a clay-textured soil and a sandy-textured soil by fitting a cubic polynomial type model. To measure the soil water content a TDR system was proposed, which consists of: oscilloscope; electromagnetic pulse generator; coaxial cable of 50 W; TV antenna cable; impedance matching; probes (paralleled metallic guides) with 0.10, 0.15, 0.20, 0.25, 0.30 and 0.35 m lengths and with two diameters (d1 = 3.2 and d2 = 6.5 mm). For the sandy soil, the best fit was obtained with a 0.30 m-long probe with 3.2 mm-diameter guides, an adjusted determination coefficient, R2, of 0.954. For the clay soil, the best fit was obtained with a 0.30 m-long probe with a 3.2 mm-diameter guides, and an adjusted determination coefficient, R2, of 0.923. The TDR system, proposed for determination of the soil water content within the range between the field capacity and the wilting point, provided the best determination coefficients for the 0.30 m probe in both soils and the studied probe lengths. The proposed TDR system estimated the clay-soil water content with mean relative error of 6.6%, for the 0.30 m probe.

Racionalização do uso de força motriz em fábrica de ração

Varios paises tem utilizado a energia solar com a finalidade de reduzir a dependencia de combustiveis fosseis e as emissoes de gases de efeito estufa. Os edificios comerciais, publicos e residenciais sao responsaveis por 47,6% do consumo de energia eletrica no Brasil. O chuveiro eletrico e o equipamento com maior participacao de consumo em residencias brasileiras, seguido da geladeira e do ar-condicionado. Objetivou-se com este trabalho analisar a eficiencia energetica de um sistema solar termico com apoio eletrico para atender diferentes demandas de agua quente em uma residencia unifamiliar, comparativamente ao uso de chuveiro eletrico. No dimensionamento do sistema solar foram considerados parâmetros do Programa Brasileiro de Etiquetagem de edificios e da norma tecnica NBR 15569/2008. O aquecedor solar foi simulado pelo programa EnergyPlus nas condicoes climaticas de Vicosa, Minas Gerais. Entre outras variaveis, foram avaliadas a fracao solar do sistema, a energia transferida ao coletor solar, a energia armazenada no reservatorio termico e o consumo de energia eletrica pelas duas opcoes de aquecimento. Foi verificado que a substituicao do chuveiro eletrico pelo aquecedor solar com backup eletrico provocou uma reducao media de 70% no consumo de energia eletrica destinado a aquecimento de agua e 36% no consumo total de energia eletrica da residencia.

Metodologia de diagnóstico energético em estação de captação de água

A falta de investimento no setor energetico, aliada a sazonalidade de recursos naturais necessarios para a geracao de energia hidroeletrica, faz da racionalizacao do uso de energia eletrica uma ferramenta de apoio imprescindivel para o crescimento do Pais. A racao animal pode representar entre 70 e 80% do custo de producao da criacao de animais. Sendo assim, e importante o estudo da racionalizacao do uso de energia em processos que utilizam intensivamente forca motriz, tais como as fabricas de racao. Na fabrica de racao estudada, os motores eletricos sao utilizados principalmente para moagem e mistura de granulados e transporte. Com o objetivo de racionalizar o uso da energia eletrica, foi realizado estudo de adequacao de forca motriz dos equipamentos da fabrica de racao da Industria Pif Paf Alimentos. O indice de carregamento medio dos motores eletricos estudados foi de 48,6%. O potencial estimado total de economia com energia eletrica anual, utilizando-se sempre da melhor opcao de adequacao de forca motriz foi de R

Development of capacitive sensor for measuring soil water content

24.426,50 ao ano (23,9%). Para que essas medidas sejam efetivadas, devem-se adequar tambem: (i) as exigencias eletricas do circuito, como ajuste de reles e escolha de fusiveis; (ii) o horario de funcionamento, e (iii) necessidade de implantacao de sistema de armazenamento de racao.

Computer tools applied to analysis of solar water heaters

This study aimed to develop a methodology to diagnose energetically a water supply system for a irrigation system and for a city. The steps taken were: (i) the energy quality supplied by the utility in relation to level and unbalanced of the supplied voltage; (ii) the electrical energy consumption and demand for the pumping station; (iii) the study of the electrical and hydraulic loads characteristics; (iv) the tariff and demand contracts optimization; (v) the water storage capacity; and (vi) the working hours management. This methodology was tested and validated for the water pumping station in a town of about 70,000 inhabitants. Among the proposed actions, which saved the most, were: (i) the sizing of pumps and motors; and (ii) the optimization of tariff and demand contracts. It was noted that this methodology is simple and easy to apply and there is a great potential for saving energy up to 52%

Tarifa binômia para o custo de água pressurizada em perímetros irrigados

The irrigation management based on the monitoring of the soil water content allows for the minimization of the amount of water applied, making its use more efficient. Taking into account these aspects, in this work, a sensor for measuring the soil water content was developed to allow real time automation of irrigation systems. This way, problems affecting crop yielding such as irregularities in the time to turn on or turn off the pump, and excess or deficit of water can be solved. To develop the sensors were used stainless steel rods, resin, and insulating varnish. The sensors measuring circuit was based on a microcontroller, which gives its output signal in the digital format. The sensors were calibrated using soil of the type “Quartzarenic Neosoil”. A third order polynomial model was fitted to the experimental data between the values of water content corresponding to the field capacity and the wilting point to correlate the soil water content obtained by the oven standard method with those measured by the electronic circuit, with a coefficient of determination of 93.17%, and an accuracy in the measures of ±0.010 kg kg-1. Based on the results, it was concluded that the sensor and its implemented measuring circuit can be used in the automation process of irrigation systems.

Avaliação do deslocamento de minhocas (Eudrilus Eugeniae) submetidas a pulsos elétricos controlados

The simulation programs are important tools to analyze the different energetic alternatives, including the use of renewable energy. The objective of this study was to analyze comparatively the different computer tools available for modeling of solar water heaters. Among the main simulation software of solar thermal systems, there are: RETScreen International, EnergyPlus, TRNSYS, SolDesigner, SolarPro, e T*SOL. Among the tools mentioned, only EnergyPlus and RETScreen International are free, but they allow obtaining interesting results when applied together. The first one has a detailed module of energy analysis of solar water heaters, while the second one provides an detailed economic feasibility study and an assessment of emissions of greenhouse gases. RETScreen International and EnergyPlus programs are aimed at a diverse audience, including designers, researchers and energy planners.