Sistema automatizado para o aproveitamento de água cinza e azul, com controle de PH utilizando lógica fuzzy

Every day, water scarcity becomes a more serious problem and, directly affects global society. Studies are directed in order to raise awareness of the rational use of this natural asset that is essential to our survival. Only 0.007% of the water available in the world have easy access and can be consumed by humans, it can be found in rivers, lakes, etc... To better take advantage of the water used in homes and small businesses, reuse projects are often implemented, resulting in savings for customers of water utilities. The reuse projects involve several areas of engineering, like Environmental, Chemical, Electrical and Computer Engineering. The last two are responsible for the control of the process, which aims to make gray water (soapy water), and clear blue water (rain water), ideal for consumption, or for use in watering gardens, flushing, among others applications. Water has several features that should be taken into consideration when it comes to working its reuse. Some of the features are, turbidity, temperature, electrical conductivity and, pH. In this document there is a proposal to control the pH (potential Hydrogen) through a microcontroller, using the fuzzy logic as strategy of control. The controller was developed in the fuzzy toolbox of Matlab®

Perspectivas de inserção da energia solar fotovoltaica na geração de energia elétrica no Rio Grande do Norte

The generation of electricity in Brazil is predominantly renewable, with internal hydraulic generation being more than 70% of its energy matrix. The electricity rationing occurred in 2001 due to lack of rain, led the country to increase the participation of alternative energy sources. This need for new sources of energy makes the regional potential to be exploited, which configures the change of generation model from centralized generation to distributed generation. Among the alternative sources of energy, the solar energy is presented as very promising for Brazil, given that most of its territory is located near to the equator line, which implies days with greater number of hours of solar radiation. The state of Rio Grande do Norte (RN) has one of the highest levels of solar irradiation of the Brazilian territory, making it eligible to receive investments for the installation of photovoltaic solar plants. This thesis will present the state-of-the-art in solar photovoltaic power generation and will examine the potential for generation of solar photovoltaic power in Brazil and RN, based on solarimetrics measurements conducted by various institutions and also measurements performed in Natal, the state capital

Impacto do racionamento nos resultados das empresas concessionárias do serviço público de distribuição de energia elétrica: um estudo nas empresas privadas da Região Nordeste

This work verifies the impact caused by the Emergencial Program of Reduction of Consumption of Electric Energy (energy-rationing program) in the results of the concessionary private companies of the public service of electric energy distribution localized in the Northeast Area. As the rationing invigorated from June 2001 to February 2002, its effects are diluted in the results presented by these companies in the second semester of 2001 and first quarter of 2002, with prominence for the last quarter of 2001, when the revenue of extraordinary tariff restore was instituted by the National Agency of Electric Energy (ANEEL), consequence of the so-called General Agreement of the Electric Sector made between the federal government and the companies of the electric sector. The structure of a generic electric sector and a historical review of the Brazilian electric sector from the time it was controlled by the private enterprises, including the State control period, about 1960, and returning to the control of the private enterprises in 1990, under a new regulation structure are presented. An explanation of the models of economic regulation that Brazil used for the electric sector is made, with prominence for the price cap that is the actual effective model. The process of tariff revision foreseen in the concession contracts signed by the federal government and the concessionary companies is presented, highlighting its two stages: the tariff rebalancing that defines the new price cap and the calculation of the factor X that establishes the efficiency goals for the companies. There is made a presentation of the Emergencial Program of Reduction of Consumption of Electric Energy and of the consequent General Agreement of the Electric Sector, which created the revenue of extraordinary tariff restore. A conceptual revision on reviews is presented, regarding to concepts, accomplishment and recognition. A brief review of the six companies that made part of the worked sample is also presented. Analyzing the quarters historical review and of amount of sold energy, it was possible to conclude that the energy-rationing altered the results of the studied companies significantly and that alteration was masked by the accounting process of the revenue of extraordinary tariff restore

Energia eólica em alto mar: distribuição dos recursos e complementaridade hídrica

The stabilization of energy supply in Brazil has been a challenge for the operation of the National Interconnected System in face of hydrological and climatic variations. Thermoelectric plants have been used as an emergency source for periods of water scarcity. The utilization of fossil fuels, however, has elevated the cost of electricity. On the other hand, offshore wind energy has gained importance in the international context and is competitive enough to become a possibility for future generation in Brazil. In this scenario, the main goal of this thesis was to investigate the magnitude and distribution of offshore wind resources, and also verify the possibilities of complementing hydropower. A data series of precipitation from the Climatic Research Unit (CRU) Blended Sea Winds from the National Climatic Data Center (NCDC/NOAA) were used. According to statistical criteria, three types of complementarity were found in the Brazilian territory: hydro × hydro, wind × wind and hydro × wind. It was noted a significant complementarity between wind and hydro resources (r = -0.65), mainly for the hydrographical basins of the southeast and central regions with Northeastern Brazil winds. To refine the extrapolation of winds over the ocean, a method based on the Monin-Obukhov theory was used to model the stability of the atmospheric boundary layer. Objectively Analyzed Air-Sea Flux (OAFLUX) datasets for heat flux, temperature and humidity, and also sea level pressure data from NCEP/NCAR were used. The ETOPO1 from the National Geophysical Data Center (NGDC/NOAA) provided bathymetric data. It was found that shallow waters, between 0-20 meters, have a resource estimated at 559 GW. The contribution of wind resources to hydroelectric reservoir operation was investigated with a simplified hybrid wind-hydraulic model, and reservoir level, inflow, outflow and turbine production data. It was found that the hybrid system avoids drought periods, continuously saving water from reservoirs through wind production. Therefore, from the results obtained, it is possible to state that the good winds from the Brazilian coast can, besides diversifying the electric matrix, stabilize the hydrological fluctuations avoiding rationing and blackouts, reducing the use of thermal power plants, increasing the production cost and emission of greenhouse gases. Public policies targeted to offshore wind energy will be necessary for its full development.