Efici��ncia energ��tica em edif��cios de servi��os

A efici��ncia energ��tica em edif��cios tem sido alvo de grandes desenvolvimentos nos ��ltimos anos devido �� crescente aten����o dada a esta tem��tica, motivada entre outros factores, por raz��es econ��micas de redu����o de custos e maior consci��ncia da comunidade sobre a limita����o das fontes energ��ticas convencionais. T��m-se realizado esfor��os relativamente �� procura de solu����es em tornar os edif��cios mais eficientes do ponto de vista energ��tico, desde a fase de concep����o, de execu����o (com aplica����o de novos materiais mais sustent��veis), das t��cnicas construtivas e do desenvolvimento e aplica����o de tecnologias inovadoras ligadas ��s energias renov��veis. Na presente disserta����o aborda-se esta tem��tica com especial enfoque nos edif��cios de servi��os. Procura-se caracterizar o estado actual da efici��ncia energ��tica em Portugal, tendo como suporte a an��lise da depend��ncia energ��tica, a estrat��gia nacional delineada para a energia e a transposi����o de Directivas Europeias para a legisla����o nacional e a sua aplica����o. Foi objecto de estudo o programa levado a cabo por um grande grupo empresarial portugu��s, no ��mbito da aplicabilidade da actual legisla����o em vigor, aos seus edif��cios, culminando num caso de estudo de um grande edif��cio de servi��os com o objectivo de proceder �� sua certifica����o energ��tica. As ��ltimas tend��ncias relativamente �� melhoria da efici��ncia energ��tica nos edif��cios tamb��m foram abordadas, com especial aten����o aos sistemas de gest��o energ��tica, bem como aos NZEB (Nearly Zero Energy Buildings), em linha com a recente imposi����o legislativa pela Uni��o Europeia, em que todos os edif��cios novos at�� ao final de 2020 devem enquadrar-se neste conceito.

NZEB e os novos revestimentos

Disserta����o de natureza cient��fica para obten����o do grau de Mestre em Engenharia Civil na ��rea de Especializa����o de Edifica����es

Projecto integrado de AVAC e outras especialidades para um edif��cio com necessidades quase nulas de energia

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Mec��nica

Converg��ncia para NZEB de um edif��cio de servi��os em Faro

Disserta����o para obten����o do grau de Mestre em Engenharia Civil

Converg��ncia para NZEB de um edif��cio classificado

Disserta����o para obten����o do grau de Mestre em Engenharia Civil na ��rea de Edifica����es

NZEB: um desafio para a engenharia civil

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Civil

Reabilita����o de edif��cios com novas tend��ncias NZEB: caso de estudo: edif��cio de servi��os em Set��bal

Trabalho Final de Mestrado para obten����o do grau de Mestre em Engenharia Civil

Moradia no centro hist��rico do Montijo: reabilita����o vs constru����o nova

Disserta����o para obten����o do grau de Mestre em Engenharia Civil na ��rea de Especializa����o de Edifica����es

O impacto energ��tico e as emiss��es de CO2 dos ve��culos el��ctricos em Portugal

Para a diminui����o da depend��ncia energ��tica de Portugal face ��s importa����es de energia, a Estrat��gia Nacional para a Energia 2020 (ENE 2020) define uma aposta na produ����o de energia a partir de fontes renov��veis, na promo����o da efici��ncia energ��tica tanto nos edif��cios como nos transportes com vista a reduzir as emiss��es de gases com efeito de estufa. No campo da efici��ncia energ��tica, o ENE 2020 pretende obter uma poupan��a energ��tica de 9,8% face a valores de 2008, traduzindo-se em perto de 1800 milh��es de tep j�� em 2015. Uma das medidas passa pela aposta na mobilidade el��ctrica, onde se prev�� que os ve��culos el��ctricos possam contribuir significativamente para a redu����o do consumo de combust��vel e por conseguinte, para a redu����o das emiss��es de CO2 para a atmosfera. No entanto, esta redu����o est�� condicionada pelas fontes de energia utilizadas para o abastecimento das baterias. Neste estudo foram determinados os consumos de combust��vel e as emiss��es de CO2 de um ve��culo de combust��o interna adimensional representativo do parque autom��vel. �� tamb��m estimada a previs��o de crescimento do parque autom��vel num cen��rio "Business-as-Usual", atrav��s dos m��todos de previs��o tecnol��gica para o horizonte 2010-2030, bem como cen��rios de penetra����o de ve��culos el��ctricos para o mesmo per��odo com base no m��todo de Fisher- Pry. �� ainda analisado o impacto que a introdu����o dos ve��culos el��ctricos tem ao n��vel dos consumos de combust��vel, das emiss��es de di��xido de carbono e qual o impacto que tal medida ter�� na rede el��ctrica, nomeadamente no diagrama de carga e no n��vel de emiss��es de CO2 do Sistema Electroprodutor Nacional. Por fim, �� avaliado o impacto dos ve��culos el��ctricos no diagrama de carga di��rio portugu��s, com base em v��rios perfis de carga das baterias. A introdu����o de ve��culos el��ctricos em Portugal ter�� pouca express��o dado que, no melhor dos cen��rios haver��o somente cerca de 85 mil unidades em circula����o, no ano de 2030. Ao n��vel do consumo de combust��veis rodovi��rios, os ve��culos el��ctricos poder��o vir a reduzir o consumo de gasolina at�� 0,52% e at�� 0,27% no consumo de diesel, entre 2010 e 2030, contribuindo ligeiramente uma menor depend��ncia energ��tica externa. Ao n��vel do consumo el��ctrico, o abastecimento das baterias dos ve��culos el��ctricos representar�� at�� 0,5% do consumo el��ctrico total, sendo que parte desse abastecimento ser�� garantido atrav��s de centrais de ciclo combinado a g��s natural. Apesar da maior utiliza����o deste tipo de centrais t��rmicas para produ����o de energia, tanto para abastecimento das viaturas el��ctricas, como para o consumo em geral, verifica-se que em 2030, o n��vel de emiss��es do sistema electroprodutor ser�� cerca de 46% inferior aos n��veis registados em 2010, prevendo-se que atinja as 0,163gCO2/kWh produzido pelo Sistema Electroprodutor Nacional devido �� maior quota de produ����o das fontes de energia renov��vel, como o vento, a h��drica ou a solar.

Solid-State Bipolar Marx Converter with Output Transformer and Energy Recovery

The purpose of this paper is to present and discuss a general HV topology of the solid-state Marx modulator, for unipolar or bipolar generation connected with a step-up transformer to increase the output voltage applied to a resistive load. Due to the use of an output transformer, discussion about the reset of the transformer is made to guarantee zero average voltage applied to the primary. It is also discussed the transformer magnetizing energy recovering back to the energy storage capacitors. Simulation results for a circuit that generates 100 kV pulses using 1000 V semiconductors are presented and discussed regarding the voltage and current stress on the semiconductors and result obtained.

Micro-generation Evaluation of the Zero Emissions Technologies in the Portuguese Market

Micro-generation is the small scale production of heat and/or electricity from a low carbon source and can be a powerful driver for carbon reduction, behavior change, security of supply and economic value. The energy conversion technologies can include photovoltaic panels, micro combined heat and power, micro wind, heat pumps, solar thermal systems, fuel cells and micro hydro schemes. In this paper, a small research of the availability of the conversion apparatus and the prices for the micro wind turbines and photovoltaic systems is made and a comparison between these two technologies is performed in terms of the availability of the resource and costs. An analysis of the new legal framework published in Portugal is done to realize if the incentives to individualspsila investment in sustainable and local energy production is worth for their point of view. An economic evaluation for these alternatives, accounting with the governmentpsilas incentives should lead, in most cases, into attractive return rates for the investment. Apart from the attractiveness of the investment there are though other aspects that should be taken into account and those are the benefits that these choices have to us all. The idea is that micro-generation will not only make a significant direct contribution to carbon reduction targets, it will also trigger a multiplier effect in behavior change by engaging hearts and minds, and providing more efficient use of energy by householders. The diversified profile of power generation by micro-generators, both in terms of location and timing, should reduce the impact of intermittency or plant failures with significant gains for security of supply.

Consumer energy management system with integration of smart meters

This paper develops an energy management system with integration of smart meters for electricity consumers in a smart grid context. The integration of two types of smart meters (SM) are developed: (i) consumer owned SM and (ii) distributor owned SM. The consumer owned SM runs over a wireless platform - ZigBee protocol and the distributor owned SM uses the wired environment - ModBus protocol. The SM are connected to a SCADA system (Supervisory Control And Data Acquisition) that supervises a network of Programmable Logic Controllers (PLC). The SCADA system/PLC network integrates different types of information coming from several technologies present in modern buildings. The developed control strategy implements a hierarchical cascade controller where inner loops are performed by local PLCs, and the outer loop is managed by a centralized SCADA system, which interacts with the entire local PLC network. In order to implement advanced controllers, a communication channel was developed to allow the communication between the SCADA system and the MATLAB software. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Performance assessment of a wind energy conversion system using a hierarchical controller structure

This paper deals with a hierarchical structure composed by an event-based supervisor in a higher level and two distinct proportional integral (PI) controllers in a lower level. The controllers are applied to a variable speed wind energy conversion system with doubly-fed induction generator, namely, the fuzzy PI control and the fractional-order PI control. The event-based supervisor analyses the operation state of the wind energy conversion system among four possible operational states: park, start-up, generating or brake and sends the operation state to the controllers in the lower level. In start-up state, the controllers only act on electric torque while pitch angle is equal to zero. In generating state, the controllers must act on the pitch angle of the blades in order to maintain the electric power around the nominal value, thus ensuring that the safety conditions required for integration in the electric grid are met. Comparisons between fuzzy PI and fractional-order PI pitch controllers applied to a wind turbine benchmark model are given and simulation results by Matlab/Simulink are shown. From the results regarding the closed loop point of view, fuzzy PI controller allows a smoother response at the expense of larger number of variations of the pitch angle, implying frequent switches between operational states. On the other hand fractional-order PI controller allows an oscillatory response with less control effort, reducing switches between operational states. (C) 2015 Elsevier Ltd. All rights reserved.

Direct Power Control of Matrix Converter Based Unified Power Flow Controllers

This paper presents the Direct Power Control of Three-Phase Matrix Converters (DPC-MC) operating as Unified Power Flow Controllers (UPFC). Since matrix converters allow direct AC/AC power conversion without intermediate energy storage link, the resulting UPFC has reduced volume and cost, together with higher reliability. Theoretical principles of DPC-MC method are established based on an UPFC model, together with a new direct power control approach based on sliding mode control techniques. As a result, active and reactive power can be directly controlled by selection of an appropriate switching state of matrix converter. This new direct power control approach associated to matrix converters technology guarantees decoupled active and reactive power control, zero error tracking, fast response times and timely control actions. Simulation results show good performance of the proposed system.

Predictive Optimal Matrix Converter Control for a Dynamic Voltage Restorer with Flywheel Energy Storage

This paper presents a predictive optimal matrix converter controller for a flywheel energy storage system used as Dynamic Voltage Restorer (DVR). The flywheel energy storage device is based on a steel seamless tube mounted as a vertical axis flywheel to store kinetic energy. The motor/generator is a Permanent Magnet Synchronous Machine driven by the AC-AC Matrix Converter. The matrix control method uses a discrete-time model of the converter system to predict the expected values of the input and output currents for all the 27 possible vectors generated by the matrix converter. An optimal controller minimizes control errors using a weighted cost functional. The flywheel and control process was tested as a DVR to mitigate voltage sags and swells. Simulation results show that the DVR is able to compensate the critical load voltage without delays, voltage undershoots or overshoots, overcoming the input/output coupling of matrix converters.