Assessement of the Portuguese building thermal code: Newly revised requirements for cooling energy needs used to prevent the overheating of buildings in the summer

In this paper, cooling energy needs are calculated by the steady-state methodology of the Portuguese building thermal code. After the first period of building code implementation, re-evaluation according to EN ISO 13790 is recommended in order to compare results with the dynamic simulation results. From these analyses, a newly revised methodology arises including a few corrections in procedure. This iterative result is sufficiently accurate to calculate the building’s cooling energy needs. Secondly, results show that the required conditions are insufficient to prevent overheating. The use of the gain utilization factor as an overheating risk index is suggested, according to an adaptive comfort protocol, and is integrated in the method used to calculate the maximum value for cooling energy needs. This proposed streamlined method depends on reference values: window-to-floor area ratio, window shading g-value, integrated solar radiation and gain utilization factor, which leads to threshold values significantly below the ones currently used. These revised requirements are more restrictive and, therefore, will act to improve a building’s thermal performance during summer. As a rule of thumb applied for Portuguese climates, the reference gain utilization factor should assume a minimum value of 0.8 for a latitude angle range of 40-41ºN, 0.6 for 38-39ºN and 0.5 for 37ºN

Energy performance certificate: a valuable tool for building-to-grid interaction?

New challenges were opened with the recast of Energy Performance of Buildings Directive, requiring by 2020 that new buildings be “nearly Zero-Energy Buildings” (nearly ZEB). In addition to consumer buildings, Net ZEBs are also producers’ by using as much renewable energy sources as possible to compensate the building energy load. Sustainable cities require energy-efficient buildings, i.e. buildings where the use of energy is minimized without compromising the occupants comfort, namely for heating, cooling, lighting and indoor air quality. But smart cities require energy-efficient ‘interactive’ buildings, which integrate multiplecarrier energy networks and provide up-to-date valuable information for their management, where buildings are simplified to single nodes characterized by their energy load, generation, storage and conversion, applying the load-generation approach. The information currently available in the Energy Performance Certificate is not relevant for estimating the time dependent building energy load, but it can be easily improved by including a few descriptive parameters

Inclusão de um aluno com perturbação do espectro do autismo na sala de aula

Esta comunicación presenta un proyecto de intervención que incluye una reflexión teórica y una parte práctica sobre la inclusión en el aula de un estudiante con trastorno del espectro autista. El mundo de los niños autistas y sus familias inquieta a los profesionales de la educación. Se mira a este mundo como un todo, no sólo se interpretan los intereses, las necesidades, capacidades y ritmos de aprendizaje, sino también el reflejo en el contexto familiar y educativo. " Vivir con autismo es una abdicación de una forma de ver el mundo, es recorrer los caminos que nos llevan a más de una manera de ver el mismo mundo, es, sin duda, hablar y escuchar otro idioma!" (Cavaco, 2009 p.129). El sistema educativo portugués, comprometido con satisfacer las necesidades específicas de los niños y jóvenes con trastorno autista, está diseñado para crear un marco legal que permita a las unidades más nuevas estructuradas de enseñanza, a través de metodologías de intervención adecuadas, áreas de poder y capacidad de compromiso. En este contexto, es nuestra intención presentar parte de los resultados del proyecto de intervención de la incorporación de un estudiante con trastorno del espectro autista en la educación reglada.This communication presents an intervention project that includes a theoretical reflection and a practical part on the inclusion in the classroom of a student with an autism spectrum disorder. The world of the autistic children and their families are concerned about the education professionals. Looking at this world as a whole, not only are interpreted the interests, needs, abilities and learning rhythms, but also the reflection in the family and educational context. "Living with autism is an abdication of a way of viewing the world, is to walk the paths that lead us to more than one way to see the same world, it is, without doubt, to talk about and hear another language'" (Cavaco, 2009 p129). The Portuguese educational system, committed to meet the specific needs of children and young people with autistic disorder, is designed to create a legal framework that would allow the newer units structured teaching, through appropriate intervention methodologies, areas of power and capacity for commitment. In this context, it is our intent to present part of the results of the intervention project for the incorporation of a student with an autism spectrum disorder in formal education.O presente comunicação propõe-se apresentar um projeto de intervenção que envolveu uma reflexão teórica e uma componente prática sobre a inclusão na sala de aula regular de um aluno com Perturbação do Espectro do Autismo. O mundo da criança autista inquieta profissionais de educação e pais. Olhar para este mundo como um todo, não é só interpretar interesses, necessidades, capacidades e ritmos de aprendizagem, é, também, olhar reflexivamente para o contexto familiar e educacional. “Conviver com o autismo é abdicar de uma só forma de ver o mundo, é percorrer caminhos que nos conduzem a uma múltipla forma de ver esse mesmo mundo, é, sem dúvida, falar e ouvir uma outra linguagem!” (Cavaco, 2009, p.129) O Sistema Educativo Português, empenhado em responder às necessidades específicas das crianças e jovens com Perturbação Autista, concebeu um enquadramento legal permitindo criar as recentes unidades de ensino estruturado, que através de metodologias de intervenção adequadas, potencia as áreas e capacidades comprometidas. Neste contexto é nossa intenção apresentar parte dos resultados do projeto de intervenção da inclusão de um aluno com Perturbação do Espectro do Autismo no ensino regular.peerReviewe

Solar XXI building: Proof of concept or a concept to be proved?

Solar XXI building is a low energy office building where passive and active solar strategies have been applied to reduce the use of energy for heating,cooling and lighting, combining also an extensive photovoltaic façade for electricity production. Solar XXI opened in 2006 and is considered a high efficient building, close to a net zero energy building (NZEB), where the difference between the energy consumed and that produced is 1/10th of the energy consumed by a Portuguese standard new office building. Its design includes many energy efficiency concepts, such as a high insulated envelope,south sun exposure, windows external shading, photovoltaic panels heat recovery,ground-cooling system, daylighting, stack effect and cross ventilation. The solar gains of the windows and the effectiveness of shading devices were evaluated in order to correlate solar radiation, external and indoor air temperatures.It was also verified that amplitude-dampening of ground cooled air ranged between 5 and 8 C, following the trend of the analytical solution for heat diffusion of a cylindrical air/soil heat-exchanger

Methodological development of sesonal cooling energy needs by introducing ground-cooling systems

In past years, building professionals increased their interest on passive systems as sustainable solutions to reduce energy needs. This has been driven by the building certification program and new Portuguese building thermal code enacted in 2006. For residential and small office buildings, the methodology adopted is a seasonal quasi-stationary approach for calculating cooling energy following EN ISO 13790:2007. However, this method lacks specific recommendations for accounting passive cooling systems, namely ground-cooling systems. In this paper, the ground-heat exchanger contribution is included in the energy needs method. This development is sustained by measurements obtained in the ground-heat exchanger running on Solar XXI office building at LNEG campus, complemented by simplified and Fourier theoretical formulations. The horizontal ground-heat exchanger at Solar XXI is constituted by 32 concrete ducts, with a 30 cm diameter and buried 4.6 m deep. The air entrance is made from a feeding well about 15 m away from the building and its functioning during summer warm days supplies cool air for room offices

Insights into Single Droplet Impact Models upon Liquid Films Using Alternative Fuels for Aero-Engines

In aero-engines, the introduction of biofuels is among the best alternatives to fossil fuels, and this change is likely to affect the impact of droplets on interposed surfaces. Under this framework, this work reviews the main morphological hydrodynamic structures occurring upon the impact of a liquid droplet on a wetted surface, using jet fuel and biofuel mixtures as alternative fuels. The experiments performed allow investigating the effect of the liquid film thickness on the dynamic behavior of single drop impact, considering the relevancy of these phenomena to the optimization of engine operating parameters. Particular emphasis is given to the occurrence of crown splash, and the morphological differences in the outcomes of drop impact depending on the impact conditions and fluid properties. The four fluids tested included pure water (as reference), 100% Jet A-1, 75%/25%, and 50%/50% mixtures of Jet A-1 and NExBTL (Neste Renewable Diesel)—with the Weber impact number between 103 and 1625; Reynolds values 1411–16,889; and dimensionless film thicknesses of δ = 0.1, 0.5, and 1. The analysis on the secondary atomization for the different fluids evidences the predominance of prompt and crown splash, and jetting for alternative fuels. Finally, besides a systematic review of empirical correlations for the transition to splash, we investigate their universality by extrapolating the validation range to evaluate their ability to predict the outcome of impact accurately. One of the correlations studied show the highest degree of universality for the current experimental conditions, despite its limitation to thin liquid films (δ=0.1).Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

O movimento associativo de pais: uma participação activa e democrática na escola

[Resumo] Em Portugal, o Modelo de Gestao do Ensino Básico contempla a participação das Associações de Pais e Encarregados de Educa<;ao nos Órgaos de Gestao. A autonomia traduz-se na verdadeira participação na vida escolar de Professores, alunos, funcionários, pais e representantes da comunidade circundante. O direito e o dever da participação dos pais na escola passa pela fomentação de relaçoes de trabalho e de entreajuda para a construção de urna educação partilhada por todos os agentes educativos na construção de urna sociedade livre e democrática. O desenvolvimento do Movimento Associativo cresceu sempre afrente da lei, surgindo esta depois a regulamentar as experiencias reais que aqui e além iam aparecendo. No entanto, a legislaçã ao produzida nao representa ainda a esperada mudança de mentalidades e atitudes dos educadores face aescola dos seus educandos. Em causa está agora, muito mais do que o tradicional trabalho das associaçoes, a fomentar a Escola de Pais. Novos desafios foram propostos com o novo diploma que regulamenta o Regime de Autonomia, Administração e Gestao dos Estabelecimentos de Ensino. É neste contexto que efectuámos um estudo em que utilizámos, como instrumento de recolha de dados, um Inquérito por Questionário cujo objectivo é saber como é percepcionado o papel das Associação de Pais, nas escolas do distrito de Coimbr

Air flow exchange velocity of urban canyon cavities due to thermal spatial differences

In this paper, the air exchange velocity between the urban canyon cavity and the air layer above roof level is quantified, using a two-dimensional k-ε model, and correlated with the air cavity mean temperature, for two cases: leeward and downward wall heating. The spatial thermal differences are evaluated by assuming a wall temperature higher than the air temperature, with this difference ranging between 0 and 16 K. The undisturbed wind velocity above the roof level is varied from 1 to 6 ms-1 and the canyon aspect ratio is 1.5, which corresponds to a skimming flow regime. The model predicts two situations, which correspond to air flow regimes where one or two eddies are formed, respectively: (a) for high wind speed, the air inside the cavity is negligible affect by the buoyancy effect and the air exchange velocity linearly increases with the increase of wind velocity; (b) for low wind speed, when the buoyancy forces are stronger than the wind induced forces, the air exchange velocity is not a linear function with the wind velocity. The transition wind velocity between (a) and (b) is a function of the wall-air temperature difference. The situation of windward heated wall and two eddies air flow regime is the most favorable to extract heat from the cavity. On the contrary, the heated air is hardly extracted from the cavity when only the wind induced eddy is predicted and windward wall is heated. In this situation an increase of 10 K on the wall temperature increases by 1 K the in-cavity air temperature

Eficiência energética na cidade: Estratégias para a promoção da capacidade natural de aquecimento e arrefecimento de edifícios

Este estudo apresenta uma técnica para, a partir de um dado índice de construção, encontrar as formas urbanas mais favoráveis ao desempenho térmico de edifícios, com base na absorptância efectiva do edifício no Inverno e no Verão. Esse parâmetro é indicativo da exposição solar do mesmo e da capacidade natural de aquecimento de um edifício quando esse se encontra inserido numa malha urbana. A avaliação da absorptância efectiva para as duas estações do ano permitiu encontrar as formas de organização da malha que beneficiam a acessibilidade solar de Inverno, mas restrigem-na no Verão. Para o cálculo da absorptância efectiva utiliza-se o Método das Matrizes Urbanas que consiste em obter para cada geometria, uma matriz Ψ que descreve a forma como a radiação que incide em cada uma das parcelas que compõem as superfícies do bloco urbano se distribui pelas restantes superfícies. Essa matriz integra os factores de forma entre as superfícies e as respectivas propriedades de absorpção considerando, dessa forma, as reflexões múltiplas que ocorrem no interior do espaço urbano. A aplicação de uma metodologia de optimização a diversas formas urbanas, com base no conceito de algoritmo genético, permitiu concluir que, para as latitudes de 37º e 42º, as malhas urbanas mais favoráveis são os blocos de secção rectangular, com 3 a 5 pisos, dispostos segundo um eixo Este-Oeste por forma a possuirem uma maior fachada exposta a Sul. O espaçamento entre blocos é sempre maximizado na direcção Norte-Sul por forma a permitir, no Inverno, uma maior exposição solar da fachada Sul e, por outro lado, minimizando o espaçamento entre blocos na direcção Este-Oeste, prevenir os excessivos ganhos solares na estação de Verão. Para uma latitude de 37º são ainda soluções blocos de secção quadrangular com 5 a 8 pisos, que formam uma malha com ângulo de ±15º relativamente à direcção dos pontos cardeais