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- The applicability of passive solar solutions to portuguese traditional buildingsPublication . Silva, J.A. Mendes da; Ferreira, Ana VazThis work enhances the application of a clear and concise methodology to help choosing the most accurate passive solar techniques according to local climate and its influence on construction. To carry out these goals, the analysis of concepts of fictitious temperatures, the psicrometric diagram and its relation to passive solar systems zones previously established and, finally, the constructive changes that each technique requires is needed. This last factor mentioned took into account the technological and scientific knowledge, as well as the current constructive solutions applicable in the building construction sector in Portugal. The article clears these questions from the design point of view, establishing a straight interdependence between theoretic concepts and its practical application, framed by a context of optimisation, adopting the Portuguese traditional construction as the experimental scenario.
- Built environment: the sustainability of heritagePublication . Silva, J.A. Mendes da; Ferreira, Ana VazDifferent sustainable evaluation tools can provide a way to certify the building¬¬`s performance during its life cycle: raw material depletion, production of materials and components, construction, use and demolition. In this process, several variables that analyze common components, such as the reduction of resources consume, the reuse and recycle potential, flexibility and adaptability, the pollution components generated during the process, are involved. Some examples of these tools are the systems like SBTool, BREEAM, BEE or LiderA that are used to evaluate a specific context according to specific conditions. Meanwhile, the existing evaluation systems are oriented to the building´s design phase or have under consideration patterns adapted to the 21st century reality. This work was developed due to the need to analyse and evaluate the built environment, specifically in what concerns the urban settlements in Portuguese cities, with more than three hundred years old, and that are not enclosed in the new construction’s reality - both at materials and techniques levels. The knowledge gathered about the built environment allows the creation of a sustainable grid capable of guide-lining rehabilitation actions. The evaluation of these urban areas was carried out based on an exhaustive work of collecting the building’s characteristics, in an area with around 770 buildings, allowing the creation of a built environment sustainability evaluation grid and adapted to socio, cultural, heritage, economic and environmental contexts. The grid mentioned before was designed after a set of parameters were analyzed, such as: i) the existent materials and the constructive solutions adopted; ii) the urban mesh and the meeting of the construction resources to the built environment; iii) the contemporaneous patterns and the possibilities of reusing; iv) the heritage and cultural values; v) the social and economic values. The evaluation grid presented in this work shows a set of different parameters, where the criteria that are related to the external environment are reassessed according to the existent urban possibilities and where the criteria related to internal environment are adapted to the existent spaces’ possibilities.
- Sustainability assessment of building rehabilitation actions in old urban centresPublication . Almeida, Cláudia; Ferreira, Ana Vaz; Silva, J.A. Mendes daIt is essential that the society understands the importance of sustainable development, its implication for the existing living standards and the need to implement management policies that promote sustainability. Rehabilitation assumes a fundamental role in this process; however, we are faced with the lack of specific, adequate and simplified tools for the sustainability assessment in rehabilitation actions. In this paper, the analysis of different sustainability assessment systems was conducted, comparing them in order to identify the adjustments to be made to a Portuguese model taken under consideration. Subsequently, the model was cross-checked with current European and national urban rehabilitation and regeneration policies, analysing their contribution to sustainability, in order to define the assessment criteria and create a Simplified Method for the Sustainability Assessment for rehabilitation in old urban centres, which can be a useful tool, easy to use by all actors in the process and as a way of preserving the history of this areas, and the memory of those who inhabit them. This Method considers five major areas: Water, Energy, Materials, Emissions and Cultural, Economic and Social Environments. For each of these criteria, measurement indicators and levels of assessment were settled, adjusted to the context of old urban centres.
- Sustainable heritage: analysis of bulding's thermal behaviourPublication . Ferreira, Ana Vaz; Silva, J.A. Mendes daThe energy consumption of buildings has presented a steady growth in face of the global energy consumption. This fact is related to a variety of factors, including the increased demand for comfort by the inhabitants, the low quality of construction of buildings and their inadequacy to the climatic and environmental context in which they are included. Reversing this tendency includes the necessary intervention in the built environment, promoting the attainment of comfort through interventions that respect the principles of sustainability in construction, namely in resource consumption over the building’s life cycle. Energy rehabilitation can be accomplished by enhancing the envelope’s thermal protection using strategies in terms of i) strengthening insulation in the opaque envelope; ii) strengthening insulation of the glazing and iii) control of solar gains. The use of passive solar systems and the improvement of energy systems are other approaches for improving the thermal performance of dwellings. This study examines the constructive characteristics and the pathologies found in approximately 700 buildings located in Coimbra’s downtown (“Baixa”), the historic sector of the city. From this analysis it was possible to assess the present-day performance of these buildings, attending to the existing code and the application of DesignBuilder software, and to define the desired levels of performance resulting from rehabilitation procedures. The definition of these levels allows the superintendence of the process of intervention, taking into account the solutions to adopt with regard to the principles of sustainability.
- Adapting portuguese architecture to former african colonies climate conditionsPublication . Ferreira, Ana Vaz; Silva, J.A. Mendes daThe Portuguese architecture is borderless due to the colonialism period. Many African countries can testify this influence and the cities still sprawling around remaining old buildings. These constructions are characterized by using local resources and adapting Portuguese architecture to the climatic characteristics and answering local natural hazards. The work developed presents a systematic approach about the constructive changes, identifying the solutions adopted for answering climatic demands. The passive solar systems used were categorized and some examples were selected according to examples found in African cities with Portuguese influence as Beira (Mozambique), Lubango, Namibe and Luanda (Angola) and Praia (Cape Verde). This analysis encompasses strategies to improve thermal behavior of buildings, as ventilation trough the analysis of ventilated roofs or windows geometry, shadowing devices as large eaves, brises and second facades, among other issues. The local construction was also analyzed in order to find out traditional techniques for cooling buildings in a natural way.
- Thermal characterisation of traditional wall solution of built heritage using the simple hot box-heat flow meter method: In situ measurements and numerical simulationPublication . Roque, Eduardo; Vicente, Romeu; Almeida, Ricardo M.S.F.; Silva, J.A. Mendes da; Ferreira, Ana VazImproving the thermal performance of the historic building stock has the potential to revitalise these buildings and reduce the operational energy share. To achieve that, the first requirement should be to identify and clearly characterise the building stock. However, currently, there is a lack of knowledge regarding the thermal behaviour of traditional wall solutions, and, consequently, energy auditors often use assumptions and simplifications to predict it. Wrong estimations or excessive simplifications may have a severe impact on the thermal behaviour assessment and consequently on the effectiveness of the retrofitting measures. In the scope of buildings thermal comfort and energy efficiency, the thermal resistance of both the external and internal envelope is one of the most relevant parameters for the characterisation of building elements. This work investigates the in situ thermal resistance of a traditional wall solution (“tabique” wall) of a historic building located in the north region of Portugal. The Simple Hot Box - Heat Flow Meter Method (SHB-HFM), based on the procedure described in the standard ISO 9869, is considered in the present study and its applicability to heterogeneous traditional wall solutions is discussed. The importance of controlling the radiative part of the heat transfer onto the measuring sensors is highlighted, and new development to the method is proposed in this paper via the introduction of a baffle inside the SHB. Furthermore, a finite element computer model of the case study was developed in order to ensure that some important premises allowing improving the accuracy of the final results were achieved during the measurement period as well as to enhance the robustness of the obtained conclusions. The achieved results contribute to explore the applicability of the SHB-HFM to highly heterogeneous constructive solutions present in historic buildings, where the traditional HFM method may not be applicable. In addition, this research also aims to better understand the thermal behaviour of “tabique” walls, upon which the available information is scarce. The experimental measurements and numerical simulation results present a good agreement, and an R-value of 0.56 m2 °C W−1 is measured and computed.
- Comparison between codes for building's thermal behaviour: Brazil and PortugalPublication . Ferreira, Ana Vaz; Silva, J.A. Mendes da; Romeiro, NatáliaResumo O presente artigo tem como objetivo analisar as limitações presentes nas normas brasileiras através da comparação com a regulamentação portuguesa e destacar possíveis propostas que possam contribuir ara uma metodologia mais exigente. Como estudo de caso, selecionou uma residência, com os padrões construtivos definidos no Programa Minha Casa, Minha Vida (PMCMV), para três cidades brasileiras com zonas bioclimáticas distintas e com isso, analisou os resultados obtidos através das seguintes metodologias: i) do método simplificado da norma brasileira NBR 15575; ii) do método prescritivo do RTQ-R; iii) do programa informático Design Builder. Através das análises dos resultados e da comparação com a metodologia da regulamentação portuguesa (REH), identificou as principais limitações que constam nas normas, como também os elementos que construtivos com maior influência nos ganhos e perdas de calor da edificação. Dessa forma, foi possível concluir que a metodologia prescritiva das normas brasileiras restringe a análise dos elementos de paredes e cobertura, ignorando o contributo pelos vãos envidraçados, assim como apresenta valores limites e metodologias diferenciadas para os mesmos parâmetros de avaliação entre as normas, o que podem conduzir a interpretações diversas. Visto que as normas já apresentam uma estruturação com base relativamente adequada, a incorporação das propostas na regulamentação surge como contribuição viável para uma metodologia mais exigente, ao valorizar os elementos construtivos determinantes ao edifício.
- Thermal code evolution and its contribution to the sustainable constructionPublication . Ferreira, Ana Vaz; Silva, J.A. Mendes daIn this paper it was analysed the evolution of the Portuguese Thermal Code in of face of sustainable parameters. The two versions were applied to the same housing building in two different positions in a way to improve the solar gains and be able to compare the results. The results gotten from the former steps were analysed, as well as the main differences noted between the two versions of the Codes. The calculus method pursued in the second version is similar to the first one, due to the technicians applying familiarity, but inserting new parameters and more demanding values. Considering that the new construction exigencies, highly concerned with sustainable constructive principles and environment-responsive attitudes, a set of the main factors to take under consideration in face of the more recognized sustainable construction methodologies is presented. The final stages of the paper focus the assessment of the collected results of the two versions of the Code, relating them with the sustainable construction criteria. These parameters allow outlining an overview about the Code evolution and its contribution to the improvement of the housing sector, in terms of the sustainable development.
- The accomplishment of portuguese thermal code exigencies in old housing buildings’ interventionsPublication . Ferreira, Ana Vaz; Silva, J.A. Mendes daThe energetic certification system was implemented in Portugal in 2006, with repercussion after 2008, and motivated by the transposition of European Energy Performance Building Directive (EPBD) from 2002. The system was reviewed in 2013, after the EPBD recast in 2010. The new legislation came up with restrictive parameters in terms of constructive solutions in order to decrease the energetic consume and Greenhouse Gas Emissions (GGE) from built environment. These parameters, such as U-values for example, are presented through reference and maximum values, and is mandatory that the analyzed building present a nominal cooling and heating needs inferior than a reference building. The thermal code is not mandatory for some buildings, considering some specific characteristics, and are an exception to the norm. It is possible not to apply it in the situation when the code compromises traditional buildings in terms of architectural value and/or patrimonial interest. The aim of this work focused on the analysis of some interventions, the existent solutions and the intervention actions, in old buildings where the thermal code was not applied. These data were compared with the thermal code exigencies in order to understand what extra efforts are required in order to accomplish the reference values and its implications in buildings architectural characteristics as well as its impact in patrimonial relevance and value.
- Building's rehabilitation towards sustainable behaviourPublication . Silva, J.A. Mendes da; Ferreira, Ana VazTo achieve a sustainable building’s behaviour and preserve the environmental balance, three laws must be taken into account: (i) the resources’ consume must not be faster than the rate at which nature can restock them, (ii) the creation of systems that consume maximum energy-quality and (iii) the maximization of the use of renewable and recycled materials. Therefore, the buildings’ rehabilitation process must increase, instead of the proliferation of new buildings, in order to provide the sustainability of the built environment and minimize its ecological impact. The sustainable rehabilitation process is even more difficult in historical areas, in general sited in central zones of the urban mesh, with fragile comfort conditions and a rigid structure. In this paper, different evaluation tools for sustainable buildings were analysed in order to provide a set of evaluation criteria to be applied in the rehabilitation process in historical zones.