Improving buildings refurbishment through operative conditions evaluation

As EU existing buildings stock account for 40% of the total energy consumption, it is important to take measures to reduce these needs and, consequently, reduce the EU external energy dependency as well as reducing the greenhouse gas emissions, in accordance with what is prescribed in the EU Directive 2002/91/EU on Energy Efficiency in Buildings (EPBD) and reinforced with the "EPBD-recast". The implementation of energy efficiency measures in the existing building stock is necessary to meet the 2020 targets. Thus, energy refurbishment of existing buildings is essential to achieve these goals. However, during the buildings refurbishment, energy issues should not be the only concerns since the indoor air quality is also as important. When planning a building refurbishment it is then necessary to take into account the energy efficiency exigencies and also the indoor air quality. To do so, the main problems of the existing buildings should be identified, in order to do the right choices regarding the refurbishment project. This work presents a study carried out in a large office building to identify the main pathologies, related to the energy efficiency and also to the indoor air quality. The study encompasses an “in-situ” evaluation of the operating conditions, indoor air quality and air change rate. The main objective of this study was to support the development of a refurbishment project of the building that can optimize the energy efficiency, but also the relevant parameters to the Indoor Air Quality. The results showed that the building has a poor envelope thermal resistance, inadequate shading systems and also several problems regarding high concentration of some pollutants like CO2 or VOC

Portuguese EPBD based regulation put side by side with energy simulation tools

In 2002 EU implemented the Energy Performance of Buildings Directive which led to the revision of the buildings thermal codes. The transposition of EBPD into the Portuguese legislation was made through three regulations: RCCTE for residential buildings, RSECE for office buildings and SCE that establishes the energy labelling system. The national code RCCTE sets two methodologies for assessing the energy performance of buildings: a simplified methodology and a more detailed one, depending if it is an existent or a new building. It has been observed that since the entrance into force of these codes, the project teams are using the RCCTE methodologies as tools to estimate the energy consumption of buildings. In this work it was tested the accuracy of this approach, performing two studies: one where the energy needs obtained with the RCCTE methodology were compared with the ones obtained with a dynamic simulation tool; and another where the same energy needs were compared with the ones obtained with a simplified RCCTE methodology foreseen for existing buildings. With the studies performed it was verified that the RCCTE methodology is accurate enough, except for the coldest regions, where another kind of tool should be applied. The simplified methodology showed inaccurate results and must be used with caution. However, with some corrections, important improvements can be achieved

Definition of the energy performance requirements in rehabilitation projects

Building rehabilitation is essential to achieve the targets defined by the EPBD-recast regarding energy efficiency, reduction of carbon emissions and use of on-site renewable energy sources. To propose an effective building rehabilitation it is necessary to study the best combination of available options in terms of construction solutions, technical building systems (hot water, ventilation, heating, cooling and lighting), their cost, but also their impact on the thermal and acoustic comfort and indoor air quality of the building. Also, the definition of the cost-optimal level is essential, which is the minimum lifecycle cost (including investment costs, maintenance and operating costs, energy costs, earnings from energy produced and disposal costs) of each individual measure. In this work the multi-criteria decision analysis method ELECTRE III will be applied to balance all these aspects, during the design phase of a refurbishment project, in order to assist the design team on the selection of construction solutions and technical building systems. A simple case study is presented to demonstrate the feasibility of this approach in what concerns the definition of the energy performance requirements (e.g. thickness of insulation and efficiency of the heating system/air-conditioning system etc.), of a rehabilitation project. In this example several retrofit alternatives were studied, their implementation could lead to the reduction of the energy needs of the building from 13% to 83%. With this approach it was also possible to identify the alternative with the best global performance considering the investment costs, energy needs, indoor air quality, thermal comfort, and CO2 emissions

Módulo inovador para a reabilitação energética

A reabilitação energética dos edifícios é uma área com crescente importância para o setor da construção Portuguesa. Tal deve-se a uma conjugação de diversos fatores, desde o estado de degradação e fraco desempenho energético dos mesmos, até à drástica redução do índice de construção nova. Como tal, de modo a adequar o parque habitacional existente às novas necessidades, mas também às mais recentes exigências por parte dos moradores, são fundamentais extensas intervenções de reabilitação no parque habitacional, procurando dotar o mesmo de uma maior eficiência energética, possibilitando assim garantir o conforto térmico dos ocupantes sem um gasto energético excessivo. No entanto, é necessário desenvolver novas soluções de reabilitação para introdução no mercado, as quais devem ser projetadas, não só para aumentar o desempenho térmico da envolvente mas também possuir maior viabilidade económica, serem fáceis de aplicar, garantirem menores tempos de aplicação, assegurarem um controlo de qualidade na sua execução e mostrarem algumas preocupações ambientais na seleção dos materiais. Com estes objetivos em perspetiva, o Laboratório de Física e Tecnologia das Construção da Universidade do Minho desenvolveu uma solução de reabilitação prefabricada para aplicação em fachadas de edifícios existentes otimizada em termos da relação custo / benefício

Sustainable test cell : performance evaluation

Energy is one of the main causes of the environmental pollution. In the European Union, buildings are responsible for 40% of the final energy demand and 1/3 of the emissions of greenhouse gases. Therefore, in order to promote the energy consumption reduction, it is fundamental to employ sustainable development principles in the construction sector. In order to demonstrate and show the potentialities of Sustainable building technologies two Test Cells were built. Comparing the solutions obtained via “in-situ” measurements and energy simulation tools, it was verified that the new Sustainable solution has a better energetic and environmental performance.(undefined

Comparative study of comfort indicators for school constructions in sustainability methodologies: schools in the amazon and the southeast region of Brazil

In the 1970s and 1980s, the effects of pollution in the atmosphere grew from a local to a global scale, affecting the entire planet. Consequently, economic and social issues began to be increasingly more connected with environmental protection. Several measures were taken towards environmental preservation, many of those related to the sustainable construction of buildings. This work intended to make a parallel between comfort indicators among different schools in Brazil, beginning with the specific analyses of schools in Juiz de Fora (Minas Gerais, MG), in the Southeast region, and in Macapá (Amapa, AP), in the Amazon or Northern region. This comparison between schools is made to demonstrate the need to adapt methodologies and certifications that promote sustainability in school buildings for each region of Brazil. Questionnaires about ergonomic, thermal, visual and acoustic comfort, and air quality, were applied in two high-school buildings in Juiz de Fora, Academia School and Santa Catarina School, and in two high schools in Macapá, Tiradentes School and Professor Gabriel Almeida Café school, to understand the difference between these two regions of Brazil regarding comfort conditions. A comparison between the results of the four schools was made, proving the necessity of the elaboration of a specific methodology for each Brazilian region.The authors wish to thank Parque Escolar Company (EPE) for providing all material necessaryfor the execution of the article; and Abílio Ferreira, the managing director of Francisco de Holanda SecondarySchool, for showing the school and providing necessary information

Portuguese building stock indoor environmental quality “in-situ” assessment

Since the implementation of the Energy Performance of Building Directive, EPBD, in general, and the entrance into force of the respective Portuguese codes, in particular, buildings are requested to have better energy performances. However, during the buildings performance evaluation, energy issues should not be the only concerns since the indoor environmental quality is also as important. Thus, in this paper it is presented an “in-situ” evaluation of the Portuguese building stock regarding several parameters related to indoor environmental quality (IEQ), envelope thermal quality and operating conditions, natural illumination levels, thermal and acoustic comfort and indoor air quality. During the measurement campaign were evaluated several buildings that encompass different types of construction solutions, climatic zones and construction periods. One of the major objectives of this study was to support the development of building solutions that can optimize all the relevant parameters to the IEQ. Another important objective is the dissemination of the results through public entities, such as construction companies and design teams in order to influence the buildings projects to include other parameters than energy during the design process. Even though the measuring campaign is still in progress, there are already some preliminary results that show that, in average, the Portuguese buildings have a poor envelope thermal resistance, untreated thermal bridges, unsuitable natural illumination levels, several problems regarding high concentration of some pollutants like CO2 or VOC and also problems with acoustic discomfort due to an inadequate sound insulation

Research on the Portuguese building stock and its impacts on energy consumption – an average u-value approach

The article aims to evaluate the Portuguese building stock energy policies and strategy for energy saving in buildings among the EU members. It was found out the average heat transfer coefficients of the main structural elements of Portuguese Buildings and analyzed the U-values of this elements considering different time periods. The fundamentals of this study were funded by the Agency for Development and Innovation (ADI) and co-financed by the European Regional Development Fund (FEDER) through the Operational Program for Competitiveness Factors (POFC) assigned to the Building Physics and Construction Technology Laboratory with the reference SB Tool SPT_2011_4

Synthesis and thermal behaviour of an amorphous solid polymer electrolyte

In this study the synthesis of an amorphous polymer network, poly[oxymethylene-oligo(oxyethylene)], designated as aPEO, is described. This polymer has been characterized by gel permeation chromatography, thermal analysis, conductivity measurements, evaluation of electrochemical stability and nuclear magnetic resonance spectroscopy. The synthetic procedure developed permits partial fractionation of the product of the polymerization reaction. This linear macromolecule appears to be a promising polymer for application in batteries and electrochromic devices since it provides access to an amorphous polymer structure with good mechanical properties and promising electrochemical behavior.Fundação para a Ciência e a Tecnologia (FCT