IEA EBC Annex56 vision for cost effective energy and carbon emissions optimization in building renovation

Building sector has become an important target for carbon emissions reduction, energy consumption and resources depletion. Due to low rates of replacement of the existing buildings, their low energy performances are a major concern. Most of the current regulations are focused on new buildings and do not account with the several technical, functional and economic constraints that have to be faced in the renovation of existing buildings. Thus, a new methodology is proposed to be used in the decision making process for energy related building renovation, allowing finding a cost-effective balance between energy consumption, carbon emissions and overall added value

Benefits from energy related building renovation beyond costs, energy and emissions

The relevance of the building sector in the global energy use as well as in the global carbon emissions, both in the developed and developing countries, makes the improvement of the overall energy performance of existing buildings an important part of the actions to mitigate climate changes. Regardless of this potential for energy and emissions saving, large scale building renovation has been found hard to trigger, mainly because present standards are mainly focused on new buildings, not responding effectively to the numerous technical, functional and economic constraints of the existing ones. One of the common problems in the assessment of building renovation scenarios is that only energy savings and costs are normally considered, despite the fact that it has been long recognized that investment on energy efficiency and low carbon technologies yield several benefits beyond the value of saved energy which can be as important as the energy cost savings process. Based on the analysis of significant literature and several case studies, the relevance of co-benefits achieved in the renovation process is highlighted. These benefits can be felt at the building level by the owner or user (like increased user comfort, fewer problems with building physics, improved aesthetics) and should therefore be considered in the definition of the renovation measures, but also at the level of the society as a whole (like health effects, job creation, energy security, impact on climate change), and from this perspective, policy makers must be aware of the possible crossed impacts among different areas of the society for the development of public policies

Cost optimal levels for envelope components in residential building renovation – Rainha Dona Leonor neighbourhood case study

Energy Efficiency in Buildings has been gaining increasing relevance in the past decades due to the raise of the energy consumption in the building sector as a consequence of the modern way of living with higher comfort patterns. In Europe, buildings are responsible for 40% of the energy consumption, which turns them into an important target for carbon emissions’ reduction [1]. Energy efficiency should be a main concern not only in new buildings, but also in the existing ones, which have poor energy performances. In Portugal most of the building stock was built before 1990, date of entrance into force of the first thermal regulation. Therefore, most of these buildings need intervention to improve not only the living environment, but also their energy performances. To evaluate the best measures, that fulfil the minimum requirements established for the energy needs with the lowest costs, the European Commission released the Commission Delegated Regulation (EU) Nº 244/2012 that establishes a comparative methodology framework for calculating the cost-optimal level for minimum energy performance. In order to verify the renovation potential of these buildings, based on the Delegated Regulation methodology and taking advantage of a renovation process in course, a social housing neighbourhood called Rainha Dona Leonor was analysed. This analysis allowed obtaining the optimal levels for different renovations measures. The results show that it is not possible to establish a direct connection between the optimal level for the building envelope and the building as a whole, without considering the influence of the building systems

Cost optimality and nZEB target in the renovation of Portuguese building stock - Rainha Dona Leonor neighborhood case study

Improving energy efficiency in existing buildings is a great challenge. These buildings have their own limitations related with their design, location and function. To study the possibilities of cost-effectively improve the thermal performance of these buildings and increase the chances of reaching the nearly zero energy (nZEB) target, one building of Rainha Dona Leonor neighborhood has been analyzed. The purpose of the study was to find the most cost-effective renovation solution for this case study and assess in what way this solution contributes to reaching the nZEB target. With this work it was possible to understand that the energy performance of this kind of buildings can be firstly improved through renovation measures applied to the envelope but, above a certain level, changing the existing equipment and the energy source become more cost-effective

Cost optimal building renovation with a net zero energy target for the Portuguese single-family building stock built before 1960

Cost Optimality and nearly Zero Energy Buildings (nZEB) are two fundamental concepts within the current European Union policy related to the energy performance of buildings and consequently related to climate change mitigation and non-renewable resources con-sumption. While Cost Optimality is mainly focused on costs, nZEB are focused on low energy consumption levels and on site renewables harvesting. If the differences between Cost Optimality and nZEB approaches result in major differences in the selection of the best package of renovation measures, the transition from the Cost Optimal concept to nZEB might result incompatible. In this context, using a virtual building representing the Portuguese residential building stock from the 20th century prior to 1960, this study investigates the most cost-effective packages of renovation measures to achieve a zero energy balance building and compares these packages with those resulting from the calculation of cost-optimal levels. Investigating the trade-offs between a renovation towards zero energy balance and a cost optimal renovation without the use of renewables is relevant to achieve a smooth transition from Cost Optimal levels to nearly Zero Energy Buildings

Reabilitação energética do Parque Residencial: metodologia para determinação de soluções de custo ótimo

O sector dos edifícios é um dos maiores consumidores de energia a nível global e consequentemente representa um forte contributo para as emissões de gases com efeito de estufa, pelo que a redução desse consumo bem como a utilização de energia proveniente de fontes renováveis constituem neste sector medidas importantes e necessárias para mitigar os efeitos das alterações climáticas. Essa redução terá de incidir sobre os edifícios existentes quando sujeitos a obras de reabilitação, uma vez que apenas com a atuação sobre os edifícios novos, levaria demasiado tempo até se obterem impactos relevantes face ao reduzido ritmo de substituição do parque edificado. A concretização do potencial de poupança de energia nos edifícios existentes depende da combinação de medidas de eficiência energética e de geração de energia de fontes renováveis que, para além de garantirem os objectivos energéticos e ambientais estabelecidos, o consigam com o melhor compromisso entre o custo de investimento e o custo de utilização do edifício ao longo do seu tempo de vida. O presente artigo apresenta uma metodologia para a determinação das soluções de reabilitação de custo ótimo, ou seja, das soluções que apresentem o menor custo considerando o investimento na operação de reabilitação e os custos de utilização do edifício ao longo do seu ciclo de vida, e demonstra a aplicação dessa metodologia num edifício residencial característico do parque edificado de Portugal

Improving buildings energy performance: comparison between simple payback period and life cycle costs analysis

The building sector is one of the Europeâ s main energy consumer, making buildings an important target for a wiser energy use, improving indoor comfort conditions and reducing the energy consumption. To achieve the European Union targets for energy consumption and carbon reductions it is crucial to act in new, but also in existing buildings, which constitute the majority of the building stock. In existing buildings, the significant improvement of their efficiency requires important investments. Therefore, costs are a major concern in the decision making process and the analysis of the cost effectiveness of the interventions is an important path in the guidance for the selection of the different renovation scenarios. The Portuguese thermal legislation considers the simple payback method for the calculations of the time for the return of the investment. However, this method does not take into consideration inflation, cash flows and cost of capital, as well as the future costs of energy and the building elements lifetime as it happens in a life cycle cost analysis. In order to understand the impact of the economic analysis method used in the choice of the renovation measures, a case study has been analysed using simple payback calculations and life cycle costs analysis. Overall results show that less far-reaching renovation measures are indicated when using the simple payback calculations which may be leading to solutions less cost-effective in a long run perspective

Eliminação da necessidade de sistemas activos para arrefecimento dos edifícios residenciais em Portugal

Na Europa, o uso de energia para arrefecimento dos edifícios residenciais, apesar de ainda apresentar uma relevância limitada, tem vindo a crescer nos últimos anos. Em Portugal, também corresponde a uma pequena fração do total da energia usada em edifícios residenciais, mas a expansão da instalação de sistemas técnicos para fornecer arrefecimento é esperada devido à combinação de diferentes razões. Além disso, cenários para a evolução das temperaturas durante as próximas décadas devido às mudanças climáticas indicam que Portugal será um dos países mais afetados na Europa com um aumento de 3,5 a 4 ° C na temperatura média do ar em 2080. Apesar destes dados que fomentam o crescimento contínuo da instalação de sistemas técnicos para fornecer arrefecimento, Portugal apresenta características naturais que podem ser utilizadas para evitar a sua necessidade

Energy in Buildings and Communities Programme

The aim of the report is to illustrate the application of the methodology developed within the IEA EBC Annex 56 project and present several tools available for the successive implementation of the several steps of the process. The tools include those that have been used by the participating countries in the selected case-studies and also tools that, although not being used in the IEA EBC Annex 56 project, are compatible with the developed methodology

Contributos e recomendações para a revisão da regulamentação relativa à reabilitação do edificado tendo em vista os edifícios de energia quase-nula – a visão do projeto Annex 56 da Agência Internacional de Energia

Contributos e recomendações para a revisão da regulamentação relativa à reabilitação do edificado tendo em vista os edifícios de energia quase-nula – a visão do projeto Annex 56 da Agência Internacional de Energi