• Energy Research

Assessing singular elements that constitute the air barrier of a building envelope is quite unfeasible in Life Cycle Assessment (LCA). The study of these solutions through this particular scope is often overlooked. Two major aspects contribute to it: the complexity of the relationships between elements and the reduced embodied impact of these materials in the overall construction or retrofitting works. This work uses LCA and Life Cycle Costing (LCC) to study the viability of applying two envelope air barrier solutions in dwellings with excessive air change rates and equipped with different heating systems. The application of air barrier solutions resulted in average energy consumption savings in urban terrain, almost half of those in rural terrain during the heating season. Environmental performance and life cycle costs revealed mechanically (MECH) fastened air barriers to outperform fluid (FLUID) applied ones. The median annualized cost of adopting a FLUID solution was almost four times that of a MECH solution. Dwellings equipped with electric radiators ranked first in the shortest average Energy Payback Period (EPP) and the highest average Reference Service Life (RSL) savings. With the current analysis, the adoption of MECH solutions is recommended, independently of the heating system the dwelling is equipped with. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Abstract Due to the time-consuming and complicated process of performing Building Sustainability Assessment (BSA), this is usually incompatible with construction companies’ deadlines. With the emergence of Building Information Modelling (BIM) in the construction industry, the opportunity for BSA methods to adopt and benefit from BIM arises. Following a previous study, this paper aims to put in practice a proposed theoretical approach to facilitate the implementation of the BSA since the preliminary design stages using, as an example, the Portuguese SBToolPT-H method. Therefore, this paper analyses how BIM platforms can contribute to optimising the BSA evaluation. To achieve this goal, a case study was modelled and characterised in Autodesk Revit and, tailored parameters were created to support the assessment. The results show that Autodesk Revit can support the evaluation of 13 SBToolPT-H sustainability criteria, in a faster and automated way when faced with the traditional assessment process. The capabilities of BIM platforms and its wider use by designers can significantly contribute to the integration of BSA methods in the BIM collaborative process, thus contributing to a more sustainable built environment.

Buildings are responsible for several negative impacts on the environment, most of them related to nonrenewable energy consumption, increasing the concern regarding buildings energy efficiency. In this context, computer software has been used to estimate the energy needs of the built environment, and the Building Information Modelling (BIM) methodology can be used to simplify this process. This study aims to validate a BIM-based framework to streamline the energy analysis of Portuguese buildings, based on the method of the national regulation for the thermal performance of residential buildings. Currently, designers need to spend considerable time assessing all the building characteristics and performing the mandatory calculations for energy performance analysis. It is also intended to link the results of the energy simulation with a Building Sustainability Assessment method—SBToolPT-H. The purpose is to demonstrate how it is possible to benefit from this approach to simultaneously improve building sustainability during the design stage. To do so, different case studies were modelled in Autodesk Revit and exported to a BIM energy tool to perform energy simulation analysis. The results were validated against the official assessment method of the Portuguese thermal regulation and were successfully used to assess the SBToolPT-H energy efficiency category. The research outcomes provide design teams with a reliable BIM-based framework to improve building energy performance and to develop thermal projects while enhancing building sustainability. It also increases the knowledge about the integration of sustainability assessment in the BIM environment, providing new insights for complete integration.

Knowing the properties of vernacular materials is crucial to heritage conservation and to develop innovative solutions. Reed, considered to be a carbon-neutral and a carbon dioxide sink material, has been used for centuries for diverse uses. Its high availability and properties made it a popular building material, including in Portuguese vernacular architecture. An experimental investigation was conducted to evaluate the physical performance, thermal performance, and durability of the reed found in Portugal since the characterisation of this material was not found in previous studies. The influence of geometric characteristics and the presence of nodes on these properties were also analysed, and the results showed that they are irrelevant. The studied reeds were found to have an adequate thermal performance to be used as thermal insulation. Their thermal resistance (1.8 m2·°C/W) and thermal conductivity (0.06 W/m·°C) are under the requirements defined by Portuguese regulations on thermal insulation materials. Overall, the physical characteristics (moisture content, density, and retraction) are compatible to its use in the construction. Concerning durability, there was only a trend for mould growth in particular environments. The results provide valuable data to be considered in the development of new construction products based on this natural and renewable material. Additionally, considering the studied samples, the reed found in Portugal has characteristics suitable for use as a building material, especially as a thermal insulation material.

It is increasingly recognised that the energy renovation of the existing building stock will be determinant for achieving 2030 and 2050 decarbonisation targets in Europe. As operational energy is being dramatically reduced through regulatory efforts and funding from the European Union, the relevance of the environmental performance of these interventions becomes higher, namely regarding embodied energy and carbon emissions associated with the materials that compose the renovation solutions. Although some studies address these impacts in buildings, the range of studies focusing on the neighbourhood scale is limited. This article presents a methodological framework combining a life cycle cost assessment (LCC) and a life cycle assessment (LCA). The purpose is to assess the relevance of embodied energy and carbon emissions on the cost-effectiveness of building renovation solutions towards nZEB at the neighbourhood scale by comparing an operational energy approach and a whole life cycle approach in a case study of a social housing neighbourhood in Braga, Portugal. The results suggest an increase in indicators values demonstrating a negative impact on the achievable reduction of both energy and emissions when the whole life cycle approach is considered, which can constitute a critical point for policy formulation in the decarbonisation of the built environment.

Abstract The recast of the Energy Performance of Buildings Directive settle that all new buildings should reach nearly zero energy levels by 2020 (2018 for buildings owned or occupied by public authorities). Therefore, technicians involved in building design, management and approval should be able to understand and apply nearly zero energy buildings (nZEB) concepts in both new buildings and renovation of existing ones. At European Union (EU) level there are large differences in commitment to the EU targets and the construction of nZEB between countries. It is thus urgent to develop studies to demonstrate the advantages of the nZEB and ZEB design process, increasing the awareness of both building clients and other stakeholders regarding this issue. In this context, the aim of this paper is to assess the energy and environmental life cycle performance of different renovation scenarios (Basic Renovation, nZEB and ZEB) for multifamily buildings in Portugal. This will be focused on the goals of the nZEB and ZEB design process and on the contribution of solar systems (solar thermal collectors, STCs, and photovoltaic panels, PVs) in the achievement of those goals. The results presented in this paper show that, in the Portuguese climate and for a typical multifamily building, it is possible to overcome 100% of the energy needs for acclimatization and domestic hot water (DHW) preparation with the integration of solar systems. From our results, it is also possible to conclude that a significant amount of energy and carbon emissions are avoided for every renovation scenario during the considered lifetime (30 years) and that the nZEB and ZEB scenarios are cost-effective with attractive payback times.