IEA EBC Annex 57 ‘Evaluation of Embodied Energy and CO_2eq for Building Construction'

The current regulations to reduce energy consumption and greenhouse gas emissions (GHG) from buildings have focused on operational energy consumption. Thus legislation excludes measurement and reduction of the embodied energy and embodied GHG emissions over the building life cycle. Embodied impacts are a significant and growing proportion and it is increasingly recognized that the focus on reducing operational energy consumption needs to be accompanied by a parallel focus on reducing embodied impacts. Over the last six years the Annex 57 has addressed this issue, with researchers from 15 countries working together to develop a detailed understanding of the multiple calculation methods and the interpretation of their results. Based on an analysis of 80 case studies, Annex 57 showed various inconsistencies in current methodological approaches, which inhibit comparisons of results and difficult development of robust reduction strategies. Reinterpreting the studies through an understanding of the methodological differences enabled the cases to be used to demonstrate a number of important strategies for the reduction of embodied impacts. Annex 57 has also produced clear recommendations for uniform definitions and templates which improve the description of system boundaries, completeness of inventory and quality of data, and consequently the transparency of embodied impact assessments

Overview and future challenges of nearly zero energy buildings (nZEB) design in Southern Europe

In times of great transition of the European construction sector to energy efficient and nearly zero energy buildings (nZEB), a market observation containing qualitative and quantitative indications should help to fill out some of the current gaps concerning the EU 2020 carbon targets. Next to the economic challenges, there are equally important factors that hinder renovating the existing residential building stock and adding newly constructed high performance buildings. Under these circumstances this paper summarises the findings of a cross-comparative study of the societal and technical barriers of nZEB implementation in 7 Southern European countries. The study analyses the present situation and provides an overview on future prospects for nZEB in Southern Europe. The result presents an overview of challenges and provides recommendations based on available empirical evidence to further lower those barriers in the European construction sector. The paper finds that the most Southern European countries are poorly prepared for nZEB implementation and especially to the challenge opportunity of retrofitting existing buildings. Creating a common approach to further develop nZEB targets, concepts and definitions in synergy with the climatic, societal and technical state of progress in Southern Europe is essential. The paper provides recommendations for actions to shift the identified gaps into opportunities for future development of climate adaptive high performance buildings. (C) 2017 Elsevier B.V. All rights reserved.info:eu-repo/semantics/publishedVersio

Outlining a new collaborative business model as a result of the green Building Information Modelling impact in the AEC supply chain

BIM (Building Information Modelling) technological push has enabled to integrate the design/construction outcomes of 3D-CAD along the product/service AEC (Architecture, Engineering and Construction) SC (supply chain) through an intelligent DMS (Data Management System) based on standard and interoperable data formats. The proposed end-to-end approach overcomes a typical AEC gap, enables the operationalisation of the sustainable/green building LCA (Life Cycle Assessment) and puts together new collaborative relationships with the owner, among SC stakeholders and with new forms of BIM procurement. The outlined collaborative business model is based on the Quality Control and Assurance framework and provides conceptual consistency to the reintroduction of the owner concerns/satisfaction in the SC, as well as enables consistent and accountable relationships between (smart)materials procurement and building specification. An expert’s focus group carried out a preliminary check of the model’s interest/applicability, resulting in recommendations for its further detailing and for propositions development into a systematic enquiring process.info:eu-repo/semantics/acceptedVersio

Sky view factor as predictor of solar availability on building façades

Solar availability on urban façades varies signifcantly, affected by obstructions by nearby buildings as well as orientation. A convenient way to evaluate their solar energy potential is deemed to facilitate the task of architects in increasing the use of photovoltaic systems and, thus solar energy generation in the urban environment. This study explores to what extent the sky view factor (SVF), a measure of the openness of a point to the sky, can be employed for evaluating solar irradiation of façades in complex urban scenes. For this purpose, extensive statistical analysis was performed testing the correlation of SVF with solar irradiances for 30 orientations, considering three European climates (i.e. Athens, London and Helsinki), and three periods (i.e. year, January and July). Special emphasis is put on global irradiance, which expresses the sum of three solar components, i.e. direct, diffuse and reflected. The study uses 24 urban forms - of 500 × 500 m area - in London for which SVF and solar irradiance simulations were performed for nine sky models (three locations by three periods). The results reveal a strong linear relationship (R2 > 0.8) between SVF and annual global irradiance in all orientations, at all three locations. In fact, as SVF was found to correlate well with both major solar components, direct and diffuse, it can be presumably used for predicting façades' annual solar irradiation at any location within the tested range of latitudes. With respect to monthly global irradiance, the relationship appears less consistent, affected by the increased sensitivity of the relationship of SVF with monthly direct irradiance to façade orientation and location's latitude, associated with the variations of solar altitude