Exergy-based Index for the assessment of building sustainability

• Main Author: El shenawy, Ahmed
• Format: Others
• Published: 2013
• Online Access: http://spectrum.library.concordia.ca/977298/4/El_shenawy_PhD_F2013.pdf; El shenawy, Ahmed <http://spectrum.library.concordia.ca/view/creators/El_shenawy=3AAhmed=3A=3A.html> (2013) Exergy-based Index for the assessment of building sustainability. PhD thesis, Concordia University.

ABSTRACT Exergy-based Index for the assessment of building sustainability Ahmed El shenawy, Ph.D. Concordia University, 2013 The declining state of the environment, combined with the increasing scarcity of natural resources and economic recession, presents us with the need to discover building practices that are capable of producing sustainable buildings. Building promoters are racing to certify the sustainability of their projects, aware that building sustainability assessment will delineate the features of current and future building practice. A sustainable building implies that resource depletion and waste emissions are considered during its whole life cycle. This research project proposes a new methodology and Exergy-based Index to assess building sustainability and to assist decision makers comparing building alternatives, since the wrong decisions can lead to serious consequences and even precipitate crises. The proposed methodology uses the SBTool that has been utilized for defining the criteria for analysing and ranking the environmental performance of buildings. Over the past decade, significant efforts have been made in developing Sustainable Building (SB) assessment tools that allow all stakeholders/actors to be aware of the consequences of various choices and to assess building performance. These SB tools, approaches, rating systems, indices and methods of assessment have already been utilized in the market (e.g., Multi-Criteria Assessment (MCA) methods, such as LEED and SBTool, Life Cycle Analysis (LCA) systems, like ATHENA, and the Single Index (SI) approach (Ecological footprint)). However, are existing SB assessment tools actually capable of considering the regional issues? Is it possible to use them to assess all types of buildings? Are they objective, easy to customize? Is it easy to interpret their final assessment results and are those results transparent to the end users? Despite the usefulness of the current assessment methods in contributing towards a more sustainable building industry, some of the limitations and critiques of these assessment methods indicate that the tools should evolve toward a genuinely generic and scientifically global SB assessment tool. After discussing and summarizing the limitations of the existing definitions, indices and rating systems for building sustainability assessment, a definition of a sustainable building in terms of thermodynamics is proposed, mainly based on the exergy concept. This proposal is supported by a general mathematical calculation for the exergy-based index of building sustainability. The index uses the comparison between the available solar exergy (considered to be the only renewable energy source) and the exergy lost due to a building’s construction and operation to measure the a building’s sustainability. Moreover, the selection and transfer of data from the SBTool, and the assumptions and additional calculations required for the assessment of the exergy-based index of sustainability are presented and quantified. A rating scale is also presented along with the index of building sustainability. Finally, case studies of residential and commercial buildings are used to demonstrate the framework’s reliability. The contribution of the proposed Exergy-based index is evaluated by comparing its similarities and differences with a selection of the available building assessment tools and methods.