On supporting design decisions in conceptual design addressing specification uncertainties using performance simulation

Building performance simulation (BPS) is a powerful technique to predict the performance of a design proposal. It is extensively used towards the end of the design process to, for example, prove code compliance. However, its potential to provide design guidance early in the design process is rarely exploited. That is although decisions taken during conceptual design have a disproportionate impact on the final building performance, relative to time and effort consumed (Domeschek et al, 1994). To intensify the use of BPS early is to extend its capabilities. One issue to be addressed is the building performance uncertainty due to a wide range of plausible (uncertain) design decisions. A case study was conducted to evaluate the use and potential of uncertainty and sensitivity analysis techniques in BPS to support conceptual design. It was found that the techniques can be implemented with little effort. The results are promising for making explicit design decisions and for improving inter-design team communication

Scenario analysis for the robustness assessment of building design alternatives : a Dutch case study

This paper discusses the use of exploratory scenarios with environmental conditions on a case study in the Dutch context. The goal is thereby to assess the robustness of design alternatives during the lifetime of its building components. During building design it is common practice to use "normative" scenarios to prove compliance with design standards. The use of "exploratory" scenarios is less common. However, it is hypothized that the use of exploratory scenarios is a meaningful alternative, if no information is available on the uncertainty of input data such as climate and building use. This paper focusses particularly on the performance variability due to climate change. The European Commission targets a 20% reduction of CO2 emissions, a 20% increase of energy efficiency and a 20% increase in the use of renewable energy by 2020 still providing comfortable conditions within the buildings. As neither, building use nor environmental conditions are constants, it is necessary to quantify their influence on the energy use over the lifetime of its building components and subsequently on achieving the overall aim. For the designer it is impossible to assess the contribution of his/her individual building project on achieving the goals posed by the European Commission. However, considering the performance of the building and its components under potential future conditions, conditions deviating from the design conditions, has the potential to support design by supporting the selection of design alternatives, provide comfortable conditions and reduce energy demand during building operation. To integrate building use and environmental conditions into the computational performance assessment, their stochastic character needs to be taken into account, which is rarely possible due to limited availability of data. Still, in the absence of stochastic input data the use of exploratory scenarios represents a feasible alternative to map the variability of building use and environmental conditions. The paper concludes that exploratory scenarios present a feasible alternative to assess the future performance of potential design alternatives. Its application on the case study allows to identify the most robust out of three design alternatives by considering the performance indicators energy use and thermal comfort

Uncertainty analysis for conceptual building design - a review of input data

State of the art building performance simulation tools lack capabilities to support practitioners during the conceptual building design stage. [Hopfe et al, 2005] It is hypothesized that risk assessment techniques dedicated to the analysis of uncertainties and sensitivities have the potential to provide a basis for objective decisions during the early design stages. Concentrating on material properties, the paper presents preliminary results from a literature survey dedicated to locating appropriate input data for conducting risk assessments. Of specific interest are hereby the reliability of the source data as well as the method to obtain the mean value and standard deviation

Usability evaluation of a prototype design tool for uncertainty propagation and sensitivity analysis

Software developments in the domain of building performance simulation (BPS) targeting the early design stages of a building need to address two points successfully to be adopted in design practice: (1) facilitating communication between multiple engineering disciplines and (2) the limited amount of design information. The authors consider the limited amount of design information available not as a limit but as a design uncertainty. To focus the designer’s attention the approach chosen here is to extend the capabilities of existing simulation tools with uncertainty and sensitivity analysis. The development of software goes as any product development through stages as design, synthesis and analysis and involves numerous design iterations. The analysis of the prototypical tool extension includes verification und usability evaluation. Whilst the verification of prototypical design tools is necessary to ensure the added analysis functionality is implemented correctly the usability evaluation is to ensure the proposed feature meets the demand of the potential user group. A heuristic usability evaluation was conducted with six expert practitioners using a paper prototype. The quantitative feedback to heuristics as design guidance, process integration, and application confirmed the potential of the tool extension to support design practice. The usability evaluation indicated that expert practitioners would encourage the use of uncertainty propagation and sensitivity analysis if tool extensions to BPS-tools were available. The experts assess uncertainty propagation and sensitivity analysis to add value by reducing the risk of technical design decisions and limiting the extent of design iterations

Design optimization during the different design stages

The A/E/C (Architecture, Engineering, Construction) industry is very traditional. In contrast to other industries (e.g. car or ship industry) no prototypes are trialled and tested before manufacturing. Each building is unique, thereby excluding large scale production. Over the past thirty years, computers have become ubiquitous even in the AEC industry. Yet in building design we are still exchanging data and making design decisions as a century ago, with paper drawings and reports. Although building design support tools are used for design confirmation at the end of the design process, important decisions are already made in the conceptual design stage. This paper reports an ongoing research which focuses on the different stages of the design process, their needs and key issues. Depending on the distinction of the design stages, literature review was done in the field of Multi-objective evolutionary algorithms. The variability in the definition of their fitnessfunction, the difference of inheritance, mutation etc. could add benefit to one specific design stage. The paper finishes with indicating trends for future work

On incorporating uncertainty analysis in abstract building performance simulation tools

Building Performance Simulation (BPS) is a powerful measure to educate the building design process. However, its use in practice is too large extends limited to the detailed design stage dedicated to the code compliance analysis of worked out design proposals. BPS is not much used to support the conceptual design stage (CDS). To date BPS – tools are regarded as pure analysis tools, which do not provide design information. It is hypothesized that, when integrating uncertainty analysis techniques to existing BPS – tools (incremental research approach) valuable design information can be provided. The paper gives an update on the process to integrate an uncertainty assessment capability to a tool specifically developed to support the conceptual design stage. The resulting prototype should be capable of providing information about the deviation of specific design parameters (simulation output) based on the uncertainties of the building concept specification (simulation input). In addition to the total uncertainties, the results also indicate sensitivities of the design parameters as a result of the concept specification variation. This paper describes an approach to add extra-capabilities to legacy simulation tools and presents a comparison of uncertainties and total sensitivities calculated with one detailed design analysis (DDA) tool, IES, and one conceptual design analysis (CDA) tool , LEA. The main focus was herby the representation of material properties and its impact on the model uncertainty

On incorporating uncertainty analysis in abstract building performance simulation tools

Building Performance Simulation (BPS) is a powerful measure to educate the building design process. However, its use in practice is too large extends limited to the detailed design stage dedicated to the code compliance analysis of worked out design proposals. BPS is not much used to support the conceptual design stage (CDS). To date BPS – tools are regarded as pure analysis tools, which do not provide design information. It is hypothesized that, when integrating uncertainty analysis techniques to existing BPS – tools (incremental research approach) valuable design information can be provided. The paper gives an update on the process to integrate an uncertainty assessment capability to a tool specifically developed to support the conceptual design stage. The resulting prototype should be capable of providing information about the deviation of specific design parameters (simulation output) based on the uncertainties of the building concept specification (simulation input). In addition to the total uncertainties, the results also indicate sensitivities of the design parameters as a result of the concept specification variation. This paper describes an approach to add extra-capabilities to legacy simulation tools and presents a comparison of uncertainties and total sensitivities calculated with one detailed design analysis (DDA) tool, IES, and one conceptual design analysis (CDA) tool , LEA. The main focus was herby the representation of material properties and its impact on the model uncertainty

Impact of Fluid circulation in old oceanic Lithosphere on the seismicity of transfOrm-type plate boundaries: The FLOWS project (EU-COST ES1301)

Nuzzo, Marianne ... et. al.-- European Geosciences Union General Assembly 2014 (EGU2014), 27 april - 2 may 2014, Vienna, Austria.-- 1 pageThe recent occurrence of large earthquakes and the discovery of deep fluid seepage calls for a revision of the postulated hydrogeological inactivity and low seismic activity of old oceanic transform-type plate boundaries. Both processes are intrinsically associated. The COST Action FLOWS seeks to merge the expertise of a large number of research groups and supports the development of multidisciplinary knowledge on how seep fluid (bio)chemistry relates to seismicity. It aims to identify (bio)geochemical proxies for the detection of precursory seismic signals and to develop innovative physico-chemical sensors for deep-ocean seismogenic faults. At present, study areas include the Azores-Gibraltar Fracture Zone and the North Anatolian Fault which have generated some of the most devastating earthquakes in Europe. Here we present the latest results from recently-discovered deep-sea mud volcanoes (MVs) located at the rim of the Horseshoe Abyssal Plain, western Gulf of Cadiz (NE Atlantic Ocean). An analysis of the molecular and isotopic composition of hydrocarbon and noble gases is performed on fluids collected at the newly-discovered seeps and in MVs located across the active sedimentary wedge of the Gulf of Cadiz. The tectonic and seismic environments involved vary. However, all active seeps are located along crustal strike-slip faults, which clearly control the seepage of the deep-sourced fluids. Our results yield insights into the effects of the interplay of petroleum migration/trapping, deep sediment dewatering and gas hydrate formation on the geochemical signature of natural gas in deep marine sediments. The cross-disciplinary approach fostered by the FLOWS project yields first indications on the relations between tectonics and seismicity and the secondary processes that shape the geochemical compositions of the fluids transported from deeply buried sediments to the seafloor. It highlights the role of strike-slip faults as the locus of deep fluid transport to the surfacePeer Reviewe