Effort and effectiveness considerations in computational design evaluation: a case study

Computational building evaluation tools have the potential to provide an effective means to support informed design decision making. Computational modeling, however, comes with a cost. Thereby, the most important cost factor is not software acquisition, but the time needed for learning and using the software. The extent of required time and effort is believed to be one of the main hindrances toward the pervasive use of computational building performance assessment tools by designers: Currently, modeling applications are mostly used, if at all, in the later stages of design and by specialists, rather than architects. However, few studies have explicitly dealt with the ascertainment and quantification of the actual effort needed to understand, master, and apply computational building evaluation tools. Thus, little factual information is available as to the cost and burden of computational building evaluation and its effectiveness in building design support. In this context, the present paper describes a case study, whose motivation was to estimate the time and effort needed by novice designers to computationally evaluate the performance of building designs. A group of senior architecture students participated in the study, learning and using a software application to assess the energy performance of six project submissions for a school building design competition. The outcome of this study (time investment ranges for various components of the modeling activity) was evaluated and further extrapolated to estimate the effort needed for a more comprehensive computational assessment of the environmental performance of these designs.     

Integrating building information modelling with sustainability to design building projects at the conceptual stage

Lately the construction industry has become more interested in designing and constructing environmentally friendly buildings (e.g. sustainable buildings) that can provide both high performance and monetary savings. In general, sustainability integrates the following three related components: (1) environmental, (2) economic, (3) social well-being. Incorporating these components at the conceptual stage is achieved by using sustainable design, through which designers must identify associated materials and systems based on any selected certification (rating) system. The use of building information modelling (BIM) concepts helps engineers design digital models that allow owners to visualize the building before the physical implementation takes place. To apply BIM concepts, designers use tools to create 3D models of buildings where the design materials and systems are selected from the built-in database of these tools. Designers will not be able to quantify the environmental impacts of these materials to support the decisions needed to design sustainable buildings due to the following reasons: (1) a lack of information about the sustainable materials that are stored in the database, (2) a lack of interoperability between the design and analysis tools that enable full life cycle assessments (LCAs) of buildings. This paper presents a methodology that integrates BIM and LCA tools with a database for designing sustainable building projects. The methodology describes the development and implementation of a model that incorporates a database in which information about sustainable materials is stored and linked to a BIM (3D) module along with an LCA module and a certification and cost module. The goal of this model is to simplify the process of creating sustainable designs and to evaluate the environmental impacts (EI) of newly designed buildings at the conceptual stage of their life. An actual building project is presented in order to illustrate the usefulness and capabilities of the developed model.     

A comprehensive model for streamlining low-energy building design

Building designers are often limited in their ability to reduce the environmental impact of buildings, due to a lack of information on the environmental performance of building components as well as inconsistencies in the way in which this information is derived. Whilst numerous tools exist to help facilitate the low-energy building design process, these typically require large investments of time and money that are often beyond those available within any particular project. This paper describes an approach for streamlining the design process to reduce building life cycle energy consumption. Building assemblies are ranked based on an assessment of the life cycle energy requirements associated with their use within a building. This facilitates early stage assessment, negating the need for a resolved design before the relative energy requirements of alternate design solutions are known. Previous work assessed the initial and recurring embodied energy as well as the operational energy requirements for heating and cooling associated with the use of a range of building assemblies, using a simplified house model. This paper presents a sensitivity analysis of variations to the floor area, shape and orientation of this model, to test the reliability and applicability of the ranking approach across a broad range of circumstances. It was found that these variations did not influence the ranked order of the assemblies in terms of their life cycle energy requirements. Thus, the ranking of assemblies appears to provide an appropriate approach for streamlining the selection of construction elements during the building design process.     

Needs and trends in building and HVAC system design tools

Building designers are being increasingly pressurised to design buildings with high standards of energy efficiency, performance and comfort in the shortest possible time. Computer design tools have a tremendous potential for aiding designers in achieving the above design objectives. This article provides a short overview of their application in the building and HVAC field, as well as advances made in their development.The development of applications tends towards integrated and expert design tools. This is a big step towards realising optimal, energy efficient building designs. Despite these apparent advances it was found that the potential of these tools are however largely untapped. This article further identifies the reasons for this and highlights some of the aspects that need attention. The complexity of existing tools seems to be the biggest stumbling block.     

Achieving informed decision-making for net zero energy buildings design using building performance simulation tools

Building performance simulation (BPS) is the basis for informed decision-making of Net Zero Energy Buildings (NZEBs) design. This paper aims to investigate the use of building performance simulation tools as a method of informing the design decision of NZEBs. The aim of this study is to evaluate the effect of a simulation-based decision aid, ZEBO, on informed decision-making using sensitivity analysis. The objective is to assess the effect of ZEBO and other building performance simulation tools on three specific outcomes: (i) knowledge and satisfaction when using simulation for NZEB design; (ii) users’ decision-making attitudes and patterns, and (iii) performance robustness based on an energy analysis. The paper utilizes three design case studies comprising a framework to test the use of BPS tools. The paper provides results that shed light on the effectiveness of sensitivity analysis as an approach for informing the design decisions of NZEBs.     

Findings from a survey on the current use of daylight simulations in building design

This paper presents findings from a web-based survey on the current use of daylight simulations in building design. The survey was administered from December 2nd 2003 to January 19th 2004. One hundred and eighty five individuals from 27 countries completed the survey. The majority of respondents worked in Canada (20%), the United States (20%), and Germany (12%). Most participants were recruited through building simulation mailing lists. Their self-reported professions ranged from energy consultants and engineers (38%) to architects and lighting designers (31%) as well as researchers (23%). They worked predominantly on large and small offices and schools.Ninety one percent of respondents included daylighting aspects in their building design. Those who did not consider daylighting blamed lack of information and unwillingness of clients to pay for this extra service. Among those participants who were considering daylighting 79% used computer simulations. This strong sample bias towards computer simulations reflects that many participants had been recruited through building simulation mailing lists. Participants named tools’ complexity and insufficient program documentation as weaknesses of existing programs. Self-training was the most common training method for daylight simulation tools. Tool usage was significantly higher during design development than during schematic design. Most survey participants used daylighting software for parameter studies and presented the results to their clients as a basis for design decisions.While daylight factor and interior illuminances were the most commonly calculated simulation outputs, shading type and control were the most common design aspects influenced by a daylighting analysis. The use of scale model measurements had rapidly fallen compared to a 1994 survey, whereas, trust in the reliability of daylighting tools has risen. While participants named a total of 42 different daylight simulation programs that they routinely used, over 50% of program selections were for tools that use the RADIANCE simulation engine, revealing the program's predominance within the daylight simulation community.     

COMBINE: The HVAC-design prototype

Integrated intelligent building design systems (IIBDSs) are computer-based design environments which will in the future be used by engineers and architects to assist them in the design of buildings. This paper deals with the class of IIBDSs whose aim it is to improve the energy efficiency and overall performance of buildings. Development of these IIBDSs is a substantial task and may take some time to be realized. The EC COMBINE project and the U.S. AEDOT project have been initiated to take the first step towards developing these future IIBDSs. This paper focuses on the COMBINE project.

COMBINE's first step towards developing IIBDSs is to implement a building product model based on the ‘product modelling’ approach promoted by the computer-integrated manufacturing (CIM) community. This building product model allows information about a building to be passed between different design professionals (e.g. architects, heating, ventilating, and air-conditioning (HVAC) system designers etc.). Data exchange through the product model is tested using various design prototypes one of which is called the HVAC-Design prototype. The HVAC-Design prototype helps a HVAC system designer to select a preliminary HVAC system for a building.

This paper reviews: (a) ongoing research into the development of IIBDSs and (b) various software tools which may be incorporated into future IIBDSs. The main emphasis of the paper is on the COMBINE project and the functionality of the HVAC-Design prototype in COMBINE. There is also a discussion on how HVAC-Design may develop in the future.     

Shared conceptual model for the building envelope design process

The lack of communication and co-ordination among designers during the building envelope design process results in sub-optimal solutions leading to inadequate performance. To reverse this trend and to achieve better performance of the building envelope, professionals must be provided with computer integrated design tools which facilitate communication between participants and improve the transfer of data throughout the design process. This article presents a shared conceptual model that would enable integration in the building envelope design process. The wealth of data is organized into major envelope entities which are then decomposed into cohesive sets of data called primitives to form the conceptual model. Such a conceptual model should facilitate data exchange between design tasks, improve communications among designers and support the growth of data as the design process unfolds. The resulting conceptual model is implemented as a shared central database in an object-oriented database management system to experiment with integration.     

The problem of durability in building design

Durability is an integral part of modern building design. The demands for innovative building techniques and the inclusion of materials and components with lower life-cycle costs test the knowledge and skills of building designers. The pressing need for reliable information about the role of durability in the building design process has led to the formation of a working commission on ‘Design for Durability’ (CIB W94) by the international Council for Building Research, Studies and Documentation (CIB). This paper is a state-of-the-art review of this area based largely on the proceedings of the International Conferences on the Durability of Building Materials and Components held in 1978, 1981, 1984, 1987 and 1990. The paper emphasizes the importance of the development and utilization of an internationally accepted systematic approach to the durability problem in building design, and of the development of computerized expert systems to support designers with decision making information.     

Creating flexible mappings between Building Information Models and cost information

During the early design stages of construction projects, accurate and timely cost feedback is critical to design decision making. This is particularly challenging for cost estimators, as they must quickly and accurately estimate the cost of the building when the design is still incomplete and evolving. State-of-the-art software tools typically use a rule-based approach to generate detailed quantities from the design details present in a building model and relate them to the cost items in a cost estimating database. In this paper, we propose a generic approach for creating and maintaining a cost estimate using flexible mappings between a building model and a cost estimate. The approach uses queries on the building design that are used to populate views, and each view is then associated with one or more cost items. The benefit of this approach is that the flexibility of modern query languages allows the estimator to encode a broad variety of relationships between the design and estimate. It also avoids the use of a common standard to which both designers and estimators must conform, allowing the estimator added flexibility and functionality to their work.     

Introducing the qualitative performance gap: stories about a sustainable building

ABSTRACT

In the design and operations industries, the performance gap is a common discrepancy found between predicted building energy performance and actual energy performance. The performance gap is considered to have negative impacts for the brand of ‘green’ buildings, designers and operators. A socially based analogue is proposed here: the qualitative performance gap, defined as the perceived gap between what inhabitants expect and their actual experience of the building environment. This concept is explored at a regenerative Living Lab: the Centre for Interactive Research on Sustainability (CIRS) in Vancouver, Canada. ‘Official’ and ‘lived’ stories about the building were interpreted from sources of building information and interviews. Expectations about and forgiveness of building performance were gained from pre- and post-occupancy evaluations and interviews. The solution to the qualitative performance gap is not to eliminate it, but, in line with the concept of interactive adaptivity, to use the gap to generate new stories and new consequences for human wellbeing. The qualitative performance gap is thus conceived as positively generative, of new stories of place and identity. This work recommends crafting an ‘official story’ of social aspirations, and a communication feedback loop amongst designers, operators and building inhabitants, transparently sharing successes and failures.     

Integration of fire safety and building design

A new framework is presented to facilitate better incorporation of building fire safety performance options into the building design process. Based on the building design process and key design decisions undertaken at each phase, a knowledge set is developed to aid building designers to understand better the effects of design decisions on building fire performance. This also minimizes potential competing objectives in later design phases by sharing necessary concerns in advance. Drawing on the knowledge set, a conceptual building fire safety evaluation tool illustrates how primary building designers and fire safety engineers can quantitatively assess fire safety performance for different solutions. It is shown how building fire safety performance attributes can be arranged by building design phase, how various scenarios can be explored, and how appropriately balanced building design and fire safety design solutions can be identified at different phases of the building design process.     

BIM技术在三亚新海干部疗养基地设计中的应用(连载二)

传统的2D CAD技术在对建筑进行描述的过程中,由于建筑的平面和立面以及详图都是分开设计,不仅仅耗费时间,而且常常出现错误,难以将建筑形态加以详细准确描述,同时,由于CAD本身的局限性,设计师很难对二维空间模型做出准确的建筑性能分析。BIM技术的出现使设计师从二维平面拓展到三维空间,并且通过信息模型能准确的进行建筑性能分析。本文以三亚新海干部疗养基地为例,阐述了BIM技术在该项目设计过程中的应用,同时重点研究BIM技术和其他建筑性能分析软件的协同对接过程,归纳了一系列对可持续建筑设计具有指导意义的设计流程。     

Assessment of natural and hybrid ventilation models in whole-building energy simulations

Natural ventilation is a traditional cost-effective technique to cool and ventilate buildings. Proper simulation tools are highly desired to ensure acceptable thermal performance of naturally ventilated buildings and to assist the design and optimization of such buildings. This study is to advance the use of natural and hybrid ventilation concepts in building design by assessing the accuracy and usability of current thermal-ventilation models. Because of the similarity noted among various models and tools, a prevalent airflow-thermal modeling program, EnergyPlus, was evaluated by simulating three selected real buildings that were supplied with most detailed building and measurement information. The study of these cases reveals that the current model has (1) significant functional limitations for venting and exhaust fan control schemes; (2) need for additional relationships to describe horizontal openings and fully-open connections between zones; and (3) possible over-prediction of buoyancy-driven flows in the case of multi-story buildings. The study further indicates the building and measurement data that are critical for a more accurate validation of thermal-ventilation models, including, on-site measured temperature, wind, and solar conditions; measured volume flow rate data, at critical points throughout the building; and effective area and discharge coefficients for specific vents used in building.     

A multi-objective feedback approach for evaluating sequential conceptual building design decisions

Conceptual design decision-making plays a critical role in determining life-cycle environmental impact and cost performance of buildings. Stakeholders often make these decisions without a quantitative understanding of how a particular decision will impact future choices or a project's ultimate performance. The proposed sequential decision support methodology provides stakeholders with quantitative information on the relative influence conceptual design stage decisions have on a project's life-cycle environmental impact and life-cycle cost. A case study is presented showing how the proposed methodology may be used by designers considering these performance criteria. Sensitivity analysis is performed on thousands of computationally generated building alternatives. Results are presented in the form of probabilistic distributions showing the degree to which each decision helps in achieving a given performance criterion. The method provides environmental impact and cost feedback throughout the sequential building design process, thereby guiding designers in creating low-carbon, low-cost buildings at the conceptual design phase.     

Technology adoption: breaking down barriers using a virtual reality design support tool for hybrid concrete

The use of hybrid concrete technologies as a viable solution to traditional frame design has been inhibited by a general lack of information. The uptake of this technology has therefore been slow and parochial, as designers have tended to stay loyal to ‘traditional’, tried and tested technologies—their ‘comfort zone’. This research identifies the barriers associated with technology adoption at industry, organization and individual levels; and uses hybrid concrete as the core context for discussion. The role of an enabling design support tool (HyCon) is presented, which can allow designers to overcome these inhibitors by providing an immersive, interactive and information‐rich environment through which design solutions can be explored. This collaborative research project describes a ‘proof of concept’ design support tool to promote the use of hybrid concrete in structural frames. It encompasses knowledge creation, application and sharing functionality, to envision support and use of this new technology—thereby promoting organizational learning. Research findings note that, while design tools have a valuable role to play, it is also important to appreciate that the uptake of any new technology is a social phenomenon, and that subsequent adoption/uptake requires careful embedding and augmentation into company organizational systems in order to leverage advantage.     

建筑防火性能化设计中火灾场景的设定

性能化防火设计方法的应用为我国建筑防火设计领域中的有关难题提供了较为科学合理的解决方案，同时也对设计者提出了更高的要求。设计者对设计过程、方法以及工具有一个比较深入全面地认识，是保证建筑防火设计安全合理的基本前提之一。通过对建筑防火性能化设计的火灾场景问题进行探讨，以求科学地认识和理解性能化防火设计方法，促进性能化防火设计方法在在我国建筑防火设计领域的健康发展。     

Method and simulation program informed decisions in the early stages of building design

The early stages of building design include a number of decisions which have a strong influence on the performance of the building throughout the rest of the process. It is therefore important that designers are aware of the consequences of these design decisions. This paper presents a method for making informed decisions in the early stages of building design to fulfil performance requirements with regard to energy consumption and indoor environment. The method is operationalised in a program that utilises a simple simulation program to make performance predictions of user-defined parameter variations. The program then presents the output in a way that enables designers to make informed decisions. The method and the program reduce the need for design iterations, reducing time consumption and construction costs, to obtain the intended energy performance and indoor environment.     

Building information model based energy/exergy performance assessment in early design stages

Due to the rising awareness of climate change and resulting building regulations worldwide, building designers increasingly have to consider the energy performance of their building designs. Currently, performance simulation is mostly executed after the design stage and thus not integrated into design decision-making. In order to evaluate the dependencies of performance criteria on form, material and technical systems, building performance assessment has to be seamlessly integrated into the design process. In this approach, the capability of building information models to store multi-disciplinary information is utilized to access parameters necessary for performance calculations. In addition to the calculation of energy balances, the concept of exergy is used to evaluate the quality of energy sources, resulting in a higher flexibility of measures to optimize a building design. A prototypical tool integrated into a building information modelling software is described, enabling instantaneous energy and exergy calculations and the graphical visualisation of the resulting performance indices.     

A framework to integrate object-oriented physical modelling with building information modelling for building thermal simulation

This paper presents a framework for integrating building information modelling (BIM) and object-oriented physical modelling-based building energy modelling (BEM) focusing on thermal simulation to support decision-making in the design process. The framework is made of a system interface between BIM and Modelica-based BEM and the visualization of simulation results for building designers. The interface consists of the following two major features: (1) pre-processing BIM models to add required thermal parameters into BIM and generate the building topology and (2) translating BIM to Modelica-based building energy modelling automatically and running the thermal simulation. The visualization component presents the simulation results in BIM for designers to understand the relationship between design decisions and the building performance. For the framework implementation, we have created a ModelicaBIM library and utilized the Modelica Buildings library developed by the Lawrence Berkeley National Laboratory. We conducted a case study to demonstrate and validate the framework simulation results.