A generative facade design method based on daylighting performance goals

Successful daylighting design is a complex task which requires the designer to consider numerous design elements and their effects on multiple performance criteria. Facades, in particular, include many variables which may dramatically impact daylighting performance. Genetic algorithms (GAs) are optimization methods which are suitable for searching large solution spaces, such as those presented by design problems. This article presents a GA-based tool which facilitates the exploration of facade designs generated based on illuminance and/or glare objectives. The method allows the user to input an original 3d massing model and performance goals. The overall building form remains the same while facade elements may change. Ten parameters are considered, including materials and geometry of apertures and shading devices. A simple building data model is used to automatically generate a 3d model of each solution. Results from single- and multi-objective case studies are presented to demonstrate a successful goal-driven design exploration process.     

Construction cost and energy performance of single family houses: From integrated design to automated optimization

The single family home market is facing increasing challenges in managing environmental issues. The required objective of building energy performance can be achieved by limiting extra cost, integrating building design, and using the most appropriate and readily available materials. However, standard computations, such as the French building energy code used here, require vocational expertise that involves managing separate processes and numerous design variables. The design is therefore restricted to well-known techniques, especially for small constructions. In this paper, the usual stakeholder constraints and possible developments in design practice are considered through the use of real product databases and vocational tools to calculate construction costs. In the first stage, which takes into account cost and energy demand, an integrated approach to building envelope design is detailed, including a semantic system to automate the process. Then an optimization method (a genetic algorithm) is proposed to assess energy performance and the cost of the building envelope. This process is illustrated as a case study for a single family house. The results highlight various optimal solution domains specific to the case study, which can be further managed through a decision support system.     

Thermo-economic optimization of rooftop unit’s evaporator coil for energy efficiency and thermal comfort

In this paper, the optimization-simulation approach is proposed to investigate energy saving potential of an air-cooled direct expansion rooftop package air conditioning system by refining the model of the HVAC system components and deriving optimal configuration for evaporator coil subject to technical constraints. In this method the frontal area of the evaporator coil is maintained as constant and the variation of other geometrical parameters on the thermal and economical performance of the system is investigated. An actual air-cooled rooftop package of a real-world commercial building in hot and dry climate conditions is used for experimental data collection. Both inputs and outputs are measured from the field monitoring in two summer weeks. Based on the mathematical models and using collected data, modules incorporating the proposed optimal redesign procedure were embedded in a transient simulation tool. A mixed heuristic- deterministic optimization algorithm was implemented in the transient tool to determine the synthesis and design variables that influence the cost and energy efficiency of each configuration. Available experimental results were compared to predicted results to validate the model. Afterwards, the computer model was used to predict how changes in cooling coil geometry would affect the building thermal comfort, the cost and energy consumption of the system.     

关于绿色建筑性能模拟优化流程的研究

建筑性能数值模拟计算分析近年来对建筑设计的影响逐渐增强,尤其当下发展日益凸出的绿色建筑,方案设计优化更离不开计算机的数值分析。而目前针对建筑性能模拟优化流程间的分析研究很少,所以在简要介绍建筑性能优化设计的概念基础上,详细分析了各建筑物理性能模拟流程间的关系,从而为建筑性能优化设计流程提供一些参考和指导。     

Computer-aided building energy analysis techniques

Buildings are slowly replacing long-term investments that consume a lot of energy. Given current economic, as well as environmental constraints on energy resources, the energy issue plays an important role in the design and operation of buildings. Careful long-term decisions in the design and operation of buildings can significantly improve their thermal performance and thus reduce their consumption of energy. Alternative building design strategies, standards compliance and economic optimization can be evaluated using available energy analysis techniques. These range from simplified manual energy analysis methods for approximate energy use estimates to detailed computerized hourly simulation. The availability and ease of use of today’s computers make them effective tools in the decision-making process of building design. This paper reviews the most common building energy analysis techniques and the potential applications of computer technology in the energy simulation and optimization of buildings.     

基于天然采光性能的建筑中庭形体设计导则研究

建筑师在进行形体创作时须将良好的技术性能作为重要目标，而直观、形象、非严格定量的设计导则是一种简易有效的辅助手段。然而，运用数字设计方法辅助建筑形体创作中的技术性能问题的既有研究对设计导则的关注较少，不能满足形体创作需求。本研究结合参数化模型、性能模拟等数字方法，以中庭为例、探讨了基于天然采光性能的圆形与方形中庭形体设计导则。研究结果表明，中庭的面积、贯穿层数、平面比例等形体参数对其天然采光性能具有显著影响，故在形体创作中建筑师应结合设计导则将天然采光性能纳入考虑；此外，本研究所采用的技术路线能够揭示建筑的技术性能与其形体特征的关系、是一种有效的设计导则获取方法。     

Seismic structural reliability using different nonlinear dynamic response surface approximations

Performance-based design in earthquake engineering should be approached as an optimization process for optimum design parameters, in order to achieve satisfactory performance over the service life. Each of the specified performance criteria should be met with a prescribed minimum reliability and, given these constraints, a minimum or optimum total cost may be sought. The reliability estimations involve a nonlinear analysis for the dynamic responses of the structure, calculated via a step by step procedure over the complete earthquake record. This task could be computationally demanding, making unfeasible the direct implementation of a standard Montecarlo simulation. Dynamic responses represented by response surfaces make the simulation and the optimization process much more efficient. This paper presents a comparison between three methods for the implementation of response surfaces: a global approximation of a deterministic database, local interpolation of that database, or using artificial neural networks. The comparison uses, as an example, a 5-story reinforced concrete building. The results show good agreement between the methods and the paper discusses their corresponding advantages and limitations.     

A multi-objective structural optimization method for serviceability design of tall buildings

Structural optimization design aims to identify optimal design variables corresponding to a minimum objective function with constraints on performance requirements. To this end, many optimization frameworks have been proposed to determine optimal structural systems that are subjected to seismic and wind hazards in isolation. However, some modern tall buildings are sensitive to seismic and wind excitation owing to their complex structural systems and geographic regions. Therefore, a proper structural optimization method for such buildings is required to ensure that the expected performance is achieved in a multi-hazard scenario. This study proposes a multi-objective serviceability design optimization methodology for buildings in multi-hazard seismic and wind environments by combining optimality criteria and the nondominated sorting genetic algorithm II (NSGA-II). Seismic and wind effects can be instantaneously updated due to changes in the structural dynamic properties during the optimal design process. A neural-network-based surrogate model with self-updating is proposed to predict the structural natural frequency so that the overall computation time of the optimization process can be reduced. The proposed method was used to optimize a 50-story frame-tube building and was compared against the general genetic algorithm and general NSGA-II to verify the feasibility and effectiveness.     

A parametric approach for performance optimization of residential building design in Beijing

During the early design stage of green residential buildings, there are tremendous potential of using parametric optimization to achieve preferable green performance, such as building energy consumption efficiency, daylighting, ventilation and thermal comfort. Taking residential design features into consideration, this paper presents an optimization workflow and effects based on a case study of a residential building project in Beijing. Firstly, 27 design parameters related to residential spatial form and building envelope were selected for the optimization. The simulation results of the cooling and heating load were taken as the optimization objects. Secondly, optimized schemes were obtained from 6246 simulation results, with 1925 verified simulation results proving that the optimized result is reliable. Finally, analysis was performed to establish the correlations between design parameters and performance in order to create the easy access for architects to determine design parameters depending on the performance sensitivity of each parameter. Analysis results showed that parametric optimization of spatial form and building envelope at the design stage is a feasible approach to reducing energy consumption in residential building design.

     

Structural dynamic optimal design based on dynamic reliability

In this work, dimension and shape optimization of structures under stochastic process excitation is addressed in the context of element or system dynamic reliability constraints, where the structural gross mass is taken to be the objective function. Firstly, based on the dynamic response analysis of truss structures under stochastic process loads, the dynamic reliability constraints are developed and simplified, and the normalization of design variables is discussed to avoid some variables being drowned by others during optimization due to their different dimensions and orders of magnitude. The optimal models of dimension and shape with element or system dynamic reliability constraints are then presented. Two numerical examples are finally used to illustrate the results of different optimal designs, which demonstrate that the efficiency to solve the structural optimization with dynamic reliability constraints can be significantly improved if the design variables and their initial values are selected properly.     

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.     

基于改进双向渐进结构优化法的桁架结构拓扑优化

为了将双向渐进结构优化法应用于桁架结构优化设计中,结合能量原理和满应力设计准则,推导了以结构最小应变能为目标函数的优化计算公式,提出了可以应用于桁架结构优化的桁架-双向渐进结构优化(T-BESO)法.T-BESO法以杆件截面面积为设计变量,以结构应变能为目标函数,以应力约束和满应力设计准则为约束条件.在T-BESO法中...     

基于ADAMS的微型装载机反转八连杆工作装置的优化设计

基于机械系统动力学软件ADAMS的仿真界面,建立装载机反转八连杆机构的虚拟样机模型,编写运动仿真脚本,最后建立设计变量及约束对反转八连杆机构进行优化设计。通过编写的仿真脚本进行优化分析,减少了优化的时间。     

BIM IFC information mapping to building energy analysis (BEA) model with manually extended material information

To reduce fossil fuel based energy consumption in buildings, different methods have been proposed. Interestingly, one of the most significant factors in building energy consumption has been reported in the area of improving building designs. However, building energy analysis (BEA) is typically conducted late in design, by energy analyst specialists. The ability to try out new ideas early in the design process in order to choose the best alternative is not ordinarily taken advantage of, due to the difficulty and expense of modeling the building and energy systems. Building information modeling (BIM) provides the user with an opportunity to explore different energy saving alternatives in the design process while avoiding the time-consuming process of re-entering all the building geometry, enclosure, and HVAC information necessary for a complete energy analysis.While significant time savings are being made by not having to create the building geometry within the simulation interface in BIM energy modeling simulation, there is a good possibility of missing, misplaced, or deformed building elements during a BIM data exchange process. This research focuses on one of the major limitations – inaccuracies through simplifications in construction/material data – and aims to improve the accuracy of energy modeling process by developing an object based approach in materials in which the energy modeler may change and expand various properties in building materials. In testing the performance of the proposed approach, the results from the proposed energy modeling process in the case study are compared to those of existing energy modeling software which showed significant gains in accuracy.     

Building energy simulation and optimization: A case study of industrial halls with varying process loads and occupancy patterns

Industrial halls are mainly low-rise rectangular-shaped structures of simple construction. The relatively loose requirements in space conditioning and the comparatively high internal heat gain make the approach in industrial hall design quite different from that of office building design. The simplicity in building geometry and construction method allows the investigation of energy consumption for building services to be limited to a few demand-side parameters, namely, resistance of the roof and wall insulation, airtightness, and amount of daylighting. This paper investigates the impact of varying these demand-side parameters on the energy consumption for space conditioning and lighting for a typical industrial hall. Through building energy simulation, such impacts can be investigated, and by applying optimization, the configurations of the most optimal combinations of demand-side parameters with the lowest energy consumption can be identified. The result suggests that there is a significant energy-saving potential. For industrial halls, energy consumption for building services can be very sensitive to changes in the process load and occupancy pattern, which in reality, fluctuate widely due to economic cycles, and other factors. Optimized design solutions for industrial halls intended for a particular process load and occupancy pattern might not perform as predicted due to potential changes. To account for potential changes, uncertainty analysis can be performed to determine if the optimized design solutions are in fact robust enough to such changes and to identify solutions that are less susceptible to uncertainty.     

建筑师主导下基于能耗模拟的建筑形体与空间组织节能设 计研究 — —以北京市门头沟区体育文化中心为例

介于当下建筑师在绿色建筑设计过 程中的长期角色缺失以及设计后期为了能耗 达标而过分依赖节能设备等现象,由建筑师 主导的、以能耗模拟为途径的节能设计研究 更加刻不容缓。在详细分析由建筑师主导的 节能设计所展现的优势并对能耗模拟工具 进行选择后,提出了建筑师主导下基于能耗 模拟的建筑形体与空间组织节能设计流程。 接下来以北京市门头沟区体育文化中心为例,展示了在方案设计阶段建筑形体与空间组织关系的节能设计思路与过程,详细剖析了建筑师对 整体概念、功能布局和能耗负荷等问题的把控与决策。最后总结了建筑本体设计与节能设计这 两者的协同关系,阐明了建筑师在其中发挥主导角色的重要意义。     

Linking BIM and Design of Experiments to balance architectural and technical design factors for energy performance

To transform the existing energy systems towards renewable energy sources, buildings need to use less energy, use energy more efficiently and harness local renewable energy sources. For the design of energy-efficient buildings, building energy simulation of varying sophistication is commonly employed. Types of simulations range from simple, static calculations to sophisticated dynamic simulation. Especially for building retrofit many assumptions on construction, material etc. have to be taken, which increases the uncertainty of simulation results. In conjunction with simulation, methods of Building Performance Optimization are increasingly employed. They are able to identify best performing designs however do not provide insights on the mechanisms and interdependencies of the different design factors, which are most valuable to make informed design decisions. We present a methodology that aims to provide a better understanding and create knowledge about the influence and interactions of different architectural and technical design factors on building energy performance of a specific design task. For this purpose, we introduce Design of Experiments (DoE) in an integrated design workflow using the Design Performance Viewer (DPV) toolset, combining Building Information Modeling (BIM), distributed dynamic simulation and statistical analysis of the extensive simulation results. The experiments created using the methodology allow to identify the strength of effects and interactions of different design factors on selected performance indicators. We apply the methodology on an office retrofit case, introducing a factor scatterplot for result visualization, development and comparison of retrofit strategies. We further evaluate its potential to identify high performing strategies while balancing architectural and technical factors and their impact on energy performance.     

Optimization of envelope and HVAC systems selection for residential buildings

In this paper, a comprehensive energy simulation environment is developed and presented to optimally select both building envelope features and heating and air conditioning system design and operation settings. The simulation environment is able to determine the building design features that minimize the life cycle costs. Three optimization algorithms are considered in the simulation environment including Genetic Algorithm, the Particle Swarm Algorithm and the Sequential Search algorithm. The robustness and the effectiveness of the three algorithms are compared to assess the performance of the simulation environment for various design applications and climatic conditions. In particular, the simulation environment has been applied to design single family homes in five US locations: Boulder, CO; Chicago, IL; Miami, FL; Phoenix, AZ; and San Francisco, CA. Optimal designs are determined to reduce life cycle costs with and without budget constraints. It is found that the optimal selection can reduce life cycle costs by 10-25% depending on the climate and type of homes.     

高层建筑地基基础概念设计的思考

基于高层建筑箱、筏、桩筏基础变形、反力等实测资料的分析指出,按传统理念设计的箱基、筏基、桩筏基础有两个缺陷:一是呈现明显的碟形沉降引起上部结构的较大次应力;二是基底马鞍形反力分布导致基础板或承台冲剪力和弯矩显著增大。为使差异沉降和箱、筏承台的内力减至最小并改善上部结构受力性状,提出变刚度调平概念设计。对于框筒、框剪结构,应强化核心筒区的桩土刚度(调整桩长、桩径或桩数),相对弱化外围刚度;对于主裙连体建筑,应强化主体,弱化裙房(采用天然地基、复合地基和疏短桩基);对于箱、筏基础,可局部强化核心筒区(采用桩基或刚性桩复合地基)。对于上述变刚度调平概念设计,进行上部结构—基础—桩—土共同作用分析,进一步优化布桩和承台配筋。通过大比例现场模型试验对上述优化设计理念进行了验证,并应用于10余项工程,取得了良好的技术经济效果。