Computer-aided architectural design and the design process

The use of computational systems in architectural science is becoming increasingly used as a research and practice methodology for a wide range of research areas. This edition presents papers which use computers to aid design, performance evaluation and fabrication. An important question is in the first two papers and concerns the use of computer simulation to assist with form finding in buildings. The last three are concernedwith the integration of the computer simulation process in the design process to achieve more effective practices. Improving productivity in design through reducing time and costs is one issue and another is font loading the design process so that performance evaluation modelling can occur at the beginning of the design process (rather than at the end), during which all the decisions havebeenmade. Thenewsystemsandprocess reported in these papers offer newopportunities in the applicationof architectural science in theory and practice. The first paper (‘Design and Fabrication with Fibre-reinforced Polymers in Architecture: A Case for Complex Geometry,’ by Arielle Blonder and Yasha J. Grobman) examines the unexplored potential of using Fibre-Reinforced Polymers (FRPs). FRP is a lightweight compositematerialwhich combines fibres andpolymers to create a strong composite material with high ratio of strength to weight and durability. The first section provides a review of the use of composites in architecture and case studies of examples. The important challenges ahead for composites are outlined for FRPs; one of which is form finding. The authors proposedand test anewdesignand fabrication system. Theyuse a digital form-finding process, which assisted with the design of the case study; however, the full benefit of structural analysis is yet to be carried out. The next paper ‘Microclimate on Building Envelopes: Testing Geometry Manipulations as an Approach for Increasing Building Envelopes’ Thermal Performance’ is by Yasha J. Grobman and Yosie Elimelech. The research examines an approach to façade design, which relies on manipulating the surface geometry to create a localized microclimate to improve the thermal performance. The authors argue . . . ‘The new approaches, inspired by envelopes in nature, will increasingly rely on geometry, alongside the traditional dependenceonmaterial, to achieve optimumbuilding performance.’ Conventional façade construction uses a series of layers of material with cavities to create the building envelope . . . ‘As opposed to the complex cellular structure of natural skins, traditional building envelopes are typically based on flat orthogonal geometry, repetition, limited functions, and structural homogeneity.’ They comment that advances in fabrication technologies as seen in the previous paper will make this feasible. The first part of the paper presents a review of the design developments of using complex façade geometries and cellular-based wall-cladding systems and the move to green walls where plants are placed in the external cavities. The next section provides a study of a range of façade geometries with external cavities. The design of these external cavities used the criteria for the thermal performance of internal cavities, that is minimize convective heat transfer by reducing flow velocities in the cavities. Next a computer fluid dynamics study was carried out to test the flow dynamics and streamlining in the different cells. The air speeds that were simulated range between 1, 5 and 10m/second. The authors report that the simulations show that airspeeds in all cavities were reduced however . . . ‘It is not clear at this stage whether this difference is significant in terms of its influence on the microclimate’s performance and its relation to the building insulation.’ Further work is needed to undertake building physical models for wind tunnel testing. ‘Moreover, having achieved a level of thermal insulation similar to that of a traditional building façade by using microclimate, it would be possible to examine and optimize the cavities of the best-performing envelope section for other functions such as natural light, selfshading, water conservation and the cultivation of vegetation (green wall).’ It is likely that the application of this research is likely to lead to solutions will be building type and climate specific. Research of this nature needs to combine computer fluid dynamics with thermal performance studies to be effective to understanding heat balance across the façade. Research by Rojas, Galán-Marín, and Fernández-Nieto (2012) into courtyard design used thermal data in conjunction with computer fluid dynamics in their simulation study to understand airflow in this type of spaces. The methodology may be of use in further research in this area. The paper by Hwang Yi on ‘User-driven Automation for Optimal Thermal-zone Layout During Space Programming Phases’ examines an approach to automating the design phase to improve energy performance and thermal comfort using simulation tools. Thermal zoning is a technique used to determine the heat loads for different orientations and functions of a building. The perimeter zone will have higher heat loads due to the climate influences on the building. Some spaces can be airconditioned and some can be naturally ventilated. In determining the airconditioning design, thermal loads and subsequent zoning are decided. The first section of the paper provides a review of thermal zoning and its relation to the functional planning of spaces. Often the location of these spaces is done based on adjacency grounds and mirrors the organizational structure of the building. The author argues that this can be done also by considerating environmental factors, whichwould be an improvement in the design process. The author suggests using a design tool that can optimize these relationships automatically. The next section presents a review of these tools and describes the development of a new tool. This is subsequently tested in the next section. Finally, the optimized design layout is tested using a thermal simulation program.