Human centred performance approach (hcpa) for adaptive facade design

Abstract

Adaptive facade systems are one of the significant developments in the facade industry over the last decades, which could be defined as multifunctional elements that are able to change their functions, features or behaviours, in response to changing external conditions and/or performance requirements. With their changeability, in principle, adaptive facade systems are offering an intelligent design notion to improve the energy performance of the building by means of optimization between the user comfort and energy consumption. However, when the performance of the facade is considered from the building occupants' perspective, the interactions between the facade and the user may not always result in a positive user experience. In order to bridge this performance gap, this doctoral study is proposing a change of perspective in facade design to a human-centred one. An expert mindset is embraced for the human-centred design approach and focuses on designing for the user over the questions: what do users want from their facade and to what extent do the adaptive technologies have the potential to fulfil their needs? It could be said that, towards reaching the full potential of the adaptive facades, there is a lack of information flow from the occupant (user) to the designer (architect). The scatteredness of information on adaptive facade technologies in the literature caused by the rapid technological developments confines the availability of knowledge for those outside the facade sector. In that respect, especially in a traditional architectural design process, it is becoming challenging for the architects to make early design decisions considering different functions of the facade simultaneously; like providing a comfortable indoor climate, energy efficiency, aesthetics, reasonable construction, easy maintenance and durability. In this complex decision-making process, holistic design support models are in need, promoting different ways of design thinking and adapting to different requirements of projects. Besides, by implementing a human-centred approach starting from the early stages of design, it would be possible to reach more user-oriented, energy-efficient and feasible design solutions, while enriching the architectural identity. In that respect, the doctoral study is focusing on the users' perspective and presents a human-centred performance approach to adaptive facade design. The study aims to aid architects' decision-making in the early design stage, by providing comparative information on the adaptive facade technologies in terms of their human-centred performance. The general flow of the research consists of two parts; (1) building the theoretical framework, and (2) developing the human-centred performance approach. In the first part, the results of the literature review process and derived considerations are presented. The context of the systematic overview could be listed as; architectural design and facade design process, decision-making methods, adaptive facades definition, classification, build examples and technologies, human-centred design approaches, user experience concept, and factors affecting the user-facade relationship. Within the scope of the research, adaptive facade technologies were categorized into 5 groups; T01 - Movable Shading Elements (Outside), T02 - Ventilated Double Skin Facades, T03 - Thermally Activated System, T04 - Movable Shell / Structure, and T05 - Smart Material / Component. Since smart materials and components refers to an adaptation at different level (micro) than the rest of the technology groups (macro), T05 group is left out of the scope during the development of human centred performance approach. In addition, the user experience concept was defined over the human senses (seeing, feeling, hearing and controlling), including the expectations and preferences of the user through their passive (direct effect) or active (indirect effect) interactions with the facade. In the second part, building on the theoretical framework, a human-centred performance approach has been developed over three main stages: (1) understanding users, (2) understanding technologies, and (3) designing for the users. Firstly, novel human-centred performance criteria were determined based on the results of the conducted user experience survey. Outcomes of this study also present the difference in preference levels of defined user experiences with facades in work environments, for different user groups according to human (age, gender, country of origin, education level, profession) and environmental (location, etc.) factors. Secondly, the expert opinion survey method was used to validate the defined criteria and performance evaluations of adaptive facade technology groups were made defining their potentials and barriers. Comparative representation of the information on technologies provides a medium for evaluation, offering data for both qualitative (stimulates visual thinking) and quantitative (numerical data for multi-criteria decision-making tools) methods of decision-making. Lastly, a model is proposed for the use of the human-centred performance approach in the (adaptive) facade design process and a flexible roadmap demonstrating its application is presented. The proposed model consists of 3 steps in line with the early stages of the facade design; (1) identifying user requirements as part of strategic planning – referring to the HCPC, (2) researching adaptive facade technologies during research and preparation – referring to the evaluations on the performance potentials and barriers of technology groups, and (3) researching application alternatives for technology groups during the concept design phases – referring to the rank order for alternative applications based on criteria groups. Considering the needs of different scenarios and different ways of design thinking, alternative pathways that can be followed in the model were described. All in all, by defining how each piece of information that is presented in the thesis manuscript could be used, the outcomes of the doctoral study are targeted to be used as a reference book that aids the architect's decision-making in the early stages of facade design.