Sound-absorbing barriers and screens are commonly employed to mitigate one of the most annoying noises in workplaces: intelligible speech. However, isolating their acoustic contribution from all the other elements (ceilings, wall treatment, or carpets) is challenging. This study uses a wave-based room acoustic modeling approach to explore the acoustic function of desk screens in a virtually reconstructed open-plan office. Analytical models, finite-element simulations, and experimental data from 3D-printed samples allowed defining a multi-resonator unit cell, attenuating the voice signal's main formants. The sound-absorbing panels composed of the unit modules iteration are assessed in the full-scale digital model, starting from the calibrated version on in-field measurements. The wave-based engine employed in this study grants the crucial aspect of computing the acoustic performance of the potential multi-resonator screens, including the edge diffraction due to their desk installation. In the virtual workplace, the acoustic role of such screens in increasing the speech level decay is outlined in comparison with the calibrated scenario and the traditional screens' option.@en

Optimizing the layout of residential buildings based on daylight performance and view quality is crucial to visual comfort and well-being of building occupants. Machine Learning (ML) methods offer valuable support for performance-based decision-making process at the early-stage building design. In this study, a novel workflow is introduced to integrate ML models into the architectural design process. With the designer’s input floor layout designs, the presented multimodal ML model predicts daylight provision and view quality, which are then translated into practical visual representations by a post-processing step. This approach allows input designs to be evaluated by the ML model, leading to enhanced design decisions while preserving the designer’s autonomy. Results for the best-performing model, implementing ResNet50 and a fully connected network, led to a Mean Square Error (MSE) of 0.0440 and 0.0478, and an R2 score of 0.7411 and 0.7815 for the daylight and view metrics, respectively. The results of the daylight and view predictive models are further interpreted according to different apartment categories and at various resolutions. These results indicate that the method could be viable for predicting daylight provision and view quality in early design tools, providing designers with faster feedback that supports informed decision-making during design iterations. Ultimately, the challenges of the study and further improvements are discussed.@en

Under urgent sustainability targets, the building industry craves for renewable and recyclable biomaterials as cellulose is a fiber; Lignin is a plant-derived low-cost polymer with remarkable properties, yet its valorization is in its infancy. Recent studies have shown potentials to combine cellulose and lignin into a renewable bio-based material for the built environment, with the use of additive manufacturing to allow geometric customization and local control of material. However, previous studies also highlighted crucial issues to be solved. One main challenge is the lack of knowledge on combinations of lignin and cellulose with different binders to achieve a paste suitable for 3D printing, leading to a material applicable in the built environment. To contribute overcoming the challenge, this research aimed to explore various combinations of cellulose, lignin, and binders and to study the extrudability of the resulting paste using a clay extruder installed on a robotic arm. Several combinations were explored, evaluated, and compared. The four recipes with the highest scores were used to produce samples for tensile and three-point bending tests, water absorption and retention tests, and microscope analysis. The overall outcome has shown similarities between the mechanical properties of the mixture developed using methylcellulose as the binding agent and rigid polymer foams, such as the ones commonly used as insulation panels. Moreover, the material mix with the highest score in the preliminary assessment was further applied to fabricate samples with varied geometries to assess its potential and limitations combined with the fabrication process. Finally, two demonstrators were produced to explore the printing process for different geometric configurations: conceptual window frame and structural node were designed, and 3D printed as proof of concept.@en

This study proposes a novel method of solar geometry by considering the potential application of point cloud data combined with the simulation of solar radiation. With the support of geometric and radiometric information stored in the point cloud such as position information (XYZ) color information (RGB), and reflection intensity (I), architects may compensate for missing information on the existing context during the simulation, especially due to the limited capacity of current 3D modelling sites. However, the dataset often comes in the format of unstructured point cloud data retrieved from merged data scans and as a result, the radiometric information is difficult to occupy due to multiple reference points. Through a 3D subtractive procedure, this study not only examines volumetric samples of the three-dimensional matrix that fulfills the criteria of solar envelopes but also finds the optimal values of the merged data scan for input of solar radiation. In this regard, simulation of solar radiation contributes to identifying the most and the least exposed areas to the sun in existing contexts. This provides information related to visible sun hours that can be used to perform ray tracing analysis between the proposed 3D plot and surrounding contexts. Our proposed method ultimately helps architects not only generate solar geometry based on real contextual settings but also to understand comprehensively the microclimate conditions of the design context.

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CAAD Futures is a biennial international conference on Computer-Aided Architectural Design under the umbrella of the CAAD Futures Foundation, and it is active world-wide in advancing and documenting related research. On 5–7 July 2023, the 20th CAAD Futures conference was hosted at Delft University of Technology. The CAAD Futures Foundation was established in 1985, holding the first conference on 18–19 September of that year at the very same University. The return of the conference to Delft for its 20thedition offered a chance to reflect on the past, present and future role of Computation in Architecture and the Built Environment. With reference to the theme of “INTERCONNECTIONS: Co-computing beyond boundaries”, CAAD Futures 2023 reflected on the role of computation to interconnect in and for Architectural Design.@en

This paper discusses a novel, compact sound absorption solution with high performance at various frequencies, including low frequencies, achieved through the effective use of Computational Design and Additive Manufacturing (AM). Sound absorption is widely applied for reducing noise and improving room acoustics; however, it is often constrained by conventional design, material properties and production techniques, which offer limited options for customising performance. This research highlights that AM, in combination with computational design tools, can support the development of novel sound-absorbing products with high performance based on the principle of viscothermal wave propagation in prismatic tubes. The potential of these designs was explored via two studies of customised sound-absorbing panels whose performance was measured in a reverberation room. A custom measurement technique was used based on logarithmic sweeps with high-resolution FFT analysis. A comparison of the measurement results with the theory of viscothermal wave propagation indicated good agreement; thus, this study demonstrates the possibility of developing new concepts and design methods for novel room acoustic devices.@en

Myopia is on the rise worldwide and its onset can be triggered by environmental factors, including light exposure. Guaranteeing an adequate exposure to daylight is particularly important for young children, whose eyes need the best conditions for a healthy development. Monitoring and assessing light levels in school buildings is therefore paramount for studies on myopia but it can prove challenging. This paper paves the way for the use of climate-based daylight simulation as a tool to complement field studies on myopia. Existing simulation tools were found to characterise vertical spot illuminance with an acceptable error range (rMBE=8,7%; rMAE=35,4%), as well as cumulative daily illuminance (rMBE=-10%; rMAE=12,6%). Spectral simulation resulted instead in larger errors, mostly for wavelengths at the edges of the visible range, previously found to be important factors in the onset of myopia. Despite current limitations, simulation tools could become an essential support for future research on myopia.@en

As technology advances, architects often employ innovative, non-standard shapes in their designs for the fast-growing number of high-rise buildings. Conversely, climate change is bringing about an increasing number of dangerous wind events causing damage to buildings and their surroundings. These factors further complicate the already difficult field of structural wind analysis. Current methods for calculating structural wind response, such as the Eurocode, do not provide methods for unconventional building shapes or, in the case of physical wind tunnel test and in-depth computational fluid dynamics (CFD) simulation, they are prohibitively expensive and time-consuming. Thus, wind load analysis is often relegated to late in the design process. This paper presents the development of a computational method to analyze the effect of wind on the structural behavior of a 3D building model and optimize the external geometry to reduce those effects at an early design phase. It combines CFD, finite-element analysis (FEA), and an optimization algorithm in the popular parametric design tool, Grasshopper. This allows it to be used in an early design stage for performance-based design exploration in complement to the more traditional late-stage methods outlined above. After developing the method and testing the timeliness and precision of the CFD, and FEA portions on case study buildings, the tool was able to output an optimal geometry as well as a database of improved geometric options with their corresponding performance for the wind loading.

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Up to now, fabricating cast glass components of substantial mass and/or thickness involves a lengthy and perplex annealing process. This has limited the use of this glass manufacturing method in the built environment to simple objects up to the size of regular building bricks, which can be annealed within a few hours. For the first time, structural topological optimization (TO) is investigated as an approach to design monolithic loadbearing cast-glass elements of substantial mass and dimensions, with significantly reduced annealing times. The research is two-fold. First, a numerical exploration is performed. The potential of reducing mass while maintaining satisfactory stiffness of a structural component is done through a case-study, in which a cast-glass grid shell node is designed and optimised. To achieve this, several design criteria in respect to glass as a material, casting as the manufacturing process and TO as a design method, are formulated and applied in the optimisation. It is concluded that a TO approach fully suited for three-dimensional glass design is as of yet not available. For this research, strain- or compliance based TO is selected for the optimization of the three-dimensional, cast glass grid shell node; in our case, we consider that a strain based TO allows for a better exploration of the thickness reduction, which, in turn, has a major influence on the annealing time of cast glass. In comparison, in a stress-based optimization, the considerably lower tensile strength of glass would become the main restrain, leaving underutilized the higher compressive strength. Furthermore, it is determined that a single, unchanging and dominant load-case is most suited for TO optimisation. Using ANSYS Workbench, mass reductions of up to 69% compared to an initial, unoptimized geometry are achieved, reducing annealing times by an estimated 90%. Following this, the feasibility of manufacturing the resulting complex-shaped glass components is investigated though physical prototypes. Two manufacturing techniques are explored: lost-wax casting using 3D-printed wax geometries, and kiln-casting using 3D-printed disposable sand moulds. Several glass prototypes were successfully cast and annealed. From this, several conclusions are drawn regarding the applicability and limitations of TO for cast glass components and the potential of alternative manufacturing methods for making such complex-shaped glass components.@en

Phase change materials (PCMs) have already been used in buildings and building services for several decades, mostly integrated into walls or ceilings to passively increase the building’s thermal inertia, or integrated into the HVAC system for (pre-)heating or (pre-)cooling fresh air. More recently, the use of PCMs in facades is being explored for solar heating. This paper presents the results of a several years of research into the use of PCMs in rotatable Trombe walls and sun-shading for passive heating and cooling purposes. Simulations used a custom-made model of a room in Matlab/Simulink, in which all relevant heat transfer paths and mass components are accounted for. Once the behaviour of PCM was modelled, the model was connected with the optimisation platform modeFRONTIER to study the (best) performances under different scenarios. The results show that a significant reduction in the energy demand for heating and cooling can be achieved in different climates. The results also show that the shading and insulating effect of the solar wall have the highest impact on the reduction of the cooling respectively heating demand, followed by the thermal mass effect. The paper ends with the development of a prototype of a Trombe wall which was installed in an office at the Green Village (a living lab in Delft).@en

Architectural space layout has proven to be influential on building energy performance. However, the relationship between different space layouts and their consequent energy demands has not yet been systematically studied. This study thoroughly investigates such a relationship. In order to do so, a computational method was developed, which includes a method to generate space layouts featuring energy-related variables and an assessment method for energy demand. Additionally, a design of experiments was performed, and its results were used to analyse the relationship between space layouts and energy demands. In order to identify their relationship, four types of design indicators of space layout were proposed, both for the overall layout and for each function. Finally, several optimisations were performed to minimise heating, cooling and lighting demands. The optimisation results showed that the maximum reduction between different layouts was up to 54% for lighting demand, 51% for heating demand and 38% for cooling demand. The relationship analysis shows that when comparing the four types of design indicators, the façade area-to-floor area ratio showed a stronger correlation with energy demands than the façade area ratio, floor area ratio and height-to-depth ratio. Overall, this study shows that designing a space layout helps to reduce energy demands for heating, cooling and lighting, and also provides a reference for other researchers and designers to optimise space layout with improved energy performance. @en

The increase in global population, which negatively affects energy consumption, CO2 emissions, and arable land, necessitates designing sustainable habitation alternatives. Self-sufficient high-rise buildings, which integrate (electricity) generation and efficient usage of resources with dense habitation, can be a sustainable solution for future urbanisation. This paper focuses on transforming Europoint Towers in Rotterdam into self-sufficient buildings considering energy consumption and food production (lettuce crops) using artificial intelligence. Design parameters consist of the number of farming floors, shape, and the properties of the proposed façade skin that includes shading devices. Nine thousand samples are collected from various floor levels to predict self-sufficiency criteria using artificial neural networks (ANN). Optimisation problems with 117 decision variables are formulated using 45 ANN models that have very high prediction accuracies. 13 optimisation algorithms are used for an in-detail investigation of self-sufficiency at the building scale, and potential sufficiency at the neighbourhood scale. Results indicate that 100% and 43.7% self-sufficiencies could be reached for lettuce crops and electricity, respectively, for three buildings with 1800 residents. At the neighbourhood scale, lettuce production could be sufficient for 27,000 people with a decrease of self-sufficiency in terms of energy use of up to 11.6%. Consequently, this paper discusses the potentials and the improvements for self-sufficient high-rise buildings. @en

High-rise building optimisation is becoming increasingly relevant owing to global population growth and urbanisation trends. Previous studies have demonstrated the potential of high-rise optimisation but have been focused on the use of the parameters of single floors for the entire design; thus, the differences related to the impact of the dense surroundings are not taken into consideration. Part 1 of this study presents a multi-zone optimisation (MUZO) methodology and surrogate models (SMs), which provide a swift and accurate prediction for the entire building design; hence, the SMs can be used for optimisation processes. Owing to the high number of parameters involved in the design process, the optimisation task remains challenging. This paper presents how MUZO can cope with an enormous number of parameters to optimise the entire design of high-rise buildings using three algorithms with an adaptive penalty function. Two design scenarios are considered for quad-grid and diagrid shading devices, glazing type, and building-shape parameters using the setup, and the SMs developed in part 1. The optimisation part of the MUZO methodology reported satisfactory results for spatial daylight autonomy and annual sunlight exposure by meeting the Leadership in Energy and Environmental Design standards in 19 of 20 optimisation problems. To validate the impact of the methodology, optimised designs were compared with 8748 and 5832 typical quad-grid and diagrid scenarios, respectively, using the same design parameters for all floor levels. The findings indicate that the MUZO methodology provides significant improvements in the optimisation of high-rise buildings in dense urban areas.@en

Numerous studies have shown that architectural design affects energy performance significantly. However, the effect of space layouts on building energy performance has not been fully analysed. In this paper, we aim to study the effect of space layouts on energy performance. An office building was used as the reference, and 11 layout variants were proposed and compared for energy performance. Three climates (temperate, cold and tropical) were inspected, with three typical cities (Amsterdam, Harbin and Singapore). Dynamic simulation was conducted for the energy performance assessment integrating daylighting simulation with energy simulation. For each layout, two situations were simulated: one has no shading system, and the other one has an exterior screen for shading. Based on the simulation results, it is found that lighting demand is affected the most by the layout variance, and the resulting maximum difference (difference divided by the highest demand) happens in Harbin, being 46% without shading and 35% with shading. Regarding the sum of the final energy for heating, cooling and lighting, using a heat pump system, the maximum difference is 8% for the layouts both without and with shading system occurring in Amsterdam.

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Designing high-rise buildings is one of the complex tasks of architecture because it involves interdisciplinary performance aspects in the conceptual phase. The necessity for sustainable high-rise buildings has increased owing to the demand for metropolises based on population growth and urbanisation trends. Although artificial intelligence (AI) techniques support swift decision-making when addressing multiple performance aspects related to sustainable buildings, previous studies only examined single floors because modelling and optimising the entire building requires extensive computational time. However, different floor levels require various design decisions because of the performance variances between the ground and sky levels of high-rises in dense urban districts. This paper presents a multi-zone optimisation (MUZO) methodology to support decision-making for an entire high-rise building considering multiple floor levels and performance aspects. The proposed methodology includes parametric modelling and simulations of high-rise buildings, as well as machine learning and optimisation as AI methods. The specific setup focuses on the quad-grid and diagrid shading devices using two daylight metrics of LEED: spatial daylight autonomy and annual sunlight exposure. The parametric model generated samples to develop surrogate models using an artificial neural network. The results of 40 surrogate models indicated that the machine learning part of the MUZO methodology can report very high prediction accuracies for 31 models and high accuracies for six quad-grid and three diagrid models. The findings indicate that the MUZO can be an important part of designing high-rises in metropolises while predicting multiple performance aspects related to sustainable buildings during the conceptual design phase.@en

A large number of studies suggest that employees in an open-plan office are disturbed during their day-to-day work for a variety of reasons. In particular, disturbances caused by speech are difficult to estimate during the early design phase. Multi-agent models provide a way to predict the behaviour of diverse systems, including occupants. We introduce a framework combining multi-agent modelling with acoustic simulation to evaluate spatial layout at the early design phase. The framework provides results by evaluating trajectories and interactions between the agents throughout the simulation. The results are presented in the form of acoustic performance of the layout on the spatiotemporal scale along with performance matrices. The framework was assessed through a case study of an architectural office in Amsterdam.@en

This paper investigates the stiffness and the durability of a composite panel that consists of thin glass as outer layers and a 3D printed core element from recycled PET. Thin alumino-silicate glass, mostly used for displays in computers, tablets and smartphones, is known for its flexibility, durability and high bending strength. However, for building applications, the high flexibility of thin glass may cause serviceability issues. Therefore, to stiffen thin glass, a composite concept of thin glass with a 3D printed core is developed. The core element of this panel consists of 3D printed recycled PET. The use of recycled PET has been taken into account, due to the increase of plastic waste for the next 30 years. A combination of both materials allows for a much stiffer composite panel and reduction in weight of 71,9 % compared to a normal double glazed window panel. This paper presents an overview of the durability of the composite panel. The durability aspects for this exploratory study are UV radiation, elevated temperature and fire. The UV radiation tests showed that the applied acrylic adhesive ensures for a good adhesion, which allows reaching high load bearing capacity. Also, these tests showed that recycled PET changes into a yellowish color and becomes more brittle. The temperature tests showed that at an elevated temperature of 80 ⁰C, recycled PET loses its stiffness and strength and cannot sufficiently take up forces when loaded. The fire experiments showed that the recycled PET core melted fully during the fire exposition.@en

As one of the most important design tasks of building design, space layout design affects the building energy performance (BEP). In order to investigate the effect, a literature review of relevant papers was performed. Ten relevant articles were found and reviewed in detail. First, a methodology for studying the effects of space layouts on BEP were proposed regarding design variables, energy indicators and BEP calculation methods, and the methodologies used in the 10 articles were reviewed. Then, the effects of space layouts on energy use and occupant comfort were analysed separately. The results show that the energy use for heating, cooling, lighting and ventilation is highly affected by space layouts, as well as thermal and visual comfort. The effects of space layouts on energy use are higher than on occupant comfort. By changing space layouts, the resulting reductions in the annual final energy for heating and cooling demands were up to 14% and 57%, respectively, in an office building in Sweden. The resulting reductions in the lighting demand of peak summer and winter were up to 67% and 43%, respectively, for the case of an office building in the UK, and the resulting reduction in the air volume supplied by natural ventilation was 65%. The influence of other design parameters, i.e., occupancy and window to wall ratio, on the effects of space layouts on BEP was also identified.@en

Currently 40% of EU's final energy consumption is attributed to buildings. Achieving the EU's climate targets would entail improved strategies in designing nearly Zero Energy Buildings. This research aimed to create an integrated decision-making strategy in designing ZEBs with the use of multi-objective optimization of building design and construction parameters for minimizing energy demand, while maximizing energy production and adaptive thermal comfort. Goal is to define which parameters have the highest impact and potential for further optimization and to offer an alternative to current stepped strategies such as the New Stepped Strategy. The proposed integrated approach is applied on a typical high-rise office building in Greece. Energy simulations with DesignBuilder are used as benchmark for the optimization run with EnergyPlus through Rhino and Grasshopper software via the plug-ins Honeybee and Ladybug, coupled with modeFRONTIER. For the first optimization round, the investigated parameters are: window-to-wall ratio, wall U-value, glazing construction U-value, glazing g-value, air-tightness of the facade, cooling set-point of the mechanical cooling system and PV facade surface area. For the second round, the parameters of window-to-wall ratio, shading area and PV surface area are adapted for four facade orientations. The optimizations resulted in a building with an annual final energy reduction of 33%.

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