Building automation and control systems (BACS) are central to energy performance and occupant comfort in non-residential buildings. Comfort is inherently multi-domain, including thermal, visual, acoustic, and air quality requirements. Multi-domain BACS involves frequent trade-offs across domains when conflicting control actions arise, such as providing glare control versus daylight availability. Yet existing occupant-centric control research treats building services in isolation, and prior multi-domain comfort reviews rarely examine how multi-domain demands are integrated into BACS decision logic across services. We conducted a systematic review of 43 studies to examine how multi-domain occupant demands are represented and operationalized in BACS. Across the evidence base, thermal comfort is universal, while visual and air quality are frequently included. Acoustics is rarely addressed due controllability constraints. Most studies remain unimodal in their demand representation, even when multiple domains are in scope. Integrated BACS implementations are therefore largely built on within-domain formulations. Multimodal demand models that encode cross-domain and combined effects are uncommon and are rarely implemented in integrated BACS. Rule-based strategies dominate multi-domain controllers. Optimization-based and learning-based controllers are also used, but they often rely on fixed weights or reward terms that make trade-offs difficult to interpret. In addition, actuator choice is rarely made explicit when multiple services can achieve the same target state. Future research should benchmark unimodal and multimodal demand formulations under comparable control contexts, extend bottom-up multimodal models beyond thermal and air quality into integrated BACS, especially for façade control, and develop transparent, preference-aware policy designs that make priorities and service actions understandable.

Smart dynamic building technologies can help to significantly reduce operational energy and carbon emissions. However, human acceptance remains a significant barrier, particularly for switchable glazing used in smart windows. This study examines how users are affected by the speed and direction of transitions in the transparency of fast switchable glazing, specifically dynamic liquid crystal technology under overcast sky. Perceptual and behavioural data including facial action units, were collected through an experimental campaign in a semi-controlled environment where the glazing transparency was transitioned at two rates (1 and 10 s). It was found that user perception remained consistent regardless of transition speed or direction, but override behaviour was influenced by both factors. In the absence of glare, user overrides were primarily driven by the transition direction, with more users reacting to transitions from dark to clear. Faster transition rates led to an increase in user overrides for both transition directions. Unlike those who did not override, users who overrode the automated glazing control strategy had a negative perception of the visual environment and the window control system. Users directed their gaze more towards the glazing when this was transitioning, suggesting possible distractions. Users were clustered based on their background knowledge and reported preferences. These clusters showed a good correlation with the override delay times. However, the agreement with actual behaviour was low, indicating that a larger number of variables and clusters should be tested to predict user behaviour. Nevertheless, clustering users highlighted the importance of considering individual differences for interaction strategies.

In recent years, several studies have assessed the influence of automated façades on energy savings, IEQ, and occupant satisfaction. However, discrepancies exist between the expected advantages of automated façades predicted in research and the actual benefits observed in real-world tests. To assess how automated façade operation enhances building performance, in particular within office building contexts, this study reviews and analyzes current evidence on the influence of automated façades. In this review, 91 studies were identified presenting evidence of their performance. A total of 34 studies investigated performance in laboratory settings, 23 in real office buildings, and 34 in simulations. Only 13 laboratory studies and 17 real office building studies included human participants. Visual and thermal quality were the main indoor environmental domains investigated, with limited exploration of others. Existing studies show large variability in contextual factors (e.g., type of shading and control) or experimental designs (e.g., different benchmark scenarios), hindering the comparison of results. Consistent evidence shows the potential of automated façades for energy savings, particularly in lighting and cooling demands, which outperform manual control systems. Automated controls are more effective in reducing excessive daylight and glare, while evidence of the impact on thermal and air quality remains limited. Regarding occupant satisfaction, evidence is unclear since, in some cases, occupants prefer manually controlled façades and, in others, automated ones. Further research is suggested on human-centered studies in real office buildings to capture occupant behavior and preferences while exploring solutions that dynamically identify and integrate factors affecting occupant interaction with buildings.

To reduce material waste and carbon emissions, the manufacturing industry of exterior window frames (aluminium, PVCu and timber) could transition from recycling to remanufacturing. This paper investigates to what extent reclaimable window frames from 1970 to 2010 are technically upgradable to meet current thermal and airtightness requirements, and if the existing (linear) supply chains are able to perform these upgrades. To answer these questions, a multi-method approach was used. Historic window frame designs were retrieved from standard literature. These were assessed to see what minimum upgrades they require to comply to current regulations. Retrieved process models of the existing supply chains were then used to investigate to what extent the existing factories are able to perform these upgrades. The results show that based on the assessed historic window frames, it is possible to upgrade aluminium, PVCu and timber window frames of around 25 years old, depending on the window size. However, from a remanufacturing perspective, all three existing supply chains lack essential steps to perform these product upgrades. Also some existing manufacturing processes can't be used for remanufacturing, as they are designed to process unencased, individual profiles. This makes reclaimed encased frames incompatible with the first processes of the linear supply chains. PVCu and aluminium profiles are manufactured in respectively two and three factories, which is a notable impediment for re-finishing the profiles. Two identified opportunities for upgradability and remanufacturing are standardization of interfaces and modularity. Future multi-lifecycle circular window frame designs could benefit from further implementation of these design approaches.

Given the global challenges arising from climate change, relevant, promising methods to expedite the energy transition are essential. The integration of solar cooling technologies into façades represents an important option. Potential benefits of applying solar cooling technologies include conserving primary and conventional electricity sources, lowering peak energy demand to achieve cost savings, and offering environmental benefits. This study aimed to support the design team and stakeholders involved at the design and development stages with a framework that supports developing solar cooling integrated façades. This study adopted a participatory research methodology to identify, outline, and validate key decisions, information, and stakeholders supporting product design and development. The key study findings revealed that the integration of solar cooling technologies into façades should be considered at the conception stage, where the client, climate designer, building physicists, building service consultants, and architects were identified as key participants who should be involved in the decision-making process. The most critical information identified for supporting design decisions includes technology costs, performance and efficiency, cooling demand, and construction characteristics of the thermal envelope.

Additive Manufacturing with Varying Material Properties enables controlled spatial variation of material properties in 3D-printed components, facilitating custom-tailored characteristics, added functionalities and reduced assembly processes. To promote this approach in building façade applications, this paper presents a novel framework for Additive Manufacturing with varying material properties using a thermosetting reactive polymer, specifically polyurethane. By dynamically changing the polyurethane’s chemical composition, the material properties can be precisely controlled. The framework’s individual aspects, including the material, hardware setup and computational system, are described in detail. Additionally, the research explores the implementation of material transitions with this framework, highlighting three different modes (horizontal, vertical and multi plane) and their impact on print time and material consumption. The paper concludes by discussing the potential of this approach for building façade applications, addressing current challenges and outlining future research directions.

Integrating solar cooling technologies into building façades can play a crucial role in reducing reliance on conventional cooling systems. However, incorporating various aspects at the early stages of a project can be challenging for designers due to the diverse types of information, steps, and decisions required. This study aimed to develop strategies for design teams to facilitate the early-stage design and evaluation of building façades integrating solar cooling technologies. The strategies were developed using a research-through-design methodology, considering the Spanish context and a proposed evaluation set-up to assess techno-economic feasibility. The development of strategies involved mapping the design and evaluation of solar cooling integrated façades by identifying and relating key processes, inputs, outputs, design decisions, and tools within key design stages. Consequently, a systematic design and evaluation process was carried out, including the identification and assessment of potential integration scenarios for solar electrically driven and thermally driven technologies based on relevant techno-economic criteria. The findings indicate that water-cooled vapor-compression chillers (VCC), combined with photovoltaic (PV) panels as an electrically driven solution, were the most relevant option for the selected case. Additionally, the developed strategies revealed that early-stage decisions significantly impact later processes, as they involve a greater number of steps, required information, and design choices. These strategies serve as guidelines to support designers in adopting a systematic design approach, helping to manage the complexities associated with processing diverse technical and economic information. Providing such structured methodologies to professionals with limited experience in solar cooling technologies is crucial for enabling their broader application.

The European building stock demands urgent renovation due to the age of the buildings, their expected lifetime, and their excessive energy consumption, which accounts for more than a third of the EU’s total emissions. However, the complexities involved, such as time, costs, and structural modifications, often discourage clients, tenants, and occupants from undergoing a building renovation process. Textile membranes, despite their long history in various architectural applications, have only been employed in façades in the last decades. Their intrinsic properties, such as lightness and flexibility, together with rapid assembly and low maintenance make these materials particularly suitable for façade retrofitting. Therefore, they are worth exploring as a way to promote the development of lightweight and easy-to-assemble façade products that could help overcome the current limitations of building retrofitting efforts. This paper aims to establish relationships between textile membranes and potential building retrofit applications. To this end, this study builds on the categorization of traditional façade retrofit strategies and proposes a new classification for textile façade retrofit products. The methodology includes a comprehensive literature review of textile properties and characteristics, along with a thorough assessment through case studies, of membrane use in façade applications. A sequential investigation leads to the main outcome of identifying three clear pathways for the development of new textile-based façade products for building retrofit.

Given the urgent sustainability goals, the construction industry is actively seeking renewable and recyclable biobased materials. In this research, cellulose and lignin, the most abundant biopolymers on earth, were studied as fundamental building blocks to create an innovative bio-based material to 3D print elements for the construction industry. Having obtained a 3D printable paste, the study presented in this paper delved into the 3D printing possibilities by using a clay extruder mounted on a robotic arm. A window frame was used as test case, addressing the existing gap in replacing or enhancing current window frames. To better understand the printing process and explore various geometric configurations, a section of a window frame was printed as proof of the concept.

The present research proposes a framework to design and evaluate façade products integrating solar cooling technologies (SCTs), applied in an office building in a Southern Europe region. The building comprises various types of façade elements, such as opaque walls, glazed curtain walls, overhangs, and balconies. Key regulatory measures were implemented considering national energy saving regulations. The results represent annual energy consumption (kWh/m2/year) and the average daily cooling demand in Summer Design Week (kWh/day) of the simulated base model. This energy consumption lies within range of a previously simulated generic office and the average annual energy consumption of office blocks. Potential scenarios for integrating SCTs were outlined and evaluated using the solar fraction (SF) as an indication to measure the potential performance of the system based on nominal efficiencies, providing an initial reference of its ability to meet cooling demands, an essential step in early design stages. Scenarios per configuration related to double-effect chillers with evacuated tubes collectors and water-cooled vapor compression chiller and photovoltaic (PV) panels were the only one having an SF value of 1 or more, meaning that they can be able to handle the required cooling demand. Future steps should consider a second level of technical evaluation of scenarios having SF values of 1 or more, which should involve aspects related to how to physically integrate the technology, considering compactness and space usability and also maintenance requirements, among other relevant criteria.

The application of façade products integrating solar cooling technologies tends to be one of the promising options to be considered for challenges related to the increase in global demand for cooling in the built environment. Accordingly, the technological innovation of such products represent an essential task to be taken into account for meeting the future cooling demand in buildings. However, selecting the right technology and tackling technical and product-related aspects in the context of solar cooling can be challenging, since each technology is different from one another in terms of their working principles. Furthermore, developing such building products can be a complex endeavour, due to the involvement of various components. This paper aims to propose a conceptual approach for designing and developing façade products integrating solar cooling technologies. Proposing this approach required establishing a matrix of key attributes and criteria affecting technological selection through referring to identified key perceived enabling factors by expert interviews in an earlier stage of the study. The outcomes of this study outlined various attributes, such as product performance and efficiency as well as compactness and space usability, that can be used in product development of solar thermally and electrically driven systems, in order to ensure to support the widespread application.

Background. The automated operation of facades in buildings can positively impact indoor environmental quality (i.e. thermal regulation, acoustic control, air quality, and access to daylight and outside view) whilst reducing cooling, heating, and lighting energy demand. Conversely, several studies have also pointed out that the automated operation of dynamic façades can be disruptive to occupants and a source of discomfort when it does not meet occupant requirements. A number of factors affect occupant requirements regarding façade operation. However, the preference with which individual occupants perceive these requirements, in particular window visual effects, is yet to be understood, and it could inform better user-centred controls of automated facades. [...]

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.

People in cities are often exposed to complex mixtures of sounds, some originating from nature along with some created by human activities like traffic noise, sounds of industrial machinery, or music. This research aimed to study how the acoustic environment of a university campus is perceived by people. The procedures for soundscape data collection and analysis were based on the ISO 12913 series. 30 volunteers divided into four groups participated in a “soundwalk” at the campus of the architecture school in Detmold, Germany, filling out questionnaires while sound measurements and recordings were being taken. After the soundwalk, the data from the questionnaires, sound measurements, recordings, pictures and videos were analyzed. The findings suggest that people’s perception of sound is susceptible to the context, as participants seemed to shift their preference according to the ongoing activities that drew attention, such as a construction site, sounds from children playing, music and groups of people. The results provide new evidence and insights about the acoustic environment and the soundscape of the university campus and can inform stakeholders to improve environmental quality.

The first issue of volume 11 of JFDE elaborates on several topics related to façade design and engineering, focusing on façade systems, their construction, properties, and performance.

The topic of prefabrication in façade construction is one of the themes emerging from this issue. The importance of prefabrication is growing in the building industry as it has the potential to improve productivity by allowing faster, high-quality, and cost-effective construction while reducing risks related to onsite construction. Different articles touch on this topic from varying perspectives. In the context of decarbonization and the large number of buildings to be renovated, prefabrication for energy retrofits is a relevant topic. One notable article presents the development and evaluation of prefabricated timber-based façade modules. The results showed significant energy savings and effective vapor release of the prefabricated façade system. Furthermore, prefabrication and pre-engineering of systems require a paradigm shift in design and engineering practices towards more integrated approaches. A Kit-of-Part (KoP) approach to façade design employed by the authors of a different article enables an architect-led design team to validate design options through digital design tools based on a pre-engineered set of components. Information about the products included in the tool includes performance, cost, and environmental impact.

Focusing further on the properties of façade components, a paper in this issue investigates large-scale applications in building design regarding the aluminum used in façades and underlines the environmental benefits to be gained from reducing the use of raw materials, with particular emphasis on a sustainable approach to façade design. Finally, the issue addresses shading as an essential component of façade function, examining the influence of different shading devices on both performance and aesthetic aspects of the façade.

Overall, the issue provides insights into contemporary trends in façade design, emphasizing the role of pre-engineering and evaluating façade components in contributing to the future of the construction industry.

Residential buildings in the Kingdom of Saudi Arabia (KSA) contribute to nearly half of the overall electricity consumption in the building stock, highlighting their significant role in energy consumption. While an upgraded energy code has been established and enforced for new buildings, existing buildings continue to operate at the same level of energy consumption. Therefore, there is a need for further energy upgrades in existing buildings. This study evaluates the energy savings potential of various energy retrofitting measures for a case study in Jeddah, KSA. Data from previous studies and current practices were collected and analyzed. Different energy upgrade measures, such as windows replacement, wall insulation upgrade, roof insulation upgrade, and air conditioning unit replacement, were selected and evaluated using a digital simulation tool called Design-Builder. The simulation results were compared to understand the potential percentage of energy savings. The average annual energy consumption (AAEC) was used as the primary performance indicator to compare the energy savings among the scenarios. The results demonstrate significant reductions in energy consumption for the proposed scenarios. Furthermore, the study examined the significant impact of uncertainties, specifically, the infiltration rate and AC setback temperature, on AAEC. In conclusion, the proposed scenarios have the potential to achieve substantial energy savings, ranging from 25% to 66%, depending on the number of energy retrofitting interventions employed. The findings of this study can serve as a useful reference for similar energy retrofitting projects.

Multi-Material Additive Manufacturing (MMAM) is an emerging manufacturing approach that is gaining interest in architecture and construction as an expansion of Additive Manufacturing. Hereby, different materials or material properties are combined in a single additive process in order to create objects that are composed of multiple materials. Ultimately, this approach introduces a new way of manufacturing and building, where assembly is no longer a necessity in order to combine multiple materials. Moreover, different potentials can be derived from the use of MMAM. Leading towards components with heterogeneous material composition and a high degree of adaption towards structural, environmental, and design criteria. This work provides an overview of the current state of MMAM in architecture and construction. Different processes and materials which have been reported are discussed and potentials, which emerge through the use of MMAM are described using specific use-cases.

The global attention to solar cooling systems has increased during the last years as a result of the expected growth in the world cooling demand. Such systems encompass the use of renewable energy as the main driver for mitigating indoor temperatures. Currently, some of these technologies are mature enough for their commercial application in buildings. Building facades present high potential for the integration of such technologies. This is because of their direct effect on the indoor comfort of buildings, and also their ability to provide external surfaces exposed to the sun radiation. However, there are different challenges affecting the widespread application of solar cooling integrated façades. This paper aims to identify and categorize these challenges through conducting a comprehensive literature review. A literature review was conducted on scientific papers published in conference proceeding and scientific journals, through considering two databases, namely Scopus and Web of Science. Then the study suggested three main potential dimensions that should be tackled and integrated when supporting the widespread application of the façade integration a particular solar cooling technology. The dimensions include technical, financial, as well as process and stakeholder related aspects. Such proposed dimensions represent an initial step for identifying important aspects to be considered for supporting the product widespread application in the built environment.

The main bottleneck during the manufacture of complex geometry thin-walled GFRC structures is the time taken to make the timber or CNC machined moulds for each panel. Complex geometries are comprised of many unique panel forms and the extensive time and high costs of their manufacture often prevents their architectural intent from being fully realised. A novel mould-making process is proposed that uses a state-of-the-art flexible table with computer-controlled actuators to create free-formed geometry, fast-curing, dual-density, polyurethane moulds. This mould-making process was successfully tested by using sprayed GFRC to manufacture 9 different double curved intermediate moulds for a 10 m high GFRC self-supporting, thin-walled hyperbolic shell, with 12 mm thick panels at the base of the structure. The completed structure showcased the effectiveness of the novel mould-making process by reducing the production time from an estimated 100 days to 10 days. The primary outcome was the development and application of a new manufacturing method capable of casting complex geometry thin-walled GFRC panels with good surface quality that was suited to more rapid, cost-effective and automated large-scale production.