The implementation of Nearly Zero-Energy Buildings (NZEB) renovation packages in Europe needs to be accelerated to meet the current decarbonization goals. To achieve this level of performance, building renovation strategies should shift towards solutions that incorporate a multitude of passive and active components, increasing the complexity and costs of the execution. Moreover, it requires the involvement of different stakeholders of the building supply-chain, resulting in additional difficulties in communication and coordination processes. To address this challenge, the present study aims at mapping the renovation process in digital platforms and addressing the respective bottlenecks. In terms of renovation process, several digital platforms were analysed to identify the type of information that the stakeholders require during the different renovation phases. By structuring the information along the renovation process phases, the different stakeholders can identify when the information can be provided and how the different type of information links to each other.

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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.@en

Adaptive façades are multifunctional systems that are able to change their functions, features, or behaviour over time in response to changing boundary conditions or performance requirements. As one of the significant developments in the façade industry over the last decade, the adaptive façade offers an intelligent solution that can decrease energy consumption and potentially increase users’ comfort in a building. From an engineering perspective, these advanced technologies aim to improve the overall performance of the building while generating a better indoor environment for the users, but unfortunately, investigations show that this goal is not always achieved. This is why, to bridge this performance gap, we embark on a change of perspective in façade design, from a technology-centred to a human-centred one. This research emphasizes that, with their changeability aspects, adaptive façade technologies offer unique potential, although the design of such façades requires a deeper understanding of users. With this as its focus, this paper aims to identify the factors affecting the user experience in a working environment, considering the interactions of the user with building services and façade systems from a holistic point of view, in which façade-user relationships are to be distinguished, towards the larger aim of developing a human-centred approach for adaptive façade design.

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Several studies performing building simulations showed that the automated control of façades can provide higher levels of indoor environmental quality and lower energy demand in buildings, in comparison to manually controlled scenarios. However, in several case studies with human volunteers, automated controls were found to be disruptive or unsatisfactory for occupants. For instance, automated façades became a source of dissatisfaction for occupants when they did not fulfil individual environmental requirements, did not provide personal control options, or did not correctly integrate occupant preferences with façade operation in energy-efficient controls. This article reviews current evidence from empirical studies with human volunteers to identify the key factors that affect occupant response to automated façades. Only twenty-six studies were found to empirically investigate occupant response to automated façades from 1998 onwards. Among the reviewed studies, five groups of factors were found to influence occupant interaction with automated façades and namely: (1) personal factors, (2) environmental conditions, (3) type and mode of operation, (4) type of façade technology, and (5) contextual factors.. Overall, occupant response to automated façades is often poorly considered in research studies reviewed because of the following three reasons: (i) the lack of established methods or procedures for assessing occupant response to automated façade controls, (ii) poor understanding of occupant multi-domain comfort preferences in terms of façade operation, (iii) fragmented research landscape, on one hand results are mainly related to similar contextual or climatic conditions, which undermines their applicability to other climates, while on the other hand the lack of replication within the same conditions, which also undermines replicability within the same condition. Lastly, this paper suggests future research directions to achieve a holistic and more comprehensive understanding of occupant response to automated façades, aiming to achieve more user-centric automated façade solutions and advanced control algorithms. In particular, research on the impact of personal factors on occupant satisfaction with automated controls is deemed paramount.@en

A bioreceptive material allows for biological content (biofilms) to grow on it, without necessarily affecting the material itself. If a bioreceptive concrete could therefore be integrated into a building façade, it could lead to green façades that do not need additional technical systems. As part of previous research by the authors, a promising bioreceptive concrete mixture was formulated. The aim of this research is to develop this concept by using the previously developed mixture to create a bioreceptive concrete façade panel prototype, made using commonly available materials, that can direct where the biological growth takes place. The latter is done by combining the bioreceptive concrete with a non-bioreceptive (UHPC-based) concrete in the same panel, through a two-stage pouring process. A biofilm was developed on this prototype panel and results show that full coverage of the bioreceptive parts of the panel can be achieved within two weeks under optimal growing conditions and biological growth can be directed. However, exterior survivability is an issue for now. The concept of bioreceptive façades therefore shows promise, yet further investigation into improving exterior survivability is necessary, while further research into the underlying ecology, material, economics, and climate effects is also necessary.@en

Increased urbanisation will put an increasing strain on our green spaces, which is expected to have a significant effect on our physical and mental health, as well as the health of our ecosystems. As such it is important to integrate more green spaces in our urban fabric. One way of doing this is by making use of so-called bioreceptive concrete on our façades and other structures, which allows for biological growth to take place on the concrete substrate itself, without requiring any additional systems or maintenance. However, the challenge is to create an affordable concrete mixture that is sufficiently bioreceptive for biological growth to take place. As such, in our research we test four possible measures to make concrete more bioreceptive: changing the aggregate to CEC (crushed expanded clay), adding bone ash to the mixture, increasing the wcf (water cement factor) and using a surface retarder on the concrete. Of these measures, changing the aggregate to CEC (p = 0.024), the addition of bone ash (p = 0.022) and the use of a surface retarder (p < 0.001) were found to significantly increase bioreceptivity. Increasing the wcf factor, however, was not found to significantly increase bioreceptivity (p = 0.429). It was also found that whereas it was previously though a pH below 10 is necessary for biological growth to take place, this does not appear to be the case. Although further research under natural conditions is necessary, the creation of an inexpensive bioreceptive concrete looks to be feasible.@en

The concept of sustainability has risen in the last three decades, as a vehicle to guide our efforts to overcome major environmental and societal challenges such as global warming and environmental degradation. The built environment is responsible for about 40% of the global CO2 emissions, a fact that has led to countless debates, approaches, and new technologies for the design of our buildings, and especially, the building envelope. The goal of this paper is to explore the current role and the impact that sustainability has in the design of the building façade, based on the insights from practicing architects with relevant experience in the field. While we know of countless theoretical approaches and design theories to deal with sustainability, the point of view from practitioners has hardly been in the spotlight. So, the input for the assessment was obtained through a series of interviews with designers, representing 34 different architectural firms in the Netherlands, between January and April of 2020. The 34 interviews followed a semi-structured questionnaire comprising open-ended questions, structured around different themes concerning their façade design process. The present document showcases and discusses the results from the following questions: what is the role of sustainability in your façade design process? How does it influence the result? The exploration of the gathered information shows that within the broader scope of sustainability, circularity is the most mentioned set of aspects that currently have a clear impact on façade design, closely followed by energy related aspects, and further below issues related to the user, nature inclusion, and value. Furthermore, it is possible to identify different and sometimes clashing approaches derived from different notions of sustainability: some interviewees believe in permanence and timeless buildings, which leads to massive structures and detailing focused on ageing and durability; while for others it mainly revolves around using less raw materials and reuse/recycling potential of building components; which leads to light structures, with focus on connections aiming for total disassembly and material recovery. These, among others, should be regarded as possibilities to choose from a set of potential approaches, whose suitability should be carefully assessed to match each project brief, under the larger aim to design and build sustainable façades, buildings and cities.@en

The paper explores the potentials of shape memory alloys (SMAs) for the design of autoreactive façade systems without using additional external energy. The exploration is conducted and assessed through the design of a façade concept for the city of Athens in Greece, aiming to improve both the indoor and outdoor environment by means of a kinetic autoreactive system featuring a dual-seasonal function, with a focus on the building’s direct and indirect impact on the urban heat island (UHI) effect. The paper covers a demonstration of the methodology followed, using a feedback-loop logic informed by environmental and energy performance evaluation studies in Grasshopper to optimize the geometry and movement of the shading component. During the façade design process, a comprehensive and systematic computational toolset is being developed, targeted on the abovementioned performance evaluation studies. Through the development and assessment of the façade concept, the objective is to explore the potentials and limitations for the application of autoreactive envelopes in the façade design. At the same time, the aim is to exploit the possibilities and optimization potentials offered through the developed iterative computational workflows, by showcasing the methodology and interoperability logic of the digital tools used for the data interchange.@en

As a state-of-the-art green façade technology, building-integrated microalgae bioreactor has the potential to reduce buildings’ carbon footprint and energy consumption. The present study aims to address the knowledge gap in the energy and daylighting performance of algae photobioreactor façade. The paper first studies the effects of algae windows on building energy saving through simulation analysis of an office building in Mashhad, Iran, with a cold semi-arid climate. It also presents a multi-objective optimization framework for the optimization of the energy and daylighting performance of algae windows integrated with an office building facade. Two optimization metrics include maximum Useful Daylight Illuminance (UDI) (%), and minimum Energy Use Intensity (EUI) (kWh/m ²/yr), representing optimal daylighting and energy performance metrics, respectively. The results demonstrate that a microalgae window significantly reduces building energy consumption comparing with single-glazed, double-glazed, and water windows. The extent of energy savings varies with window size, algae density, and façade orientation. The proposed optimization framework helps increase the average values of energy performance metrics by 21.37%, 33.25%, 36.22%, 39.67%, and daylighting metrics by 4.60%, 14.43%, 13.34%,14.33%, in the north, south, east, and west, respectively and sequentially. Sensitivity analysis demonstrates that window size has the highest effect on two studied performance metrics for all orientations, while algae density has minimal effect on energy consumption and no considerable effect on daylighting performance. Building energy performance simulation is validated by ASHRAE140-2017.

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Bio-receptivity refers to the aptitude of a material to allow for the natural growth of small plant species on stony surfaces with minimum external influence. Despite the numerous associated environmental benefits, the growth of mosses and lichens on facades has always been viewed as a negative phenomenon due to the random and shabby growth conditions. This research dealt with the design of a self-sustaining bio-receptive concrete facade system with an aim to create a more sustainable and green concrete for the construction industry. The research used surface geometry as a design variable to facilitate moss growth on concrete panels in an ordered and systematic manner. The exercise was an attempt to not only address the functional aspect of bio-receptivity but also its aesthetical quality, which has a primary influence on people’s perception of bio-receptivity and can promote mass use of this type of concrete material. The research was conducted in a top-down approach, where first, through design by research, six distinctly designed concrete panels were fabricated using adapted material composition (blast furnace cement with 75% slag, 0.6 water/cement, sand 0–4 mm and gravel 5–8 mm) as the boundary condition. The concrete mixture together with no curing policy resulted in highly porous concrete panels, suitable for bio-receptive properties. Next in the design validation phase, the influence of surface geometry/roughness on the water retention ability of the panels and the subsequent moss growth on the panels were evaluated through in vitro experiments. The water retention experiment of the panels was based on quantitative measurements for weight, relative humidity and temperature at several time intervals. The moss-growing experiment was carried out within an ideal greenhouse condition where the panels were initially inoculated with moss spores; the results were based on qualitative observation for a period of 4 months. According to the comparative analysis of these results, with the same material composition, Panel 2 showed the highest bio-colonization owing to its prominent surface geometry, whereas Panel 5 showed the least bio-colonization owing to its plain surface despite high absorption capacity. Thus, the role of geometry has been extensively proven in this research and as an outcome a set of general design guidelines have been formulated for a self-sustaining bio-receptive concrete facade panel, using geometry as a design variable for bio-receptivity.@en

The aesthetic of our built environment is perceived as an important aspect to consider for the design of human-centred cities, but a problem quickly arises in the presence of clashing conceptions of what we understand to be aesthetically pleasing. This paper adds to this discussion, by exploring architects' aesthetic preferences in façade design, aiming to include design practitioners in a debate that so far has remained largely academic. Thus, the goal of the study was to identify relevant aspects, based on a series of semi-structured interviews with practitioners representing 34 architectural firms from The Netherlands, carried out from January to April 2020. It was possible to identify two major types of aspects, and subsequent subgroups. Intrinsic aspects (compositional, plastic, detail design, and character) comprise aspects that are characteristic of a façade as an object, while extrinsic aspects (human, intellectual, and contextual connection) consist of relational features, determining the perceived beauty of a façade in terms of its connections with an outside agent. The main identified aspects in each one of the groups, the potential relations among them, and their relative relevance within the surveyed sample were part of the assessment, comparing the outcomes against previous results from the literature.@en

“Desigrated” presented an attempt to integrate heat prevention strategies with low-ex cooling technologies, namely the desiccant and M-cycle evaporative cooling technology, in the form of a façade system for high-rise office buildings. The project targets to provide an alternative cooling solution for the hot and humid climate context of Bangkok. The results from experiments by various researchers are used as assumptions in developing the system, which was then evaluated through numerical methods and dynamic simulations. Being one of the prominent dehumidification technologies, a composite silica gel heat exchanger (CCHE) was implemented as the primary part of the façade system, while the M-cycle technology would also be implemented as a secondary cooling technique to cool down the supply air. The evaluation shows a promising result with up to 36% energy consumption reduction in comparison with the conventional cooling system, presenting itself as a transitioning tool in order to replace refrigerant cooling.@en

The circular economy is a widely accepted concept that various governments have started to adopt. Still, a major consumer of resources, the construction industry, struggles to implement business models that answer to the opportunity and generate value beyond economical. At the same time, the industry is at a threshold of intensifying their production by industrialized manufacture. This type of construction offers practical benefits and should be developed whilst prioritizing a sustainably built environment. A circular economy business model (CBM) offers all stakeholders long term value and revenue whilst moving towards a sustainable environment. The business model canvas (BMC) is a tool to shed light on the essential characteristics of a CBM, its value, and alignment in a multi-life cycle perspective. It can contribute to accelerating circular innovation in construction. This study aims to provide an overview of archetypical CBMs in construction based on a literature review and a systematic coding exercise using the BMC. The archetypes found are used to describe the characteristics of industrialized manufacture in the various circular economy construction scenarios. @en

In the Kingdom of Saudi Arabia (KSA), residential buildings' energy consumption accounts for almost 50% of the building stock electricity consumption. The KSA's economy relies heavily on fossil fuel sources, namely oil reservoirs, whose depletion will negatively affect the future development of the country. The total electricity consumption is growing by approximately 5-8% annually, which would lead to oil production and oil consumption being equal in 2035. Therefore, residential buildings need further assessment as regards their current energy consumption. This research used a survey to explore current user behaviour in residential buildings' energy performance in the city of Jeddah, KSA. The findings of the survey show that several factors impact the energy performance in residential buildings. First, the buildings' thermal properties were found to be poorly designed. Second, the cultural aspects (family member role and generous hospitality), and the majority of users within the buildings preferring a room temperature of below 24 • C, requires a massive amount of cooling due to the climate conditions. Third, an increase in user awareness has helped to slightly improve residential buildings' energy efficiency. Knowing the current high-energy-consumption sources and causes, being able to define opportunities for thermal properties' enhancement, and increasing user awareness of how to achieve self-sustaining buildings are essential.@en

Increasing cooling demands in the built environment call for innovative technical solutions and systems for application in buildings. Cooling loads represent an important share of the total energy consumption in warm climates, especially in commercial and office buildings. Moreover, mechanical systems will still be needed in most cases to cope with cooling loads, even after considering passive cooling strategies in the design of the building and its façade. Solar cooling technologies present interesting assets, being based on environmentally friendly cooling processes, driven by solar and thus renewable energy. However, their application in the built environment remains greatly limited. This paper assesses several solar cooling technologies in terms of their potential for façade integration; aiming to promote widespread application in buildings throughout the development of integrated architectural façade products. The assessment is based on a state-of-the-art review and discussion of key attributes for façade integration of selected technologies; and a qualitative evaluation of their suitability to respond to main product related barriers for the integration of building services identified in an earlier work by the authors. The cooling principles behind the operation of the assessed technologies have been extensively presented in the literature, so this paper focuses exclusively on key aspects to overcome barriers related to the technical feasibility, physical integration, durability, performance, and aesthetics of future integrated concepts. Results show that the suitability of the assessed technologies varies according to each particular barrier. Hence, no technology currently fits all required aspects. Nonetheless, the use of thermoelectric modules and compact units based on absorption technologies are regarded as the most promising for the development of either integral building components, or modular plug & play systems for façade integration. In any case, this is heavily conditioned to further efforts and explorations in the field to overcome identified challenges and knowledge gaps.@en

Cooling demands of commercial buildings present a relevant challenge for a sustainable future. They account for over half of the overall energy needs for the operation of an average office building in warm climates, and this situation is expected to become more pressing due to increasing temperatures in cities worldwide. To tackle this issue, it is widely agreed that the application of passive strategies should be the first step in the design of energy efficient buildings, only using active equipment if it is truly necessary. Nonetheless, there is still further need for information regarding the potential limits derived from their application.
This paper explores the effectiveness of selected passive cooling strategies in commercial buildings from warm climates, defining performance ranges based on the assessment of multiple scenarios and climate contexts. This task was conducted through the statistical analysis of results from documented research experiences, to define overall ranges and boundary conditions; and through software simulation of selected parameters to isolate their impact under a controlled experimental setup. General findings showed that the mere application of passive strategies is not enough to guarantee relevant savings. Their effectiveness was conditioned to both the harshness of a given climate and different building parameters. Specific recommendations were also discussed for the selected passive strategies considered in the evaluation.@en

Small-scale systems and integrated concepts are currently being explored to promote the widespread application of solar cooling technologies in buildings. This article seeks to expand application possibilities by exploring the feasibility of solar cooling integrated façades, as decentralized self-sufficient cooling modules on different warm regions. The climate feasibility of solar electric and solar thermal concepts is evaluated based on solar availability and local cooling demands to be met by current technical possibilities. Numerical calculations are employed for the evaluation, considering statistical climate data; cooling demands per orientation from several simulated scenarios; and state-of-the-art efficiency values of solar cooling technologies, from the specialized literature. The main results show that, in general, warm-dry climates and east/west orientations are better suited for solar cooling façade applications, compared to humid regions and north/south orientations. Results from the base scenario show promising potential for solar thermal technologies, reaching a theoretical solar fraction of 100% in several cases. Application possibilities expand when higher solar array area and lower tilt angle on panels are considered, but these imply aesthetical and constructional constraints for façade design. Finally, recommendations are drafted considering prospects for the exploration of suitable technologies for each location, and façade design considerations for the optimization of the solar input per orientation.@en

Given the need to reduce building sector related energy consumption and greenhouse gases (GHG), passive and sustainable buildings are a focal point. Simple methods and techniques, which use appropriate building design, material and systems selection, and reflect consideration of the local environmental elements, such as air and sun, provide thermal and visual comfort with less non-renewable energy sources. These techniques are referred to as environmental or bioclimatic design. There are two types of measures to be taken: passive and active. Passive principles exploit the design and properties of the building envelope to minimise or maximise the heat losses and heat gains respectively, to reduce the energy demand. In addition to passive, active measures such as heating systems and solar power technologies are used to produce and distribute the energy needed to achieve comfort of the occupants. The present chapter aims at giving an overview of design principles that result in more comfortable and energy efficient buildings. Passive and active design principles are in line with the environmental design concepts. The environmental design principles can be beneficial to the building performance, whether the design ambition is to have a comfortable and functional building with reasonable energy demand or goes as far as achieving sustainable standards such as zero-energy or passive house.@en

Increasing cooling demands in the built environment present an important and complex challenge for the design of sustainable buildings and cities. Even though the first course of action should always aim to reduce energy consumption through saving measures and passive design; these are often not enough to avoid mechanical equipment altogether, particularly in the case of office buildings in warm climate contexts. Solar cooling technologies have been increasingly explored as an environmentally friendly alternative to harmful refrigerants used in common air-conditioning systems; besides being driven by renewable energy. Nonetheless, building application remains mostly limited to demonstration projects and pilot experiences. The thesis discusses the suitability of solar cooling technologies in terms of their potential for façade integration, exploring current possibilities and identifying main constraints for the development of solar cooling integrated architectural products. The potential for façade integration is assessed considering both the architectural requirements for the integration of building services in the façade development process; and the potential climate feasibility of self-sufficient integrated concepts, matching current technical possibilities with cooling requirements from several climates. Although interesting prospects were identified in this dissertation, important technical constraints need to be solved to conceive fail-tested façade components. Furthermore, several barriers related to the façade design and development process need to be tackled in order to introduce architectural products such as these into the market. The identification and discussion of these barriers, along with the definition of technology driven development paths and recommendations for the generation of distinct architectural products, are regarded as the main outcomes of this dissertation, serving as a compass to guide further explorations in the topic under an overall environmentally conscious design approach.@en