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This paper provides an analysis of challenges and available solutions for exterior insulated panels suitable for deep energy retrofits of existing building envelopes. The analysis covers a review of available technologies that provide flexible retrofit insulated panels suitable for multiple climates and building typologies. Moreover, the paper proposes a new design for insulated retrofit panels that account for the majority of identified technical risks including cost, architectural diversity, climate variations, structural concerns, moisture resilience, air sealing, and water sealing. Additionally, the proposed design can be easily installed with minimal disruption to the occupants. A series of parametric and optimization analyses is carried out to identify the optimal design specifications for insulated panels suitable for deep retrofits of existing US housing stocks. The analysis results show that the optimal design criteria for the insulated panels can reduce heating and cooling energy consumption by up to 80% and HVAC capacities by 70%. Moreover, the results indicate that these insulated panels are highly cost effective for retrofitting US housing units located in cold climates. [ABSTRACT FROM AUTHOR]

The building envelope serves as a barrier against climatic conditions and as insulation to prevent energy waste within buildings. As global energy shortages become more pressing, the requirements for building envelopes are becoming increasingly stringent. Among the available technologies, phase change materials (PCMs) stand out for their high latent thermal energy storage and temperature stabilization capabilities. This paper reviews the recent advancements in PCM technology for building envelopes, starting with an overview of organic, inorganic, and eutectic PCMs, along with their respective advantages and disadvantages. The paper explores various incorporation methods such as shape stabilization, macroencapsulation, micro/nanoencapsulation, and solid–solid transition techniques. The integration of PCMs enhances thermal inertia, reduces thermal fluctuations, and delays heat peaks, presenting several multifunctional benefits. However, challenges such as fire hazards, potential toxicity, pollution, reduced mechanical performance, and higher initial costs persist. In light of these challenges, criteria for PCM integration in building applications are introduced. Additionally, the paper reviews recent hybrid technologies that combine PCMs with other novel technologies for building envelopes, including radiant temperature regulation systems, thermochromic windows, passive radiative cooling coatings, and others. It is shown that these PCM-integrated hybrid technologies significantly improve energy savings and indoor comfort. PCMs offer substantial potential for modern green building strategies and have further applications in other building contexts. Finally, the paper provides future prospects for studies in this field, aiming towards a green and energy-saving future. [ABSTRACT FROM AUTHOR]

Driven by environmental sustainability concerns, the integration of bio-based components in curtain wall systems is gaining traction in both research and the construction market. This paper explores the development and validation of a bio-based façade system within the Basajaun H2020 project (2019–2024). The project aimed to demonstrate the feasibility of introducing environmentally friendly bio-based components into the mature curtain wall façade industry. The paper focuses on identifying technological solutions for replacing key components such as frame profiles, insulation, and the tightness system with bio-based and less environmentally impactful alternatives, presenting the results achieved in the façade system design of the Basajaun project. These solutions aimed at creating a bio-composite-based curtain wall façade that adheres to the current building envelope standards and normative, implementing diverse façade typologies for vision panels, opaque sections, and integrated windows and, moreover, engineering the prefabrication process for industrialization and enabling wider market replication and simplified transport and installation. The results demonstrate that the Basajaun façade successfully integrates selected components and meets the performance requirements set by regulations: the façade is designed to withstand a maximum and typical wind load of 3.5 kN/m2 and a typical load of 1.5 kN/m2, the weighted sound reduction index obtained is Rw = 44 dB, and the thermal transmittance of the vision façade is 0.74 W/m2K while that of the entire opaque façade is 0.27 W/m2K (an additional internal wall is required to achieve the requested thermal transmittance)—the values are in accordance with reference standards and design requirements. However, questions remain regarding the workability of bio-based profiles as a commercially viable, ready-to-market solution that can replace traditional aluminum profiles in the curtain wall façade industry. [ABSTRACT FROM AUTHOR]

This paper addresses the research gap concerning the impact of thermal diffusivity on cooling energy consumption in buildings, specifically in the context of Saudi Arabia's hot climate. The objective is to determine the optimal thermal diffusivity of building walls for different climate conditions in Saudi Arabia to minimize the cooling energy consumption of residential buildings. The study analyzes four locations in Saudi Arabia, namely, Riyadh, Jeddah, Abha, and Tabuk, to understand the correlation between optimal thermal diffusivity and cooling degree days. The study includes numerical modeling using the finite-difference method and developing a calibrated building energy model of an existing residential building. Sensitivity analysis is conducted to evaluate the influence of thermal conductivity and heat capacity on cooling energy consumption. Correlation analysis is performed to assess the relationship between optimal thermal diffusivity and cooling degree days. The results highlight the importance of finding a balance between thermal insulation and thermal mass for energy-efficient buildings, considering the unique climate conditions in Saudi Arabia. Finally, this study considered the development of the Saudi Energy Conservation Code (SBC-602), which provides guidelines and regulations for energy-efficient building design in Saudi Arabia by recommending the selection criteria for the optimal thermal properties of building walls while considering the outdoor climate conditions. By aligning the findings of this study with the requirements and recommendations of the SBC-602, the study aims to contribute to the effective implementation of energy-efficient strategies in building design. [ABSTRACT FROM AUTHOR]

This paper examines the use of Phase Change Materials (PCM) in Building-Integrated Photovoltaic (BIPV) systems. To assess the performance of BIPV–PCM systems, the study employs a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis. The study features the advantages of using PCMs with BIPV envelopes. The benefits include lower heating and cooling requirements, shifted peak loads and increased thermal comfort. However, there are several challenges like heat loss and lower energy efficiency which needs to be addressed. Further, the potential for reduced PCM efficiency over time is recognized. The paper concludes by recommending further research on alternative PCM placement strategies, enhanced PCM formulations, gypsum board integration and the evaluation of PCMs combined with nanoparticles. [ABSTRACT FROM AUTHOR]

A large proportion of building energy consumption in tropical countries like Thailand primarily comes from air conditioning systems used to maintain the comfort level of building occupants. This paper aims to evaluate the performance of an alternative cooling system based on the evaporative principle in terms of thermal characteristics and energy consumption. A simulation model using computational fluid dynamics (CFD) software ANSYS version 16.0 and an actual experimental setup at the laboratory level were built to verify the results of the proposed cooling system. Additionally, factors that influence performance, such as components of the building envelope and the building's orientation, are considered. This research aims to demonstrate the impact of building envelope material and building characteristics on the energy usage in air conditioning systems and to propose an energy-efficient cooling system. The results demonstrate that the proposed cooling system can reduce the temperature inside the building. However, the characteristics of the building also affect the energy performance. Thus, the proposed cooling system, in combination with an efficient envelope material, can achieve energy savings of around 35–43%. Therefore, a combination of the proposed cooling system and optimal building design can ensure comfort for building occupants while saving energy. [ABSTRACT FROM AUTHOR]

Energy consumption in student dormitories, key living and study spaces, is a major concern for institutions and communities. This paper proposes a multi-objective optimization model to address the issue of incomplete single-dimensional analysis in existing research. Firstly, optimization was conducted separately for the external walls, windows, and roof to study different parts of the building envelope. Secondly, a student dormitory in a hot summer and cold winter region was used for a comprehensive optimization analysis. The study compared energy consumption, carbon emissions, and costs with the original building, showing a 31.79% reduction in energy savings (ESR), while carbon emission savings (CESR) and cost savings (CSR) increased by 57.18% and 15.58%. This study highlights the importance of selecting appropriate window configurations for sustainability. Optimized thermally broken Low-E glass windows save 5.6% in annual energy consumption compared to aluminum alloy double-glazed windows, with only a 0.03% increase in energy consumption and a 4.49% rise in costs. Long-term, optimized windows provide greater positive feedback for energy efficiency. This case study offers insights for retrofitting buildings with good wall performance but poor window performance and emphasizes the comprehensive decision-making authority of designers and policymakers in sustainable renovations. [ABSTRACT FROM AUTHOR]

The need to design buildings in compliance with the Paris Agreement goal requirements is urgent, and architects and engineers need to consider energy use and operational and embodied carbon requirements in doing so. Building envelopes will be an important element in the next generation of high-performance buildings and there have been significant advancements in recent years to develop building envelopes that help mitigate the building carbon emissions through energy-conserving low-embodied carbon or carbon-sequestering solutions. The key objective of this article is to present an overview of the state-of-the-art in the field of energy-efficient low-carbon buildings with a focus on envelope systems. This article provides a survey of the literature on energy use and carbon emissions of the United States building stock, presents recent advancements in energy-conserving building envelopes, and highlights reuse–reduce–sequester strategies that mitigate the embodied carbon of buildings. As materials are critical in reducing the energy consumption and carbon emissions of buildings, this paper also presents developments on diverse materials and building envelope solutions that have been effective in creating high-performance buildings, from insulation materials to phase-change materials and aerogels. Finally, the characteristics of a selected number of progressive net-zero-energy guidelines such as Passive House Institute (PHI) standards, Passive House Institute US (Phius) standards, the PowerHouse standard, and the BENG standard are discussed. The findings of this work highlight the increased focus on the design, construction, and engineering strategies that aim to mitigate the carbon emissions of buildings based on a holistic whole-life carbon mitigation approach. [ABSTRACT FROM AUTHOR]

Shanghai Tower has become a new landmark of Shanghai. In the current trend advocating green building and energy efficiency, considerations of wind loads and thermal characteristics of the perimeter structure of Shanghai Tower are crucial. This paper conducts comparative simulation studies on the wind environment of Shanghai Tower using Ecotect software, and stress analyses and thermal simulations of the perimeter structure using ANSYS software. The study compared three buildings' surface wind pressure distributions using models with equal-volume and circular cross-sections. We found that the unique exterior design of the Shanghai Tower results in a more regular and uniform distribution of wind pressure on its surface compared to both circular and square planar models, with a lower average wind pressure value. In addition, the stress analysis results indicate significant differences in deformation and stress distribution between the windward and leeward sides. Enhancing the bending moment detection of the peripheral structure and optimizing the layout of detection points are recommended. Thermal simulation results show excessive heat conduction flux in winter conditions, suggesting optimization using passive energy-saving methods such as light-sensitive thermal insulation materials during winter. This research is a reference for designing other super-tall buildings prioritizing low-carbon energy efficiency and structural safety. [ABSTRACT FROM AUTHOR]

Prefabricated temporary buildings are a promising solution for post-disaster scenarios for their modularity, sustainability and transportation advantages. However, their low thermal mass building envelope shows a fast response to heat flux excitations. This leads to the risk of not meeting the occupant comfort and HVAC energy-saving requirements. The literature shows different measures implementable in opaque surfaces, like vacuum insulation panels (VIPs), phase change materials (PCMs) and switchable coatings, and in transparent surfaces (switchable glazing) to mitigate thermal issues, like overheating, while preserving the limited available internal space. This paper investigates the energy and overheating performance of the mentioned interventions by using building performance simulation tools to assess their effectiveness. The optimization also looks at the transportation flexibility of each intervention to better support the decision maker for manufacturing innovative temporary units. The most energy-efficient measures turn to be VIPs as a better energy solution for winter and PCMs as a better thermal comfort solution for summer. [ABSTRACT FROM AUTHOR]

This paper details the comprehensive activities conducted in a laboratory setting to assess the structural health monitoring (SHM) of prefabricated building envelopes. Integrating sensors into building components like curtain wall facades poses challenges but offers opportunities for monitoring structural health, requiring compliance with regulatory standards. The research investigates the possibility of defining a kit of conventional and multi-parameter sensors integrated within the building envelope to monitor its behavior during the performance test conducted. The kit of sensors also includes Fiber Optic Sensors for effectively monitoring building envelope behavior and structural integrity. In this context, the European project InComEss (H2020-GA862597) aims to define a stand-alone solution for SHM using Piezoelectric Energy Harvesting Systems (PE-EHS) for façade monitoring through FBG/FOS system. After analyzing the main façade structural stress, a series of FBGs, accelerometers, and force washers were integrated within a 1:1 scale façade prototype and tested in a laboratory following the test sequence parameters required by the curtain wall standard EN 13830. The data collected were analyzed with the aim of monitoring the façade behavior before and after the tests. The results show that the façade's performance passed the assessing test criteria without reporting any damages. In addition, the outcomes demonstrated the effectiveness of the defined kit of multi-parameter sensors for the building envelope's SHM. [ABSTRACT FROM AUTHOR]

The world population increased from 1 billion in 1800 to around 8 billion today. The Population Division of the United Nations predicts a global population of approximately 10.4 billion people by the end of the century. That represents over 2 billion more people. Moreover, the global community is currently experiencing a precarious state due to the enduring repercussions of the COVID-19 pandemic across all sectors, including energy. Given the rising global population and the limited availability of primary energy resources, we must reach a balance between the demands of a growing human population and the planet's carrying capacity. The dreadful conflict in Ukraine has precipitated an enormous energy crisis. This crisis has served as a warning to the world population of how much it depends on this resource to survive. In France, the building sectors, specifically residential and tertiary, account for 45% of the total final energy consumption. It is the first energy consumer of the country and one of the most polluting (i.e., about 34% of CO 2 emitted by France). Consequently, we must consider alternative energy resource forms (i.e., substitution energy forms). Harvesting energy from the building envelope may be a viable technique for partially satisfying the electricity demands of building users. In this context, scientific research offers considerable potential for developing more innovative and efficient systems. This article aims to review the state-of-the-art of advances on the subject to orient and further optimize energy production systems, particularly electricity. This work addresses several points of view: it discusses the overall backdrop of the present study and introduces the subject; details the research strategy and procedures used to produce this paper; develops the state-of-the-art on the potential for generating or recovering power from the building envelope; presents the SWOT analysis of the earlier-described systems. Finally, it concludes by offering findings and viewpoints. [ABSTRACT FROM AUTHOR]

In the cold regions of China, the existing rural houses are widely distributed and in large numbers. There are widespread problems such as low thermal performance of building envelopes, high building energy consumption, and poor indoor thermal environments. Reducing the energy consumption of building heating by reforming the envelope structure can reduce the environmental pollution caused by heating. In this paper, the existing rural houses in Tongchuan City, Shaanxi Province are taken as the research object, and EnergyPlus software is used to calculate building heating energy consumption, and the schemes are compared and selected via the entropy value method. Based on a comprehensive benefit evaluation, the best scheme for the renovation of building envelopes of rural houses in Tongchuan City is put forward. The research results show that the energy saving rate of buildings can reach more than 50% after renovation. In the evaluation of energy saving, incremental cost, return on investment, carbon emission reduction and unguaranteed hours, the weights are 0.1915, 0.2104, 0.2312, 1755, and 0.187, respectively. The best renovation scheme for rural housing is as follows: the thickness of the XPS board is 90 mm for exterior wall insulation; the thickness of the XPS board is 80 mm for roof insulation; the window-to-wall ratio of additional sunspace is 0.6; and the type of exterior windows is a broken-bridge hollow aluminum window of 6 + 12A + 6 (mm). [ABSTRACT FROM AUTHOR]

The building envelope is the interface between the external atmospheric conditions and the indoor environment. It contributes to approximately 60%–70% of the heating and cooling load. The building envelope constitutes walls, fenestrations, and roofs from which thermal transfer from the roof is significantly very high compared to walls in low-rise buildings.This research paper aims to provide recommendations for energy-efficient roof design considering roof form, material, and external coating suitable for various climate conditions of India. The paper’s methodology consists of a literature review of related research papers, learnings from the roofing system of energy-efficient building case studies, and all possible energy-efficient roofing systems that would be simulated for energy efficiency and thermal comfort in five climate types of India. The expected outcome of this paper would be in the form of recommendations for roofing systems in different climate type and their potential for energy saving from the highest to the lowest. This research would be done in three stages viz, Step-1: Literature Review and case study of best practices: A review of the related literature and best practices examples would be done to formulate the maximum possible cases for the simulation. Step-2: The roofing systems, including building form, material (Thermal and insulation), and finishes (reflectance), would be simulated one by one for various climate types of India (composite, hot & dry, warm and humid, moderate and cold) to optimize energy efficiency and payback period. Step-3: Special roof types like Green roofs, cool roofs, Photovoltaic roofs, roof ponds, and the like are simulated and compared for their effectiveness in selected climate types. Based on the literature review, simulation results, and analysis, the recommendations are framed for energy-efficient roofing systems in the selected climate type with respect to heat transfer through the roof and thermal comfort.

This paper provides an analysis of challenges and available solutions for exterior insulated panels suitable for deep energy retrofits of existing building envelopes. The analysis covers a review of available technologies that provide flexible retrofit insulated panels suitable for multiple climates and building typologies. Moreover, the paper proposes a new design for insulated retrofit panels that account for the majority of identified technical risks including cost, architectural diversity, climate variations, structural concerns, moisture resilience, air sealing, and water sealing. Additionally, the proposed design can be easily installed with minimal disruption to the occupants. A series of parametric and optimization analyses is carried out to identify the optimal design specifications for insulated panels suitable for deep retrofits of existing US housing stocks. The analysis results show that the optimal design criteria for the insulated panels can reduce heating and cooling energy consumption by up to 80% and HVAC capacities by 70%. Moreover, the results indicate that these insulated panels are highly cost effective for retrofitting US housing units located in cold climates.

Driven by environmental sustainability concerns, the integration of bio-based components in curtain wall systems is gaining traction in both research and the construction market. This paper explores the development and validation of a bio-based façade system within the Basajaun H2020 project (2019–2024). The project aimed to demonstrate the feasibility of introducing environmentally friendly bio-based components into the mature curtain wall façade industry. The paper focuses on identifying technological solutions for replacing key components such as frame profiles, insulation, and the tightness system with bio-based and less environmentally impactful alternatives, presenting the results achieved in the façade system design of the Basajaun project. These solutions aimed at creating a bio-composite-based curtain wall façade that adheres to the current building envelope standards and normative, implementing diverse façade typologies for vision panels, opaque sections, and integrated windows and, moreover, engineering the prefabrication process for industrialization and enabling wider market replication and simplified transport and installation. The results demonstrate that the Basajaun façade successfully integrates selected components and meets the performance requirements set by regulations: the façade is designed to withstand a maximum and typical wind load of 3.5 kN/m2 and a typical load of 1.5 kN/m2, the weighted sound reduction index obtained is Rw = 44 dB, and the thermal transmittance of the vision façade is 0.74 W/m2K while that of the entire opaque façade is 0.27 W/m2K (an additional internal wall is required to achieve the requested thermal transmittance)—the values are in accordance with reference standards and design requirements. However, questions remain regarding the workability of bio-based profiles as a commercially viable, ready-to-market solution that can replace traditional aluminum profiles in the curtain wall façade industry.

Airflow in wall-to-wall junctions is known to have a major hygrothermal impact on building performance. However, current and validated modeling options to simulate such phenomena are limited. This paper develops and compares two numerical models to study the heat and moisture transfer due to air infiltrations through a prefabricated wall-to-wall junction. The first model explicitly accounts for the airflow with a pipe flow approach. The second model is a modification to a typical approach to simulate ventilated cavities in building envelope simulation tools and mimics the effect of the airflow through source terms. Both approaches were introduced in a heat and moisture transfer 2D finite element model. Additionally, laboratory measurements were conducted in a climatic chamber to validate the simulation results. Six scenarios were tested experimentally under steady-state conditions. These datasets were used to calibrate different parameters of the models, such as material properties, the junction air gap thickness, and the magnitude of the heat and moisture source terms. Both sets of numerical results provided reasonable agreement with the measurements. The first approach outputs more accurate temperature and relative humidity values than the second one. However, considering uncertainties, no method predicted a perfect fit with the relative humidity profiles. Close to the junction, the first method estimates better the relative humidity than the second one. This work provides guidelines to better model and account for wall junctions in building envelope simulators. • Airflow in wall junctions impacts hygrothermal performance, but is hard to model. • Temperature and humidity results from 2 models are compared to experimental results. • Pipe flow model better predicts temperature measurements than source term model. • Both models exhibited differences in relative humidity compared to measurements. [ABSTRACT FROM AUTHOR]

• The impact of insulation moisture ingress and thermal bypass are investigated. • 2D computational fluid dynamics is used to simulate thermal bypass in buildings. • Moisture ingress can increase thermal transmittance by a factor of ∼2.2. • Thermal bypass can increase thermal transmittance by a factor of ∼3.5. • Insulation detailing and installation can significantly impact heat loss in buildings. Improving the performance of buildings is a key part of the global effort to limit greenhouse gas emissions and reduce energy consumption. Reducing the designed thermal transmittance of building envelopes through the addition of insulation is one of the primary measures adopted in many nations aiming to address the building sector. In theory, these globally adopted measures to improve design should result in considerable energy savings. The reality however is different. And a mismatch between design and in-use performance has been widely cited. This performance gap is extensively attributed to changes in occupant behaviour – the rebound effect. Considerably less research has investigated technical performance gap rationale. This paper aims to address this literature gap by investigating two technical reasons why design and in-use performance might differ; namely: i) moisture presence in the building's insulation and ii) thermal bypass of the insulation system. The study uses a combination of thermal resistance analogies and computational fluid dynamics, to ascertain the extent to which compromised insulation would impact the performance of building envelopes. An increase in envelope heat loss results in an increase in a building's energy consumption, and hence its associated greenhouse gas emissions. The study concluded that, in extreme cases, the presence of moisture in the insulation layers can increase the thermal transmittance of highly insulated envelopes by a factor of 2.2, while closed- and open-loop thermal bypass can increase it by a factor of 3.5 and 3.7 respectively. Although these might be considered extreme cases, the results align with findings from several past studies that quantified the gap between in-situ and design thermal transmittance. The results suggest that, while ensuring building envelopes are designed with adequate levels of insulation is important, ensuring that the insulation is adequately installed is potentially of equal importance. [ABSTRACT FROM AUTHOR]

Rising urban temperatures, noise and air pollution, and the loss of biodiversity are pressing problems in cities worldwide that call for action at different scales to improve the livability of urban areas. This study focuses on the role that buildings and façade design play in the urban environment, exploring how their informed design might help mitigating these environmental issues at a local scale. It explores the field by means of a systematic review aimed at identifying the impact of façade design choices focusing on three main design variables: material, geometry, and vegetation in façades. Scopus and Web of Science databases were explored between 17 April and 20 April 2023, ending up with 121 scientific articles, then categorized and data-mined to allow for descriptive statistical analysis to discuss scientific results obtained via digital simulation or empirical measurements. Risk of bias was addressed through double revision of the gathered sample. This study ends with the identification of desirable façade attributes based on their reported impacts, in terms of material properties, geometric operations, and main vegetation parameters, which we discuss by outlining compatibilities and clashes between them to guide conscious building design decisions to improve the urban ecosystem. [ABSTRACT FROM AUTHOR]

[Display omitted] • A numerical analysis of a lightweight concrete roof with PCMs was performed. • Different roof configurations with and without PCM were numerically analyzed. • OpenFoam was used to model each roof configuration and code verifications were accomplished. • All roofs with PCM showed lower inner surface temperatures regarding the base case. • A maximum reduction of 65.5% in energy was achieved by case D-PCM-SP25Eu. The use of phase change materials in building envelopes has attracted the attention of researchers to minimize cooling and heating loads and for thermal comfort regulation. A research gap was found regarding the numerical analysis of lightweight roofs with PCM considering conjugate heat transfer. Thus, this paper aims to evaluate the thermal performance of a lightweight hollow concrete roof with a phase change material (PCM) in a subhumid climate. Three roof configurations with two PCMs were numerically analyzed through computational fluid dynamics. Simulations were conducted using the open-source code OpenFoam and were verified and validated with good agreements proving the confidence of the proposed methodology for building envelope design purposes. The roof configurations with fully-filled PCM exhibited the best thermal behavior, reaching higher temperature reductions between 1.4 °C to 2.0 °C, respectively, and reductions of indoor peak heat flux by approximately 47 % compared with the reference case. The roof fully-filled with an inorganic PCM with a melting temperature of 25 °C was the most energy-efficient roof configuration because it achieved the highest energy savings of 65.5 %, lowest electricity costs of 0.85–4.33 USD m−2, and lowest CO 2 emissions of approximately 18.31 kgCO 2 e m−2. The results demonstrated that the utilization of PCM into lightweight concrete roofs in subhumid climates is very promising. [ABSTRACT FROM AUTHOR]

Pattern-based building envelope is a modern style of contemporary facades. Architects may rely on imitating known practices without knowing the processes involved in their design. Therefore, this paper seeks to identify the algorithmic steps implemented in the derivation of contemporary façade. The design algorithms of pattern-based building envelopes are classified into generative algorithms of the basic pattern and elements, and transformation algorithms. An experimentation method was applied using Grasshopper for Rhino to simulate the formation of nine contemporary pattern-based envelopes. The finding reveals that several approaches are implemented such as elements are extruded from the basic pattern or separated from it. The envelope pattern may result from repeting the elements, or the envelope pattern may be devoid of elements. Modification techniques can manipulate the basic pattern, the elements, or both patterns and elements. They act on the patterns and elements simultaneously in the same way, or separately using different ways. [ABSTRACT FROM AUTHOR]

As a climate-responsive building, the building integrated heat pipes (BIHP) can greatly improve the indoor thermal environment during the local heating season, utilizing the thermal diode characteristic and ultrahigh equivalent thermal conductivity of the L-shaped flat gravity heat pipe. The thermophysical properties of the internal envelope greatly influence the heating effect, and the utilization potentiality of BIHP varies in locations with diverse climate resources. In this paper, the utilization effects of BIHP at 61 locations in severe cold and cold regions of China are investigated. Improved backtracking search and particle swarm optimization are used to obtain the optimal heating effect and the corresponding thermophysical properties of the internal envelope at zero-carbon heating locations and non-zero-carbon heating locations, respectively. The relationship between the improvement degree of thermal discomfort and the solar radiation over temperature difference is studied, and the utilization potentiality map and zoning of BIHP are obtained. This study is of great significance for promoting the application of climate-responsive BIHP to effectively and efficiently utilize solar energy to reach zero-carbon heating. • Proposes improved backtracking search for zero-carbon heating solution set of BIHP. • Obtains zero-carbon heating solution set of interior envelope thermal properties. • Obtains relationship between RRTD and IDTD for heating effect pre-evaluation. • Obtains application potential map of BIHP in severe cold and cold regions of China. • Proposes three zones of application effect of BIHP based on RRTD. [ABSTRACT FROM AUTHOR]

Recent development of powder-bed additive manufacturing promises to enable the production of architectural structures that combine high resolution and articulation with economies of scale. These capabilities can potentially be used for functionally graded metamaterials as part of the building envelope and structure, paving the way for new functionalities and performances. However, designing such multifunctional structures requires new design and modelling strategies to control, understand, and generate complex geometries and their transcalar interdependencies. The work presented here demonstrates a modeling framework that can unite multiple generative and organizational algorithms to create a unified, 3D printable building element that integrates a range of functional requirements. Our methods are based on an understanding of stigmergic principles for self-organization and developed to allow for a wide range of application scenarios and design intents. The framework is structured around a composite modeling environment based on a combination of volumetric modeling and particle-spring systems, and is developed to negotiate the large scalar range necessary for such applications. We present here a prototype demonstrator designed using this framework: Meristem Wall, a functionally integrated building envelope fabricated through a combination of powder bed 3D printing and CNC knitting. [ABSTRACT FROM AUTHOR]

Operational building energy consumption accounts for 55% of global energy consumption. Most of this is attributed to residential buildings, as they make up the largest building type when compared to the total building stock worldwide. As the building envelope is a major contributor to building energy performance, especially the external walls, its optimisation is therefore imperative to reduce energy consumption and carbon emissions. This study set out to assess the effects of waste material additions to external walls and their effect on building energy performance. This research aimed to critically investigate the effect of rice husk ash (RHA) masonry blocks on building energy performance when compared to conventional masonry blocks in tropical climates. A mix of methods, including experimental investigation and simulation studies, were employed for this study. Three variations of RHA block samples were created for this investigation: RHA 5%, RHA 10%, and RHA 15%. Using prototype buildings from the study context, the building simulation results helped quantify the impact on building energy performance from the reuse of rice waste. The largest improvement to the building fabric was recorded with the RHA15% blocks, which resulted in a 9.9% and 11.3% reduction in solar heat gains through the external walls for the selected bungalow and duplex/storey building, respectively. This resulted in a 6.55% and 4.2% reduction in cooling loads and a 4.1% and 2.8% reduction in carbon emissions, respectively, for the bungalow and duplex/storey building. The findings of this research will prove valuable to householders, researchers, architects, and policymakers in their decision-making processes. The findings will also be useful in introducing new methods that can be adopted for similar studies, bridging the knowledge gap while promoting a circular economy through the reuse of landfilled waste. [ABSTRACT FROM AUTHOR]

Wood processing residues provide a possibility to produce thermal insulation material with low environmental impact. This paper deals with the hygrothermal performance of timber-framed exterior walls with wood shavings as insulation material. The presented study consisted of field measurements of five exterior wall structures with two different types of wood shavings insulation and three reference walls. The study was performed in cold Nordic climate, where hygrothermal conditions at outer parts of a wall structure are critical. Untreated wood shavings and wood shavings coated with pulverized clay were compared as insulation materials. Different wind barriers as well as a water vapour barrier and sheathing acting as vapour retarder were also used. Results indicated no suitable conditions for mould growth inside any wall. The thermal resistance of wind barriers as well as the clay-coating of wood shavings had positive effect on the hygrothermal performance of the test walls. Wood shavings proved to be suitable insulation materials for well-insulated structures from the hygrothermal point of view, when the overall design, construction and maintenance are carried out in a proper way. • Performance of wood shavings as thermal insulation material in timber-framed exterior walls was studied in Nordic climate. • All the studied types of wood shaving insulation performed well and are worth of further studies. • Moisture buffer capacity of insulation improves the hygrothermal performance of a well-insulated exterior wall. • No negative effects of clay-coating of wood shavings insulation were detected during the study. • Thermal resistance of wind barrier was of paramount importance regardless insulation material. [ABSTRACT FROM AUTHOR]

This paper delves into the potential impact of a changing climate on the energy performance of European buildings. Research aims to provide a comprehensive evaluation of current energy requirements focusing on the envelope, considering existing regulations in national policies. Energy simulations are conducted at 94 locations across the European Union to cover the climatic variability and Koppen climate classification. The research analyzes future climate scenarios for the years 2030, 2050, and 2070, using three different Representative Concentration Pathways (RCP 2.6, 4.5, 8.5). According to a comprehensive analysis of heating, cooling, and overall energy performance, climate plays a significant role in buildings' energy balance. In moderately cool climate countries, the demand for air conditioning is projected to decrease in the years ahead. Conversely, in countries with a warm climate, there is a projected increase in the overall energy demand. Consequently, a revision of current energy regulations should be a priority. Providing insights into the relation between building design, energy efficiency, and climate change, the research identifies policy adjustments to ensure buildings can effectively respond to changing climatic conditions. A holistic and dynamic approach can support building design accounting for long-term impacts of climate change to create resilient and energy-efficient structures. • National building energy regulations of European Member States do not tackle climate change. • Over next decades, a decrease in heating demand is forecasted across all climate zones. • There is potential for a future considerable increase of cooling demand in Europe. • A reduction in total building energy demand in colder climates and an increase in warmer climates can be expected. • Revise national energy regulations, especially in warmer zones, to curb the expected rise in Europe's total energy demand. [ABSTRACT FROM AUTHOR]

Adaptive opaque facades can dynamically adapt their thermal properties according to both outdoor and indoor conditions, hence can enhance the energy efficiency of the building while maintaining high indoor environmental quality. Traditional façade thermal performance metrics such as U-value or R-value can be useful to evaluate the energy performance of buildings. However, the adaptive opaque façade systems require versatile testing protocols to characterize their thermal performance under their various operation modes. This paper provides a comprehensive review the experimental testing protocols and standards that have been reported to characterize the dynamic thermal performance of adaptive opaque façades. These testing protocols are compared to those commonly used to evaluate conventional building envelope assemblies. The outcomes of the review include a set of recommendations to develop laboratory testing set-ups, protocols, and metrics to consistently measure the dynamic thermal performance of adaptive opaque facades. • Energy demand of buildings can be reduced with adaptive opaque facades. • Adaptive Opaque facades can control dynamically heat transfer. • Few laboratory tests characterized adaptive opaque facades' thermal performance. • Reported tests have notable differences in the set-up configurations and protocols. • Recommendations are given to consistently characterize adaptive opaque facades. [ABSTRACT FROM AUTHOR]

Maintaining the airtightness of building envelopes is critical to the energy efficiency of buildings, yet leak detection remains a significant challenge, particularly during building refurbishment. This study addresses the effectiveness of the acoustic beamforming measurement method in identifying leaks in building envelopes. For this reason, an in-field study employing the acoustic beamforming measurement method was conducted. The study involved testing over 30 rooms across three different multi-story office buildings of varying ages and heterogeneous envelope structures. Numerous leaks were located in the façades, which were subsequently visually confirmed or even verified with smoke sticks. The data, captured using an acoustic camera (a microphone ring array), revealed distinct spectra that indicate the method's potential for further research. The basic functionality and the significant potential of this methodology for localizing leakages in large buildings were proven. [ABSTRACT FROM AUTHOR]

Modular construction is becoming famous for buildings because it allows a high degree of prefabrication, with individual modules easily transported and installed. Building envelope optimization is vital as it protects buildings from undesirable external environments by expressly preventing the incursion of outside elements. This research uses a systematic literature review to appraise the characteristics of modular envelope panels, focusing on hygrothermal and energy performance. A total of 265 articles were subjected to rigorous filtering and screening measures. The findings reveal notable inconsistencies in modular envelope terminologies and a lack of consistent performance measures, which present significant challenges for research and development efforts. Furthermore, the results indicate a predominant focus on hygrothermal and energy performance in existing studies, with limited attention to environmental impacts and other performance factors. Moreover, the existing literature primarily addresses modular envelope solutions in temperate climates, offering inadequate information for hot and hot–humid climate contexts. To address these gaps, this study proposes categorizing modular envelope panels into four distinct categories: active, passive, smart, and green/vegetated wall panels. These findings will benefit researchers, architects, building envelope designers, policymakers, and organizations developing building performance-related assessment ratings, standards, and codes. The study suggests adopting the categorization of modular envelope panels provided in this study and developing modular panels suitable for hot and humid climates to fill the existing knowledge gap. [ABSTRACT FROM AUTHOR]

Several studies have shown that social housing in Brazil usually fails to provide thermal comfort to its occupants. This study aimed to define energy efficiency measures for a representative social housing model to, together with local production of renewable energy, achieve the nearly zero-energy target. The thermal performance and energy efficiency of the representative model were evaluated using computer simulation, considering the southern Brazilian climatic context. An analysis of the economic feasibility of energy efficiency measures was also carried out. The results showed that the nearly zero-energy model with energy efficiency measures on the envelope (EPS and gypsum board in the external walls and rock wall in the roof) and a solar water heating system reduced 13.1% of the annual primary energy consumption in comparison with the representative model. Considering the renewable energy generation in the nearly zero-energy building, the electricity consumption was 38,777.6 kWh/year lower than that in the representative model (57.0% reduction). The economic analysis of the energy efficiency measures indicated a positive net present value and a payback of nearly six years. It was concluded that using energy efficiency measures and an on-site renewable made it possible to reach the nearly zero-energy target in a representative social housing model. [ABSTRACT FROM AUTHOR]

Buildings consume about 40% of global energy. It is essential to use various measures to reduce the energy consumption of the buildings as much as possible. This research investigates the impact of using a new combination of thermochromic (TC) materials in the building envelope of educational buildings. A case study building at Razi University was selected, and a 3D model was created in DesignBuilder software. Firstly, TC coating for external walls was entered into the base model, and several simulations were performed to find the effect of this coating on the energy consumption of the building. Then, a low-emissivity thermochromic (LETC) window was defined using energy management system (EMS) scripting and was entered into the base model. Finally, these two measures were combined, and the cumulative effect of using both TC coating on the external walls and LETC window was identified. Results indicated that the simultaneous application of these two measures reduced the heating demand of the building more in Tabriz, with the least cooling degree days (CDD). Also, simulation results revealed that the simultaneous use of these measures decreased the cooling demand of the building more in Bandar Abbas, with the highest CDD. Using TC coating on the external walls and LETC windows together reduced the energy consumption of the building more in Bandar Abbas. Consequently, integrating these measures can reduce the heating demand of educational buildings more in heating-dominated climates. Also, the simultaneous use of these measures can reduce cooling demand more in cooling-dominated climates. [ABSTRACT FROM AUTHOR]

The construction industry plays a significant role in shaping our environment and economy. However, it also substantially impacts the environment, including the depletion of natural resources, increased energy consumption, and waste generation. The green building trend has recently gained significant attention in recent years to mitigate the negative impacts of the building industry, focusing on sustainable materials and practices. One of the primary materials used in this field is clay brick, which leads to soil depletion over time. In this context, this study explores the potential of sawdust waste as a partial replacement for clay in brick production, aiming to reduce the depletion of natural resources while enhancing the properties and performance of the produced bricks. The study consists of two main phases: experimental and simulation. In the experimental phase, clay brick samples were produced by adding sawdust at different ratios (1%, 2%, 4%, 8%, and 10% of the raw weight), and various physical and mechanical properties of the produced samples were tested to ensure their suitability for construction use. Also, the thermal properties of the proposed brick were measured to investigate the effect of sawdust addition on brick thermal insulation. Consequently, thermal conductivity and specific heat were measured. In the simulation phase, DesignBuilder software (version 7.0.2) was used to investigate the impact of the proposed material on building envelope's performance and heat gain reduction. All experimental and simulation results were compared with the traditional clay brick measurements, which reveal a significant improvement in brick properties and performance with an increase in comprehensive strength of up to 192.3% and a reduction in energy consumption reaching 11.27%. The study results showed significant improvement in the properties and performance of the produced bricks, indicating the potential of using sawdust waste as a sustainable material for green buildings. [ABSTRACT FROM AUTHOR]

Recognizing the significance of solar energy as a vital renewable energy source in building envelope design is becoming more and more important and needs urgent attention. Exploring solar adaptation strategies found in plants offers a wide range of effective design possibilities that can substantially improve building performance. Thus, integrating solar technologies with biomimetic solar adaptive solutions could establish a suitable combination towards a sustainable design. In this context, this study follows an interdisciplinary approach to provide a link between plants' solar adaptation strategies, building integrated photovoltaics and building envelope design. To do so, a framework has been presented using data synthesis and classification to support the potential integration of three photovoltaic (PV) technologies with plant-inspired building envelope design, facilitating a harmonizing approach between biomimetic design and the application of photovoltaic technologies in buildings. [ABSTRACT FROM AUTHOR]

Bio-composite insulation materials play a crucial role in reducing the environmental impact of buildings. This paper numerically investigates the eco-friendly application of mycelium in south-facing walls in Marrakech, Morocco, using 2D CFD simulations. In this context, the thermal efficiency of bio-sourced insulating materials was assessed and compared to that of conventional insulating materials. The study basically aims at the time lag and the decrement factor analysis to evaluate the dynamic thermal performance of a multilayer wall insulated with mycelium. A life cycle cost analysis (LCCA) is performed to establish the optimal thickness of the mycelium insulation, which was turned out to be 0.08 m. This optimization leads to a substantial improvement in energy efficiency, resulting in energy savings increasing by 87.4 % in winter and 55.9 % in summer. Besides, during the last 72 h of the simulation, the indoor surface temperature drops by approximately 4 °C on summer days and raises by approximately 1 °C on winter days. The thickness of mycelium insulation was found to have a significant impact on energy savings, increasing them from 56 % to 93 %, and representing nearly a 1.7-fold improvement. The study has also targeted annual CO2 emissions to reveal a potential reduction of around 72 % using optimal mycelium composite insulation. Finally, a comparative analysis with the guidelines of Moroccan thermal regulations was achieved. The obtained findings exhibit that the examined configuration excels in terms of thermal performance, economic feasibility, and environmental benefits.

Envelope air leakage is a large contributor of energy loss in modern high-performance construction. Building enclosure designers along with the building science community are emphasizing the importance of incorporating air barrier products in the envelope design. Furthermore, regulators are reassessing the allowable air leakage limits prescribed in local codes, to reduce unintentional infiltration. Although voluntary, Passive House building standards inform methods and targets for achieving minimal air leakage values to meet certification. Commercial air barrier products often satisfy the airtightness requirements during and immediately following construction. However, seismic events could potentially damage the air barrier product and compromise the envelope’s air tightness. This paper presents the findings of an experimental program conducted to test commercially available air barrier products under in plane cyclic loading. A cyclic loading profile was designed to simulate a seismic event. Selected air barrier products were adhered to small-scale sheathing panels and tested after curing. Multiple combinations of sheathing board material and air barrier tapes were tested. The tested sample groups represent the most common air barrier systems used in the industry, incorporating 3 M Construction Seaming Tape, Siga Wigluv 60, Prosoco R-Guard Joint and Seam Filler, and Zip System Tape. The failure load and failure displacement were recorded for each test, along with the corresponding failure mode. The results of the experimental program suggest that 0.5-inches [1.27 cm] of in plane vertical displacement could completely compromise the air barrier layer due to the delamination or tear of the air barrier sealant.

Pattern-based building envelope is a modern style of contemporary facades. Architects may rely on imitating known practices without knowing the processes involved in their design. Therefore, this paper seeks to identify the algorithmic steps implemented in the derivation of contemporary façade. The design algorithms of pattern-based building envelopes are classified into generative algorithms of the basic pattern and elements, and transformation algorithms. An experimentation method was applied using Grasshopper for Rhino to simulate the formation of nine contemporary pattern-based envelopes. The finding reveals that several approaches are implemented such as elements are extruded from the basic pattern or separated from it. The envelope pattern may result from repeting the elements, or the envelope pattern may be devoid of elements. Modification techniques can manipulate the basic pattern, the elements, or both patterns and elements. They act on the patterns and elements simultaneously in the same way, or separately using different ways.

A large proportion of building energy consumption in tropical countries like Thailand primarily comes from air conditioning systems used to maintain the comfort level of building occupants. This paper aims to evaluate the performance of an alternative cooling system based on the evaporative principle in terms of thermal characteristics and energy consumption. A simulation model using computational fluid dynamics (CFD) software ANSYS version 16.0 and an actual experimental setup at the laboratory level were built to verify the results of the proposed cooling system. Additionally, factors that influence performance, such as components of the building envelope and the building’s orientation, are considered. This research aims to demonstrate the impact of building envelope material and building characteristics on the energy usage in air conditioning systems and to propose an energy-efficient cooling system. The results demonstrate that the proposed cooling system can reduce the temperature inside the building. However, the characteristics of the building also affect the energy performance. Thus, the proposed cooling system, in combination with an efficient envelope material, can achieve energy savings of around 35–43%. Therefore, a combination of the proposed cooling system and optimal building design can ensure comfort for building occupants while saving energy.

The need to design buildings in compliance with the Paris Agreement goal requirements is urgent, and architects and engineers need to consider energy use and operational and embodied carbon requirements in doing so. Building envelopes will be an important element in the next generation of high-performance buildings and there have been significant advancements in recent years to develop building envelopes that help mitigate the building carbon emissions through energy-conserving low-embodied carbon or carbon-sequestering solutions. The key objective of this article is to present an overview of the state-of-the-art in the field of energy-efficient low-carbon buildings with a focus on envelope systems. This article provides a survey of the literature on energy use and carbon emissions of the United States building stock, presents recent advancements in energy-conserving building envelopes, and highlights reuse–reduce–sequester strategies that mitigate the embodied carbon of buildings. As materials are critical in reducing the energy consumption and carbon emissions of buildings, this paper also presents developments on diverse materials and building envelope solutions that have been effective in creating high-performance buildings, from insulation materials to phase-change materials and aerogels. Finally, the characteristics of a selected number of progressive net-zero-energy guidelines such as Passive House Institute (PHI) standards, Passive House Institute US (Phius) standards, the PowerHouse standard, and the BENG standard are discussed. The findings of this work highlight the increased focus on the design, construction, and engineering strategies that aim to mitigate the carbon emissions of buildings based on a holistic whole-life carbon mitigation approach.

Prefabricated temporary buildings are a promising solution for post-disaster scenarios for their modularity, sustainability and transportation advantages. However, their low thermal mass building envelope shows a fast response to heat flux excitations. This leads to the risk of not meeting the occupant comfort and HVAC energy-saving requirements. The literature shows different measures implementable in opaque surfaces, like vacuum insulation panels (VIPs), phase change materials (PCMs) and switchable coatings, and in transparent surfaces (switchable glazing) to mitigate thermal issues, like overheating, while preserving the limited available internal space. This paper investigates the energy and overheating performance of the mentioned interventions by using building performance simulation tools to assess their effectiveness. The optimization also looks at the transportation flexibility of each intervention to better support the decision maker for manufacturing innovative temporary units. The most energy-efficient measures turn to be VIPs as a better energy solution for winter and PCMs as a better thermal comfort solution for summer.

This paper details the comprehensive activities conducted in a laboratory setting to assess the structural health monitoring (SHM) of prefabricated building envelopes. Integrating sensors into building components like curtain wall facades poses challenges but offers opportunities for monitoring structural health, requiring compliance with regulatory standards. The research investigates the possibility of defining a kit of conventional and multi-parameter sensors integrated within the building envelope to monitor its behavior during the performance test conducted. The kit of sensors also includes Fiber Optic Sensors for effectively monitoring building envelope behavior and structural integrity. In this context, the European project InComEss (H2020-GA862597) aims to define a stand-alone solution for SHM using Piezoelectric Energy Harvesting Systems (PE-EHS) for façade monitoring through FBG/FOS system. After analyzing the main façade structural stress, a series of FBGs, accelerometers, and force washers were integrated within a 1:1 scale façade prototype and tested in a laboratory following the test sequence parameters required by the curtain wall standard EN 13830. The data collected were analyzed with the aim of monitoring the façade behavior before and after the tests. The results show that the façade’s performance passed the assessing test criteria without reporting any damages. In addition, the outcomes demonstrated the effectiveness of the defined kit of multi-parameter sensors for the building envelope’s SHM.

In the cold regions of China, the existing rural houses are widely distributed and in large numbers. There are widespread problems such as low thermal performance of building envelopes, high building energy consumption, and poor indoor thermal environments. Reducing the energy consumption of building heating by reforming the envelope structure can reduce the environmental pollution caused by heating. In this paper, the existing rural houses in Tongchuan City, Shaanxi Province are taken as the research object, and EnergyPlus software is used to calculate building heating energy consumption, and the schemes are compared and selected via the entropy value method. Based on a comprehensive benefit evaluation, the best scheme for the renovation of building envelopes of rural houses in Tongchuan City is put forward. The research results show that the energy saving rate of buildings can reach more than 50% after renovation. In the evaluation of energy saving, incremental cost, return on investment, carbon emission reduction and unguaranteed hours, the weights are 0.1915, 0.2104, 0.2312, 1755, and 0.187, respectively. The best renovation scheme for rural housing is as follows: the thickness of the XPS board is 90 mm for exterior wall insulation; the thickness of the XPS board is 80 mm for roof insulation; the window-to-wall ratio of additional sunspace is 0.6; and the type of exterior windows is a broken-bridge hollow aluminum window of 6 + 12A + 6 (mm).