Search Results (81)

Photovoltaic double-skin façades (PV-DSFs) can block solar radiation heat, mitigate air heat transfer, facilitate ventilation cooling, and generate electricity, making them a high-performance building envelope suitable for hot southern regions in summer. The thermal performance of DSFs is relatively well understood; however, with the addition of photovoltaic glass panels, the influence of design parameters is altered due to thermoelectric coupling effects. Then, the influence of design parameters on their thermoelectric performance remains unclear, hindering their design optimization. This paper establishes a mathematical model for DSFs with MATLAB (R2023a) to analyze their thermoelectric performance and the impact of design parameters. The results indicate that the daily power generation of PV-DSFs is primarily influenced by the solar radiation on the west-facing vertical surface. The wall exterior surface gains heat via longwave radiation during the day and loses heat at night, while convective heat dissipation occurs throughout the entire day, with radiative heat flux being the dominant mechanism. The power generation of photovoltaic cells is significantly influenced by their coverage ratio, while the impact of other factors can be neglected. The temperature of the wall’s exterior surface is significantly influenced by the heat storage of the outer cladding panel, the solar absorptivity of the exterior surface, and the emissivity of the interior surface. Among these factors, the heat storage of the outer cladding panel primarily affects the attenuation and delay of peak values and temperature fluctuations on the exterior surface. Meanwhile, the solar absorptivity of the exterior surface and the emissivity of the interior surface mainly influence the peak temperature of the wall’s exterior surface, with the effect becoming more pronounced when the interior surface emissivity is lower. Full article

The relevance of this study is driven by the increasing requirements for the energy efficiency and indoor comfort of residential and public buildings, particularly in regions with extreme climatic conditions characterized by substantial daily and seasonal temperature fluctuations. Effective management of heat transfer through building envelopes has become a key factor in reducing energy consumption and improving indoor comfort. This paper presents the results of an experimental–numerical investigation of the thermal behavior of an adaptive exterior wall system with a controllable air cavity. Steady-state and transient simulations were performed for three envelope configurations: a baseline design, a design with vertical air channels, and an adaptive configuration equipped with adjustable openings. Quantitative analysis showed that during the winter period, the adaptive configuration increases the interior surface temperature by 1.5–2.3 °C compared to the baseline design, resulting in a 12–18% reduction in the specific heat flux through the wall. In the summer period, the temperature of the exterior cladding decreases by 3–5 °C relative to the baseline, which reduces heat gains by 8–14% and lowers the cooling load. Additional analysis of temperature fields demonstrated that the presence of vertical air channels has a limited effect during winter: temperature differences at the surfaces do not exceed 1 °C. A similar pattern is observed in warm periods; however, due to controlled air circulation, the adaptive configuration provides an improved thermal regime. The results confirm the effectiveness of the adaptive wall system under the climatic conditions of southern Kazakhstan, characterized by high solar radiation and large diurnal temperature variations. The practical significance of the study lies in the potential application of adaptive façades to enhance the energy efficiency of buildings during both winter and summer seasons. Full article

Façades account for approximately 15–20% of a building’s embodied carbon, making them a key target for material decarbonization. While bio-composites are increasingly explored for façade insulation, cladding systems remain dominated by carbon-intensive materials such as aluminum and fiber-reinforced polymers (FRPs). This paper presents findings from a study investigating the use of food-waste-derived bulk fillers in bio-composite materials for façade cladding applications. Several food-waste streams, including hazelnut and pistachio shells, date seeds, avocado and mango pits, tea leaves, and brewing waste, were processed into fine powders (<0.125 μm) and combined with a furan-based biobased thermoset resin to produce flat composite sheets. The samples were evaluated through mechanical testing (flexural strength, stiffness, and impact resistance), water absorption, freeze–thaw durability, and optical microscopy to assess microstructural characteristics before and after testing. The results reveal substantial performance differences between waste streams. In particular, hazelnut and pistachio shell fillers produced bio-composites suitable for façade cladding, achieving flexural strengths of 62.6 MPa and 53.6 MPa and impact strengths of 3.42 kJ/m² and 1.39 kJ/m², respectively. These findings demonstrate the potential of food-waste-based bio-composites as low-carbon façade cladding materials and highlight future opportunities for optimization of processing, supply chains, and material design. Full article

The article presents the results of a comprehensive full-scale investigation of the influence of solar radiation on the thermal behavior of the exterior envelope systems of two residential buildings of different heights—a 9-storey building in Turkestan and a 25-storey building in Shymkent. The façade systems of both buildings consist of a multilayer enclosure with a ventilated air cavity, 100 mm wide in the 9-storey building and 50 mm wide in the 25-storey building. The objective of the study was to determine the diurnal and vertical dynamics of temperature fields, analyze the thermal inertia of the materials, and assess the effect of façade geometry on heat-transfer performance. Thermographic measurements were carried out during key periods of the day (7:00, 10:00, 13:00, and 17:00), which enabled coverage of the full solar-insolation cycle. The results showed that the maximum temperatures of the external cladding reached 48–52 °C for the 9-storey building and 53–58 °C for the 25-storey building, with a vertical temperature gradient of 3–7 °C. The temperature of the interior surface varied within 28–32 °C and 29–34 °C, respectively, reflecting the influence of both solar heating and the width of the ventilation cavity on heat transfer. It was found that reducing the air-gap width intensifies natural convection and decreases the thermal inertia of the system, resulting in sharper temperature fluctuations. The study demonstrates that current design standards insufficiently account for the vertical non-uniformity of solar exposure and the aerodynamic processes within the ventilation channel. The findings can be used in the design of energy-efficient façade systems, in the refinement of regulatory methodologies, and in the development of heat-transfer models for high-rise buildings under conditions of increased solar radiation. Full article

The recycling and reuse of wood have gained importance as strategies for reducing construction waste, lowering costs, and promoting circular practices in the built environment. This study evaluates the performance of recycled wood particle/epoxy composites (WPECs) for façade applications by prototyping panels produced from granulated degraded wood bonded with epoxy resin and coated with intumescent fire-retardant paint. The panels were design to meet standards for ventilated façade applications in accordance with EN 310-93 and ASTM D1037-06a and relevant building codes for facade cladding. Three replicates of each panel type were tested under controlled laboratory conditions to assess water absorption, equilibrium moisture content, capillarity, fire resistance, and mechanical performance. Moisture measurements were performed at immersion and drying intervals of 12, 24, 36, 72, and 120 h for four WPEC types manufactured with pine, beech, oak, and olive fibers. Statistical evaluation using SPSS (one-way and two-way ANOVA) confirmed significant species effects across most parameters. Results indicated that olive and oak WPECs provided the highest dimensional stability under moisture exposure, with olive additionally demonstrating superior compressive strength (35.45 MPa) and hardness (˂10,000 N). Pine and beech WPECs exhibited intermediate bending strength (≈10 MPa) and elasticity, while oak contributed stable swelling values despite lower strength. Fire resistance tests suggested relative improvements, although further standardized evaluation is needed. Collectively, olive and oak WPECs emerged as the most promising façade materials, combining durability, mechanical strength, and sustainability. Full article

This study provides a comprehensive analysis of the fire hazards associated with Building-Integrated Photovoltaics (BIPV), using Aluminum Composite Panels (ACP) as a benchmark. Large-scale fire tests, modified from ISO 13785-1, were conducted on vertically installed BIPV modules to observe their fire behavior under conditions simulating a severe fire. The experimental process involved measuring key fire performance indicators, leading to the identification of a cascading failure mechanism. The BIPV modules demonstrated a peak Heat Release Rate (HRR) up to hi times higher (max. 898 kW) and smoke production nearly 10 times greater than the ACP baseline. The analysis reveals a distinct, multi-stage failure sequence that defines the systemic fire hazard of BIPV. Initially, a phenomenon strongly indicative of a chimney effect within the rear air cavity accelerates concealed fire spread. This rapid heating induces thermal stress, leading to extensive specimen damage termed cracking. This cracking event acts as a critical turning point, triggering a rapid release of trapped pyrolyzates and driving the fire to its peak intensity. This chain of events constitutes a unique hazard signature not observed in conventional cladding. The findings conclude that the fire risk of BIPV is a systemic issue, challenging the adequacy of component-level testing and highlighting the need for safety standards that assess the façade as a complete assembly. Full article

The increasing use of wooden cladding in multi-storey buildings raises critical fire safety concerns, especially in ventilated façade systems where the chimney effect can accelerate vertical flame spread. This study combines theoretical analysis with three full-scale fire tests to investigate key factors influencing fire propagation, including the influence of façade design details. Results show that poorly constructed lintels and jambs significantly accelerate flame entry into ventilated cavities, while wooden fire barriers—despite being combustible—can delay flame spread if properly installed. These findings inform design recommendations and underscore the need for more robust fire safety strategies in modern timber construction. Full article

Nowadays, public buildings are clad on the outside, many with stone-clad facades. Energy requirements have changed a lot in the last 20–25 years, and the latest required value of the thermal conductivity of masonry is 0.24 W/m²K. The relevant requirements, available materials, and fastening technology options have changed significantly. Our research covers a comprehensive analysis of these systems, the selection of stone cladding materials, and the suitability and use of individual stone types for facade cladding, as well as an energy examination of layered wall systems and the development of fastening elements, including the material structure of the elements and possible design and fastening methods. In the original university research, we also developed an applied technology for several product manufacturing companies in order to obtain approval for industrial application. In this article, we summarize the results of our research, the building structure and building physics issues, the necessary fastening technology design, and the main aspects of selecting stone tiles regardless of the manufacturing companies. The goal of our university research was the introduction and structural development of assembled stone facade cladding in Hungary, a development that continues to this day. The assembled stone cladding system we developed has been used to cover the facades of thousands of buildings in Hungary. Full article

Renovating existing buildings is a key strategy for achieving the EU’s climate targets, as over 75% of the current building stock is energy inefficient. This study evaluates the environmental impacts of three façade renovation scenarios for an office building at the Technical University in Zvolen (Slovakia) using a life cycle assessment (LCA) approach. The aim is to quantify and compare these impacts based on material selection and its influence on sustainable construction. The analysis focuses on key environmental indicators, including global warming potential (GWP), abiotic depletion (ADE, ADF), ozone depletion (ODP), toxicity, acidification (AP), eutrophication potential (EP), and primary energy use (PERT, PENRT). The scenarios vary in the use of insulation materials (glass wool, wood fibre, mineral wool), façade finishes (cladding vs. render), and window types (aluminium vs. wood–aluminium). Uncertainty analysis identified GWP, AP, and ODP as robust decision-making categories, while toxicity-related results showed lower reliability. To support integrated and transparent comparison, a composite environmental index (CEI) was developed, aggregating characterisation, normalisation, and mass-based results into a single score. Scenario C–2, featuring an ETICS system with mineral wool insulation and wood–aluminium windows, achieved the lowest environmental impact across all categories. In contrast, scenarios with traditional cladding and aluminium windows showed significantly higher impacts, particularly in fossil fuel use and ecotoxicity. The findings underscore the decisive role of material selection in sustainable renovation and the need for a multi-criteria, context-sensitive approach aligned with architectural, functional, and regional priorities. Full article

The increasing complexity of urban structures has significantly elevated the risk and severity of façade fires in high-rise buildings. Unlike traditional models assuming continuous fuel beds, real-world fire scenarios often involve discrete combustible materials arranged in discrete fuel matrices. This study presents a systematic investigation into the influence of lateral spacing on vertical flame propagation behavior. Laboratory-scale experiments were conducted using vertically oriented polymethyl methacrylate (PMMA) fuel arrays under nine different spacing configurations. Results reveal that lateral spacing plays a critical role in determining flame spread paths and intensities. Specifically, with a vertical spacing fixed at 8 cm, a lateral spacing of 10 mm resulted in rapid flame growth, reaching a peak flame height of approximately 96.5 cm within 450 s after ignition. In contrast, increasing the lateral spacing to 15 mm significantly slowed flame development, achieving a peak flame height of just under 90 cm at approximately 600 s. This notable transition in flame dynamics is closely associated with the critical thermal boundary layer thickness (~11.5 mm). Additionally, at 10 mm spacing, a chimney-like effect was observed, enhancing upward air entrainment and resulting in intensified combustion. These findings reveal the coupled influence of geometric configuration and heat transfer mechanisms on façade flame propagation. The insights gained provide guidance for cladding system design, suggesting that increasing lateral separation between combustible elements may be an effective strategy to limit flame spread and enhance fire safety performance in buildings. Full article

The construction sector presently consumes about 40% of global energy and generates 36% of CO₂ emissions, making facade retrofits a priority for decarbonising buildings. This review clarifies how ventilated facades (VFs), wall assemblies that interpose a ventilated air cavity between outer cladding and the insulated structure, address that challenge. First, the paper categorises VFs by structural configuration, ventilation strategy and functional control into four principal families: double-skin, rainscreen, hybrid/adaptive and active–passive systems, with further extensions such as BIPV, PCM and green-wall integrations that couple energy generation or storage with envelope performance. Heat-transfer analysis shows that the cavity interrupts conductive paths, promotes buoyancy- or wind-driven convection, and curtails radiative exchange. Key design parameters, including cavity depth, vent-area ratio, airflow velocity and surface emissivity, govern this balance, while hybrid ventilation offers the most excellent peak-load mitigation with modest energy input. A synthesis of simulation and field studies indicates that properly detailed VFs reduce envelope cooling loads by 20–55% across diverse climates and cut winter heating demand by 10–20% when vents are seasonally managed or coupled with heat-recovery devices. These thermal benefits translate into steadier interior surface temperatures, lower radiant asymmetry and fewer drafts, thereby expanding the hours occupants remain within comfort bands without mechanical conditioning. Climate-responsive guidance emerges in tropical and arid regions, favouring highly ventilated, low-absorptance cladding; temperate and continental zones gain from adaptive vents, movable insulation or PCM layers; multi-skin adaptive facades promise balanced year-round savings by re-configuring in real time. Overall, the review demonstrates that VFs constitute a versatile, passive-plus platform for low-carbon buildings, simultaneously enhancing energy efficiency, durability and indoor comfort. Future advances in smart controls, bio-based materials and integrated energy-recovery systems are poised to unlock further performance gains and accelerate the sector’s transition to net-zero. Emerging multifunctional materials such as phase-change composites, nanostructured coatings, and perovskite-integrated systems also show promise in enhancing facade adaptability and energy responsiveness. Full article

This study investigates the robustness of steel moment-resisting frames (MRFs) under column loss scenarios, both in undamaged and post-seismic conditions. In this context, robustness is defined as the ability of a damaged structure to prevent progressive collapse following an earthquake. A parametric investigation was conducted on 48 three-dimensional MRF configurations, varying key design and geometric parameters such as the number of storeys, span length, and design load combinations. Nonlinear dynamic analyses were performed using realistic ground motions and column loss scenarios defined by UFC guidelines. The effects of pre-existing seismic damage, façade claddings, and joint typologies were explicitly accounted for using validated component-based modelling approaches. The results indicate that long-span, low-rise frames are more vulnerable to collapse initiation due to higher plastic demands, while higher-rise frames benefit from load redistribution through their increased redundancy. In detail, long-span, low-rise frames experience roughly ten times higher displacement demands than their short-span counterparts, and post-seismic damage has limited influence, yielding rotational demands within 5–10% of the undamaged case. The Reserve Displacement Ductility (RDR) ranges from approximately 6.3 for low-rise, long-span frames to 21.5 for high-rise frames, highlighting the significant role of geometry in post-seismic robustness. The post-seismic damage was found to have a limited influence on the dynamic displacement and rotational demands, suggesting that the robustness of steel MRFs after a moderate earthquake is largely comparable to that of the initially undamaged structure. These findings support the development of more accurate design and retrofit provisions for seismic and multi-hazard scenarios. Full article

Aluminium composite panels (ACPs) have been used in almost every high-rise building because of their aesthetic and thermal properties. However, due to the nature of the combustibility of polymeric core materials, the fire issue is the main concern throughout the world. Several fire occurrences have been noticed in different countries. The ignition of combustible core materials used in ACP cladding is mainly responsible for spreading fire. Building-safety regulatory authorities have enforced new obligations to ban combustible ACP panels in high-rise buildings, especially in Australia and the UK. This is now considered as one of the critical components in these buildings. This study aims to comprehensively overview different types of cladding panels, core filler materials, flame-retardant mechanisms, their preparation methods, and recent developments. The PRISMA method has been used to conduct a systematic literature review. From the Scopus and Google scholar databases, a total of 180 documents have been selected using two relevant keywords through the screening process. This study reviews existing studies, covering cladding panel classifications based on standard codes, and existing ACP panels’ flammability, thermal, and mechanical properties. Following an in-depth recent literature review, the study outlines the combustibility and energy efficiency challenges and offers recommendations for future research to develop non-combustible cladding panels. Full article

In order to rationally utilize wood materials, increase wood quality, and mitigate drawbacks, research on industrial techniques for timber protection and preservation is essential on a European and global scale. When high-quality timber enters the market, it offers structures and objects that have considerable added value. This study examines the performance of thermally treated (6 h at 170 °C and 200 °C) softwood species (fir wood) when exposed outdoors and applied on wooden building structures as cladding timber, among other structures. International standards were applied for the characterization of the untreated and thermally treated wooden boards after the treatments in terms of physical, hygroscopic, and surface properties. In contrast, all the boards (of dimensions 390 × 75 × 20 mm in length, width, thickness respectively) were exposed outdoors to direct sunlight and a combination of biotic and abiotic factors for a six-month period to mainly investigate the thermal properties (heat transfer analysis/insulation properties) using a real-time test in situ, as well as to investigate their potential resistance to natural weathering (color, surface roughness, visual inspection, etc.). Heat transfer in the thermally treated wood specimens was found to be much slower than that in the untreated specimens, which, combined with lower hygroscopicity and higher dimensional stability, reveals the high potential of thermally treated wood utilization in outdoor applications, such as cladding, facades, frames, and other outdoor elements. Full article

Bell towers, due to their slender geometry and structural configuration, are among the buildings most susceptible to deterioration from weathering and seismic events. These aspects influence the structural assessment of these historic towers, which is essential for their conservation and maintenance. The “Carmine Maggiore” bell tower in Naples (Italy) has been an important and prominent landmark of the city for centuries. It is square in plan and 72 m high. Over time, it suffered extensive damage and was severely damaged by the earthquake of 1456. Reconstruction began in the first decade of the 17th century and the original design was modified, adding two stories and changing the shape of the plan to octagonal. In the centuries that followed, the structure was damaged again and further interventions were carried out, adding tie-rods and replacing damaged elements. Today, the bell tower has very elaborate façades with mouldings and decorations, so that the supporting structure appears to be covered with plaster, stucco, and stone elements. This paper describes the results of FEM analyses of the bell tower, obtained from models with different levels of complexity to evaluate the influence of stone cladding elements on the seismic behaviour. In particular, the difference in the IS safety indices, calculated as the ratio of capacity to demand, exceeds 15%, due to the mechanical consistency of the cladding elements, which contribute significantly to both stiffness and strength. Full article