Building Exterior Research Articles

Dynamic thermal performance of prefabricated temporary exterior wall using cooling water in the cooling season

The acceleration of urbanization has led to a continuous increase in various types of buildings. In the hot season, cooling systems cool buildings and improve their comfort. However, traditional cooling methods require more energy consumption and greenhouse gas emissions. This paper designs a prefabricated building exterior wall with embedded pipes based on water cooling system reduces the output of traditional cooling way in building cooling. The innovation of this research is using the embedded pipe to improve the thermal properties of exterior walls, bonging the embedded pipe and exterior wall structure together. The results show that the embedded prefabricated building exterior walls are designed to control the indoor wall temperature to around 28 ℃ in summer. And the temperature on the surface of the inner liner cavity is always above 25.5 ℃. The overall trend shows a decrease followed by an increase. At noon, the surface temperature on the cavity side of the inner lining plate is the lowest, about 25.8 ℃. The larger the indoor and outdoor temperature difference, the better the cooling effect of the structure on the building. This study's application can help reduce energy consumption and carbon emissions effectively.

A state-of-the-art review of novel aerogel insulation materials for building exterior walls

ABSTRACT The unique network-like framework and nanopore structure of aerogel endow it with excellent thermal insulation performance. The thermal conductivity is as low as 0.012 W/(m·K), far lower than 0.035-0.040 W/(m·K) of traditional thermal insulation materials. Research and industrialization of nanoaerogels as building insulation have gained increasing attention in recent years. This paper discusses the application status, existing challenges, and solutions in the field of building external wall energy conservation and insulation based on nanoaerogel materials. First, it reviews the research progress of nanoaerogels and the development status of traditional building exterior wall insulation materials. The external wall using nano aerogel can reduce the heat loss by about 40%. Second, it focuses on the characteristics and research status of several types of aerogel thermal insulation products for buildings. Some products show that the energy efficiency has been improved to 50% in practical applications. Finally, it analyzes existing challenges of nanoaerogels in the application of building external wall thermal insulation and summarizes the development direction of industrialization research. Building external wall thermal insulation and the application and development of aerogels in the field of building energy conservation are facilitated by this analysis.

Optimum Geometry of Double-skin Self-Shading Facade of Classrooms with the Aim of Creating Energy Saving and Visual Comfort in Isfahan Province, Iran

The significant energy consumption in educational spaces worldwide and its environmental impact greatly influence the quality of space, learning levels, and student comfort. Despite offering free school energy costs, developing countries like Iran have not established specific design principles to ensure student comfort. Additionally, the poor design of school building exteriors, such as the common installation of large, unshaded windows in Iranian schools, causes glare issues. The primary objective of this study is to control direct sunlight and increase shading, thereby reducing its impact on energy consumption and enhancing visual comfort. This paper proposes a novel solution that combines a self-shading facade with a double-skin facade for classroom spaces. The study variables, involving the modification of the geometry of the double-skin self-shading facade via DesignBuilder software and the Daysim plugin, were compared to a simple double-layer facade. Based on the results, the optimal scenario for the self-shading double-skin façade with the specifications of a triangular pyramid module shape, ridge position fold 3/2 the module height, cavity depth 7.0, and number of module 2×2 exhibited 40% lower cooling load, 25% lower heating load, and 95% lower lighting load than a simple double-skin facade. At the same time, all scenarios of the new solution provided better visual comfort and daylighting criteria compared to the simple double-skin facade. The modularity and use of indigenous brick materials in the double-skin self-shading facade design reduce construction costs.

The Influence of Building Surroundings and Glass Cover in Bird Collisions

The characteristics of building surroundings can influence the number of bird deaths caused by collisions with glass structures. Thus, this study investigated whether the number of trees, the distance to the nearest tree, the number of fruit trees, and the glass area influenced the number of bird collisions on a university campus in Brazil from March 2017 (breeding and non-breeding seasons) to January 2018 (breeding season). Twenty-four birds died due to collisions with the windows in the one-year sampling. Among the factors evaluated, the number of trees and the area of the glass predicted the number of deaths from collisions. The greater the number of trees and the glass area, the greater the number of bird collisions. This suggests that the more vegetation there is near windows, the more birds are attracted, and the less visible the glass barrier becomes, possibly due to the appearance of trees in reflections or scenes viewed through the glass, making it difficult for birds to distinguish the real landscape from the reflected environment. If large expanses of glass are placed on buildings near vegetation, including trees, more bird collisions will occur. Thus, to reduce bird collisions, building designs should reduce the amount of glass used on building exteriors near vegetation and ensure the glass is treated with visual markers.

Local-Global Feature Adaptive Fusion Network for Building Crack Detection.

Cracks represent one of the most common types of damage in building structures and it is crucial to detect cracks in a timely manner to maintain the safety of the buildings. In general, tiny cracks require focusing on local detail information while complex long cracks and cracks similar to the background require more global features for detection. Therefore, it is necessary for crack detection to effectively integrate local and global information. Focusing on this, a local-global feature adaptive fusion network (LGFAF-Net) is proposed. Specifically, we introduce the VMamba encoder as the global feature extraction branch to capture global long-range dependencies. To enhance the ability of the network to acquire detailed information, the residual network is added as another local feature extraction branch, forming a dual-encoding network to enhance the performance of crack detection. In addition, a multi-feature adaptive fusion (MFAF) module is proposed to integrate local and global features from different branches and facilitate representative feature learning. Furthermore, we propose a building exterior wall crack dataset (BEWC) captured by unmanned aerial vehicles (UAVs) to evaluate the performance of the proposed method used to identify wall cracks. Other widely used public crack datasets are also utilized to verify the generalization of the method. Extensive experiments performed on three crack datasets demonstrate the effectiveness and superiority of the proposed method.

Development of Wall Hammering Inspection Systems Using Two-Wheeled Multi-Copters

In this study, we investigated inspection robots that can safely, accurately, and quickly perform hammer sound inspections on tile exterior walls and present new wall hammering inspection systems using two-wheeled multi-copters. Our results yielded the following five advantages. First, the proposed multi-copter can use its wheels not only to move freely on the walls of buildings but also to overcome obstacles on the walls. Therefore, almost any tile wall surface can be inspected for hammering sound. Second, the multi-copter was equipped with both hammer-shaped rods to hit the tile exterior wall and microphones to collect the hammer sound of the tile, while moving quickly on the wall surface. Third, the wall hammering inspection systems can be used safely with a work assistance mechanism using a wire even in densely populated areas, such as urban areas, because the multi-copter has high wind resistance against crosswinds by both pushing against the wall and operating by the wire. Fourth, we presented some automatic control systems that make the multi-copter operation easy during hammering inspections and demonstrated its usefulness through experiments. Fifth, we proposed useful methods for detecting floating tiles based on the hammering results, conducted some outdoor flight experiments on building exterior walls, and demonstrated that floating tiles can be determined with high accuracy.

A comparative study on the optical performance of retro-reflective coatings before and after the aging process

Retro-reflective (RR) materials are largely included among the strategies to mitigate Urban Heat Island (UHI) phenomenon in the urban spaces thanks to their optical directional properties. As materials potentially used in the building exterior envelope, RR materials are subjected to outdoor aging and soiling processes, which could alter their optical behaviour. In this perspective, the investigation focuses on the characterization of the optical performance of several types of RR plaster coatings after outdoor aging and soiling processes. The RR plaster coatings were previously developed and studied, before undergoing the outdoor exposure. The RR samples were developed covering the support with a reflective white paint and glass beads. Five different microsphere diameter ranges and three different microsphere superficial density ranges have been employed. In this paper, the RR plaster coatings were tested in terms of optical properties after outdoor aging and soiling and results were compared with data of the same plaster coatings pre-aging. Generally, all RR aged samples show a lower solar reflectance in the Vis region with respect to the pre-aging conditions. The RR behaviour is qualitatively maintained after aging and soiling. The RR sample made of glass beads of 200–300 μm diameter range could represent the best solution both in pre- and post-conditions and both in terms of solar reflectance and retro-reflective behaviour, regardless of the density of microspheres used.

Horizontal Heat Flux Spread in an Inner Corner of Buildings

This study investigates fire separation distances as essential means of passive fire protection in building design. The focus is on the inner corner configuration of building exterior walls, which represents the worst-case scenario for façade fire spread outside of a building. The inner-corner configuration appears to increase the intensity of the radiative heat flux due to reflection and reradiation of heat. Comprehensive approaches for determining fire separation distances around the various façade geometries can be found, but none of them is focused on detailed descriptions of the unprotected area in an inner corner. A medium-scale scenario was chosen and was experimentally validated with a radiant panel for a better understanding of heat flux spread. This paper compares the experiment with analytical and numerical models. The analytical model is based on the Stefan–Boltzmann law and the calculated configuration factor as per Eurocode 1. The numerical model combines radiative and convective components of the heat flux because convection is non-negligible near the heat source. Experimental data confirm the prediction based on the numerical and analytical model and show agreement. The final increase in heat flux due to the corner configuration investigated at the medium scale reaches up to 29%.

CIGS박막전지를 이용한 컬러BIPV 디자인 현황 및 사례고찰

This study examines the development status of domestic color solar cells and eight domestic and international application sites to overcome the limitations of early-stage BIPV modules that focus only on expanding and distributing power generation and do not meet various building regulations and rules, and to solve somewhat neglected building and cityscape problems. In addition, it analyzes its characteristics to improve the misconceptions and limitations of existing BIPV and to contribute to improving domestic architectural application conditions and future energy policies by reborn as a true product with the function of building exterior materials. In this study, it was found through domestic and international cases that the common feature of BIPV installation cases using CIGS thin-film cells is that BIPV is installed on the entire exterior of a building to meet power generation while pursuing consistency in the design of the exterior, and that CIGS modules satisfy most of the architectural functions that BIPV should have. In addition, although the inevitable efficiency reduction occurs when PV modules have color, it was confirmed that this is a part that must be tolerated to some extent in the comprehensive and combined sense that the ultimate goal of BIPV is to realize sustainable architecture by replacing existing building materials while generating energy. However, there are still many shortcomings in satisfying the color and size required in architecture, and the color that takes into account regional characteristics, so further technological development and advancement are needed.

Large-scale prediction of solar irradiation, shading impacts, and energy generation on building Façade through urban morphological indicators: A machine learning approach

Incorporating Building-integrated Photovoltaics (BIPVs) into urban environments offers a sustainable approach by transforming building exteriors into renewable energy sources, especially by utilizing the extensive vertical surfaces in cities. While individual building applications have been extensively studied, there is a lack of research on BIPV potential at the urban scale due to the complexity of urban fabrics. Therefore, this study presents a novel method for predicting large-scale solar irradiation and energy generation on building surfaces using urban morphological indicators through machine learning models. Using an Australian city as a case study, a hierarchical two-level machine learning model is developed to predict the solar potential for building façade PV systems. The model incorporates 13 urban morphological predictors to determine average shading height and unshaded solar irradiance. By combining these predictions with wall datasets and different façade BIPV efficiencies, the proposed method predicts unshaded electricity generation. The results showcase high efficiency and accuracy in the prediction of the shading height, solar irradiance, and electricity generation. This innovative approach aids urban planners in considering large-scale surface BIPVs into urban development.

Evaluate the Dynamic response of Buildings to Seismic Forces, Considering the Interaction between human Occupants and Structural vibrations

Damage to buildings and other structures may occur when dynamic loads, caused by earthquake vibrations, drive the ground and everything related to it to shake in a complicated way. Civil engineers are always thinking of new methods to deal with this inevitable problem. Humans put stress on a variety of buildings, including floors, footbridges, stadiums, and more. Modern material and manufacturing technology, together with human desire for aesthetics, have made it possible to build long span structures like bridges, stadiums, floors, etc. that are sleek, lightweight, and slim. To dampen a structure's dynamic reaction, engineers use devices called (TMDs), which consist of a mass and a spring, are tuned mass dampers. When it comes to managing the structural reactions to wind and harmonic excitations, Tuned Mass Damper (TMD) is the way to go. Specifically, the shear beam and 1D lumped-mass beams are the models under consideration. The main purpose of this piece is to demonstrate how methods that use records of ambient vibration may enhance and supplement seismic risk assessments of preexisting structures. To compare the structure's reaction with and without TMD, or tuned mass damper, is mounted on the building's exterior. Using a model calculated from outside vibrations and recorded within the structure, we were able to effectively compare the building's motion to a fake ground motion. It was also determined the inter-storey drift and the stiffness of each floor.

Heat insulation and thermal insulation method of passive low energy consumption residential building exterior envelope structure based on BIM

With the improvement of economic level, a continuous rise in building energy consumption brings about serious environmental problems. Therefore, this study proposes a passive energy-consuming residential building envelope thermal insulation and heat preservation method based on building information modeling technology for building energy consumption increasing and envelope structure's performance improving. Firstly, it is a study on the passive low-energy residential building envelope's thermal insulation materials and architecture, and secondly, it is a study on the improvement of the thermal insulation and heat preservation performance of the passive low-energy residential building envelope on the foundation of building information modeling. These experimental results show that in the residential building, the indoor temperature averages around 27.8 °C, of which the highest indoor ambient temperature is found at 21 o'clock, with a temperature value of 28.4 °C, which reduces 2.1 °C when comparing with the indoor temperature under the traditional residential building. Under the exterior wall construction utilizing this technology, the temperature change of the indoor environment is smoother, which satisfies people's requirements for the indoor living environment. At the same time, the area parameters of the ventilation area of the building and the area of the envelope obtained after the analysis of BIM technology have a significant effect on the cooling of the interior. This method reduces the use of resources and lays a good foundation for the further development of building informatization, which is significant in realizing the informatization developing in construction.

Automated Geometric Quantification of Building Exterior Wall Cracks Based on Computer Vision

Automated Geometric Quantification of Building Exterior Wall Cracks Based on Computer Vision

Analysis of power generation considering design and finishing materials of thermoelectric energy harvesting blocks

A thermoelectric-generator-based energy-harvesting block capable of continuously generating electricity 24 h a day using solar radiation and waste heat from a building exterior was proposed. The energy-harvesting block consists of a thermoelectric generator and a phase change material. This study aims to investigate the amount of power generated according to various designs and types of finishing materials for energy-harvesting blocks to increase the amount of power generated by small energy-harvesting blocks. It consists of a single-layer energy-harvesting block that removes the thermal resistor, and a double-layer energy-harvesting block that enlarges the area to increase radiation and convection. Four types of energy harvesting blocks applied with black coating were manufactured to increase the insolation absorption rate, and the temperature and open circuit voltage were measured. Among the four types of energy-harvesting blocks, the black-coated double-layer energy-harvesting block produced the maximum power generation of 0.0601 Wh/day. The black coating has a significant influence on the inflow of solar radiation and the amount of power generated, and the double-layer energy-harvesting block is a suitable design to maximize the amount of power generated.

Impacts of Dampness on Structural Stability of Public Secondary School Buildings in Adamawa State, Nigeria

This research assessed the impact of dampness on the structural stability of public secondary school buildings in Adamawa state. Dampness as it were is the infiltration of water through the structural elements (interior and exterior) of an edifice, wetness of structural elements through moisture rise by capillary, or extreme quantity of moisture contained in building materials or the building components (Agyekum, Ayakwa, Koranteng & Adinyira, 2013a; Wilkowska, 2017). A percentage of building structures that deteriorate during wetness, dampness, or excessive moisture movements are perceived, visible, or measurable (Soldatova, Sansone, Stephens & Shah, 2011). A building is described as being affected by dampness when there is moisture that is not wanted to a certain degree in the building than its water- retaining capability such that finishes and structural members are stained or discoloured and certain secondary elements are either upturned or lifted (Ishak, Che Ani, Akashah &Kayan, 2013). The primary sources of moisture in buildings according to Sulaiman and Beithou (2011) are liquid water from precipitation or plumbing leaks; water vapour from the building exterior or activities/processes within the building; liquid and vapour from the soil adjoining a building; and moisture built-in with the materials of construction or brought in with goods and people. Young (2007) and Agyekum et al. (2013), categorise the primary sources of moisture into three types: penetration dampness, condensation, and rising dampness. Specifically, it; determined the common types of dampness and common causes of dampness, it also determined the extent of the impacts of dampness and suggested suitable procedures for treating the impact of dampness. A descriptive research design was adopted for the study. Four purposes and four research questions were raised to guide the study, the population for this study is Grade A public secondary schools in Adamawa State. Three sampling techniques were employed in this study, these are stratified sampling, purposive sampling, and simple random sampling. A checklist and a structured questionnaire were developed.

Evaluating human perception of building exteriors using street view imagery

Building appearances profoundly shape the urban visual landscape, influencing city images and the quality of urban life. Traditional methods for evaluating the perceptual and aesthetic qualities of building facades are often limited in scope. Despite recent studies that have sought to understand human perception of urban streetscapes, our grasp of how individuals perceive building exteriors on a broader scale and the subsequent impact on holistic street experiences, remains largely unexplored. In this study, we integrate a traditional survey-based evaluation framework with machine learning techniques to analyse human perception of over 250,000 building images from Singapore, San Francisco, and Amsterdam. Specifically, deep learning models trained on crowdsourced ratings of 1200 building images across six perceptual attributes — complex, original, ordered, pleasing, boring, and style — achieve over 72% accuracy. This novel approach enables adaptive and comparative analyses of building appearances across regions, revealing spatial patterns in the perception of architectural exteriors and their relationships with functions, age, and location. Moreover, by applying propensity score matching to match images based on their features, we mark one of the first efforts to investigate the perceptual impacts of buildings on streetscape perceptions. The results show that streetscapes with higher levels of complex, pleasing, and historical ambience from buildings elicit more positive perceptions, whereas modern and monotonous exteriors often evoke holistic feelings of being “boring” and “depressing”. These findings offer architects and city planners valuable insights into public sentiment towards city-level building exteriors and their influence on urban identity and perception.

Automatic detection and classification process for concrete defects in deteriorating buildings based on image data

ABSTRACT Defects in buildings accelerate the deterioration of building conditions and threaten the structural safety of buildings. Building condition assessments are essential to identify and assess building defects. However, with the vast number of buildings, individual inspections are nearly impossible, highlighting the need for innovative solutions. Therefore, this study presented a safety inspection process that automatically detects and classifies defects using image data that can be easily acquired at a low cost and confirms the location of defects through 3D modeling. A CNN model is developed to detect defects in images of aging buildings, and the proposed process is validated through a case study to demonstrate its effectiveness. The case study focused on the effectiveness and convenience improvement of the proposed process compared to the existing methods of inspecting the exterior of buildings. The effectiveness of the proposed process was reviewed through the case study, and it was confirmed that more efficient safety inspections could be supported using only image data compared to the existing methods. In particular, the safety inspection process of this study is expected to be applied in practical use within a short period since it is an easily utilizable method for inspectors.

Assessment of the Renovation Need, Material Authenticity, and the Cultural and Environmental Value of Historic Apartment Building Neighbourhoods

Preserving the built heritage, maintaining the original exteriors of historic apartment buildings, and achieving today’s living standards and ambitious environmental objectives require a multidisciplinary approach encompassing cultural, economic, legal, social, environmental and historical factors. This study aims to assess the need for renovation and the cultural and environmental value of historic apartment buildings. Architects, conservators and civil engineers have been involved to evaluate the authenticity of materials and forms, their technical condition and suitability to the historic urban milieu across 19 building components. Our findings reveal significant replacement activities in various elements such as roof coverings, roof eaves, façades, stairwell windows, stairwells, exterior doors, and window and frame distribution, with a particular focus on materials rather than geometry. Notably, there is often a lack of original materials of the windows. When comparing materials and geometries, we observed a higher frequency of material replacement. While the immediate need for intervention may not be urgent, many historic apartment buildings are at risk of imminent material deterioration, necessitating timely renovation. The deep renovation approach, which extends the service life, enhances energy efficiency and indoor climate and restores the exterior aesthetics, offers a threefold benefit. However, aligning the current reconstruction requirements with the preservation of milieu values may remain ambiguous, leading homeowners to resist or overlook these obligations. Consequently, a culture of step-by-step (staged) renovation emerges, contributing to an eclectic appearance of the historically valuable area and promoting the use of inappropriate materials. In conclusion, this research emphasizes the importance of a holistic approach to building renovation, which yields architecturally superior and technically sustainable outcomes. The current study underscores the necessity for a shift in the authorized heritage discourse in Estonia. Rather than primarily imposing restrictive measures on construction and renovation projects, the focus should pivot towards effective communication of historical values. It is crucial to provide support and guidance (not restrictions) to building owners, designers and builders in this regard.

Thermal performance of a novel Trombe wall enhanced by a solar energy focusing approach

The Trombe wall is a passive solar building exterior wall system proposed by Professor Felix Trombe in France, which can collect solar energy to heat buildings without additional energy consumption, making it a focal point of research in building energy conservation. However, its effectiveness is constrained by the low density of solar radiation in winter and the potential for overheating in summer. This study introduces a novel Trombe wall designed to address these issues through a focused strategy, enabling automatic transition between heating during winter and shading during summer. The thermal performance parameters of the novel Trombe walls in both winter and summer seasons are examined, and their energy consumption is assessed using experimental research methodologies. Findings indicate that the novel Trombe wall facilitates greater energy savings in both winter and summer. When compared with traditional Trombe walls, the novel Trombe wall achieves a significant reduction in energy consumption, with up to 55 W/m2 in heating load during winter and 47 W/m2 in cooling load during summer. The introduction of this new system holds substantial potential for the realization of zero-energy buildings.

Flame retardancy, photostability, and thermal properties of vanillin-epoxidized soybean oil composites reinforced with walnut shell

Vanillin produced from lignin is an environmentally friendly compound having various active structures that can be crosslinked with hexanediamine and epoxidized soybean oil (ESO) to form water resistant composite. Inclusion of ammonium dihydrogen phosphate (ADP) could render the composite flame retardant, but its mechanical properties could be influenced. Therefore, walnut shell powder (WSP), as a common biomass waste, can be incorporated to improve its hardness and compressive strength. A matrix named VHEA was prepared by the condensation of vanillin, hexanediamine, ESO, and ADP. WSP was used as the skeleton for blending with VHEA to create VHEAW composite. Mechanical properties, dimensional stability, UV-resistance, thermal conductivity and flame retardancy of the composites were evaluated. The inclusion of WSP at a ratio of 1:1 to VHEA improved the compressive strength, Brinell hardness and flexural strength of the composite. Meanwhile, its water contact angle reaches 131.48 °, indicates its superior hydrophobicity. It also has high UV resistance and good flame retardancy as the LOI value is as high as 35.1 %, and its peak heat release rate is as low as 123.19 kW/m2. Its outstanding thermal insulation and flame retardancy, combined with excellent UV-resistance, render it suitable for various building components, including roofing, exterior siding, windows, and doors.