Exterior Walls Of Buildings Research Articles

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.

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%.

Research on new technology of resource-saving ultra-thin stone curtain wall

Ultra thin stone curtain wall technology is a resource-saving innovation. This article explores the application of ultra-thin stone in building exterior wall decoration, including pasted curtain walls, self insulated walls, AAC walls, and decorative insulation composite board exterior wall insulation systems. This technology has advantages such as thin thickness, light weight, low cost, convenient construction, and excellent self insulation performance. The key construction points include waterproofing, rust prevention treatment, use of high standard adhesives, embedding of steel wire mesh in the plaster layer, and small mortar joint technology. The future development direction should focus on innovation in the production technology of ultra-thin stone panels and new directions for stone products.

Solid and Homogeneous Thermal Wall of Cored Lightweight Concrete Blocks Solidarized in situ

Abstract: The exterior walls of buildings play a major role in the road for a near-zero energy building. Nowadays, in Portugal, the ETICS system is the most used technology to ensure the thermal insulation of exterior walls of buildings. However, the ETICS system has low resistance to impacts and requires a self-supporting sheet of wall, among other disadvantages. Here, the concept of new technology for exterior walls of residential and commercial buildings is presented. It consists of a hybrid technology for the easy and quick execution of a single sheet wall, which may provide high thermal efficiency for buildings. This hybrid technology relates to parallelepipedshaped cored lightweight concrete blocks comprising two parallel sides separated by one or more solid connectors in which the connectors allow the filling of the block core with lightweight concrete. No bed or head joints are used to connect the blocks because the wall made of cored blocks gets solid and homogeneous when filled with lightweight concrete. When the block thickness is 30 cm and the thermal conductivity of the lightweight concrete is lower than 0.09 W/m.ºC, in Portugal, this type of exterior wall does not require the application of extra thermal insulation materials.

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

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

A study on surface temperature of different materials

Excessive buildings took over green vegetation, which aggravated the greenhouse effect. If we use vegetation as roofs and exterior walls of buildings, the areas of plants will not reduce, and even the temperature around the building will decrease. Therefore, we planned to detect the surface temperature of different materials to provide evidence for ideal materials. We detected surface temperature of different materials with an infrared temperature gun (DELIXI, DM-5002). Detected materials included turf, suffruticosa plant, and soil under them, tile or concrete, wood, water with different depths of 1cm, 5cm, 10cm. We detected different materials under different weather conditions. The surface temperature of turf was significantly decreased compared with tile or concrete, wood (p<0.05). There was no significant difference between wood and tile/concrete temperature. Compared with tile/concrete or wood, the surface temperatures of water, turf, suffruticosa plant, and soil under plant significantly decreased (p<0.05). There was no significant difference of temperature between water with different depths. There was no significant difference in temperature between turf, suffruticosa plant, and the soil under them, too. The surface temperatures of turf, suffruticosa plant, and water were significantly lower than those of tile/concrete and wood we used as raw materials of buildings. Plants can be recommended as new materials covering roofs and exterior walls to decrease temperature around buildings in summer.

Preparation and weathering properties of Ce/TiO2 anti-UV coating on heat-treated wood

Heat-treated wood is widely used as building exterior wall panels and landscape materials due to its excellent dimensional stability and durability. However, heat-treated wood is susceptible to discoloration and cracking due to ultraviolet radiation, temperature and humidity changes in the outdoor environment. In this study, Ce/TiO2 alcohol solution was prepared by sol-gel method, and the inorganic anti-ultraviolet coating was attached to the surface of wood by brush coating. Then artificial accelerated weathering test was carried out for 672 h to evaluate the weathering behavior of heat-treated wood. UV–Vis spectroscopy and macroscopic morphology analysis of the glass substrate show that the coating has good transparency and effective UV shielding ability. Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis showed that the coating successfully adhered to the wood surface and played a good anti-ultraviolet effect. After artificial weathering, the color difference values of unmodified wood, Ce modified wood, TiO2 modified wood and Ce/TiO2 modified wood were 6.04, 4.97, 3.67 and 3.29, respectively. Based on the changes of color and wood chemical composition, the Ce/TiO2 anti-ultraviolet coating can significantly improve the weathering resistance of heat-treated wood, and ultimately limit the degradation degree of surface chemical composition of heat-treated wood.

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.

Modeling the thermally adaptive performance of building exterior walls with linear temperature-dependent thermal conductivity

The concept of adapting to variable external thermal environments by varying the thermophysical properties of building envelopes has gained increased attention in recent years. This study aims to evaluate the thermally adaptive performance of exterior walls incorporating linear temperature-dependent thermal conductivity-based insulation (LTTI). A variant resistance–capacitance nodal model was developed and validated against Fluent simulations, demonstrating high accuracy and time efficiency. The study evaluates the thermally adaptive indices (i.e., the adaptive time lag, adaptive decrement factor, and thermally adaptive ratio) for LTTI-based walls with at different temperature-dependent slopes under the Beijing climate. The results show that the dynamic thermal indices follow a parabolic pattern, whereas the monthly adaptive indices exhibit a folded line pattern with the extreme value in July. The maximum value for the adaptive time lag and decrement factor reached 3.8 h and 0.003 at −1.0 mW·m−1·K−2, while minimum extreme value is observed at 1.0 mW·m−1·K−2 with −3.8 h and −0.003, respectively. Furthermore, the study determines the relationship between the heating, cooling, and overall thermally adaptive ratios and the seasonal month and the temperature-dependent slope. At a temperature-dependent slope of 1.0 mW·m−1·K−2, the heating, cooling, and overall thermally adaptive ratios were approximately 0.162, −0.045, and 0.160, respectively. These findings suggest that LTTIs with a positive slope adapt to the thermal environment in Beijing, while those with a negative slope exhibit the opposite, anti-adaptive performance. These results could provide insights into the development of energy-efficient and thermally adaptive building envelopes based on LTTI materials.

Multi-source point cloud registration for urban areas using a coarse-to-fine approach

ABSTRACT The foundational step in constructing a digital twin involves transforming the physical world into an immersive 3D virtual environment. Unmanned aerial vehicle (UAV)-based photogrammetry, mobile mapping system (MMS), and terrestrial laser scanning (TLS) serve as powerful tools for 3D reconstruction of urban environments. Given the distinctive strengths and weaknesses of each sensor, a multi-source point cloud registration technique is imperative to achieve a detailed and precisely geolocated 3D urban model. Hence, we developed coarse-to-fine approach methods, called building exterior wall-based (BEWB) and building outline-based (BOB) algorithms, to register point clouds captured by diverse sensors in urban scenes. The BEWB algorithm coarsely registers urban point clouds by extracting building exterior walls, establishing correspondence points, and effectively removing outliers within this correspondence point set. The BOB algorithm precisely registers the urban point clouds acquired from multiple sensors by leveraging building outlines and points corresponding to the ground of the point clouds. To validate the proposed algorithms, we initially registered a UAV-based photogrammetry point cloud with the MMS point cloud and subsequently registered the TLS point clouds. Comprehensive quantitative and qualitative analyzes of the results demonstrate that our algorithms outperform existing methods in achieving precise registration. By successfully registering three distinct point clouds, we generated a comprehensive urban scene point cloud characterized by enhanced precision, point density, and geolocation accuracy.

Effect of width on the fire spreading characteristics of PE metal sandwich panels under the action of double fire sources

The exterior walls of high-rise buildings typically contain substantial thermal insulation materials. Once ignited, these materials can readily induce major fire accidents. In this study, through the constructed reduced-size experimental bench to evaluate the effect of window overflow fire and upper chamber fire on the fire spreading properties of PE metal sandwich panels with different widths. The result shows that the average flame height and flame oscillation intensity increased with an increase in fire source power and sandwich panel width. Temperature curves exhibited a consistent trend under different working conditions. Dimensionless analysis of the sandwich layer temperature indicated that under specific fire source power conditions, the 60 cm sandwich panel reached the highest peak temperature and posed the greatest fire hazard. Based on the width and length of the preheating zone, a model for the rate of flame spreading was created. At a constant sample width, the accelerated spread of the upper part of the plate by the action of fire source B was more obvious. These conclusions are instructive for the study of building facade fire.

Optimizing thermal insulation in building facades: An examination of human-environment dynamics in Nanjing city, Eastern Asia

The external building walls are significant in mitigating adverse weather conditions. Current research on the thermal insulation of exterior walls often overlooks crucial factors such as human comfort, seasonal changes and environmental dynamics. This study introduced a performance evaluation approach for external walls that considered the human thermal zone, annual air temperature and solar radiation. Taking Nanjing City as a case study, the thermal insulation performance of five distinct types of building exterior walls was investigated. The findings highlight the impact of various insulated wall systems on thermal insulation. While different insulated walls exhibited significant variations in effectiveness during extreme weather episodes, these variations were minor over the course of the year. Analysis revealed a spectrum of performance for insulated exterior walls, ranging from excellent to poor: Outer Insulated Wall > Inside Insulated Wall = Sandwich Insulated Wall = Self-Insulated Wall > Mortar-Insulated Wall. The disparity in thermal insulation performance amongst four wall types was minimal, with the mortar-insulated wall demonstrating the lowest performance. The highest temperature recorded for the mortar-insulated wall surpassed 32.2°C over 68 days. This research contributes insights into the nuanced performance of various insulated walls, paving the way for decision-making in climate resilience strategies.

Environmental and Economic Sustainability Indicators for External Walls

The current context of the intensification of climate changes, on one hand, and the sharp increase in prices in the buildings sector, on the other, impose the need to find solutions that considers both economic and environmental protection aspects.This paper proposes a method of evaluating the solutions most often used today in Romania for the exterior walls in single-family residential buildings based on a global index that takes into account both environmental performances (adjusted thermal resistance, carbon footprint) as well as the economic ones (costs).

Thermal Performance Analysis and Optimization Design of Building Exterior Wall Insulation Layers

Thermal Performance Analysis and Optimization Design of Building Exterior Wall Insulation Layers

When Trees Are Not an Option: Perennial Vines as a Complementary Strategy for Mitigating the Summer Warming of an Urban Microclimate

This study evaluates the potential of Boston Ivy (Parthenocissus tricuspidata) to reduce building surface temperature in a mid-latitude North American city center where vine use for this purpose is uncommon. Vegetation can regulate city summer temperatures by providing shade and evaporative cooling. While planting trees has been a focus for many urban municipalities, trees require space (above and below ground), access to water, costly planting and maintenance, and may only be desirable to some city residents. To explore viable vegetation alternatives with fewer growth constraints, we deployed temperature loggers on the exterior walls of buildings in the urban core of Toronto, Canada, a large mid-latitude city. Perennial vines shaded some walls, while others were bare. These devices systematically tracked exterior surface temperature fluctuations over six months, including the growing season, with full vine-leaf coverage. During peak solar access periods, average daily temperature differentials between vine-shaded and non-shaded building surfaces ranged from up to 6.5 °C on south-facing building exteriors to 7.0 °C on west-facing walls. Models were developed to estimate daily degree hour difference, a metric integrating the magnitude and duration of the temperature-moderating potential of vines. At ambient temperatures ≥ 23 °C, solar radiation intensity and ambient air temperature were positively correlated with vine effectiveness in mitigating the rise in built surface temperature; relative humidity was negatively associated. Installing vine cover on urban buildings in the form of green façades can complement tree planting as cities become hotter due to climate change, and space for growing trees diminishes with urban densification. Future research into the capacity of green façades to regulate outdoor temperature must establish uniform measurement protocols and undertake evaluations in diverse climatic scenarios.

The Study on the Thermal Load of Building Exterior Walls with Aerogel Slurry Insulation under Microclimate Conditions

This study aims to address the solubility issue of aerogel particles in water while maintaining their low thermal conductivity properties. To achieve this, different proportions of aerogel slurry were incorporated into coral sand to develop enhanced insulation materials. The goal is to make these materials more economically viable and promote their practical application in various engineering scenarios. This study conducted experiments to measure thermal and moisture performance parameters. The results show that higher aerogel content increases the sensitivity of thermal conductivity to relative humidity. Compared to the dry condition (0% aerogel content), the thermal conductivity difference is minimal (43.5%), while it becomes significant (108.34%) at 32% aerogel content. Regarding wall loads, the largest discrepancy occurs in microclimate heat-humidity conditions during summer and in pure heat transfer conditions under meteorological data during winter. The 32% ASECSC wall experiences the greatest impact from both heat-humidity and urban heat island effects.

A comprehensive investigation of zeolite/polyurea cooling coating on concrete for building energy conservation

Passive daytime radiative cooling (PDRC) materials are beneficial to energy conservation and emission reduction of buildings. Currently, the design of PDRC coatings for exterior walls and roofs of buildings places excessive emphasis on improving the solar reflectance (Rs) and infrared emissivity (Ei) of the coating, while neglecting other important properties of building coatings, such as adhesion, waterproofness, corrosion resistance, and weather resistance. To address these deficiencies, this work developed a (calcined zeolite)/polyurea (CZ/PU) PDRC coating with excellent comprehensive performance for building exterior walls and roofs, using CZ and PU as raw materials. The CZ/PU coating is prepared using a method that is completely consistent with existing paint production and construction techniques, and can be applied to large-area building surfaces at scale. The Rs of the CZ/PU coating is 97.4 %, and the Ei is 94.4 %. Under direct sunlight in summer, the CZ/PU coating achieved significant PDRC effects under both adiabatic conditions (using test equipment to reduce heat conduction and convection) and natural conditions. The corresponding radiative cooling temperatures are 14.9 °C and 4.4 °C, respectively. In addition, the CZ/PU coating also exhibits excellent water resistance, reducing the capillary water absorption rate of a cement block by 78 %. In addition, the adhesion strength of the CZ/PU coating to the substrate reached the highest rating (rating 0). In particular, the optical properties, radiative cooling function, water absorption, and adhesion force of the CZ/PU coating showed ultra high stability in ultraviolet aging experiments. Energy consumption simulations show that the average energy saving efficiency of the CZ/PU coating on the annual total building energy consumption of ten typical Chinese cities is as high as 13.3 %. The CZ/PU-based coating developed in this work comprehensively considers various issues that may be faced in the practical application of radiative cooling architectural exterior wall coatings, providing an experimental foundation for promoting the application of radiative cooling coatings in buildings.

Technical and Economic Aspects of the Choice of Enclosing Wall Structures with a Similar Heat Flow for Low-rise Housing Construction

This article is devoted to the analysis of multilayer enclosing structures used for the construction of exterior walls of low-rise buildings based on a comparison of thermal and economic indicators. For the calculations in this article, the most relevant and popular multilayer wall designs are selected. The object of the study is the structural solutions of multilayer wall enclosing structures in low-rise housing construction, which are used in the city of Krasnoyarsk. The subject of the study is: the influence of the composition of multilayer wall enclosing structures with a similar heat flow on the estimated cost of their construction for the city of Krasnoyarsk and the estimated cost of 1 square meter of each wall structure is determined. At the moment, the construction of low-rise residential buildings is gaining popularity and is supported by state programs both at the federal level and at the levels of the subjects of the Russian Federation and municipalities. Low-rise housing construction is considered as one of the possibilities of solving the housing problem or improving housing conditions for the population. Multilayer enclosing structures with exterior facade decoration have been widely used in low-rise and multi-storey construction. As part of the study, we considered the most common types of multilayer structures and exterior wall facade finishing options, performed thermal engineering and cost estimates to determine the most profitable option for a multilayer wall structure in low-rise housing construction.

Analysis of thermal characteristics and thermal storage performance of energy-saving phase change thermal storage materials in buildings

In order to explore the thermal characteristics and thermal storage performance analysis of energy-saving phase change heat storage materials in buildings, taking the common exterior wall insulation composite wall structure in southwestern China as an example, the influence of insulation board structure thickness design on the total cost of residential air conditioning energy consumption and insulation board cost is studied, thus clarifying the concept and calculation origin of economic insulation thickness. The experimental results show that by drawing mathematical functions of energy consumption cost, total cost, and insulation material cost in the same 2-D coordinate, it is intuitively demonstrated that the minimization of total cost can be ensured when the insulation thickness is in an economic state, and the specific economic thickness can be accurately calculated through example data. Therefore, specific measures for improving external wall insulation from refined insulation structure design are proposed. It has been proven that the design of the exterior wall insulation layer structure is an important way to improve the overall energy-saving benefits of building exterior wall insulation.

Research on energy-saving construction technology of campus building exterior wall under the restriction of energy consumption quota

Research on energy-saving construction technology of campus building exterior wall under the restriction of energy consumption quota