Walls Of Residential Buildings Research Articles

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.

Probabilistic Analysis of Window Frame Junctions' Thermal Reliability Indicators to Precast Concrete and Brick Walls

The side junctions of metal-plastic block frame windows to the walls of residential buildings at different positions of window frames in the wall cavity are analysed. The duration of thermal failure state by the condensate formation criterion was used as a probabilistic indicator of reliability. The units of uninsulated walls, erected in the second half of the 20th century, have a clearly insufficient thermal reliability level. Thermal insulation of walls according to current design standards in most cases ensures an acceptable of the thermal failure state duration.

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).

Application of the Finite Element Method in Determining the Reduced Heat Transfer Resistance of a Hinged Facade System in Residential Buildings

In this paper, the energy efficiency of a ventilated facade is considered by calculating the reduced heat transfer resistance of a hinged facade system (HFS). We have approved three options for fixing the hinged ventilated facade to three types of walls of residential buildings based on the material of: monolithic reinforced concrete, aerated concrete blocks, and solid brick masonry. The choice of these wall filling materials is due to their wide application, both in new construction and in the reconstruction of existing residential buildings, both in mass development and in private housing construction. The thickness of the insulation is also selected. For the selection of insulation, and in general for the calculation of the enclosing structure, the most important factor is the appearance of a dew point. The dew point depends on the thickness and material of the wall filling, the heat and humidity regime inside the building, and climatic conditions. In this paper, research is carried out in terms of calculating the reduced heat transfer resistance of suspended ventilated facades, taking into account in homogeneities using the finite element method, as well as using the traditional method, taking into account the above factors. A comparison of these calculation methods is made and a conclusion is drawn about the expediency of taking into account point bridges of cold. Through cold bridges, energy losses occur, which leads to a change in the temperature regime in the rooms (temperature decrease) during the cold period of the year, and vice versa, to increased heating of the room during the warm period of the year, which leads to the appearance of a dew point in the wall. On a ventilated facade, the most vulnerable point is the brackets, which belong to the group of point bridges of cold. Based on the calculation results, the best wall filling was determined, which reduces the thickness of the insulation from 30 % to 50 % and reduces the specific weight of the wall structure by 1.25–2.1 times, which significantly affects the load on the building foundation.

Energy, economic and environmental (3E) analysis of residential building walls enhanced with phase change materials

The building sector has recently been responsible for the world's energy consumption growth. Heating and cooling accounts for more than 30 % of building energy consumption. A phase change storage wall heat transfer module considering phase change material hysteresis in TRNSYS was developed in this article. A binary variable is defined to determine the enthalpy curve in heat transfer calculation, which solves the problems of overestimate the latent heat and difficult temperature convergence in the previous hysteresis model for non-complete transformation processes. An extensive study, including energy, economic and environmental analyses, has been proposed to assess the benefits of phase change materials which integrated into building walls in Xi'an. In the study of phase change storage wall building, the energy efficiency, heating and cooling loads of phase change walls with different structures were calculated. It was found that the optimal melting temperature of the phase change layer was close to the summer indoor setting temperature. EPS-Brick-PCM is the optimal phase change insulation composite exterior wall structure. A life cycle economic analysis and carbon emission study were conducted on the phase change wall. It was found that the phase change exterior wall without insulation has better economic efficiency and more carbon emission reduction. The phase change exterior wall with insulation is less economic efficient and has less carbon emission reduction. The thicker the insulation layer of the phase change insulation composite wall, the worse the economic and environmental benefits.

Экспериментальные исследования трехслойных стеновых панелей с наружными слоями из конструкционного бетона и средним слоем из бетона низкой теплопроводности

Three-layer wall panels with a thermal insulation layer made of low thermal conductivity concrete are an alternative solution to single-layer structures made of lightweight concrete and three-layer ones with a thermal insulation layer of effective insulation materials, such as polystyrene foam or mineral wool. For them, the basic principles of designing single-layer lightweight concrete panels are retained, including their reinforcement with spatial frames. These wall panels can be used as load-bearing walls of residential buildings, as well as self-supporting and curtain walls of public and industrial buildings. Tests of full-scale wall panel structures were carried out, which revealed and confirmed the reliability of the monolithic connection of layers between different concrete layers at various stages of the structure’s operation, up to destruction.

Seismic performance and deformation mechanism of precast single-face superposed shear wall

The application of single-face superposed (SFS) shear walls in high-rise residential buildings within seismic zones has attracted extensive attention in past years, but the seismic performance of SFS shear walls hasn't been well understood yet. This study presents the results of quasi-static cyclic tests on four precast SFS shear walls using different horizontal joints and one cast-in-place (CIP) shear wall. The main objective is to achieve a thorough knowledge of the deformation behavior and deformation mechanism of SFS shear walls by analyzing the experimental results describing the global and local deformation behaviors. In general, SFS shear walls behaved equivalently to or even slightly better than the CIP shear wall in terms of bearing capacities, ductility properties, stiffness degradations, and energy dissipation properties. However, unlike the flexure-shear-dominated deformation mode of the CIP shear wall, SFS shear walls were primarily dominated by rigid body rotation behavior and secondarily by flexural-shear deformation. Based on the experimental results, the significant influence of the strain development of vertical rebars, opening, and slip at the horizontal joint on the deformation behavior of SFS shear walls was discussed. It was found that the continuously increasing opening, the sequential yielding of vertical rebars, and the slip at the horizontal joint together led to the difference in deformation behavior between SFS shear walls and the CIP shear wall. Therefore, future work will investigate whether SFS shear walls could emulate well CIP shear walls if the severe deformation at the horizontal joint is greatly reduced.

FDS-Based Study of the Fire Performance of Huizhou Fire Seal Walls in Traditional Residential Buildings in Southern China

In the history of human civilization, traditional villages and buildings have been significantly threatened by fire. As an essential part of Huizhou traditional architecture, fire seal walls play a crucial role in preserving Huizhou architecture by effectively blocking the spread of fire. However, with economic and social development, the Huizhou fire seal wall’s original fire prevention function has been unable to meet the needs of modern fire protection. This study aims to explore the fire performance of different types of Huizhou fire seal walls to provide a reference guide for future fire protection, optimization, and transformation of traditional buildings. In this paper, 3D models of traditional buildings with fire seal walls were built with FDS, and the performance of the different kinds of fire seal walls was simulated under the influence of wind speeds, building spacing, and the height of the vertical ridge of the fire seal wall. The results showed that, under the same conditions, a fire seal wall with a single eave is superior to fire seal walls with quintuple eaves in terms of performance, and fire seal walls with quintuple eaves are superior to fire seal walls with triple eaves in the middle and late stages of a fire. In addition, wind speeds, building spacing, and the height of the vertical ridge have different effects on the fire performance of seal walls. Lower wind speeds can reduce the fire performance of fire seal walls, and no wind and higher wind speeds have no significant effect on the fire performance of fire seal walls, while increasing the height of the vertical ridge and fire spacings appropriately can improve the fire performance of fire seal walls. This study provides a reference guide for future fire protection, optimization, and transformation of Huizhou fire seal walls, which can help improve the fire safety of traditional buildings.

Wind loads tests of external walls blocks masonry of noncombustible polystyrene concrete

Introduction. Blocks of non-combustible polystyrene concrete of D300 density grade, B1 compressive strength class with normalized thermal conductivity λ0 = 0,078 W/(m·°C) and frost resistance grade not lower than F75, developed by LLC “Institute VNIIZhelezobeton”, were used in masonry with a thickness of 375 mm without special fireproof lining. Such masonry successfully passed standard fire tests for fire hazard and fire resistance, which showed the possibility of its use in external non-bearing energysaving walls of multi-storey buildings (up to 25 floors inclusive, about 75 m high).Aim. Evaluation of the strength and deformation characteristics of non-combustible wall masonry made of noncombustible polystyrene concrete blocks with a density of D300 at design wind loads at a height of about 75 m. Materials and methods. Fragments of uncoated wall masonry 375 mm thick, 2,7 m high and 1,2 m wide of noncombustible polystyrene concrete blocks mounted on a mortar with over-all dimensions of 295 × 375 × 595 mm were tested.The test procedure is in accordance with State Standard 8829-2018.Results. The destructive bending load exceeded the calculated one by an average of 4,1 times, while the deflection in the middle of the fragment was 1,9 times less than the permissible one.A methodology has been developed for calculating the strength and deformability of masonry of polystyrene concrete blocks under wind loads, taking into account the influence of horizontal and vertical masonry joints, which is scheduled to be reflected in Amendment No. 1 SP 434.1325800.2018.Conclusions. The results of wind load tests showed that for unlined masonry made of non-combustible polystyrene concrete blocks with a density of D300 and a thickness of 375 mm, the requirements for strength and deformability are met with a significant margin. The results of tests for wind and fire effects of the specified block masonry make it possible to use it in nonbearing external walls of multi-storey residential energyefficient buildings up to 75 m high in virtually all regions of Russia.

Dynamics of tidal parameters depending on the landslide hazard condition of the salt mine roof

The dynamics of tidal parameters were studied based on the results of tilt observations in 4 points of the landslide hazard zone, which was formed over the exhausted field of a salt mine in the city of Soledar, Donetsk region. The reduction in the thickness of the supporting walls of the salt mine led to the loss of their supporting stability, which led to the lowering of the ground, the destruction of the foundations and walls of residential and administrative buildings in a plot 1.3 km long and 0.5 km wide. To eliminate the risk of collapse, the used underground galleries were filled with salt in order to strengthen their retaining walls.Thus, the landslide hazard zone has become a unique training ground for studying the change in tidal parameters γ and Δϕ depending on the state of the mine roof. In total, 256 continuous hourly monthly series were processed using modern methods of excluding their linear drift and anomalous meteorological disturbances from the initial data at short observation intervals, which made it possible to significantly increase the accuracy of determining tidal parameters based on the results of harmonic analysis. For the first time in the global earth tide practice, the normalization of the tilt parameters during and after strengthening the collapsing roof of the mine was revealed. If before the strengthening of the supporting walls of the underground galleries, the tidal parameters assumed abnormal values (the amplitude factor γ by 30 %, and the phase factor Δϕ by 10—15 degrees differed from the regional analogues), then in the process of backfilling they began to approach their regional values, which they reached a year after the backfilling. The real possibility of using the earth tide method for monitoring and forecasting the landslide hazard and related phenomena of the ground has been proven.

Energy saving potential of screen walls in high-rise residential buildings in hot and humid climates

About 33% of the total energy produced, is consumed by the building sector. Especially, 75% of the energy gets utilized by the residential buildings within the building sector. The increased usage of air conditioning systems to cool the indoor environment in hot-humid climatic regions increases the energy requirements of residential buildings. To be specific, high-rise residential buildings are known to be highly energy intensive. It is possible to mitigate the heat transfer into the indoor environment in high-rise residential buildings by shading the opaque facades. Since mutual shading or shading by adjacent building may not be possible at all times for high-rise residential buildings, screen wall can be used to shade the buildings to reduce its energy requirements and provide thermal comfort for the occupants in the indoor environment. In this background, the aim of the current research work is to find out the embodied energy, involved in the implementation of screen wall, and its effectiveness in reducing the operational energy requirements for space cooling in high-rise residential buildings. The option of screen wall and its benefits over conventional building envelope are emphasized in this study through a simulation study. A bedroom in a high-rise residential building in Chennai was chosen for conducting the detailed analysis and the analysis was carried through simulation for one year. The research design includes the modelling of the selected residential building in IES-VE software and validating the results through field measurements. Energy saving analysis was conducted through simulation to determine the energy saved in space cooling by shading the opaque façades with screen wall. For one year, 7.88MWh energy reduction was attained from the installation of screen wall over opaque surfaces at the set indoor temperature i.e., 27°C for 8 hours during night time using air-conditioning. The embodied energy was calculated for the installation of metal sheet over opaque façade and for shading as screen wall and the outcomes were compared with the energy savings in space cooling with the application of screen wall. The payback period for the embodied energy of the screen wall installation was determined in terms of operational energy saved in space cooling through screen walls. The analysis revealed that the payback period is one year. Due to COVID-19 pandemic, people staying at indoors in residential buildings has increased up to 90% during day time, which in turn results in high energy demand. Screen wall acts as a skin for the buildings and shade entirely from the sun. It helps in reducing the energy usage for space cooling in residential buildings, which eventually reduces the carbon footprint.

Application and Prospect of New Masonry Infilled Wall

As a new wall material, autoclaved aerated concrete (AAC) can realize the self-insulation system of "single material" wall in different climate regions in China. At the same time, it has obvious advantages in engineering construction, such as saving resources, easy processing, and good fire resistance. Therefore, AAC can be used as the preferred wall material for infilled walls of frame structures and load-bearing walls of residential multi-story buildings. In this paper, firstly, the main characteristics of AAC blocks are briefly explained. Then, the seismic performance of Reinforced Concrete frame of AAC, the impact of hole characteristics on its mechanical properties, and its compressive properties are analyzed and explored. It is expected that AAC blocks will be widely used and developed in the process of filling construction in the future.

MODERN ARCHITECTURE AND ENERGY EFFICIENCY

The article analyzes the design solutions for the outer walls of residential buildings built in 2020-2022 in a city that belongs to the II temperature zone of Ukraine. The outer walls of the monolithic reinforced concrete frame of the building are made of hollow brick 250 mm thick with a façade system of heat-insulating and finishing class A. A verification thermotechnical calculation of the outer wall was carried out, taking into account heat-conducting inclusions, the reduced heat transfer resistance of an opaque enclosing structure (wall) does not correspond to the minimum allowable value of heat transfer resistance of the corresponding structure according to DBN V.2.6 – 31:2016 for the II temperature zone. When taking into account the effect of air permeability on reducing the overall level of thermal protection of the fence, it was determined that the calculated reduced value of the resistance to heat transfer of the outer wall will be even lower due to the fact that the structure consists of light cellular materials with a significant breathability. External enclosing structures and internal, dividing rooms with a temperature difference of 4 ° C or more, have insufficient insulation thickness. When developing insulation measures, the effect of air filtration through wall structures made of lightweight materials is not taken into account. The requirements for the insulation of complex structural units of enclosing structures to prevent the formation of "cold bridges", for example, a balcony slab, are not met. Translucent structures, which occupy more than 50% of the facades, are the cheapest, their heat transfer resistance is less than the minimum allowable value. Based on the results of the analysis, the main measures to improve the energy efficiency of residential multi-storey buildings were identified to enable the installation of large windows in residential and public buildings in the climatic conditions of Ukraine.

Automatic Wall Painting Robot Automatic Wall Painting Robot

Wall painting is an ideal candidate for automation since it is so repetitive, laborintensive, and potentially hazardous. Painting had already been automated in the car industry, but not in the building industry. It is urgently necessary to paint the interior walls of residential buildings using a mobile robot that can move. In order to provide lateral feed motion to cover the painting surface, the arm of the autonomous wall painting robot described in this study is installed on a mobile robot base and scans the walls vertically. The design aims to satisfy the requirements of simplicity, lightness, affordability, and speedy painting. Ultrasonic sensors are put on the arm and the movable base to allow movement while adjusting the mobility constraints. To organise the movement of the mobile base and govern the arm movement, a control system is developed.

Intelligent radiative thermostat induced by near-field radiative thermal diode

A radiative thermostat system senses its own temperature and automatically modulates heat transfer by turning on/off the cooling to maintain its temperature near a desired set point. Taking advantage of far- and near-field radiative thermal technologies, we propose an intelligent radiative thermostat induced by the combination of passive radiative cooling and near-field radiative thermal diode for thermal regulation at room temperature. The top passive radiative cooler in thermostat system with static thermal emissivity uses the cold outer space to passively cool itself all day, which can provide the bottom structure with the sub-ambient cold source. Meanwhile, using the phase-transition material vanadium dioxide, the bottom structure forms a near-field radiative thermal diode with the top cooler, which can significantly regulate the heat transfer between two terminals of the diode and then realize a stable temperature of the bottom structure. Besides, the backsided heat input of the thermostat has been taken into account according to real-world applications. Thermal performance of the proposed radiative thermostat design has been analyzed, showing that the coupling effect of static passive radiative cooling and dynamic internal heat transfer modulation can maintain an equilibrium temperature approximately locked within the phase transition region. Besides, after considering empirical indoor-to-outdoor heat flux, rendering its thermal performance closer to that of passive solar residential building walls, the calculation result proves that the radiative thermostat system can effectively modulate the temperature and stabilize it within a controllable range. Passive radiative thermostats driven by near-field radiative thermal diode can potentially enable intelligent temperature regulation technologies, for example, to moderate diurnal temperature in regions with extreme thermal swings.

Investigation into the viability of the properties of porous glass-ceramics produced from granite dust and maize cob for use in thermal insulation of external walls of residential buildings

Given the enormous need for cost-effective wall insulation materials in the developing countries and Nigeria specifically, this study, explores the viability of porous glass-ceramics production from granite dust and maize cob using one-step sintering technology. The chemical compositions of the locally sourced materials used including granite dust, ball clay and maize cob were obtained using XRF. 300µm of granite dust and ball clay as well as 425µm of maize cob powder were used. Different amount of granite dust and maize cob powder were mixed with constant amount of a mixture of NaOH and Na2SiO3 in three different groupings to formulate the porous glass-ceramics samples. The formulated samples were uniaxially pressed at 10MPa and sintered in a gas kiln at 850oC for 3 hours. The sintered samples were subjected to experimental tests. The results showed water absorption, apparent porosity, bulk density, compressive strength and thermal conductivity of 25.6%–46.7%, 43.5%–75%, 1.45g/cm3 –1.9g/cm3, 0.7MPa–9.7MPa and 0.11W/m.K–0.53W/m.K respectively. The mineralogical properties of the sintered samples were obtained using XRD. The results indicated a viable material for use in thermal insulation of residential buildings.

Evaluating the Use of Waste Materials in Building Envelopes for Energy Efficiency: A Theoretical and Empirical Study

With the increasing interest in energy-efficient building design, building energy simulation programs are increasingly employed in the design process to help architects and engineers decide which design alternatives save energy more. This research is an empirical and analytical study using a ready-made software package to evaluate the energy efficiency performance of building envelopes using recycled waste material. These methods used available environmental alternatives material in the experiment. To verify the results, two practical cases are tested. Validation is examined by comparing experimentally measured data and computational simulation data during the same summer period time. Real cases with small-scale actual rooms that were used to generate data to validate numerical models. The focus of this study is to compare the experimental measured thermal behavior of traditional and waste materials in residential buildings with simulation results. This comparison allows determining the effect of using waste material in southern walls of a residential building at an indoor temperature during hot summer days, in which the measurements took place during June and July. Meanwhile, the results indicated that the indoor temperature of real models was higher than the temperature of simulation models with about 3°C to 6 °C at measuring time (six summer days). This increase is about o 5.4% to 11.8%. The findings also revealed that the use of waste material in the southern wall of a residential building could decrease the indoor temperature by about 0.2 - 3°C degree compared with the traditional material at the same wall. It means that waste materials in southern walls could decrease 0.9% to 4.1% of indoor temperature compared with traditional materials. This study found that the analytical and empirical small-scale models could contribute to determining the usage of waste material at southern walls of residential buildings. Also, the comparison of the results indicates that Design-Builder can predict indoor temperature to achieve thermal comfort with good accuracy and it can be used by researchers and designers to evaluate the thermal performance of buildings.

Phase change materials: Agents towards energy performance improvement in inclined, vertical, and horizontal walls of residential buildings

The numerical research of a wall (wall or ceiling) in the presence of phase change materials is undertaken in this work due to the relevance of energy consumption in buildings. One side of the wall has a high temperature, and the other side has a low temperature. The phase change materials is placed inside a cavity with an aluminum panel. For better examination, the number of cavities varies from 1 to 15 in the wall. The effect of different ceiling angles from 0 to 90° is evaluated. Graphene nanoparticles are added to increase the thermal conductivity of phase change materials, and the effects of varying the volume percentage of nanoparticles from 0 to 5% are explored. Finally, for phase change materials charging and discharging processes, as well as phase change time and wall temperature, a wall with variable numbers of cavities and angles for nano-phase change materials with varied volume percentage is simulated. The finite element method is used for the simulations by employing COMSOL. The findings of this research show that using nanoparticles in phase change materials decreases the melting time in the charging process and the freezing time in the discharging process, particularly with high volume percentages. Thus, in the cases of 1 and 15, a 5% enhancement in the number of nanoparticles in PCM intensifies the amount of molten PCM by 4.51% and 4.79%, respectively. The addition of nanoparticles also reduces the wall temperature. An increment in the number of cavities causes the charge and discharge processes to become faster. Further, it enhances the molten fraction of phase change materials in the charging process and the solid fraction of phase change materials in the discharging process.

Energy Performance of Integrated Wall and Window Switchable Insulated Systems for Residential Buildings

In this paper, the energy benefits of switchable insulation systems (SIS) are assessed when applied as shades for windows as well as dynamic insulation for exterior walls of residential buildings located in European countries including Belgium and Spain. A series of analyses is performed for detached houses and apartments representing common Belgian residential buildings to determine the energy performance of SIS when deployed to windows and exterior walls and operated using simplified rule-based controls. The analysis results indicate that SIS-integrated windows can achieve significant energy savings for both dwelling types in Belgium, including the elimination of any mechanical cooling and a reduction of up to 44% of heating energy end-use. Moreover, the results show that SIS can offer even more energy efficiency and thermal comfort benefits when deployed to both windows and exterior walls for residential buildings. These energy efficiency benefits are higher, especially for reducing heating needs, for the milder climates of Belgium and Spain. However, it should be noted that the energy performance of SIS could be affected substantially by windows’ orientation and occupants’ behavior.

Evaluating the importance of the embodied impacts of wall assemblies in the context of a low environmental impact energy mix

In the context of a low environmental impact energy mix, the embodied energy of building materials can account for up to 46% of a building's life cycle energy over a 50-year service life. Fifty percent of this energy corresponds to the combination of the structure and building envelope. While most studies have compared different residential building systems or wall assemblies, this study aims to quantify the contribution of initial embodied impacts to the environmental impacts of wall assemblies' life cycle for the exterior walls of an office building in Quebec City (Canada). Cradle-to-grave life cycle assessments were conducted on eight wall assemblies, three of which use light-frame construction, one lightweight steel framing, two cross-laminated timber and two glued-laminated timber in a post and beam approach. The life cycle impacts were evaluated using openLCA, the ecoinvent database and the TRACI method. Energy consumption during the use stage was simulated using EnergyPlus. The results indicate that initial embodied impacts can account for 40% to 66% of all environmental impacts throughout the wall assemblies' life cycle. These results suggest that, in this specific context, the initial embodied impacts can become the dominant source of environmental impacts in wall assemblies' life cycle. Many factors have been identified as affecting initial embodied impacts such as the choice, the quantity and the nature of materials. The results of this study will help decision makers to identify where efforts should be made to reduce a building's environmental impacts in similar context.