Exterior Wall Insulation Research Articles

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.

Prospective life cycle approach to buildings' adaptation for future climate and decarbonization scenarios

The existing building stock is crucial for enhancing decarbonization targets and mitigating climate change. This article delves into a methodological approach that combines prospective life cycle assessment, building thermal simulation using projected future climate data, and global sensitivity analysis to pinpoint the most influential parameters under current climate conditions and future scenarios. The methodology covers plausible decarbonization pathways for the electricity mix, considering the growing utilization of renewable sources, which are influenced by the building locations. An adaptive reuse process involves converting a historic residence into an office building to validate the proposed methodology. Several retrofit strategies are assessed, such as exterior wall insulation, roof insulation, and window replacement. The findings reveal a 12% rise in average usage impacts and a 7% increase in cradle-to-use impacts from the base scenario to future climate projections. Embodied impacts surpass use-phase impacts by 23% in future climates and 33% in certain baseline scenarios. Utilizing future climate data in the life cycle analysis to estimate energy requirements can aid in forecasting building performance under climate change, especially in adapting the existing building stock for enhanced thermal comfort with minimal environmental impact.

Economic optimization of exterior wall insulation in Chinese office buildings by coupling artificial neural network and genetic algorithm

Envelope insulation is an essential measure to reduce building energy consumption and is the focus of many building energy codes. In China, the current standard (GB 55015-2021) only specified limit values for the thermal conductivity (U) of the exterior walls, and it ignored variations in building characteristics and internal parameters. Therefore, it is difficult for architects to quickly determine the exterior wall U-value in building design and retrofit. To address this issue, the exterior wall U-values of office buildings in China were economically optimized by TRNSYS, ANN, and GA. To begin with, the effect of enhancing exterior wall insulation on the heating and cooling energy consumption of office buildings was investigated by TRNSYS software, taking into account variations in building characteristics. Moreover, the exterior wall U-values of office buildings were optimized by coupling ANN and GA. The results showed that the design values of the GB 55015-2021 did not achieve the optimal results in China, and the most economical exterior wall U-value was 0.24 W/(m2·K) in Harbin, 0.24 W/(m2·K) in Beijing, 0.42 W/(m2·K) in Changsha, 1.82 W/(m2·K) in Guangzhou, 0.66 W/(m2·K) in Kunming. Compared with the pre-optimization, the annual life cycle cost of building heating and cooling reduced by 0.96 % in Harbin, 2.07 % in Beijing, 1.44 % in Changsha, 1.68 % in Guangzhou, and 7.37 % in Kunming. In addition, variations in building parameters should be considered in the design phase of new buildings or in the renovation of old buildings, such as internal heat gain, which may lead to different optimal results.

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.

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

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

Optimization Analysis of an Energy-Saving Renovation Scheme for Building Envelopes of Existing Rural Houses Based on a Comprehensive Benefit Evaluation

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

Multi-Stage Sensitivity Analysis of the Energy Demand for the Cooling of Grain Warehouses in Cold Regions of China

The early design parameters exert a considerable influence on the cooling energy demand of a granary building in operation. In order to investigate the impact of various parameters on energy use, a grain warehouse energy model was constructed using the Ladybug + Honeybee tools on the Grasshopper platform. Three global energy sensitivity methods were used to analyze the model, and the sizes of the influential parameters were determined and ranked. The study uncovered that the cooling energy demand of the grain warehouse was primarily influenced by factors such as the cooling set-point temperature, roof solar absorptance, roof and exterior wall insulation thickness, window type, and orientation. On this basis, a local sensitivity analysis was conducted for the highly sensitive parameters to identify their influence trend and optimal design range. The results showed that the cooling energy demand of the grain warehouse increases faster as the cooling set-point temperature decreases, with the highest growth rate occurring at a temperature below 18 °C. Lower solar absorptance of the roof is conducive to reducing the cooling energy demand of the grain warehouse. When the thickness of the roof thermal insulation is less than 120 mm and the thickness of the external wall thermal insulation is less than 60 mm, energy use decreases more quickly with greater insulation thickness. It is advisable to use traditional or new windows with thermal insulation and shuttered windows. Furthermore, the optimal position of the long side of the granary was between 10° west and 10° east of north. This research could provide guidance for the energy-saving design and renovation of granary buildings in cold regions of China.

Experimental and numerical study on seismic performance of prefabricated new fly ash foam concrete structure

In view of the current situation of solid waste resource utilization and the introduction of exterior wall insulation limit policy, this paper proposes a new type of assembled fly ash foam concrete structure for rural areas. After that, a 1:3 scaled specimen model was designed for the proposed static test with three actuators loaded synchronously, and the seismic performance of each floor of the structure was investigated by hysteresis curves, skeleton curves, ductility coefficients, equivalent damping ratios, and stiffness degradation curves, and compared with that of ordinary concrete structures. Finally, ABAQUS was used to establish the structural model with different porosity, and the effects of different porosity on the seismic performance of the structure were determined by comparing the results of tests and finite elements. The results show that the peak load of the assembled new fly ash foam concrete structure model is 84.9 kN, the ultimate displacement is 49.5 mm, the equivalent damping ratio is increased by 24.0 %, and the ductility coefficient is 2.15 compared with that of the ordinary concrete structure, with the increase of the pore rate, the damage location is mainly concentrated from the surface of the specimen to the corners of the doors and windows. The pore rate of 0.101 can simultaneously meet the requirements of structural lighting, economy, and load-bearing capacity. The proposal of an assembled new fly ash foam concrete structure enriches the structural form and lays the foundation for the design and application of this structure in the future.

Optimization of exterior wall insulation in office buildings based on wall orientation: Economic, energy and carbon saving potential in China

The aim of this study is to optimize the exterior wall insulation of different orientations to further reduce the heating and cooling energy consumption of office buildings, and to analyze its economic, energy and carbon saving potential in China. A six-story office building was selected as the case building and its energy consumption was evaluated using TRNSYS, considering variations in latitude, window-to-wall ratio, aspect ratio, and exterior wall U-values of four orientations. In addition, the exterior wall insulation in four directions was optimized by coupling artificial neural network and genetic algorithm. The main results showed that in the 20°N to 40°N region of China, the GA-optimized exterior wall U-values were highest in the southern direction, followed by the eastern and western directions, and finally the northern direction. In addition, overall, the optimal combination of exterior wall U-values showed a trend of high at low latitudes and low at high latitudes, and increased with increasing WWR and decreased with increasing AR. Finally, compared to the exterior wall requirements for energy efficient buildings in GB 55015-2021, the optimized office buildings at low altitude in China showed a 3.26 %, 6.77 % and 6.59 % reduction in ALCC, total energy consumption and total carbon emissions respectively.

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.

Application of new nanopolymer materials in intelligent thermal insulation system for building external walls

In response to the current problem of poor energy consumption control effect and overall high energy consumption of new nanopolymer materials for building exterior walls, the author proposes a thermal insulation energy consumption control technology based on the heat transfer performance model of exterior wall insulation panels. Calculate the current heat transfer performance parameters of exterior wall insulation panels using the reaction coefficient method, determine the proportional relationship between the effective heat transfer coefficients, and establish a heat transfer performance model for exterior wall insulation panels, based on the thermal conductivity index of the new nanopolymer material for the wall, the current control parameters are optimized. The optimal data algorithm is used to obtain the energy consumption decision variable value of the new nanopolymer material for the exterior wall of the building under the condition of clarifying the current heat transfer coefficient, and establish constraint conditions, based on the specific energy consumption data of new nanopolymer materials outside the current wall, establish the current thermal energy information transmission ratio relationship, analyze the current wall energy consumption hotspots, propose the K-means clustering analysis strategy, and apply it to the hot spot clustering control. Energy consumption control is achieved by locating the main cluster head parameters of the hot spot. Simulation results show that the hot spot fit of the aforementioned control methods has been improved by 29%, and the accuracy of the design method in cooling load control statistics is significantly higher than the two traditional methods used for comparison. Due to different weights, the final improvement ratio is determined to be 27%, further verifying the hypothesis. It has been proven that it can effectively improve the energy consumption control effect.

Towards A Design Approach to Achieve Environmental Safety in Diagnostic and Therapeutic Units in Hospitals Using Nanotechnology

In The environmental safety was investigated in this study, with an initial focus on defining the general concept of environmental safety. Subsequently, the study delved into the environmental safety within hospitals, particularly in diagnostic and treatment spaces. Air pollutants and their types were examined, along with permissible levels, emphasizing the adverse effects of increased pollutants on human health. Additionally, attention was given to the physical hazards within these spaces, such as temperature, noise, and lighting. In the context of studying diagnostic and treatment spaces in hospitals, a review was conducted on the currently used traditional finishing materials and an evaluation of their harmful effects. The concept of "sick buildings" and its impact on human safety was also explored. The study placed a particular emphasis on nanotechnology and how nano-materials can be employed to mitigate the detrimental effects of non-compliant "sick buildings" with environmental safety standards. Global examples of nano-applications were analyzed, along with an examination of a hospital in Egypt that utilizes nano-technology in its glass structure. Furthermore, a simulation was performed on a local hospital to measure the difference in carbon dioxide emission within the space. This comparison was conducted between the current state of the building using traditional finishing materials and the scenario where nano-alternatives are employed in the glass and thermal insulation of exterior walls.

Analysis of factors influencing energy-saving advantages of outside and inside insulation of exterior walls in intermittent air-conditioned buildings

An effective approach to reducing building energy is determining the proper insulation location of the exterior walls. Two conflicting conclusions were found in previous research that focused on the optimal insulation location of exterior walls in buildings with intermittently operated convective air systems (CASs). Why conflicting conclusions are produced and which factors influence them have not yet been answered. Thus, this paper analyzes the generation of the transmission load through the exterior walls with outside and inside insulation, and accordingly evaluates the parameters that might affect the energy-saving advantage of two insulation locations. An analytic model is utilized to calculate the heat transfer through the exterior walls. Results show that the heat stored in exterior walls’ inner layer during CAS off-periods is the key to determining the relative energy-saving of two insulation locations. Furthermore, the relative energy-saving increases with thermal capacity of exterior envelopes and air change rate but decreases with the increase in thermal capacity of interior envelopes and setpoint temperature. Based on these, a predictive model is devised to determine the proper insulation location of exterior wall. A critical daily sol-air temperature range beyond which the relative energy-saving advantage transitions is found using the model.

Research on fire resistance of silica fume insulation mortar

Due to the increasingly tight energy supply situation, thermal insulation mortar is more and more widely used in the exterior wall insulation layer of buildings in various countries. However, the existing academic papers have less research on the key properties of thermal insulation mortar such as fire resistance and economic feasibility. Based on the previous research results, this study selected silica fume as an admixture to improve the comprehensive performance of insulation mortar. The goal is to develop a high-performance fireproof insulation mortar. This paper focuses on the fire resistance of the improved insulation mortar. The results show that silica fume mixed into the mortar will play a fine particle filling and hydration gelation cooperation, and the amount of silica fume mixed from 0 to 10% can significantly improve the bond strength and compressive strength of the mortar. For the thermal conductivity and dry density of mortar, there is a certain increase in the range of silica fume dosing from 0 to 4%, while the range of silica fume dosing from 4% to 10% decreases again. Silica fume has a favorable effect on improving the fire resistance of insulating mortar, and the mortar with 10% admixture of silica fume has about 28.30% lower mass loss rate after high temperature and about 14.73% higher relative compressive strength after high temperature after 28 days of maintenance. The final selected optimum admixture of silica fume is 10%, and the best ratio of raw materials is cement: aggregate: water: dispersible emulsion powder: fly ash: diabase rock powder: AOS foaming agent: gelatin: silica fume = 1: 1.67: 2: 0.045: 0.15: 0.225: 0.035: 0.02: 0.138.

Study on the Performance of Active Embedded Steel Wire Knot Form in Silicone Graphene Composite Thermal Insulation Structure Integrated System

Based on the advantages of the silicone graphene composite thermal insulation board, it was used to replace traditional plywood in the external wall formwork system, and the active embedded steel wire knot form in silicone graphene composite thermal insulation structure integrated system was designed. Firstly, the theoretical model of steel wire drawing resistance was established by theoretical analysis method, and the rationality of the theoretical model was verified by combining relevant experimental data. The relationship between multiple variables and steel wire pull-out resistance was analyzed. Then, combined with the theory of wind pressure strength of the exterior wall of a building structure, the layout form and the corresponding number of embedded steel wires of thermal insulation board under different building heights were analyzed. Finally, the silicone graphene composite thermal insulation board and ordinary plywood were compared and analyzed from the force of perspective of external wall formwork. The results showed that the pull-out resistance of steel wire was directly proportional to the diameter of steel wire, embedded depth, and embedded deflection angle. With the increase of building height, the number of steel wires to be arranged also increased. When the thickness of the silicone graphene composite thermal insulation board is not less than 80 mm, the anti-deformation effect is close to that of the ordinary plywood, which can meet the construction requirements of the external wall formwork. It can ensure the energy conservation and thermal insulation of the external wall, integrate the building’s exterior wall and thermal insulation structure of the building, and achieve the purpose of exemption from formwork removal.

Developing light transmitting concrete for energy saving in buildings

Energy consumption is constantly increasing all around the world, and one of the substantial energy consumption fields is the electricity required for lighting in buildings. There are various approaches to tackle this problem, among which the use of transparent facades is the common method to reduce electrical energy consumption in modern buildings such as museums; However, these solutions have many problems, such as space security, heat gains during summer, and glare; The main problems related to transparent facades are energy loss through light transmitting seams and visual discomfort. Hence, it is necessary to develop a new method that can pass natural light to enhance visual comfort without damaging the thermal insulation of the building's exterior walls. One solution that can be given to this issue is using light transmitting concrete. In this study, five high-performance light transmitting concrete samples, including the different amounts of optical fiber were made, and their performances in terms of daylight and electricity saving have been analyzed based on simulation with Diva for Rhino software. For a better comparison between different studies, the analysis was done based on the reference office, which had been used in previous relevant studies. As a result, the reference office was modeled in 6 cities (Tehran, Houston, Phoenix, San Francisco, Vancouver, & Chicago). It was found that using this material along with using lighting sensors resulted in 45.7%, 31.5%, and 38.8% electricity saving for offices in Tehran, Vancouver, and Phoenix, respectively, and also can increase UDI (Useful Daylight Illuminance) by about 39% in Tehran.

Energy, exergy analysis and optimization of insulation thickness on buildings in a low-temperature district heating system

In the study, energy and exergy analysis of the buildings on a campus in Turkey are conducted by using actual operating data and taking measurements in the district heating system as a case study. The energy and exergy demands, losses that stem from all buildings are calculated according to average daily outdoor temperature data. Due to the high heat losses in the buildings, determining the optimal insulation thickness for the exterior wall should be investigated. Therefore, optimal insulation thicknesses, energy savings, fuel consumptions and payback periods of the insulation material on the exterior wall of the building are examined by using Life Cycle Assessment and P1–P2 method for natural gas. Optimal insulation thicknesses are calculated for different insulation materials such as XPS, glass wool, rock wool and EPS for the climatic regions (HDD=800–4250°C days). According to average exergy losses from the building components per unit area, the average total exergy loss is calculated as 2.39×10-2 kW/m2.year and 1.42×10-3 kW/m2 (5.92%) of this loss stems from the exterior walls, 1.93×10-3 kW/m2 (8.07%) from the floors, 7.37×10-4 kW/m2 (3.08%) from the roofs, 1.58×10-2 kW/m2 (65.99%) from the windows and doors, 4.04×10-3 kW/m2 (16.92%) from the ventilation with infiltration. Energy requirement values of the building are found between 2.68–25.70 kWh/m3 towards from the warmest to the coldest climatic region for the uninsulated wall. In the un-insulated state, fuel consumption varies between 1.93-18.48 m3/m2 from the warmest to the coldest region. The optimal insulation thickness values of the building’s exterior wall are calculated as between 2.3–10.0 cm according to different climatic regions. In-state of exterior wall insulation of 3 cm, fuel consumption decreases by 46.63%–53.46% compared to different insulation materials and climatic regions compared to the un-insulated state.

Wall Insulation Materials in Different Climate Zones: A Review on Challenges and Opportunities of Available Alternatives

Buildings account for nearly one-third of overall energy consumption in today’s world energy status, in which a considerable part is used for indoor conditioning. Energy efficiency enhancement of buildings components and technologies is a key priority, given the essential need for carbon neutrality and climate change mitigation around the world. Exterior wall insulation is considered as the most effective technology for protecting buildings against continual ambient fluctuations. Proper design and implementation of wall insulation would lead to performance enhancement, energy conservation as well as improved thermal comfort. They can also protect building structures against corrosion and heat fatigue, extending the life of buildings. There are many different types of thermal insulation materials currently on the market, each with its own set of thermal qualities and functionality. This paper aims to examine the qualities, benefits, and drawbacks of several exterior wall insulation technologies, and provide recommendations for how to use various forms of exterior wall insulation in different climates.

Application Progress of Aerogel / Inorganic Cementitious Composites in Building Thermal Insulation

In recent years, the problem of energy saving and consumption reduction in the construction industry has attracted more and more attention. The state has also put forward higher requirements on the energy saving, environmental protection and fire safety of building exterior wall insulation in terms of policies. Aerogel materials are considered to be the most promising thermal insulation materials in the future due to their excellent thermal insulation properties and fire resistance. In this paper, the preparation process and application of aerogel inorganic cementitious composites were investigated, mainly aerogel cement composites and aerogel gypsum composites. We analyzed the recent research results, and focused on the preparation optimization and application prospects of aerogel inorganic cementitious composites. In the preparation of aerogel inorganic cementitious composites, many researchers have proposed different preparation methods to optimize the interface between aerogel and inorganic cementitious materials in order to avoid the strength degradation caused by doping aerogel. At present, preparing aerogel into aerogel slurry for compounding is considered to be a relatively optimal incorporation method. It is found that aerogel inorganic cementitious composites have great prospects for thermal insulation applications in the construction field. However, due to the high cost of aerogel preparation and the poor interfacial bonding between aerogel and inorganic cementitious materials, the application of aerogel in building thermal insulation is limited. This paper has reference significance for studying the application of aerogel in the construction industry.