Residential Building Envelope Research Articles

Evaluation of the Summer Overheating Phenomenon in Reinforced Concrete and Cross Laminated Timber Residential Buildings in the Cold and Severe Cold Regions of China

As the climate changed in recent years, an increase in summer indoor temperatures in severe cold and cold regions of China has started to affect thermal comfort. However, the local design standard for energy efficiency does not recognize this phenomenon. This paper reports the potential overheating phenomenon in residential buildings and examines the rationale for the current thermal designs adopted in severe cold and cold regions of China. In this study, the two most commonly used building materials, reinforced concrete (RC) and cross laminated timber (CLT), are used separately in the design of an 18-story residential building envelope located in six different cities in the severe cold and cold regions. The energy consumption and indoor operative temperatures during the operation of these buildings are simulated using Integrated Environmental Solutions Virtual Environment (IES VE). The results demonstrate that both the RC and the CLT buildings experience varying degrees of overheating in any climate subregion. The CLT buildings have longer overheating hours compared to the RC buildings, especially in the cold regions. The results also indicate that for apartments on higher stories, the cooling energy consumption and indoor temperature also increase gradually. The research results suggest that the local design standard for energy efficiency needs to be adjusted by adding thermal design methods for summer to reduce the periods of overheating.

Indoor Air Design Parameters of Air Conditioners for Mold-Prevention and Antibacterial in Island Residential Buildings.

The climate characteristics of the islands in the Nansha Islands of China are a typical marine climate including high temperature, high relative humidity, high salt content, strong solar radiation, and long sunshine. These can provide suitable conditions for mold reproduction on the surface of the wall in a building. Therefore, mildew pollution on the wall for a long time can easily damage the building’s structure. It does not only directly affect the appearance of the building, but also indirectly affects the indoor environment and human health. In this paper, dominant fungi in the residential buildings on thee Nansha Islands of China are Aspergillus, Penicillium, and Cladosporium. Critical lines of temperature and relative humidity for mould growth on the interior surfaces of island residential building envelopes have been given and discussed. The results show that the risk of mould growth on the wall with different materials, from low to high, is reinforced concrete, aerated concrete block, coral aggregate, brick, and wood. Furthermore, in order to prevent the room regulated by air conditioner from being contaminated by mould, indoor air temperature should be set variable and controlled between 26 °C and 28 °C, the relative humidity should be changed between 50% and 80%.

Optimization of residential building envelopes using an improved Emperor Penguin Optimizer

Energy consumption minimization and the lowest life cycle costs are two important factors in residential buildings. Therefore, to achieve the optimum shape with the best performance, a new optimization-simulation technique, called improved Emperor Penguin Optimizer coupled with a building energy simulation tool, called eQuest have been provided to choose optimum values of an all-inclusive list of criteria related to the envelope for minimization of the energy consumption of the residential buildings. Generally, the process of model optimization can take less computation time and cost. Also, the applied method carries out completely well comparing the particle swarm, approaching very near to the optimal in less than 50% of the simulations. Among different forms that have been evaluated in this paper, the trapezoid and the rectangle forms had better results with the fewest amount of the life cycle costs in all five various climate conditions. Also, considering the worst and the best alternation of the form, the trapezoid, and the rectangle showed the smallest value. The characteristics related to the building envelope analyzed were the types of foundation, different types of windows with various areas, the constructions of the roof and the wall, and the insulation of the ceiling and the foundation.

Analysis of Heat Balance in a Light Steel Frame Residence with Different Insulating Thickness

Sustainability and efficiency in buildings are concepts that have been recently growing and developing. Its application in several buildings has become mandatory in many countries around the world. One of the major challenges faced by sustainable buildings is the achievement of satisfactory levels in efficiency terms, without negatively impacting the economics. The residential construction sector has great potential for energy savings and is also where building strategies need to be carefully planned, as they seek to meet the needs of residents not only in the present, but also over time. Residential design must be done thoroughly and must include the analysis of all climate variables involved. In order to verify a residential building envelope behaviour regarding energy and thermal efficiency, this paper intended to evaluate through software Design Builder®, walls and roofs with a rock wool layer, placed in a Light Steel Frame (LSF) house.
 Keywords: Insulating materials, Light steel frame, Heat gains, Heat losses

Embodied and Operational Energy Analysis of Passive House–Inspired High-Performance Residential Building Envelopes

Abstract High-performance building envelopes are designed to achieve target reductions in operational energy (OE). However, these wall assemblies often require initial, upfront investments in mater...

Quantitative Analysis and Multi-Index Evaluation of the Green Building Envelope Performance in the Cold Area of China

In China, relevant standards about building energy efficiency and green buildings have resulted in corresponding requirements for the envelope thermal performance. However, improvement of the thermal performance of the envelope is accompanied by an increase of the environmental impact and cost. This study quantitatively analyzed the thermal performance, environmental impact, and cost of the green building envelope in cold areas and established a common practice database, as well as a multi-index evaluation model. The results show that the best thermal performance improvements are 40% in residential buildings and 30% in public buildings, respectively, based on the relevant standards. The exterior walls and windows have the greatest impact on building heat consumption. There is no significant correlation between the heat consumption and the comprehensive heat transfer coefficient of 10 green buildings. Therefore, the comprehensive heat loss coefficient is corrected. The verification results show that all errors except project 10 are within 15%. Additionally, the projects with balanced thermal performance improvement of exterior walls and windows showed a better performance. Finally, the best combination of residential building envelopes in the cold area was selected, using the evaluation model and quantitative database to calculate the comprehensive score.

Evaluation of the Environmental Performance of Residential Building Envelope Components

The role of buildings in the context of addressing the consequences of climate change and the energy deficit is becoming increasingly important due to their share in the overall amount of green house gas (GHG) emissions and rapidly growing domestic energy consumption worldwide. Adherence to a sustainability agenda requires ever-increasing attention to all stages of a building′s life, as such approach allows for the consideration of environmental impacts of a building, from design, through construction stages, until the final phase of a building′s life—demolition. A life cycle assessment (LCA) is one of the most recognized and adopted models for the evaluation of the environmental performance of materials and processes. This paper aims to perform an LCA of four different types of residential buildings in Nur-Sultan, Kazakhstan. The assessment primarily considered embodied energy and GHG emissions as key assessment indicators. Findings suggest that the operational stage contributed to more than half of the GHG emissions in all the cases. The results of the study indicate that there is a dependence between the comfort levels and the impact of the buildings on the environment. The higher the comfort levels, the higher the impacts in terms of the CO2 equivalent. This conclusion is most likely to be related to the fact that the higher the comfort level, the higher the environmental cost of the materials. A similar correlation can be observed in the case of comparing building comfort levels and life-cycle impacts per user. There are fewer occupants per square meter as the comfort level increases. Furthermore, the obtained results suggest potential ways of reducing the overall environmental impact of the building envelope components.

Performance assessment of residential building envelopes enhanced with phase change materials

Residential buildings in India account for ~22% of the national electricity consumption, of which one-third is used for space cooling; however, they are rarely constructed with energy-efficiency considerations. This presents an opportunity for reducing the energy consumption and associated greenhouse gas (GHG) emissions by design and construction of energy-efficient houses. Therefore, this investigation assessed the potential of PCM-enhanced building envelopes for reducing the cooling energy requirements of residential buildings in Delhi (capital of India). Through numerical simulations, we studied the impact of key PCM design parameters such as its thickness, position, melting point temperature and latent heat capacity on the proposed energy benefits, and compared them with those obtained with insulation-enhanced envelopes. We found that, applying a PCM layer on the roof reduced the summer heat gain by 12.6%–36.2%, whereas an insulation layer of the same thickness reduced heat gains by 41.0%–71.4% over the baseline construction. PCM-enhanced walls were also found to reduce the heat gain by 10.4%–26.6%, while insulated walls led to a heat gain reduction of 32.4%–64.0%. By extrapolating these results to city-scale, it appears that PCM/insulation-enhanced envelopes could reduce Delhi's annual electricity consumption and GHG emissions by 0.3%–1.5% and 0.2%–1.0%, respectively.

Sensitivity energy analysis for the Saudi residential buildings envelope codes under future climate change scenarios: the case for the hot and humid region in Jeddah

The residential building sector of the Kingdom of Saudi Arabia (KSA) is the primary consumer of energy consumption, using around 50% of the total amount of electricity KSA generates. Much of this is caused by the heavy demand for air conditioning due to the extremely high temperatures in the country. On the basis of KSA’s government initiatives, it is compulsory that new residential buildings adhere to strict energy codes. This study places its focus on analysing the ability of KSA’s new residential building envelope codes to successfully function according to the climate at present and in the future. In Jeddah, KSA, two single-family villas were examined with DesignBuilder simulation software and impacts of the new codes that were applied were assessed. Achieving the validation of the energy model requires the measurement of temperature indoors and outdoors. In addition, a long-term financial study was conducted to analyse the economic feasibility of the codes under the current and future climate change periods. Although the study shows the new codes produce a reduction in energy consumption by 14% to 40 % from the current cases, with the inclusion of wall and roof insulation being the most effective features of the new requirements of the codes. However, these codes cannot nullify the effect of future climate change.

Life cycle assessment of rammed earth made using alkaline activated industrial by-products

Given increasing environmental concerns, lower energy building materials are being developed to reduce greenhouse gas emissions. The ancient technique rammed earth has been combined with modern industrial waste products to both reduce greenhouse gas emissions and reduce waste. The new rammed earth mixes have been developed using alkaline activation (sodium hydroxide) of industrial by-products: fly ash, ground granulated blast furnace slag and silica fume. This paper explores the ‘cradle-to-gate’ life cycle assessment, assessing global warming potential of these rammed earth materials, considering acquisition of raw or recycled materials and processing to final product of residential building envelope. These are compared with commonly used building envelope materials, brick veneer and cavity brickwork, and the more common rammed earth variety, cement-stabilised rammed earth. Results show that greenhouse gas emission savings can be made using these rammed earth mixes compared to the control building materials while achieving comparable or better material properties. Greenhouse gas emissions associated with the building envelope materials are reduced by more than half or one third when compared to cavity brickwork or brick veneer respectively. Following testing of the waste products in surplus in a given area, the same process could be followed for any geographic location.

The Design of Sustainable Retrofitting Strategies and Energy-efficiency Optimization for Residential Buildings

There is a huge stock of existing residential buildings in China, with high energy consumption but low comfort, so it is of great significance to retrofit the residential buildings in order to enhance energy-efficiency of the buildings. In this paper, residential buildings, built between 1980 and 2000 in typical cities of the Northeast China, are defined as the research objects. This project tries to systematically put forward an applicable design method and an overall retrofitting plan of residential buildings. Dealing with the issues of the existing research on practical retrofitting of residential buildings in China, such as short of basic data and statistics, neglect of preliminary design planning and lack of guidance evaluation criteria, this project, based on the classification of residential building envelope system, builds a façade system information modelling database of residential buildings in typical cities of the Northeast China and abstracts a design prototype. Relying on the design prototype, Matrix method is used to organize, discover and edit the retrofit design strategies. BIM - EnergyPlus integrated technique is also introduced to evaluate and optimize the design strategies suitable for reference methods for realizing the sustainable retrofitting and energy efficiency optimization. The findings of this research will extend and improve the role and scientificity of architectural design in the retrofitting of residential buildings.

Impact of Low-Income Home Energy-Efficiency Retrofits on Building Air Tightness and Healthy Home Indicators

We studied 226 low-income households as a part of the Colorado Home Energy Efficiency and Respiratory Health (CHEER) study to investigate the relationship between energy-efficiency retrofits (EERs) specific to air sealing of residential building envelopes, annual average infiltration rates (AAIR), and qualitative indicators of “healthy” homes. Blower door tests quantified the leakage area in each home, which was used to estimate the AAIR. Walk-through inspections were used to record observations of air-sealing retrofits conducted as part of Colorado’s Weatherization Assistance Program and indirect indicators of poor indoor environmental quality (IEQ) in the homes, such as visible mold or stains, visible dust on hard surfaces, vapor condensation on windows, dampness, and perceived air quality. Results showed that building characteristics like age and volume affected AAIR more significantly than air-sealing EERs. Among the air-sealing EERs, homes with the air-handler ductwork sealed and windows weather-stripped were found to have significantly lower AAIR compared to the homes without these features. Mold growth, wall stains, notably higher levels of dust, and unacceptable odor levels were more frequently reported in homes with higher AAIR, showing that leakier homes do not necessarily have better IEQ.

Energy impact and eco-efficiency of the envelope insulation in residential buildings in Turkey

Approximately 31% of the energy requirement in Turkey is related to residential buildings. For this reason, residential buildings have an important role in reducing energy needs and greenhouse gas emissions. In this study, a procedure for determining the optimum thermal insulation thickness to be applied to the envelope (external walls, column, floor and roof) of residential buildings by using the heating-cooling energy requirement is presented. The heating and cooling loads and energy costs for different structures are calculated using the optimum thermal insulation thicknesses. Turkey is divided into four climatic zones in relation to their average temperature degree-days of heating according to the Turkish Thermal Insulation Standard. The methodology is applied to a residential building as a case study by comparing 4 insulation materials for 20 different energy demand scenarios for four different cities each representing a different climatic zone of Turkey. Once the global warming potential and cost indicators that is based on the Life Cycle Assessment have been obtained, the eco-efficiency analysis for each scenario are represented using eco-efficiency graphs.

Analyzing optimum thickness for combination of two thermal insulation materials for building walls

This paper reports an approach for analyzing optimum thickness for combination of two thermal insulation materials for walls of residential buildings on the basis of life cycle cost. Two thermal insulation materials for achieving contrast purposes can be use as a solution in many applications e.g. if fire resistant material added with Expanded polystyrene (EPS) to improve its fire resistance property, its thermal conductivity increases, where as if we select glass wool as thermal insulation material it has higher thermal conductivity but better fire resistant, thus if we wish to achieve high thermal resistance with better fire resistance at low cost we can use in place of single thermal insulation material a combination of two thermal insulation materials. In order to determine optimum thickness for combination of two thermal insulation materials there is a need to develop an approach, through which optimum insulation thickness for different combination of two thermal insulation materials on the basis of life cycle cost can be analyzed. To study the effect of fraction of one thermal insulation on optimum thermal insulation thickness proposed approach is applied to insulate external wall of a residential building envelope in heating application. Developed total cost objective function analyzed with the help of surface plot. In order to apply the developed approach EPS and glass wool are considered as thermal insulation materials. Through this approach optimum thickness for combination of two thermal insulation materials can be analyzed on the basis of life cycle cost in order to select best combination of thermal insulation materials as per requirement.

THE EFFECT OF EXTERNAL THICKNESS AS A PART OF BUILDING ENVELOPE ON THE EFFICIENCY OF ENERGY CONSUMPTION IN RESIDENTIAL BUILDINGS (CASE STUDY: RESIDENTIAL BUILDING IN 6TH OCTOBER CITY)

The energy consumption increase in a whole world considers as a warning about the depletion of resources and also increasing the negative impact on the environment (global warming, climate change, thermal island phenomenon, etc.). Where the building consumes 40% of total energy and produces 30% of the world's CO2 emissions. [1]The thermal performance of the building’s envelope (Walls – Opening – Ceiling – Flooring) is also considers as a serious problem because it works to consume energy to achieve the requirements of thermal comfort inside the buildings. The thermal loss of single-storey buildings is estimated about 45% of walls and outside windows, 42% of surface and ground and 13% of air leakage. While the thermal loss in the multi-storey building (5 floors) is estimated about 70% of the walls and outside windows, 13% of the surface and ground and 17% of the air leakage. [2] As a result, the exterior of the building is one of the most important factors affecting the thermal comfort and energy efficiency of residential buildings according to the Solar Radiation.Therefore, the efficiency of energy consumption in residential buildings is one of the new trends that the world is currently heading towards where the building can achieve energy efficiency through the treatment of the external walls of residential units as one of the components of the building envelope in accordance with the requirements of the Egyptian code and the principles of environmental design.The aim of this study is studying the effect of external wall thickness as a component of the building envelope in achieving efficiency of energy consumption and increase the comfort of residential units in the 6th of October City one which considers as a one of new city that allows to create new residential projects (unit with one direction). This effect is examined in the following directions: East - West - South.The methodology includes reviewing the literature and methods that used to address the external envelope of residential buildings to achieve energy efficiency. A practical study was carried out by simulating a housing unit to inherit the effect of external wall thickness as a component of the external casing of a single-oriented residential unit in the 6th of October city in the directions (south – east - west) on the efficiency of energy consumption. The change in thickness of the wall from 12 cm to 25 cm in the south direction reduced the energy consumption by 13.13% and in the case of the use of double wall thickness of 12 cm with 10 cm air cavity 17.2%, while in the east direction the reduction in energy consumption at 25 cm was 14.33% while in the case of using a double wall thickness of 12 cm with 10 cm air cavity 18.65%, and finally in the case of west direction, the reduction in energy consumption at the thickness of 25 cm 15.26%, while in the case of a double wall thickness of 12 cm with a cavity of 10 cm 22.79%. Then the research concludes with some recommendations on how to reduce energy consumption by 46% and improve thermal performance in residential buildings by building envelope treatment not only by the thickness of the wall but also by the material of the wall, type of glazing, and covering the ceiling in case of exposed to the solar radiation.

تقییم الغلاف الخارجی للمبانی السکنیة فی مدینة نجران السعودیة من منظور بیئی

The trend towards environmental designs that contribute in reducing energy consumption and adapting to the environment is a major challenge for city planners, architects and all members of the community, so that most of the world is going to re-evaluate the current and future status of buildings and their suitability to the surrounding environment. Residential buildings in Najran are an important part of the city's built environment. The neglect of the environmental dimension in the design of the outer envelope of this type of buildings is the reason for increasing energy consumption and distortion of the visual image of buildings. The main reason for this is often incorrect decisions in handling the environmental and social aspects of this type of building. The study aims mainly at studying the design of the outer envelope of residential buildings in Najran city and its suitability to the surrounding environment in order to improve the internal environment of the residential spaces. This is done by assessing the outer envelope of these buildings environmentally and socially; to identify the most important problems faced, and to propose and evaluate treatments; to come up with a number of recommendations that will help the designer in making future decisions; in addition to providing treatments that improve the status. To achieve a better residential environment and the impact of compatibility with the environment in which they are located; Using the analytical approach and field visits through which the current situation is analyzed and evaluated

Analysis of climate adaptive energy-saving technology approaches to residential building envelope in Shanghai

In areas having both a hot summer and cold winter, there are two features that affect energy use. One is the high demand for cooling and heating, especially the cooling requirement in summer; the other is the intermittent energy use mode, which depends on whether people are at home. Over recent decades, the average environmental temperature has risen continually, and thus the building cooling load has increased significantly. At present, technological approaches to the building envelope are based on the continuous energy use mode, which needs to be optimised to fit in with local climate characteristics and energy use habits. The orthogonal analysis method is used to optimise the index values of the building envelope capacity by using energy consumption simulation, and experiments are performed to verify a suitable way of using thermal insulation layers to insulate the envelope structure. From the results, it is concluded that thermal reaction rate can be used as a factor to judge the performance of different thermal insulation types. Under an intermittent energy use mode, interior thermal insulation has a higher thermal reaction rate and lower energy consumption. In order to conserve energy, different combinations of envelope index levels are proposed for heating and cooling modes. After building with this optimised energy technology approach, it is expected that thermal comfort can be achieved with a relatively low level of energy use.

Predicting energy generation from residential building attached Photovoltaic Cells in a tropical area using 3D modeling analysis

Energy generation by photovoltaic (PV) installations on residential building envelopes in tropical area was evaluated by using a new practical method employing 3D analysis. Calculations of monthly global radiation were used to investigate solar potential in the study case area. In order to simulate optimal locations of PV panel installation, BIM Revit software was used to quantify the incident solar radiation and for color rendering of different levels experienced in different areas of the building envelope due to Sun path and the influence of the local environment. The amount of energy generated by hypothetical PV panels was compared to actual residential sector energy consumption which became a baseline for evaluating the prospective implementation of PV in a tropical area. The results indicated that the optimal location for installing PV panels was on the roof of a building where incident solar radiation levels are high and uniform throughout the year. In addition, the walls of the building oriented to the East and West have a great potential to harvest electrical energy as an optional location for photovoltaic panel installation. The potentially available photovoltaic energy generated was compared to the actual electrical energy consumption and demonstrated a favourable surplus for electrical energy supply. The energy surplus provided by three types of photovoltaic output varied from 172% to 1700% above the baseline consumption, thus installing photovoltaics on residential buildings could have a strong potential to secure both current energy consumption and future energy demand.

Multistory building envelope: Creative design and enhanced performance

The paper presents a comparative study of three strategies in the design of the building envelope of multistory residential buildings combining enhanced energy performance and architectural innovation. The first strategy, serving as base case, employs a high performance flat façade, applied to a building of square layout. The second strategy introduces multifaceted facade geometries, comprising plates of varying tilt angles, to the same building layout, in order to assess the impact of envelope geometry on energy performance. The third approach investigates the impact on energy performance of varying building layouts as applied to flat and multifaceted facades. British Columbia (Canada) serves as location of the study, representing northern climate conditions.For all three design approaches, the most important stage towards achieving high performance is to design an energy efficient building envelope. Comparison of energy performance of complex façade geometries to the base case, indicates that these geometrical patterns do not significantly compromise the thermal performance of the building, while enabling a considerable increase in the electricity generation potential by integrated photovoltaic systems. In folded-plate façade systems, this increase in PV potential is observed on per unit area basis as well as per total façade area. In addition, some of these façade patterns allow time spread of useful electricity generation of the BIPV systems. Combining folded façade geometry with building layouts that allow large south and near south exposure has the potential of enabling energy positive status. While the paper focuses on residential buildings, the methodology can be applied to any type of high-rise building.

Consequences of energy retrofitting on the daylight availability in Norwegian apartments

Energy retrofitting solutions applied in residential building envelopes often consist in adding an insulation layer on the building facade and substituting the old windows with better performing ones. Such measures increase the thermal insulation of the envelope and reduce the energy need for space heating, but also reduce the daylight availability, due to the lower visible transmittance of highly insulated windows. This drawback may have strong effect in Norway, where the daylight availability in the winter season is little. This paper investigates into the consequences on energy use for space heating and electricity use for lighting given by the substitution of existing windows with highly insulated windows in Norwegian residential buildings. Three apartment buildings with different construction systems of the external facades and located in Trondheim are investigated. The buildings were built before the 1900, in the first decade of the 1900, and in the 1960s, respectively. The U-value of the external facades varies from 0.96 W/m2K to 0.26 W/m2K, and the U-value of the existing windows varies from 1.6 W/m2K to 2.8 W/m2K. The new windows have a U-value of 0.5 W/m2K. Scenarios are modelled to simulate the use patterns of artificial lighting in the apartments. Use patterns are modelled by considering occupancy hours and type of activity to cover different scenarios. Results show that the substitution of the existing windows reduces the median value of the Daylight Autonomy by at least 50%, and the additional electricity use for lighting is calculated to be between 17% and 64% of the potential energy saving for space heating.