Residential Buildings In China Research Articles

Green retrofit of existing residential buildings in China: An investigation on residents’ perceptions

Green retrofit of existing residential buildings is a sustainable way to improve the energy efficiency. However, such implementation faces some challenges due to the different willingness of residents involved. There is a lack of comparative study on residents’ preceptions of green retrofit in China, which is of great concern to the government. Therefore, this study investigates residents’ housing conditions and their perceptions of a green retrofit, based on the feedbacks from 9936 questionnaires which are collected from urban and rural residents throughout China. The Chi-squared test is employed to identify the key influencing factors, including demographic and housing characteristics. The results show that more than 90% of the respondents are willing to adopt retrofit, and installing a zoned temperature control system of individual rooms is a generally acceptable measure. The retrofit subsidy is a topic of high concern, and the respondents are more likely to undertake unified free retrofit, compared with separate retrofit supported by a partial subsidy. Besides, household income, city of residence, housing type and housing problems will cause significant differences in residents’ perceptions. After evaluating the retrofit potential of different resident groups, some suggestions are proposed for policymakers. The findings from this study can help develop differentiated strategies for residents, to promote green retrofit of existing residential buildings in China.

Homeowners’ Willingness to Make Investment in Energy Efficiency Retrofit of Residential Buildings in China and Its Influencing Factors

In China, energy efficiency retrofit of residential buildings is entering a new stage in which homeowners are the main subject. In order to investigate homeowners’ willingness to invest and to analyze its influencing factors, interviews and a questionnaire survey were conducted in central Tianjin, China. The results show that homeowners have a certain willingness to invest in energy efficiency retrofit but that their willingness to pay (WTP) is far from enough to cover the total cost. Among the influencing factors, the homeowner’s age, education level, and retrofit experience as well as the age and floor area of their home are significantly related to their WTP. The reasons for the impact of these factors are further discussed, including the influences of China’s previous housing policies and retrofit policies. Policy recommendations to promote investment by homeowners are suggested based on the findings.

Dynamic global warming impact assessment integrating temporal variables: Application to a residential building in China

Climate warming is a global concern, and buildings have been recognized as a major contributor because the carbon emissions during their entire life cycles constitute a large share of the total value (almost 40% globally). Many life cycle assessments of buildings have been conducted to quantify the associated global warming impacts. However, few studies have considered the potential temporal variation over the long lifetimes of buildings. In this study, various temporal variables were combined to evaluate the dynamic life cycle global warming impact of a residential building in China. First, annual material and energy consumption data throughout the entire life cycle were acquired from questionnaire survey, statistical reports and literatures. Five dynamic variables (household size, usage behavior, replacement and improvement of components, waste treatment, and energy mix) and their effects on consumption levels were considered. Second, a dynamic inventory analysis tool (DyPLCA) was used to transform the temporal consumption data into dynamic greenhouse gas quantities. The global warming effects of these emissions were quantified using a dynamic characterization tool (DynCO2). Finally, emission reduction targets for future decades were used to weight the severities of the impacts at different times. The dynamic instantaneous and cumulative global warming impacts of the building were calculated. Dynamic and static assessment results were compared. We also analyzed the contribution of each dynamic variable to the final results and found that the dynamic variables had very different effects (ranging from −42.00% to 45.34%). This study provided an operable dynamic assessment model and available dynamic data for the global warming impact assessment of buildings in China.

Reflections on the Design of Urban Community and Residential Buildings in China in the Post-epidemic Era

The epidemic of COVID-19 is a public health emergency of international concern China cities have taken many measures to control the outbreak, which are timely and effective, but the problem and weaknesses in the urban planning stage have emerged At the urban level, a comprehensive disaster prevention planning for the dual situations of normality and epidemic should be concerned At the community level, the necessary improved facilities, the reasonable form, optimized spatial structure can support to construct a resilient community At the architectural level, it is necessary to conceive the variation of residential buildings and the flexibility of living space to respond to the changes in daily lives in the Post-epidemic Era © 2020 Festival Architettura Edizioni All rights reserved

Effect of climate zone change on energy consumption of office and residential buildings in China

Previous studies revealed that building climatic zoning has largely changed in China due to the influence of climate change. However, the possible impacts of changing building climatic zoning on energy consumption for cooling or heating are not clear. In this study, eight representative cities were selected from changed climate zones, and the heating and cooling energy consumption of office and residential buildings of the representative cities under the conditions of the current and new climate zones was simulated to reveal the effect of the climate zone change on building energy consumption. The results showed that there was no heating or cooling energy consumption with the climates changing from hot summer and cold winter (HSCW) and cold (C) to mild (M). Also, no heating energy consumption occurred with the climate zones changing from HSCM to hot summer and warm winter (HSWW), whereas the cooling energy consumption showed a weak decrease. For the climate zones that shifted from severe cold (SC) to C, decreasing heating energy consumption and increasing cooling energy consumption trends were observed, and the total energy use exhibited a decreasing trend. However, in the climate zones changing from C to HSCW, the heating and cooling energy consumption increased, especially for residential buildings (e.g., the heating energy consumption of Zhengzhou and Baoji increased 78.7% and 77.7%, respectively). This study suggests that new climate zones should be fully considered and the new design standard according to the changes of climate zones should be adopted to improve building energy efficiency. The design of residential buildings in the climate zones changing from C to HSCW may not consider the changes of climate zone.

Exploring key risks of energy retrofit of residential buildings in China with transaction cost considerations

Energy retrofit of residential buildings is an approach to reduce worldwide energy consumption. Residential energy retrofitting in China mostly focuses on multi-owner residential buildings with composite ownership that dozens of private homeowners own their apartment and jointly own the common parts of a building. The implementation of residential energy retrofit faces many risks, causing the slow retrofit process in the hot summer and cold winter (HSCW) zone of China. Transaction cost theory (TCT) is conducive to enrich an in-depth understanding of risk inventories in the energy retrofitting context. This paper aims to explore the key risks in retrofit projects of residential buildings in the HSCW zone with transaction costs (TCs) considerations, in order to provide the direction for effective risk management. First, based on the theoretical risks with TCs considerations, interviews were conducted to adjust the risk list and to connect these risks with stakeholders and stages. Second, a questionnaire survey was made based on two parameters of risk probability and severity, and then ten top risks were chosen as key risks through both a risk matrix and Borda count. The results show that most of the key risks are associated with homeowners and contractors, involving retrofit awareness, cooperation performance, opportunism, professional expertise, construction management, safety management, and maintenance, of which most occur at the stage of on-site construction. Information cost is the largest source of TCs relevant to these key risks and is mainly borne by the government and homeowners. TCs can also provide a lens for the retrofitting in other countries to understand risks, and the decrease in information costs contributes to effective risk management both in China and in the international context.

An adaptive predicted percentage dissatisfied model based on the air-conditioner turning-on behaviors in the residential buildings of China

To ease the Predicted Percentage of Dissatisfied (PPD) measurement and calculation and consider the adaptive behaviors of residents, the present research proposed an adaptive thermal discomfort evaluation model: Air-conditioner based Adaptive Predicted Percentage of Dissatisfied (aaPPD). First, the indoor temperature, outdoor temperature, and humidity data of the residential buildings in five cities within three climate regions in China were collected. Second, through the air-conditioner-turning-on (ATO) judgment algorithm, the data from when the air conditioner was turned on could be extracted from the original data, and then transformed via the Monte Carlo sampling method to obtain a dataset of the ATO percentage of residents within specific indoor and outdoor environments. Finally, a nonlinear model was built according to this dataset. The final R2 of this model was 0.833. This model utilized data from resident ATO behaviors as the basis for determining the thermal discomfort and avoiding the psychological impact on the subjects when filling out the thermal sensation vote questionnaire. Moreover, when compared with the PPD model, the aaPPD model simplified the variables to obtain the calculation parameters more conveniently and ease the thermal discomfort testing and predictions, which could allow for better adaptation to the early architectural design stage working characteristics.

Mitigating the Risks in Energy Retrofits of Residential Buildings in China

To speed up residential energy retrofitting in the Hot Summer and Cold Winter(HSCW) zone, the barriers to retrofitting projects need elimination. Energy retrofitting contributes to improving building quality and living comfort, but has not been accepted by the public. It stems from poor project performance in quality, time, costs, etc. The risk is an essential factor hindering such project objectives and project success. Residential energy retrofitting in China is exposed to various risks due to uncertainties regarding finance, organization, coordination, technology, etc. This thesis thus aims to deepen the understanding of risks in the whole process of residential energy retrofitting to smoothen its implementation and develop risk mitigation strategies for the HSCW climate zone of China. The thesis adopts Transaction Costs Theory (TCT) to identify the risks in the whole process of project implementation and assesses the importance of these risks in both objective and subjective aspects. Given the importance of homeowners-related risks and the key role of the government in retrofitting projects, this research develops s series of develop strategies for risk mitigation from the viewpoints of both homeowners and the government. The thesis contributes to the body of knowledge by conducting a systematic exploration of risks in retrofitting projects. In terms of the practical contributions, it does not only enable project managers to recognize the priority of project risks, but also help the government tackle these issues at its source for promotion of residential energy retrofitting.

Indoor Property Flood damage Assessment and Insurance for Residential Buildings based on HAZUS -- A case study of Mayangxi River Basin

The flood disaster is one of the most common natural disasters in China, and the indoor property loss of residents is huge every year due to the flood. Therefore, it is of great significance to study the evaluation of the indoor property flood loss of residential buildings. Based on HAZUS flood loss assessment method, this paper reclassifies the residential buildings in China according to the number of households. The post-disaster loss data and household income level were used to establish the depth-loss percentage function. It provides an important method for the rapid evaluation of the loss after disaster in this area. In order to transfer the risk of flood loss of indoor property of residents in Mayangxi River Basin, an insurance scheme is designed, which provides an important idea for disaster prevention and mitigation in similar areas.

Energy Sustainability of Rural Residential Buildings with Bio-Based Building Fabric in Northeast China

Due to the cold winters in northeast China, the energy consumption of the rural residential buildings is much higher in this region than in other regions. In this study, the energy sustainability of bio-based wall construction is examined through applications in rural residential buildings. Comparisons of the energy sustainability of the bio-based wall constructions and the conventional wall constructions are evaluated using IESVE-2019 computational simulation. The results show notable reductions in heating energy requirements and coal use, which is the major heating source for rural residential buildings in China. The results show that reductions of 45.82–204.07 kWh/m2/year in heating energy requirements and more than 40% in coal use are possible through application of bio-based wall constructions. The application of bio-based wall construction will result in lower seasonal air pollution and coal use through straw burning in northeast China.

Sustainable framework for buildings in cold regions of China considering life cycle cost and environmental impact as well as thermal comfort

In recent decades, environmental problems have enforced designers to estimate the level of environmental emission of building design and reduce their environmental impact. On the premise of ensuring indoor comfort, the cost-effectiveness of solutions for reducing the building’s greenhouse gas has become a critical issue. Based on the Life Cycle Assessment (LCA), this paper establishes a building performance trade-off framework for indoor thermal comfort, economics, and environmental implication. This framework consists of four parts: the establishment of the optimization model; sensitivity analysis; obtain of Pareto frontier solutions, and decision-making analysis. Optimization variables involve envelope type and some envelope physical parameters. The “design variables-building performances” database is obtained by using building simulation software combined with the Latin hypercube sampling algorithm. Sensitivity analysis is used to extract the key factors affecting building performance. The designer can prioritize these key factors and it can reduce the uncertainty of building performance. A multi-objective optimization method coupling Gradient Boosted Decision Tree (GBDT) and non-dominated sorting genetic (NSGA-II) algorithm is proposed to seek the trade-off between three performances (obtain Pareto frontier solutions). The Pareto solution provides a more comprehensive reference for the preferences of different stakeholders, and the set of alternative solutions is further shrunk. Finally, take a specific residential building in China’s cold climate zone as a showcase of the trade-off framework. According to the obtained Pareto frontier solution, the solution set is shrunk to a certain range, and the distribution ranges of Life Cycle Costs, the greenhouse gas emissions, and the annual thermal discomfort hour ratio are 122.3–137.1 USD/m2, 15.6–44.8 kg CO2/m2, and 19.1–25.2%, respectively. The trade-off framework adopts the order of objective Pareto optimal and then subjective preference selection, narrowing the scope of alternatives for designers and saving time-cost of decision-making.

Integrated Design of Solar Energy Utilization and Building Based on PLC

At present, fossil energy consumption still occupies a dominant position in China’s energy consumption structure, and problems such as low energy consumption efficiency, high degree of carbonization and large environmental pollution persist for a long time. Under the background of advocating environmental protection and energy saving, the combination of solar energy and building is the inevitable trend of building energy saving development, and the integrated design of solar energy and building has become a concern of the architectural circles. With the deepening of people’s understanding of environmental problems and the further deterioration of energy problems, more and more buildings begin to use clean and energy-saving solar energy devices. At present, the construction and development of urban residential buildings in China are mainly multi-storey and high-rise buildings. Therefore, higher requirements are put forward for the application form and scale of solar water heating system in residential buildings. In this paper, according to the current situation of solar energy utilization in buildings in China, based on PLC (programmable logic controller), the paper puts forward some suggestions to promote the integrated design of solar energy buildings.

The development and realisation of a multi-faceted system for green building planning: A case in Ningbo using the fuzzy analytical hierarchy process

After the Green Building Regulations in the Zhejiang Province was put into effect in May 2016, cities and prefectures in the province were given directives to set their own individual targets for the provision of green buildings. The city of Ningbo decided to use this opportunity to develop a systematic procedure, using Fuzzy Analytical Hierarchy Process (FAHP), to identify which allotments within the municipal area have the greatest potential of delivering green buildings, ensuring the set targets are fair and deliverable.This paper explains in detail the use of FAHP in the production of the Specific Plans for Green Buildings for the city of Ningbo in the Zhejiang Province of China. This innovative multi-faceted method incorporates the level of development in each of the 3213 land allotments in the municipal area, assessing each one for critical aspects such as environmental potential, local economic development land-use and land prices in order to determine an individual roadmap for the ratio of green buildings to be built in each region within the city. This method incorporates a scientific process, in which Pairwise Comparison Analysis was conducted for the selected criteria and aspects to determine the weighting factors and scores in each case. This allowed planners to rank all allotments in the municipal area in terms of their potential to provide green buildings, and thus make the setting of targets to provide these accordingly. This approach breaks away from the traditional method which relies on simple estimation, which is often unjustified. Over the two years since this method was introduced, the effects had been positive, within all the allotments abiding to the set targets. Other cities and regions in China, such as the provinces of Liaoning and Hebei, have also adopted this process.The Specific Plans for Green Buildings in Ningbo also include the adoption rate of prefabricated buildings and the mandatory date for when by which new residential buildings should be fully-furnished before they are sold (this is not currently the case in most residential buildings in China). These aspects are also discussed in this paper.

Case Study on Prefabricated Sunspace-Addition Renovation for Existing High-Rise Residential Buildings and Its Energy Consumption Simulations

A large number of existing high-rise residential buildings in China have problems such as high energy consumption and poor comfort. Renovating them is an important way for sustainable urban development. This article first introduces a European sunspace addition method for existing high-rise residences, and then sets up unit models of different depths for energy consumption simulation. Four cities of cold regions of China are selected and simulation comparison of original state, conventional renovation, sunspace addition and its variants are made. The size of the window, the presence or absence of external shading, and the presence or absence of internal curtains influence factors for the energy performance of the sunspace. In addition, the effects of changing depth of sunspace on winter heating energy consumption and summer cooling energy consumption, as well as the impact of different construction details on energy consumption were also studied. The article verifies the feasibility of the objective renovation mode in terms of energy consumption and summarizes the corresponding conclusions.

Power consumption and energy efficiency of VRF system based on large scale monitoring virtual sensors

Space cooling energy consumption is a significant component of building energy consumption, and in recent years it has attracted much attention worldwide owing to its significantly increasing usage. The variable refrigerant flow (VRF) system is one common type of cooling equipment for buildings in China and is applied extensively to residential and office buildings. The performance of VRF systems significantly influences the cooling energy consumption of buildings. The system energy efficiency and electricity consumption are the main indicators employed to evaluate the performance of VRF systems. It is hard to obtain the actual energy efficiency and electricity consumption of VRF systems in buildings because of the high cost of the required complicated measurements. This study proposes a virtual sensor modeling method to determine the actual energy efficiency and electricity consumption of 344 VRF systems in residential buildings. Statistical and clustering analyses are conducted to determine the energy efficiency and electricity consumption to obtain distributions and typical operation load patterns of VRF systems in residential buildings in China. The main findings are as follows: the main range of the Seasonal Energy Efficiency Ratio (SEER) for the cooling season is from 2.9 to 4.4; the median SEER in the Hot Summer and Cold Winter zone is lower than in another climate zones; the longer cooling duration may lead to greater electricity consumption, and the electricity load for VRF systems electricity load is periodic for each day. The oversizing issue is common for VRF systems in the dataset, which also led to the lower energy efficiency of VRF systems. The high usage of VRF systems appeared from July 27th to August 26th. The findings provide recommendations for designing VRF systems in residential buildings.

RESEARCH PROGRESS OF SHEAR WALLS: TYPES AND DESIGN METHODS

Reviews the development of shear walls in terms of their materials and section patterns in the recent decades. Because of the higher strength capacity, better seismic performance and possible architectural layout categories, the shear wall system has been increasingly applied to high-rise buildings and residential structures. Shear walls have experienced a long course of development from reinforced concrete, all steel to steel-concrete compositions. With the continuous innovation of materials and section types, shear walls are gradually developing towards high performance and prefabrication, which conform to the development needs of the residential buildings in China. This paper first focuses on the structural mechanism and design methods of various new steel corrugated plate shear walls and their experimental results under monotonic loads and horizontal cyclic loads. This paper also focuses on the structural mechanism and prefabrication process of concrete-infilled double steel corrugated-plate walls (CDSCWs). The research process, experimental results and design methods for the sectional strength capacity, overall stability, limb panel stability and seismic performance of CDSCWs are elaborated. Some key design formulas in the strength design are given. In addition, this paper introduces the scope and content of the “Technical Specification for Structures with Corrugated Steel Plate Components”, and briefly describes the design methods for special shaped concrete filled steel tubular columns (SSCFSTs) in the CDSCW-SSCFST frame structure system.

Life cycle carbon emissions of two residential buildings in China: Comparison and uncertainty analysis of different assessment methods

Life cycle assessment of building carbon emissions has drawn great attention recently, due to the policy of controlling the greenhouse effect. Various approaches including process-based method, input-output analysis, and hybrid method have been applied for the assessment. Hence, with the purpose of achieving a comprehensive comparison of these approaches, the present study made a comparative analysis in light of the uncertainties in parameter, scenario, and modeling. Based on the life cycle assessment of two residential buildings, both deterministic and stochastic analyses were conducted to quantify the differences and relevant uncertainties in the emissions by different assessment methods. The results indicated that the choice of methods had significant influences on the calculated emissions, which ranged from 3.3 to 3.6 tCO2e per floor area for the two buildings. With consideration of the parameter uncertainty, pure input-output analysis could lead to considerable errors, and hybrid methods were recommended in the emission assessment. Furthermore, based on the analysis of defined scenarios, scenario and model uncertainties were evaluated and compared for different assessment methods. Overall, the findings and suggestions could be helpful for understanding the differences and uncertainties in the results of carbon emission assessment, and therefore benefit the quantification of building emissions.

Study on the impact of window shades’ physical characteristics and opening modes on air conditioning energy consumption in China

• A shading schedule of residential buildings is obtained through 949 questionnaires. • Two opening modes of window shades were considered. • Analyzed the six physical characteristics of window shades on energy consumption. • The results could allow design guidelines for developing the performance of window shades. This paper focused on the impact of window shades’ physical characteristics and opening modes on annual air conditioning energy consumption of residential buildings in China. Three building models with different window layouts were proposed initially, and then validated by the dimensionless indicator annual energy performance (AEP) to determine the final building model adopted in this study. Harbin, Beijing, Guangzhou, Changsha and Kunming were selected to represent five different climate zones in China. The shading model has taken six physical characteristics of window shades, viz. outer emissivity, inner emissivity, solar transmittance, solar reflectance, thermal infrared transmittance, conductivity and two opening modes, viz. up & down mode as well as left & right mode, into consideration. Besides, the window shades operation schedule was summarized through 949 valid questionnaires. The annual air conditioning energy consumption was calculated via EnergyPlus software, and then the impact of the above different opening modes and parameters on energy use were investigated. The analysis results indicated that the top & bottom opening mode is better than the left & right mode when used in Harbin, and the effect of two different modes in air conditioning energy consumption in Kunming is similar. But in the other three cities, the left and right mode is preferred. Besides, the analysis results of the impact of different physical characteristics on air conditioning energy use in different climate zones could help improve the energy performance of window shades.

The typical hot year and typical cold year for modeling extreme events impacts on indoor environment: A generation method and case study

Increasing climate change brings not only global warming, but also more frequent and severe extreme events, which greatly affect the indoor environment. There has been some research discussing the impacts of extreme events on indoor thermal environment, mostly related to heatwaves, but quite limited on extremely cold events which occurred in recent years. In this study, the indoor environment was simulated in a typical residential building in China’s hot summer and cold winter climate zone, that has faced both kinds of events, using ERA5 database (reanalysis weather data) in the past 40 years. The simulation results were analyzed for a better understanding of the indoor events of extreme hot or cold conditions and were used to select the weather data for modelling extreme event impacts, including a typical hot year and typical cold year defined in this study. The impacts of the indicator were used to evaluate overheat or extreme cold conditions, and the building envelope level were also discussed.

Evaluation of thermal imbalance of ground source heat pump systems in residential buildings in China

The thermal comfort level of Chinese residents in the hot-summer and cold-winter zone is increasing with economic development in recent years. More district heating and cooling systems were installed in these areas. Supported by the government, ground source heat pump (GSHP) is used as a common environmentally friendly district heating and cooling system in many residential communities. However, the evaluation of the real performance of GSHP is limited, especially limited understanding of the common issue of thermal imbalance of GSHP systems over several years—the mismatch between heat extraction from and rejection to the ground. Performance of GSHP systems can deteriorate over years if the thermal imbalance is significant and not addressed. For GSHP in the hot-summer and cold-winter climate zone, there are few thermal imbalance studies based on real field data and modeling. To address this gap, this paper proposes an integrated simulation model to evaluate thermal imbalance of GSHP systems considering key influencing factors including occupant behavior and heat pump performance. A case study was conducted to simulate and analyze the actual operation of GSHP in Chinese residential buildings. The indoor comfort temperature setting and flexibility of residents’ control on indoor terminal air-conditioning units determine the actual heating and cooling demand in residential buildings, which resulted in differences in thermal imbalance for GSHP systems. It was found that GSHP systems with radiant floor only for heating lead to the most severe thermal imbalance, while GSHP systems with fan coil units or radiant ceiling for cooling and/or heating achieved much better thermal balance. The proposed thermal imbalance ratio is an important indicator that can be used to evaluate thermal imbalance of GSHP systems and thus inform their design and operation for energy efficiency.