Operation optimization strategy of existing residential building energy-saving renovation market:From the perspective of subject behavior

The energy-saving renovation of existing residential buildings is a crucial measure to achieve the strategic goal of energy conservation and emission reduction in China and build ecologically livable cities.This article focuses on the perspective of subject behavior,starting from analyzing the current situation and difficulties of the operation of the energy-saving renovation market for existing residential buildings in China,drawing on the practical experience of the operation of the existing residential building energy-saving renovation market abroad.Based on principles such as systematicity,humanization,feasibility,and sustainability,the article constructs an operation optimization system of the existing residential building energy-saving renovation market from the perspective of subject behavior.In order to provide a reference for the healthy and orderly operation of the existing residential building energy-saving renovation market,this paper proposes implementation strategies for optimizing the operation of the existing residential building energy-saving renovation market.Suggestions are proposed from four aspects:optimizing the market environment,innovating the financing model,building the information sharing platform,and utilizing the synergies of the main subjects.

Multi-subject and multi-objective integrated optimization system and implementation strategy for energy-saving renovation of the existing residential buildings

The core of the healthy and orderly operation of the existing residential building energy-saving renovation market lies in the exploration of the implementation mechanism of multi-subject and multi-objective integrated optimization.The multi-agent and multi-objective integrated optimization system framework is a powerful tool to guide the scientific decision-making of the market core structural entities in the future market practice. This paper analyzes the practical dilemma of energy-saving renovation of theexisting residential buildings in China, summarizes the practical experience of multi-subject and multi-objective integrated optimization of energy-saving renovation of the existing residential buildings in foreign countries, and puts forward beneficial practical enlightenment on the basis of comparison at home and abroad;The design principles of the target integrated optimization system have established a multi-subject and multi-objective integrated optimization system framework for the energy-saving renovation of the existing residential buildings, from six aspects: government guidance, trust consensus, value co-creation, risk sharing, revenue sharing, and social responsibility sharing. This paper proposes a multi-subject and multi-objective integrated practice strategy, in order to promote the efficient and orderly development of China's existing residential building energy-saving renovation market.

Research on the Spatial Characteristics of Traditional Residential Buildings in Ningxia Region

This article takes traditional residential buildings in Ningxia region as the starting point,and through field research and data analysis,demonstrates the specific elements of the spatial composition of traditional residential buildings and the common forms of courtyard space.The study summarizes the regional cultural characteristics of traditional residential buildings in the region,laying a foundation for subsequent research and providing some reference basis.

Benchmarking of energy efficiency standards for residential buildings in China

In order to benchmark the energy efficiency standards for residential buildings in China,the Hong Kong building environment assessment method（HK-BEAM）is chosen as the compliance criteria for assessment.The annual energy consumption and the overall thermal transfer value（OTTV）of a baseline residential building prescribed in the Chinese codes and the HK-BEAM are evaluated and compared by the energy budget approach.The results show that in the Chinese codes,the OTTV of the residential building is lower,but the annual energy consumption and the cooling load are higher than those in the HK-BEAM.The annual energy use difference amounts to 13.4%.All the compliance criteria except the ventilation rate and the equipment power in the Chinese codes are set higher than those in the HK-BEAM.However,the compliance criteria of the ventilation rate and the equipment power,especially the ventilation rate,result in much energy consumption,which ultimately induces a high energy budget for residential buildings.

Assessing the adequacy and sustainability performance of multi-family residential buildings in Anambra State,Nigeria

The proliferation of multi-family residential building in Anambra State of Nigeria due to increasing demand without recourse to performance has broughtconcerns about the adequacy and sustainability of this housing type.This study therefore,assessed the adequacy and sustainability performance of multi-family residential buildings in urban areas of Anambra State.The study sampled the opinions of 384 households living in multi-family residential buildings through a questionnaire survey.We conducted data analysis based on 214 responses that were useful for analysis.The study found that internal and building component variables and supporting neigh-borhood variables were adequate,but the surrounding environment variables were inadequate based on Mean Score Index.However,based on Sustainability Performance Index,the occupant sperceived social sustainability performance of the buildings as satisfactory,while environmental and economic sustainability performance were perceived as fairly satisfactory.The Pearson correlation coefficient result further established that adequacy of internal and building component variables was significantly and positively related to the residents'perceived social sustainability performance.Adequacy of the surrounding environmental variables was also found to be positively and significantly related to the residents'perceived environmental sustainability performance,whereas adequacy of supporting neighborhood facilities was found to be negatively and significantly related to the residents’perceived economic sustainability performance.This sug-gested that investors and owners of multi-family residential buildings should direct more efforts towards improving the surrounding environment to supplements other facilities and increase the economic benefit of the renters or occupiers with increasing economic sustainability performance in terms of value for money.

Analyses of influence of residential buildings' space organization on heating energy consumption in Lhasa

The heating load simulation models of the residential buildings in Lhasa are established for enhancing the space organization’s adaptability to climate and radiation and improving its energy saving performance.The space organization items a e analyzed for both the existing buildings without insulation and new buildings with good insulation.The items include orientation design,south a d north balcony design,the north and south partition wall’s position design,storey height design and window-wall ratio design.Simulation results show that orientation is the key design element for energy saving design,and adverse orientation can obviouslyincrease heating energy consumption;south and north balconies can reduce winter heating energy consumption;partition walls move to the north,which means that the south room’s big depth design leads to less heating energy consumption,but the effect is not inconspicuous;smaier storey height results in less heating load.For the existing buildings,the window-wall ratio of south side has a balance point for energy saving design in the calculation condition.For the new buildings with good insulation,enlarging the south window-wal ratio can continuously reduce heating energy consumption,but the energy saving rate between models gets smaier.The heating energy consumption comparison study between the common model and optimal space design model demonstrates that the energy saving design can significantly reduce heating energy consumption

Demand Flexibility of Residential Buildings:Definitions,Flexible Loads,and Quantification Methods

This paper reviews recent research on the demand flexibility of residential buildings in regard to definitions,flexible loads,and quantification methods.A systematic distinction of the terminology is made,including the demand flexibility,operation flexibility,and energy flexibility of buildings.A comprehensive definition of building demand flexibility is proposed based on an analysis of the existing definitions.Moreover,the flexibility capabilities and operation characteristics of the main residential flexible loads are summarized and compared.Models and evaluation indicators to quantify the flexibility of these flexible loads are reviewed and summarized.Current research gaps and challenges are identified and analyzed as well.The results indicate that previous studies have focused on the flexibility of central air conditioning,electric water heaters,wet appliances,refrigerators,and lighting,where the proportion of studies focusing on each of these subjects is 36.7%,25.7%,14.7%,9.2%,and 8.3%,respectively.These flexible loads are different in running modes,usage frequencies,seasons,and capabilities for shedding,shifting,and modulation,while their response characteristics are not yet clear.Furthermore,recommendations are given for the application of white-,black-,and grey-box models for modeling flexible loads in different situations.Numerous static flexibility evaluation indicators that are based on the aspects of power,temporality,energy,efficiency,economics,and the environment have been proposed in previous publications,but a consensus and standardized evaluation framework is lacking.This review can help readers better understand building demand flexibility and learn about the characteristics of different residential flexible loads,while also providing suggestions for future research on the modeling techniques and evaluation metrics of residential building demand flexibility.

Field study of seasonal thermal comfort and adaptive behavior for occupants in residential buildings of Xi’an,China

The study aims to investigate the thermal comfort requirements in residential buildings and to establish an adaptive thermal comfort model in the cold zone of China.A year-long field study was conducted in residential buildings in Xi’an,China.A total of 2069 valid questionnaires,along with indoor environmental parameters were obtained.The results indicated occupants’thermal comfort requirements varied with seasons.The neutral temperatures were 17.9,26.1(highest),25.2,and 17.4℃(lowest),and preferred temperatures were 23.2,25.6(highest),24.8,and 22.4℃(lowest),respectively for spring,summer,autumn,and winter.The neutral temperature and preferred temperature in autumn are close to the neutral temperature in summer,while the neutral temperature and preferred temperature in spring are close to that in winter.Besides,the 80%and 90%acceptable temperature ranges,adaptive thermal comfort models,and thermal comfort zones for each season were established.Human’s adaptability is related to his/her thermal experience of the current season and the previous season.Therefore,compared with the traditional year-round adaptive thermal comfort model,seasonal models can better reflect seasonal variations of human adaptation.This study provides fundamental knowledge of the thermal comfort demand for people in this region.

Study on Dominant Expression of Regional Culture of the Qinling Mountains in Local Residential Buildings

Regional culture of the Qinling Mountains shows distinct features since it was born in the local outstanding ecological environment, study on local architecture is significant for the dominant expression of regional culture, protection of local environment, and echoing with the theme of ecological civilization construction. This paper, on the basis of the mutual infl uence and evolution of regional culture and style of local residential buildings, explored the reasons for the weakening of local architectural style, and specified the signifi cance of promoting local style of the living environment. By studying the infl uence of local natural environment and humanistic environment on architectural style along the northern foot of the Qinling Mountains, the paper explored the expression of regional culture in residential buildings, with Xian Garden(Xi'an Yuanzi) as an example, and aimed at giving useful help to the dominant expression of regional culture in modern residential buildings.

Test and Analysis of Indoor Thermal Environment of Urban Heating Residential Building in Hanzhong Area

By testing indoor and outdoor thermal environment of residential buildings that apply 4 mostused heating ways in Hantai District,Hanzhong City,this paper explored the indoor thermal environment conditions of different heating ways,to provide references for choosing a suitable heating way in the local area.

Design of Low Carbon and Energy-saving New Rural Residential Buildings in Western Parts of Heilongjiang Province

It is researched that rural residential buildings in Heilongjieng consume high energy and the living environment is poor. The research aimed at designing low-carbon and energy-saving buildings in order to reduce energy consumption by applying energy storage. Besides, the research used composite solar panel, waste- based inorganic foam materials, and polystyrene board as construction materials and integrated energy collection, living environment and farming by energy storage system. It is notable that the research would reduce pollution on environment caused by residential buildings, which coincides with national economy development and en- ergy strategy, promoting construction material industry development, with high social and economic benefits.

Defects in Concrete Elements: A Study of Residential Buildings of 30 Years and above in Onitsha Metropolis, Anambra State, Nigeria

Building defect is an issue in existing buildings that needs urgent tackling to prevent further problems. This study assessed the defects in concrete elements in residential buildings of 30 years and above in the Onitsha metropolis of Anambra State, Nigeria. Data collection instruments in the study include structured questionnaire, interviews, visual inspection/observations, archival records, recordings, photographs;and non-destructive testing of the concrete elements in an existing building in the study area. The population of this study constituted of the construction registered professionals and the existing buildings in study area. The sample for the study was based on the calculated sample size using Taro Yamani Formula. A total of 158 registered professionals were sampled from the population of 260. The questionnaires were purposively distributed to the registered professionals up to the required sample sizes of 158 and 129 questionnaires were properly filled and returned. The study used the SPSS and Microsoft Excel to analyze the data. The results were analyzed in percentages and figures using descriptive statistics and presented in the form of pie charts and tables. The finding of the study revealed that the causes and effects of structural defects on the concrete elements in existing buildings in the study area according to the rating are;exposed/corrosion of the embedded metals, faulty workmanship, overload and impacts, chemical attack, freeze-thaw deterioration, fire/heat, restraint to volume change. The visual observation revealed that the structural elements are characterized by heavy defects such as deep vertical, horizontal and diagonal cracks, exposed/ corrosion of the embedded metals, spalling of the concrete slabs. The existence of defects in the concrete members led to the low compressive strength of the concrete elements and the structural instability of the existing buildings as revealed by the non-destructive test. The non-destructive test result revealed that most of the tested concrete elements have low compressive strength value and such were remarked poor as they did not satisfy the assumed value. Essentially, the study concluded by recommending that regular monitoring, inspections and non-destructive testing of concrete elements should be conducted on existing aged and defected buildings to detect the structural stability of the buildings;and it is imperative to evacuate occupants from heavy structurally deteriorated and defected buildings since most of them have lost their residual design life span and ability to sustain imposed loads.

The Impacts of Building Regulations on the Thermal Performance and Energy Consumption of Residential Buildings in Riyadh City-Saudi Arabia

Riyadh city is the fastest growing city in Saudi Arabia. The rapid urban growth that happened recently in Riyadh was not based on the traditional urban planning principles, which have been established and applied for the city development process. The imported building regulations have created a new urban structures and street patterns. The contemporary urban form in Riyadh city is based mainly on traffic and economic consideration with the neglect of environmental dimensions. This research aims to examine the impacts of building regulations on the thermal performance of residential buildings in Riyadh city, with the ultimate goal of establishing planning guidelines that consider the environmental conditions of the city. The methodology adopted for achieving the aim of this study consists of two phases. First, the literature related to building regulations development in Riyadh, as of 2018, was reviewed. Second, buildings energy simulation was conducted to examine the thermal performance of the typical current status of residential building blocks in Riyadh city, and then several changes to building regulations were made to investigate their impacts on the thermal performance of buildings. The results showed that the impacts of Riyadh building regulations on the thermal performance of residential buildings differ across the evaluated cases. The ratio of building height to street width, urban block street orientation, and building orientation are the main factors affecting thermal performance of buildings within urban block. The study also concludes that adjusting the ratio of building height to the distance between buildings could have a significant impact in reducing cooling loads. This study will help policy makers, planners and designers to investigate the shortcoming in the current building regulations.

Evaluating Economic and Environmental Benefits of Integrating Solar Photovoltaics within Future Residential Buildings in Saudi Arabia

Renewable energy options, including solar power, are becoming increasingly viable alternatives to conventional sources of energy, such as oil, coal and natural gas. Solar Photovoltaic （PV） technology is one type of solar energy technologies that has recently received substantial attention because it offers the possibility of providing clean power sources for buildings. The aim of this paper is to examine the economic viability of using solar PV within future residential buildings in the oil-rich Saudi Arabia. Strictly speaking, the prospects of using the PV in order to provide 10% of the electricity to be consumed in the houses, which are going to be built in Sandi Arabia over the period 2010-2025, are examined. The study reveals that significant economic and environmental benefits could be realized as a result of such an endeavor.

What decarbonized the residential building operation worldwide since the 2000s

Decarbonization in operational residential buildings worldwide has become critical in achieving the carbon neutral target due to the growing household energy demand.To accelerate the pace of global carbon neutrality,this study explores the operational carbon change in global residential buildings through the generalized Divisia index method and decoupling analysis,considering the decarbonization levels of residential buildings at different scales.The results show that(1)most of the samples showed a decrease in the total emissions from 2000 to 2019.Except for China and the United States(US),the carbon emissions in global residential building operations decreased by 7.95 million tons of carbon dioxide(MtCO_(2))per year over the study period.Emissions per gross domestic product(GDP)was the most positive driver causing the decarbonization of residential buildings,while GDP was the most negative driver.(2)Carbon intensity was essential to achieving a strong decoupling of economic development and carbon emissions.The US almost consistently presented strong decoupling,while China showed weak decoupling over the last two decades.(3)The pace of decarbonization in global residential building operations is gradually slowing down.From 2000 to 2019,decarbonization from residential buildings across 30 countries was 2094.3 MtCO_(2),with a decarbonization efficiency of 3.4%.Overall,this study addresses gaps in evaluating global decarbonization from operational residential buildings and provides a reference for evaluating building decarbonization by other emitters.

Lectotype optimization of mid-highrise residential building based on site conditions and seismic fortification intensity

A multi-objective lectotype optimization model based on site conditions and seismic fortification intensity is presented for mid-highrise residential buildings taking into account multiple items such as the original investment, disaster losses and maintenance cost, the integral stiffness, the total ductility, the construction period, and so on. A Three-Scale Fuzzy Analytical Hierarchy process is proposed by introducing the Three-Scale Analytical Hierarchy process and the trapezoid fuzzy number. The result of a calculation example shows that the T-FAHP is practical.

Indicator system of energy efficient technologies evaluation of residential buildings in hot summer and cold winter regions of China

The related existing energy saving index system of buildings is deficient in direction, index coverage, depth, and technological and economic considerations. Aiming at the deficient existing research and with the advancement of energy saving of buildings in China from northern heating regions to southern hot summer and cold winter regions, selecting residential buildings in hot summer and cold winter regions as the research object, and through much evaluation index reference and repeated demonstrations and the borrowing of literature research home and abroad and relevant energy saving standards, filters and eliminates energy efficient technologies evaluation indexes according to the design principle of index system, the factors influencing the energy saving of residential buildings are evaluated, index system weight is established by adopting analytic hierarchy process, and finally the evaluation index system of energy saving technologies of residential buildings in hot summer and cold winter area of China is established. Each target layer includes five standard layer indexes and sixteen index layer indexes. The standard layer of evaluation index, namely primary indexes, includes the technological, energy saving effect, economic, environmental, and social indexes. The secondary indexes are selected based on the principles of concision, comprehensiveness, representativeness and operability.

Passive Cooling Strategies in Greening Existing Residential Building in Hot Dry Climate： Case Study in Bahrain

This paper will present several passive-cooling technologies and design features that can be adopted to reduce building heat gain without the need of excess energy consumption. A typical residential unit will be selected as case study and a three basic passive cooling strategies were selected to enhance the building envelop, as well as using appropriate shading devices and green roofing system that prove to be a good environment quality improver. IES energy simulation software will be used to evaluate the performance of the building. The study revealed a number of significant findings in reducing the energy consumption and enhancing the tenants＇ thermal comfort. American Society of Heating Refrigerating and Airconditioning Engineer （ASHRAE） standards specially via improving the performance of building envelop because it is the interface between internal and external environment. Moreover, improving the building envelope has recorded that overall energy and chiller energy consumption can be reduced up to 10.8% and 21.6% respectively, Therefore, it is anticipated that further reductions can be achieved via applying more passive cooling strategies. Finally, it could argue that the results of this paper will not only be applicable to Bahrain but also many countries that have similar climatic and environmental context.

Energy-saving Planning and Design of Urban Residential Buildings in Hanzhong Area

Energy-saving design of residential building is an important part of energy-saving architectural design. Planning and design of residential buildings in Hanzhong area should pay more attention to the building orientation, sunshine, summer ventilation and wind resistance in winter and so on, so as to create favorable conditions for energy-saving design of single buildings. The geographical location, climatic characteristics, residents living habits and indoor and outdoor thermal environment situation were analyzed in this paper, and combined with the existing problems of energy conservation in the planning and layout of residential buildings in Hanzhong area. Based on the investigation, this paper drew some conclusions to provide references for the energy-saving planning and design of urban residential buildings in the local area.

Windows Influence on Room Daylighting in Residential Buildings

Daylighting studies in buildings are key parts of environmental analysis and can be easily conducted at the early stages of design as part of environmentally responsive building design as well as to inform the final architectural layout and interior design. The main aim of this study is to demonstrate how such daylighting studies can be completed at the early stages of design and, at the same time, to show the impact of window design and positioning on building indoor environments. The paper is focused on a study of window influence on room daylighting in residential buildings and computer lighting simulations in software packages： Windows Daylighting System and Autodesk Ecotect Analysis, have been carried out for different style and positioning of windows using several case studies. The main findings clearly indicated that not only the window size and style matters, but also the positioning of windows considering external walls which would make a significant influence on room daylighting levels and, therefore, such daylight studies are very important for the early stage of environmental analysis during building design.