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.

Development of Temperature-Humidity Independent Control Air-Conditioning Unit for Residential Buildings

Cooling panels are increasingly used in domestic residential buildings.To provide medium temperature cold water for the cooling panel,and dehumidify the indoor air simultaneously,a new kind of temperature-humidity independent control air-conditioning unit was developed for single residential house by utilizing multi-variable technology.First,the supply air temperature was studied to determine the proper supply air flow rate for the humidity control.Then,the energy consumption of different temperature-humidity independent control systems was studied.The analysis indicates that unity evaporating temperature can be used to handle the moisture load and sensible heat load in two evaporators.So the unit scheme was put forward.Two evaporators were used to produce medium temperature water and dry air separately,and electric expansion valves were used to control the refrigerant distribution between the two evaporators.Then,experimental work was carried out to investigate the influence of compressor frequency,refrigerant distribution on the dehumidification capacity,energy efficiency and refrigeration capacity.In the end,the paper concludes that both compressor frequency and refrigerant distribution can control the dehumidification capacity,but the former influences the EER more than the latter,while the latter influences the refrigeration capacity more than the former.We can find a proper running point at certain sensible and latent cooling load by adjusting both compressor frequency and electric expansion valve.The energy consumption of this kind of unit was estimated and compared with present room air conditioners,which shows that it can save about 41% cooling energy consumption.

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.

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.

Energy Consumption Monitoring Analysis for Residential, Educational and Public Buildings

In the present article thermal and electrical energy consumptions for different types of buildings are analyzed. The latitude and longitude of the researched area are defined 59?00'N and 26?00'E. According to K?ppen climate classification the area is located in warm summer continental climate. The study consist 40 residential, 7 educational and 44 public buildings. Three years data for each building type among 2006-2011 was used. Several detailed energy balances are presented for apartment buildings. In addition the different ways of domestic hot water preparation are analyzed for apartment buildings. The school buildings average consumption values are represented in study. Also valuable information of measured electrical energy consumption balance for a new office building is presented. Finally there is included the energy consumption analysis of public buildings.

Thermal adaptation in overheated residential buildings in severe cold area in China

The winter in the severe cold area of China is long and cold. The mean outdoor temperature is about-10. 0 ℃ during the winter in Harbin,while the indoor air temperature is often above24 ℃. How does the indoor environment influence human thermal comfort and adaptation in such an overheated environment?A combined approach of spot-reading measurements and occupant interview s w as adopted in nine residential buildings of five communities during the heating period in 2013-2014. Tw enty residents w ere chosen as respondents. Totally 308 valid questionnaires w ere collected. The heating periods w ere separated into three phases based on the outdoor temperature.The results show that the mean indoor air temperatures in theearly-,mid-and late-heating periods w ere 23. 6 ℃,24. 3 ℃and 25. 0 ℃,respectively,w hich w ere larger than or close to the upper limit recommended by thermal comfort standards, and slightly higher than the related thermal neutral temperatures. With the heating process,the mean clothing insulation of residents decreased. Opening w indow s and reducing clothing w ere mainly taken by the residents to adapt to the overheated environment.The thermal neutral temperature has an upw ard tendency w ith the increasing indoor air temperature. On the other hand,overheating in residential buildings w ould make residents open w indow s,w hich may cause thermal discomfort and energy w aste. Therefore,the low er limit of the comfort indoor air temperature range should be suggested as the heating temperature,w hich could fully arouse residents' adaptation and achieve sustainable building designs.

Characteristics of Changes in Energy Consumption of Rural Residential Buildings from the Perspective of Province and Recommendations

In the context of the new period,the living standards and comfort demands of rural residents are increasing,which promotes the continuous growth of the total energy consumption of rural residential buildings.In this study,it estimated the total energy consumption of rural residential buildings in 30 provinces(or cities)in China from 2004 to 2016.Through the division of climate regions of the residential buildings,this paper analyzed the characteristics of changes in the energy structure of residential buildings and the trend of energy consumption from the perspective of the province.Then based on the people s livelihood and from the perspective of development,it came up with some pertinent strategies and recommendations for energy saving and emission reduction in rural residential buildings.

Application of natural ventilation of residential buildings in hot-humid regions

The current ventilation condition of the hot and humid regions was analyzed through on-site investigation. It is found that residents in this region expect to improve indoor thermal environment through natural ventilation as much as possible. Then,it comes to a conclusion by the field test that natural ventilation has certain practical effect on improving indoor thermal environment. CFD simulation software is employed to verify the test result. Based on PMV modified model,and according to norms,geography and climate combined with the measured and simulated results,the application of the time and effectiveness of natural ventilation in hot and humid region were analyzed,to some extent,providing a basis for reducing the air-conditioner's runtime with natural ventilation.

Ventilation of air-conditioned residential buildings: A case study in Hong Kong

More and more studies reported that there were insufficient ventilation and excessive CO_2 concentration in air-conditioned residential buildings, but few solutions were provided. This study investigates the overnight evolution of CO_2 concentration in air-conditioned residential buildings and then focuses mainly on the evaluation of three ventilation strategies, including overnight natural ventilation, short-term mechanical ventilation and short-term natural ventilation. On-site measurements were conducted in a typical residential bedroom in Hong Kong in September. The indoor and outdoor CO_2 concentration, air temperature and relative humidity as well as the outdoor wind speed during the measurements were analysed. Ventilation rates were calculated based on the time series of CO_2 concentration. This study confirms that additional ventilation is usually needed in air-conditioned residential buildings. Overnight natural ventilation with even a small opening is associated with excessive energy consumption and deteriorated indoor thermal environment. Short-term natural ventilation strategies are inefficient and uncontrollable. Compared to the best short-term natural ventilation strategy, a reasonably designed short-term mechanical ventilation strategy requires only a 41% of ventilation period to complete one full replacement of indoor air and to reach a lower indoor CO_2 concentration. Nighttime case studies and a theoretical analysis suggest that a few several-minute mechanical ventilation periods could potentially maintain an acceptable indoor air quality for a normal sleeping period of 8 h.

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.

Indoor Environmental Quality of Air Conditioned Residential Buildings in Extreme Dry Desert Climate

In this study, the indoor environmental quality (IEQ) in air conditioned residential buildings in a dry desert climate is examined from the perspective of occupants via two aspects: thermal comfort and indoor air quality. The study presents statistical data about the domestic-occupant thermal comfort sensations together with data describing the indoor air quality in Kuwaiti residential buildings. With respect to the latter, the overall IEQ acceptance using two measurements namely: physical measurements and subjective information collected via questionnaires, was used to evaluate 111 occupants living in twenty five air-conditioned residential buildings in the state of Kuwait. The operative temperature based on Actual Mean Vote (AMV) and Predicted Mean Vote (PMV) was identified using linear regression analysis of responses on the ASHRAE seven-point thermal sensation scale and was found to be 25.2°C and 23.3°C, respectively, in the summer season. Indoor air quality (IAQ) with respect to carbon dioxide concentration level was compared with the acceptable limits of international standards, i.e. ASHRAE Standard 62.1 [1]. The proposed overall IEQ acceptance findings in residential buildings show CO2 concentration level between 909 and 1250 ppm. However, this may be considered a higher level of CO2 concentration, which may require increasing ventilation rate through window operation or mechanical ventilation.

The Effects of Future Climate Change on Energy Consumption in Residential Buildings in China

China is currently going through a phase of rapid mass urbanisation, and it is important to investigate how the growing built environment will cope with climate change, to see how the energy consumption of buildings in China will be affected. This is especially important for the fast-growing cities in the north, and around the east and south coasts. This paper aims to study the effects of future climate change on the energy consumption of buildings in the three main climate regions of China, namely the “Cold” region in the north, which includes Beijing;the “Hot Summer Cold Winter” region in the east, which includes cities such as Shanghai and Ningbo;and the “Hot Summer Mild Winter” region in the south, which includes Guangzhou. Using data from the climate model, HadCM3, Test Reference Years are generated for the 2020s, 2050s and 2080s, for various IPCC future scenarios. These are then used to access the energy performance of typical existing buildings, and also the effects of retrofitting them to the standard of the current building codes. It was found that although there are reductions in energy consumption for heating and cooling with retrofitting existing residential buildings to the current standard, the actual effects are very small compared with the extra energy consumption that comes as a result of future climate change. This is especially true for Guangzhou, which currently have very little heating load, so there is little benefit of the reduction in heating demand from climate change. The effects of retrofitting in Beijing are also limited, and only in Ningbo was the effect of retrofitting able to nullify the effects of climate change up to 2020s. More improvements in building standards in all three regions are required to significantly reduce the effects of future climate change, especially to beyond 2020s.

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.

Research on Evaluation System of Green Residential Buildings in Cold Areas of Sichuan

With regard to the rapid growth of China’s building area and the increasing energy consumption of buildings, green buildings have become an important issue for balancing economic development and environmental impact. However, the current evaluation systems for various types of green buildings are often unable to achieve a set of standards in practice due to the distinct regional characteristics of each region. Therefore, in view of the regional characteristics of the climate, terrain, ecology, and economic development in the cold regions of Sichuan, it is important to study the evaluation system of green residential buildings suitable for the cold regions of Sichuan. This article focuses on the regional characteristics of climate, topography, ecology, and economic development in the cold regions of Sichuan, and discusses the limitations of the current standards on the practice of green building in cold regions of Sichuan through a sociological questionnaire survey on the comfort of living in the local population. Then from the two dimensions of the advantages of traditional houses and the particularity of national culture, the strategies for the optimization and improvement of the evaluation index system for green residential buildings in the cold regions of Sichuan were proposed. After comprehensively considering the factors that affect the green residential buildings, including the regional characteristics of the cold regions of Sichuan, and the green performance of buildings, local characteristics and ethnic features were included in the evaluation system. The evaluation index system of green residential buildings in the cold regions of Sichuan, consists of 92 three-level indicators. A professional hierarchical analysis software yaahp was used to establish a multi-level hierarchical model between the indicators, and the indicators were compared with each other layer by layer to clarify the importance of the indicators. Based on this, a judgment matrix for each layer was constructed and obtained. The weight of each indicator is accurate, and the scoring mechanism and grading standards are constructed according to it. Through the calculation, the consistency test of the entire model was passed, thereby confirming the scientificity and rationality of the entire evaluation system.

The Elegance of Hui-Style Residential Buildings

Hui-style residential buildings are an important genre of traditional Chinese architecture,mainly found in Jixi and Wuyuan counties of Anhui Province,Chun’an County of Zhejiang Province,and Fuliang County of Jiangxi Province.This kind of residential architecture is characterized by white walls,black tiles,and exquisite carvings,all of which retain the elegant and rustic charm of more than 600-year-old Anhui communities.

Use of Renewable Energies for the Creation of Net Zero Carbon Emission Residential Buildings in Northern Greece

The necessity to cope with the global threats of climate change has increased our concern on the energy sources used increasing the share of renewable energies and shifting from fossil fuels to benign energy sources. European Union through various directives aims at increasing sustainability in buildings reducing their energy consumption, fossil fuels use and carbon emissions. In this context, the use of renewable energies covering all the energy needs and zeroing the carbon footprint in a residential building located in northern Greece has been investigated. Use of locally available sustainable energies including solar energy, solid biomass and waste heat rejected from power plants has been proposed for covering all the energy needs in a house. Their technologies for heat and power generation are mature, reliable and cost effective. Results have indicated that the combined use of the abovementioned sustainable energies can cover all the energy needs in the building, zeroing its carbon emissions due to operating energy use. The investment cost for a house at 150 m2 varies between 6200 € to 10,700 € or 41.33 to 71.33 € per m2 of the building covered surface, which is relatively low compared with its construction cost. Therefore, the creation of zero CO2 emissions residential buildings due to energy use in northern Greece is technically and economically feasible.

Life Cycle Energy of Low Rise Residential Buildings in Indian Context

Life cycle energy of the building accounts for all energy inputs to the buildings during their intended service life. Buildings need to be constructed in such a way that energy consumption in their life cycle is minimal. Life Cycle Energy (LCE) consumption data of buildings is not available in public domain which is essentially required for building designers and policy makers to formulate strategies for reduction in LCE of buildings. The paper presents LCE of twenty (20) low rise residential buildings in Indian context. LCE of the studied buildings is varying from 160 - 380 kWh/m2 year (Primary). Based on the LCE data of studied buildings, an equation is proposed to readily reckon LCE of a new building.

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.