A procedure set to construct the optimal energy saving retrofit strategy for old residential buildings in China

Energy Conservation Strategy Research for Residential Building Refurbishment in Urban area of China

Investigation of VRF system cooling operation and performance in residential buildings based on large-scale dataset

Life-cycle energy of residential buildings in China

Analysis and modeling of air conditioner usage behavior in residential buildings using monitoring data during hot and humid season

Energy saving potential in the AC (air conditioning) system is the focus of the researchers all over the world. In China, the main problems in AC systems are the high consumption and low utilization of energy. Enormous energy is consumed by the air conditioning systems of residential buildings, which makes the energy conservation more important. Currently many kinds of central air-conditioning systems are being used in residential buildings, each has different energy efficiency and will lead to different total energy consumption. So the selection of AC system schemes is of great significance to energy conservation. In this paper, based on an existing building, six schemes of residential central AC systems are presented, and their primary energy ratios are calculated respectively. The results show that the primary energy ratio of water loop heat pump system is the maximum, which will be the optimal AC system scheme for the residential buildings, and that of household gas-fired air conditioning system is the minimum, the application of which will not be good to energy conservation from the view of energy utilization.

A detailed analysis of the embodied energy and carbon emissions of steel-construction residential buildings in China

The purpose of energy-saving retrofit of rural dwellings is to obtain a more comfortable indoor thermal environment with reasonable investment. The utilization rate of heating and air conditioning equipment for dwellings in poor rural areas is very low, and the buildings operate in natural ventilation mode all year round. Since the existing research on energy-saving retrofit is aimed at air-conditioned buildings, the research methods and results are not applicable to rural dwellings. This paper proposes a set of energy-saving retrofit evaluation methods suitable for natural ventilation buildings and applies it to the research on energy-saving retrofit of rural dwellings in cold climate regions of China. The specific process is as follows: First, this paper analyzed the current situation using field research and established a typical building model. Second, the DesignBuilder software was used to simulate all 725 schemes. Subsequently, the three main retrofit measures (replacing the external insulation windows, setting the external wall insulation layer and setting the roof insulation layer) were analyzed separately, and the optimal parameters of each retrofit measure were obtained. Finally, the entropy weight method was used to perform a multi-objective optimization analysis on all retrofit plans. The results show that 6+12A+6-mm insulating glass windows + 50-mm external wall insulation + 90-mm roof insulation is the optimal energy-saving reconstruction scheme. Compared with the benchmark building, the energy-saving rate of the optimal scheme is increased by 23.81%, and the annual adaptive thermal discomfort degree-hours are decreased by 13.17%.

Building lifetime and stock turnover are both key determinants in modelling building energy and carbon. However in China, aside from anecdotal claims that urban residential buildings are generally short-lived, there are no recent official statistics, and empirical data are extremely limited. We present a system dynamics model where survival analysis is used to characterise the dynamic interplay between new construction, aging, and demolition of residential buildings in urban China. The uncertainties associated with building lifetime were represented using a Weibull distribution, whose shape and scale parameters were calibrated based on official statistics on floor area up to 2006. The calibrated Weibull lifetime distribution allowed us to estimate the dynamic stock turnover of Chinese urban residential buildings for 2007 to 2017. We find that the average lifetime of urban residential buildings was around 34 years, and the overall residential stock size reached 23.7 billion m2 in 2017. The resultant age-specific sub-stocks provide a baseline for the overall stock, which—along with the calibrated Weibull lifetime distribution—can be used in further modelling and for analysis of policies to reduce the whole-life embodied and operational energy and CO2 emissions in Chinese residential buildings.

To assist in the implementation of carbon peaking and carbon neutrality in China, due to the contradiction between the increasing energy consumption of residential buildings in China and the higher energy efficiency goals, this paper illustrates that the energy consumption constitution of residential buildings in the whole life cycle and then puts forward comprehensive energy efficiency strategies. With literature and statistical data, the main part of building energy consumption lies in the materialization and use phases, which both will be continually increasing, and divided into energy utilization and waste. By inducing the energy consumption in the use phase, the energy consumption of residential buildings can be further classified into the energy consumption of indoor environments, residential behavior, and public facilities, where the internal factor of continuous increase are all elaborated. Via the analysis of energy waste causes, this paper constructs a model of energy consumption in residential buildings, reveals that the key to energy efficiency in residential buildings lies in scientific decision-making, lifestyle improvement, and appropriate energy efficiency technologies and measures adoption, and points out that promoting building energy efficiency through the whole life cycle of buildings and building activities is needed to achieve carbon compliance and carbon neutrality.

Progress in energy-efficiency standards for residential buildings in China

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.

Variable Refrigerant Flow (VRF) systems are becoming increasingly popular in commercial and residential buildings due to their flexibility and efficiency. Building design and operational parameters play an important role in the process of predicting cooling loads, and these variables contain a variety of uncertainties that must be taken into account when seeking to obtain a reliable prediction. It is common practice to oversize the Heating, Ventilation, and Air Conditioning (HVAC) system installed in a building in order to reduce uncertainties in its performance. However, oversizing is undesirable due to additional capital and operating costs, inefficient space utilization, and excessive emissions of greenhouse gases. This study provided a comprehensive literature review on previous uncertainly analysis studies from six perspectives: classification of uncertainty factors, sensitivity analysis methods, building energy model for uncertainty analysis, sampling method, the most effective parameter, and distribution of uncertainty parameters., and then developed a framework to investigate the effects of uncertainty of operational and design parameters on annual cooling load, total energy consumption, HVAC electricity use per conditioned floor area, VRF system cost, and the cooling-to-total electricity consumption ratio (R) in residential buildings equipped with VRF systems located in the Middle East (ME) region (Kuwait City, Tehran, and Istanbul). Artificial Neural Network (ANN) model was also developed to predict output parameters in residential building. Latin Hypercube Sampling (LHS) simulation was also applied to generate near-random samples of uncertainty parameter values from a multidimensional distribution. It should be mentioned that a correlation was derived in this study to predict VRF cost. The study evaluated thirteen uncertainty parameters related to building characteristics, occupants, building energy systems, VRF variables, and lighting conditions. Several methods were used to evaluate the effects of input uncertainty parameters on the output variables, namely, the Standardized Regression Coefficient (SRC), Partial Correlation Coefficient (PCC), and Spearman Rank Correlation Coefficient (SRCC) or Pearson Product-Moment Correlation Coefficient (PPMCC). The results indicated that VRF cost and HVAC electricity use per area have a greater coefficient of variation compared with other output parameters. The density distribution of output parameters indicated that uncertainty parameters had the greatest impact on output parameters in Kuwait (hyper arid climate), whereas in Istanbul (humid subtropical climate), they were the least. Among the variables examined in the Sensitivity Analysis (SA), cooling setpoint had the greatest impact on residential building energy consumption in ME climates. Finally, this paper highlights emerging trends and offers recommendations for advancing future research in the realm of building energy uncertainty analysis.

As the two largest emerging emitters with the highest growth in operational carbon emissions from residential buildings, the historical emission patterns and decarbonization efforts of China and India warrant further exploration. This study aims to be the first to present a carbon intensity model considering end-use performances, assessing the operational decarbonization progress of residential building in India and China over the past two decades using the newest decomposing structural decomposition approach. Results indicate (1) the annual operational carbon intensity increased by 1.4% and 2.5% in China and India, respectively, between 2000 and 2020. Household expenditure-related energy intensity and emission factors were crucial in decarbonizing residential buildings. (2) Building electrification played a significant role in decarbonizing space cooling (−87.7 in China and − 130.2 kg of carbon dioxide (kgCO2) per household in India) and appliances (∼ −169.7 in China and ∼ −43.4 kgCO2 per household in India). (3) China and India collectively decarbonized 1498.3 and 399.7 M-tons of CO2 in residential building operations, respectively. In terms of decarbonization intensity, India (164.8 kgCO2 per household) nearly caught up with China (182.5 kgCO2 per household) in 2020 and is expected to surpass China in the upcoming years, given the country's robust annual growth rate of 7.3%. Overall, this study provides an effective data-driven tool for investigating the building decarbonization potential in China and India, and offers valuable insights for other emerging economies seeking to decarbonize residential buildings in the forthcoming COP2811COP28 is the abbreviation of 2023 United Nations Climate Change Conference. age.

Energy conservation and sustainability have become an attractive field for research due to the growth in population and continuing search for better living standards. Heating, Ventilation, and Air Conditioning (HVAC) systems account for almost half of consumed energy in buildings and around 10 to 20% of total energy consumption in developed countries. In general, the trend of installing central HVAC systems increases in residential and commercial buildings. In this research, a study of energy consumption of HVAC systems in residential buildings has been conducted with the aim to compare those systems from an energy consumption point of view. The final goal of this research is to reduce energy requirements of residential buildings sector to save energy and reduce carbon emission. A medium size residential building in the city of Tripoli, Libya, was selected as a case study. EnergyPlus building simulation software along with OpenStudio software were used to model the house and HVAC systems. The results show that the virtual component “ideal air loads” used in EnergyPlus is very easy to use, however, its calculated energy consumption is overestimated compared to other models. Therefore, using that component can be misleading and may result in high monthly and annually energy consumption results. The results also show that in a residential building, unitary systems consume the least annual energy consumption compared to other models. It was concluded that variations in energy consumption of the considered HVAC systems decrease as the coefficient of performance (COP) increases and visa verse.

A Review on Solar Powered Air Conditioning System