Statistical analyses on summer energy consumption characteristics of residential buildings in some cities of China

The purposes of this paper are to analyse energy consumption characteristics and to find out influence factors of residential energy consumption in summer in typical cities of China. The investigated residences were located in seven cities of five architecture thermotechnical design zones. Questionnaire surveys revealed housing unit characteristics, household characteristics, the possession and utilization of domestic energy consuming appliances and indoor thermal environment in summer. Energy consumption analyses show that summer energy consumption amounts in different cities bear distinct regional characteristics: the household amounts of electricity use are largest in Hongkong, and the values are smaller but still at a high level in Beijing, Shanghai and Changsha, and at the smallest level in Kunming, Harbin and Urumqi, while the difference in gas use is small among these cities. Influence factor analyses show that city locations, housing unit characteristics, the utilization of space coolers and water heaters, household characteristics, and subjective evaluation of indoor thermal environment all contribute to the residential energy consumption in summer when taking all the families in the seven cities as the sample collectivity, while detail analyses for separate cities shows each city has its own characteristics. In Shanghai, the satisfaction rate of thermal environment, the possession and operation of air conditioners and housing unit characteristics greatly affect the summer energy consumption, but the electrical fan is judged as the non-influence factor, while in Urumqi, the possession and operation of electrical fans and the categories of water heaters have remarkable effect, and the influence of housing unit characteristics is also distinct, but the number of air conditioners and their usage contribute little to energy use due to the cool climate.     

Contrastive analyses on annual energy consumption characteristics and the influence mechanism between new and old residential buildings in Shanghai, China, by the statistical methods

The purposes of this research are to contrast the energy use characteristics of old residential buildings and new residential buildings in Shanghai, China, to look into influence factors of residential energy consumption, and to further analyze the reasons which result in the differences of energy consumption quantities between high-energy use family group and low-energy use family group. 1610 families in Residential District A and 819 families in Residential District B were chosen to trace their monthly energy consumption data in the whole year of 2006. Buildings in District A were all constructed in the 1980s, while those in District B were built in the 2000s. 300 families in each district were further selected from all above investigated families to do questionnaires in the year of 2007, so as to understand building characteristics, the possession and utilization of space heating and cooling appliances, and energy-saving consciousness. Annual energy consumption of the two kinds of buildings is contrasted and energy consumption quantities of spacing cooling and heating are also calculated. Influencing factors of residential energy consumption are analyzed by Quantification Theory I. Quantification Theory III is used to classify all the families into different categories based on the differences in their energy consumption amounts, and to further find out the reasons leading to the different energy consumption between different groups. Conclusions are as follows: (1) the average annual energy consumption quantity is 23.27 GJ/household for new buildings and 14.40 GJ/household for old buildings. The ratio of space heating and cooling to total annual energy consumption is just 16% and 11.6% for new buildings and old buildings respectively; (2) energy consumption and its variance lie on the integration of many factors, such as the floor area, materials of window frames, the number of family members, operation months of space heaters in winter and air conditioners in summer, and energy-saving actions; (3) all the families in the two districts can be classified into two categories: Household Region M of much energy use, and Household Region N of little energy use. Adopting the aluminum window frames, large floor areas and the large number of family members (above 4 person) are the main reasons leading to more energy use in Household Region M, while the small number of family members (1-2 persons/household) and small floor areas are the main reasons resulting in the less energy use in Household Region N; the long period of space heating, using illumination as little as possible are also the reasons causing the differences in energy consumption quantities between the two categories, but their influences on the samples clustering are smaller than the main reasons above; (4) compared with the energy consumption in some developed countries, the ratio of space heating and cooling to total residential energy use is much smaller in Shanghai. Indoor thermal environment is very poor besides that. With the growth of economy and the improvement of living standard, people will have the higher requirement for good-quality indoor thermal environment, and hence space heaters and coolers will be used much more frequently, so the residential energy consumption in China will still continuously increase rapidly, if few energy-conservation strategies are adopted; (5) considering current little prevalence of energy-saving actions with low efficiency, more effective energy-saving actions should be fully adopted in China.     

Inherent variability of heat consumption in residential buildings

The paper concerns thermal energy consumption in residential buildings. Heat consumption data of 2280 buildings are compared. Special attention is given to compare heat consumption in identical buildings. Heat consumption variability analysis enables to evaluate inherent heat consumption for space heating dissipation which exists even if design and construction requirements are met. The attempt is made to find the numeral value of heat consumption dissipation caused by design and construction allowances. The analysis of multiflat panel sister-buildings annual heat consumption reveals that minimal value of maximal and minimal heat consumption ratio in identical panel buildings reaches 1.22 (95% confidence level). Data scatter testify erratic quality of construction works, in other words, maximal and minimal heat consumption ratio trend reflects quality of construction works as a whole. On the other hand awareness of inherent unavoidable heat consumption difference in similar houses may strengthen residents’ and policy makers’ confidence in energy saving tools and enhance thermal renovation of residential buildings.     

A statistical method to investigate national energy consumption in the residential building sector of China

The purpose of this research is to found a national statistical system of energy consumption in the residential building sector of China, so as to look into the actuality of residential energy consumption, and to provide data support for building energy efficiency work in China. The frame of a national statistical system of residential energy consumption is presented in this paper, according to current status of the climate, social and historic conditions, and energy consumption characteristics in the five architecture climate divisions in China. The statistical index system of residential energy consumption is constituted which refers to housing unit characteristics, household characteristics, possession and utilization of energy consuming equipment, and residential energy consumption quantities. This index system suits for all the different utilization structures of residential energy consumption in different architecture climate divisions. On this base, a complete set of statistical reports is worked out to measure the energy consumption of cities, provinces and the country stage by stage. Finally the statistical method above is applied to measure residential energy consumption by case studies, in order to validate the feasibility of this method. The research in this paper covers the first step of the elaboration of the statistical method to investigate energy consumption in China, and more work will be done in future to further impel national statistics of residential energy consumption.     

Benchmarking Hong Kong and China energy codes for residential buildings

Mandatory energy codes to curb energy use of residential buildings have been formally launched in China for more than two decades but little has been publicized in literature. Similar codes are not available for residential buildings in Hong Kong, but most residential buildings in Hong Kong, especially public housing estates, are HK-BEAM certified to demonstrate their compliance with regulatory and basic design requirements. Given HK-BEAM is internationally recognized and there are doubts about the effectiveness of the China codes, how the energy efficiency of the HK-BEAM certified buildings compare with buildings in compliance with the China codes is of interest to most building designers and policy makers. This paper describes how the energy efficiency of a case study building in compliance with the China codes compare with the one in compliance with HK-BEAM. The energy simulation by HTB2 and BECRES reveal that the case study building in compliance with the China codes is 51.1% better in energy use. In the study, the relative impact of each compliance criterion on energy use and cooling load has been quantified by sensitivity analysis. The sensitivity values indicate that energy use is most sensitive to air-conditioning operation hours, indoor design temperature, coefficient of performance (COP) of the room air-conditioners (RAC) units, and the envelop characteristics. The results of this study indicate that a HK-BEAM certified building cannot satisfy the China codes requirements. This provides good reference to the policy makers, the building owners, and to the China and Hong Kong Governments when considering reciprocal recognition of building energy codes.     

住宅建筑能耗统计方法的研究

根据我国建筑热工气候区划下的气候、社会等条件以及供暖空调方式等特点,提出了住宅建筑能耗统计体系的框架。从住宅建筑概况、住户基本资料、能耗设备的拥有量和使用情况以及住宅能耗量等方面建立起住宅建筑能耗统计指标体系,在此基础上制定了整套报表以对市、省以及全国范围内的住宅建筑能耗情况逐层进行统计,并以湖南省某市住宅建筑能耗情况为例进行统计分析,以验证统计方法的可行性。     

Dynamic characteristics and wind-induced response of two high-rise residential buildings during typhoons

Two high-rise residential buildings in Hong Kong, among the tallest in the world, were equipped to monitor their wind-induced dynamic response. The effects of typhoon Imbudo and typhoon Dujuan on the buildings are presented in detail. Upcrossing analyses performed on the acceleration data indicate the wind-induced response of the buildings during typhoons Imbudo and Dujuan follow a Gaussian distribution. Natural frequencies of vibration in two orthogonal translational and torsional directions are estimated by empirical, numerical, and experimental techniques. A comparison between these natural frequencies reveals that experimental values are higher than empirically or numerically predicted values. This finding suggests that tall, reinforced concrete (RC) buildings in Hong Kong are stiffer than similar buildings in other countries.     

Modeling water consumption and flow rates for flushing water systems in high-rise residential buildings in Hong Kong

The probable maximum flow rates and flushing water consumption of a residential development are two crucial design factors for flushing water plants and evaluation of the risk of overloading them. Flushing water demands are transient and influenced by occupant load variations, occupant usage patterns, installed appliances and system commissioning. This study proposes mathematical expressions to determine the water consumption and flow rates for flushing water systems of residential buildings in Hong Kong. The model parameters were identified from a recent survey on the water closet (WC) usage patterns of 14 high-rise residential buildings. The occupant load factor, diurnal variation of flushing, discharge and refilling durations and volume of the WC cistern recorded from 597 households were used to determine the uncertainties of consumption and flow rates, and hence the risk of overloading a plant. Predictions were made for two typical residential buildings in Hong Kong. Good agreement between the predicted and the measured flushing water consumption was found. This model would be useful in calculating the capacity of a flushing water plant and the associated risk of overloading it.     

Statistical analysis of the Greek residential building stock

The latest developments in the field of energy supply, along with the major issue of the environment protection, set new priorities and yardsticks concerning the energy policies implemented worldwide. The development and implementation of effective energy conservation policies has been a target of the European Union ever since the days when it was still called European Economic Community. In this framework, and despite the successes already monitored, the need for further energy conservation in the building sector is a both an aim and a tool. Emphasis is being placed on the residential building stock and the improvement of its energy performance. Greece has been one of the last countries to adopt the Directive on the Energy Performance of Buildings. A thorough research regarding the nature of the Greek residential building stock helps in highlighting the problems associated with this delay, but also the perspectives for catching up with the other EU member states and achieving the aims set for the coming years. This paper aims at providing detailed information on the residential urban building stock, as determined in a field study in typical big and smaller Greek cities.     

Evaluation of the impact of internal partitions on energy conservation for residential buildings in Serbia

In Serbia, around 50% of energy is used in built environment and most of it for 6-month heating in residential buildings. Because of actual international efforts to protect environment, energy conservation in heating in residential buildings is an issue of permanent research interest. In this paper, we tried to determine how type of partitions inside a residential building influences energy consumption and demand for houses in cold climate and consequently energy conservation. For a typical house in Serbia, by using software HTB2, it was evaluated how its heating depends on six applied types of partitions. It was found that (1) the house with glass-wool partitions would have the minimum yearly heat consumption, (2) the house with masonry partitions would require heaters of minimum size, (3) the house with siporex partitions would require the lowest investment in partitions and heaters, and (4) the house with glass-wool partitions would yield the highest net savings during the life cycle of the house.     

Energy consumption and the potential of energy savings in Hellenic office buildings used as bank branches—A case study

Energy performance of non-residential buildings and in particular of office buildings used as bank branches is very limited. This paper presents new data from 39 representative bank branches and results from a more in-depth analysis of information from energy audits in 11 typical bank branches throughout Greece. The data was used to derive practical energy benchmarks and assess various energy conservation measures. Accordingly, the average annual total energy consumption is 345 kWh/m². The breakdown of the different end-uses reveals that HVAC averages 48% of the final energy consumption, lighting averages 35% and other office and electronic equipment average 17%. The most effective energy conservation measures reach annual energy savings of 56 kWh/m² by regulating the indoor set point temperature, while the use of HF electronic ballasts and CFL lamps may save about 22 kWh/m² and 29 kWh/m² with and without the use of the external marquee sign, respectively.     

基于全生命周期理论的住宅建筑能耗计算与分析

运用全生命周期理论,结合住宅建筑的自身特点,通过建立计算模型,对住宅建筑的能耗进行了计算与分析。找出了住宅建筑各能耗之间的内在关系,为建设节能型住宅提供相应的理论依据,以促进住宅建筑的可持续发展。     

Energy,economic and environmental performance of heating systems in Greek buildings

The introduction of natural gas in the Greek energy market broadened the options in the field of space heating. Residents in five major Greek cities can choose from a variety of different fuels and systems for heating their houses or working spaces; 12 more cities will be connected to the gas network within the next 5 years. Considering that space heating is the major energy consuming activity in the Greek building sector and that the environmental constrains imposed by the Kyoto protocol will be met only with difficulty, if at all, a strategy concerning the developments in space heating seems to be necessary. This however presupposes an elaborate analysis of the overall performance of the alternative systems, taking into consideration the particular conditions of the Greek energy system and the ‘established’ way of designing residential and mixed-use buildings. The present paper aims to present the empirical comparative results related to the three most popular heating systems operated in Greek multi-apartment and mixed-use buildings, which use three different fuels, respectively: a central oil-fired boiler, a unitary gas-fired boiler and unitary heat pumps.     

公共建筑能耗调查统计中几个问题的探讨

针对目前公共建筑的实际能耗调查和调查方法不规范、不统一的现状,着重探讨了能源消耗边界定义、不同类型能源折算方法、分项能耗拆分方法和归一化指标4个方面的已有研究成果和问题,并提出了改进方法。     

The impacts of climatic and economic factors on residential electricity consumption of Bangkok Metropolis

Bangkok Metropolis is the largest city of Thailand. It consumes electricity about 30% of the whole country (2006). The residential electricity consumption (REC) in Bangkok Metropolis has increased more than 240% over the past 20-year period. The growth in REC due to climatic and economic factors. This research investigated monthly data of ambient temperature, rainfall, relative humidity, and wind speed during the past 20-year period. And also investigated economic factors, e.g. number of houses, monthly income, and monthly shipment of air-conditioner over 5-year period. The residential electricity consumption of Bangkok Metropolis (RECB) model was created to analyze the impacts of each factor and to forecast the REC of Bangkok Metropolis for future use.     

夏热冬冷地区居住建筑空调方式的能耗评价

利用DeST软件模拟计算了夏热冬冷地区某一典型居住建筑的全年8760h逐时空调负荷值;考虑空调设备变工况和变负荷率情况下的二次能耗,计算了6种常见住宅空调方式的全年能耗值;利用空调能耗指标CEC,对住宅空调方式进行了能耗评价。     

Life cycle cost implications of energy efficiency measures in new residential buildings

The importance of the built environment from an environmental impact and energy use perspective is well established. High thermal efficiency of the constructed building envelope is a key strategy in the design and construction of buildings which limit use of active space conditioning systems. Australia's current housing stock is thermally poor and national energy performance standards are relatively weak when benchmarked against international best practice. A lack of data has impeded the policy debate and a significant gap in analysis remains a lack of empirical research into the life-cycle cost implications of increased building thermal efficiency, particularly for residential buildings. This paper applies an integrated thermal modeling, life cycle costing approach to an extensive sample of dominant house designs to investigate life cycle costs in a cool temperate climate, Melbourne Victoria. Empirical analysis provides new insights into lifetime costs and environmental savings for volume housing design options and identifies sensitive factors. Results suggest that the most cost-effective building design is always more energy efficient than the current energy code requirements, for the full time-horizon considered. Findings have significant policy implications, particularly in view of present debates which frequently present higher energy efficiency standards as prohibitive from a costs perspective.     

西安地区既有居住建筑节能改造初探

针对西安地区既有居住建筑能耗大的问题,本文通过论述既有居住建筑改造现状和能耗现状,并对其能耗进行分析,指出西安地区既有居住建筑节能改造的重点在于围护结构的改造和周边环境的改进。同时,提出了相关的节能改造措施,希望能为西安地区既有居住建筑节能改造提供参考。     

我国城镇住宅夏季空调能耗状况分析

根据调查和计算,利用模拟归纳法对我国城镇住宅夏季空调能耗状况进行了定量分析.结果表明,目前我国城镇住宅夏季空调的总体能耗水平较低,但增速较快,且不同气候区之间差异较大.2005年全国城镇住宅夏季空调总耗电量约为285亿kwh,平均耗电指标约为2.65 kWh/m2.我国城镇住宅空调能耗前4位的地区是:广东、浙江、江苏和湖北,它们的空调总能耗约占全国城镇住宅空调总能耗的51.8%,广东、福建、重庆、浙江、上海、湖北、江苏和广西的空调能耗指标较高,它们是我国城镇住宅空调节能的重点地区.     

南方地区居住建筑不同节能方案能耗分析

采用美国大型能耗模拟软件,对南方地区居住建筑能耗进行了分析计算,得出采取不同建筑节能技术后建筑的节能效果,对建筑节能设计具有一定的参考意义。