Characteristics of electricity consumption in commercial buildings

Average annual electricity use per gross floor area is 236kWh/m²yr for offices and 366kWh/m²yr for hotels. HVAC and lighting account for 70-80% of total energy in fully air-conditioned commercial buildings in Hong Kong and should be a priority for energy management programmes.     

Basic actions to improve energy efficiency in commercial buildings in operation

Numerous studies have focused on improving energy efficiency in commercial buildings. Engineers and researchers have developed complex methods to improve energy efficiency, but buildings are often managed by non-specialised technicians who need understandable and cost-effective actions to implement in their buildings. This paper presents basic actions on which to base improvements in energy efficiency in commercial buildings in operation. Furthermore, obtained results and details of the implementation of these techniques in various buildings in the Universitat Politècnica de València are presented.     

Opaque envelope parameters versus energy consumption in commercial buildings in Brazil

This article presents an analysis of the energy performance of commercial buildings as a function of the influence of the overall heat transfer coefficient of the external walls and roof. Cases with different internal load densities, exterior absorptance, patterns of use, window-to-wall ratios and other parameters were simulated to analyse their influence on the annual energy consumption. The analysis was carried out through computer simulation using the EnergyPlus program and weather files for Florianopolis, Curitiba and Sao Luis. Two building typologies were adopted: a five-storey office building and a one-storey commercial store. These results show that the limits adopted by ASHRAE Standard 90.1 can be exceeded, depending on the case and climate analysed, as using high values of overall heat transfer coefficient in the walls can help to dissipate the internal heat gain to the exterior, minimizing the air conditioning energy consumption.     

福建省建筑节能工作初步探讨

本文就福建省近两年来在建筑节能推行过程中遇到的各种问题进行探讨,提出设计人员在设计过程中应把握的主要原则,以及现阶段节能工作存在主要问题。本文着重根据福建省地域特点,针对设计、管理过程中经常遇到的难点、疑点进行一些系统的研究和分析并提出了技术措施。     

A study of energy efficiency of private office buildings in Hong Kong

A benchmark study of the energy efficiency of private office buildings in Hong Kong was conducted in 2002 because energy efficiency was declining. In the study, private office buildings were divided into five user groups. For each group, a multiple regression model was developed to find the relationship between Energy Use Intensities (EUIs) and other factors, such as operating hours, for normalization and benchmarking purposes. In this paper we make use of the regression results to study the energy efficiency of private office buildings by different grades. In Hong Kong, office buildings are divided into three grades (A, B, and C) based on the quality of the facility, which is reflected in rental values; a Grade A office building denotes expensive luxury. We found that the EUI of Grade A office buildings is the highest, consuming over 50% of the total energy used in office buildings. Recently, the annual EUI of office buildings has improved even though Grade A floor space is increasing. This may be due to the promotion of the energy efficiency program launched in the last decade.     

A survey of building envelope designs for commercial buildings in Hong Kong

Nearly 1 million m² of gross floor area is represented by the survey which identified four different building envelope designs. To enable judgements to be made on construction cost and time, a comparative study was carried out based on a 40-storey generic office building.     

Modelling electricity consumption in office buildings: An agent based approach

In this paper, we develop an agent-based model which integrates four important elements, i.e. organisational energy management policies/regulations, energy management technologies, electric appliances and equipment, and human behaviour, to simulate the electricity consumption in office buildings. Based on a case study, we use this model to test the effectiveness of different electricity management strategies, and solve practical office electricity consumption problems. This paper theoretically contributes to an integration of the four elements involved in the complex organisational issue of office electricity consumption, and practically contributes to an application of an agent-based approach for office building electricity consumption study.     

Explaining the adoption of energy-efficient technologies in U.S. commercial buildings

This paper investigates factors explaining the adoption of energy-efficient heating, cooling, window, and lighting technologies in U.S. commercial buildings. It presents multinomial logit models of technology adoption using the 2003 Commercial Buildings Energy Consumption Survey microdata set, examining, first, fundamental building components, and, second, energy-efficient adaptations. Key findings are that the choice of fundamental building components is strongly influenced by locational factors, the activities that are expected to take place in the building, and building-specific characteristics. Lighting technologies are an exception, and are poorly explained by these factors. By contrast, energy-efficient heating, cooling, window, lighting, and control adaptations appear to share common drivers, and are more likely to be adopted in newer, larger, more energy-intensive, owner-occupied buildings. These are the buildings that can best afford the up-front costs of innovation, which is often a design-intensive process. Absent policy interventions, the energy-efficient adaptations are unlikely to diffuse rapidly to the rest of the commercial building stock.     

Principal component analysis of electricity use in office buildings

Principal component analysis was conducted on five major climatic variables—dry-bulb temperature, wet-bulb temperature, global solar radiation, clearness index and wind speed. Twenty-eight year (1996–2000) long-term measured weather data were considered. A two-component solution was obtained, which could explain 80% of the variance in the original weather data. Monthly electricity consumption data recorded during a 5-year period (1979–2006) were gathered from 20 fully air-conditioned office buildings with centralised HVAC systems in subtropical Hong Kong. Electricity use per unit gross floor area ranged from 163 to 389 kWh/m². These consumption data were correlated with the corresponding principal components using linear multiple regression techniques. The coefficient of determination (R²) varied from 0.76 to 0.95 indicating reasonably strong correlation. It was found that the regression models developed could give a reasonably good indication (mostly within 3%) of the annual electricity use, but the monthly estimates might differ from the actual consumption by up to 9%. Attempt was also made to develop a general regression model for the 20 buildings, which had an R² of 0.84 with a maximum mean-biased error of 18.6% and a maximum root-mean-square error of 21.4%.     

上海公共建筑能耗现状及节能潜力分析

根据上海地区办公楼、商办楼、宾馆和商厦能耗调研的数据，对上海公共建筑空调能耗的现状作了评价。认为上海建筑用能水平较低，用能不尽合理，提出用系统能量效率比用单位面积平均一次能耗量作为建筑节能的评价指标更为合理。     

提高体育建筑的生态效率初探

通过对体育建筑生态效率的研究，结合体育建筑的特点，提出了提高体育建筑生态效率的设计策略和具体措施，以达到体育建筑的可持续发展。     

浅论建筑节能

主要阐述了我国目前建筑节能的情况,并指出近期的工作目标,提出了建筑节能的有效技术措施,从而在保证和提高建筑舒适性的前提下,不断提高能源利用效率。     

Towards a multi-objective optimization approach for improving energy efficiency in buildings

The energy sector worldwide faces evidently significant challenges that everyday become even more acute. Innovative technologies and energy efficiency measures are nowadays well known and widely spread, and the main issue is to identify those that will be proven to be the more effective and reliable in the long term. With such a variety of proposed measures, the decision maker has to compensate environmental, energy, financial and social factors in order to reach the best possible solution that will ensure the maximization of the energy efficiency of a building satisfying at the same time the building's final user/occupant/owner needs. This paper investigates the feasibility of the application of multi-objective optimization techniques to the problem of the improvement of the energy efficiency in buildings, so that the maximum possible number of alternative solutions and energy efficiency measures may be considered. It further shows that no optimal solution exists for this problem due to the competitiveness of the involved decision criteria. A simple example is used to identify the potential strengths and weaknesses of the proposed approach, and highlight potential problems that may arise.     

A method for heating consumption assessment in existing buildings: A field survey concerning 120 Italian schools

A field survey was carried out in order to collect, elaborate and analyse data concerning the actual energy consumption for space heating of a sample of about 140 buildings (120 high schools) in the Province of Torino (Italy).     

北京市《公共建筑节能评审标准》简介

北京市大型公共建筑单位建筑面积的全年耗电量高达100~350 kWh/(m2·a),是普通居民住宅的10~15倍,节能潜力达到30%~50%。不节能的原因之一是设计方案本身存在问题,强制性的节能设计标准没有得到执行。解决的途径是通过大型公共建筑的节能评审标准对设计方案进行节能审查和评估。所介绍的节能评审标准是对大型公共建筑能源需求、转换和消耗过程中建筑本身、能源转换和设备系统、可再生能源三个环节的多项指标给出定量的详细模拟计算结果,从而对设计方案的节能性给出全面评价,作为政府审批固定资产投资项目、鼓励和奖励节能设计的依据。     

Using intelligent clustering techniques to classify the energy performance of school buildings

The present paper deals with the energy performance, energy classification and rating and the global environmental quality of school buildings. A new energy classification technique based on intelligent clustering methodologies is proposed. Energy rating of school buildings provides specific information on their energy consumption and efficiency relative to the other buildings of similar nature and permits a better planning of interventions to improve its energy performance. The overall work reported in the present paper, is carried out in three phases. During the first phase energy consumption data have been collected through energy surveys performed in 320 schools in Greece. In the second phase an innovative energy rating scheme based on fuzzy clustering techniques has been developed, while in the third phase, 10 schools have been selected and detailed measurements of their energy efficiency and performance as well as of the global environmental quality have been performed using a specific experimental protocol. The proposed energy rating method has been applied while the main environmental and energy problems have been identified. The potential for energy and environmental improvements has been assessed.     

基于节能评估的商住楼建筑能耗分析

民用建筑节能评估工作利国利民,从社会效益看,控制了项目总能耗;从建设单位看,控制了整体造价;从消费者看,宜居程度得到了保障。从温州生态园某商住楼项目实际情况出发,结合项目特点和当下主流建筑技术手段、科学分析手段,实践低碳城市建设,供业内同行参考。     

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.     

Occupants have little influence on the overall energy consumption in district heated apartment buildings

The purpose of this research is twofold: first, to evaluate how occupant behavior in a neutral environment influences the overall greenhouse gas emissions and energy consumption of multi-family apartment buildings, and second: to establish which activities associated with housing companies produce the most greenhouse gas emissions. The research comprised of a multiple cases of housing companies dating from the late 1960s and located in the Finnish capital Helsinki. The studied housing companies represent the least energy efficient third of the Finnish residential building stock, approaching obligatory large scale refurbishments. The analysis is conducted in two phases with a so called hybrid life-cycle assessment (LCA) technique. Using the technique, both economic and metric consumption data are analyzed to estimate the greenhouse gas emissions generated by activities associated with housing. In line with previous research, the study identifies heating energy as the single most significant contributor to greenhouse gas emissions. The results also show that the carbon load associated with housing activities makes up one third of an individual resident's overall carbon footprint. Contrary to often stated belief, the study indicates that occupant behavior has only limited effect on the energy consumption and, consequently, carbon emissions derived from housing, particularly when multi-family housing connected to district heating is concerned. However, apartment size seems to have a two-way impact, the smallest and the largest being the least energy efficient.     

Optimization of the management of building stocks: An example of the application of managing heating systems in university buildings in Spain

The article presents the implementation of management measures that have reduced the gas consumption for space heating of a university building in Spain by 40%. The measures affect the use of the building, e.g., the use of its spaces, and the scheduling of its occupancy. They also affect the management of the heating system: a protocol for turning the system on and shutting it off has been developed.The work is part of a framework for action by the Technical University of Catalonia covering more areas and for a longer period of time, in which policies have been designed for managing buildings and a number of studies have been developed on the energy consumption of the university's buildings. The article highlights the work methodology proposed to achieve the energy savings calculated theoretically in a previous study. The implementation of these measures in the case, from November 2006 until May 2007, has reduced consumption from 113.2 kWh/m² to 68.7 kWh/m² a year; thus, the hypothesis has been validated. In addition, it was possible to examine methodological details more closely. Finally, the relationship between the people involved in the process (the building owners, managers and energy users) is a determining factor.