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.     

Energy efficiency labeling of buildings: An assessment of the Brazilian case

This paper addresses the application of Energy Efficiency Rating Technical Quality Regulations for Commercial, Service and Government Buildings - RTQ-C in order to ascertain whether the conventional construction system for buildings complies with these requirements. Additionally, it investigates the contribution of labeling to reducing electricity consumption by the building. To do so, the RTQ-C was applied to two buildings in order to calculate the efficiency levels of their envelopes and possible alterations are proposed for upgrading the envelope performance where pertinent. It is noted that conventional buildings adopting measures such as painting the walls and roof white, in addition to using smoked glass, are sufficient to bring the rating up to an A grade. As no specific concern was noted in the architectural designs for the buildings studied, making use of design strategies that minimize the use of electricity in these buildings, the findings of these case studies may well indicate that the RTQ-C has adopted technical requirements that are not particularly stringent. Consequently, it is believed that these requirements should be reviewed during a second stage, in order to make them more restrictive and attain further improvements in the constructed environment with better energy efficiency for buildings.     

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。     

Industrial electricity consumption efficiency and energy policy in Japan

This study analyzes the potential for energy savings by identifying inefficiencies in electricity use and their determinants in the Japanese industrial sector. Specifically, we used stochastic frontier analysis to estimate inefficiencies in electricity consumption based on data obtained from electric power companies. We identified significant determinants of electricity consumption efficiency and that changes in national energy policy following the Great East Japan Earthquake changed electricity consumption behavior. The contribution of this study is that its findings can be used to improve the cost-effectiveness of policies aimed at improving energy efficiency.     

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.     

Establishing target-oriented energy consumption quotas for buildings

The energy assessment of public buildings is currently emerging as an imperative of the Chinese government. However, in setting the overall control targets for entire regions, effective and specific energy consumption quotas (ECQs) for individual buildings are not specified. In this paper, in an effort to meet the energy conservation targets of the 12th Five-Year Plan, new methods for establishing target-oriented and equitable ECQs are proposed and applied in the assessment of a particular group of government office buildings in Beijing. The respective annual ECQs for electricity and gas were established for each building, and a corresponding year-end assessment was conducted. The core concept of the methods could be applied to other types of buildings and this concept could therefore provide important guidance for future policymaking.     

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。     

Towards a universal energy efficiency index for buildings

The growing worldwide demand for energy is basically satisfied through natural resources such as oil or natural gas generally acknowledged as being responsible for climate change through greenhouse gas emissions. The building sector accumulates approximately a third of the final energy consumption. Consequently, the improvement of the energy efficiency in buildings has become an essential instrument in the energy policies to ensure the energy supply in the mid to long term, and to meet the targets stated in the Kyoto Protocol. During the last decade and being sensitive to this fact, many national governments and international organizations have developed new regulations to achieve those targets. One of these regulations is the European Energy Performance of Buildings Directive but, to date this certification does not follow a standard procedure which is universally accepted.This paper aims to contribute to this standardization, proposing an energy efficiency index for buildings that relates the energy consumption within a building to reference consumption. The proposed energy index can be obtained in a simple manner by combination standard measurements of energy consumption, simulation and public databases. Furthermore, the index is upgradable whenever new data are available.     

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).     

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.     

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。