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.     

Cost premium prediction of certified green buildings: A neural network approach

Built environment has a substantial impact on the economy, society, and the environment. Along with the increasing environmental consideration of the building impacts, the environmental assessment of buildings has gained substantial importance in the construction industry. In this study, an artificial neural network model is built to predict cost premium of LEED certified green buildings based on LEED categories. To verify the viability of the model, multiple regression analysis is used as a benchmarking model. After validating the prediction power of the neural network model, a global sensitivity analysis is utilized to provide a better understanding of possible relationships between input and output variables of the prediction model. Sustainable Sites and Energy & Atmosphere LEED categories were found to have the highest sensitivity in cost premium prediction. In this study, our goal was to reveal the significant relationships between LEED categories and the cost premium, and offer a decision model that can guide owners to estimate cost premiums based on sought LEED credits.     

Die wachsende Bandbreite der Gebäudetypen für LEED‐Zertifizierungen

Im Bereich der Nachhaltigkeitszertifizierungen von Gebäuden ist das vom USGBC (US Green Building Council) entwickelte LEED (Leadership in Energy and Environmental Design) in Europa und Deutschland ein fester Begriff [1]. Während inzwischen das System LEED‐NC, also für Neubauten und Generalsanierungen, sehr bekannt ist und am häufigsten angewandt wird, sind neun weitere LEED‐Zertifizierungssysteme entweder auf dem Markt oder in Entwicklung. Diese ermöglichen es u. a. auch, bestehende Gebäude zu zertifizieren und auf die Anforderungen spezieller Gebäudenutzungen, wie Krankenhaus, Schule oder Einzelhandel, einzugehen. The expanding variety of building types for LEED certification is continuously. In Europe and Germany, LEED (Leadership in Energy and Environmental Design), developed by the USGBC (US Green Building Council), plays a major role in Green Building certifications [1]. Although the system LEED‐NC for new construction and major renovations is commonly known and mostly used, 9 additional LEED certification systems are either available or currently in development. Besides others, those systems allow the certification of existing buildings and account for buildings with specific requirements, such as hospitals, schools or retail.     

上海地区绿色建筑LEED认证的现状与思考

介绍“能源及环境设计先锋奖（LEED）”认证的国际化情况及在上海地区认证的获奖级别、项目类型、业主类别、设计与咨询机构。在对现状进行梳理并与绿标认证建筑进行对比后认为,今后应引导更多的建筑向绿色转移。     

Energy modeling of two office buildings with data center for green building design

Energy simulation models are developed with EnergyPlus for two office buildings in a R&D center in Shanghai, China to evaluate the energy cost savings of green building design options compared with the baseline building. As a R&D center of an international IT corporation, there are data centers in the two buildings, which make them different from typical office buildings. The data centers house high energy consuming IT equipments and need 24 h air-conditioning every day all year round. In order to achieve energy cost savings, multiple energy efficiency strategies are employed for design proposed building, encompassing high performance building envelope, lighting system, and HVAC system. Through energy modeling, the design proposed options are compared to an ASHRAE 90.1-2004 compliant budget model to highlight energy cost savings versus “standard practice” and show the potential LEED™ Credit EA1—Optimize Energy Performance. Meanwhile, they are also compared to China Code model to figure out the energy cost savings versus the most popular practice conforming to China Public Building Energy Saving Design Standard. The whole building energy simulation results show that the yearly energy cost saving of the proposed design will be approximately 27% from China Code building and 21% from ASHRAE budget building, which can achieve 4 points for LEED credit due to energy performance optimization.     

新建项目LEED认证节能设计

LEED(Leadership in Energy and Environmental Design)作为评价绿色建筑的工具,其宗旨是在设计中有效地减少环境和住户的负面影响,规范一个完整、准确的绿色建筑概念,防止建筑的滥绿色化.LEED由美国绿色建筑协会建立并于2003年开始推行,在美国部分州和一些国家已被列为法定强制标准,而且现中国已有多个项目进行了LEED认证.通过案例分析了LEED认证项目的节能应用和设计方法,阐述了其在设计时的主要内容.     

Estimation models for heating energy and electricity costs

Heating energy and electricity represent a significant proportion of the overall financial expenditures over the life cycle of buildings and play a decisive role in the assessment of ecological quality. To ensure ecological and economical sustainability, the planning and construction of energy efficient buildings have become increasingly important. The present study introduces statistical models for the estimation of energy costs during the planning process as well as for the purpose of monitoring and controlling costs during operation including a wide range of facility types. Based on a data sample of 206 occupied facilities located in Germany, regression models are presented in detail including significant predictor variables. The provision of correctly specified models as well as a consistent and unbiased estimation beyond the employed data is verified by validation tests. The practical significance of the determined variables is presented by the calculation of various scenarios. The best estimation accuracy is indicated for regression models with transformed response and predictor variables achieving mean absolute percentage errors of 20.5% (heating energy) and 20.7% (electricity), respectively. An extension of the data sample, a consideration of further facility types, and an implementation of additional statistical methods may be considered by future approaches to improve the estimation accuracy.     

Do LEED-certified buildings save energy? Yes, but…

We conducted a re-analysis of data supplied by the New Buildings Institute and the US Green Buildings Council on measured energy use data from 100 LEED-certified commercial and institutional buildings. These data were compared to the energy use of the general US commercial building stock. We also examined energy use by LEED certification level, and by energy-related credits achieved in the certification process. On average, LEED buildings used 18-39% less energy per floor area than their conventional counterparts. However, 28-35% of LEED buildings used more energy than their conventional counterparts. Further, the measured energy performance of LEED buildings had little correlation with certification level of the building, or the number of energy credits achieved by the building at design time. Therefore, at a societal level, green buildings can contribute substantial energy savings, but further work needs to be done to define green building rating schemes to ensure more consistent success at the individual building level. Note, these findings should be considered as preliminary, and the analyses should be repeated when longer data histories from a larger sample of green buildings are available.     

Benchmarking energy use assessment of HK-BEAM,BREEAM and LEED

The Hong Kong Building Environmental Assessment Method (HK-BEAM), Building Research Establishment Environmental Assessment Method (BREEAM) and LEED were formally launched in the 1990's. How well the certified and rated buildings compare with each other of an interest to building designers and policy makers. This paper describes how the baseline buildings, performance criteria and the credit scales of the three schemes compare with each other. By statistical analysis of the energy assessment results of 60 HK-BEAM certified buildings and the available data for BREEAM and LEED, it seeks to ascertained of buildings scoring excellent energy performance under different schemes belong to the top 5% in the market. Through this exercise, a systematic approach to benchmark the energy assessments across schemes has been established. With people nowadays paying greater attention to the environmental issues and the rapid development of the environmental schemes in various parts of the world, this study forms a good basis for future benchmarking of energy assessment schemes across nations.     

BIM和可持续性一体化课程

绿色建筑和可持续性施工一直以来都被列入本科和研究生阶段的施工管理项目课程中。在这类课程中,能源与环境设计认证(LEED)绿色建筑评级系统是一项重要课题。大学中现有的LEED教学一般都仅限于教科书和参考书中的基础理论。由于缺乏实践经验,学生们通常都难以理解LEED系统的基本原理,因此也不能理解LEED项目是如何在工程领域中实现的。本文将探讨林克尔(Rinker)建筑学院通过整合BIM,研究实验出一种能够促进可持续性的创新教学方法。BIM-for-LEED教学模式以佛罗里达大学校园中已通过LEED认证的建筑为例,利用先进的BIM制作和分析工具来表达成功获得LEED认证的关键设计因素。这个教学重点强调了满足LEED认证所需的设计要素,以及满足这些要素所需的BIM解决方案中的功能性。教学中所设置的课程和实验,都是为了进一步扩展学生在计算机辅助的可持续性设计方面的知识,更重要的是,亲自参与建模实验可以了解满足LEED认证的设计流程的最基本元素。在学期结束时,学生们不仅对可持续性和LEED评级系统有了更深入的理解,同时还掌握了关于LEED认证建筑建模的扎实技能。利用校园中LEED项目的优势在于学生们可以随时看到这些建筑,并分辨出其设计和实际建成建筑之间的区别,从而丰富了他们对从设计阶段到施工阶段,乃至建筑运营和维护阶段的可持续性设计和LEED的理解。     

Grün ist nicht gleich Grün – Einblicke in das LEED‐Zertifizierungssystem

LEED – The Green Building Rating System. Buildings in the USA are commonly not perceived as energy efficient and sustainable. Considering this, it comes as a surprise that the LEED (Leadership in Energy & Environmental Design) certification system is leading the process to certify “Green Buildings” despite the broad range of certification systems in countries such as BREEAM in England, CASBEE in Japan, HQE in France, Green Star in Australia, and most recently DGNB in Germany. International companies are pursuing the LEED certification due to its worldwide applicability – over 20,000 buildings in 76 countries are currently registered.     

Energy use in Minnesota State-owned facilities

This paper describes and analyzes the contents of a large data base containing information on monthly energy use at state-owned facilities in Minnesota. The data base, managed by the State Department of Administration, includes information on 42 community colleges, state universities, hospitals, prisons, and the St. Paul Capitol Complex. The data span a seven year period (1972 – 1978) and include about 3,500 observations.Several data base management issues are discussed. These include errors and their correction, development of simple and consistent definitions for key terms, and collection of information on key determinants of energy use at these facilities.Total annual energy use at these 42 institutions averaged 245 kBtu/ft² (2.78 GJ/m²) for 1978. Fossil fuels accounted for 56% of this total; electricity accounted for the remainder. Energy use at the Capitol Complex, hospitals and prisons was higher than average.Regression equations were developed to predict monthly heating fuel use and total energy use. These equations show that more than 60% of the variation in energy use per unit floorspace can be explained by a few variables: heating degree days; electricity and fossil fuel prices; number of buildings; number of boilers; facility age; and whether or not the facility is all electric.     

Climate co-benefits of green building standards: water,waste and transportation

This paper quantifies the greenhouse gas (GHG) emissions co-benefits associated with water, waste and transportation usage in certified green commercial office buildings in California. The study compares the measured values of water, waste and transportation usage self-reported by office buildings certified under the Leadership in Energy and Environmental Design rating system for Existing Building Operations and Maintenance (LEED EBOM) to baseline values of conventional California office buildings. The green buildings in the LEED EBOM dataset produced 50% less GHGs due to water consumption than baseline buildings, 48% less due to solid waste management, and 5% less due to transportation. If applied to the entire California office building stock, performance typical of the certified green buildings would save 730,038?MgCO₂e/yr (metric tonnes) from transportation, 87,601?MgCO₂e/yr from water, and 45,280?MgCO₂e/yr from waste, for a total potential savings of about 862,920?MgCO₂e/yr relative to conventional construction. In addition, buildings earning additional credits for specified performance thresholds for water and waste in the LEED EBOM code attained performance levels even higher than required by the code provisions, suggesting that such code provisions in other contexts may help incentivize larger GHG emissions reductions than anticipated. Specific recommendations are made for building standards and certification schemes.     

Do LEED-certified buildings save energy? Not really…

Newsham et al. have recently published a re-analysis of energy-consumption data for LEED-certified commercial buildings supplied by the New Buildings Institute (NBI) and US Green Building Council. They find that, on average, LEED buildings use 18-39% less energy per floor area than their conventional counterparts, consistent with and adding clarity to conclusions originally reached by NBI. These conclusions, however, hang on a particular definition of the mean energy intensity of a collection of buildings that is not related to the total energy used by those buildings. Furthermore, site energy considered by Newsham et al. and NBI, unlike source energy used for the EPA's building Energy Star rating, does not account for the energy consumed off-site in generating and delivering electric energy to the building, whose inclusion is crucial for understanding greenhouse gas emission associated with building operation. Here I demonstrate that both the site energy and source energy used by the set of 35 LEED office buildings and Newsham et al.’s matching CBECS office buildings are statistically equivalent. Hence Newsham et al. offer no evidence that LEED-certification has collectively lowered either site or source energy for office buildings.     

建筑遮阳在北京建筑工程中应用建议

我国已发布的《公共建筑节能设计标准》（GB50189—2005）和《严寒和寒冷地区居住建筑节能设计标准》（JGJ26—2010）中,已对严寒和寒冷地区的公共建筑和居住建筑均规定了应对透光围护结构设置遮阳设施的要求。对于在北京地区采用遮阳设施的方式和遮阳装置的类型,根据北京地区气候特点进行了分析比较,提出了适用于北京地区居住建筑和公共建筑透光围护结构的遮阳装置类型。     

节能服务公司(EMC)与用能方的契约关系研究——一个关系契约的视角

合同能源管理是一种基于诚信和契约的商业运作模式。从关系契约的角度研究其实施的两大中心主体——节能服务公司与用能方之间的契约关系,分析了双方契约关系的特殊性。借鉴有关前人的研究成果,提出了治理这一契约关系的两种治理模式——双边治理与统一治理,以促进双方的真诚合作。     

与产业和设施管理部协作教授建筑信息模型

2011年夏天,科罗拉多州立大学（CSU）与产业和设施管理部合作,试开了一门使用BIM的实验课程。在此项课程中,学生们将校园建筑建模,并用模型来探索和推动在现有的建筑和正在施行的管理项目中应用BIM的机会。在此过程中应用的软件包括草图大师（Sketch-Up）、Revit,Vico Office（某施工管理综合软件,包括量算预算施工进度及控制）和Navisworks。业内专业人士作为客座讲师来教授各种软件。通过在软件平台上的协作和练习,从而让学生体验综合的软件学习环境。学习过程中学生们先对一个校园建筑进行建模,然后根据所需功能（如进度、预算,运行等）使用不同的软件工具继续对模型在不同的软件之间进行导入,导出、重建和管理。本文讨论了此试点课程,展示了学生的作品和他们的反馈。调查结果从施工管理学生的收获出发,用于评估课程成效和价值,记录经验教训,从而加强校园管理。     

Thermal comfort and workplace occupant satisfaction—Results of field studies in German low energy office buildings

The issues of comfort and workspace quality in buildings have gained much importance with the European “Energy Performance of Buildings Directive” of 2001. New energy efficient building concepts and technologies require a revision of comfort standards, which were developed for air-conditioned buildings only. Particularly, the question of recommendable upper indoor temperature limits needs further investigation. In addition, a broader approach to occupant satisfaction in buildings is necessary with respect to overall building performance.     

Die Novelle der Energieeinsparverordnung EnEV 2007 – Chancen für die bessere Bewertung von Nichtwohngebäuden und Einführung von Energieausweisen

Amendment of the German Building Energy Conservation Ordinance (Energieeinsparverordnung – EnEV 2007) Opportunities for better assessment of non‐domestic buildings and introduction of Energy Passports. EU member states were required to implement the Energy Performance of Buildings Directive (2002/91/EC) in their respective national law by January 2006 [1]. In this context the German Government proposed comprehensive amendments of the existing energy saving legislation (‘Energieeinspargesetz’ or Energy Conservation Law, ‘Energieeinsparverordnung’ or Building Energy Conservation Ordinance). This article describes the current status of the considerations, in particular with regard to technical assessment options for non‐domestic buildings. The second amendment to the German Energy Conservation Law [7] came into force on 8 September 2005. The draft amendment of the Building Energy Conservation Ordinance (EnEV 2007) was presented by the German Government on 16 November 2006 [2]. However, due to the time required for consideration by the Federal Cabinet and the upper house of the German parliament it is not expected to come into force before mid 2007. This article provides an overview of the proposed new requirements for energy saving in buildings.     

Informing LEED's next generation with The Natural Step

Building assessment systems, such as the US Green Building Council's Leadership in Energy and Environmental Design (LEED) suite of standards, have been helpful in the initiation of a movement that is addressing the environmental impact of buildings. The approach utilized in these standards is in need of updating in order to address a number of potentially serious shortcomings. Among these are the lack of a quantifiable relationship between 'points' and environmental impacts, a 'one-size-fits-all' design for assessment, and an absence of consistent science underpinning LEED points. To address the last of these shortcomings, the potential use of The Natural Step (TNS) could form the foundation for the next generation of building assessment tools, sometimes referred to as LEED Version 3. LEED is used as an example of the potential application of TNS to remedy some of the major shortcomings of building assessment systems. The same approach would apply to voluntary, market-based building assessment systems used in other countries, e.g. the Building Research Establishment Environmental Assessment Method (BREEAM), the Comprehensive Assessment System for Building Environmental Efficiency (CASBEE), and Green Star, to name but a few.