Development of a methodology for selecting office building upgrading solutions based on a test survey in European buildings

The potential for using the TOBUS methodology to select office building upgrading solutions have been investigated during field tests in 15 European office buildings in 5 European countries. The 15 office buildings represent a variety of building traditions, architectural designs, construction periods and energy and indoor performance. The buildings were audited following the TOBUS methodology developed within the project. The results of the test surveys were primarily used to improve the TOBUS methodology and secondly to suggest general upgrading solutions and energy retrofit measures for the surveyed buildings. This paper describes the development of the TOBUS methodology based on the 15 test surveys.     

建筑运行能耗监测与节能诊断系统的开发

国家机关办公建筑和大型公共建筑的高耗能问题日益突出,该类建筑的节能改革正成为当前建筑节能工作的重点,因此做好此类建筑运行能耗尤其是暖通空调设备运行能耗的监测与节能诊断分析对实现"十一五"节能目标有重要意义.本文设计开发了建筑运行能耗监测与节能诊断系统硬件子系统,该系统不仅能监测耗能量,还能监测用能品质.主要研究内容包括以MS SQL Server 2000作为平台设计了能耗监测与数据信息数据库系统,开发了建筑运行能耗监测数据采集服务器程序与客户端查询分析程序,建筑用户凭密码可在网上查询最新的监测数据并得到分析报告,从而帮助建筑用户实现能源系统由粗放型管理转变为精细型、科学化管理.在此系统基础上,通过工程案例分析,发现空调系统中存在严重的"大流量、小温差"现象和电力系统中存在"三相不平衡"能源浪费问题.     

Assessment of energy and natural resources conservation in office buildings using TOBUS

The potential for optimum energy use and conservation of natural resources in representative southern and northern European office buildings is evaluated using the new European TOBUS methodology and software for office building refurbishment. Various scenarios are being accessed for energy and water conservation in office buildings. The proposed retrofit actions focus in the areas of space heating and cooling, artificial and natural lighting, service hot water, office equipment, elevators and sanitary water. The resulting conservation and related costs are taken into account in order to help the auditor classify the retrofit actions for an audited building. The TOBUS methodology and tools have been implemented to study four Hellenic office buildings and two from Denmark in order to demonstrate the applicability of the overall approach. Energy conservation in Hellenic and Danish buildings range for space heating from 5 to 71 and 0.5 to 6%, for space cooling from 1 to 38 and 4 to 20%, for artificial lighting from 40 to 53 and 26 to 62%, for office equipment from 13 to 62 and 13 to 87% and for elevators at 35 and 23%, respectively. Sanitary water conservation can reach 74% in all audited buildings.     

A case study for the evaluation of realistic energy retrofit strategies for public office buildings in the Southern Hemisphere

The building sector offers significant opportunities for reducing the energy consumption with considerable economic, environmental and health benefits. Governments can lead the way by retrofitting existing public buildings to reinforce their commitment to improve energy efficiency. Similar design standards, end-uses and operational profiles are usually established for public buildings based on the services they offer. Retrofitting a public building can therefore serve as an ideal test-bed for energy efficiency measures for other buildings within a particular service category. This study first analysed the current electricity consumption of a public office building in Mauritius, located in the Southern Hemisphere. A complete model of the building was created, validated and then simulated to investigate the impact of realistic retrofit strategies on the electricity consumption. Results showed that lighting retrofit achieved the most significant reduction while measures that improved the thermal envelope of the building resulted in smaller energy savings. The possibility of exploiting solar energy was explored by simulating a 70 kW_p photovoltaic system installed on the roof. An equivalent of 8.5% of the annual electricity consumption of the building could thus be generated. A financial analysis is also presented for all retrofit scenarios in terms of annual return and payback period.     

某公共建筑中央空调系统节能改造诊断技术研究

建筑物节能改造诊断技术研究是了解、分析建筑产生能耗的有效方法。本文对某办公楼中央空调系统进行现场调查与能耗分析,通过变频节能技术自动控制中央新风空调系统和供暖系统,达到节能和经济的目的。     

Building typologies as a tool for assessing the energy performance of residential buildings - A case study for the Hellenic building stock

Successful strategies towards minimizing the energy consumption and greenhouse gas emissions attributed to the building sector require knowledge on the energy-related characteristics of the existing building stock. Despite the numerous studies on energy conservation applications in buildings, current knowledge on the energy-related characteristics of the building stock still remains limited. Building typologies can be a useful instrument to facilitate the energy performance assessment of a building stock. This work is based on a harmonised structure for European building typologies (TABULA) developed for residential buildings, but the methodology may be extended to the tertiary sector as well. National typologies are sets of model buildings with characteristic energy-related properties representative of a country's building stock. The model buildings are used as a showcase for demonstrating the energy performance and the potential energy savings from typical and advanced energy conservation measures (ECMs) on the thermal envelope and the heat supply system. The proposed Hellenic residential building typology is presented for the first time along with an assessment of various ECMs that are used for an estimate of the energy performance of building stock in Greece in an effort to meet the 9% indicative national energy savings target by 2016.     

Robustness of a methodology for estimating hourly energy consumption of buildings using monthly utility bills

The evaluation of building energy consumption under typical meteorological conditions requires building energy profiles on an hourly basis. Computer simulations can be used to obtain this information, but generating simulations requires a significant amount of experience, time, and effort to enter detailed building parameters. This paper considers a simple methodology for using existing EnergyPlus benchmark building energy profiles to estimate the energy profiles of buildings with similar characteristics to a given benchmark model. The method utilizes the building monthly energy bills to scale a given benchmark building energy profile to approximate the real building energy profile. In particular, this study examines the robustness of the methodology considered with respect to the parameter discrepancies between a given building and the corresponding EnergyPlus benchmark model used to estimate its profile. Test buildings are defined by perturbing several combinations of the parameters defined in the benchmark building model. The test buildings examined are similar to the EnergyPlus, medium sized office, benchmark building in Baltimore, MD, and a total of 72 distinct test building configurations are examined. The analysis reveals that the methodology can significantly reduce the errors introduced by discrepancies from the EnergyPlus benchmark model.     

Opportunities for reversible chillers in office buildings in Europe

Europe with more than 600 millions of square meters of air-conditioned office buildings offers an opportunity to save energy and reduce CO₂ emissions by reconverting chillers into reversible heat pumps in office buildings. One of the questions asked in the framework of the IEA ECBCS Annex 48 is how to assess the energy saving potential and how to identify the most interesting building cases. The methodology proposed here is based on the simulation of office buildings representative of the building stock. The energy consumption has been simulated for different office building types in five European climatic zones on the one hand with boilers for heating and chillers for cooling, and on the other hand with reversible chillers plus back-up boilers. The results of the simulations in terms of energy consumption allow us to assess the primary energy savings and CO₂ emission reduction in Europe by reconverting chillers into reversible heat pumps. The results show that the potential of annual primary energy savings and annual CO₂ emission reduction are about 8 TWh_PE and 3 millions of tons of CO₂ in Europe-15. Even if the temperature level in terminal units can be solved using the cooling coil instead of the heating coil, a back up boiler turns generally out to be required for the coldest days in the year or when simultaneous heating and cooling demands occur.     

大型公共建筑运行能耗数据库管理系统初步开发及应用

能耗测试是既有建筑节能改造过程的必要途径,为了对测试数据进行科学有效地管理,作者初步开发了大型公共建筑运行能耗数据库管理系统,并将其应用于若干实际建筑中。本文介绍了该数据库管理系统开发过程,并对其应用结果进行了分析,说明该系统切实可行并发现在建筑耗能系统中存在若干运行问题。     

TOBUS — a European diagnosis and decision-making tool for office building upgrading

The TOBUS (a decision-making tool for selecting office building upgrading solutions) methodology and software have been developed as a result of a 2-year European research project, involving eight European institutions, in the frame of the JOULE III programme of the European Commission (EC), Directorate General XII. A structured diagnosis scheme enables architects and engineers to simultaneously handle the entire complex process of office building refurbishment or retrofit with respect to deterioration, functional obsolescence of building services, energy consumption and indoor environmental quality. The software tool can then be used to define the most appropriate and cost-effective actions, to elaborate consistent refurbishment scenarios and calculate a reasonable investment budget in the early stages of a refurbishment project. This paper provides an overview of the work performed in TOBUS and an overview of the methodology and final deliverables of the project.     

An investigation of design parameters that affect commercial high-rise office building energy consumption and demand

There are many factors that drive the energy consumption and demand in high-rise commercial office buildings. Understanding the effects of individual building parameters and two-factor interactions can be very useful for directing building audits and developing energy simulation models. A fractional factorial analysis was conducted to evaluate a large number of building parameters in an effort to quantify their effect on building energy consumption and demand. The analysis utilized building data collected from 22 building audits of high-rise commercial office buildings located in the downtown Chicago Loop area. Simulation results for three of the buildings show the effects of each factor and two-factor interactions on energy consumption and demand over a set of climate zones. The factors of primary importance include lighting and equipment power density, chiller efficiency, window U-value, the mass of interior furnishings and supply fan static pressure.     

杭州市公共建筑能耗调查与分析

通过对杭州市公共建筑能耗现状的调查,概述了杭州市公共建筑能耗现状,并针对写字楼,宾馆酒店,商场等类型公共建筑进行了能耗分析和评价,同时为进一步加强杭州市公共建筑节能工作提出了建议.     

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.     

大型办公建筑照明及插座系统电耗逐时使用率聚类分析

逐时使用率对于预测办公建筑照明与插座系统电耗,以及核定节能改造的节能量有十分重要的意义。选取重庆17幢办公建筑作为研究对象,根据建筑全年逐时照明与插座系统的实测电耗数据,计算各建筑全年每个工作日24h的逐时使用率。利用聚类分析方法,根据日逐时使用率的不同,将办公建筑快速分为3类。根据是否经常加班以及午休时是否关闭部分用电设备,可以快速判断办公建筑属于哪一分类。最后对3类建筑分时段计算典型逐时使用率,便于实际应用中快速查询。     

基于ANN的绿色办公建筑HVAC系统运行能耗预测

办公建筑中暖通空调系统(HVAC系统)的运行能耗占总能耗比例较高。随着绿色建筑的大力推广,准确预测绿色办公建筑HVAC系统能耗是建筑运行优化的关键。研究以天津市某绿色办公建筑为研究对象,根据绿色办公建筑G中的HVAC系统——地源热泵系统和空调通风系统能耗的实际监测数据,建立了基于人工神经网络的能耗预测模型。研究结果表明,建立的分类多层感知器神经网络预测模型预测精度最好,仅基于气象参数及时间能够精确的预测建筑HVAC系统的小时能耗,为我国绿色办公建筑的设计和运行优化提供科学支持。     

办公建筑提高夏季空调设定温度对建筑能耗的影响

提高夏季空调设定温度对不同类型办公建筑能耗的影响程度不同。以北京地区办公建筑为研究对象,分别对3种空调设定温度下的建筑能耗进行了模拟。针对大、中、小型办公建筑,分析了影响其节能量的主要因素,并提出了相应的改善措施。     

Green roofs; building energy savings and the potential for retrofit

Green roofs are a passive cooling technique that stop incoming solar radiation from reaching the building structure below. Many studies have been conducted over the past 10 years to consider the potential building energy benefits of green roofs and shown that they can offer benefits in winter heating reduction as well as summer cooling.This paper reviews the current literature and highlights the situations in which the greatest building energy savings can be made. Older buildings with poor existing insulation are deemed to benefit most from a green roof as current building regulations require such high levels of insulation that green roofs are seen to hardly affect annual building energy consumption.As over half of the existing UK building stock was built before any roof insulation was required, it is older buildings that will benefit most from green roofs. The case for retrofitting existing buildings is therefore reviewed and it is found there is strong potential for green roof retrofit in the UK.     

Linking BIM and Design of Experiments to balance architectural and technical design factors for energy performance

To transform the existing energy systems towards renewable energy sources, buildings need to use less energy, use energy more efficiently and harness local renewable energy sources. For the design of energy-efficient buildings, building energy simulation of varying sophistication is commonly employed. Types of simulations range from simple, static calculations to sophisticated dynamic simulation. Especially for building retrofit many assumptions on construction, material etc. have to be taken, which increases the uncertainty of simulation results. In conjunction with simulation, methods of Building Performance Optimization are increasingly employed. They are able to identify best performing designs however do not provide insights on the mechanisms and interdependencies of the different design factors, which are most valuable to make informed design decisions. We present a methodology that aims to provide a better understanding and create knowledge about the influence and interactions of different architectural and technical design factors on building energy performance of a specific design task. For this purpose, we introduce Design of Experiments (DoE) in an integrated design workflow using the Design Performance Viewer (DPV) toolset, combining Building Information Modeling (BIM), distributed dynamic simulation and statistical analysis of the extensive simulation results. The experiments created using the methodology allow to identify the strength of effects and interactions of different design factors on selected performance indicators. We apply the methodology on an office retrofit case, introducing a factor scatterplot for result visualization, development and comparison of retrofit strategies. We further evaluate its potential to identify high performing strategies while balancing architectural and technical factors and their impact on energy performance.     

Virtual Building Dataset for energy and indoor thermal comfort benchmarking of office buildings in Greece

The knowledge of building stock energy data of a country is a very significant tool for energy benchmarks establishment, energy rating procedures and building classification boundaries determination, according to the Directive 2002/91/EC and its implementation in EU Member States. The lack of building energy databases in many EU Countries, including Greece, and the difficulties of collecting them lead to the investigation of other potential solutions. The aim of this paper is to present a method of a Virtual Building Dataset (VBD) creation for office buildings in Greece. The philosophy of VBD is based on the creation and simulation of random office buildings that could be found or built in Greece, taking into account the Greek constructional and operational characteristics of office buildings and Greek legislation. The VBD consists of 30,000 buildings (10,000 in each climatic zone) with their detailed constructional and operational data and of their simulation outputs: the annual specific energy consumption for heating, cooling, artificial lighting, office equipment and an indoor thermal comfort indicator. Based on VBD results the energy and indoor thermal comfort benchmarks for office building sector in Greece are assessed and presented.     

济南地区某办公楼能耗模拟与节能研究

如今,办公建筑已成为社会的主要建筑类型。办公建筑也随之成为了能耗大户,如何对办公建筑降低能耗成为如今的必要思考。本文选取济南地区某一办公建筑,利用DeST软件对其能耗进行模拟,并与参照建筑进行对比,得到济南地区办公建筑降低能耗的实用规律,为今后办公建筑降低能耗,节能减排提供参考。