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%.     

Energy saving with passive climate control methods in Spanish office buildings

This work comprises case studies of passive indoor climate control techniques, applied to a number of office buildings in Spain. The main objective of the work was to evaluate the effects of using indoor permeable coverings on energy savings, for the same indoor thermal comfort conditions. Previous studies have shown that permeable coverings will lead to optimal indoor comfort conditions, which depend on maximum and minimum monthly mean outdoor temperature and relative humidity values. This work shows that, both in summer and winter, indoor energy consumption decreases with the permeability of coverings. An energy saving potential of 3 kWh/m² per year may be achieved, which leads to the possibility of replacing mechanical HVAC by passive methods in mild climates, such as in Spain and Portugal.     

Peak load characteristics of Sydney office buildings and policy recommendations for peak load reduction

Growth in peak period electricity demand has driven the requirement for a significant expansion of Sydney's electricity network. Energy efficiency and demand management activities in office buildings may be an alternative to electricity network augmentation, with significant economic and environmental benefits. This paper identifies and characterises trends in electricity peak demand in Sydney's office buildings, comparing a range of high and low energy consuming buildings. The paper assesses the potential for energy efficiency and demand management strategies in office buildings to reduce peak loads and hence defer electricity network augmentation. Base building electricity load data was analysed for a sample of 25 Sydney office buildings, along with Sydney electricity substation and temperature data. Peak loads for buildings with best practice energy performance were found to be 26% lower than for buildings with average energy performance, while annual electricity consumption was 57% lower. With these findings, this paper has assessed the effectiveness of current energy efficiency policy for peak demand management and has recommended strengthening energy efficiency policies in order to capture coincidental peak load reductions, as well as new policies specifically targeting peak demand management. It was found that these measures could offer significant potential to defer network investment.     

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.     

Code compliance of fully glazed tall office buildings in hot climate

In this research, the effect of glazing type and other energy conservation measures on the peak power demand of air-conditioning (AC) systems is investigated for tall and fully glazed government and private office buildings. The EnergyPlus building simulation program is used in the analysis assuming climate conditions similar to that experienced in hot countries of the Arabian Gulf, such as Kuwait. The main objective of the investigation is to meet the limits stipulated in the mandatory Kuwaiti code of practice for energy conservation, with respect to peak AC demand, for both air-cooled and water-cooled AC systems. It is found that for government office buildings with air-cooled AC system, the code limit of 70 W/m² for the AC peak power is met when tint low-e glazing is used with either heat recovery units or with AC systems with higher coefficient of performance (COP); whereas for private office buildings, the limit can be met when using a number of conservation measures. Overall, the water-cooled AC system showed better performance even though the code limit is 50 W/m² which is mainly due to the higher COP values achievable with such AC systems.     

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.     

智能照明控制系统在办公建筑中的应用

介绍了智能照明控制系统的发展背景和优势,在此基础上结合某报业集团办公楼的电气设计,阐述了智能照明控制系统在办公类建筑中的应用,指出智能照明控制系统具有灵活方便,降低成本,绿色节能的特点,以期推广应用。     

综合高层办公楼发展历史回顾

首先回顾了世界高层建筑的发展历史,然后又回顾了综合、高层办公楼在国内的发展历史,分析了它的优越性以及带给人们的负面影响,发挥优点,克服缺点,以使高层建筑能为人类创造美好的生活与工作环境而服务。     

超高层五星级酒店和办公综合体绿色建筑研究

以昆钢科技大厦(索菲特酒店)为例,介绍了建筑、结构和机电专业在应对绿色建筑时的各种设计策略,探讨了绿色建筑技术在超高层五星级酒店和办公综合体中应用的各种可能性,为绿色建筑技术的推广指明了方向。     

Adaptive reuse of office buildings into housing: opportunities and risks

One way of adapting and reusing vacant office buildings is conversion into housing. Former research has shown possibilities for this type of conversion, and has delivered instruments for determining the conversion potential of vacant offices. Although adaptation and renovation of outdated offices can prove to be a successful property (real estate) strategy, conversions into housing still only occur on a small scale. There are several reasons for this, including uncertainty about financial feasibility and little knowledge about the opportunities and risks of building conversions. A meta-study of the conversion of 15 office buildings into housing in the Netherlands is used to reveal the drivers for office-to-housing conversions as well as the opportunities and risks that arise in the conversion process. The findings show that various legal, financial, technical, functional and architectonic issues define the opportunities and risks of building conversions. These insights can be used to support the decision-making processes for dealing with vacant office buildings in order to minimize the risks and increase the opportunities.     

天津市办公建筑能耗调研及分析

对天津市552个办公建筑进行了调研,获得了建筑概况、耗电量等基础数据,筛选确定了24个样本建筑。分析计算得出,样本建筑2010年单位面积年总耗电量为26.79～125.45kW.h/(m2.a),平均值为64.25kW.h/(m2.a);2010年供暖期单位供暖面积耗热量为0.21～0.37GJ/(m2.a),平均耗热量为0.27GJ/(m2.a)。调研结果表明,天津市办公建筑存在较多问题,建筑能耗较大,具有较大的建筑节能空间。     

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.     

Comparison of low-energy office buildings in summer using different thermal comfort criteria

Sustainable low-energy office buildings attempt to harness the buildings architecture and physics to provide a high quality working environment with the least possible primary energy consumption. A promising approach to condition those buildings in summer employs the utilization of the building's thermal storage activated by natural heat sinks (e.g., ambient air, ground water or soil) through night ventilation or thermally activated building systems (TABS). However, a certain room temperature cannot be guaranteed as occupants may influence the room energy balance by window opening, internal heat gains or sun shading control. Between 2001 and 2005, monitoring campaigns were carried out over 2 or 3 years in 12 low-energy office buildings which are located in three different summer climate zones in Germany. These climate zones are defined as summer-cool, moderate and summer-hot. The weather at the building site and the room temperatures in several office rooms were monitored by different scientific teams. The raw data are processed for data evaluation using a sophisticated method to remove errors and outliers from the database and to identify the time of occupancy. The comfort in all office rooms in each building is evaluated separately. For data presentation, these separate comfort votes per office room are averaged using the median instead of the arithmetic mean in order not to overestimate extremely cold or hot room temperatures. A comfort evaluation in these 12 low-energy office buildings indicates clearly, that buildings which use only natural heat sinks for cooling provide good thermal comfort during typical and warm summer periods in Germany. However, long heat waves such as during the extreme European summer of 2003 overstrain passively cooled buildings with air-driven cooling concepts in terms of thermal comfort.     

Renovation of existing office buildings in regard to energy economy: An example from Ankara,Turkey

Unit energy consumption of existing buildings in Turkey is excessive. While average energy consumption of residential buildings in Europe is 100 kWh/m² per year, it is about 200 kWh/m² per year in Turkey. The principle reason for this, is that there was not any regulation on thermal insulation issues until recent years. However, the fiscal value of total energy consumption in residential buildings is about $2.5 billion. Recent research has shown that 40% of this energy consumption could be saved, provided that using energy efficiently. Furthermore, every reduction in energy-usage has a significant influence on environmental protection and CO₂ emissions. This study has focused on energy efficiency in a building of public sector that had been inaugurated in 1988 in Ankara. During the pre-investigative step, it has been determined that 47% of total energy consumption of the building could be saved.     

武汉写字楼的能源管理与节能改造分析

根据2007年武汉市能源审计结果,分析了写字楼的能源管理现状.对某写字楼进行了能耗模拟和节能改造模拟.能耗模拟结果表明,机组选型偏大,系统运行调节存在问题.建议提高系统综合能效比、实施照明控制和安装外遮阳;能耗模拟要考虑周边建筑的阴影.     

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.     

我国北方办公建筑能耗特点及节能设计措施

通过对我国北方气候特点的分析,结合办公建筑使用特点,总结出我国北方办公建筑的能耗特点,并分析了当前我国北方办公建筑节能方面存在的问题,针对问题从规划建筑设计、建筑节能技术、合同能源管理几个方面讨论了适宜我国北方办公建筑节能的措施,以减少办公建筑能耗,推进社会持续发展。     

Energy efficiency optimization of combined ventilation systems in livestock buildings

Good ventilation system in livestock buildings is necessary for removing excess moisture and heat and for improving building environment in general. Natural ventilation does not require energy consumption and on the other hand, animals would not be affected by electrical power failures. Because natural ventilation depends largely on temperature difference between inside and outside air and wind velocity and direction it is very important in early stages of building design to provide orientation and accurate opening areas. Numerical simulation of natural ventilation and computation of fluid dynamics in livestock buildings can be usefully integrated in whole ventilation system optimization and related energy consumption decrease. Even in mechanical system ventilation, from flow field obtained in numerical simulation it is possible to optimize these systems. CFD analysis is generally restricted to the study of buildings’ environment flows and space study, and the designer must supply boundary conditions in the form of external and internal buildings’ envelope/wall surface conditions. Finally, the needs for further research and engineering development are outlined.     

现代办公建筑内部空间分析

针对现代办公建筑内部空间设计进行了探讨,从内部空间组成入手,分别阐述了办公建筑公共空间,办公空间及交通空间的设计要点及目标,指出应注重人性化设计,科学合理布置,以营造优美舒适的办公环境。