Modeling the energy retrofit decision in commercial office buildings

Retrofitting existing buildings has emerged as a primary strategy for reducing energy use and carbon emissions, both nationally and in cities. Despite the increasing awareness of retrofitting opportunities and a growing portfolio of successful case studies, little is known about the decision-making processes of building owners and asset managers with respect to energy efficiency investments. Specifically, the research presented here examines the effects of ownership type, tenant demand, and real estate market location on building energy retrofit decisions in the commercial office sector. This paper uses an original, detailed survey of asset managers of 763 office buildings in nineteen cities sampled from the CBRE, Inc. portfolio. Controlling for various building characteristics, the results demonstrate that ownership type and local market do, in fact, influence the retrofit decision.Overall, this analysis provides new evidence for the importance of understanding ownership type and the varying motivations of differing types of owners in building energy efficiency investment decisions. The findings of both the survey analysis and the predictive model demonstrate additional support for the targeting of energy efficiency incentives and outreach based on ownership entity, local market conditions, and specific physical building characteristics.     

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.     

A cost effective approach to design of energy efficient residential buildings

The objective of this study is to identify cost-optimal efficiency packages at several levels of building energy savings. A two-story residential building located in Jordan is selected as a case study. DesignBuilder software is used to predict the annual energy usage of a two-story residence in Irbid, Jordan. Real-time experimental data from a single isolated controlled room was used to verify the proposed model. In addition to energy analysis, the economic, environmental, and social benefits of the proposed design have been investigated. The sequential search optimization approach is used to estimate the minimum cost of the building while considering various design scenarios. In addition, the impact of various energy conservation techniques on residential buildings is assessed, and the payback period for each program is calculated. Ultimately, the optimal combination of design to achieve energy efficiency measures has been identified in several climate regions. The simulations results predict that the annual electricity consumption can be reduced up to 50% if the proper combinations of energy conservation measures are selected at the lowest cost. The payback period is 9.3 years. Finally, energy efficiency measures can lead to a total of 9470 jobs/year job opportunities.The study provide practical framework to link between energy performance criteria and economic goals of building. Linking the energy performance requirements to economic targets provides guidelines for homeowners, contractors, and policymakers for making a suitable decision regarding the retrofitting of existing residential buildings. The study focuses on developing new methodologies that support minimizing costs during a building's lifecycle while maximizing environmental benefits which can not be identified by a series of parametric analyses using individual energy-efficient measures.     

A cost effective approach to design of energy efficient residential buildings

The objective of this study is to identify cost-optimal efficiency packages at several levels of building energy savings.A two-story residential building locate...     

Energy savings modelling of re-tuning energy conservation measures in large office buildings

Today, many large commercial buildings use building automation systems to manage a wide range of equipment. This paper investigates the energy savings potential of several common heating, ventilation, and air conditioning (HVAC) system re-tuning measures on a typical large office building using the EnergyPlus software. Individual re-tuning measures simulated include automatic schedule adjustments, damper minimum flow adjustments, thermostat adjustments, as well as dynamic resets to static pressure, supply-air temperature, condenser chilled- and hot-water temperatures, and chilled and hot water differential pressure set points. All individual measures and combinations were simulated in 16 locations representative of different climates in the USA. Many of the demand-side individual measures were capable of reducing annual HVAC energy consumption by over 20% in most cities. Supply-side measures affecting HVAC plant conditions were only modestly successful (less than 5% annual HVAC energy savings). Some of the combinations revealed between 35% and 75% HVAC energy savings.     

Impact of electricity rate structures on energy cost savings of pre-cooling controls for office buildings

This paper summarizes the results of a series of parametric analyses performed to evaluate the impact of key design and operating conditions on the effectiveness of pre-cooling control strategies for reducing peak demand and overall energy costs for office buildings. The analyses were carried out using EnergyPlus, a whole building energy simulation program. The effects of various parameters were considered in the analysis including building location, mass level, pre-cooling control strategy, and time-of-use utility rate.     

Life cycle cost implications of energy efficiency measures in new residential buildings

The importance of the built environment from an environmental impact and energy use perspective is well established. High thermal efficiency of the constructed building envelope is a key strategy in the design and construction of buildings which limit use of active space conditioning systems. Australia's current housing stock is thermally poor and national energy performance standards are relatively weak when benchmarked against international best practice. A lack of data has impeded the policy debate and a significant gap in analysis remains a lack of empirical research into the life-cycle cost implications of increased building thermal efficiency, particularly for residential buildings. This paper applies an integrated thermal modeling, life cycle costing approach to an extensive sample of dominant house designs to investigate life cycle costs in a cool temperate climate, Melbourne Victoria. Empirical analysis provides new insights into lifetime costs and environmental savings for volume housing design options and identifies sensitive factors. Results suggest that the most cost-effective building design is always more energy efficient than the current energy code requirements, for the full time-horizon considered. Findings have significant policy implications, particularly in view of present debates which frequently present higher energy efficiency standards as prohibitive from a costs perspective.     

Simplified energy analysis methodology for commercial buildings

Commercial building energy analyses may be used for new building design, energy end use forecasting and energy audit calculations. Many building simulation programs, such as DOE 2.1A or BLAST, are quite complex and must be run by specialists on main frame computers. A simplified method of commercial building energy analysis has been developed that utilizes a database of previous DOE 2.1A simulations to predict the outcome of other simulations. We have applied this methodology to an office building in one climate region and have found that it predicts heating, cooling, and total energy use very accurately. The main advantage of this methodology is that less specialized skill is required and only a microcomputer is needed to perform the analyses. Therefore, energy analyses can be done cheaply and quickly.     

A new methodology for the design of low energy buildings

The Kyoto protocol binded the developed countries to reduce the greenhouse gas emissions at least by 5% by 2008-2012 in order to tackle global warming and climate change. Some of the measures of the governments to achieve this goal are to promote new buildings construction and to retrofit existing buildings while satisfying low energy criteria. This means improving energy efficiency of buildings and energy systems, developing sustainable building concepts and promoting renewable energy sources.The design of a low energy building requires parametric studies via simulation tools in order to optimize the design of the building envelope and HVAC systems. These studies are often complex and time consuming due to a large number of parameters to consider. Hence, this paper aims to set up a methodology that simplifies parametrical studies during the design process of a low energy building. The methodology is based on the Design of Experiments (DOE) method which is a statistical method widely used in industry to perform parametric studies that reduces the required number of experiments.     

Life-cycle carbon and cost analysis of energy efficiency measures in new commercial buildings

Energy efficiency in new building construction has become a key target to lower nation-wide energy use. The goals of this paper are to estimate life-cycle energy savings, carbon emission reduction, and cost-effectiveness of energy efficiency measures in new commercial buildings using an integrated design approach, and estimate the implications from a cost on energy-based carbon emissions. A total of 576 energy simulations are run for 12 prototypical buildings in 16 cities, with 3 building designs for each building-location combination. Simulated energy consumption and building cost databases are used to determine the life-cycle cost-effectiveness and carbon emissions of each design. The results show conventional energy efficiency technologies can be used to decrease energy use in new commercial buildings by 20-30% on average and up to over 40% for some building types and locations. These reductions can often be done at negative life-cycle costs because the improved efficiencies allow the installation of smaller, cheaper HVAC equipment. These improvements not only save money and energy, but reduce a building’s carbon footprint by 16% on average. A cost on carbon emissions from energy use increases the return on energy efficiency investments because energy is more expensive, making some cost-ineffective projects economically feasible.     

A systematic methodology for optimising the energy performance of buildings in Bahrain

Today, a great deal of effort is ongoing all over the world to find methods for optimising the energy performance of buildings. Such efforts can be seen in the European Energy Performance of Building Directive (EPBD). This directive aims to ensure energy saving and CO₂ emission reduction without compromising the local conditions and people's comfort. In the Gulf States, however, there is a need for such methods due to their economic and environmental benefits. This study introduces a simple but reliable methodology for optimising building energy performance in Bahrain. The methodology is based on building management systems (monitoring, analysing and targeting future performance), simulation tools and other technologies. This methodology was implemented using Visual DOE and was directly related to collectively gathered data gained form experimental works and practical applications. By means of the introduced methodology, energy consumption was obtained together with energy cost and CO₂ emissions. The applicability of this methodology was demonstrated through optimising a case office building in Bahrain.     

建筑的综合节能措施

建筑工程由土建和设备两大部分组成,它们构成了一个完整的体系工程,所以建筑的节能也应是一个完整体系工程的节能,因此,对建筑节能应取综合性的节能措施。 一、建筑的平面布置及体型的节能 建筑平面布置应满足两点,其一是建筑在冬季应尽可能多的接收太阳能,二是在夏季尽可能少的接收太阳能。一般建筑物的朝向南北向较东西向更节能;节能建筑应采取节能体形,人们传统的观念认为圆形、正方形建筑节能,其实这是一个传统的错误,因为建筑物的周围环境不对称,以及建筑的围护结构不对称,所以最佳节能体型并非圆形和正方形。最佳的节能体…     

Effects of energy conversation measures the life cycle cost of Kuwaiti residential buildings

With increasing energy supply costs, considerable interest is now being shown in introducing energy conservation measures in the construction of residential houses. Kuwait, like any other country, is becoming increasingly aware of the value of conserving its natural fuel resources. For seven months of the year the temperatures in Kuwait are above comfort level; consequently 60% of its consumed energy is used for space cooling.The effects of energy conservation measures are evaluated for a typical two-storey residential building for two design alternatives. The analysis shows that adding insulation material to the walls and roof will reduce owning and operating costs by 173 Kuwaiti Dinars (K.D.)¹ annually for the houseowner, while the saving to the Government will be 1982 K.D. annually for each such housing unit.If additional measures are introduced, such as double glazing of windows, shading devices, use of air-to-air heat exchangers and tight construction to reduce infiltration, the owning and operating costs will be reduced by 870 K.D. annually for the houseowner and an annual saving of 4287 K.D. will be realized for the Government. These figures are based on a 10% discount rate.     

Climate models for the assessment of office buildings energy performance

In the last few years many advanced computer packages, characterised by a considerable integration between thermal and visual aspects, were developed to support designers and to study building energy performance, innovative materials and daylight control strategies and systems. These packages, as a function of their complexity and final use, require different types of outdoor data, ranging from monthly (MTD) or seasonal typical days (STD) to more complex typical meteorological years (TMY).Both the deterministic and the stochastic components of outdoor data are present in TMYs, while MTDs and STDs take into account only the deterministic component. The use of MTDs or STDs produces a sensible reduction of the calculation time, above all appreciable in the first phase of the building design process, although it introduces an element of uncertainty in simulation results due to the absence of the stochastic component of outdoor data. This uncertainty is not easily predictable, as reported by many authors.The aim of the present work is to investigate the influence of the stochastic component of meteorological data in evaluating office building energy performance in Mediterranean climate. The study is performed by an advanced numerical computer package, Integrated ENergy Use Simulation (IENUS), which can process different types of climatic data. Different typologies, systems and space managements are investigated.     

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.     

Modular energy cost optimization for buildings with integrated microgrid

Buildings are becoming suitable for application of sophisticated energy management approaches to increase their energy efficiency and possibly turn them into active energy market participants.The paper proposes a modular coordination mechanism between building zones comfort control and building microgrid energy flows control based on model predictive control. The approach opens possibilities to modularly coordinate technologically heterogeneous building subsystems for economically-optimal operation under user comfort constraints. The imposed modularity is based on a simple interface for exchanging building consumption and microgrid energyprice profiles. This is a key element for technology separation,replication and up-scaling towards the levels of smart grids and smart cities where buildings play active roles in energy management. The proposed coordination mechanism is presented in a comprehensive realistic case study of maintaining comfort in an office building with integrated microgrid. The approach stands out with significant performance improvements compared to various non-coordinated predictive control schemes and baseline controllers. Results give detailed information about yearly cost-effectiveness of the considered configurations,which are suitable for deployment as short-and long-term zero-energy building investments.     

高层建筑的消防灭火救援有效措施研究

经济的飞速发展,使得建筑行业呈现出快速发展的势头,高层建筑的数量日渐增多,与之相关的消防火灾救援问题备受瞩目.文章重点概述了高层建筑火灾的具体成因,同时结合对高层建筑火灾基本特点详细的判断,对高层建筑消防灭火救援的难点重点进行了阐述,依照要点深入研究,提供建议和参考意见,希望对高层建筑消防灭火工作有所帮助.     

住宅能耗现状及节能措施

简述了我国住宅建设的能耗现状及其节能潜力,提出四条可行的有效的节能措施。     

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。     

浅议如何有效控制建设工程造价

对如何有效地控制建设工程造价进行了分析,根据建设工程造价的六大特点,提出了控制工程造价要抓好的三个重要环节,以求把有效的资金合理使用,取得最佳的工程投资效益。