1、 Om Taneja is Director of Manhattan Service Center, US General Services Administration, Region 2, New York City Measures for Maintaining Low Energy use in Commercial Buildings over their Life-Cycle By Om Taneja, Ph. D., P.E. ABSTRACT The challenge that sustainable buildings movement faces is , “how
2、to maintain the intended sustainable performance with regards to low energy use, indoor comfort and projected operating costs savings over the long term use of the building” Rapid decline in sustainable performance of a few high-profile buildings affects credibility of the High Performance buildings
3、 initiatives, reinforces doubts amongst climate-change non-believers and slows down the enthusiasm of the investors. Examining the lifecycle performance and costs, raising the awareness of building owners and tenants, adopting the best operational and maintenance practices by trained and skilled ope
4、rating staff, and incorporating measurements, verification and automation technologies to automatically track and optimize the performance of all key buildings systems needs to become an essential part of property management culture to avoid pitfalls. Emergence of Building Energy Labeling Program an
5、d Building Information modeling techniques coupled with energy use sub- metering can alert of issues during commissioning, building occupancy, tenant-fit ups , building-use changes or of decline in performance due to poor operations and maintenance management. Building Heating, Ventilation and Air C
6、onditioning systems are significant users of energy as well as their operations and maintenance impacts the health and security of tenants. Therefore, proper design, configuration, commissioning, operations and maintenance of such systems continues to offer opportunities for reducing the emission of
7、 greenhouse gases, and any lapses in monitoring and correcting deficiencies creates shortfall in sustainable performance over the life of a building. As the largest single landlord in the United States, the Federal Government oversees about 500,000 federal buildings. With additional resources being
8、made available under the Recovery Act funding, new tools are emerging to allow monitoring and control of energy use. This paper outlines various qualitative and quantitative measures that can be practiced to improve and sustain performance of all building systems and infrastructure elements. Amongst
9、 all the measures, having trained and motivated operations and maintenance staff involved from concepts stage through design, construction, commissioning, and operations not only facilitates meeting the original design intent, but also allows to make adaptive changes with changes in occupancy , func
10、tionality, codes, standards or security requirements. Such general practices can assure sustenance of energy and environmental performance over the life cycle of systems and buildings. This paper also emphasizes how industry professional and trade organizations can guide towards standards and guidel
11、ines that can be more easily assimilated by the operations and maintenance staff and can help modify human behavior towards not only designing, but maintaining a more socially and environmentally responsible built-environment. INTRODUCTION The world needs ever increasing energy supplies to sustain e
12、conomic growth and development. Soaring worldwide demand for energy is driving climate-altering greenhouse gas emissions dangerously higher. NASA says that the January-through-June period, 2010 was the hottest globally since measurements began in 1880, and one of the reasons for this is due to incre
13、asing greenhouse gas emissions. Even though there is greater awareness, we continue to be nonchalant about slowly-encroaching dangers such as the prospect of rising carbon emissions devastating the planet earth and our way of life. Even as investments grow in new “clean“ energy sources, existing tec
14、hnologies to lower waste and reduce energy use are being neglected. According to International Energy agency (IEA) (1), World Energy Outlook 2008, “The worlds energy system is at crossroads. Current global trends in energy supply and consumption are unsustainable environmentally, economically, socia
15、lly. Preventing catastrophic and irreversible damage to the global climate ultimately requires a major de-carbonization of the world energy sources, heavy investments in more energy efficient equipment and appliances and changing our behavior in daily lives. World primary energy demand continues to
16、grow by 1.6% per year on average, a projected increase LV-11-C065 2011 ASHRAE 5252011. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions, Volume 117, Part 1. For personal use only. Additional reproduction, distribution,
17、 or transmission in either print or digital form is not permitted without ASHRAES prior written permission.of 45% between 2006-2030. Trends point to continuing growth in emissions of CO2 and other greenhouse gases. This scenario puts us on a course of doubling the concentration of greenhouse gases i
18、n the atmosphere by the end of this century, entailing a projected global average temperature increase of up to 6 degrees centigrade. Encouraging signs are certainly on the horizon, reports the IEAs newly released Energy Technology Perspectives 2010: Scenarios Emerging Green Codes Compliance require
19、ments by many municipalities, Federal Agencies, and risk-aversion motivated private companies. Greenhouse Gases are the targeted culprit - Scientific knowledge and growing consensus regarding release of greenhouse gases, global warming and climatic changes resulting from increasing levels of energy
20、use is starting to drive all stakeholders towards high-performance net-zero carbon footprint buildings initiatives. It is envisioned that the economy of the 21stcentury will be renewed and built on pillars of sustainability(10). Green Procurement policies for environmentally friendly materials - Bui
21、ldings account for 40% of all materials harvested from environment. Building Teams should be able to specify 90-95% of the basic green products and materials they need for their jobs, usually at prices competitive with conventional products. 2011 ASHRAE 527GAPS BETWEEN BUILDINGS EXPECTATIONS Level I
22、I- Energy Survey ASHRAE Energy Labeling (Building eQ) Program or “Experience Exchange Reports” published by the Building Owners and Reference 14) Install Building Management Systems that are adaptive to building use, occupancy and weather changes. Such systems monitor, report and adjust to control
23、energy use and alert to take action when performance starts to decline. Judicious use of Select Prescriptive and Performance Based Energy Efficiency Acts, Codes The Green Standard - ANSI/ASHRAE/USGBC/IES Standard 189.1, Standard for the Design of High Performance, Green Buildings Except Low-Rise Res
24、idential Buildings, as an alternate path of compliance. Standard 189.1 and ASHRAE Advanced Energy Design Guides (AEDG) facilitate high performance buildings benchmarking, and improved design and operations 6PBS Environment ProgramFIGURE 3 US General Services Administration Energy b.) use of sustaina
25、ble operations and maintenance practices within the appropriate Environmental Management System (EMS); c.) assessment of existing conditions and operational procedures of the building and major building systems and identify areas for improvement, d.) establish operational performance goals for energ
26、y, water, material use and recycling, and indoor environmental quality, e.) ensure incorporation of these goals throughout the remaining lifecycle of the building, and f.) incorporate a building management plan to ensure that operating decisions and tenant education are carried out with regard to in
27、tegrated, sustainable building operations and maintenance, augmenting building operations and maintenance as needed using occupant feedback on work space satisfaction. Building Information Modeling - Building Information Model (BIM) can be a powerful tool to plan, project, track, adjust and enhance
28、buildings design, construction and operations throughout the life-cycle of a building, from initial concept through design, construction, operations and future renovations. The primary benefits of BIM are due to its capabilities of capturing, organizing, integrating, maintaining the vast amount of b
29、uilding data required to conceptualize, plan, design, construct, operate, maintain, adapt , renovate and possibly decommission the building in an environmentally friendly manner. BIM fosters collaboration amongst team members more effectively than traditional approaches. A BIM can become a living, h
30、istorical database of every material, component, assembly and systems used in the building for global project management. Raising Awareness Of Occupants - Tenants are not always made aware of how their use of spaces and equipment affect the energy use and environment and without their active partici
31、pation and commitments, some of their actions inadvertently negate the benefits of high performance design elements. Figure 3 demonstrates how an individual interacts in the environment management process. Encouraging tenants not to use space heaters and fans, and to turn off equipment during off ho
32、urs, making sure to shutting off lights, power down everything - such as computers, monitors, copiers, kitchen equipment and task lights, can significantly reduce plug loads. In U.S. companies alone, more than $1 billion a year is wasted on electricity for computer monitors that are left on when the
33、y shouldnt be. Such activities can change occupant behavior and can help save between 3.5% to 15.2% of energy(12). Keeping Score: Getting to an Appropriate Set of Metrics (16)- Many design teams do not include plug, process and tenant improvements loads in projecting energy efficiency targets. These
34、 details need to be considered when setting goals and reporting both projected and actual energy performance. Understanding the metrics for building environmental performance, and then measuring performance against those “yardsticks” is key to performance improvement. OPERATIONS & MAINTENANCE Operat
35、ional Efficiency represents the life-cycle cost-effective mix of preventive, predictive, and reliability-centered maintenance technologies, coupled with equipment calibration, tracking, and computerized maintenance management capabilities all targeting reliability, safety, occupant comfort, and syst
36、em efficiency. Federal Energy Management Program 17, 18(FEMP) has estimated that O&M programs targeting energy efficiency can save 5% to 20% on energy bills without a significant capital investment. Just for federal facilities, operational efficiencies can lower energy costs between 175 Million to 7
37、00 million with concomitant reductions in release of Greenhouse gases. From small to large sites, these savings can represent thousands to hundreds-of-thousands of dollars each year, and many can be achieved with minimal cash outlays. For US Government Buildings, it is estimated that O&M programs ta
38、rgeting energy efficiency not only have the potential for significant cost and energy/resource savings, but also deliver other important benefits, when O&M programs keep systems operating at their peak “operational efficiency“ , such as: A well-functioning O&M program is a safe O&M program. Equipmen
39、t is maintained properly mitigating any potential hazard arising from deferred maintenance. Proper O&M reduces the risks associated with the development of dangerous and costly IAQ situations. Properly performed O&M ensures that the design life expectancy of equipment will be achieved or exceeded an
40、d unanticipated failures posing business risks are minimized. Buildings with an effective O&M program more easily comply with Federal laws such as the Clean Air Act and the Clean Water Act. A well functioning O&M program means not always answering complaints. Rather, it is proactive in its response
41、and corrects situations before they become problems and keeps occupants satisfied. 530 ASHRAE TransactionsMany high performance buildings are designed with state of the art efficient and complex equipment, particularly controls, which often require improvements and iterative adjustments over multipl
42、e seasons to ultimately operate as designed. O&M staff must be trained and motivated to keep up with such adjustments. Training of O&M Staff & Accountability - For proper use of metered information and effective operations and maintenance of state-of-the-art equipment and controls, industry needs bu
43、dget allocations for aggressive, structured training programs for operations and maintenance staff. Performance ratings of facility managers must include the training requirements and associated certification that prepares them to become skilled in energy efficient operations and maintenance program
44、s. There is a spirit of cooperation amongst professional organizations, such as ASHRAE, BOMA, USGBC, Trade Unions and Property Managers to develop customized training programs for the O&M staff that prepares them to operate and maintain high performance buildings in a results-driven manner. CONCLUSI
45、ON Development of land, design, construction and operation of buildings is a significant cause of release of greenhouse gases and affects safety, wellbeing and productivity of people who live, work or enjoy in built-environment (5,20).With Society now demanding net zero energy buildings, it is timel
46、y and socially responsible to pursue an integrated holistic approach that considers the impacts on environment, costs and quality over all phases in the life of a building and its chillers/HVAC and associated support systems rather than as a snapshot (20)For this to occur, we must first determine wh
47、at we have, how we got there and how divergent issues can be consolidated to facilitate a net high performance result. That makes it important to audit, meter, monitor, track, compare and from such data, deduce directions for implementing various justified energy efficiency measures. To make a diffe
48、rence, we need to involve all stakeholders, employ different prescriptive, modeling and analytical tools, periodically perform retro-commissioning and be prepared to accommodate and adapt systems to changes in use, occupancy, weather or building process or plug loads. The more in-depth understanding
49、 we have of factors affecting the environment, the more likely there will be progress towards sustainable and high performance green buildings. It is time to heed to the time-tested adage, “Unless we change our direction, we are likely to end up where we are going” Chinese Proverb There is hope since there is rising awareness of energy and environmental issues. Several major cities have recently started to implement green building standards for both municipal and private construction projects. In addition, momentum is ga
