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3 Levers of Change The committee was asked to identify “approaches, tools, and technologies for overcoming identified challenges, barriers, and gaps in knowledge.” To do so, the committee devised levers of change, which it defined as “areas where federal agencies can leverage their resources to spur transformational actions and to make sustainability the preferred choice at all levels of decision making.” As noted in Chapter 1, the intent was not to recommend changes to the budget process or to directly confront other challenges, which was outside the scope of the study, but to find ways for federal agencies to overcome such bar- riers and achieve a range of objectives related to high-performance green buildings. The committee’s levers of change include • Systems-based thinking, • Portfolio-based facilities management, • Integrated work processes, • Procurement, contracting, and finance, • Communication and feedback for behavioral change, • Standards and guidelines, and • Technologies and tools. Although technologies are themselves a lever of change, they are best enabled through the other levers. All the levers are discussed below. SYSTEMS-BASED THINKING Systems-based, or holistic, thinking is aimed at bringing coherence and integration to an area of study to develop a better understanding of its nature and function. By focusing on an entire system, its components, and its ramifications, it becomes possible to look at how efficiently the system uses resources (financial, people, technology, materials, energy), to eliminate waste, and to manage environ- mental impacts. Effective systems-based thinking begins with the development of goals and objectives 27
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28 ACHIEVING HIGH-PERFORMANCE FEDERAL FACILITIES for the activity: The more ambitious the goals, the more innovative the solutions are likely to be. Execu- tive Order 13514 implies the use of systems-based thinking by directing federal agencies to develop a comprehensive inventory of greenhouse gas emissions associated with their supply chains. Systems-based thinking provides a life-cycle perspective that can overcome challenges posed by the budget process and by segmented work processes. It can help federal agencies meet ambitious mandates for the environment and quality of life by providing a more comprehensive understanding of the use of resources and their interrelationships. This understanding, in turn, can help agencies identify new ways to use resources, to substitute more sustainable resources, and to reduce their total use. In the process, agencies can find innovative solutions that will meet a variety of objectives as opposed to finding nar- rowly focused solutions with unintended consequences. The difference between conventional thinking and systems-based thinking is apparent when deter- mining how to reduce energy use. In conventional thinking, the use of electricity or natural gas is typically measured by meters at the point of delivery, and total energy for heating (gas for a furnace, electricity for furnace fans or hot water pumps), cooling (typically all electric), lighting (all electric), and appli- ances and computers is measured. Efforts to reduce energy use at the site typically focus on reducing the energy use per square foot of floor space and do not consider the source of energy. Energy savings are achieved by using equipment and appliances that are energy efficient—for example, Energy Star appli- ances and equipment and Federal Energy Management Program (FEMP)-designated electronic products. In systems-based thinking, the focus is on the source of the energy and how efficiently resources are used to produce and deliver energy to a building (Figure 3.1). For example, to produce electricity, coal is typically burned in a power plant to generate heat and to produce steam. The steam is then turned into mechanical energy to operate a turbine that generates electricity. In this process, about 65 percent of the original energy is typically lost in the form of waste heat emitted through smokestacks and cooling towers. As electricity moves along transmission lines to arrive at buildings, additional energy losses occur. As shown in Figure 3.1, by the time the electricity lights an incandescent bulb, the light produced represents less than 2 percent of the energy used to pro- duce it (NAS-NAE-NRC, 2008). In contrast, the direct delivery of natural gas to a building to produce light would be more efficient and less wasteful. fig 3-1.eps FIGURE 3.1 Applying systems-based thinking to the use of electricity. SOURCE: NAS-NAE-NRC, 2008. bitmap
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29 LEVERS OF CHANGE Figure 3.1 illustrates why there are two conventions—primary (or “source”) and delivered (or “site”)—for attributing energy to each kilowatt hour (kWh) of electricity delivered to the customer’s meter. (In the United States this energy is still usually measured in British thermal units, or Btu.) Figure 3.1 assumes that enough coal is burned to provide 1 Btu of heat to a power plant with an effi- ciency of 35 percent so the energy delivered to the transmission line is 0.35 Btu. This 0.35 Btu is then transmitted and delivered to the meter with an efficiency of 90 percent, for an overall system efficiency of E1 × E2 = 31.5 percent, which is often rounded off to one-third. Thus, 3 Btu of coal burned at the power plant deliver only 1 Btu to the customer’s site, and waste 2 Btu in cooling towers and hot stack gasses. For federal agencies and other organizations, the question to be answered is Which measure should be used when the goal is to minimize energy intensity per square foot of floor area? If a building is all electric this would not matter, but most buildings use both electricity and natural gas. The owner or customer pays not only for the delivered kWh but also for the wasted energy. From a systems point of view it makes better sense to use the primary fuel metric when setting energy-saving goals. Figure 3.2 illustrates how the priority of a project depends on which metric is used. According to the site energy use line (red), heating, which is mainly by natural gas, uses more energy per square foot than lighting, which is all electric. But the primary energy use line (blue) shows that it is lighting which is the most energy intensive. Systems-based thinking would prioritize attention to electric lighting to reduce costs and greenhouse gas emissions. Systems-based thinking can also be applied to water use. In conventional thinking, potable water, which is chemically processed at treatment plants and transported to building sites, is used not only for drinking but also for building equipment and fixtures and to irrigate landscaping. A systems-based approach, in contrast, considers using rain- and stormwater for purposes other than drinking. In a sys- tems-based approach, the goal is to use potable water at least twice (first for drinking, then for filtered 70 Primary Use Energy 200 60 50 150 Thousand Btu/ft2 40 kWh/m2 100 30 20 50 Site Use Energy 10 0 0 Lighting Electronics Computers Cooking Refrigeration Other Heating Cooling Ventilation Water Heating FIGURE 3.2 U.S. commercial buildings’ energy consumption by end use in 2006. NOTE: For end uses that are entirely electric the blue point (consumption of primary energy) is simply three times higher than the red point. For uses like cooking with natural gas, the points coincide. For mixed gas/electric ig 3-2.eps approach one another. SOURCE: DOE, 2008. f uses the points bitmap
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30 ACHIEVING HIGH-PERFORMANCE FEDERAL FACILITIES grey water uses1). Filtered grey water can be used in building equipment and for landscape irrigation. In this way, a systems-based approach can reduce the demand for potable water and, in turn, reduce the energy costs and the cost of chemicals involved in processing and transporting potable water to a site. Managing all stormwater on site can reduce flooding due to stormwater runoff from building sites. Less flooding, in turn, contributes to reducing combined storm-sewer overflow. Systems-based thinking can be applied to many other processes, including waste management and transportation, and it can be applied at many levels, from global and regional to communities, buildings, and supply chains. A corollary to systems-based thinking for innovation in the built environment is life-cycle account- ing. Agencies could pursue three levels of life-cycle accounting to help meet their mandates related to high-performance buildings: • Traditional life-cycle costing with operational costs factored into first-cost trade-offs; • Life-cycle assessment that evaluates a full range of environmental consequences from global warming and ozone depletion to habitat reduction and human health; and • Triple bottom line accounting in which net present value calculations are completed three times, weighing hard economic benefits for the owner first, softer environmental benefits for society second, and known human benefits such as health, productivity, and even jobs last of all. PORTFOLIO-BASED FACILITIES MANAGEMENT Just as the scope and scale of building design are evolving, so is the focus of facilities management. Much of this change has occurred in parallel with the growth of information technology and with the increased expectations of facility owners and users for building performance and cost effectiveness (NRC, 2008). In the last 20 years, public and private organizations with large inventories of facilities have shifted from managing individual buildings to managing entire portfolios of facilities (Figure 3.3). The shift to portfolio-based management has been driven, in part, by the recognition of the costs of facilities, the role of facilities in organizational operations, and the impacts of facilities on workforce health and safety. This recognition has led to a more strategic approach that views facilities as assets that enable the production and delivery of goods and services. Portfolio-based facilities management has been defined as a Systematic process of maintaining, upgrading, and operating physical assets cost effectively. It combines engineer- ing principles with sound business practices and economic theory, and provides tools to facilitate a more organized, logical approach to decision making. A facilities asset management approach allows for both program or network- level management and project-level management and thereby supports both executive-level and field-level decision making. (NRC, 2004, p. 32) Effective portfolio-based facilities management looks holistically at the entire inventory of existing buildings and considers new investments within this context. Life-cycle costing is used for all potential investments. Portfolio-based facilities management can be used to align facilities with missions, to identify excess facilities and underutilized space, to limit the construction of new space, and to identify opportunities for consolidating space. Well-designed facilities portfolio management programs start with a clear framing of facilities- management goals linked to overarching organizational goals and missions. The goals are used as a 1 Grey water is wastewater from hand washing, showers, and kitchen appliances such as dishwashers and washing machines. It does not include water from toilets.
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31 LEVERS OF CHANGE FIGURE 3.3 Evolution of facilities management functions. SOURCE: NRC, 2008. fig 3-3.eps bitmap basis for decision making through all aspects of facilities management, from planning and programming, design and construction, operations, maintenance and repair, retrofit, and demolition. During planning and programming for a new activity, an agency using a portfolio-based approach first determines if the new activity or program can be accommodated within the existing portfolio of buildings or if the activity can be provided through alternative noncapital solutions such as operations scheduling or leasing, or by using Web-based technologies. By not constructing a new building, agencies can realize multiple benefits including the avoidance of a building’s life-cycle costs, and environmental impacts. When new facilities are needed, the choice of location and site for the facility will have implica- tions for the ultimate sustainability of the building and its total life-cycle costs. For example, the local climate will determine the types and amounts of natural resources that can be drawn upon for the build- ing design (e.g., amount of sunshine, local temperatures), and locations near public transportation may reduce the space needed for on-site parking. The size of the site will also help determine how effectively natural resources, such as daylight, wind, and water, can be used to reduce energy and water use in one or more buildings. The importance of site selection for building new high-performance facilities is recognized in the Energy Independence and Security Act of 2007, the “Guiding Principles for Federal Leadership in High Performance and Sustainable Buildings,” and in Executive Order 13514. In April 2010, “Recommenda- tions on Sustainable Siting for Federal Facilities” was published. The document was a collaborative effort of the U.S. Departments of Transportation, Housing and Urban Development, Defense, and Homeland Security, the General Services Administration (GSA), and the Environmental Protection Agency. It is
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32 ACHIEVING HIGH-PERFORMANCE FEDERAL FACILITIES FIGURE 3.4 Recommended framework for effective federal facilities asset management. SOURCE: NRC, 2008. fig 3-4.eps bitmap intended to fulfill Section 10 in Executive Order 13514 which calls for providing the chair of the Council on Environmental Quality with recommendations for sustainable location strategies for consideration in federal agency sustainability plans.2 An NRC report (2008) found that to fully implement a facilities portfolio asset management approach, federal agencies require a workforce with a set of core competencies in three areas of expertise and with a skills base. The three areas of expertise are • Integrating people, processes, places, and technologies by using a life-cycle approach; • Aligning the facilities portfolio with the organization’s missions and available resources; and • Innovating across traditional functional lines and processes to address changing requirements and opportunities. The skills base includes a balance of technical, business, and behavioral capabilities along with enterprise knowledge. Enterprise knowledge includes an understanding of the facilities portfolio and how to align it with the organization’s mission; of the organization’s culture, policy framework and financial constraints; of agency inter- and intra-dependencies; and of the workforce’s capabilities and skills (NRC, 2008) (Figure 3.4). The Federal Buildings Personnel Training Act of 2010 (Public Law 111-308) 3 directs the GSA, in consultation with others, to identify the core competencies necessary for federal personnel performing building operations and maintenance, energy management, safety, and design functions. The competen- cies include those related to building operations and maintenance, energy management, sustainability, water efficiency, safety (including electrical safety) and building performance measures. The Act also 2 The document is available at http://www.dot.gov/livability/docs/siting_recs.pdf. 3 The full text of the law is available at http://www.gpo.gov/fdsys/pkg/PLAW-111publ308/pdf/PLAW-111publ308.pdf.
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33 LEVERS OF CHANGE specifies that not later than 18 months after the date of enactment, and annually thereafter, the GSA in conjunction with the Department of Energy, and in consultation with others, shall develop a recom- mended curriculum for facility management and the operation of high-performance buildings. INTEGRATED WORK PROCESSES Integrated work processes are essential for achieving the multiple objectives associated with high- performance buildings. They can be used to overcome the failure to optimize resources inherent in con- ventional, segmented processes; to support a life-cycle perspective; and to overcome time lags created by the budget process. A recent report of the National Academies found that The main difference between high-performing buildings and conventional buildings is essentially an attention to integration, interaction, and quality control throughout the design, construction, and operation of a building. This process, typically referred to as integrated design, represents a transformation not in technology but in conceptual thinking about how building systems can most effectively work together and the successful implementation of design intent. (NAS, 2010, p. 96) The value of integrated processes has been widely recognized. For example, the “Guiding Principles for Federal Leadership in High Performance and Sustainable Buildings” directs federal agencies to use a collaborative, integrated planning and design process that • Initiates and maintains an integrated project team in all stages of a project’s planning and delivery; • Establishes performance goals for siting, energy, water, materials, and indoor environmental quality along with other comprehensive design goals; • Ensures incorporation of these goals throughout the design and life cycle of the building; and • Considers all stages of the building’s life cycle, including deconstruction. The American Institute of Architects (AIA) defines integrated project delivery as a project delivery approach that integrates people, systems, business structures, and practices into a process that col- laboratively harnesses the talents and insights of all participants to reduce waste and optimize efficiency through all phases of design, fabrication, and construction. (AIA, 2007, p. 1) The International Council for Research and Innovation in Building and Construction (CIB) 4 recently launched the theme “Improving construction and use through integrated design solutions.” The CIB stated that Integrated design solutions use collaborative work processes and enhanced skills, with integrated data, information, and knowledge management to minimize structural and process inefficiencies and to enhance the value delivered during design, build, and operation, and across projects. (CIB, 2009, p. 1) 5 Collaboration is a common theme through all of the above definitions. To be effective, an integrated design process uses a design team having diverse expertise and perspectives: the owner’s representa- tives, contractors, architects, engineers, land use planners, interior designers, facilities managers, pres- ervationists, procurement, finance, and security specialists, among others. Such a team must be able 4 More information available at http://www.cibworld.nl/site/home/index.html. 5 Available at http://heyblom.websites.xs4all.nl/website/newsletter/0907/ids2009.pdf.
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34 ACHIEVING HIGH-PERFORMANCE FEDERAL FACILITIES to work collaboratively to achieve a given set of crosscutting and interrelated objectives. In addition, they must understand the interactions of building systems and technologies, which technologies will have immediate paybacks and which will have longer range paybacks in order to make trade-offs and well-informed decisions. Integrated design processes can be used with any project delivery method (e.g., design-build, design-bid-build). Such efforts require more up-front planning and time commitment than conventional processes. However, the benefits can be immediate and long-lasting. A study published by the National Science and Technology Council (NSTC) found that There is a limit to the overall energy savings potential of mainstream approaches for reducing energy use in new buildings. Major national studies agree that this limit ranges from 30% to 50% . . . . Integrating technologies with the building design (form) to create a building that delivers efficiency as a single system, however, can raise savings to 70% of building energy use compared with conventional new design. (NSTC, 2008, p. 17) PROCUREMENT, CONTRACTING, AND FINANCE Federal agencies spend billions of dollars annually to procure furnishings, equipment, computers, and other facility-related products. They also spend billions of dollars to lease physical space and to contract with private-sector firms for design, construction, operations, and maintenance services. The use of procurement and contracting methods as a lever of change is recognized in Executive Order 13514, which specifically directs agencies to leverage their acquisitions to foster markets for sustainable products and to ensure that new contract actions advance energy-efficient, water-efficient, and environmentally preferable products. Specifying Energy Star appliances and equipment, WaterSense fixtures,6 and FEMP-designated electronics in contracts and task orders would result in improved energy and water performance almost automatically. The Executive Order also ties the leasing of physical space to achievement of the Guiding Principles. COMMUNICATION AND FEEDBACK FOR BEHAVIORAL CHANGE Implementing systems-based thinking, portfolio-based facilities management, and integrated work processes requires changes in mindset throughout federal agencies. Change within an organization requires leadership and effective communication so that all members of the organization understand and accept that the goals and objectives are the right ones to pursue. Because a facility’s overall performance is, in part, a function of how the occupants use it, occupants need to understand how proper operation of facility systems (e.g., HVAC systems and controls) can affect their health and productivity, and how they can help achieve the goals for high-performance facilities. If sustainable practices are to become embedded in decision making at all levels of government, facilities managers and other federal staff will need to be more effective in communicating how high-performance facilities enable the agency’s mission. Best-practice organizations have long used performance measurement as a basis for good communi- cation, for changing conventional processes, and for changing human behavior. Performance measures help to identify where objectives are not being met or where they are being exceeded. Managers can then investigate the factors or reasons underlying the performance and make appropriate adjustments. Continuous process monitoring and feedback is also necessary because however effectively one plans, unintended consequences, unforeseen events, and change will occur (NRC, 2004). 6 Additional information available at http://www.epa.gov/WaterSense/.
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35 LEVERS OF CHANGE STANDARDS AND GUIDELINES Federal agencies can embed sustainability into day-to-day decision making through the use of standards and guidelines. For example, many federal agencies maintain their own sets of design and operations standards to address the types of facilities that they typically manage or contract for. Over time, the standards are updated to embed lessons learned from the design and operation of buildings in order to replicate successes and eliminate failures. Because of the relative newness of some sustainable design and operations practices, existing standards may not be supportive of some aspects of high- performance facilities and associated technologies. One relatively easy way to make sustainability the preferred choice is to review existing standards and revise them as necessary to ensure they support the development of high-performance facilities. More than 10 rating systems for green buildings that offer certifications for building performance have been developed worldwide (IFMA Foundation, 2010). Three systems available for buildings out- side their home countries are the Building Research Establishment Environmental Assessment Method (BREEAM, www.breeam.org), Leadership in Environmental and Energy Design (LEED, www.usgbc. org), and Green Globes (www.greenglobes.com) (IFMA Foundation, 2010). A number of federal agencies are using the LEED or Green Globes guidelines. Some have estab- lished policies that require new buildings or major retrofits to achieve a particular level of LEED—for example, Certified, Silver, Gold, or Platinum. Some require third-party certification of the design, while others self-certify.7 Two new standards are available for use by federal agencies. The American National Standards Institute and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers have issued Standard 189.1-2009, Standard for the Design of High-Performance Green Buildings, which specifies minimum requirements for the siting, design, construction, and planning for operation of high- performance green buildings.8 The International Organization for Standardization has issued Standard 15392, Sustainability in Construction—General Principles.9 It establishes internationally recognized principles for sustainability in building construction and establishes a common basis for communica- tion of the information required among policy makers, regulators, manufacturers, building owners, and consumers. This standard may be especially useful to agencies with facilities outside the continental United States. TECHNOLOGIES AND TOOLS Many new technologies are available for use in new high-performance facilities and for retrofits of existing buildings. These technologies can be used to reduce greenhouse gas emissions; reduce the use of energy, water, fossil fuels, potable water, and toxic and hazardous materials; improve stormwater management; increase the use of renewable sources of energy; and take advantage of natural resources, including daylight, solar power, and geothermal. The challenge of identifying the full range of high-performance systems and components that should be pursued for energy and environmental effectiveness is beyond the scope of this report. Key technolo- gies for resource efficiency have been identified in reports such as Real Prospects for Energy Efficiency in the United States (NAS-NAE-NRC, 2010), Greening Federal Facilities: An Energy, Environmental, and Economic Resource Guide for Federal Facility Managers and Designers (DOE, 2001), and Federal 7 Additional information is available at http://www.usgbc.org/DisplayPage.aspx?CMSPageID=1852#federal. 8 Copies are available for purchase at http://www.techstreet.com/cgi-bin/detail?doc_no=ASHRAE|189_1_2009&product_id=1668986. 9 Copies are available for purchase at www.iso.org.
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36 ACHIEVING HIGH-PERFORMANCE FEDERAL FACILITIES Research and Development Agenda for Net-Zero Energy, High-Performance Green Buildings (NSTC, 2008), among others. Examples of some of the technologies that should be of interest to federal agencies are the following: • High-efficiency electrical lighting systems that incorporate state-of-the-art lamps, ballasts, and lighting fixtures; lighting fixtures that provide the desired lighting in the right places (e.g., task lighting); and controls that limit electrical lighting when daylighting is available and minimize heat loss. • Fenestration (windows and doors) systems and designs that reduce heat gain in climates with high cooling requirements, while enabling daylight and views as well as passive solar heating when needed; low-E window glass to reduce heat loss. • “Cool” roofs, including white roofs that offset the heating effect of carbon dioxide per unit area by reflecting incident sunlight and green (vegetated) roofs that retain rainwater and cool the building below. • Solar technologies that can be incorporated into building roofs and facades for on-site power generation and water heating. • HVAC controls that provide for the effective operation of the system during partial load conditions; split ventilation systems and thermal systems. • Energy Star rated appliances and equipment that are more energy efficient than conventional appliances; WaterSense fixtures that are more water efficient than conventional fixtures; FEMP- designated electronic products that are more sustainable than conventional electronics; voice- over-Internet to replace standard telephones. • Meters, sensors, and “dashboards” that provide real-time information on water and energy use. • Porous pavers, cisterns, and low-flow irrigation systems to reduce the use of potable water and improve stormwater management; grey water systems that can recycle potable water, rainwater and stormwater for use in building equipment and for the landscape. Where facilities occupy large, contiguous land areas, federal agencies have opportunities to install combined heat and power (co-generation) plants that can use a variety of renewable sources of energy (solar, wind, biomass, solid waste); arrays of solar panels and wind turbines; district energy systems and other technologies. Most, if not all, of these technologies are most effective when used in combination with other tech- nologies and when enabled by systems-based thinking, portfolio-based facilities management, integrated work processes, and other levers of change, as discussed below. IDENTIFYING THE LEVERS OF CHANGE THAT ENABLE SPECIFIC TECHNOLOGIES AND SYSTEMS Implementing the technological upgrades and advances that are needed in federal buildings to achieve energy and environmental goals may require specific levers of change. For instance, district energy systems and on-site power generation are possible with systems-based thinking and portfolio- based facilities management. District energy systems provide centrally managed supply and delivery of heating, cooling, and domestic hot water to concentrations of buildings in close proximity. Steam, chilled water, and hot water can be produced from both fossil fuels and renewable energy sources or a combination. District energy systems are closed-loop systems that are able to reuse heat that would
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37 LEVERS OF CHANGE be wasted in conventional open-loop systems. As previously pointed out, more than 65 percent of the energy produced in electricity generation at the power plant is lost in the form of heat. District energy systems are widely used in Europe and Scandinavia and in some U.S. cities and on college campuses. Advanced systems use municipal solid waste, biofuels, and combined cycle solar and fuels for the combined generation of power and heat at the lowest energy cost. Systems-based thinking combined with portfolio-based facilities management can also enable the use of grey water technologies to achieve more efficient use of potable water, the use of rainwater capture systems, and technologies for stormwater management such as porous pavers. Integrated design processes are especially important in retrofitting buildings with new technologies because many technologies are interrelated and cross disciplinary boundaries. For example, energy use for lighting can be reduced by almost one-third by using T-8 lamps, electronic ballasts, occupancy controls, daylight dimming, and improved lighting design (NRC-NAE-NRC, 2010, p. 77). However, even greater savings are likely possible through integrated design of task ambient lighting with daylight through windows and skylights, task lights, and user controls of all three. Staff at the Lawrence Berkeley National Laboratory have calculated that average lighting energy use would be reduced from 1.69 to 0.45 watts per square foot of space through the introduction of an integrated office lighting system that combines lower levels of ambient overhead lighting with an efficient personal (task) lighting system (Brown et al., 2008). Additional energy savings can be achieved from the increased use of daylight for ambient and task lighting. Indeed, daylight “harvesting” has been shown to reduce total lighting energy loads in buildings by 5 to 50 percent depending on the depth of the building (Rubinstein and Enscoe, 2010). The ultimate energy benefits are dependent on the performance of the integrated system of high-efficiency ambient and task electric lighting, daylighting through existing windows with light redirection, shade and glare control, as well as fully engaging the building occupants in determining appropriate light levels and maximum energy savings. The design of an integrated system is dependent not only on the architect, lighting engineer, and interior designer but also on the manufacturers of lighting fixtures, ballasts, lamps, and controls. Integrated design processes are critical for meeting heating and cooling demands. A significant number of federal buildings are more than 40 years old (NRC, 1998), an age where perimeter heating systems and windows are failing and overall performance is declining, which increases the amount of energy used for heating, ventilation, and air conditioning. Perimeter heating and cooling demands are driven by climate and the performance of windows, so addressing these features together during building design and retrofit is important. Wall insulation and window technologies have advanced significantly in the past 10 years, and now have the potential to eliminate perimeter heating altogether, especially if internal heat gains can be used to offset perimeter losses through innovations such as advanced tech- nologies for windows, including air flow windows. Replacing existing windows, heating, cooling, and air-conditioning systems that have reached the end of their service lives with more efficient systems, including automated control systems, can help to create higher-performance federal facilities. Energy reductions of as much as 55 percent in existing buildings could be realized through improved HVAC equipment and controls (NAS-NAE-NRC, 2010). Portfolio-based facilities management can be a lever for improving the performance of roofs on federal buildings. Technologies for cool roofs, both white and green (vegetated) roofs (Figure 3.5), can contribute to reduced heating and cooling loads. In locations with summer cooling loads, both white and green roofs are equally effective at reducing the heat load on the building space below the roof. White roofs are almost three times as effective as green roofs when it comes to offsetting the heating effect of
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38 ACHIEVING HIGH-PERFORMANCE FEDERAL FACILITIES fig 3-5.eps FIGURE 3.5 White roof installed on the headquarters building of the Department of Energy; green roof installed on Chicago’s city hall. bitmap CO2 (carbon dioxide) per unit area of roof, because of their greater solar reflectance. A notable advantage of green roofs, however, is that they retain up to 75 percent of incident rainwater, which subsequently evaporates, cooling the roof itself and the building below. Although well-insulated white roofs can be ensured through performance-based procurement pro- cesses, systems-based thinking, combined with integrated work processes, can be used to develop cool, white roofs that also capture 100 percent of their rainwater to store and use on site, so they provide many of the advantages of green roofs. Rainwater capture for both types of roof typically involves installing a cistern at ground level and using the rainwater for irrigation or for equipment such as cooling towers. The commitment to on-site rainwater capture reduces the use of potable water for nonpotable uses, which can result in measurable energy savings and reductions in the use of hazardous chemicals for water treatment and transport. These examples are intended to illustrate the importance of identifying the lever or set of levers most critical to enabling each technology or integrated design solution to rapidly advance the energy and environmental performance of federal buildings. Examples of best practices that showcase the effective use of these technologies and others, as well as the other levers of change, are the focus of Chapter 4.