CS-2009 EAc1: Optimize Energy Performance

  • CS-2009 EA Optimize Energy Performance- Credit Requirements
  • A lot is at stake here

    EAc1: Optimize Energy Performance is, by farFloor-area ratio is the density of nonresidential land use, exclusive of parking, measured as the total nonresidential building floor area divided by the total buildable land area available for nonresidential structures. For example, on a site with 10,000 square feet (930 square meters) of buildable land area, an FAR of 1.0 would be 10,000 square feet (930 square meters) of building floor area. On the same site, an FAR of 1.5 would be 15,000 square feet (1395 square meters), an FAR of 2.0 would be 20,000 square feet (1860 square meters), and an FAR of 0.5 would be 5,000 square feet (465 square meters)., the most important credit in LEED, based on the number of points available. Up to 21 points are at stake here based on how much you’re able to reduce the project’s predicted energy cost. That large amount of points also reflects the great importance LEED places on reducing energy use and forestalling climate change1. Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). (U.S. Environmental Protection Agency, 2008) 2.The increase in global average temperatures being caused by a buildup of CO2 and other greenhouse gases in the atmosphere. This temperature change is leading to changes in circulation patterns in the air and in the oceans, which are affecting climates differently in different places. Among the predicted effects are a significant cooling in Western Europe due to changes in the jet stream, and rising sea levels due to the melting of polar ice and glaciers..

    You have some options to choose from. For certain buildings types you can opt to skip the energy modeling option and simply follow a list of prescriptive requirements, but you can’t earn nearly as many points that way, and you won’t have the benefit of the energy simulation to guide you to the most cost-effective energy efficiency measures.

    This credit is documented in concert with EAp2: Minimum Energy Performance. Refer to EAp2 for detailed steps on LEED compliance and documentation.

    Energy efficiency pays 

    An energy-efficient building can cost more to build, through components like efficient mechanical equipment and high-performance glazing. On the other hand, those same higher-cost measures can generate savings by reducing the size of mechanical systems. And of course, dramatic financial savings can come during the operational phase. Energy modeling can help determine the “sweet spot” for your project.

    Your project may also qualify for financial incentives offered by utilities or local, state, and federal authorities, that help offset the premiums of system upgrades and renewable energy implementation. In many states, utilities or other local entities provide financial incentives in the form of rebates or tax breaks to alleviate the cost premiums associated with installing systems and purchasing equipment geared toward energy efficiency. (See Resources for incentives.)  

    Three options, but only one gets you many points

    Documentation for this credit happens along with documentation for the associated prerequisite, EAp2: Minimum Energy Performance. In fact, for the prescriptive options, all you have to do is document the prerequisite—no further information is required to earn a point under the credit. 

    Three compliance options are available.

    • Option 1 offers the potential to earn the maximum number of points available for this credit, for improved energy efficiency. This requires whole building energy simulation using a computer model. Your project must reduce energy cost by a minimum of 10% (5% for an existing building) to meet the prerequisite, EAp2. Under EAc1 you can earn one point for each additional 2% of energy cost reduction from the referenced standard (see the table in the credit language for exact amounts). The energy modeling and documentation process is identical for EAp2 and EAc1, Option 1. The exact reduction is established when you run your energy model. 
    • If your project pursues the prescriptive compliance paths of Options 2 and 3, you automatically earn one point under EAc1 simply by documenting your prerequisite compliance. 
    • Option 3: Compliance with the prescriptive measures of the Core Performance Guide (CPG) offers an opportunity for a maximum of 3 points. One point is earned for compliance with the CPG. An additional one or two points are available for meeting any three or six requirements, respectively, of Section 3 of the CPG. These requirements range from installing a renewable energy system to adding filters to air-handling systems. Review these requirements with your team to select the three or six that are most applicable to your project.

    Design and technology choices

    With clearly defined goals and committed team members, your project should be able to achieve an energy cost reduction of 10% to 15%, through measures such as the following.

    • Making conscious design decisions to reduce energy loads 
    • Minimizing glazing areas on the east and west exposures
    • Passive solar design 
    • Energy-efficient glazing 
    • Reducing the lighting power density 
    • Demand-controlled ventilation 
    • Efficient mechanical equipment 
    • Occupant sensor lighting controls 
    • Energy Star appliances 
    • A modest onsite renewable energy system. 

    If you want to aim for higher targets of 20%–50% energy savings or higher, consider measures such as the following.

    • Natural ventilation
    • Daylight harvesting with automatic dimmers/switching on electric lighting
    • Reducing heating and cooling loads through improved glazing, insulation, and exterior shading devices 
    • Energy recovery ventilation
    • A larger onsite renewable energy system. 

    The most cost-effective measures vary by building type and location—refer to ASHRAE Advanced Energy Design Guides and case studies for appropriate strategies in your building. (See Resources.) 

    Integrated design 

    Building energy performance is a result of interactions between various different building components and systems. The mechanical system consumes energy based on factors such as architectural design, operating schedules, programming and climate. To significantly reduce energy it is very important for all team members to share design ideas and collaborate on strategies. The integrated design process will support constant communication, fast response on new ideas, and  can help eliminate misunderstandings or assumptions—consider using it as a central strategy to earning points for this credit. 

    Special considerations for district energy

    If your project is connected to a district energy systemA central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity., LEED 2009 lets you take advantage of improved system efficiencies. Although not permitted for use with EAp2, you may include the improved efficiency over baseline of the district energy system in the energy model you develop for EAc1. In this scenario, you develop a separate model from the one for EAp2 compliance. (See Resources for more details through the updated guidelines.)

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Pre-Design

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  • This credit is documented in concert with EAp2: Minimum Energy Performance. Refer to EAp2 for detailed steps on LEED compliance and documentation. 


  • Begin identifying a target for energy performance. Begin by researching similar building types using the EPA Target Finder program. An Energy Star score of 80 or higher will typically earn EAc1 points. 


  • To earn points for EAc1 you’ll most likely have to significantly exceed your local energy code. Achieving this energy reduction requires special attention to detail by your entire team from the beginning of the design process, and dedicated leadership from the owner.


  • Note that energy efficiency is not just about efficient boilers and chillers. To achieve high targets, the design of the building has to help reduce dependence on mechanical heating and cooling throughout the year, through measures like orientation, moderate glazing areas, and self-shading. 


  • An automated building management system (BMS) can significantly reduce building energy use by turning down air conditioning and turning off lights during unoccupied hours, along with other similar measures. Occupancy sensors, timers, and temperature sensors feed into the system to switch off lights and fans when not needed. Note that controls can be counted towards energy reductions only through energy modeling.


  • Choosing your compliance path


  • The compliance paths for this credit are the same as for EAp2. Because the documentation is identical, it makes the most sense to consider credit implications when selecting the appropriate compliance path for the prerequisite. 


  • Complying with Option 2 earns only one point, and with Option 3, 1-3 three points. If you are committed to greatly reducing energy usage and earning a higher number of points, then follow Option 1 for both EAp2 and EAc1.


  • Renewable energy shows the contrast between Options 1 and 3. Installing a renewable energy system for 5% of electricity use earns one-third of a point through Option 3. Installing a renewable energy system to reduce building energy costs by 2% earns one point under Option 1.


  • You can earn up to 19 points through EAc1, Option 1, using the same methodology as for EAp2, Option 1.


  • Only one point is available through Option 2: Prescriptive Compliance Path: ASHRAE Advanced Energy Design Guide, but if you choose this path for EAp2, it is earned automatically and does not carry any additional requirements. This option is available to office or retail projects up to 20,000 ft2 or warehouses less than 50,000 ft2. If you choose this compliance path, become familiar with the list of prescriptive requirements, and commit to meeting them. (See the AEDG checklist in the Documentation Toolkit.)


  • Up to three LEED points are available under Option 3 for compliance with the Core Performance Guide. It’s a good option if your project is smaller than 100,000 ft2, does not fall into one of the Option 2 categories and you’d rather not commit to energy modeling (Option 1). Your project automatically earns one point for meeting the prerequisite. An additional one or two points are available for meeting any three or six requirements, respectively, of Section 3. These requirements range from installing a renewable energy system to adding filters to air-handling systems. Review these requirements with your team to select the three or six that are most applicable to your project.


  • Some energy conservation measures, such as energy recovery ventilation or a highly insulated building envelope, add to both construction and design costs, though with an integrated design process these costs might be recouped through savings elsewhere, such as through reducing the size of the mechanical system. The most effective approach is to have your building owner and design team together evaluate both the first costs of the energy-saving measures and their effectiveness at reducing operating costs. 


  • If you are connected to a district energy system, you are better off pursuing Option 1, because only through energy modeling can you benefit from the efficiencies of the district energy system. 


  • Option 1: Computer Simulation


  • The model you need to develop for EAc1 is the same as for EAp2 (unless you’re on a district energy system). 


  • Follow the guidelines on identifying energy-efficiency strategies to achieve the owner’s energy efficiency goals per the Owner’s Project Requirements, developed for EAp1: Fundamental Commissioning.


  • Your mechanical engineer and energy modeler need to work in collaboration with the architect when finalizing building form, façade treatment, and programming—to give real-time input on the energy impact of all the design features. 


  • Consider highly efficient systems like heat pumps for heating and cooling, district energy and cogeneration, ice storage for off-peak cooling, or energy recovery ventilation—to attain a substantial energy reduction of 10%-20%. 


  • If your building includes the use of purchased steam supplied to your HVAC system, the proposed (design) building is modeled as if the steam system is “located” in the building— with the same efficiency with which it typically operates. The designed building is allocated only the fuel cost (for natural gas or oil) required to generate and deliver the steam needed for the building.  The steam purchased is actually considered “free,” as steam rates are not included. And here is where your building really benefits—if the steam system also co-generates electricity along with steam, that electricity is assumed to be “free” to the proposed building, as well. (Refer to the latest guidelines from USGBC.)  


  • Energy-efficient design can increase your construction budget. Use your computer model to optimize packages of upgrades that balance any added costs against cost savings, and run payback analyses to identify the most cost-effective options.  


  • Even if you’re using Option 1, refer to the Advanced Energy Design Guides and Core Performance Guide (referenced by Options 2 and 3) for ideas on cost-effective measures to implement.


  • Option 2: Prescriptive Compliance Path—ASHRAE Advanced Energy Design Guides 


  • If you complete the documentation for EAp2, Option 2, you automatically earn a point through EAc1. The requirements are identical to EAp2 and require minimum additional time on the part of your engineer.  


  • If you meet the prerequisite through Option 2, and document it, you earn a point through the credit—it’s that simple.


  • Option 3: Prescriptive Complance Path—Advanced Buildings Core Performance Guide 


  • If you complete the documentation for EAp2, Option 3, you earn one point through EAc1, Option 3.  The requirements are identical with EAp2 and requires minimal additional time on the part of your engineer.  


  • Review Section 3 of the Core Performance Guide to identify three or six of the 11 available strategies (for one or two points, respectively) to pursue.


  • If you are installing a renewable energy system that provides at least 5% of your electricity, you already implemented one of the three strategies from the Core Performance Guide. 


  • If you meet the prerequisite, and document it, you achieve one point —it’s that simple.


  • Note that the credit language excludes three of the strategies of the Core Performance Guide from helping you earn the credit. This is because these areas are covered thoroughly by other LEED credits. 

    • 3.1: Cool Roofs,
    • 3.8: Night Venting,
    • 3.13: Additional Commissioning. 

  • Select those strategies that are most suitable for your project type and location. For example, evaporative cooling is very effective in a hot, dry climate but is not likely to be a good idea in the cooler, damper Northeast or Northwest. The list is a good summary of the best ways to reduce energy intensity, though some strategies may be more effective in offices and museums, while others are more helpful in hospitals and hotels. 

Schematic Design

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  • Develop multiple iterations of your project design to analyze the energy impact of each change. 


  • Option 1: Computer Simulation


  • Further develop energy optimization strategies with the design team. Look at reducing loads while creating a comfortable environment within the shell. Look at reducing east and west exposures, and at providing south windows with exterior shades to make a design feature out of passive techniques. Discuss highly efficient system design at this stage, before your design is finalized—for example: 

    • double wall systems 
    • ground-source heat pumps 
    • underfloor air distribution. 

  • Ecotect and IES Virtual Environments, among other software tools, allow very quick analysis of alternative building forms and mechanical systems, allowing you to test alternative ideas, and develop a single idea in an iterative design process. (See Resources.)


  • Google SketchUp is good for shading studies, and plug-ins are available for IES and EnergyPlus to support energy analysis of Google SketchUp models.


  • Ventilation is one of the largest energy end-uses. Look at alternative means of ventilating your building. Consider naturally ventilated spaces, mixed-mode ventilation for moderate climates, and demand-controlled ventilation for mechanically ventilated spaces.


  • Daylighting makes for welcoming spaces, and can save energy both through reduced electric lighting and reduced cooling load due to the reduced electric lighting. Consider an atrium and skylights to serve ventilation and light functions. Integrate spatial programming within the atrium to utilize the space. See LEEDuser’s daylighting strategy for more.


  • Consider other techniques to upgrade the building envelope and insulation, such as: 

    • High performance glazing
    • Spray-foam insulation
    • Additional roof insulation
    • Highly-reflective roofing application
    • green roofs  
    • exterior shading devices.

  • By this stage, the architect should have seen a visual presentation by the energy modeler on multiple building forms with energy-use comparisons. This will help hone in on the most energy-efficient design that also supports the building program.


  • Option 2: Prescriptive—ASHRAE Advanced Energy Design Guides 


  • Follow EAp2 steps for compliance and documentation.


  • Option 3: Prescriptive—Advanced Buildings Core Performance Guide


  • If you are pursuing an additional point or two by complying with Section 3, select the strategies you anticipate pursuing. 


  • Some easily implemented strategies include: 

    • daylighting and controls, especially if you are pursuing IEQc6.1: Controllability of Systems—Lighting;
    • installing Energy Star appliances;
    • energy recovery ventilation, which is especially useful in moderate to harsher climates; 
    • and variable speed controls on pumps and fans.

Design Development

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  • Option 1: Whole Building Energy Simulation


  • One complete run of your energy model should be completed during design development to make sure the design is reducing annual energy cost by your targeted amount. This is the time when simplified models used to inform early design decisions should be replaced by a more comprehensive detailed model. Run two or three alternatives to help the designers finalize envelope and system selection. Common measures to consider include high-performance windows, additional roof insulation, and more efficient boilers. 


  • Use your energy model to review envelope thermal and hygrothermal performance. In a heating climate, thick insulation inside the air barrier may cause condensation problems. Consider an exterior thermal barrier to protect the air barrier and to prevent condensation inside the wall cavity. Identify thermal bridges in the walls and windows that could leak heat from inside. Add thermal breaks, such as neoprene gaskets, on shelf angles, silicone beading on window frames, and use other techniques to prevent leakage from the envelope. 


  • Your energy model can be a supportive design tool that provides insight into the actual performance of the building envelope and mechanical systems. It can highlight surprising results, such as a prominent feature like an efficient boiler contributing only a 1% reduction in energy cost. It can also provide evidence to support operational energy-use decisions such as changing the heating or cooling set points a few degrees. 


  • Option 2: Prescriptive—ASHRAE Advanced Energy Design Guides (AEDG)


  • Follow EAp2 steps for compliance and documentation.


  • Option 3: Prescriptive—Advanced Building Core Performance Guide


  • Make sure the identified measures are being implemented. For Section 3 items, check with the mechanical engineer on the status of each measure. Document the measures if they are completed, like daylight control locations and quantities and economizer performance. 


  • The baseline exterior lighting power allowance (ELPA) may not take credit for any category which does not have any lighting fixtures in the proposed building, or for any area or width within any category which is not lit in the proposed building, even within the tradable categories. In addition, the lighting for a single building component cannot be counted within two separate categories in the baseline ELPA calculations.

Construction Documents

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  • Finalize the design, including all energy system strategies. Make sure your project is on track for the target rating based on energy cost. 


  • Assess your compliance with the credit and projected points to be earned. This credit and option can be the largest contributor to your LEED point total, so if you aren’t hitting your goal, consider last minute design changes now. 


  • Specify and contract for efficiency measures. Often new equipment and novel systems are unknown to contractors, so hold bid and construction meetings to ensure your specifications are understood and everything is purchased and installed as intended. 


  • The more thorough your drawings and specifications are, the less the chances of incorrect installation. 


  • Contracting with a commissioning agent for the expanded scope of EAc3: Enhanced Commissioning is highly recommended. Any project relying on sophisticated controls and systems for energy efficiency needs the eye of an experienced commissioning agent during construction and functional testing. 


  • Energy systems are only as efficient as they are well-installed and operated—involve the operations team during the final Construction Documents phase (or even much earlier) to make sure they are abreast of design decisions and prepared to operate in the sequence required. 


  • Make sure mechanical spaces and locations are coordinated in the architectural and structural drawings. For example, is a duct run colliding with a beam? Is a fan coil unit placed above a door opening so that it will leak condensate on people walking into the space? Common mistakes like this can cause construction delays and poor performance during operations if not detected, so coordination of the drawings is critical, especially if your project involves integrated design and complex systems. 


  • Option 1: Whole Building Energy Simulation


  • When your final design is documented, run a final energy model for LEED documentation. Include the specifications and efficiencies of the system being purchased and installed.  


  • Option 2: Prescriptive Compliance Path—ASHRAE Advanced Energy Design Guides


  • Follow EAp2 steps for compliance and documentation.


  • Option 3: Prescriptive Compliance Path—Advanced Buildings Core Performance Guide


  • Follow EAp2 steps for compliance and documentation.


  • Finalize the list of strategies adopted from Section 3. Your project earns one point for three strategies, two points for six strategies. 

Construction

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  • All the design work is implemented during construction. Have the project architect ensure that the glazing is per your specifications and that the façade system incorporates a continuous air barrier. The commissioning agent will ensure all equipment purchased is exactly what the engineer required, and that all pumps and fans meet the specifications. 


  • If you are installing a BMS, configure and program it to specifications. If there was any change in system specifications, make sure it is accounted for in the BMS programming. 


  • If you are installing sensors and controls, they should be configured per specifications.  Surprisingly, these are occasionally mis-calibrated or even reversed, causing discomfort to occupants, cost to the owner, and system malfunction. 


  • Option 1: Computer Simulation


  • Although EAc1 is a Design Phase submittal, it may make sense to submit the credit after construction for LEED certification to take into account any final design changes.


  • Option 2: Prescriptive—ASHRAE Advanced Energy Design Guides (AEDG)


  • Make sure that the documentation from the prerequisite (EAp2) is complete in LEED Online. The documentation for EAc1 is, for the most part, automatically filled out in LEED Online based on your entries for EAp2.


  • Option 3: Prescriptive—Advanced Building Core Performance Guide


  • Install all equipment as required by the design specifications. 


  • If your team is installing features like VAV or a peak-load demand response system for the first time, check the installation and functional testing carefully. Get the vendor involved in writing the specifications to reduce risk of errors. 

Operations & Maintenance

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  • The first year of operations is usually a learning period for both the occupants and the facility manager. If your project underwent enhanced commissioning and developed an operations manual, you will have fewer miscommunications and untrained staff. Most medium and large projects install a BMS that centrally controls fans, pumps, part of the chiller and boiler load, and provides real-time energy-use data. Note that certain configurations require resetting, per feedback from users and the system itself. 

  • USGBC

    Excerpted from LEED 2009 for Core and Shell Development

    EA Credit 1: Optimize energy performance

    3–21 Points

    Intent

    To achieve increasing levels of energy performance beyond the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use.

    Requirements

    Select 1 of the 3 compliance path options described below. Project teams documenting achievement using any of the 3 options are assumed to be in compliance with EA Prerequisite 2: Minimum Energy Performance.

    Option 1. Whole building energy simulation (3-21 points)

    Demonstrate a percentage improvement in the proposed building performance rating compared with the baseline building performanceThe annual energy cost for a building design, used as a baseline for comparison with above-standard design. rating. Calculate the baseline building performance according to Appendix G of ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1) using a computer simulation model for the whole building project. Projects outside the U.S. may use a USGBC approved equivalent standard2. The minimum energy cost savings percentage for each point threshold is as follows:

    New Buildings Existing Building Renovations Points
    12% 8% 3
    14% 10% 4
    16% 12% 5
    18% 14% 6
    20% 16% 7
    22% 18% 8
    24% 20% 9
    26% 22% 10
    28% 24% 11
    30% 26% 12
    32% 28% 13
    34% 30% 14
    36% 32% 15
    38% 34% 16
    40% 36% 17
    42% 38% 18
    44% 40% 19
    46% 42% 20
    48% 44% 21



    Appendix G of Standard 90.1-2007 requires that the energy analysis done for the building performance rating method include all the energy costs associated with the building project. To achieve points under this credit, the proposed design must meet the following criteria:

    • Compliance with the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) in Standard 90.1-2007 (with errata but without addenda) or USGBC approved equivalent.
    • Inclusion of all the energy costs within and associated with the building project.
    • Comparison against a baseline building that complies with Appendix G of Standard 90.1-2007 (with errata but without addenda) or USGBC approved equivalent. The default process energy cost is 25% of the total energy cost for the baseline building. If the building’s process energy cost is less than 25% of the baseline building energy cost, the LEED submittal must include documentation substantiating that process energy inputs are appropriate.

    For the purpose of this analysis, process energy is considered to include, but is not limited to, office and general miscellaneous equipment, computers, elevators and escalators, kitchen cooking and refrigeration, laundry washing and drying, lighting exempt from the lighting power allowance (e.g., lighting integral to medical equipment) and other (e.g., waterfall pumps).

    Regulated (non-process) energy includes lighting (e.g., for the interior, parking garage, surface parking, façade, or building grounds, etc. except as noted above), heating, ventilating, and air conditioning (HVAC) (e.g., for space heating, space cooling, fans, pumps, toilet exhaust, parking garage ventilation, kitchen hood exhaust, etc.), and service water heating for domestic or space heating purposes.

    For this credit, process loads must be identical for both the baseline building performance rating and the proposed building performance rating. However, project teams may follow the exceptional calculation method (ANSI/ASHRAE/IESNA Standard 90.1-2007 G2.5) or USGBC approved equivalent to document measures that reduce process loads. Documentation of process load energy savings must include a list of the assumptions made for both the base and proposed design, and theoretical or empirical information supporting these assumptions.

    Projects in California may use Title 24-2005, Part 6 in place of ANSI/ASHRAE/IESNA Standard 90.1-2007 for Option 1.

    OR

    Option 2. Prescriptive compliance path: ASHRAE Advanced Energy Design Guide (1 point)

    Comply with the prescriptive measures of the ASHRAE Advanced Energy Design Guide appropriate to the project scope, outlined below. Project teams must comply with all applicable criteria as established in the Advanced Energy Design Guide for the climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. in which the building is located. Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.

    Path 1. ASHRAE Advanced Energy Design Guide for Small Office Buildings 2004

    The building must meet the following requirements:

    • Less than 20,000 square feet (1,800 square meters).
    • Office occupancy.
    Path 2. ASHRAE Advanced Energy Design Guide for Small Retail Buildings 2006

    The building must meet the following requirements:

    • Less than 20,000 square feet (1,800 square meters).
    • Retail occupancy.
    Path 3. ASHRAE Advanced Energy Design Guide for Small Warehouses and Self Storage Buildings 2008

    The building must meet the following requirements:

    • Less than 50,000 square feet (4,600 square meters).
    • Warehouse or self-storage occupancy.

    OR

    Option 3. Prescriptive compliance path: Advanced Buildings™ Core Performance™ Guide (1-3 points)

    Comply with the prescriptive measures identified in the Advanced Buildings™ Core Performance™ Guide developed by the New Buildings Institute. The building must meet the following requirements:

    • Less than 100,000 square feet (9,300 square meters).
    • Comply with Section 1: Design Process Strategies, and Section 2: Core Performance Requirements.
    • Health care, warehouse or laboratory projects are ineligible for this path (for NC & CS Projects).

    Points achieved under Option 3 (1 point):

    • 1 point is available for all projects (office, school, public assembly, and retail projects) less than 100,000 square feet (9,300 square meters) that comply with Sections 1 and 2 of the Core Performance Guide.
    • Up to 2 additional points are available to projects that implement performance strategies listed in Section 3: Enhanced Performance. For every 3 strategies implemented from this section, 1 point is available.
    • The following strategies are addressed by other aspects of LEED and are not eligible for additional points under EA Credit 1:
      • 3.1 — Cool Roofs
      • 3.8 — Night Venting
      • 3.13 — Additional CommissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements.

    Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.

    Pilot ACPs Available

    The following pilot alternative compliance path is available for this credit. See the pilot credit library for more information.

    EApc95: Alternative Energy Performance Metric ACP

    Potential Technologies & Strategies

    Design the building envelope and systems to maximize energy performance. Use a computer simulation model to assess the energy performance and identify the most cost-effective energy efficiency measures. Quantify energy performance compared with a baseline building.

    If local code has demonstrated quantitative and textual equivalence following, at a minimum, the U.S. Department of Energy (DOE) standard process for commercial energy code determination, the results of that analysis may be used to correlate local code performance with ANSI/ASHRAE/IESNA Standard 90.1-2007. Details on the DOE process for commercial energy code determination can be found at http://www.energycodes.gov/implement/determinations_com.stm.

    FOOTNOTES

    1 Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.

    2 Projects outside the U.S. may use an alternative standard to ANSI/ASHRAE/IESNA Standard 90.1‐2007 if it is approved by USGBC as an equivalent
    standard using the process located at www.usgbc.org/leedisglobal.

Organizations

Database of State Incentives for Renewables and Efficiency (DSIRE)

This database shows state-by-state incentives for energy efficiency, renewable energy, and other green building measures. Included in this database are incentives on demand control ventilation, ERVs, and HRVs.


American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

ASHRAE offers guidance for different levels of building energy audits.


American Council for an Energy-Efficient Economy

ACEEE is a nonprofit organization dedicated to advancing energy efficiency through technical and policy assessments; advising policymakers and program managers; collaborating with businesses, public interest groups, and other organizations; and providing education and outreach through conferences, workshops, and publications. 


American Society of Heating, Refrigerating and Air-Conditioning Engineers

 

ASHRAE has developed a number of publications on energy use in existing buildings, including Standard 100–1995, Energy Conservation in Existing Buildings. This standard defines methods for energy surveys, provides guidance for operation and maintenance, and describes building and equipment modifications that result in energy conservation. 2 publications referenced by this credit (ANSI/ASHRAE/IESNA 90.1–2007 and ASHRAE Advanced Energy Design Guide for Small Office Buildings 2004) are available through ASHRAE.

 


Energy Star

Energy Star is a joint program of U.S. EPA and the U.S. Department of Energy that promotes energy-efficient buildings, products, and practices. 


International Energy Agency Solar Heating and Cooling Programme

The Solar Heating and Cooling Programme was established in 1977, one of the first programmes of the International Energy Agency. The Programme's work is unique in that it is accomplished through the international collaborative effort of experts from Member countries and the European Commission.


New Buildings Institute

The New Buildings Institute is a nonprofit, public-benefits corporation dedicated to making buildings better for people and the environment. Its mission is to promote energy efficiency in buildings through technology research, guidelines, and codes.


U.S. Department of Energy, Building Energy Codes Program

The Building Energy Codes program provides comprehensive resources for states and code users, including news, compliance software, code comparisons, and the Status of State Energy Codes database. The database includes state energy contacts, code status, code history, DOE grants awarded, and construction data. The program is also updating the COMcheck-EZ compliance tool to include ANSI/ASHRAE/IESNA 90.1–2007. This compliance tool includes the prescriptive path and trade-off compliance methods. The software generates appropriate compliance forms as well. 


U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy

This extensive website for energy efficiency is linked to a number of DOE-funded sites that address buildings and energy. Of particular interest is the tools directory, which includes the Commercial Buildings Energy Consumption Tool for estimating end-use consumption in commercial buildings. The tool allows the user to define a set of buildings by principal activity, size, vintage, region, climate zone, and fuels (main heat, secondary heat, cooling and water heating) and to view the resulting energy consumption and expenditure estimates in tabular form. 


Architecture 2030

Non-profit organization aiming at design community to increase collaboration for designing energy efficient buildings.


IBPSA

International association of energy modelers with various national and local chapters. 


Low Impact Hydropower Institute

The Low Impact Hydropower Institute is a non-profit organization and certification body that establishes criteria against which to judge the environmental impacts of hydropower projects in the United States.


U.S. Department of Energy Building Technologies Program

The Building Technologies Program (BTP) provides resources for commercial and residential building components, energy modeling tools, building energy codes, and appliance standards including the Buildings Energy Data Book, High Performance Buildings Database and Software Tools Directory.

Web Tools

Advanced Buildings Technologies and Practices

This online resource, supported by Natural Resources Canada, presents energy-efficient technologies, strategies for commercial buildings, and pertinent case studies.


Computer simulation

This website provides details process to develop an energy model.


Lawrence Berkeley Lab: Building Technologies Department

Research warehouse for strategies and case studies of energy efficiency in buildings.


Efficient Windows Collaborative

An online window selection tool with performance characteristics.


CBECS

DOE website with database of energy performance of buildings across US.


Whole Building Design Guide (WBDG)

This website lays out design process for developing an energy efficient building.


AIA Sustainability Toolkit

This website is put together for architects with ideas on hundreds of ways to improve design for lower energy demand. 


Environmental and economic assessment tools available on internet

This document lists multiple web based or downloadable tools that can be used for energy analyses.


Database for energy efficient resource

This webtool is a database of strategies and vendors for energy efficient systems. 


Energy Design Resources - CA

Energy design tools are available to be used for free online or available to download.


Building Materials Property Table

This website lists performance characteristics for various envelope materials. 


One Building

This is an online forum of discussion for energy efficiency, computer model software users.


Building Energy Software Tools Directory

This directory provides information on 406 building software tools for evaluating energy efficiency, renewable energy, and sustainability in buildings.


EnergyPlus Format Weather Data Resources

Weather data for more than 2100 locations are available in EnergyPlus weather format.


DOE-2 Format Weather Data Resources

Weather data for U.S. and Non-U.S. locations in BIN format.


BEMbook – Building Energy Modeling Book

A web-based, free content project by IBPSA-USA to develop an online compendium of the domain of Building Energy Modeling (BEM). The intention is to delineate a cohesive body of knowledge for building energy modeling.

Publications

Energy Information Agency, Commercial Building Energy Consumption Survey

The Commercial Buildings Energy Consumption Survey (CBECSThe Commercial Buildings Energy Consumption Survey (CBECS) is a national sample survey that collects information on the stock of U.S. commercial buildings, their energy-related building characteristics, and their energy consumption and expenditures. Commercial buildings include all buildings in which at least half of the floorspace is used for a purpose that is not residential, industrial, or agricultural, so they include building types that might not traditionally be considered "commercial," such as schools, correctional institutions, and buildings used for religious worship. CBECS data is used in LEED energy credits.) is a national sample survey that collects information on the stock of U.S. commercial buildings, their energy-related building characteristics, and their energy consumption and expenditures. 


ANSI/ASHRAE/IESNA Standard 90.1–2007 User’s Manual (ASHRAE).

ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry.


Advanced Lighting Guidelines, 2003 edition (New Building Institute, Inc., 2003)

These guidelines are available as a free download or can be purchased as a printed manual of 390 pages. 


ANSI/IESNA RP-1-04, American National Standard Practice for Office Lighting (IESNA)

This Standard Practice provides useful, practical guidance on the technical issues where current research and consensus opinion have advanced, including information on design elements that can produce both a productive and pleasant work environment. 


Daylight in Buildings: A Source Book on Daylighting Systems and Components, Chapter 5, Daylight- Responsive Controls (Lawrence Berkeley National Laboratory)

This information is of particular benefit to building design practitioners, lighting engineers, product manufacturers, building owners, and property managers. Although the text emphasizes the performance of daylighting systems, it also includes a survey of architectural solutions, which addresses both conventional and innovative systems as well as their integration in building design.


Design Brief: Lighting Controls Energy Design Resources (Southern California Edison)

EDR offers a valuable palette of energy design tools and resources that help make it easier for architects, engineers, lighting designers, and developers to design and build energy-efficient commercial and industrial buildings in California. 


Electricity Used by Office Equipment and Network Equipment in the United States: Detailed Report and Appendices, by Kawamoto, et al. (Lawrence Berkeley National Laboratory, February 2001)

This ongoing project explores the effects of computers and other information technology on resource use.


Illuminating Engineering Society of North America Lighting Handbook, ninth edition (IESNA, 2000)

The Handbook provides up-to-date coverage of lighting development, evaluation and interpretation of technical and research findings, and their application guidelines.


Mechanical and Electrical Equipment for Buildings, ninth edition, by Benjamin Stein and John S. Reynolds (John Wiley & Sons, 2000)

The Ninth Edition provides students and professionals with the most complete coverage of the theory and practice of environmental control system design currently available. Encompassing mechanical and electrical systems for buildings of all sizes, it provides design guidelines and detailed design procedures for each topic covered. It also includes information on the latest technologies, new and emerging design trends, and relevant codes and zoning restrictions-and its more than 1,500 superb illustrations, tables, and high-quality photographs provide a quick reference for both students and busy professionals.


Sustainable Building Technical Manual (Public Technology Institute, 1996)

This manual covers nearly all disciplines involved in the design, construction and operation of green buildings.


Commercial windows

This website is a fast growing news portal for energy efficiency in buildings showcasing success stories, breakthrough technology or policy updates.


GreenSource magazine

Bimonthly publication on case studies and new technologies for energy efficiency in commercial buildings. 


Journal of Building Information Simulation

This is a quarterly publication for the group of energy modeling. 


Local Leaders in Sustainability- AIA 2008

This professional architects organization is a very good starting point for architects looking to start energy efficient design.


Federal Agenda for Net-Zero Energy High Performance Green Buildings – National Science and Technology Council, October 2008

Fall 2008 guideline and performance goals developed by federal government.


Energy Design Resources (EDR) Simulation Guidebooks

Information about energy-efficient building practices available in EDR's Design Briefs, Design Guidelines, Case Studies, and Technology Overviews.

Technical Guides

ENERGY STAR Building Upgrade Manual

This manual is a strategic guide for planning and implementing energy-saving building upgrades. It provides general methods for reviewing and adjusting system control settings, plus procedures for testing and correcting calibration and operation of system components such as sensors, actuators, and controlled devices.


Advanced Building Core Performance Guide

This weblink leads to NBI website to download the standard for free.


Lighting Research at RPI

State of the art lighting research center at RPI provides all information terminologies of lighting design, strategies for efficient lighting and product reviews after experimental testing. 


COMNET Commercial Buildings Energy Modeling Guidelines and Procedures

This manual offers guidance to building energy modelers, ensuring technically rigorous and credible assessment of energy performance of commercial and multifamily residential buildings. It provides a streamlined process that can be used with various existing modeling software and systems, across a range of programs.


2009 ASHRAE Handbook of Fundamentals, Chapter 19

Chapter 19 is titled, “Energy Estimating and Modeling Methods”. The chapter discusses methods for estimating energy use for two purposes: modeling for building and HVAC system design and associated design optimization (forward modeling), and modeling energy use of existing buildings for establishing baselines and calculating retrofit savings (data-driven modeling).


Treatment of Distric or Campus Thermal Energy in LEED v2 and LEED 2009 (Updated August 13, 2010)

Required reference document for DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. systems in LEED energy credits.

Software Tools

National Renewable Energy Program, Energy-10 Energy Simulation Software

 

ENERGY-10 is an award-winning software tool for designing low-energy buildings. ENERGY-10 integrates daylighting, passive solar heating, and low-energy cooling strategies with energy-efficient shell design and mechanical equipment. The program is applicable to commercial and residential buildings of 10,000 square feet or less. 

 


DOE-2, Building Energy Use and Cost Analysis Software

 

This website includes information from the developers of DOE-2 and DOE-2 products, such as eQUEST, PowerDOE, and COMcheck-Plus. 

 


DOE approved software

This is the list of all software approved by DoE that can be used to run simulation for LEED purpose. 


MOIST

This is a tool available to download for envelope moisture analysis tool.


Building Integrated Modeling

BIM is a popular design tool that allows collaboration among all team members and allows quick outputs of all analyses. 


DesignBuilder and EnergyPlus

DesignBuilder is a Graphical User Interface to EnergyPlus. DesignBuilder is a complete 3-D graphical design modeling and energy use simulation program providing information on building energy consumption, CO2Carbon dioxide emissions, occupant comfort, daylighting effects, ASHRAE 90.1 and LEED compliance, and more.


Integrated Environmental Solutions – Virtual Environment Pro / Apache

IES VE Pro is an integrated computing environment encompassing a wide range of tasks in building design including model building, energy/carbon, solar, light, HVAC, climate, airflow, value/cost and egress.

Advanced Buildings Core Performance Guide (CPG) Checklist

Option 3

This spreadsheet lists all the requirements for meeting EAp2 – Option 3 and and EAc1 – Option 3. You can review the requirements, assign responsible parties and track status of each requirement through design and construction.

Energy Simulation Narrative

Option 1

Sometimes the energy simulation software being used to demonstrate compliance with Option 1 doesn't allow you to simulate key aspects of the design. In this situation you'll need to write a short sample narrative, as in these examples, describing the situation and how it was handled.

Equipment and Product Cut Sheets

All Options

In your supporting documentation, include spec sheets of equipment described in the Option 1 energy model or Options 2–3 prescriptive paths.

PRM Table

Option 1

This is a sample building energy performance and cost summary using the Performance Rating Method (PRM). Electricity and natural gas use should be broken down by end uses including space heating, space cooling, lights, task lights, ventilation fans, pumps, and domestic hot water, at the least.

Tariff Charges

Option 1

Option 1 calculates savings in annual energy cost, but utility prices may vary over the course of a year. This sample demonstrates how to document varying electricity tariffs.

Modeled Energy Reductions

Option 1

This graph, for an office building design, shows how five overall strategies were implemented to realize energy savings of 30% below an ASHRAE baseline. (From modeling conducted by Synergy Engineering, PLLC.)

U.S. Climate Zones

All Options

The climate zones shown on this Department of Energy map are relevant to all options for this credit.

Appendix G Fan Power Calculator

Option 1

This spreadsheet, provided here by 7group, can be used to calculate the fan volume and fan power for Appendix G models submitted for EAp2/EAc1.  Tabs are included to cover both ASHRAE 90.1-2004 and 90.1-2007 Appendix G methodologies.

LEED Online Forms: CS-2009 EA

Sample LEED Online forms for all rating systems and versions are available on the USGBC website.

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

351 Comments

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Ciaran McCabe METEC Consulting Engineers
Mar 18 2017
LEEDuser Member
715 Thumbs Up

Ashrae 90.1 PRM software

I am just wondering what people's opinion is on Tranes trace software and eQuest software. The software we currently use for energy models has very poor technical support and after sales services therefore I am currently looking for alternatives that might be suitable. Looking forward to hearing options.

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Marcus Sheffer LEED Fellow, 7group Mar 19 2017 LEEDuser Expert 69162 Thumbs Up

Trane - costs money has good customer service

eQUEST - free but no customer service

Beyond that basic there are technical differences, but they are both pretty good in that regard.

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Ciaran McCabe METEC Consulting Engineers
Mar 08 2017
LEEDuser Member
715 Thumbs Up

Baseline HVAC System Selection

I am working on a 9 storey office building (8 levels of office and 1 basement level). The building has a total floor area of 9,400m2. The space heating and cooling will be provided by means of a VRF system and the primary ventilation, which will consist of DX AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork.'s will provided tempered fresh air at 18 degrees C. The ventilation system will provide 100% outside air sized on minimum fresh air requirements. Therefore the heating, Ventilation and Air conditioning will all be provided using electricity. With this is mind my question is which Baseline System should we use and which fuel types should we use. ?

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Marcus Sheffer LEED Fellow, 7group Mar 08 2017 LEEDuser Expert 69162 Thumbs Up

All electric and more than 5 stories is a System #8. See Table G3.1.1A.

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Ciaran McCabe METEC Consulting Engineers Mar 08 2017 LEEDuser Member 715 Thumbs Up

Thanks Marcus for your reply. If we were to change to an AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. which provides heating via natural gas (fossil fuel) while keeping the VRF system would this change the the Baseline System selection ?

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Marcus Sheffer LEED Fellow, 7group Mar 08 2017 LEEDuser Expert 69162 Thumbs Up

That sounds like a hybrid system so it changes to a System #7.

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Ciaran McCabe METEC Consulting Engineers Mar 10 2017 LEEDuser Member 715 Thumbs Up

That's great Marcus. If the service hot water was generated using gas and the space heating, cooling and ventilation was electricity would this be defined as hybrid. Or is service hot water irrelevant when picking the most appropriate baseline system.

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Marcus Sheffer LEED Fellow, 7group Mar 10 2017 LEEDuser Expert 69162 Thumbs Up

Only the space heating fuel matters in the selection of the Baseline system.

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Ciaran McCabe METEC Consulting Engineers Mar 13 2017 LEEDuser Member 715 Thumbs Up

Am I correct in saying that even if we had one radiator that was heated from fossil fuel in the building and everything else was electric heating - in this instance it would be still be considered hybrid system.

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Marcus Sheffer LEED Fellow, 7group Mar 13 2017 LEEDuser Expert 69162 Thumbs Up

Potentially yes. You would also check to see if any of the G3.1.1 exceptions would apply.

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Ciaran McCabe METEC Consulting Engineers Mar 13 2017 LEEDuser Member 715 Thumbs Up

Also using System #7 I feel we are being unfairly punished because our baseline system will use gas as the fuel type (System 7) and our proposed system will use electricity for the space heating and gas for the ventilation air heating. Gas is a lot cheaper than electricity therefore any saving we try and produce are diminished by the difference in fuel costs Gas Vs Elec. We have heat recovery built into all our air handling loads therefore the dominant heating fuel will be electricity. Can I obtain further clarity on this matter.

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Marcus Sheffer LEED Fellow, 7group Mar 13 2017 LEEDuser Expert 69162 Thumbs Up

No one said the system is always fair (just like life in general).

You have a very clear hybrid system. The entire building is partially heated with gas. Check out LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10285.

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Manivel Natarajan
Mar 08 2017
Guest

FAHU's Fan power and Cooling capacities

Hi All,

In my project, proposed building has DX split unit HVAC System. Fan power and cooling capacities have been modeled as per the indoor unit DX schedules.Further, fresh air is provided through FAHU's. For the baseline, indoor units fan power has been calculated as per Table G3.1.2.9, appendix G. Please clarify how I can include the FAHU’s fan power and cooling capacities in base case simulation.
The proposed FAHU's is supplying fresh air for the both base case and proposed case. If I consider, FAHU’s fan power and cooling capacities in the proposed case, proposed energy consumption is coming very high. I am unable to get energy savings even my indoor unit fan power and cooling capacities are less compared with baseline fan power calculation. Kindly clarify how I could manage for the FAHU's fan power and cooling capacities for both base and proposed simulation model.

Thanks in advance for your help.

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Marcus Sheffer LEED Fellow, 7group Mar 08 2017 LEEDuser Expert 69162 Thumbs Up

You model the Proposed systems as designed using the actual capacities and fan power in alignment with the project documents or the installed equipment if known.

You model the Baseline according to Appendix G. It is unclear from above what Baseline system type you are dealing with. In general you would not have a separate FAHU in the Baseline system. Systems 1-4 map the Proposed systems, Systems 5-8 are modeled per floor. Any G3.1.1 exceptions that apply must be modeled. If you provide some more specifics on the Baseline system I might be able to get more specific about how to model the Baseline system.

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Ciaran McCabe METEC Consulting Engineers
Jan 11 2017
LEEDuser Member
715 Thumbs Up

Baseline HVAC System Selection

Hi,

I have a LEED project that is split up into 3 separate blocks. Each block is made up of mainly office space. On the ground floor there is retail units. In selecting the correct baseline system I have used Table G3.1.1A and G3.1.1B. Using the building type, number of floors etc I have determined that the most suitable baseline is System 7. This is assigned to the whole building including the retail within the baseline model. Can the retail use the same baseline as I see a note under Table G3.1.1A which states "Where attributes make a building eligible for more than one baseline system type, use the predominant condition to determine the system type for the entire building" . Is one system type for the entire baseline building the correct approach ?

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Marcus Sheffer LEED Fellow, 7group Jan 11 2017 LEEDuser Expert 69162 Thumbs Up

The one system type may apply in your situation or it might not. Make sure to follow the guidance in Section G3.1.1 and not just in the tables G3.1.1A/B. The retail space in your case may qualify for one of the G3.1.1 exceptions. If any exceptions apply you must include them in your model. Be sure to model the baseline with a system per floor and not the same as the proposed design. This can get complicated in some cases but in your case it seems pretty simple.

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Ciaran McCabe METEC Consulting Engineers Jan 11 2017 LEEDuser Member 715 Thumbs Up

Thanks Marcus for your reply. After reading the exceptions 3 of the 4 definitely do not apply. I don't think point (B) applies either because I don't think that the thermal loads in the retail will differ by 31 W/m2 from the average of the other spaces (offices). Retail will have higher occupancy hours per week but not by a factor of 40 hours as referenced with this exception (b). Would I be right in saying this exception directed more towards spaces that operate almost 24/7 ?

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Marcus Sheffer LEED Fellow, 7group Jan 16 2017 LEEDuser Expert 69162 Thumbs Up

That certainly could be the case.

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Ciaran McCabe METEC Consulting Engineers
Jan 09 2017
LEEDuser Member
715 Thumbs Up

Boiler Thermal Efficiency (%)

Is there a formula for calculating the Boiler Thermal Efficiency using HHV. Should the modeled boiler efficiency be seasonal taking into account part load conditions. Is there any ASHRAE / LEED reference ?

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Marcus Sheffer LEED Fellow, 7group Jan 11 2017 LEEDuser Expert 69162 Thumbs Up

You don't use a seasonal efficiency value. You use the boiler efficiency at rated conditions under 10 CFRCurrent facilities requirements: the implementation of the owner's project requirements, developed to confirm the owner's current operational needs and requirements. part430/431. Then there is a boiler efficiency curve applied which contains the part-load efficiency.

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Jeff Riggs
Nov 14 2016
Guest
7 Thumbs Up

Air economizer in baseline model

Project Location: United States

If your climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. does not require air econmizer for baseline systems (90.1 2007, climate zone 4a) are you allowed to model your proposed systems with economizerAn economizer is a device used to make building systems more energy efficient. Examples include HVAC enthalpy controls, which are based on humidity and temperature., per design and not have economizer in baseline systems?

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Marcus Sheffer LEED Fellow, 7group Nov 15 2016 LEEDuser Expert 69162 Thumbs Up

Yes. You pretty much always model the Proposed as designed and the Baseline according to Appendix A.

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Ciaran McCabe METEC Consulting Engineers
Nov 02 2016
LEEDuser Member
715 Thumbs Up

v2009 Min. Performance Calculator - Service Hot Water Inputs

With reference to Service Hot Water should the following baseline inputs match the proposed;

If not where can I find good guidnace on how these baseline inputs can be obtained.

Baseline Inputs
Storage Volume (L)
Storage Temperature (deg C)
Peak Hot Water Demand (L/s)
Number of Pumps
Total Pump Power

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Marcus Sheffer LEED Fellow, 7group Nov 02 2016 LEEDuser Expert 69162 Thumbs Up

Yes typically. You can claim savings related to HW demand if you can demonstrate low flow fixtures and/or appliances.

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Ciaran McCabe METEC Consulting Engineers
Oct 18 2016
LEEDuser Member
715 Thumbs Up

Energy Model For A Campus

Hi,

I am working on a Leed campus project where there is 3 separate buildings which each consist of retail units on the ground floor and office units above. There is two levels of mechanically ventilated car park below which is common to all buildings. In order to report savings for this credit do we separate each building as a separate model and if so which results would we use.

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Marcus Sheffer LEED Fellow, 7group Oct 23 2016 LEEDuser Expert 69162 Thumbs Up

If the LEED project boundary includes all three buildings and they are connected according to the MPRs then you model all three together as one building.

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Ciaran McCabe METEC Consulting Engineers
Oct 05 2016
LEEDuser Member
715 Thumbs Up

Min Chiller Efficiency

I am trying to establish the minimum chillier efficiency we are permitted to use in our PRM model. We have spec'd an air cooled chiller. In terms of understanding the minimum efficiency permitted do we just refer to ASHRAE 90.1 Table 6.8.1C. The baseline chiller in our model will be a water cooled chiller. Are we allowed to use a baseline chiller efficiency that is higher (in terms of COP) than the proposed chiller in our model ? Any feedback here would be great.

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Marcus Sheffer LEED Fellow, 7group Oct 05 2016 LEEDuser Expert 69162 Thumbs Up

Yes that sounds like the correct table.

Yes you should use the chiller COP for the baseline system even if it is higher than your proposed chiller. You pay a penalty for using a less efficient chiller.

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jorge torres coto Building Systems Commissioning Engineer Empirical Engineering, LLC
Sep 19 2016
LEEDuser Member
647 Thumbs Up

Appendix G Oversizing

Project Location: Mexico

I have a reviewer requesting that we oversize the PROPOSED case for a "possibly conditioned in the future" warehouse.
We have usually modeled the BASELINE case and PROPOSED case identical, then oversized the cooling and heating for the BASELINE by 1.15 and 1.25 respectively.
On this project, for some reason, he/she is requesting that we oversize the PROPOSED also "to make them identical"
My question is: is the identical requirement in Table G3.1 section 10.c & d prior to taking into account section G3.1.2.2 Equipment Capacities, or does it simply not apply when we have nothing defined. Or an erroneous interpretation on the reviewers part.

I do not have a USER'S MANUAL, that may explain it a little better, so I am also interpreting the way I have an all my previous project.

My interpretation is the Systems are identical, though the Capacities are adjusted in the BASELINE (oversized)

Thanks
Jorge

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Marcus Sheffer LEED Fellow, 7group Sep 19 2016 LEEDuser Expert 69162 Thumbs Up

Identical is modeled identically in all respects. Without a design the Proposed would also be over-sized identically according to G3.1.2.2. Think of it this way, since you do not have a proposed design you have to include the baseline system just as you would in the baseline. With that said there may be a sizing difference between the systems in the two models since both are auto-sized and it may be possible that the envelop and/or lighting are different.

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Ciaran McCabe METEC Consulting Engineers
Sep 07 2016
LEEDuser Member
715 Thumbs Up

Baseline Fenestration - Existing Buildings

How should one model existing glazing U-Values and Solar Heat Gain values when they are unknown (they were installed 24 years ago). I am referring to the Baseline Model ASHRAE Table G3.1 5f

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Marcus Sheffer LEED Fellow, 7group Sep 08 2016 LEEDuser Expert 69162 Thumbs Up

There are a few ways. Try to find the performance data on the old windows. The data can be determined through measurement. Use Table A8.2 from ASHRAE 90.1-2007.

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SI CHEN
Jul 12 2016
Guest
129 Thumbs Up

Supporting Documents for EAp2 and EAc1

Hi all,

I am working on a LEED 2009 NC project with IES energy modelling. Could anybody advise what documents need to be submitted for EAp2 and EAc1 certifications?

I suppose BPRM report is enough. But I wonder if the 'minimum energy performance calculator' excel sheet is still needed. Thanks!

Si

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Marcus Sheffer LEED Fellow, 7group Jul 12 2016 LEEDuser Expert 69162 Thumbs Up

The reporting we see from IES typically looks like the very old summary report that was used for LEED v2.2 projects. It provides a reasonable summary of the envelop and lighting but is usually blank on HVAC. It is not a substitute for the required Section 1.4 tables or the new calculator.

In general projects should provide reports that confirm the input data entered in the spreadsheets.

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MKK LEED
May 18 2016
LEEDuser Member
240 Thumbs Up

Central Plant - Condenser Loop

Project Location: United States

We are working on a project with two buildings on one site, one commercial C&S, one Hotel. The two buildings are sharing some thermal plant, but it is only a condenser water loop – one central cooling tower set, one boiler plant to boost the loop. Both systems will be water source heat pumps, but separate submissions for LEED (and code).

I reviewed the "Treatment of District or Campus Thermal Energy in LEED" document to try to determine how I should submit my project, but it has made me more confused. The campus document talks about a DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. as being a system that provides thermal energy “heating via hot water or steam, and/or cooling via chilled water”. Since this is neither, and following the Option 1 path will drive both baseline and proposed farFloor-area ratio is the density of nonresidential land use, exclusive of parking, measured as the total nonresidential building floor area divided by the total buildable land area available for nonresidential structures. For example, on a site with 10,000 square feet (930 square meters) of buildable land area, an FAR of 1.0 would be 10,000 square feet (930 square meters) of building floor area. On the same site, an FAR of 1.5 would be 15,000 square feet (1395 square meters), an FAR of 2.0 would be 20,000 square feet (1860 square meters), and an FAR of 0.5 would be 5,000 square feet (465 square meters). from what is actually in the buildings, should we just ignore the central plant and treat them as separate water loops? There are theoretical energy savings from putting two buildings with different profiles on the one loop, and capacity reductions obviously, but using the guide doesn't seem any kind of logical.

I am leaning towards just giving each building a separate loop, but this won't match the drawings, I want to be sure that GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). will actually accept the approach I take.

Thanks

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Marcus Sheffer LEED Fellow, 7group May 24 2016 LEEDuser Expert 69162 Thumbs Up

No treating them as separate loops is not the best way to proceed.

You should apply DESv2 Option 2. You will need to model both buildings together to determine the plant efficiency and then produce separate modeling results that apply the efficiency of the plant. You can do this all within one model by creating separate meters and proportioning the loads on the plant to each building.

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MKK LEED May 24 2016 LEEDuser Member 240 Thumbs Up

Hi, I can do the separate meters to achieve that, but in the DESv2 guide it says that for Opt2 my proposed district heating should be a virtual on site hot water or steam system, and my cooling should be a virtual on site chiller. I don't have a chiller on my site, and the boiler is only to top off the condenser loop, so what they want me to model will not represent my actual building.
I have now been pointed to a LEED interpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. (ID# 5234) that deals with a similar system, though they have geothermal in addition to the cooling tower and boiler. The interpretation states that "It appears, based on the description, that the building does not fall under the District Energy requirements, in that it is not provided with cooling or heating from a district source, but rather provided with condenser water which feeds heat pumps that produce the cooling and heating within the building." Based on this it is exempt from the DES guide, which would support just ignoring the shared plant. Unfortunately this referenced v1 of the DES guide so I'm unclear if it is still relevant, it does say it is also applicable to LEED2009.

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Marcus Sheffer LEED Fellow, 7group May 24 2016 LEEDuser Expert 69162 Thumbs Up

I would suggest you apply the principles espoused by the DESv2 and not get hung up on the specific words. I agree it is not a perfect fit but if you apply the principle that you are proportioning the loads used from the shared loop it is basically the same as having a virtual on-site system.

You may be able to make the case that your system is not covered by the DES and not use it. This however will be considerably harder to do because you will then need to prepare a rather extensive justification for the modeling method you do apply if it is not in alignment with the DESv2. If you do choose this path it would be a good idea to submit a project specific CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide.

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MKK LEED May 24 2016 LEEDuser Member 240 Thumbs Up

So I can interpret the virtual onsite system that provides hot and chilled water as a virtual onsite system, but one that doesn't necessarily supply at boiler and chiller temperatures? I suppose it does say representing the upstream DH and DC systems, and since mine is condenser water that can be my represented plant. I have no problem with the combined model with meters in general. Thanks for the help

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Marcus Sheffer LEED Fellow, 7group May 24 2016 LEEDuser Expert 69162 Thumbs Up

Yes you can and the intention is clearly for you to represent your upstream plant.

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Ciaran McCabe METEC Consulting Engineers
May 12 2016
LEEDuser Member
715 Thumbs Up

Annual Equivalent Full Load Hours of DHW Operation

Hi, In relation to Table 1.4 where can one get "Annual Equivalent Full Load Hours of DHWDomestic hot water (DHW) is water used for food preparation, cleaning and sanitation and personal hygiene, but not heating. Operation". Is this something I need to calculate or is it a standard value ?

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Marcus Sheffer LEED Fellow, 7group May 12 2016 LEEDuser Expert 69162 Thumbs Up

You derive this value by dividing the annual energy use by the annual peak demand.

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Ciaran McCabe METEC Consulting Engineers
May 11 2016
LEEDuser Member
715 Thumbs Up

Baseline Fenestration

How does one know what baseline glazing type to model. Table 5.5-5 list various Fenestration types but it is not clar which one should be used. Maybe somebody can clarify ?

Thanks.

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Marcus Sheffer LEED Fellow, 7group May 11 2016 LEEDuser Expert 69162 Thumbs Up

Use the one that corresponds to the windows in the design. If you have more than one type in the design you will have more than one type in the baseline model. So if you have wood framed windows use nonmetal framed, if you have curtainwall use that one, etc.

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Ciaran McCabe METEC Consulting Engineers May 11 2016 LEEDuser Member 715 Thumbs Up

Many thanks Marcus for your guidance.

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Ciaran McCabe METEC Consulting Engineers
Apr 21 2016
LEEDuser Member
715 Thumbs Up

Baseline HVAC System

We are using packaged VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with reheat system 5 for the Baseline System. In sizing the baseline heating coils and fans within this system should the air flow rates and and on coil / off coil temperatures match the proposed building system.?

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Marcus Sheffer LEED Fellow, 7group Apr 25 2016 LEEDuser Expert 69162 Thumbs Up

The airflow rates are auto-sized along with the heating capacity. See G3.1.2.2 for equipment capacities, G3.1.2.8 for airflow rate/temperatures, and G3.1.2.9 for fans. The room temperature settings should be identical to the proposed.

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Ciaran McCabe METEC Consulting Engineers May 08 2016 LEEDuser Member 715 Thumbs Up

Thanks Marcus. Just wondering should the Outside Air supply rate be the same for the proposed and baseline rooms modeled ?

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Marcus Sheffer LEED Fellow, 7group May 09 2016 LEEDuser Expert 69162 Thumbs Up

Unless the proposed has demand controlled ventilation the total outside air should be in the same in both models. Since you do not necessarily create a model on a room-by-room basis I am not sure it translates down to the room level. A system #5 according to G3.1.1 must be modeled as a system per floor. So the OA for that system on that floor should correspond to the total outside air of the proposed systems serving that floor.

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Ward Miller Chief Environmental Officer Alpenglow Advisory
Apr 01 2016
LEEDuser Member
887 Thumbs Up

Modeling a curtain wall

Theoretically one might think modeling the glazing and shadowbox portions of a curtain wall with a single assembly u-valueU-value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The greater the U-value, the less efficient the building element is as an insulator. The inverse of (1 divided by) the U-value is the R-value. would yield the same result as modeling the curtain wall as glazing for the transparent part and external wall for the shadowbox, both with independent assembly u-values. Has anyone ever tried comparing such a scenario and what result was achieved?

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Marcus Sheffer LEED Fellow, 7group Apr 02 2016 LEEDuser Expert 69162 Thumbs Up

All things being equal you should get the same result.

Typically however there is additional material and/or insulation behind the spandrel panels so the two scenarios are usually not equal.

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Ciaran McCabe METEC Consulting Engineers
Feb 11 2016
LEEDuser Member
715 Thumbs Up

Site Obstructions & Shading

Is it recommended to include adjacent buildings to represent the shading effects in the proposed model. If so do I assume that I also include it in the baseline model also.

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Marcus Sheffer LEED Fellow, 7group Feb 11 2016 LEEDuser Expert 69162 Thumbs Up

I think it is a good idea if it is likely to have a significant impact on the energy use. It is just good practice to model a projects as accurately as possible.

In 90.1-2010 you are required to include these features according to Table G3.1-14. They get modeled identically.

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Ciaran McCabe METEC Consulting Engineers
Feb 11 2016
LEEDuser Member
715 Thumbs Up

Service Hot Water Consumption

Hi, Is there any guidance on what service hot water consumption should be used in the energy model in USgal/h.pers or Lts/day/ person. What would USGBC look out for here ? Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Feb 11 2016 LEEDuser Expert 69162 Thumbs Up

There is general guidance in the ASHRAE Applications Handbook, Chapter 50.

The reviewers will look for consistency with the calculations in WEp1 which may help in determining the appropriate values to use as well.

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Ciaran McCabe METEC Consulting Engineers
Jan 26 2016
LEEDuser Member
715 Thumbs Up

Power Adjustment Percentages for Automatic Lighting Controls

Hi,

I am producing an energy model for a a refurbished building with a new lighting scheme. The installed LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. is 9 Watts /m2 using LED. As the new lighting design includes occupancy sensors and programmable timing control am I correct in saying that I can reduce the installed LPD in my model by 10% by applying ASHRAE 2007 90.1 Table G3.2. For example use 8.1 W/m2 in the model as opposed to 9w/m2. Any advise on this would be great.

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Marcus Sheffer LEED Fellow, 7group Jan 26 2016 LEEDuser Expert 69162 Thumbs Up

Yes that is correct. Make sure you also include occupancy sensors in the baseline where required by Section 9.4.1.2.

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Ciaran McCabe METEC Consulting Engineers
Jan 13 2016
LEEDuser Member
715 Thumbs Up

PRM Modelling Queries

Hi,

I have 2 questions in relation to the 90.1 Energy Model.

1) Is Dublin (Ireland) in ASHRAE climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. 5 or 5a.

2) The building to be modeled is a 5 storey building with a basement. The basement is unconditioned but has some artificial lighting. Does the basement need to be included in the PRM model. Do I need to add up the total wattage for all the basement lights and include this in the model. The basement also has a few toilets / showers but this is a small percentage of the overall area.

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Marcus Sheffer LEED Fellow, 7group Jan 13 2016 LEEDuser Expert 69162 Thumbs Up

1. All climate zones are either a, b, or c. See Appendix B2.

2. You should model the basement. The interior lighting must be modeled and you need to assign it to a space. You also need to accurately model the thermodynamics and there is a difference between a basement and a slab. Hard to believe that the basement shower area is unconditioned. If even a small portion of the basement is conditioned it counts as a floor (story).

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Ciaran McCabe METEC Consulting Engineers Jan 13 2016 LEEDuser Member 715 Thumbs Up

Thanks Marcus. Table B3 "International Climate Zones" has Dublin down as Climate zone 5. Do I need to further refine this in terms of A, B, C based on local climate i.e. cool humid, dry, marine. ?

Your advise would be gratefully received.

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Marcus Sheffer LEED Fellow, 7group Jan 13 2016 LEEDuser Expert 69162 Thumbs Up

You only need to do so for certain items like the economizerAn economizer is a device used to make building systems more energy efficient. Examples include HVAC enthalpy controls, which are based on humidity and temperature. high limit cut off for example. So for a climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. 5, yes you have to determine which one you are.

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Ciaran McCabe METEC Consulting Engineers Jan 22 2016 LEEDuser Member 715 Thumbs Up

Is there any guidance on how infiltration (HVAC) uncontrolled inward air leakage to conditioned spaces through unintentional openings in ceilings, floors, and walls from unconditioned spaces or the outdoors caused by the same pressure differences that induce exfiltration. (ASHRAE 62.1-2010)/ leakage through the fabric should be set in both the baseline & proposed models. We are upgrading the fabric in our building and therefore we aim to achieve better air tightness.

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Marcus Sheffer LEED Fellow, 7group Jan 22 2016 LEEDuser Expert 69162 Thumbs Up

I assume the fabric you refer to is the building wrap material. Unfortunately a baseline has not been established for air tightness so there is not a mechanism in place to claim savings.

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Ciaran McCabe METEC Consulting Engineers Jan 22 2016 LEEDuser Member 715 Thumbs Up

Thanks Marcus.

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Ciaran McCabe METEC Consulting Engineers
Dec 15 2015
LEEDuser Member
715 Thumbs Up

Baseline Model Inputs

For the baseline model can I please confirm the following;

Design Cooling SAT: According to ASHRAE 90.1 G3.1.2.8 should the supply temperture be 11 deg C less than room temp. Is this correct ?

Is the any guidance on what should be used for heat / coil off coil temps

What is the supply fan min flow that should be used for baseline

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Marcus Sheffer LEED Fellow, 7group Dec 15 2015 LEEDuser Expert 69162 Thumbs Up

Correct.

No guidance on the heating side for most systems. Exception is a system 9 or 10, heating only system.

It depends on the baseline system. See sections G3.1.2.8, G3.1.3.13, and G3.1.3.14 for requirements that affect the supply minimum flow.

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Ciaran McCabe METEC Consulting Engineers
Dec 14 2015
LEEDuser Member
715 Thumbs Up

Baseline Construction Performance

When modelling the Baseline where the building is existing (not a new build) what is the procedure for selecting the baseline constructions in the model. This building is outside the US. Do we need to refer to ASHRAE 90.1 baseline constructions and if so how do we know which ones to choose.

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Marcus Sheffer LEED Fellow, 7group Dec 14 2015 LEEDuser Expert 69162 Thumbs Up

The Baseline constructions are defined in Table G3.1#5Baseline. For an existing building see G3.1#5Baseline(f).

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Ciaran McCabe METEC Consulting Engineers Dec 14 2015 LEEDuser Member 715 Thumbs Up

Many thanks Marcus. I think you are referring to ASHRAE 90.1 2010. We are working to the 2007 ASHRAE. Does this change things ?

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Marcus Sheffer LEED Fellow, 7group Dec 14 2015 LEEDuser Expert 69162 Thumbs Up

I was referring to 2007. Both versions are identical on this issue.

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