USGBC's membership approved an update to LEED 2009 effective April 8, 2016. The update only affects LEED 2009 projects registered on or after that date.
Project teams will be required to earn a minimum of four points in EAc1, effectively making part of this credit a prerequisite along with EAp2. The referenced energy standard and modeling requirements are not changed. Buildings falling under the proposed change can use the same methodologies and referenced standards, but will need to earn additional points in order to achieve certification.
The intent of the change is to bring LEED 2009 energy requirements more up to date, as LEED 2009 continues to be the predominant LEED rating system, even though the more up-to-date LEED v4 has also become available.
EAc1: Optimize Energy Performance is, by far, the most important credit in LEED, based on the number of points available. Up to 19 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.
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.)
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.
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.
If you want to aim for higher targets of 20%–50% energy savings or higher, consider measures such as the following.
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.)
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.
If your project is connected to a district energy system, 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.)
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.
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.
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.
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.
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.
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.
Develop multiple iterations of your project design to analyze the energy impact of each change.
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:
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:
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.
Follow EAp2 steps for compliance and documentation.
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:
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.
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.
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.
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.
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.
Finalize the list of strategies adopted from Section 3. Your project earns one point for three strategies, two points for six strategies.
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.
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.
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.
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.
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.
Excerpted from LEED 2009 for New Construction and Major Renovations
To achieve increasing levels of energy performance beyond the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use.
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.
Demonstrate a percentage improvement in the proposed building performance rating compared with the baseline building performanceBaseline building performance is the 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:
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:
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.
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.
The building must meet the following requirements:
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:
Points achieved under Option 3 (1 point):
Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
1Project 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 identified in the LEED 2009 Green Building Design and Construction Global ACP Reference Guide Supplement.
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
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.
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 equivalentstandard using the process located at www.usgbc.org/leedisglobal.
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.
ASHRAE offers guidance for different levels of building energy audits.
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.
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 is a joint program of U.S. EPA and the U.S. Department of Energy that promotes energy-efficient buildings, products, and practices.
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.
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.
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.
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.
Non-profit organization aiming at design community to increase collaboration for designing energy efficient buildings.
International association of energy modelers with various national and local chapters.
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.
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.
This online resource, supported by Natural Resources Canada, presents energy-efficient technologies, strategies for commercial buildings, and pertinent case studies.
This website provides details process to develop an energy model.
Research warehouse for strategies and case studies of energy efficiency in buildings.
An online window selection tool with performance characteristics.
DOE website with database of energy performance of buildings across US.
This website lays out design process for developing an energy efficient building.
This website is put together for architects with ideas on hundreds of ways to improve design for lower energy demand.
This document lists multiple web based or downloadable tools that can be used for energy analyses.
This webtool is a database of strategies and vendors for energy efficient systems.
Energy design tools are available to be used for free online or available to download.
This website lists performance characteristics for various envelope materials.
This is an online forum of discussion for energy efficiency, computer model software users.
This directory provides information on 406 building software tools for evaluating energy efficiency, renewable energy, and sustainability in buildings.
Weather data for more than 2100 locations are available in EnergyPlus weather format.
Weather data for U.S. and Non-U.S. locations in BIN format.
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.
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.
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.
These guidelines are available as a free download or can be purchased as a printed manual of 390 pages.
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.
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.
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.
This ongoing project explores the effects of computers and other information technology on resource use.
The Handbook provides up-to-date coverage of lighting development, evaluation and interpretation of technical and research findings, and their application guidelines.
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.
This manual covers nearly all disciplines involved in the design, construction and operation of green buildings.
This website is a fast growing news portal for energy efficiency in buildings showcasing success stories, breakthrough technology or policy updates.
Bimonthly publication on case studies and new technologies for energy efficiency in commercial buildings.
This is a quarterly publication for the group of energy modeling.
This professional architects organization is a very good starting point for architects looking to start energy efficient design.
Fall 2008 guideline and performance goals developed by federal government.
Information about energy-efficient building practices available in EDR's Design Briefs, Design Guidelines, Case Studies, and Technology Overviews.
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.
This weblink leads to NBI website to download the standard for free.
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.
This document is USGBC’s second (v2.0) major release of guidance for district or campus thermal energy in LEED, and is a unified set of guidance comprising the following an update to the original Version 1.0 guidance released May 2008 for LEED v2.x and the initial release of formal guidance for LEED v2009.
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.
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).
Required reference document for DES systems in LEED energy credits.
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.
This website includes information from the developers of DOE-2 and DOE-2 products, such as eQUEST, PowerDOE, and COMcheck-Plus.
This is the list of all software approved by DoE that can be used to run simulation for LEED purpose.
This is a tool available to download for envelope moisture analysis tool.
BIM is a popular design tool that allows collaboration among all team members and allows quick outputs of all analyses.
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.
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.
Sample LEED Online forms for all rating systems and versions are available on the USGBC website.
In your supporting documentation, include spec sheets of equipment described in the Option 1 energy model or Options 2–3 prescriptive paths.
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.
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.
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.
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.
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.)
The climate zones shown on this Department of Energy map are relevant to all options for this credit.
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.
Documentation for this credit can be part of a Design Phase submittal.
I am working on my first LEED modelling work with IES and wondering what documents are needed for the submission for EAp2 and EAc1. I suppose it should include 1) BPRM Report from IES and 2) v2009_Minimum Energy Performance Calculator (Section 1.4 Table). Can anybody give me some ideas? Many thanks!!
The input summary reports from IES-VE are sorely lacking when it comes to summarizing the HVAC inputs. So that makes it doubly important to fill out the calculator input summaries as accurately as possible. As far as I know those two items are all you can submit. The only other thought I have would be to provide screen captures in a separate report that summarizes the IES-VE HVAC inputs, especially if anything is even slightly anomalous and needs some further explanation than is provided in the calculator.
The BPRM and Table 1.4 are all I typically provide for the first submission unless we are modeling something odd that requires further explanation. I agree with Marcus about the input reports though. You want to be as detailed and clear as possible in filling out table 1.4 because the lack of HVAC inputs. Then I provide screen shots based on specific questions in the review comments rather than taking a screen shot of everything for the initial review.
We have a project that is part of a campus and has a significant PV array that offsets about 35% of the building's energy costs. However, the generated electricity does not go directly to the building. Rather, the campus management has a sub group that holds the RECs. The intention here is to buy other RECs to replace the renewable energy produced by the on-site PV panel.
My question is, can I count the energy generated by the on-site panels towards EAp2 "Minimum Energy Performance" and EAc1 "Optimize Energy Performance"? If not, can the RECs purchased to replace that energy be counted towards these credits?
I found a 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 for EAc2 "On-Site Renewable Energy" explains that in a similar situation, it seems that we need to buy twice as much RECs in order to have the RECs count towards the project. In their explanation, LEED says this is due to the difference in costs/incentives of producing RECs across state borders (I don't really get it). A later CIR issued 8/21/2009 (http://www.usgbc.org/content/li-2594) backtracked and indicated buying RECs for 100% of the generated energy is enough. However, these CIRs aren't clear about using the energy for EAc1.
You can count the renewable energy toward EAc1. The owner needs to allocate a portion (or all) of the output of the campus system to this project and it can't be counted for any other project. If the RECs have not been retained and need to be replaced you need to only replace 100%. If you do these things you can count it toward EAc1 and EAc2. Purchasing RECs in general do not apply to these ceredits beyond the replacement requirement.
Thanks a million Marcus!
Is there any reference you can direct me to? I'd like to make a strong case in the event I get any questions from the reviewer or client/design team. I tried the reference guide for 2009 and looked up the CIRs on the website but couldn't find any material I can reference.
If you look at the prerequisite form for EAp2 (which determines your EAc1 points), Section 1.8 is where you enter the renewable energy production. You will not get any question from the reviewer as long as there is clear allocation, RECA Renewable Energy Certificate (REC) is a certificate representing proof that a given unit of electricity was generated from a renewable energy source such as solar or wind. These certificates are able to be sold, traded, or bartered as environmental commodities, where an electricity consumer can buy the renewable energy attributes of electricty to support renewable energy, even if they are consuming generic grid-supplied electricity that may be supplied by nonrenewable sources. ownership or replacement, and the calculation of production is reasonable.
Awesome, thanks Marcus!
We have a LEED v2009 C&S project in Germany now. LEED asks for energy simulation according to ASHRAE Standard for the Prerequisite Minimum Energy Performance and Credit Optimized Energy Performance. Considering that the project is located in Germany, can the Standard DIN V18599 be an acceptable alternative for LEED? The detailed name of DIN V18599 is Energetic evaluation of buildings - Calculation of the net, final and primary energy demand for heating, cooling, ventilation, domestic hot water and lighting. (https://www.beuth.de/en/pre-standard/din-v-18599-11/142651548)
The calculations are made for examining compliance with the german national Energy Saving Law. After the simulation and calculation, each project will get a Energy Saving Law Certificate, so called "EnEV Nachweis" in german, which shows the percentage in which the designed building is better than the reference building. Information about primary energy consumption, end energy and energy sources are also available.
Since our engineers have few ideas about the ASHRAE standard, I would like to know if we can use DIN V18599 instead of ASHRAE, and provide the Energy Saving Law Certificate as the submittal.
Thank you in advance.
No. The standard you reference would need to demonstrate equivalency with 90.1. The LEED European ACPs document on page 78 spells out what needs to be done to do so. You may find other more local standards referenced for other credits.
We have a project opting to get the maximum 19 credit points in EAc1. The project is being served by a District Cooling Plant.
If the project will use the DES Option 1 (Downstream EquipmentDownstream equipment consists of all heating or cooling systems, equipment, and controls located within the project building and site associated with transporting thermal energy into heated or cooled spaces. This includes the thermal connection or interface with the district energy system, secondary distribution systems in the building, and terminal units. only) which limits the project to 10 points, can we still get the 19 points for EAc1 by providing a lot of renewables (Solar PV and Thermal Systems) to maximize energy savings.
This strategy was not clearly defined in DES Guideline and thus checking this out here in LEED User.
If we push the project to Net Zero (LEED Platinum by Default), How will the DES Guideline be used for maximizing the LEED Credit Points just by using DES Option 1?
Ref: Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 – Design and Construction
Will the approach still be the same for LEED V4?
Answered in the EAp2 forum.
we are doing LEED NC project for data center which one is correct base case LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. for data center in building area method
which lighting categories we take if we go with space by space method (For Server rooms)
Kindly tell a specific categories in ASHRAE 90.1.2007 for both build area and space by space method
Data centers were not well covered by 90.1-2007. None of the BAM facilities seem to apply. The closest I can see might be an equipment room in a manufacturing facility. You might also do some extrapolation from 90.1-2010. I think it covers data centers but the LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. values went down. So if you extrapolate some of the common areas to determine how much the LPD went down and then applied that to the data center values you may be able to justify that as a baseline.
In a previous post titled "DES Energy Cost" dating back to May 13, 2013, my interpretation of the responses in the thread is that a project can choose to either follow 90.1 or the DES Guidance from LEED for determining energy rates applied in a project that is served by a district system. Up until finding this comment thread, my understanding had been that if a project was served by a DES it was required to follow the district guidance document published by LEED. Does anyone know if it is still the case that applying the DES Guidance is optional and a project team could instead choose to follow rules in 90.1? If so, what section of documentation or what 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. would one use to come to this conclusion?
The DES has always been optional because it was not included in the credit language until v4. You could always use 90.1 Appendix G addenda. There might be an interpretation on this but I would have to go dig for it.
In lieu of following DESv2, the project team may choose to follow ASHRAE 90.1 2007 Appendix G modeling protocols, with or without ASHRAE 90.1 2007 addendums, e.g., addendum ai. If following ASHRAE 90.1 2007 district energy modeling protocols, without addenda, the heating source must be included in the energy models as purchased steam using identical energy rates in the baseline and proposed case energy models as indicated in ASHRAE 90.1 2007 Section G220.127.116.11, and the cooling energy must be modeled using purchased energy rates in the proposed case and the appropriate Appendix G baseline cooling system in the baseline case. If applying ASHRAE 90.1 2007 addendum ai, refer to ASHRAE 90.1 2007 addendum ai, Sections G18.104.22.168.1 through G22.214.171.124, for heating and cooling energy requirements. Any ASHRAE 90.1 2007 addenda implemented must be applied in whole and consistently among all LEED credits and prerequisites and the submittal documentation must clearly indicate any addenda that have been applied to the project documentation.
Hi, I just read requirement of EAc1 on USGBC web page, is it true that all LEED New Construction projects registered after 8 April 2016 have to reach 18% - 4 points at minimum. So projects have energy saving less than 18% will not be able to obtain LEED certificates? I see LEED CS doesn't apply this rule. If I submited energy saving 18% to 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). and then had to revise as per LEED reviewer, but the final result going down, less than 18%, would my project fail LEED?
Thanks for your confirm
Thanks Marcus, that's a big challenge for my garment factory which uses evaporative cooling with cooling pad, and have a lot of process load. Basically, the proposed case ventilation has just fan and pump, no air conditioning system. What would the baseline be for my factory? Will the baseline be one of 8 systems in ASHRAE or it is simply fan and pump as my proposed case?
Are there any conditioned spaces? What is being pumped for HVAC?
The water is pumped and sprayed on the top of cooling pads. The hot air outside is drawn through the wet pads, cool down, coming through the space and drawn out of the factory by exhaust fans located on the opposite wall. I don’t think the factory area is simply mechanically ventilated. I think it is likely conditioned. Since 18% saving is high enough so I really need to identify the baseline. Will it be one of 8 AC system as per ASHRAE90.1 or just fan and water pump (to spray water on the pads). Your advice on selecting baseline type is highly appreciated.
If it is considered conditioned (see definitions in 90.1) then yes you would select the appropriate system from Table G3.1.1A for the baseline.
Has anybody have experience in working on a large warehouse connected with a small office building?
I imported two baseline constructions, one is semiheated for warehouse, the other is non-residential for office building.
When I run room calculations, it shows an error 'instability in room xxx'. I guess that is because of the different building types connected together?or some other reasons? Could anybody give me some advice? Many thanks.
I would suggest you post this to the IESVE forum on their website or to the BLDG-SIM (email@example.com) since this is more of a software and modeling question than a LEED one.
I have modeled a proposed building including PV and solar thermal systems.
The energy generated of PV system is excluded of End Uses results, but the energy generateds of Solar thermal is integrated in DHWDomestic hot water (DHW) is water used for food preparation, cleaning and sanitation and personal hygiene, but not heating. system and it is subtracted of DHW energy consumption.
So, I include only PV energy generated in Table L-1 of LEED Template, i don´t include the energy generated by Solar Thermal.
However i include PV and Solar thermal energy in LEED Templated of EAc2.
Is the right approach?
Secondly, the reviewer request me to justify calculations of renewable energy generation. The calculations are based in Energy simulation results (Energy Plus).
My answer must be that renewable generation is based on Energy Simulation? and inform you thet see the results of renewable energy generated in Annual Building Utility Performance Summary (Energy Plus)?
Is the right approach?
I'll answer in the EAp2 forum. No need to post the same question in multiple forums.
I am working on a large warehouse building with a small office building on the site.
The warehouse is heated only, so I suppose that is semiheated space, is that right?
While the office building is conditioned by VRF system.
Here is the question, when I import the Ashrae Baseline Constructions, I am confused which building type I should choose, semiheated or non-residential? Should it based on the dominant space?
If I select the non-residential type, the proposed heating demands are much higher than the baseline case.
If I select the semiheated type, IES told me that 'Failed to import the following baseline constructions to the project - Above Grade Wall'.
Could anybody give me some advice? Many thanks in advance!!!
First you need to check whether your space is a heated space or a semiheated space based on the definitions. See Table 3.1 for heated space thresholds per 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.. If it turns out that your space is classified as heated, then it is considered to be a conditioned space. You will only need the conditioned space baseline constructions then. If you do have a semiheated space, then you will need both sets of constructions.
Many thanks for your advice!
According to Table 3.1, the warehouse is semiheated and office is conditioned. So I suppose I need to import two sets of baseline constructions, i.e. semiheated and non-residential, is that right?
Then I came across another problem, IES did not allow me to import the baseline constructions for semiheated type. There is an error showing 'Failed to import the following baseline constructions to the project: - Above Grade Wall'. Have you had such a problem before? I have no idea how to solve it...Thanks.
I tested importing the semi-heated constructions in a test VE2016 project, and it worked without an error. You could check with IES support or just use the ASHRAE construction wizard to import the appropriate ones since you will have to manually assign them to the right surfaces in the baseline.
Many thanks for your reply.
I also tried it in IES 2016, but still failed. But I successfully imported the external wall with Metal building. It seems that it works well except stell-framed...I do not know why....
Then I assigned the semiheated construction to the warehouse and non-resi to the office. Unfortunately, there is another error when I ran room loads calculations. It shows that 'there is instability in room xxx'. I checked the model, and there is no errors. Have you had such problems before? May I ask for your advice? Thanks a lot!!
I'm confused with the two tables. In Table 126.96.36.199.1A option 2, the limit is fan system input power; whereas in Table G188.8.131.52, the limit given by the same equation is brake horse power, and to get the input power Pfan, we need to use Pfan = bhp / motor efficiency.
Isn't it that the two tables contradict each other?
I don't see a contradiction.
Table 184.108.40.206.1A does not limit the fan system input power, it is the BHP, which does not account for the conversion to watts and the motor efficiency. So the formula in Table 220.127.116.11.1A limits the BHP and the formula in G18.104.22.168 converts the BHP to watts.
Thanks for the clarification!
I think the confusion arises from the term "fan system input power". My initial understanding of "input power" includes motor. But apparently it's not.
I cannot find where there is any mention about "air filter loading" allowance requirements for fan power calculations. Is it acceptable to perform power calculations based in "opening day" power requirements before the filters have started loading with dirt?
Yes there is no air filter loading allowance you need to take into account.
We are using Visual DOE 4.2 software for energy modeling and we are doing one LEED NC project, the project team is planning to do the automatic sensor control window shading device, and how to take the benefit for that in my energy model (Visual DOE 4.2), please let me know
This is usually modeled as a schedule for window shades. Not sure exactly where that is found in Visual DOE.
I just got some comments back from a LEED submission.
The reviewer notes that my input summary does not match the plans. Particularly fan power.
Problem is, I already wrote and submitted a 500+ word narrative describing my modelling method. I cited T-24 procedure for excluding some fan power, and had a spreadsheet showing how the remaining power was spread among my modeled equipment.
The review made no mention of my explanation, neither confirming or refuting it.
Should I assume they read it and don’t agree? In which case the whole approach needs revisions.
Can I assume they just didn’t see it, and just resubmit it?
Submit a project team inquiry and ask the reviewer for clarification before replying.
I do need help in the energy modelling for a warehouse project. Thanks in advance!
This project consists of 200,000sf of warehouse with 5,000sf office space. The warehouse is heating only; the office uses heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. for both heating and cooling.
Now the questions came:
1. Do I need to model a cooling system in the proposed model?
2. Which baseline system shall I use? From Appendix G, system 7 should be selected. But I doubt if it is applicable for heating only space.
3. Shall I apply two baseline HVAC systems? or just use one dominant system?
1. Model a system 9 or 10 from 90.1-2010 by using the addendum that created it.
2. You subtract the area of the warehouse from the total and use the remainder in Table 3.1A. Looks like a system 3.
3. Yes two baseline systems.
In the building that I’m modeling some parts were existing prior to the project, some parts are new. Some existing parts were neither occupied nor conditioned but they are going to be occupied and conditioned after the completion of the works.
Does Table G3.1 5.f. apply for those spaces (“For existing building envelope, the baseline building design shall reflect existing conditions prior to any revisions that are part of the scope of the work being evaluated”)?
How shall those spaces be considered in the form of leedonline? Existing or new? For existing building renovations and new buildings the assigned points are different.
For previously unconditioned spaces you need to use the Table 5.5-X minimums and treat them like they were new construction in the baseline model. They do not count as new construction area however when determining the area that is % new vs % existing.
Thank you very much, Marcus.
Our project is G+3 factory building and a floor area of 1,80,000 Sq.ft
80000 Sq.ft is A/c area and remaining areas are Ventilated by fresh air fans so we take system 06-System 6—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 PFP Boxes
But the reviewer told "according to ASHRAE 90.1-2007 Table G3.1.1A, since the building is greater than 150,000 square feet, the Baseline system should be System 8: VAV with PFP boxes. Additionally, per G3.1.1, "for systems 5, 6, 7, and 8, each floor shall be modeled with a separate HVAC system." Confirm that the Baseline system was modeled correctly or revise the system type to reflect ASHRAE modeling protocol."
As of now we think the area & no floor mentioned in ASHRAE is Conditioned area & floor having conditioned area (Greater then 150000 Sq.ft)
1.Is it correct
2To model the project with system 8 is required or not for our case
3.We are confused so please tell which system we consider in simulation
4.Please advise what we tell to reviewer if the system 06 is correct
1. Unconditioned space does not count, only conditioned space.
2. Does not sound like it
3. Sounds like a system 6.
4. Explain it to them just as you have above.
Our project located in Pakistan and the client not interested in Unoccupied cooling /Heating so it not considered in proposed case energy simulation
But we consider Unoccupied cooling /Heating due to mandatory requirements (the building is G+6 so System 8 is considered as base case system.
Due to that operating hours of HVAC system is vary b/w Base case and proposed case so we get some saving in Interior fan & Space cooling load
1.Is it correct and allowed
2.If wrong means what we do either remove Unoccupied cooling /Heating in base case or consider the Unoccupied cooling /Heating in proposed case
The mandatory requirement is that the project's HVAC controls must include the required capabilities.
1. No, the baseline and proposed must have identical temperature settings and schedules.
2. It does not matter as long as the settings are identical.
Are you doing this LEED project in Pakistan ?
If an owner constructs a remote net-metered PV system as part of a power purchase agreement (PPA), can the PPA cost savings be used to increase the efficiency (cost) savings vs. the baseline model (EAc1)? (With the assumption that the baseline model would use the "normal" purchased utility electric rate.) The new building project and the off-site PV system would be constructed along similar schedules, but not part of the same project scope.
No. You don't pay a penalty if it goes the other way either. The rates must be the same in both models and the renewable energy is counted based on the virtual rate from the proposed energy model. You can use the PPA rate but you would have to do so in both models.
Thanks Marcus. But if we proceed with some portion of an on-site PV system, does the on-site portion of the PV system also need to be accounted for in the base model, or can we utilize the energy cost savings to increase the number of points achieved in this credit.
Nope. No PV in the baseline and you get to count the cost savings toward your EAc1 points.
Referencing 90.1 Table G3.1.5: I understand that the envelope for an existing building baseline model should reflect existing conditions concerning thermal properties of walls and windows. It also seems to be the consensus that you don't rotate the baseline building as you would for new construction (please confirm...). So this is the question that remains for me: Does an existing building have to follow G3.1.5c for WWR, if a particular face of the existing building exceeds 40%? Or do I follow G3.1.5f literally, including WWR?
Thanks very much for any clarification,
Correct you do not rotate an existing building.
The 40% WWR is for the entire building, not each facade. If the total is under 40% model the baseline identically.
And if the total fenestration for both the proposed building and the existing building exceeds 40%, how shall the baseline model be modeled?
That becomes a bit of a gray area. The conservative approach would be to limit the baseline to 40% so that would definitely be acceptable. Modeling it identical to the proposed is less conservative and less likely to be accepted by the reviewer.
Thanks. That answers it for me. And thanks to R2M for completing my question.
I am modeling a museum with separately controlled exhibit lighting. I am using Section 9.6 of 90.1 2007 (space by space) to calculate my baseline general lighting power densities. Section 9.2 indicates that the exhibit lighting would be excepted from the Section 9.6 interior lighting power allowanceInterior lighting power allowance is the maximum lighting power (in watts) allowed for the interior of a building. calculation. For LEED I understand this to mean that the exhibit lighting power should be considered as a process load, and should be modeled identically in the Proposed and Baseline models.
However, Section 9.6.2 does allow an increase in the lighting power allowance for exhibit lighting, rather than just excepting it. By this approach, for LEED purposes I would model the exhibit lighting as part of the general lighting energy, and increase the Baseline LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. according to Section 9.6.2.
So is exhibit lighting excepted from the interior lighting power allowance as indicated in Section 9.2, or does it simply allow an increase the the interior lighting power allowance as indicated in Section 9.6?
Use the increase LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. if it applies rather than seek to use the exemption. You basically have a choice to do either one.
Makes sense. Thanks!
We are working on a higher ed. project building connected to a campus-wide district heating/cooling and power plant. The plant consumes gas for direct steam production as well as in a CoGen turbine operation for electricity generation. We were given data for monthly electric and natural gas consumption and the corresponding steam, chilled water and electricity generation to be used to calculate the total heating and cooling plant efficiencies. Here are questions on how we should calculate the credit and penalty associated with this new project adding to the central plant’s needs:
1. How do we need to calculate the ratio for the electricity generation that the project can claim credit for? Do we need to calculate it as:
a. Ratio of the modeled building’s heating energy consumption (MMBtu/yr) to the plant’s current steam generation (MMBtu/yr) or
b. Ratio of the modeled building’s heating energy consumption (MMBtu/yr) to the current steam generation (MMBtu/yr)+ the modeled building’s heating energy consumption (MMBtu/yr).
2. A portion of the natural gas consumption in the data is used directly by the turbine for electricity generation. How should we factor this in to the efficiency and building ratio numbers? As our calculation stands, the turbine natural gas factors in to the overall natural gas consumption of the central plant, and the resulting effect is a reduction in overall plant efficiency in steam generation. We have calculated the overall steam generation efficiency as: (steam sent to building loop MMBtu)/[(turbine natural gas) + (steam boiler natural gas MMBtu)+(heat recovery steam generator)] = efficiency. It’s a simple in/out = efficiency calculation. We are wondering if this is an accurate representation of plant efficiency and the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source., or if we should be breaking out the natural gas for the turbine separately from the efficiency calculation, and perform a separate calculation using the proposed building ratio calculated in (1) to determine how much turbine natural gas to count as a “penalty” for the CHP electricity generation we are taking credit for in the proposed LEED model.
1. The formula to use is in Appendix D of the DESv2 on page 25. I think your "a" ratio is correct.
2. You do not need to separate the gas used by the turbine and the gas used by the central boilers. It is as simple as gas input vs steam output for the thermal efficiency.
In one of our project , we have CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. which fall under Case 1 as given in LEED Guide, CHP under Same Ownership..We have 2 nos of 500 KW Gas Generator which supplies exhaust heat to VAM Chiller [exhaust driven]-132 TR capacity. Cooling from VAM Chiller is 100% utilized LEED project building only. The power generation from Gas Generator is untilized by LEED Project Building and another building in same campus with connected load of 900 kW and 200KW respectively.
In this scenario. LEED Project is building has 900 KW Connected Load only with average operating Load of 750 KW only. The Same is considered in Proposed Case. And the other building connected load is not included in Energy Simulation as it is non LEED scope Building. WIth This the LEED project building CHP supplies power to other building. is it acceptable by LEED?
Can we Proceed Energy Simulation excluding the power generated for the Non LEED Building????
Thanks in Advance
Awaiting for ur reply
Samy, Marcus and others volunteer a huge amount of time on this forum. Please be patient—you may not get an answer within hours or days. If a question does not get answered, please consider simplifying it or doing more research on your own.
Also please understand that experts like Marcus are often hired as consultants on LEED projects. Many projects would benefit from hiring a dedicated energy consultant, as complicated questions come up that are beyond the scope of what a generalist can answer.
Certainly the more complex the question, the longer it takes to do the research necessary to reply. While we have most of this stuff memorized we don't have it all memorized.
I am reminded of a saying - good, fast, cheap - pick two. Since I don't compromise on at least good advice and it's free hopefully you can understand why it might not be fast.
I will try to get to this one later today.
The short answers to your questions are yes and yes.
The chilled water is considered free.
The gas input to the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. is all included in the Proposed Case. The electricity going to the LEED project is then free. The gas input used to produce the electricity going to the non-LEED project is included in the Baseline as a process load. See page 267 in the Reference Guide.
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