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 EAp2 more stringent. 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.
This prerequisite is a big one, not only because it’s required for all projects, but also because it feeds directly into EAc1: Optimize Energy Performance, where about a fifth of the total available points in LEED are at stake. Master these minimum requirements, and you can use the same compliance path as in EAp2 to earning points.
You won’t earn the prerequisite by accident, though. Although “energy efficiency” is on everyone’s lips, the mandatory and performance-based requirements for EAp2 go beyond code compliance in most places. That said, there is nothing to stop you from meeting the requirements with a reasonable amount of effort, and the environmental benefits as well as the operational cost savings are significant.
Most projects start by choosing which of the three available compliance paths to follow. We’ll look at them each in turn.
Option 1 alone gives you access to all of the points available through EAc1, and offers the most flexibility in giving you credit for innovative designs.
First, you need to meet the mandatory requirements of ASHRAE 90.1-2007 for all major components, including the envelope, HVAC, lighting, and domestic hot water. ASHRAE 90.1 has had some changes and new mandatory requirements since the 2004 version, which was referenced on previous LEED systems, so be sure to review the standard carefully.
Energy efficiency is an area where it behooves project teams to start early and work together to maximize savings. Playing catch-up later on can be costly.Second, you need to demonstrate a 10% savings (5% for existing buildings) for your designed building compared with a baseline case meeting the minimum requirements of ASHRAE 90.1 (or Title 24-2005, Part 6 for California projects). You do this by creating a computer model following rules described in Appendix G of ASHRAE 90.1.
Computer modeling offers the following key advantages:
Your building type may not have a choice—you may have to follow this path, because both Options 2 and 3 are prescriptive compliance paths that are only available to specific building types and sizes.
However, if your building type and size allow, and you don’t want to embark on the complex process of computer modeling, which also requires expert assistance from a modeler or from a member of the mechanical engineer’s team, the prescriptive compliance paths are a good way to earn the prerequisite simply by following a checklist.
Passive design strategies such as shading to reduce solar heat gain are the most cost-effective ways to improve energy performance.Note, however, that when you get to EAc1, there are a lot fewer points on the table for the prescriptive paths, and that you have to follow each prescriptive requirement. These paths also require more collaboration and focus early on in design than you might think. The design team must work together to integrate all of the prescriptive requirements, and Option 3 even requires documentation of certain design processes.
The Advanced Energy Design Guides are published by ASHRAE for office, warehouse, and retail projects less than 20,000 ft2—so if you don’t fall into one of those categories, you’re not eligible for this path.
These guides outline strategies to reduce energy use by 30% from 2001 levels, or an amount equivalent to approximately 10%–14% reduction from ASHRAE 90.1-2007. If you choose this compliance path, become familiar with the list of prescriptive requirements and commit to meeting all of them.
The Core Performance Guide path is a good option if all of the following are true:
Comply with all requirements within Sections 1 and 2 of the guide. If you choose this path, become familiar with the list of prescriptive requirements and commit to meeting them. Also note that it’s not just a list of prescriptive requirements, but a prescribed process for achieving energy efficiency goals. You must demonstrate that you considered a couple of alternate designs, for example, and that certain team meetings were held.
Energy efficiency offers a clear combination of environmental benefit and benefit to the owner through reduced operational expenses, and potentially reduced first costs, if you’re able to reduce the size and complexity of your HVAC system with a more efficient envelope.
High-tech HVAC systems, and onsite renewable energy generation are often signature components of green buildings, but consider these strategies more “icing” on the cake, rather than a place to start. Start with building orientation and passive design features first. Also look at envelope design, such as energy-efficient windows, walls and roof, before looking at HVAC and plug loads. A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective.
Projects connected to district energy systems will not be able to utilize the system efficiencies of the base plant to demonstrate compliance with the prerequisite. They can plan on benefiting from these systems under EAc1, however.
Focusing on energy efficiency and renewable energy generation can seem to add costs to a project, but there are a variety of utility-provided, as well as state, and federal incentives available to offset those premiums. (See Resources.)
Ideally if the software you are using cannot model a technology directly then seek a published workaround related to your software. If you can't find a published workaround then model it as you think it should be modeled and explain how you have modeled it in the preliminary LEED submission.
No, not if it is part of the LEED project. However, there is an exemption for existing building envelopes in Appendix G that allow you to model the existing condition in the baseline so you do not pay a penalty.
No, not for an existing building.
You must model accurately. Since you don't have enough savings in the building energy, find savings in the process. Either you will be able to demonstrate that compared to a conventional baseline the process being installed into the factory is demonstrably better than "similar newly constructed facilities," allowing you to claim some savings, or the owner needs to install some energy-saving measures into the process to get the project the rest of the way there. Either option can be difficult, but not impossible.
Account for process load reductions through the exceptional calculation method. A baseline must be established based on standard practice for the process in your location. Any claim of energy savings needs a thorough narrative explaining the baseline and the strategy for energy savings along with an explanation of how the savings were calculated.
It is common to have a 80%–90% process load in a manufacturing facility. The 25% default in LEED is based on office buildings. If you think your load is lower than 25%, it is recommended that you explain why in a short narrative. It is also recommended to briefly explain it if your load is 25% exactly, since that level commonly reveals that the process loads were not accurately represented.
The energy savings are based on the whole building energy use—building and process. LEED does not stipulate exactly where they come from.
For LEED 2009 you'll need touse 90.1-2007. There were some significant changes in 90.1-2010—too many to account for in your LEED review, and your project would also have a much harder time demonstrating the same percentage energy savings.
Yes according to LEED, although it is not recommended as a best practice, and it is usually more cost-effective to invest in energy savings in the building.
You can assume exterior lighting savings for canopies against the baseline, but not the shading effects of canopies.
If exterior lighting is present on the project site, consider it as a constant in both energy model cases.
Any conditioned area must be included in the energy model.
The Energy Star portion of the form does not apply to international projects.
Use the tables and definitions provided in 90.1 Appendix B to determine an equivalent ASHRAE climate zone.
International projects are not required to enter a Target Finder score. Target Finder is based on U.S. energy use data.
For Section 184.108.40.206c, a manual control device would be sufficient to comply with mandatory provisions.
Submitting these forms is not common; however, it can be beneficial if you are applying for any exceptions.
Use the building area method.
Although there is no formal list of approved simulation tools, there are a few requirements per G2.2.1, including the ability of the program to provide hourly simulation for 8760 hours per year, and model ten or more thermal zones, which PHPP does not meet.
The automated Trace 700 report provides less information than is requested by the Section 1.4 tables spreadsheet. The Section 1.4 tables spreadsheet must be completed.
Assign HVAC systems as per Appendix-G and Section 6 but set thermostatic setpointsSetpoints are normal operating ranges for building systems and indoor environmental quality. When the building systems are outside of their normal operating range, action is taken by the building operator or automation system. out of range so that systems never turn on.
If it is only used for backup and not for regular use such as peak shaving—no.
SHGC is not a mandatory provision so it is available for trade-off and can be higher than the baseline.
You generally wouldn't need to upload any documentation, but particularly for a non-U.S. project, it may help to provide a short narrative about what they are based on.
Discuss your project’s energy performance objectives, along with how those are shaping design decisions, with the owner. Record energy targets in the Owners Project Requirements (OPR) for the commissioning credits EAp1 and EAc3.
You won’t earn this prerequisite by accident. The energy efficiency requirements here are typically much more stringent than local codes, so plan on giving it special attention with your team, including leadership from the owner.
Consider stating goals in terms of minimum efficiency levels and specific payback periods. For example: “Our goal is to exceed a 20% reduction from ASHRAE 90.1, with all efficiency measures having a payback period of 10 years or less.”
Develop a precedent for energy targets by conducting research on similar building types and using the EPA’s Target Finder program. (See Resources.)
For Option 1 only, you will need to comply with the mandatory requirements of ASHRAE 90.1-2007, to bring your project to the minimum level of performance. The ASHRAE 90.1-2007 User’s Manual is a great resource, with illustrated examples of solutions for meeting the requirements.
ASHRAE 90.1-2007 has some additional requirements compared with 2004. Read through the standard for a complete update. The following are some samples.
The prerequisite’s energy-reduction target of 10% is not common practice and is considered beyond code compliance.
Indirect sunlight delievered through clerestories like this helps reduce lighting loads as well as cooling loads. Photo – YRG Sustainability, Project – Cooper Union, New York A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective. Start with building orientation and passive design features first when looking for energy efficiency. Also look at envelope design, such as energy-efficient windows, walls and roof, before looking at HVAC and plug loads. HVAC may also be a good place to improve performance with more efficient equipment, but first reducing loads with smaller equipment can lead to even greater operational and upfront savings. A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective.
Don’t plan on using onsite renewable energy generation (see EAc2) to make your building energy-efficient. It is almost always more cost-effective to make an efficient building, and then to add renewables like photovoltaics as the “icing” on the cake.
Some rules of thumb to reduce energy use are:
Find the best credit compliance path based on your building type and energy-efficiency targets. Use the following considerations, noting that some projects are more suited to a prescriptive approach than others.
Option 1: Whole Building Energy Simulation requires estimating the energy use of the whole building over a calendar year, using methodology established by ASHRAE 90.1-2007, Appendix G. Option 1 establishes a computer model of the building’s architectural design and all mechanical, electrical, domestic hot water, plug load, and other energy-consuming systems and devices. The model incorporates the occupancy load and a schedule representing projected usage in order to predict energy use. This compliance path does not prescribe any technology or strategy, but requires a minimum reduction in total energy cost of 10% (5% for an existing building), compared to a baseline building with the same form and design but using systems compliant with ASHRAE 90.1-2007. You can earn additional LEED points through EAc1 for cost reductions of 12% and greater (8% for existing buildings).
Option 2: Prescriptive Compliance Path: ASHRAE Advanced Energy Design Guide refers to design guides published by ASHRAE for office, school, warehouse, and retail projects. These guides outline strategies to reduce energy use by 30% from ASHRAE 90.1-2001 levels, or an amount equivalent to a 10%–14% reduction from the ASHRAE 90.1-2007 standard. 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.)
Option 3: Prescriptive Compliance Path: Advanced Buildings Core Performance Guide is another, more basic prescriptive path. It’s a good option if your project is smaller than 100,000 ft2, cannot pursue Option 2 (because there is not an ASHRAE guide for the building type), is not a healthcare facility, lab, or warehouse—or you would rather not commit to the energy modeling required for Option 1. Your project can be of any other building type (such as office or retail). To meet the prerequisite, you must comply with all requirements within Sections 1 and 2 of the guide. If you choose this path, become familiar with the list of activities and requirements and commit to meeting them. (See Resources for a link to the Core Performance Guide and the Documentation Toolkit for the checklist of prescriptive items.)
EAc1: Optimize Energy Performance uses the same structure of Options 1–3, so it makes sense to think about the credit and the prerequisite together when making your choice. In EAc1, Option 1 offers the potential for far more points than Options 2 and 3, so if you see your project as a likely candidate for earning those points, Option 1 may be best.
Hotels, multifamily residential, and unconventional commercial buildings may not be eligible for either Option 2 or Option 3, because the prescriptive guidance of these paths was not intended for them. Complex projects, unconventional building types, off-grid projects, or those with high energy-reduction goals are better off pursuing Option 1, which provides the opportunity to explore more flexible and innovative efficiency strategies and to trade off high-energy uses for lower ones.
If your project combines new construction and existing building renovation then whatever portion contains more than 50% of the floor area would determine the energy thresholds.
Options 2 and 3 are suitable for small, conventional building types that may not have as much to gain from detailed energy modeling with Option 1.
Meeting the prescriptive requirements of Options 2 and 3 is not common practice and requires a high degree of attention to detail by your project team. (See the Documentation Toolkit for the Core Performance Guide Checklist.) These paths are more straightforward than Option 1, but don’t think of them as easy.
Options 2 and 3 require additional consultant time from architects and MEP engineers over typical design commitment, which means higher upfront costs.
Option 1 references the mandatory requirements of ASHRAE 90.1-2007, which are more stringent than earlier LEED rating systems that referred to ASHRAE 90.1-2004.
Option 1 energy simulation provides monthly and annual operating energy use and cost breakdowns. You can complete multiple iterations, refining energy-efficiency strategies each time. Payback periods can be quickly computed for efficiency strategies using their additional first costs. A building’s life is assumed to be 60 years. A payback period of five years is considered a very good choice, and 10 years is typically considered reasonable. Consult the OPR for your owners’ goals while selecting your efficiency strategies.
Option 1 energy simulation often requires hiring an energy modeling consultant, adding a cost (although this ranges, it is typically on the order of $0.10–$0.50/ft2 depending on the complexity). However, these fees produce high value in terms of design and decision-making assistance, and especially for complex or larger projects can be well worth the investment.
All compliance path options may require both the architectural and engineering teams to take some time in addition to project management to review the prescriptive checklists, fill out the LEED Online credit form, and develop the compliance document.
The architect, mechanical engineer, and lighting designer need to familiarize themselves and confirm compliance with the mandatory requirements of ASHRAE 90.1-2007, sections 5–9.
Use simple computer tools like SketchUp and Green Building Studio that are now available with energy analysis plug-ins to generate a first-order estimate of building energy use within a climate context and to identify a design direction. Note that you may need to refer to different software may not be the one used to develop complete the whole building energy simulations necessary for LEED certification.
Energy modeling can inform your project team from the start of design. Early on, review site climate data—such as temperature, humidity and wind, available from most energy software—as a team. Evaluate the site context and the microclimate, noting the effects of neighboring buildings, bodies of water, and vegetation. Estimate the distribution of energy across major end uses (such as space heating and cooling, lighting, plug loads, hot water, and any additional energy uses), targeting high-energy-use areas to focus on during design.
Use a preliminary energy use breakdown like this one to identify target areas for energy savings.Perform preliminary energy modeling in advance of the schematic design phase kick-off meeting or design charrette. The energy use breakdown can help identify targets for energy savings and point toward possible alternatives.
For existing buildings, the baseline energy model can reflect the pre-renovation features like rather than a minimally ASHRAE-compliant building. This will help you achieve additional savings in comparison with the baseline.
Projects generating renewable energy onsite should use Option 1 to best demonstrate EAp2 compliance and maximize points under EAc1. Other options are possible but won’t provide as much benefit. Like any other project, model the baseline case as a system compliant with ASHRAE 90.1-2007, using grid-connected electricity, and the design case is an “as-designed” system also using grid-connected electricity. You then plug in 100% onsite renewable energy in the final energy-cost comparison table, as required by the performance rating method (PRM) or the modeling protocol of ASHRRAE 90.1 2007, Appendix G. (Refer to the sample PRM tables in the Documentation Toolkit for taking account of onsite renewable energy.
LEED divides energy-using systems into two categories:
The energy model itself will not account for any change in plug loads from the baseline case, even if your project is making a conscious effort to purchase Energy Star or other efficient equipment. Any improvement made in plug loads must be documented separately, using the exceptional calculation methodology (ECM), as described in ASHRAE 90.1-2007. These calculations determine the design case energy cost compared to the baseline case. They are included in the performance rating method (PRM) table or directly in the baseline and design case model.
Besides energy modeling, you may need to use the exceptional calculation methodology (ECM) when any of the following situations occur:
Some energy-modeling software tools have a daylight-modeling capability. Using the same model for both energy and IEQc8.1: Daylight and Views—Daylight can greatly reduce the cost of your modeling efforts.
Provide a copy of the AEDG for office, retail, or warehouse, as applicable, to each team member as everyone, including the architect, mechanical and electrical engineers, lighting designer, and commissioning agents, are responsible for ensuring compliance. These are available to download free from the ASHRAE website. (See Resources.)
Find your climate zone before attempting to meet any detailed prescriptive requirements. Climate zones vary by county, so be sure to select the right one. (See the Documentation Toolkit for a list of climate zones by county.)
Develop a checklist of all requirements, and assign responsible team members to accomplish them. Hold a meeting to walk the team through the AEDG checklist for your project’s climate zone. Clarify specific design goals and prescriptive requirements in the OPR for EAp1: Fundamental Commissioning.
Early access to the AEDG by each team member avoids last-minute changes that can have cascading, and costly, effects across many building systems.
The AEDG prescriptive requirements include:
If your project team is not comfortable following these guidelines, consider switching to Option 1, which gives you more flexibility.
Although Option 2 is generally lower cost during the design phase than energy modeling, the compliance path is top heavy—it requires additional meeting time upfront for key design members.
Provide a copy of the New Buildings Institute Advanced Buildings: Core Performance Guide to each team member. The guide is available to download free from the NBI website. (See Resources.)
The guide provides practical design assistance that can be used throughout the design process.
Walk your team through the project checklist to clarify design goals and prescriptive requirements.
The guide provides an outline for approaching an energy-efficient design, in addition to a list of prescriptive measures. The first of its three sections emphasizes process and team interaction rather than specific building systems or features. Advise the owner to read through the guide in order to understand what is required of the architect and engineers.
Section 1 in the guide focuses on best practices that benefit the project during the pre-design and schematic design stages, such as analyzing alternative designs and writing the owner’s project requirements (OPR).
Section 2 of the Core Performance Guide describes architectural, lighting, and mechanical systems to be included. Section 3 is not required for EAp2 but includes additional opportunities for energy savings that can earn EAc1 points.
The guide mandates that your team develop a minimum of three different design concepts to select from for best energy use.
Though they can be a little daunting at first glance, a majority of the guide’s requirements overlap with other LEED credits, such as EAp1: Fundamental Commissioning, IEQp1: Minimum Indoor Air Quality Performance, and IEQc6.1: Controllability of Systems—Lighting Controls.
This compliance path is top-heavy due to upfront consultant time, but it provides adequate structure to ensure that your project is in compliance with the prerequisite requirements. For some projects it may be less expensive to pursue than Option 1.
The owner should now have finalized the OPR with the support of the architect, as part of the commissioning credits EAp1 and EAc3. The goals identified here will help your team identify energy-reduction and occupant-comfort strategies.
Consider a broad range of energy-efficiency strategies and tools, including passive solar, daylighting, cooling-load reduction, and natural ventilation to reduce heating and cooling loads.
Develop the basis of design (BOD) document in conjunction with your mechanical engineer and architect for EAp1: Fundamental Commissioning, noting key design parameters to help strategize design direction as outlined in the OPR.
The OPR and BOD serve the larger purpose of documenting the owner’s vision and your team’s ideas to meet those goals. The BOD is intended to be a work-in-progress and should be updated at all key milestones in your project. Writing the document gives you an opportunity to capture the owner’s goals, whether just to meet the prerequisite or to achieve points under EAc1.
Confirm that your chosen compliance path is the most appropriate for your project, and make any changes now. Following a review with the design team and owner, ensure that everyone is on board with contracting an energy modeler for Option 1 or meeting all the prescriptive requirements under Options 2 or 3.
Sometimes teams change from Option 1 to Options 2 or 3 very late in the design phase for various reasons including not realizing the cost of energy modeling. Making that change is risky, though: the prescriptive paths are all-or-nothing—you must comply with every item, without exception. Evaluate each requirement and consult with the contractor and estimator to ensure the inclusion of all activities within project management.
To avoid costly, last-minute decisions, develop a comprehensive, component-based cost model as a decision matrix for your project. The model will help establish additional cost requirements for each energy conservation measure. It will also illustrate cost reductions from decreased equipment size, construction rendered unnecessary by energy conservation measures, and reduced architectural provisions for space and equipment access. (See the Documentation Toolkit for an example.)
Use envelope design and passive strategies to reduce the heating and cooling loads prior to detailed design of HVAC systems. Passive strategies can reduce heating and cooling loads, giving the engineer more options, including smaller or innovative systems.
Load reduction requires coordinated efforts by all design members including the architect, lighting designer, interior designer, information-technology manager, and owner.
Involving facilities staff in the design process can further inform key design decisions, helping ensure successful operation and low maintenance costs.
Encourage your design team to brainstorm design innovations and energy-reduction strategies. This provides a communication link among team members so they can make informed decisions.
More energy-efficient HVAC equipment can cost more relative to conventional equipment. However, by reducing heating and cooling loads through good passive design, the mechanical engineer can often reduce the size and cost of the system. Reduced system size can save money through:
Review case studies of similar energy-efficient buildings in the same climate to provide helpful hints for selecting energy-efficiency measures. For example, a building in a heating-dominated climate can often benefit from natural ventilation and free cooling during shoulder seasons. (See Resources for leading industry journals showcasing success stories around the country and internationally.)
The relationship between first costs and operating costs can be complex. For example, more efficient windows will be more expensive, but could reduce the size and cost of mechanical equipment. A more efficient HVAC system may be more expensive, but will reduce operating costs. Play around with variables and different strategies to get the right fit for the building and the owner’s goals as stated in the OPR.
Review and confirm compliance with the mandatory requirements of all the relevant sections of ASHRAE 90.1-2007
Trust your project’s energy modeling task to a mechanical firm with a proven track record in using models as design tools, and experience with your building type.
Contract an energy modeling team for the project. These services may be provided by the mechanical engineering firm on the design team or by an outside consultant. Software used for detailed energy use analysis and submitted for final LEED certification must be accepted by the regulatory authority with jurisdiction, and must comply with paragraph G2.2 of ASHRAE Standard 90.1-2007. Refer to Resources for a list of Department of Energy approved energy-analysis software that may be used for LEED projects.
Design team members, including the architect and mechanical engineer at a minimum, need to work together to identify a percentage improvement goal for project energy use over the ASHRAE 90.1-2007-compliant baseline model. The percentage should be at least 10% to meet the prerequisite.
Plan on initiating energy modeling during the design process, and use it to inform your design—preferably executing several iterations of the design as you improve the modeled energy performance.
Ask the modeling consultant to develop an annual energy-use breakdown—in order to pick the “fattest” targets for energy reduction. A typical energy-use breakdown required for LEED submission and ASHRAE protocol includes:
Identify critical areas in which to reduce loads. For example, in a data center, the plug loads are the largest energy load. Small changes in lighting density might bring down the energy use but represent only a small fraction of annual energy use.
Don't forget that LEED (following ASHRAE) uses energy cost and not straight energy when it compares your design to a base case. That's important because you might choose to use a system that burns natural gas instead of electricity and come out with a lower cost, even though the on-site energy usage in kBtus or kWhs is higher. Generally you have to specify the same fuel in your design case and in the base case, however, so you can't simply switch fuels to show a cost savings
Explore and analyze design alternatives for energy use analyses to compare the cost-effectiveness of your design choices. For example, do you get better overall performance from a better window or from adding a PV panel? Will demand-control ventilation outperform increased ceiling insulation?
Simple, comparative energy analyses of conceptual design forms are useful ways to utilize an energy model at this stage. Sample scenarios include varying the area of east-facing windows and looking at 35% versus 55% glazing. Each scenario can be ranked by absolute energy use to make informed decisions during the design stage.
If your project is using BIM software, the model can be plugged into the energy analysis software to provide quick, real-time results and support better decisions.
Model development should be carried out following the PRM from ASHRAE 90.1-2007, Appendix G, and the LEED 2009 Design and Construction Reference Guide, Table in EAc1. In case of a conflict between ASHRAE and LEED guidelines, follow LEED.
Projects using district energy systems have special requirements. For EAp2, the proposed building must achieve the 10% energy savings without counting the effects of the district generation system. To earn points in EAc1 you can take advantage of the district system’s efficiency, but you have to run the energy model again to claim those benefits (see EAc1 for details).
While you could run the required energy model at the end of the design development phase, simply to demonstrate your prerequisite compliance, you don’t get the most value that way in terms of effort and expense. Instead, do it early in the design phase, and run several versions as you optimize your design. Running the model also gives you an opportunity to make improvements if your project finds itself below the required 10% savings threshold.
The baseline model is the designed building with mechanical systems specified in ASHRAE 90.1-2007, Appendix G, for the specific building type, with a window-to-wall ratio at a maximum of 40%, and minimally code-compliant specifications for the envelope, lighting, and mechanical components. It can be developed as soon as preliminary drawings are completed. The baseline is compared to the design case to provide a percentage of reduction in annual energy use. To avoid any bias from orientation, you need to run the baseline model in each of the four primary directions, and the average serves as your final baseline figure.
The design-case is modeled using the schematic design, orientation, and proposed window-to-wall ratio—¬the model will return design-case annual energy costs. Earn points by demonstrating percentage reductions in annual energy costs from the design to the baseline case. EAp2 is achieved if the design case is 10% lower than the baseline in new construction (or 5% less in existing building renovations).
Provide as much project and design detail to the modeler as possible. A checklist is typically developed by the energy modeler, listing all the construction details of the walls, roof, slabs, windows, mechanical systems, equipment efficiencies, occupancy load, and schedule of operations. Any additional relevant information or design changes should be brought to the modeler’s attention as soon as possible. The more realistic the energy model is, the more accurate the energy use figure, leading to better help with your design.
Invite energy modelers to project meetings. An experienced modeler can often assist in decision-making during design meetings, even without running complete models each time.
All known plug loads must be included in the model. The baseline and design-case models assume identical plug loads. If your project is deliberately attempting to reduce plug loads, demonstrate this by following the exceptional calculation method (ECM), as described in ASHRAE 90.1-2007, G2.5. Incorporate these results in the model to determine energy savings.
For items outside the owner’s control—like lighting layout, fans and pumps—the parameters for the design and baseline models must be identical.
It can take anywhere from a few days to a few weeks to generate meaningful energy modeling results. Schedule the due dates for modeling results so that they can inform your design process.
Review the rate structure from your electrical utility. The format can inform your team of the measures likely to be most effective in reducing energy costs, especially as they vary over season, peak load, and additional charges beyond minimum energy use.
Performing a cost-benefit analysis in conjunction with energy modeling can determine payback times for all the energy strategies, helping the iterative design process.
Using energy modeling only to check compliance after the design stage wastes much of the value of the service, and thus your investment.
The architect and mechanical engineer should carefully read the applicable ASHRAE Advanced Energy Design Guide for office, warehouse, or retail projects, as applicable.
Keep the owner abreast of the design decisions dictated by the standard. Fill in the team-developed checklist, within the climate zone table’s prescribed requirements, with appropriate envelope improvements, system efficiencies, and a configuration that meets the standard requirements.
As a prescriptive path, this option relies heavily on following the requirement checklist, which is used throughout the design process to track progress. To assist design development, provide all critical team members—not limited to the architect, mechanical and electrical engineers, and lighting designer—with a checklist highlighting their appointed tasks.
The architect, mechanical engineer, and lighting designer need to discuss each requirement and its design ramifications. Hold these meetings every six to eight weeks to discuss progress and make sure all requirements are being met.
Confirm that your project team is comfortable with following all the prescribed requirements. If not, switch to Option 1: Whole Building Energy Simulation.
The LEED Online credit form does not specify how to document each prescriptive requirement because they are so different for each project; it only requires a signed confirmation by the MEP for meeting AEDG requirements. You still have to provide documentation. Submit your checklist of requirements, and supporting information for each item, through LEED Online to make your case. If your project fails to meet even one requirement, it will fail to earn the prerequisite, thus jeopardizing LEED certification.
Although energy modeling consultant costs are avoided by this option, additional staff time will be required to document and track compliance status, as compared with conventional projects.
Energy efficiency measures prescribed by the guide can be perceived as additional costs in comparison with conventional projects. However, they are easy to implement and are cost-effective pn the whole.
Become familiar with the Core Performance Guide early in the design phase to know the multiple requirements and all requisite documents.
Note that the guide demands additional time, attention, and integrated process from the design team as compared to conventional projects. It’s not just a list of prescriptive requirements, but a prescribed process for achieving energy efficiency goals. LEED Online documentation requires proof of all steps outlined in Sections 1 and 2, including three conceptual design options and meeting minutes. The project manager, architect, and mechanical engineer should read the complete Core Performance Guide carefully to know beforehand the prescriptive requirements in Sections 1 and 2.
The project manager must take responsibility for ensuring that the requirement checklist is on track.
For Section 3, the design team needs to identify three or more of the listed strategies as possible targets for the project.
Create a checklist of requirements and assign a responsible party to each item.
The Core Performance Guide requires an integrated design contributed by the architect, mechanical and electrical engineers, and lighting designer. The project manager must take responsibility for shepherding and documenting the collaborative process to demonstrate compliance.
A long documentation list can be overwhelming for your team, so create a detailed checklist with tasks delegated to individual team members, allowing each member to focus on assigned tasks. The checklist can function as a status tracking document and, finally, the deliverable for LEED Online.
The architect and engineer, and other project team members, continue to develop a high-performance building envelope with efficient mechanical and lighting systems.
Constant communication and feedback among project team members, owner, and if possible, operational staff, during design development can minimize construction as well as operational costs and keep your project on schedule.
If you change or go through value-engineering on any specifications, such as the solar-heat gain coefficient of glazing, for example, be aware of impacts on mechanical system sizing. Making changes like this might not pay off as much as it first appears.
Consider using building information modeling (BIM) tools to keep design decisions up to date and well documented for all team members.
Schedule delays can be avoided if all team members share their ideas and update documents during the design development process.
The modeler completes the energy analysis of the selected design and system and offers alternative scenarios for discussion. The modeler presents the energy cost reduction results to the team, identifying the LEED threshold achieved.
It’s helpful for the energy modeling report to include a simple payback analysis to assist the owner in making an informed decision on the operational savings of recommended features.
The architect and HVAC engineer should agree on the design, working with the cost estimator and owner.
Demonstrating reductions in non-regulated loads requires a rigorous definition of the baseline case. The loads must be totally equivalent, in terms of functionality, to the proposed design case. For example, reducing the number of computers in the building does not qualify as a legitimate reduction in non-regulated loads. However, the substitution of laptops for desktop computers, and utilization of flat-screen displays instead of CRTs for the same number of computers, may qualify as a reduction.
Residential and hospitality projects that use low-flow showers, lavatories, and kitchen sinks (contributing to WEp1) benefit from lower energy use due to reduced overall demand for hot water. However, for energy-savings calculations, these are considered process loads that must be modeled as identical in baseline and design cases, or you have the choice of demonstrating the savings with ECM for process loads.
Perform daylight calculations in conjunction with energy modeling to balance the potentially competing goals of more daylight versus higher solar-heat gain resulting in high cooling loads.
If your project is pursuing renewable energy, the energy generated is accounted for by using the PRM. These results provide information about whether the energy is contributing to EAc2: Onsite Renewable Energy.
A cost-benefit analysis can help the owner understand the return on investment of big-ticket, energy-conserving equipment that lowers operating energy bills with a quick payback.
Complete at least half of the energy modeling effort by the end of the design development stage. Help the design team to finalize strategy through intensive, early efforts in energy modeling. Once the team has a design direction, the modeler can develop a second model during the construction documents phase for final confirmation.
If pursuing ECM for non-regulated loads, calculate energy saving for each measure separately if you are, for example, installing an energy-efficient elevator instead of a typical one so that the reduction would contribute to total building energy savings. Calculate the anticipated energy use of the typical elevator in kBTUs or kWh. Using the same occupancy load, calculate the energy use of the efficient elevator. Incorporate the savings into design case energy use within the PRM. Refer to the ECM strategy for detailed calculation guidelines.
Ensure that all prescriptive requirements are incorporated into the design by the end of the design development stage.
Revisit the Advanced Energy Design Guides (AEDG) checklist to ensure that the design meets the prescriptive requirements.
The mechanical engineer, lighting consultant, and architect revisit the checklist for an update on the requirements and how they are being integrated into the design. All prescriptive requirements should be specifically incorporated into the design by the end of the design development phase.
The mechanical engineer and architect track the status of each requirement.
While the LEED Online credit form does not require detailed documentation for each Core Performance Guide requirement, it is important that each item be documented as required and reviewed by the rest of the team to confirm compliance, especially as further documentation may be requested by during review. Your design team should work with the owner to identify cost-effective strategies from Section 3 that can be pursued for the project.
Construction documents clearly detail the architectural and mechanical systems that address energy-efficiency strategies.
Confirm that specifications and the bid package integrate all equipment and activities associated with the project.
If the project goes through value engineering, refer to the OPR and BOD to ensure that no key comfort, health, productivity, daylight, or life-cycle cost concerns are sacrificed.
During the budget estimating phase, the project team may decide to remove some energy-saving strategies that have been identified as high-cost items during the value-engineering process. However, it is very important to help the project team understand that these so-called add-ons are actually integral to the building’s market value and the owner’s goals.
Removing an atrium, for example, due to high cost may provide additional saleable floor area, but may also reduce daylight penetration while increasing the lighting and conditioning loads.
Although this prerequisite is a design-phase submittal, it may make sense to submit it, along with EAc1, after construction. Your project could undergo changes during construction that might compel a new run of the energy model to obtain the latest energy-saving information. Waiting until the completion of construction ensures that the actual designed project is reflected in your energy model.
Create a final energy model based completely on construction document drawings—to confirm actual energy savings as compared to ASHRAE 90.1-2007 requirements. An energy model based on the construction documents phase will provide realistic energy-cost savings and corresponding LEED points likely to be earned.
Make sure the results fit the LEED Online credit form requirements. For example, the unmet load hours have to be less than 300 and process loads will raise a red flag if they’re not approximately 25%. If any of the results are off mark, take time to redo the model. Time spent in design saves more later on in the LEED review process.
Finalize all design decisions and confirm that you’ve met all of the prescriptive requirements. Your team must document the checklist with relevant project drawings, including wall sections, specifications, and the MEP drawing layout.
Value engineering and other factors can result in design changes that eliminate certain energy features relevant to the prerequisite. As this compliance path is prescriptive, your project cannot afford to drop even one prescribed item.
Value engineering and other factors can result in design changes that eliminate certain energy features relevant to the credit. As this compliance path is prescriptive, your project cannot afford to drop even one listed item. Although perceived as high-cost, prescriptive requirements lower energy costs during operation and provide a simple payback structure.
The architect and mechanical engineer review the shop drawings to confirm the installation of the selected systems.
The commissioning agent and the contractor conduct functional testing of all mechanical equipment in accordance with EAp1: Fundamental Commissioning and EAc3: Enhanced Commissioning.
Find your Energy Star rating with EPA’s Target Finder tool if your building type is in the database. Input your project location, size, and number of occupants, computers, and kitchen appliances. The target may be a percentage energy-use reduction compared to a code-compliant building, or “anticipated energy use” data from energy model results. Add information about your fuel use and rate, then click to “View Results.” Your Target Finder score should be documented at LEED Online.
Plan for frequent site visits by the mechanical designer and architect during construction and installation to make sure construction meets the design intent and specifications.
Emphasize team interaction and construction involvement when defining the project scope with key design team members. Contractor and designer meetings can help ensure correct construction practices and avoid high change-order costs for the owner.
Subcontractors may attempt to add a premium during the bidding process for any unusual or unknown materials or practices, so inform your construction bidders of any atypical design systems at the pre-bid meeting.
The energy modeler ensures that any final design changes have been incorporated into the updated model.
Upon finalizing of the design, the responsible party or energy modeler completes the LEED Online submittal with building design inputs and a PRM result energy summary.
Although EAp2 is a design phase submittals, it may make sense to submit it (along with EAc1) after construction. Your project could undergo changes during construction that might require a new run of the energy model. Waiting until the completion of construction ensures that your actual designed project is reflected. On the other hand, it gives you less opportunity to respond to questions that might come up during a LEED review.
Include supporting documents like equipment cut sheets, specifications and equipment schedules to demonstrate all energy efficiency measures claimed in the building.
It common for the LEED reviewers to make requests for more information. Go along with the process—it doesn’t mean that you’ve lost the credit. Provide as much information for LEED Online submittal as requested and possible.
The design team completes the LEED Online documentation, signing off on compliance with the applicable AEDG, and writing the narrative report on the design approach and key highlights.
During LEED submission, the project team needs to make an extra effort to support the prerequisite with the completed checklist and the required documents. Although the LEED rating system does not list detailed documentation, it is best practice to send in supporting documents for the prescriptive requirements from the AEDG. The supporting documents should include relevant narratives, wall sections, mechanical drawings, and calculations.
Although the LEED Online sign-off does not include a checklist of AEDG requirements, it assumes that the team member is confirming compliance with all detailed requirements of the guide.
The design team completes the LEED Online credit form, signing off on compliance with the Core Performance Guide, and writing the narrative report on the design approach and key highlights.
During LEED submission, your project team needs to make an extra effort to support the prerequisite with the completed checklist and the required documents. Although not every requirement may be mentioned in the LEED documentation, the supporting documents need to cover all requirements with narratives, wall sections, mechanical drawings, and calculations.
Many of this option’s compliance documents are common to other LEED credits or design documents, thus reducing duplicated efforts.
Develop an operations manual with input from the design team in collaboration with facility management and commissioning agent if pursuing EAc3: Enhanced Commissioning.
The benefit of designing for energy efficiency is realized only during operations and maintenance. Record energy use to confirm that your project is saving energy as anticipated. If you are not pursuing EAc5: Measurement and Verification, you can implement tracking procedures such as reviewing monthly energy bills or on-the-spot metering.
Some energy efficiency features may require special training for operations and maintenance personnel. For example, cogeneration and building automation systems require commissioning and operator training. Consider employing a trained professional to aid in creating operation manuals for specialty items.
Energy-efficiency measures with a higher first cost often provide large savings in energy use and operational energy bills. These credit requirements are directly tied to the benefits of efficient, low-cost operations.
Excerpted from LEED 2009 for New Construction and Major Renovations
To establish the minimum level of energy efficiency for the proposed building and systems to reduce environmental and economic impacts associated with excessive energy use.
Demonstrate a 10% improvement in the proposed building performance rating for new buildings, or a 5% improvement in the proposed building performance rating for major renovations to existing buildings, 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 rating according to the building performance rating method in 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.
Appendix G of Standard 90.1-2007 requires that the energy analysis done for the building performance rating method include all energy costs associated with the building project. To achieve points using 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 (for the interior, parking garage, surface parking, façade, or building grounds, etc. except as noted above), heating, ventilation and air conditioning (HVAC) (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.
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 the 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:
Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
Projects in Brazil that are certified at the “A” level under the Regulation for Energy Efficiency Labeling (PBE Edifica) program for all attributes (Envelope, Lighting, HVAC) achieve this prerequisite. The following building types cannot achieve this prerequisite using this option: Healthcare, Data Centers, Manufacturing Facilities, Warehouses, and Laboratories.
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 prerequisite. See the pilot credit library for more information.
EApc95: Alternative Energy Performance Metric ACP
Design the building envelope and systems to meet baseline requirements. 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, then 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 equivalent standard 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.
Useful web resource with information on local/regional incentives for energy-efficiency programs.
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.
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.
Research center at RPI provides access to a wide range of daylighting resources, case studies, design tools, reports, publications and more.
International association of energy modelers with various national and local chapters.
Non-profit organization aiming at design community to increase collaboration for designing energy efficient buildings.
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 website discusses the step-by-step process for energy modeling.
This online resource, supported by Natural Resources Canada, presents energy-efficient technologies, strategies for commercial buildings, and pertinent case studies.
This website is a comprehensive resource for U.S. Department of Energy information on energy efficiency and renewable energy and provides access to energy links and downloadable documents.
Information on cogenerationThe simultaneous production of electric and thermal energy in on-site, distributed energy systems; typically, waste heat from the electricity generation process is recovered and used to heat, cool, or dehumidify building space. Neither generation of electricity without use of the byproduct heat, nor waste-heat recovery from processes other than electricity generation is included in the definition of cogeneration., also called combined heat and power, is available from EPA through the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. Partnership. The CHP Partnership is a voluntary program seeking to reduce the environmental impact of power generation by promoting the use of CHP. The Partnership works closely with energy users, the CHP industry, state and local governments, and other clean energy stakeholders to facilitate the development of new projects and to promote their environmental and economic benefits.
Free download of AHSRAE energy savings guide, use for Option 2.
Research warehouse for strategies and case studies of energy efficiency in buildings.
An online window selection tool with performance characteristics.
This website lays out design process for developing an energy efficient building.
This website discusses ways to improve design for lower energy demand as they relate to the AIA 2030 challenge.
This website includes discussion of design issues, materials and assemblies, window design decisions and case studies.
This site lists multiple web-based and downloadable tools that can be used for energy analyses.
This database is maintainted by the California Energy Commission and lists resources related to energy use and efficiency.
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.
Target Finder is a goal-setting tool that informs your design team about their project’s energy performance as compared to a national database of projects compiled by the EPA.
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.
A guide for achieving energy efficiency in new commercial buildings, referenced in the LEED energy credits.
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 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 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.
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.
Energy statistics from the U.S. government.
This guide includes instructional graphics and superior lighting design solutions for varying types of buildings and spaces, from private offices to big box retail stores.
This website offers information on energy efficiency in buildings, highlighting success stories, breakthrough technology, and policy updates.
Bimonthly publication on case studies and new technologies for energy efficiency in commercial buildings.
AIA publication highlighting local and state green building incentives.
2008 guidelines and performance goals from the National Science and Technology Council.
Information about energy-efficient building practices available in EDR's Design Briefs, Design Guidelines, Case Studies, and Technology Overviews.
DOE tools for whole building analyses, including energy simulation, load calculation, renewable energy, retrofit analysis and green buildings tools.
This is a computer program that predicts the one-dimensional transfer of heat and moisture.
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.
Use this checklist of prescriptive requirements (with sample filled out) to have an at-a-glance picture of AEDG requirements for Option 2, and how your project is meeting them.
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.
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.
In your supporting documentation, include spec sheets of equipment described in the Option 1 energy model or Options 2–3 prescriptive paths.
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.
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.
Sample LEED Online forms for all rating systems and versions are available on the USGBC website.
Documentation for this credit can be part of a Design Phase submittal.
See this 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. for v4 projects - http://www.usgbc.org/content/10424
You should be able to use this guidance for LEED 2009 as well.
Thanks Marcus for the advice.
We concerned for ASHRAE 90.1-2010 appliance. It's more difficult.
Do you know design standard for Cold storage of any country in Asia area?
Two issues regarding the building area method.
1. Can the reduction of the lighting power due to occupancy sensors (according to Table G3.2) be considered only if for the baseline model I use the Space-by-Space method, i.e. can it not be used with the Building Area Method? It seems that the reviewers of a model of mine consider Table G3.2 in this way but I am not sure I have understood the rule properly.
2. If I use the Building Area Method method, can I apply the general lighting power density to all the spaces (including underground parking garage)? (somewhere I read I cannot, but I'm no more able to find it. Is that rule only for ASHRAE 90.1-2010?). I'm using v. ASHRAE 90.1-2007.
1. It can be used with the Building Area method in those spaces where such controls are installed in the Proposed case.
2. You should apply the building area method to the specific building type related to the separate and distinct spaces in a building. If there is a parking garage use the garage 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 that part of the building. The question is how 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). should you take this guidance? In my mind if the area in question is significantly greater than the norm for that building type you should use a separate building type for it. Another rule to guide this question would be what produces the most conservative result. In your case a parking garage is not necessarily the norm for an office building and modeling it all as an office would not produce a conservative result. A warehouse project is also a good example. Use office for the office portion and warehouse for the warehouse portion. I would not take this down to the room level or small spaces as then you should be starting to apply the space-by-space method.
Thank you, Marcus. I guess that if you use the space-by-space method you can avoid comments from the reviewers.
The space-by-space method also tends to produce greater energy savings in our experience.
I am doing the energy model for a project. The project total area is “153,145 sf”, 25,346 sf area of the total area is condition and the other “127,799” sf area is unconditioned, “ventilation fan and louvers” are using for unconditioned area.
Please comments on it.
1. How can I model the ventilation system in Baseline and in Proposed model?
2. HVAC Baseline system depend on only condition area or the total area of project?
1. This is modeled identically as a process load in both models. Since it does not affect the loads it is just a motor running for a certain period of time so schedule it according to how the fans are expected to run in the project when operational.
2. Conditioned area.
Thank you for your comments.
i modeled the ventilation fan as a process load in both model.
project offices area conditioned by "VRF system", and offices area modeled as per design documents and baseline as per "Table G3.1.1A" .
please clarify some more issues regarding unconditioned spaces.
1. when i modeled the unconditioned spaces with VRF system, then “unmet load hours” increased by more than 300.
2. Can I use any HVAC system type except “VRF system” identically in baseline and proposed model for unconditioned spaces?
3. If I use any HVAC system type in project unconditioned spaces, then how can I model the Baseline HVAC system,its model as per "Table G3.1.1A "or identically model same specification in both energy model.
Unconditioned spaces do not have any heating or cooling equipmentThe equipment used for cooling room air in a building for human comfort. installed so they have no loads to meet.
1. You should not model the VRF system in unconditioned spaces.
2. You should only model any fans in the unconditioned spaces identically. You should not have any heating or cooling system in an unconditioned space.
3. You don't model any HVAC system type in an unconditioned space.
My project is denim factory.It process load is 945 kw. This process load is Denim coating and BENNINGER machines.if i model this process load in unconditioned "Hall" the energy saving is reduce.
1 How to model the process load ? Can i simulate the models with reduce process load?
2 If i use the "Exponential Calculation" which standard i follow for "VFDA variable frequency drive (VFD) is a device for for controlling the speed of a motor by controlling the frequency of the electrical power supplied to it. VFDs may be used to improve the efficiency of mechanical systems as well as comfort, because they use only as much power as needed, and can be adjusted continuously." based Denim machines. ?
"VFD machines are energy efficient.
1. How you model a process load depends on the software you use. Since it is located in an unconditioned space you could possibly perform the calculations outside the modeling software assuming it will not impact other energy use.
2. To show savings for a process load you must follow the exceptional calculation method. You must develop your own baseline for comparison and provide justification that you have selected a reasonable baseline. The baseline should be based on standard industry practice in your location. So in this case if installing constant speed equipment is the norm then that can be the baseline. However you will need to provide some evidence that is the case you can't just say constant speed is the norm. Establishing a reasonable baseline is often the hardest part of an exceptional calculation so I urge you to be thorough in your justification.
1. I am using "HAP" software. Model the process load in "Electrical Equipment" tab.
2. Unfortunately in our region still no establish any industry code for process load.
3. Can i follow the NEC standards or any other?
4. When i use the "Exceptional Calculation" for process load, then process load shall model in space or only separate calculation.
1. Ok I suppose.
2. There are really no industry codes for process loads anywhere in the world.
3. Not sure.
4. Whether you model it in the space or separately will depend on if it interacts with other loads in the space. If the space is unconditioned and there are not any heating, cooling, ventilation, etc. loads that are impacted then it does not have to be modeled in the space.
We are doing the Energy Model for SCHOOL Building. The client has proposed Air cooled chiller.
Class rooms are served by individual FCU, Meeting rooms are served by split units, and Auditorium, Lobby spaces are served by 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.. Separate FAHU will be used to provide fresh air to all those areas.
In Base Case, we have considered 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. and Fan power has considered as as 0.0013 bhp/cfm (Total Fan Power = 17 kW).
In Proposed Case - We have considered FCU Fan power as 0.55 W/LPS (Total Fan Power = 7 kW)., AHU Fan power as 1.2 W/LPS (Total Fan Power = 5 kW).. FAHU Fan power as 1.6 W/LPS (Total Fan Power = 8 kW)
Total Fan power Basecase= 17 KW
Total Fan power Proposed case= 20 KW
1) In our software, not possible to model FAHU, so we have distributed the total fan power (of FAHU) 8Kw to FCU’s and AHU’s. This total KW has converted into BHP and this BHP value has used to calculate BHP/CFM. Finally BHP/CFM for FCU,AHU has been entered in the software. Is this correct or Whether we need to remove FAHU from energy model
2) Whether the BC Fan power 0.0013 bhp/cfm (from Table G220.127.116.11) should be considered only for supply air
3) Whether we can consider FAHU in base case also? (Because while considering FAHU only in PC, we are getting negative savings)
4) For what kind of fan system (like FCU,AHU,FAHU, Kitchen Exhaust and Toilet Exhaust) , table G18.104.22.168 will be used and is there any spread sheet?
Thanks for your suggestions,
1. The Proposed must be modeled as designed so the FAHU must be included. The method you propose to model the FAHU appears correct.
2. The Baseline fan power includes all of the fans (supply, return, relief and exhaust) but the allowance is calculated using only the supply airflow. You can distribute the baseline fan power anyway you like. We usually do it in proportional to the proposed systems.
3. There should be no FAHU in the baseline.
4. There is a spreadsheet in the Documentation Toolkit above that can be used for the baseline fan power calculations. G22.214.171.124 is only applied to the baseline fans that are related to the space conditioning equipment.
I have a project with district steam from central plant for space heating only. The space cooling is provided by onsite using RTUs with Dx coil. Can i use 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. V2 option 2 to evaluate DES energy performance for EAp2 and EAc1 ?
Yes. Apply the 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. to only the district heat.
do we have any area requirement for energy modeling i.e. Minimum area to opt for Option 1 Whole building energy modeling aproach for EAP2?
No there is not a minimum size requirement.
I am currently working on a project which consist of 8 buildings(3 main buildings and 5 supportive building, all are between 8000 to 60,000 sq ft), we are targeting certification level only due to site constraints to achieve more points. when we started to form strategy for EAP2 and EAC1, we came out with three options which are given below,
Strategy 1 - Whole building energy modeling for 3 main building + prescriptive approach for other buildings
Strategy 2 - prescriptive approach for all the buildings
Strategy 3 - whole building energy modeling for all the buildings.
The project registration is made after April 8, 2016 which put me in raising this questions here. I am pasting 2 links below which is kind of confusing to understand and expecting your help for the same.
this link says that, for projects getting registered after April 8, 2016, option 2 and 3 (prescriptive compliance path) is not an eligible option
the PDF in this link says that, *Please note that Option 2 & 3 currently is not an eligible compliance option for projects that registered after XX/XX/XX to meet the four point mandatory minimum.
Both the Links says, that projects registered after April 8th 2016, should show a minimum of 18% for NC and 14% for existing pursuing whole building energy simulation approach.
Please comment and clarify my understandings and doubts given below.
1. Do both the links says we cannot go for prescriptive approach for any project registered after April 8th 2016? please clarify,
2. If my understanding in the above question is correct, then i can go with Strategy 3(energy modeling for all buildings) only. Am i correct.
3. The document in the Link 2 also gives me a different understanding that, there is no requirement to show 4 point mandatory for projects pursuing option 2 or 3 as there are only a maximum of 3 point available with these options. is my understanding correct?
4. If my understanding in the 3 que is correct, i can opt for Strategy 1. where i can go with both the path(prescriptive and whole building simulation) in the project for different set of buildings. In this case, how can i report the total points achieved for the project under EAC1.
5. If Strategy 1 is not possible due to any issues in documenting EAC1. can i go with Strategy 2 (prescriptive approach for all the buildings)
Prompt reply is much appreciated.
1. You can't use Option 2 or 3 for EAp2/EAc1.
3. No. There is a 4 point minimum and since the prescriptive paths can't get there they are no longer options.
4. See 3.
One of my projects is considering using LI ID #10421 (http://www.usgbc.org/content/10421) that allows v2009 projects to use ASHRAE 90.1-2010 with an adjusted point scale. We have the v05 version of the EAp2 form in LEED Online. My conundrum is there are no Section 1.4 Tables for v4 (that I can find in the Credit Library), so are we forced into using the Minimum Energy Performance Calculator for v4? (Based on the issues with the v06 forms update, I don't really want to upgrade to the v06/v07 version of the EAp2 form if I can help it.)
Under the credit resources tab the page with the v2009 calculator it says "Note: If using ASHRAE 90.1-2010 per 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. 10421, please use the v4 Minimum Energy Performance spreadsheet in lieu of this spreadsheet."
Kathryn - Yes - I've seen that remark but as evidenced below (http://www.leeduser.com/comment/redirect/64492) there are problems with the Minimum Energy Performance Calculators. I was hoping there was another option besides using those.
I think you are stuck using the new form since it is the only one that documents the 90.1-2010 baseline. If you can find another easy to thoroughly document the modeling input and output values which includes all of the necessary information I am sure it would be accepted.
Struggling with this issue as well. We used 90-2010 for a v2009-Retail project and filled out the V4 spreadsheet and it says savings is 12%. Per LIDLow-impact development: an approach to managing rainwater runoff that emphasizes on-site natural features to protect water quality, by replicating the natural land cover hydrologic regime of watersheds, and addressing runoff close to its source. Examples include better site design principles (e.g., minimizing land disturbance, preserving vegetation, minimizing impervious cover), and design practices (e.g., rain gardens, vegetated swales and buffers, permeable pavement, rainwater harvesting, soil amendments). These are engineered practices that may require specialized design assistance. 10421, that should be 7 points, if applicable, but to get 7 points, I would have to type in 24% savings in the online form.
Is that the expectation? Seems odd, since uploaded spreadsheet would show 12% savings (albeit vs. 2010).
Matthew - That is my expectation. The v4 calculator is set up for LEED v4 projects. Hence the output will show the points only for LEED v4 projects.
For now, I plan to use the Special Circumstances area of the EAp2 form to alert the review team that we are using this LI. In addition, this is where I will reference the points we are anticipating.
Note: You can input the 12% savings into the v07 form. Since the linkages are removed from the v06+ forms, this shouldn't be a problem for EAp2 or EAc1.
However, one of my contacts at USGBC wrote: "The energy team is currently writing up some additional guidance regarding each scenario for applying the calculators. They are planning to have this guidance completed by the end of next week." I am anticipating that completion date to be June 3.
I can't speak to the details here (mechanical speak is another language to me), but do the most recently issued updates to the calculators address these issues?
In the normal case for baseline system 5-8, does a kitchen must be modeled as a separated HVAC system using system 3-4. I think the internal load of the kitchen in less than 10 btuA unit of energy consumed by or delivered to a building. A Btu is an acronym for British thermal unit and is defined as the amount of energy required to increase the temperature of 1 pound of water by 1 degree Fahrenheit, at normal atmospheric pressure. Energy consumption is expressed in Btu to allow for consumption comparisons among fuels that are measured in different units./h ft difference from base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, and materials and products installed in the project (e.g., flooring, casework, wall coverings). load and if it is, the heat is normally vent out by hood. So, the actual load is obviously less than 10 btu/h ft in the space.
So, the kitchen zone should be include in the floor system of system 5-8. Am I correct?
Based on your description it does not sound like the exception applies so the kitchen would not be modeled with a separate system. The hood is typically considered a process load and modeled identically to the proposed case hood.
If a zone has a large exhaust fan which the exhaust rate is greater than the OA intake at the 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. (the rest of OA will be transferred from other zones , make up air, or infiltration). What OA rate (the small or the large one) should we put in Table 1.4 form.
The outside air intake is the outside air. So the small one.
I´m modelling a new construction Healthcare building.
To insert the results of renewable energy generation in LEED EAp2 Template, exit 3 options:
- Automatic Cost Calculation
- Manual Cost Input
- Energy Model Includes Renewables
I have modeled renewable energy (PV + Solar thermal) directly in my energy model (EnergyPlus), but the results of generation energy are not subtracted of facility energy demanded.
So, when i choose option 1 (Automatic Cost Calculation) in LEED EAp2 Template, the renewable energy generated is subtracted from results of building energy consumption.
On the other hand, in EAc2 LEED Template, the renewable energy generation is specified and the LEED points are awarded.
As I understood, if you attempte EAp2 (EAc1) with Renewable energy included, you can´t attempte EAc2.
Is it correct?
What option i have to select in EAp2 LEED Template, related with renewable energy? To attempte EAc2 too.
That is not correct. The renewables do contribute toward EAc2 no matter what option you select in the form. If the information is not automatically transferring to the EAc2 form you can always upload a narrative and calculations explaining the situation and the appropriate points will be awarded. It sounds like the automatic cost calculation is working so I would do that.
Then, renewable energy grants points in both, EAc1 and EAc2.
Or these only can grant points in a credit?
Renewable energy contributes toward the points in EAc1 and EAc2.
Recently we submit the factory building to LEED as Individual project certification not for group certification. As per local Fire and safety compliance the Support building must be separated from main building additionally the support building have Boiler room. LAB area, Compressor rooms. The support building named as utility building and it is considered in all credits such as Site, water, Energy, material, IEQ.
Now we got a mid clarification as
" The project submission includes a Utility building which acts as a support building to the main factory building; however, since the Utility building is a separate building from the main building, additional documentation must be provided confirming that the Utility building demonstrates prerequisite compliance. Note that each building in the project must independently meet the requirements of this prerequisite. It appears that only a single energy model was provided and it is unclear whether the Utility Building demonstrates compliance with EAp2. Provide supporting documentation confirming the Utility building meets the requirements for EAp2 (specifically the minimum 10% energy cost savings threshold) as an independent building"
Now How we respond to this issue.
1.Is there any requirement to meet minimum 10% saving for all building in the space for Ex we have security office, Day-care as separate building due to Fire and safety issue
2.We submitted our project for Individual certification only why we need to show the minimum energy saving for each support buildings
3.Our Utility building have 30 % of Overall building load such as Steam Boiler, Air Compressor but these equipment's are just operated in Utility building but the Steam output from Boiler and Compressed air from compressor are used in main building only so how model our utility building
4.If we consider boiler and Air compressor in Utility building energy modelling as identically it is difficult to get minimum 10% Energy cost saving
5.the utility building have Lighting and ventilation fan loads so can we consider these only in Energy modelling(Exclude the Boiler and Air Compressor Load)
1/2, Yes. The multi-building issue is governed by the MPRs and the Campus Guide.
3/4/5. You would not need to count the energy used in that building by systems that are used in other buildings. You only need to count any direct boiler or air compressor loads used in that building.
I think you have a potentially good case to not have to separate the utility building if it does not include any other space types such as an office, breakroom, etc. If it basically houses equipment and not people you may be able to argue that it would not have to be separately modeled. You could try making that case to the reviewer in a question 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). before submitting for the final review. I do not think you could make that case for the occupied separate buildings.
We have a new construction office building project in which a data center/computer room occupies about 10% of the area, but probably 95% of the load/energy. Due to cost and client request, we would like to draw the LEED project boundary around just the office portion of the building, excluding the data center from LEED certification and associated calculations. Is this allowable for LEED NC? If not, can the data center be modeled with a separate baseline for energy savings?
I would suggest that you not seek exceptions and exclusions but rather do something to reduce the data center energy use. There is specific guidance for LEED projects on this energy use - http://www.usgbc.org/resources/minimum-energy-performance-data-center-ca...
Ultimately this is not really an energy credit question. It is governed by the LEED Minimum Program Requirements. More information at
Thanks Marcus. The problem is that the design was done a long time ago before there was any guidance on data centers, so it was assumed to be an exempt occupancy. Is there any chance that an exception would be made since the data center guidance and calculator didn't exist at the time of design?
Not a good assumption and one that should have been questioned "a long time ago". I don't think that would be an acceptable basis for an exemption.
High process load project have always had an opportunity to show savings through an exceptional calculation and that method was open to you at the time. Maybe the design does have some energy saving features relative to the calculator baseline so you should at least check it out.
If you still need to exclude it your best bet will probably be through the MPRs when defining the LEED project boundary.
I have a project with two different proposed window types - metal framed storefront on the first floor retail level, and punched fiberglass windows on the eight office floors above. I've heard of two different approaches for the baseline window 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.: the first is to match the framing type in the baseline and proposed and the second is to just pick one U-Value and use that for all baseline windows. So using the first method with Table 5.5-4 (Portland, OR), the baseline storefront windows would be U-0.5 and the punched fiberglass windows would be U-0.40. Using the second method, all the baseline windows could be U-0.55 (Metal framing all other).
Whereas Appendix G is clear that all walls need to be modeled as steel-framed, it does not have a similar requirement for windows, leaving it up to interpretation. The Multifamily Midrise modeling guidelines states that nonmetal U-Value has to be used for wood frames, but for all other frame types the baseline uses Metal framing (all other).
Anyone have any input on this? Thanks.
Model each window type in in the baseline based on the proposed window types. In your example model the 1st floor U0.5 and the upper floors U0.4.
I looked for 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 of this and couldn't find one. It doesn't really seem fair, as the owner is paying extra for the upgraded fiberglass windows, but the baseline is also shifting, leading to less of a benefit for the upgrade. This sliding baseline seems more like something that would apply to code compliance, similar to how the 90.1 Chapter 11 baseline systems more closely match the proposed system (ie WSHP). In a code compliance baseline model maybe you would use 0.4, but it doesn't make sense for a LEED baseline.
Why would there be a single construction type for walls (steel-framed) in Appendix G, but not for windows?
I agree it is not consistent with other envelop parameters in the manner you describe. Your question is one for the 90.1 Appendix G committee. The way I described it is the way LEED interprets the requirements. Since Appendix G does not define the frame type the 5.5-X tables do.
In my experience if you are upgrading to fiberglass frames from metal frames the cost is neutral or even cheaper.
G3.1.1, Exception "d" requires laboratory spaces with a minimum of 5000 cfm of exhaust to use a baseline system type 5 or 7 that reduce the exhaust and makeup air volume to 50% of design values during unoccupied periods. My interpretation is that the baseline laboratory spaces should be modeled as two-position (a constant occupied airflow and a constant unoccupied airflow equal to 50% of the occupied airflow). Does anyone disagree with this approach and think the lab spaces need to be modeled in the baseline as full 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.?
Sounds right to me.
The standard states that the pump power must be 22 W/gpm.
If the project has two chillers and primary secondary circuits, whereby there is on pump per chiller in the primary circuits and 5 pumps in the secondary.
The question is: the 22 W/gpm are covering which power as per the above description?
The similar question is valid also for G126.96.36.199 and G188.8.131.52.
All opinions on the matter are highly appreciated.
The number of chillers and pumping in the proposed case has nothing to do with the baseline.
There is an ASHRAE interpretation - ASHRAE/IES IC 90.1-2007-14 - which indicates that the Baseline pump power of 22 W/gpm from Section G184.108.40.206 is inclusive of all baseline chilled water pumps. This ruling is confirmed by 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. 10299.
For G220.127.116.11 and G18.104.22.168 it is a moot point as there are only primary pumps for towers and boilers.
Shall we use LEED 2009 BD+C if the new building has 35% of energy process ? The main function is mechanical kneading without cooking process and warehouse. there are few office areas inside.
We know the new LEED 4 BD+C warehouses, but we think is too restrictive for our client.
If you prefer LEED v. 2009, you can choose it.
Consider this guide for the choice of the rating system:
Consider that for the energy performance LEED v. 2009 has a new minimum limit:
The amount of process energy in the project should not be a determining factor in the selection of which system to use. If it is only 35% then you should be able to get enough savings with either one. If you can't then look at reducing the process energy use as an exceptional calculation.
In the project we are modeling the cooling plant which serves the production area and the buildings' HVAC systems is one and the same. Probably the designers' solution is such because the cold water temperature parameters are identical for the whole building. The chillers are with refrigerant ammonia. The following questions are open at the moment and we'd highly appreciate some assistance for their resolution.
1. Does the 90.1-2007 standard regulate ammonia refrigerant water cooled chillers?
2. The cooling circuit between chillers and the served cooling coils includes intermediate heat exchanger whereas the circuit between chillers and the heat exchanger are water/glycol mixture. The evaporator's outlet temperature is -2 oC (28.4 oF). Are chillers operating with these parameters considered as regulated by the standard and if not what parameters for the Baseline chillers are to be applied? The project belongs to System 7.
2. Having in mind that the production (and all of the systems assigned to it) are to be considered as process load and are to be identical to Proposed and Baseline models, should the cooling plant be split into two sections - one for the buildings' HVAC systems and the other for the production needs.
3. Assume we split the cooling plant. Regarding the chiller part assigned to the production, the question is: In case there is a better efficiency chiller than the project one and it is readily available on the market, could we apply an exceptional calculation for evaluating the savings resulted from the better efficiency chiller?
1. Hard to say for sure. It depends on what type of chiller they are. Are these low temperature chillers? If so see the note under table 6.8.1C and Section 22.214.171.124.
2. See 126.96.36.199.
2. Yes you will need to separate the energy use of the chillers into space conditioning and process loads.
3. Yes. You do an exceptional calculation when claiming process load savings.
Thanks for the reply. It appears that these chillers are not covered by the standard as per 188.8.131.52. - they are low temperature, not very low but enough.
The question then is: How to model the Baseline cooling plant in terms of chillers - should the chillers and the chillers' circuits be identical to Proposed?Baseline HVAC system will be System 7.
The Baseline chillers are still according to Table G184.108.40.206. Where you run into a potential issue is with the process load. That aspect of the models must be modeled identically. If the chillers are more efficient than the baseline you will need to do an exceptional calculation.
Thnaks a lot for the reply.
I assume that the same approach should be applied to the heating plant - meaning to split the load between Manufascturing and HVAC systems.
Yep, same thing.
Our project owner would like to register a Data Center under LEED NC V2009.
May I know, do anyone know how to simulate the data center? because Appendix G is more into commercial building simulation, whereby data center is more equipment driven on it's process load.
The modeling protocol for a data center is spelled out in the Reference Guide. There is also a calculator you can use to help with the process load - http://www.usgbc.org/resources/minimum-energy-performance-data-center-ca...
Is there specially I have to concern when I define the fenestration's properties for jalousie-style glass in energy modeling?
Thanks in advance
This window type will have a much greater level of infiltration.
But you can model the infiltration in the same way in the proposed model and in the baseline model, right?
I think that in the future the air leakage should be considered in more detail by the standards and by the energy modelers, although it isn't easy.
I think that is correct.
Apr 20 2016
CCHP System modeling
Project Location: Japan
My project is provided by CCHP system which owned by third party, the CCHP has two gas generators, one heat recovered gas absorption chiller, two normal chillers and two boilers.
1)chilled water loop: absorption chiller + normal chillers, 100% chilled water is supplied to our Project A,
2)Hot water loop: absorption chiller ＋boilers ; 100% hot water is supplied to our Project A;
3)Recovered Heat from generators: about 53% is used for operating absorption chiller , other 47% is supply for another building B;
4)Electricity: electricity will be supplied to four buildings, included building A , B and C, D
My question is : 1) shall we follow Appendix C and D in 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. methodology since 100% chilled water and hot water is provided to our project ?
2) We use gas absorption chiller in the modelling since it has chilled water and hot water, but we found we can't use recovered heat from generator by directly connect to genertor since gas absorption chiller only has one hot water loop, so we abstracted recovered heat energy from gas consumption, is it accpetable?
If you are following Option 2 then yes you use Appendix C and D.
It sounds acceptable as long as your calculations account for the combustion efficiency and any other factors in the determination of the recovered heat contribution.
I am modeling campus building under major renovation. But since that building was built in 1968, no envelope data available (no spec. no BODBasis of design (BOD) includes design information necessary to accomplish the owner's project requirements, including system descriptions, indoor environmental quality criteria, design assumptions, and references to applicable codes, standards, regulations, and guidelines.) about the 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. or SHGCSolar heat gain coefficient (SHGC): The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. for the wall, roof or window. In this case, can I use the Table 5.5 in ASHREA 90.1 for the baseline's envelope data instead?I would really appreciate it if you give me advice.
No you can't use the Table 5.5X values.
You must either model the existing condition or use the Tables at the end of Appendix A in 90.1. For the wall and roof construction there should be a way to determine the construction type and whether there is existing insulation. You may have to actually visit the building and do some forensics. For the windows it is probably best to use Table A8.2.
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