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 22.214.171.124c, 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 performanceBaseline building performance is the annual energy cost for a building design, used as a baseline for comparison with above-standard design. rating.
Calculate the baseline building performance 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.
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.
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 DES 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.
The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 EA credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.
Version 4 forms (newest):
Version 3 forms:
These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictsions for these forms; for more information, visit LEED Online and click "Sample Forms Download."
Documentation for this credit can be part of a Design Phase submittal.
It all depends on how you are pursuing LEED Certification. Typically if dividing up the campus and pursuing projects individually the rule to follow is all the energy use within the project boundary.
Thanks for your reply, Marcus.
We are going for the Campus Program, most of the buildings will pursue an individual Certification and maybe some of them a Group Certification (it is still in a schematic phase) within the Mastersite.
If a certain system is within the project boundary of Building A, but will be serving Building A, B, and C (each with its own Certification) does the energy consumption get divided between the 3 buildings (each with its respective use)?
It is hard to say without knowing the specifics.
The water treatment plant would only need to be accounted for if it is within one of the project boundaries. Since it is a process it would be modeled identically and could possibly be divided among the projects or included in just one depending on the boundaries.
I overlooked the demand control requirement for the baseline system in the energy model, and have been directed by the reviewer to install it in 3 rooms based on calculation numbers, which makes sense. The proposed system does not include DCV, it hasn't been modeled, and hasn't been required by the reviewer.
The problem is that when I include the DCV into 2 of the systems that require this, the ventilation rate increase dramatically. One system goes from 34% outside air to 63% outside air requirement. The other system goes from 33% outside air to 100% outside air. The third system is part of the first floor System 5, and has been broken out to be it's own System 3 (per ASHRAE 90.1-2007 G3.1.1(b)), and the ventilation required matches the proposed exactly. The two systems with the increase in OA are a Gym and Auxiliary Gym, so separate system 3 was created in conjunction with the baseline required system 5 as described in G3.1.1(b).
My question is: is it common to include demand control ventilation into the system energy model and have such a drastic increase in ventilation air requirement? I am using Trane TRACE, so I don't know if this is a failure of the calculations, failure of the inputs, or if this difference is common. For general knowledge, the OA required to the spaces required are set to the same values and not set to be calculated, yet that seems to be what TRACE is doing.
I've always been under the impression that the ventilation between baseline and proposed should be the same, but this change has resulted in the baseline have a total building increase of 22.3% more OA then the proposed system, and the difference in the cost efficiency is about 9%.
The short answer is the Trace 700 DCV doesn't work well with Energy Simulations. It works great as a Load calc/design tool and determining compliance with ASHRAE 62.1, but too many variables cause it not to work so well for a simulation.
The long answer and more accurate answer to your question would take longer to explain, I'd suggest calling Trace Support and they will walk you through easiest fix or workaround.
Sounds like you may be having the software calculate the OA. With DCV in the Baseline the OA should be user entered and not calculated. The Baseline OA should be identical to the Proposed design OA. Be careful to double check how you are controlling the DCV within the model. Depending on how it is controlled it could override the manual entry and calculate the OA based on the critical zone. You might want to call Trace to get some specific guidance.
Make sure to provide justification for the use of G3.1.1 Exception (b).
Thanks for the comments, I was hoping it would be simpler than this. Calling the support was next on my list.
Two buildings (“building A” and “building B”) are on adjacent sites. The project team wants to achieve two different LEED NC certifications. The buildings are heated by the same geothermal heat pumps, which are in building A. The heat pumps are 4. One produces hot water throughout the year (it's necessary to heat the domestic hot water), while the other ones produce heated water during the winter season and cooled water during the summer season. The document “Treatment of District or Campus Thermal Energy in LEED” states that “when the building housing the thermal energy plant is itself seeking LEED certification (…) Performance method: The district energy equipment shall be modeled as upstream equipment”. I would like to use option 2 “Aggregate Building / DES Scenario”.
1. Table 4 of the document “Treatment of District or Campus Thermal Energy in LEED” states that for the proposed model a “Virtual on-site hot water or steam boiler representing upstream DH system” shall be considered. At least for building A, wouldn't modeling the geothermal heat pumps explicitly be more accurate? Consider that the effective performance of heat pumps depends on the real conditions in which they work and also during the winter season the efficiency (COP) is higher than 1.
2. As for the baseline model, I don’t know if I understand correctly the Table 4 of the document “Treatment of District or Campus Thermal Energy in LEED”. I would follow the normal procedure: the conditioned floor area is 2882 m2, the conditioned floors are three, the heat is provided by electricity (heat pumps), therefore I would model System 6 - Packaged VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with PFP boxes.
Any advice, please?
1. You would model a virtual well field (central plant) for each building. You would use the actual efficiency of the system as the efficiency for the system since there is no default value.
2. The baseline system is according to Table G3.1.1A.
Thank you. As for point 1., the real plant is composed by 42 boreholes and 4 reversible heat pumps. The heat pumps are connected in parallel. I'm going to model the two buildings separately because the projects have been registered separately. I think that I should consider the fact that for a single building the available heating/cooling rate is not the total heating/cooling rate of the plant (because at the same time also the other building needs energy). Moreover, the water temperature that comes back into the heat pumps and the part load ratio are influenced by the conditions in both buildings.
In the two virtual models, shall I consider only a part of the boreholes and only a part of the heat pumps?
The buildings have similar envelopes and they are both occupied by offices. Could I divide the “virtual boreholes” and the “virtual heat pumps” according to the envelope surfaces?
Hi Francesco, thankfully I've not had to do this myself yet, but from what I understand, you'll need to run simulations where both "buildings" (in energyplus/designbuilder these will all fall under the same building object) are connected to the plants. You then post process the total energy consumed by the shared plant and appropriate it to each building correctly. It's a damn headache...but I think it's the accepted way.
Since you can model everything working together, you could setup outputs at specific node points measuring the energy flow to each building. That might simplify things.
Hello Jean, of course a model where both buildings are connected with the heat pumps is the most accurate way to model the real physical behaviour. Actually, if I create such a model, I will be tempted to use that model also for the official review. Would it be acceptable for the reviewers although the buildings are not part of the same project (they are registered separately)? As for the heating and cooling requirements, I could divide the electrical energy between the two buildings proportionally to the heating/cooling that the buildings need. Thank you.
I think either the "virtual" well field approach or what Jean suggests would both be accepted by the reviewer. In either case be sure to include a thorough narrative explanation and the calculations associated with any post-processing. I would proportion the virtual filed based on the capacity of the units within each building. So if building A is 50 tons and building B is 40 tons proportion the field accordingly. I don't think you should proportion the field based on envelope load alone since that is only a portion of the total load.
All the heat pumps are in building A. Building B is connected with the heat pumps through pipes. I think that I'll proportion the field according to the total nominal power of heated floors and water convectors of the two buildings, or I'll follow the Jean's advice. Thanks!
I am having one difficulty in filling the form of EAp2. The “Total Energy Use” of the proposed design is dividing the sum of the values per 100, resulting in an error message and a "N" result in compliance check. In this case, and considering that EA credit 2 also depends in this pre-requisite, how should we submit this form in leed online?
Thank you in advance!
For a variety of reasons these forms often indicate a "N" for compliance. Fill out the form as best you can and submit it. If you can figure out an error then write a narrative pointing it out to the reviewer. The "N" will not affect your submission.
I need to know if anyone did experience that before. My process loads exceeds the 25% though; on the scorecard EAp2 the process load compliance is (N), I tried refreshing the form, re-entering the values, and clicked "check compliance" at the end of the form but still the same issue.
I need to know if this can be like a bug in the form itself or I'am mis-understanding something?
What version of the form are you using? There are two places that you can check to see if you are over 25%. The second is within the energy cost table toward the end.
I would not worry about this as it is likely a glitch in the form. If you are over the 25% provide a narrative explaining that you are and that the form does not appear to be working correctly.
As part of the Alternative Compliance Path, "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."
Anybody knows of an approved European standard?
Nope, I am not aware of any approved alternative.
We are looking at an existing 300,000 s.f. hotel highrise in a downtown location that is currently on a citywide district steam utility. There are extensive interior architectural changes and a moderate amount of mechanical, so we are pursuing LEED NC. The thought is to install gas-fired boilers within the building, removing it from the (greatly inefficient) district system. Can this be modeled as an Option 1 DES in the baseline case, and an appropriate gas-fired boiler plant in the proposed? "Treatment of District or Campus Thermal Energy in LEED V2" does not seem to address this situation.
You model HVAC equipment against a code compliant baseline, not existing conditions. So, if your proposed case is not DES, neither is your baseline. You can't take credit for disconnecting from the DES any more than you can take credit for replacing an old piece of equipment.
For what it's worth, you'd be penalized for the inefficient district system if you stayed connected to it. So you got that going for you, which is nice.
We are working on an industrial facility project, in this case the process loads represent a 60-70% aprox.
The intent of the client is to bring equipment from another plant and re-use it in the new project, therefore we need to know if there is an exeption for the re-used equipment.
This equipment they will re-use in this new facility is old, and we can´t demonstrate improvement in process loads. If we have to model the baseline and the project case with the same characteristics we will not be able to achieve this prerequisite.
Thank you in advance.
You must model the old equipment identically. There is no applicable exception.
I need to know if both; Basecase and Proposed case should be identical meaning that both should be oversized with the same ratio? or the proposed case must be as designed without any oversizing ratio?
The only reason you should need to oversize the proposed is if you need to do so to reduce unmet hours in the proposed case.
The Proposed is as designed. Baseline 115% cooling and 125% heating when auto-sizing the system capacities.
I have wall assemblies with no cavity insulation but 3-4 inches rigid insulation outboard of structural sheathing. The wall is finished by a composite metal panel. Do I have to consider ASHRAE appendix A for such an assembly? I would imagine the thermal bridging effects of the studs would be very minimal in such an assembly.
You should always use Appendix A to determine the assembly performance.
When residual process heat is used to heat the building, which is more efficient than discarding it, can this be rewarded in EAP2/c1?
Whether you can claim savings depends on the Baseline definition. If heat recovery is standard practice relative to the process then no, you can't claim savings. If is is not standard practice then you can.
Iam working on an international project and I can find my country and all countries in the list of Energy Star target finder, so I wonder why projects outside the US can't fill the target finder part?
I also need to know where to find the % of "CO2Carbon dioxide-eq emissions reduction" (that is required in the LEEDonline form) in the Target finder results?
If you select your country and go all the way through to the results do you get results? If you don't get results then you won't have a Target Finder score to report. There were relatively recent changes to TF and Portfolio Manager. One of them I noticed was that in TF there are many more project types than there used to be but when you select one not covered by TF you get a message indicating that it can't give you a score. So make sure to run it all the way through and do not rely on a list in the entry page.
The CO2Carbon dioxide reduction % should be in the results.
I have a couple of questions regarding the space types listed in ASHRAE 90.1 Table 9.6.1 (Space-by-Space Method):
1) For underground car parking, the closest space type is the "Parking Garage - Garage Area" which appears to have a very low LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. allowance (2 W/m2). Isn't it a bit strange to have a 2 W/m2 in the Space by Space method while having 3 W/m2 in the Building Area Method? I thought the Space-by-Space always has higher LPD allowances
2) For seating areas in restaurants inside a Shopping Mall, do we choose "Dining Area" or "Dining Area for Family dining" (there's a big difference in the allowed LPD)?
3) The Mall has a big Entertainment zone (mainly an area for kids to play videogames). There doesn't seem to be a matching space type in Table 9.6.1. Does this mean that these are not regulated and that we have to model the baseline as per the proposed lighting?
4) Are "Motion Picture Theaters" equivalent to "Movie theaters" or "Cinemas"?
Many thanks in advance!
1. Usually but I guess not in that case. Not sure why.
2. Since there is such a big difference I would use dining in general. If you use family dinging be prepared to defend it.
3. You are entitled to select the closest use to the use in question. You do not have to model something not listed identically.
I have a suspended ceiling with a 60 cm air gap between the panels and the reinforced concrete slab where all the electro-mechanical lies, but it doesn't act as plenum zone since that all return, supply, and exhaust are ducted.
Now this zone where all electro-mechanical lies is an unconditioned zone with assumed temperature of 80F. As for the basecase simulation, I've set the concrete floor assembly U-valueU-value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The greater the U-value, the less efficient the building element is as an insulator. The inverse of (1 divided by) the U-value is the R-value. as per ASHRAE 90.1, but what about the Basecase for the gypsum-board separating conditioned zones from this false ceiling zone? can I use gypsum U-value from the eQuest library?, or should I model it same as developed case (actual design) where a 5 cm layer of insulation is placed over these panels? and in that case I won't gain any credit from this insulation layer.
Another question is that these zones are covered by veiling glass with insulation layer on all facades, so in basecase; should it have the same U-value as exterior wall since that it is opaque (veiled) glass area?
Your assumption that this is an unconditioned zone is not correct. This is part of the conditioned space. Even an insulated drop ceiling is considered to have no insulating value within 90.1. Take away your operative assumption and I assume that the remaining questions become moot.
Sounds like you are referring to what we call spandrel panels. If they are opaque then they are considered walls, so yes.
Can exterior lighting be part of the 25% process load requirement by Ashrae 90.1-2007 when it comes to energy modeling?
Exterior lighting is regulated by 90.1 and is not process.
Also keep in mind that there is no 25% process load requirement. Model the process loads as accurately as you can. If you are above 25% do nothing. If below provide an explanation indicating why you are below 25%.
I have a relatively large data center (200kw connected load) in a relatively larger building (250k sf) so that the data center is not the major program space, but is a relatively large minority of the energy use. I cannot find any guidance online or in the LEED 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's regarding how to treat a data center for LEED v3.
However, I found this in LEED v4 reference guide regarding data centers:
"The guidance in this section is geared toward dedicated data centers and is not applicable to server closets or other small computer rooms. Mixed-use data centers, in which the data center takes up only a portion of the building space, may use this information as the basis of an exceptional calculation method.
The power requirements and energy use of the IT equipment in a data center typically dwarf the energy use of the cooling system and must be considered for optimizing energy use. The energy consumption of a data center’s cooling system typically ranges from 15% to 25% of its total energy use, whereas in other commercial buildings, the HVAC
energy consumption approaches 50% of the total energy consumption.... and so on.
Anyways, what are the opinions here of how to treat a data center in LEED v3?
My opinion is I should be able to use LEED v4 guidelines to show an exceptional calculation for my LEED v3 project.
And if this is already covered somewhere else, please provide the link, thanks
You can use this calculator for v3 projects - http://www.usgbc.org/resources/minimum-energy-performance-data-center-ca...
Marcus, thanks, that probably saved me a lot of internet searching time.
The SS seems clear on the issue of electrical and IT energy savings, but it never mentions HVAC savings based on system type. Step 6 implies that the only HVAC savings would be from just the reduced cooling load if you include the reduced electrical load in the model (all of that is easily understood and modeled). However, we also were interested what we could claim for HVAC system type savings, would you know if there is another guideline for that or what is considered a baseline system or equipment efficiency for cooling of a data center?
As far as I know the baseline is still defined by 90.1. 90.1-2010 I think added some additional provisions regarding data centers so you could see if any of that was in an addendum you could apply.
In some cases, such as Hospital operating rooms and Ice Rinks, you have to maintain indoor air dewpoint temperaturs lower than 44 F. To accomplish this, you typically have to use either a desiccant dehumidifier or a low-temp, glycol chiller, neither of which have a very high COP. However, Appendix G seems to only allow for the use of a 6.1 COP chiller supplying 44 F water to provide all cooling and dehumidification in the Baseline. Not only is it this physically impossible for the Baseline chiller to do, but if you allow the energy model to disregard the laws of physics, this tends to create a larger disadvantage for the Proposed design to overcome. So is there a more equitable way to have the Baseline provide dehumidification when the Proposed design must use something other than a traditional chiller?
Check to see if any of the exceptions under G3.1.1 apply. Other quick thought would be to treat this as process perhaps?
We received the following comment from USGBC: "...The project uses natural ventilation for some bedrooms in the Proposed design and exhaust fans to induce ventilation air into the dwelling units. Verify that both models include ventilation air as required and ensure that any unconditioned ventilation air supplied to the spaces is included in the Proposed model. Describe how the ventilation systems are modeled in both cases...". The building has heat pumps with operable windows to provide outside air. Previously, we had modeled the windows shut in both cases, but it seems we would need to model this ventilation air in both cases. How would this be modeled in the Baseline, as mechanical ventilation or as natural ventilation? And what would be the best way to model the ventilation through windows in eQuest?
Classic case of a LEED reviewer inventing new requirements. ASHRAE 62.1-2007 requires the windows be operable, it does not require that they be open. Your energy model does not need to include ventilation through operable windows. Push back on the reviewer, ask for a clarification. We have successfully fought this interpretation recently.
Was this the case when you did not have any other ventilation in a space, just natural? I assume if you only have natural ventialtion in a space, that should be modelled somehow.
If you have an exhaust, set the makeup flow through the windows equal to the exhaust. This volume flow rate is then your minimum ODA requirement and is set equal in both baseline and designcase models. Due to your exhaust, you actually have no natural ventilation...it's mechanical.
Let's not confuse "natural ventilation" with passive cooling. You meet the requirements of 62.1-2007 with operable windows. Appendix G only says that the ventilation rates should be identical between baseline and proposed. Model what you think will actually happen - if you think the windows will be closed all winter there is no requirement that you size your systems or model the building as though the windows will be open.
I aggree. The requirements of 62.1 are met and we're not talking cooling. So we make sure the fresh air rates are equal for baseline and design. However, I will stick one point: you can't make the fresh air rates null. This would reduce the total energy consumption. Then if you save only a little in another area such as lighting, it makes a bigger percentge savings. That's why we don't ignore process loads. So to avoid gaming, I would make sure to include justified ventilation rates.
If you have no mechanical fresh air delivery system in the building and a bathroom or kitchen exhaust fan, the makeup air comes from outside, whether indirectly from adjacent spaces or through cracks or through windows. Energy wise this ODA is heated to temperature and consumes energy. Maybe not all in that zone, but you can account for it in the zone.
If I were a reviewer, this would be the minimum ODA I would expect to be accounted for... There are even better tools for the job: there are plenty of simulation tools dating back to BLAST or normed infiltration calculations, which are based on regressions from building data sets based on the additional energy consumption from envelope infiltration and window and door usage. ASHRAE doesn't say how you must take account of these "infiltration" effects, but it does say that you must include for them.
98% of the time what we see is a corridor ventilation system that balances the toilet exhausts. The designers have no actual intention of using the windows for ventilation - they are just there to meet code. I'm not saying this is a good design, but it meets all the existing code requirements, and to arbitrarily add additional ventilation would move the model further from reality. We'd model the corridor system as the only source of outdoor air. Of course we'd also include a reasonable number for infiltration. What we would NOT do is to set the infiltration equal to the 62.1 ventilation rate, which is what the reviewer is asking for.
Two quick notes - (1)ASHRAE 62.1-2010 fixes this problems - openings must be open during occupancy. So move up to v4.
(2) we have a client who has run blower door tests on some larger commercial (non-residential) buildings. The tests are consistently showing that even well constructed buildings have more infiltration than what us modelers generally use. We've found the same to be true when we've calibrated models on existing buildings. So us modelers are undercounting infiltration everywhere, not just on residential buildings with operable windows.
100% Agree. If the floor is mechanically fresh air supplied, this should per design be where the fresh air comes from for makeup. Infiltration is then to be assessed on its own then. Perhaps this was not clear to the reviewer and that is why they are asking for a description.
You said you have successfully fought the interpretation about including the natural ventilation rates in the model.
We are getting the same comment from the USGBC. The corridors In hour building are unconditioned because are exposed to outdoor.
Can you share how did you answer this comment?
If I have to include natural ventilation to the model. Should I do it as infiltration? Should I follow the minimum rates shown in Table 6-1 (ASHRAE 62.1) even if mechanical ventilation is not applicable?
Section 6 of Standard 62.1 applies only to mechanical ventilation systems. A natural ventilated system should NEVER follow or meet the values in those tables. If it does, it is badly designed. In fact, I would compare a good naturally ventilated building to a demand controlled ventilation. It is good practice to include (natural) ventilation rates to reflect the natural ventilation that you have. It is not prescribed how to do this. INFILTRATION is not ventilation. It is regulated in ASHRAE 90.1 2010, so you could look there for guidance.
You should also note that the ventilation rates of both models must be equal (outdoor air minimums). This means that as soon as they are not, you are taking credit and that means an exceptional calculation which for LEED means proving sufficient comfort levels. Ventilation is not to be confused with cooling.
As a side note, I'm working on a paper that takes the adaptive comfort driven window opening algorithm (Humphreys window opening behavioural algorithm in ESP-r, P. Tuohy, H.B. Rijal, et al) to the next level. If it ever gets published I'll post a link on the forum.
Christopher, Jean, thank you for your suggestions. We requested clarification from GBCI and clarified to them that we weren't claiming any savings for natural ventilation. The review team accepted our strategy of modeling closed windows on both cases.
Did you submitted 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? or you just addressed the GBCI comment with your explanation?
No 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 just went to GBCI contact page and their response was that "the clarification provided in this inquiry indicates that the ventilation air is modeled identically in the Baseline and Proposed case. Provided no savings are claimed for the natural ventilation strategy used for these spaces, the information provided is sufficient." - Sometimes that small clarification is all you need.
I have a project where some spaces will be left for future use, while most of others are designed and built for immediate use. I am wondering if I must include them as conditionned or unconditioned zone.
You will want to review 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. 10102 in detail (assuming it was posted before your project was registered). There are a variety of additional requirements for LEED-NC projects which include incomplete spaces like you describe.
For EAp2/EAc1, my understanding is that the energy model should be simulate those spaces as fully fit-out with the fit-out being identical in both the baseline and proposed cases (i.e. you can't claim any savings in those future spaces). This essentially means that the rest of the building/areas you fit-out now will need to be just a little more efficient to help carry the unknown/potential energy use of the incomplete spaces.
Thank you very much.
That is my interpretation of table G3.1, too. Those spaces may be simulated fully fit-out as office spaces by default.
The project comprises four hospital buildings, called B, C, D and E, and each building is registered as an individual project on a campus basis. A chilled water plant, located at the roof of building C, serves buildings B and C. According to the document “Treatment of District or Campus Thermal Energy in LEED® V2 and LEED® 2009 – Design & Construction”, of August 2010, if a central plant does not serve other buildings not within the LEED project boundaries for the project, the plant is not defined as a District or Campus Energy System – DES. This inquiry is to confirm that:
1. Since buildings are not grouped as a single LEED project, the central plant shall be treated as a DES and compliance shall be demonstrated following one of the following options:
Option 1 (streamlined): the building stand-alone scenario, with 12 points cap, i.e. the central plant is modeled as purchased energy for both the baseline and proposed case energy models, with no direct accounting of the district network’s efficiency, and a restriction of the maximum number of points that can be earned under EAc1.
Option 2 (full accounting): the aggregate buildingA streamlining method. USGBC offers this method only for a few select LEED credits that are often implemented and the results tracked for groups of buildings, i.e., the LEED-EB materials purchasing credits. The volume customer reports the sustainable performance for the whole group or for defined sub-groups, along with its method of verifying that the performance of each building within the group is similar (though not necessarily identical) to that of the group as a whole. Similar performance across the buildings is required; this is NOT intended as a method of simply averaging widely different performance within the group.
A credit-level QC plan and Education plan are required for this method. / DES scenario with 8 points floor, i.e. the efficiency of the central plant is directly accounted in the proposed case energy model, baseline case is modeled according to standard ASHRAE 90.1 baseline system, and the project must achieve a certain minimum number of points under EAc1.
2. In order to the central plant not to be treated as a DES, buildings B and C should be registered under a single group project.
Your interpretation for both item #1 and #2 above sound correct to me.
Actually I'am not able to correlate section 14 required inputs under pressure drop column "CFMd", and the requirements of ASHRAE TABLE 126.96.36.199.1 B in (pascals/ in.w). In other words; how can I know the allowable increase in cfm to compensate for using one MERVMinimum efficiency reporting value. 13 filter, or for using fully ducted system for example?
The software should be auto-sizing the baseline system airflow so no need to try and "design" it by increasing the cfm. You can double check your baseline fan power calculations using the spreadsheet found in the Documentation Toolkit tab above.
The baseline pressure drop adjustments are intended to compensate for the effect on the baseline fan power related to issues like MERVMinimum efficiency reporting value. 13 filter and ducted returns. So you don't do any further adjustments.
then I understand that I can leave this part blank on the Section 14 table, is that correct? and in this case allowable fan power won't be increased
Probably not. In general you need to completely fill in the Section 1.4 tables. I am not sure which version of the Section 1.4 tables you are using or even specifically what you are suggesting that you could leave blank.
The allowable fan power is automatically adjusted by the pressure drop adjustments.
Iam using the "Revised Section 1 4 Tables (Dec 2012)", in the Air-Side HVAC details; whenever I increase the CFMd, the allowable fan power (cell D-30) increase, giving me more allowable fan power, so I need to get use of this allowance, in the same time I don't know the appropriate cfm drop to enter
OK. In Table 1.4.7A it is important to know that you should enter each separate system in its own column or the fan power calculations will not be 100% accurate. You would enter the cfm of supply air from the energy model. You then enter the cfm associated with any of the applicable pressure drop adjustments in the bottom of the form. For example, do not enter the supply cfm for ducted returns unless 100% of the supply air is returned. Use the same proportions as the corresponding proposed system (if the return is 90% of the supply in the proposed apply this proportion to the Baseline). The spreadsheet will then accurately calculate the allowable baseline fan power for each system. Make sure to read the instructions and notes at the top of the page to make sure it is working right.
Thank you Marcus. I have another question; now my proposed fans' power are exceeding the Baseline fan power, should I model it the same as basecase fan power, or as found in the design drawings?
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EAc1 relies directly on the EAp2 documentation, and the strategies to earn the prerequisite are often similar to earning points under the credit.
Limits on interior and exterior light use can help in reducing energy loads.
Daylighting reduces demand on installation and use of lighting fixtures resulting in energy use. To full realize the energy benefits, contorl electrical lighting with daylight sensors.
Commissioning of energy-efficient building systems helps realize he operational benefits of the design.
Onsite renewable energy contributes to prerequisite achievement if pursuing energy modeling under Option 1.
The computer model developed for EAp2 – Option 1 is used in the M&V plan.
Do you know which LEED credits have the most LEED Interpretations and addenda, and which have none? The Missing Manual does. Check here first to see where you need to update yourself, and share the link with your team.
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