USGBC's membership approved an update to LEED 2009 effective April 8, 2016. The update only affects LEED 2009 projects registered on or after that date.
Project teams will be required to earn a minimum of four points in EAc1, effectively making EAp2 more stringent. The referenced energy standard and modeling requirements are not changed. Buildings falling under the proposed change can use the same methodologies and referenced standards, but will need to earn additional points in order to achieve certification.
The intent of the change is to bring LEED 2009 energy requirements more up to date, as LEED 2009 continues to be the predominant LEED rating system, even though the more up-to-date LEED v4 has also become available.
This prerequisite is a big one, not only because it’s required for all projects, but also because it feeds directly into EAc1: Optimize Energy Performance, where about a fifth of the total available points in LEED are at stake. Master these minimum requirements, and you can use the same compliance path as in EAp2 to earning points.
You won’t earn the prerequisite by accident, though. Although “energy efficiency” is on everyone’s lips, the mandatory and performance-based requirements for EAp2 go beyond code compliance in most places. That said, there is nothing to stop you from meeting the requirements with a reasonable amount of effort, and the environmental benefits as well as the operational cost savings are significant.
Most projects start by choosing which of the three available compliance paths to follow. We’ll look at them each in turn.
Option 1 alone gives you access to all of the points available through EAc1, and offers the most flexibility in giving you credit for innovative designs.
First, you need to meet the mandatory requirements of ASHRAE 90.1-2007 for all major components, including the envelope, HVAC, lighting, and domestic hot water. ASHRAE 90.1 has had some changes and new mandatory requirements since the 2004 version, which was referenced on previous LEED systems, so be sure to review the standard carefully.
Energy efficiency is an area where it behooves project teams to start early and work together to maximize savings. Playing catch-up later on can be costly.Second, you need to demonstrate a 10% savings (5% for existing buildings) for your designed building compared with a baseline case meeting the minimum requirements of ASHRAE 90.1 (or Title 24-2005, Part 6 for California projects). You do this by creating a computer model following rules described in Appendix G of ASHRAE 90.1.
Computer modeling offers the following key advantages:
Your building type may not have a choice—you may have to follow this path, because both Options 2 and 3 are prescriptive compliance paths that are only available to specific building types and sizes.
However, if your building type and size allow, and you don’t want to embark on the complex process of computer modeling, which also requires expert assistance from a modeler or from a member of the mechanical engineer’s team, the prescriptive compliance paths are a good way to earn the prerequisite simply by following a checklist.
Passive design strategies such as shading to reduce solar heat gain are the most cost-effective ways to improve energy performance.Note, however, that when you get to EAc1, there are a lot fewer points on the table for the prescriptive paths, and that you have to follow each prescriptive requirement. These paths also require more collaboration and focus early on in design than you might think. The design team must work together to integrate all of the prescriptive requirements, and Option 3 even requires documentation of certain design processes.
The Advanced Energy Design Guides are published by ASHRAE for office, warehouse, and retail projects less than 20,000 ft2—so if you don’t fall into one of those categories, you’re not eligible for this path.
These guides outline strategies to reduce energy use by 30% from 2001 levels, or an amount equivalent to approximately 10%–14% reduction from ASHRAE 90.1-2007. If you choose this compliance path, become familiar with the list of prescriptive requirements and commit to meeting all of them.
The Core Performance Guide path is a good option if all of the following are true:
Comply with all requirements within Sections 1 and 2 of the guide. If you choose this path, become familiar with the list of prescriptive requirements and commit to meeting them. Also note that it’s not just a list of prescriptive requirements, but a prescribed process for achieving energy efficiency goals. You must demonstrate that you considered a couple of alternate designs, for example, and that certain team meetings were held.
Energy efficiency offers a clear combination of environmental benefit and benefit to the owner through reduced operational expenses, and potentially reduced first costs, if you’re able to reduce the size and complexity of your HVAC system with a more efficient envelope.
High-tech HVAC systems, and onsite renewable energy generation are often signature components of green buildings, but consider these strategies more “icing” on the cake, rather than a place to start. Start with building orientation and passive design features first. Also look at envelope design, such as energy-efficient windows, walls and roof, before looking at HVAC and plug loads. A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective.
Projects connected to district energy systems will not be able to utilize the system efficiencies of the base plant to demonstrate compliance with the prerequisite. They can plan on benefiting from these systems under EAc1, however.
Focusing on energy efficiency and renewable energy generation can seem to add costs to a project, but there are a variety of utility-provided, as well as state, and federal incentives available to offset those premiums. (See Resources.)
Ideally if the software you are using cannot model a technology directly then seek a published workaround related to your software. If you can't find a published workaround then model it as you think it should be modeled and explain how you have modeled it in the preliminary LEED submission.
No, not if it is part of the LEED project. However, there is an exemption for existing building envelopes in Appendix G that allow you to model the existing condition in the baseline so you do not pay a penalty.
No, not for an existing building.
You must model accurately. Since you don't have enough savings in the building energy, find savings in the process. Either you will be able to demonstrate that compared to a conventional baseline the process being installed into the factory is demonstrably better than "similar newly constructed facilities," allowing you to claim some savings, or the owner needs to install some energy-saving measures into the process to get the project the rest of the way there. Either option can be difficult, but not impossible.
Account for process load reductions through the exceptional calculation method. A baseline must be established based on standard practice for the process in your location. Any claim of energy savings needs a thorough narrative explaining the baseline and the strategy for energy savings along with an explanation of how the savings were calculated.
It is common to have a 80%–90% process load in a manufacturing facility. The 25% default in LEED is based on office buildings. If you think your load is lower than 25%, it is recommended that you explain why in a short narrative. It is also recommended to briefly explain it if your load is 25% exactly, since that level commonly reveals that the process loads were not accurately represented.
The energy savings are based on the whole building energy use—building and process. LEED does not stipulate exactly where they come from.
For LEED 2009 you'll need touse 90.1-2007. There were some significant changes in 90.1-2010—too many to account for in your LEED review, and your project would also have a much harder time demonstrating the same percentage energy savings.
Yes according to LEED, although it is not recommended as a best practice, and it is usually more cost-effective to invest in energy savings in the building.
You can assume exterior lighting savings for canopies against the baseline, but not the shading effects of canopies.
If exterior lighting is present on the project site, consider it as a constant in both energy model cases.
Any conditioned area must be included in the energy model.
The Energy Star portion of the form does not apply to international projects.
Use the tables and definitions provided in 90.1 Appendix B to determine an equivalent ASHRAE climate zone.
International projects are not required to enter a Target Finder score. Target Finder is based on U.S. energy use data.
For Section 126.96.36.199c, 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:
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 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.
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 and CS Appendix 2: Energy Modeling Guidelines. 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.
Core and Shell projects must mandate the requirements for the tenant spaces within a tenant guideline document such as one developed for SSc9: Tenant Design and Construction Guidelines.
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.
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.
The architect and HVAC engineer should agree on the design, working with the cost estimator and owner.
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 Core and Shell Development
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.
Projects in Brazil that are certified at the “A” level under the Regulation for Energy Efficiency Labeling (PBE Edifica) program for all attributes (Envelope, Lighting, HVAC) achieve this prerequisite. The following building types cannot achieve this prerequisite using this option: Healthcare, Data Centers, Manufacturing Facilities, Warehouses, and Laboratories.
1Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
2 Projects outside the U.S. may use an alternative standard to ANSI/ASHRAE/IESNA Standard 90.1-2007 if it is approved by USGBC as an equivalent standard using the process identified in the LEED 2009 Green Building Design and Construction Global ACP Reference Guide Supplement.
The following pilot alternative compliance path is available for this prerequisite. See the pilot credit library for more information.
EApc95: Alternative Energy Performance Metric ACP
Design the building envelope and systems to meet baseline requirements. Use a computer simulation model to assess the energy performance and identify the most cost-effective energy efficiency measures. Quantify energy performance compared with a baseline building.
If local code has demonstrated quantitative and textual equivalence following, at a minimum, the U.S. Department of Energy (DOE) standard process for commercial energy code determination, then the results of that analysis may be used to correlate local code performance with ANSI/ASHRAE/IESNA Standard 90.1-2007. Details on the DOE process for commercial energy code determination can be found at http://www.energycodes.gov/implement/ determinations_com.stm.
1 Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
2 Projects outside the U.S. may use an alternative standard to ANSI/ASHRAE/IESNA Standard 90.1‐2007 if it is approved by USGBC as an equivalent standard using the process located at www.usgbc.org/leedisglobal
Useful web resource with information on local/regional incentives for energy-efficiency programs.
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.
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 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.
Sample LEED Online forms for all rating systems and versions are available on the USGBC website.
Documentation for this credit can be part of a Design Phase submittal.
Has anybody noticed issues with the Minimum Energy Performance Calculator for version 2009. I have noticed a few issues where the formulas don't work properly. For example it wont apply the Lighting Adjustments with Occupancy sensors are used. Will LEED except Table 1.4 instead as I have fill this out already for EAc1. It contains much of the same information.
Yes they will accept the prior version.
Do tankless Electrical water heaters have to comply with any efficiency requirements, in order to comply with the 7.4 mandatory provisions? On table 7.8 the performance requirements for electrical water heaters seem to depend of the rated volume.
No, they are not regulated.
I’m working in a Core & Shell building in Bogota, Colombia. The project was signed up in Leed Online in April 2016 (V3 – LEED 2009), therefore V07 form appears for EAp2 and V06 form for EAc1. In these forms I can’t mark that I’m going to use the Alternative Compliance Path (ACP EAp2-c1). How should I document the additional points? I have 15% of savings, which means 4 points, but if I use the ACP the project will get 17 points. Is the ACP integrated in the minimum energy performance calculator? If it is integrated, how should I use it?
It does not show up because the new forms were created for v4 and then revised for 2009. This ACP is not applicable to v4.
I would provide the spreadsheet along with a narrative explanation.
Thank you Marcus
As you know, in V05 form, projects not located in the United States were not able to get a Target Finder Score. In V07 form, must international projects use this tool?
I think that exemption still applies.
I have an office project which is designed to use a little compicated HVAC system. There are 3 Central Heat Recovery Units on the roof top to provide pre-cooled/heated fresh air for the whole office building. Then the pre-cooled/heated fresh air will be delivered to the AHUs with 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. control located on each floor. The mix air supplie from AHU will go out through the terminal chilled beam/panel installed in the inner office space, which is only have cool function. In the perimeter area, it is designed to use FCUs with both of heating and cooling modes.
I will use eQuest software to do the energy simulation for the building. But I'm not confident how to model it and which kind of system is the most similar with it?
Could anyone help me?
Really appreciated in advance!
I don't think eQUEST can model chilled beam but you might want to check on the eQUEST Users group at onebuilding.org.
Modeling a similar system may not be good enough. If eQUEST cannot model this system directly and there is not a published work around for how to closely simulate it then you will have to propose your own work around and justify its accuracy to the reviewer. Make sure you submit it as an exceptional calculation. However, if you are not confident enough about how to model it then this route is probably not the best one for you.
It is important to understand that if the software you want to use cannot model a strategy or system in the design then you should probably not use that software for your model. We modeled a project with a double facade a few years back and eQUEST cannot handle that system so we used Energy Plus. Depending upon what you find out about the capabilities of eQUEST you may need to consider something else.
Many thanks, Marcus!
I need to model in Energy Plus several "Air - Water Heat Pumps": heat pumps that use air as energy source and water as fluid for conditioning. Do you Know how it is possible to model these systems in Energy Plus?
Thank you so much.
You may get a response here but you might be better off posting your specific Energy Plus questions on one of these forums. Of course search the archives first before posting.
Thank you very much Marcus.
I'll try to post my questions on one of these forums.
I would like to check if the Carrier model 30RQ0262 (COPc=2,62 according ARHI test 550/590 despite ASHRAE requires ARI 340/360) will meet that Mandatory Provisions in terms of Equipment Efficiency.
after perform hole buidlign simulation, the result using this units is 30% reduction.
Additionally we have checked the 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 ID#2305 +ID#10028+ ID#5938 – “Option 1 - Whole Building Simulation, offers the flexibility that the project team requires. Applicable Internationally.” Y “the project is requesting confirmation of non standard (ARI) testing methods for the proposed equipment efficiencies”
Which table are you looking at in 90.1?
I think this air cooled scroll chiller comes under Table 6.8.1C which does reference ARI 550/590.
As this is a heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source., cooling and heating, (air to water) [http://ahi-carrier.at/wp-content/uploads/2012/pdf/30rq/30RQ_PSD.pdf] in my view it should be considered according table 6.8.1.B
in that case, Air Cooled, >70kW, all other, before (1/1/201), the minimum, that’s what I want to check, is 2.58 COPc? Which does reference ARI 340/360 instead of 550/590?
I don't think this air to water heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. is actually regulated at all by 90.1. The air cooled heat pump you reference is air to air. If you look at ARI 340/360 I am pretty sure it only covers air to air heat pumps.
I would think that Carrier would understand the correct standard to test the equipment under. In my opinion the cooling side is addressed by 6.8.1C and the heating side is simply unregulated so it does not have a specific requirement.
Yes, in fact the ARI 340/360 only covers air to air heat pumps.
Since the building occupancy is very low (12%) and the owner wants to upgrade the façade, lighting system, including C02 demand ventilation system, and also to include additional common areas into future tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space., we have proposed them to pursue LEED CS. According the whole building simulation with the new elements and maintaining the two air to water heat pumps (replaced last May 2015) the overall savings will be about 30%. However we have the minimum energy efficiency mandatory provision 6.8.1C, but these two air to water heat pumps (replaced last May 2015), are “simply unregulated so it does not have a specific requirement.”
In my view it will be very unsustainable to replace these two air to water heat pumps, to meet the minimum energy efficiency mandatory provision, even when the Whole Building simulation proves important saving and additionally these heat pumps are unregulated on 90.1. Does it make sense? Shall we maintain these heat pumps?
thanks in advance for your apprecaited support
I think you could use this equipment. You can make the case that this equipment is not regulated by 90.1. When a piece of equipment is not regulated its efficiency is not subject to compliance with the mandatory provision for minimum efficiency.You should provide the reviewer a narrative describing why the minimum efficiency does not apply.
Thanks Marcus, We will do it.
I am working on project whereat a big retail store wants to use automatic sliding doors for their shop entrances.
According to ASHRAE 90.1-2007, 5.4 Mandatory Provisions -> 5.4.3 Air Leakage -> 188.8.131.52 Fenestration and Doors, the air leakage shall not exceed 2.0 L/s*m² for that product. The manufacturer of the doors states that it is impossible to meet this requirment (they say a limit of 5.0 L/s*m² would be possible).
ASHRAE 90.1-2007, p.18: "Air leakage shall not exceed 5.0 L/s'm2 for glazed swinging entrance doors and for revolving doors and 2.0 L/s·m2 for all other products."
The automatic sliding doors will be used in vestibules. As I interpret it, the requirement is still 2 L/s*m², right?
Has anyone used automatic sliding doors that meets the requirement? Or any other suggestions to solve that problem?
Will they be used for the inside or outside of the vestibule? If outside then I agree that the requirement you note applies.
You might want to look at 90.1-2013 as there are more detailed requirements for additional fenestration/door types.
We have an existing building whereby some of the existing glass will remain however we cannot determine what the thermal properties of the glass is because there is no documentation and the manufacture is out of business at least 15 yrs ago. How can we make this determination?
A second question then is the base case - do we create from the existing building or use as prescribed by ASHRAE 90.1?
Use Table A8.2 in 90.1 to provide the estimated performance values.
You can use the existing value according to Table G3.1-5 Baseline (f).
Dear fellow modelers,
I have a query regarding modeling and saving percentage calculation for datacenter buildings for LEED CS -2009.
I have modeled the datacenter building with its actual process load and actual parameters/ values to cool building and process equipment’s. Now for considering the savings, I need suggestion from you, that what should be the actual way of considering its savings as per LEED, and any exceptional calculations required.
1. Considering savings for full building including every consumption (process consumption)– In this case project is achieving 2% saving, as process consumption is very high.
2. Considering savings for building only (excluding both the process electrical energy consumption and HVAC energy consumption to cool process equipment/data center equipment) – in this case project is achieving around 8% savings.
3. Considering savings for building (excluding the process electrical energy consumption, but including the HVAC energy consumption to cool data center process equipment’s, and general space both) – in this case project is achieving around 33% savings, as HVAC systems are very efficient (HVAC to cool spaces, and HVAC to cool datacenter equipment’s both are very efficient).
It’d be great to have your suggestions on this.
1. It needs to be the full consumption.
2. Not allowed.
3. Not allowed.
Are you using the calculator?
Thanks for your reply. Just guide me a thing more. The Baseline case for this 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. says to install economizerAn economizer is a device used to make building systems more energy efficient. Examples include HVAC enthalpy controls, which are based on humidity and temperature., so shall this economizer unit need to be installed on computer room HVAC units as well?? They are just cooling the process equipment of data centers.
Any equipment that is 100% for a process is not regulated and must be modeled identically in both models based on the proposed design. An example is a data center might be a chilled water system that directly cools the equipment and does not necessarily condition the air around the equipment. If the cooling equipmentThe equipment used for cooling room air in a building for human comfort. cools the equipment by cooling the air around it you are in a grey area because that equipment typically will be providing conditioning for the people in the space as well.
I don't see any applicable exceptions for data centers in 90.1-2007. 90.1-2013 does more explicitly address economizers in computer rooms so you could try to make the case for an exception using that version of the standard.
I am modeling an existing building right now. The opaque envelope will be maintained (walls and roof) but the entire inside, all HVAC systems, and windows will be replaced. For the model, I will model the HVAC systems as proposed against Appendix G systems. For the windows, do I use the baseline from Table A8.2, or can I use the R-value of the old building windows (which will likely be worse than Table A8.2)? And for the opaque envelope, we do not have an accurate way of measuring the current R-value. Can I just use the values from Table 5.5 for both the baseline and proposed (and therefore assume no savings from the opaque envelope? We are planning on adding some insulation to the opaque walls, but since there's no accurate way of measuring the existing structure, I assume we can't take any savings there. Am I correct? Thanks!
You can use the data for the old windows according to Table G3.1-5 Baseline (f). You must be able to document the performance of those windows. If you can't use the Table A8.2 values.
You don't need to accurately measure the current R-value. It can be derived based on the construction assembly. If you can show that using the Baseline values is a conservative approach it would likely be accepted. Again you don't need to measure the existing structure anymore than you "measure" a new design. You can claim savings for adding insulation to existing walls by estimating the R-value of the assembly before and after.
We have a canteen project in Shanghai. The building has three floors, total GFA is 64,067 square feet. The baseline HVAC system type is system 6.
In the second floor, there are only two air conditoned zones, dining area (12,588 sf2) and restroom (415 sf2). The dining area need to use DCV in baseline system. We have two questions about the model of eQUEST:
1. Do we need to use system 4 for the dining area and system 6 for the restroom? or both use system 6? or system 6 for the dining area and system 4 for the restroom?
2. Shall we use the minimum ventilation rates for the baseline system?
1. See Section G3.1.1. For a system 6 you need to model it in the baseline as a system per floor. You also must apply any of the applicable exceptions to G3.1.1.
2. The ventilation rates must be identical to the Proposed unless the Proposed has DCV.
We have a building which is going under major renovations, one of the most important is replacing old operable windows by new windows with new frames and glasses. The new fenestration is fabricated on siete in an artisanal way.
Will these new windows applay for the exeption to not meet the infiltration requirements?
It sounds like it. Field fabricated windows are excepted.
Thank you Marcus
Our project is a manufacturing plant which is seeking certification under NC Core and Shell v2009. The building will have a high process load (could be 50%) but the equipment has not yet been selected. We’ve been told that this equipment will be significantly more efficient than other similar plants but we don’t have data on the new equipment or any existing facilities to validate the claim. The process is somewhat unique and there are very few existing facilities which are similar. I’m not sure how to approach the process loads in the energy model and meet the intent of the credit. If we use COMNET Appendix B process loads for a manufacturing (0.86 W/SF), our process loads will be low. If we calculate the process loads based on the electrical service, our process loads will be high (25 W/sf). The problem I am having is that I don’t know where in the middle it will fall or how to justify whatever point I choose. I don’t want it to appear that I am manipulating the process loads to get energy savings. Has anyone had a similar situation?
Ultimately you are required to model it as designed.
For a process like you describe you cannot simply pick a number to include in the model.
During the design process to get started you can use general values. For example you indicate that you know the process could be 50%. If that is based on other similar plants it would not be hard to simply enter some loads in the model so that the process is about 50%.
For a specialized process you can't use a rule of thumb. You have to figure out a way to model it so that it is accurately represented in the model.
please help me with these questions:
1) I'm not sure how to specify a water heating equipment performance. In many cases the baseline building has to have an electric resistance heating of DHWDomestic hot water (DHW) is water used for food preparation, cleaning and sanitation and personal hygiene, but not heating.. So Table 7.8 provides two options <12kW and >12kW. I assume this is a DHW system peak load value. For <12kW there is equation 0.93-0.00132*V where V is rated volume in gallons. But "rated volume" of what? Volume of water storage? But what if there is no water tank? In that case would be the performance 93%?
Total water storage is 2000 L (439.93 gall (IP)), peak DHW load is under 9kW.
<12kW: 0.93-0.00132*439.93 = 0.349 = 34.9% eff - is this correct? It's pretty bad efficiency, isn't it?
Office building with various electric water storage tanks in range from 10L to 1000L. DHW peak load is approx. 800kW.
The V in this case should be the total water capacity (approx. 12 200 L)?
>12kW: 20+35*√V = 1833.12 BtuA unit of energy consumed by or delivered to a building. A Btu is an acronym for British thermal unit and is defined as the amount of energy required to increase the temperature of 1 pound of water by 1 degree Fahrenheit, at normal atmospheric pressure. Energy consumption is expressed in Btu to allow for consumption comparisons among fuels that are measured in different units./h = 0.5371 kW = 0.00105 kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu./l*day. OK but still don't know what is the heating equipment efficiency... Because in any simulation program you are required to define it of course. Should it be 100%?
2) we work on project with DES heating. It's LEED v2009 CS and we have chosen Option 1. From what I read in guidance for DES in LEED I understand that baseline heating source shall be modeled with all system parameters as specified in Apendix G if Table 3 of the guidance is not modifying it. It means that all baseline heating equipment efficiency and resets remains the same as it would be modeled without DES right? (but only for Option1)
Thank you very much in advance for any help, mainly with DHW efficiency.
1. Size is the capacity of the elements, not the peak load. It is the volume. If it has no tank then it is an electric instantaneous heater which is not regulated. So it would be modeled identically in the baseline.
2. Under Option 1 you model purchased heat so while there may be no change listed in Table 3 you do not model a boiler and associated equipment in the baseline.
Hello! I had submit a project for cs2009, and got some comments confused. The project is a high rise building consists of retails, restaurants and offices.
1. Table 1.4.6 and Table 1.4.7A indicate that system 7: VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with reheat systems are the only HVAC system type reflected in the Baseline model; however, it appears that the project includes spaces that may meet the requirements of exception (b) of Section G3.1.1 (e.g., data/telecom rooms, kitchens, movie theaters), which may require an additional system type to be reflected in the Baseline model. Additional system types must be included in the Baseline model if an exception to Section G3.1.1 is met. If an exception to Section G3.1.1 is met, revise the Baseline model, as needed, to include the appropriate additional system types for these spaces. In addition, update Table 1.4.6 and Table 1.4.7A, and provide SV-A reports for each additional system type reflecting the changes.
We understand that data rooms and movie theaters have different schedule rather than other spaces need additional baseline system. But why kitchens need additional system? For kitchens, there are only supply fans and exhaust fans. They are not common conditioned area, don’t need to be cooling or heating. In my previous model, I just put the fan power in the electric meter directly. If I was wrong, which system should be used for kitchens? System 3?
2. Table 1.4.4 indicates that 119.1 kW exhaust fans have been included in each model; however, it is unclear if all of the independent fan systems listed in the mechanical schedules provided for PIf4: Schedule and Overview Documents have been modeled in the Proposed and Baseline cases. In addition, it is unclear if the exhaust fans and/or ventilation fans in the parking garage (as applicable) are included in each model. All independent fan systems of the HVAC systems in the actual design must be modeled identically between the Proposed and Baseline models at actual equipment capacities (fan volume and fan power) as required by Table G3.1.10 in the Proposed building column, since the fan design air flow rates and fan power per Sections G184.108.40.206 and G220.127.116.11, respectively, only applies to system types 1 through 8 in Table G3.1.1A. Revise the Proposed and Baseline models, as needed, so all independent fan systems of the HVAC systems are modeled identically between the Proposed and Baseline models. In addition, separate the energy consumption and peak demand power for independent fans and parking garage fans in Table EAp2-4 and Table EAp2-5 of the form. Furthermore, provide sample simulation input summary reports or screenshots for each model reflecting the changes.
What’s the independent fan mean? Is toilet fan and kitchen fan independent? In my previous model, I just put the fan power in the electric meter directly. Is this comment mean that I should set unit ventilator in baseline and proposed model identically not put the fan power in the electric meter?
1. A kitchen could meet the peak thermal load difference references in exception b. If the exception applies it would be a system #3.
2. Any fan not tied into the HVAC system fans is an independent fan. Toilet and kitchen fans may or may not be independent. It depends on if they are at all connected to the controls associated with the HVAC system serving that area. An obvious example would be a parking garage exhaust fan or any other exhaust fan serving an unconditioned space. These must be modeled identically in both models, you should report them separately in Tables EAp2-4 and EAp2-5, and mark them as a process load with in the form.
But in actual design, kitchens have no air conditioning system, only ventilation. Also need to use system #3?
Then the exception does not apply so model the ventilation system identically in both models as a process load.
OK! Thank you very much!
Hi LEED Users,
I hope it is correct to model renewable energy system only in proposed building as our advantage against baseline.
Please coorect me if I'm wrong.
You are correct.
We designed the Core & Shell of this building as one project - and subsequently also designed most of the tenant occupancies, so we know that there are savings in the lighting for the various tenants. As I'm filling out EAp2, if I pick "In Scope" in order to incorporate the savings in the lighting from my tenants, does that mean that *all* of the credits would have to incorporate the tenant build-out also? Specifically, the construction team has tracked their materials usage for the Core & Shell for the various MR credits - but they might not have kept track so much when building out the tenants, since this was a LEED C&S project.
Claiming energy savings in the tenant spaces does not create a requirement to include the tenant spaces in the documentation of other credits.
We are working on a very large, core and shell project that the owner will not share the tenant agreement with our team. The minimum code requirements are based on IECCInternational Energy Conservation Code 2012/ASHRAE 90.1-2010. We were instructed to design the dedicated outdoor air unit for the building (common and tenant) to accommodate variable refrigerant flow system. The common area HVAC system is a variable refrigerant flow system.
First the Code question…
Is it correct to assume that the baseline lighting is based on ASHRAE 90.1-2007 and proposed lighting is ASHRAE 90.1-2010 along with the new daylighting requirements in ASHRAE?
Second the tenant improvement question…
Is it correct to assume that the proposed mechanical system for the tenant is a variable refrigerant flow system?
I welcome your thoughts.
Code - yes and yes.
TI - No. You cannot claim any savings related to the tenant spaces without the requirements being in the tenant lease agreement or without them being designed as part of the CS submission. Without one of those two you must model the tenant space HVAC identical to the baseline.
We started up a LEED for CS version 4 project and got really good results for the energy model. The owner wants to double certify the building so it also will earn LEED for CS version 2009 certification. Would it be possible to use the v.4 energy model to the v. 2009 certification? It's more stringent so I imagine it would be fine.
Yes you can. There is a revised point scale you can use.
I’m working on a Core & Shell office building in Bogota and the baseline system is 8. The building has a central cooling system with chillers and air handle units in each floor, it doesn’t have a heating system. According to the G3.1.10 (c) table of ASHRAE 90.1, the proposed model must have a heating system equal to the baseline, ie electrical resistance and parallel fan-powered boxes (PFP). I don’t want to model PFP boxes in the proposed model due to the fan power consumption. I don’t want neither to model a lower heating temperature setpoint because the fan in the PFP box would be working all the time.
To meet the baseline heating system, Can I use only an electric resistance in the air handle unit or placing a simple reheater in the zone enough? Or is necessary to model PFP boxes with a heating coil in each zone?
If you follow this path you have to model the proposed identical to the baseline. You can't choose to model it a different way that would be to your advantage.
Personally I would just explain to the reviewer that you have not modeled a heating system while demonstrating that a heating system would not result in any heating energy use. If you can do that as a reviewer I would be OK with you not modeling a heating system as it represents a more accurate prediction of future energy use.
Thank you Marcus.
In system 8, heating system for the baseline uses an electric resistance. My question is, Can I model the heating system using only an electric resistance in the AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork.?, Or the only way for modeling the heating system is including a PFP box with reheat?.
You have to model it in the box with reheat.
The proposed building is a dormitory served using individual fan coils (with no outside air in the fan coils) and the outside air for the building being supplied by a single dedicated outside air unit. The dedicated outside air unit is over 5000 cfm and is 100% outside air. In the proposed building, the dedicated outside air unit has a heat recovery wheel.
The baseline building is required to be a type 2 system (PTAC with gas boiler heat). There are not any individual spaces that require 5000 cfm or over 70% outside air.
Is the baseline building required to be modeled with energy recovery because my proposed dedicated outside air unit meets the requirements of G18.104.22.168 (since we choose to group all the exhaust together to recover the energy)? Or can the baseline building be modeled without energy recovery?
Energy recovery in any proposed system does not affect whether energy recovery is in a baseline system.
So the first question - No.
Second - Yes without energy recovery as far as I can tell.
I have one simple question. According to section G3.1.1 of ASHRAE 90.1 Standard each floor for system 5 through 8 shall be modeled with a separate HVAC system. I hope it doesnt mean that each floor shall have its own heating and cooling source but only AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. per floor and these AHUs will be supplied by one central heating/cooling source (or more central sources according to section G3.1.3).
I definitely prefer the second option but I rather ask.
Thank you in advance.
For a system 5 and 7 the heating is a centralized boiler system. For system 5 and 6 each system has DX cooling. For system 7 it is also centralized cooling which is also the case for system 8. So whether the heating and cooling source is central or within each system varies depending on the system in question.
Thank you Marcus for your help.
I would like to ask another one question:
I have office building where 30 000 m2 (cca 323 000 ft2) is office space (system 7) and almost 15 000 m2 (cca 161 500 ft2) is for parking, what system type I should choose for the garage? Should I follow section G3.1.1b and choose system 3 because of significant difference in occupancy and process loads? And then eliminate heating and cooling loads for garage HVAC system by setting up an unachievable 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.... Could it be like that?
Sounds like the parking garage is unconditioned (no heated or cooled)? If so you don't model any system in either model.
Yes that's right, it is unconditioned space of course, but it is underground garage and there are several extract fans for removal of exhaust gases. So I thought that it is necessary to model every end-use load components as stated in Table G3.1.1a. Therefore I was looking for solution how to model energy consumption for parking garage fans in baseline building.
Please correct me if I'm wrong but I thought if proposed building has any energy consumption so the baseline has to have too.
That table only applies to conditioned spaces.
The exhaust fans in the garage are process loads and would be modeled identically in both models. You can claim savings for demand controlled ventilation based on CO as an exceptional calculation if this strategy is not required or common practice in your location.
Thank you Marcus, I appreciate your help.
Hi all, I have LEED CS with very minimum client provision without AC systems (only emergency lights, emergency fans and lifts). But the main tenant has been agreed from the building and the entire building is tenanted to this tenant only. My question is:
1. Should we model the energy modelling based on only client provision or we can include the tenant provision, since it is agreed from the beginning of this project and we have tenant energy systems data? Since landlord provision is very minimum.
2. Are we allowed to include tenant energy system data for LEED CS project?
3. Any official documents indicate the answer for my question 1 and 2? (eg. MPR, Reference guide etc)
1. Yes you can model the tenant design and claim energy savings associated with it.
3. Not sure I would have to go digging. Start with the Reference Guide.
Thanks Marcus for your opinions. I still have something in mind.
1. If we can exclude the tenant design, how we show the improvement from ASHRAE 90.1? Since the building energy consumption will be extremely very low due to minimum provision of energy related system from the developer.
2. I've noticed as well based on ID #2084, it seems like even we don't have HVAC and lighting design from tenant. We should model HVAC and lighting according to ASHRAE 90.1. Am I correct?
3. If we should model HVAC and lighting design, should we include some assumptions on the potential tenant’s future provision, eg. Chiller plant, air-distribution system, interior lightings, plug loads, etc? or we can follow certain guideline for the HVAC sizing?
1. CS projects must include all energy use in the core areas shared by tenants and due to the influence of the building shellThe exterior walls, roof, and lowest floor of a building, which serve to separate and protect the interior from the elements (precipitation, sunlight, wind, temperature variations).. In most areas the building shell influences heating and cooling energy use so this is included and any envelop improvements can be used to show savings. If the CS scope is extremely minimal as it impacts energy savings then it does get much harder to meet the minimum energy savings.
2. Yes if there is no tenant design or provisions in the tenant lease agreements, then the tenant spaces are modeled identical to the baseline.
3. If you are modeling a design then you model that design. There should be no assumptions regarding HVAC or lighting and the HVAC should be modeled using the capacities in the design, not following some guideline.
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