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:
The energy model itself will not account for any change in plug loads from the baseline case, even if your project is making a conscious effort to purchase Energy Star or other efficient equipment. Any improvement made in plug loads must be documented separately, using the exceptional calculation methodology (ECM), as described in ASHRAE 90.1-2007. These calculations determine the design case energy cost compared to the baseline case. They are included in the performance rating method (PRM) table or directly in the baseline and design case model.
Besides energy modeling, you may need to use the exceptional calculation methodology (ECM) when any of the following situations occur:
Some energy-modeling software tools have a daylight-modeling capability. Using the same model for both energy and IEQc8.1: Daylight and Views—Daylight can greatly reduce the cost of your modeling efforts.
Provide a copy of the AEDG for office, retail, or warehouse, as applicable, to each team member as everyone, including the architect, mechanical and electrical engineers, lighting designer, and commissioning agents, are responsible for ensuring compliance. These are available to download free from the ASHRAE website. (See Resources.)
Find your climate zone before attempting to meet any detailed prescriptive requirements. Climate zones vary by county, so be sure to select the right one. (See the Documentation Toolkit for a list of climate zones by county.)
Develop a checklist of all requirements, and assign responsible team members to accomplish them. Hold a meeting to walk the team through the AEDG checklist for your project’s climate zone. Clarify specific design goals and prescriptive requirements in the OPR for EAp1: Fundamental Commissioning.
Early access to the AEDG by each team member avoids last-minute changes that can have cascading, and costly, effects across many building systems.
The AEDG prescriptive requirements include:
If your project team is not comfortable following these guidelines, consider switching to Option 1, which gives you more flexibility.
Although Option 2 is generally lower cost during the design phase than energy modeling, the compliance path is top heavy—it requires additional meeting time upfront for key design members.
Provide a copy of the New Buildings Institute Advanced Buildings: Core Performance Guide to each team member. The guide is available to download free from the NBI website. (See Resources.)
The guide provides practical design assistance that can be used throughout the design process.
Walk your team through the project checklist to clarify design goals and prescriptive requirements.
The guide provides an outline for approaching an energy-efficient design, in addition to a list of prescriptive measures. The first of its three sections emphasizes process and team interaction rather than specific building systems or features. Advise the owner to read through the guide in order to understand what is required of the architect and engineers.
Section 1 in the guide focuses on best practices that benefit the project during the pre-design and schematic design stages, such as analyzing alternative designs and writing the owner’s project requirements (OPR).
Section 2 of the Core Performance Guide describes architectural, lighting, and mechanical systems to be included. Section 3 is not required for EAp2 but includes additional opportunities for energy savings that can earn EAc1 points.
The guide mandates that your team develop a minimum of three different design concepts to select from for best energy use.
Though they can be a little daunting at first glance, a majority of the guide’s requirements overlap with other LEED credits, such as EAp1: Fundamental Commissioning, IEQp1: Minimum Indoor Air Quality Performance, and IEQc6.1: Controllability of Systems—Lighting Controls.
This compliance path is top-heavy due to upfront consultant time, but it provides adequate structure to ensure that your project is in compliance with the prerequisite requirements. For some projects it may be less expensive to pursue than Option 1.
The owner should now have finalized the OPR with the support of the architect, as part of the commissioning credits EAp1 and EAc3. The goals identified here will help your team identify energy-reduction and occupant-comfort strategies.
Consider a broad range of energy-efficiency strategies and tools, including passive solar, daylighting, cooling-load reduction, and natural ventilation to reduce heating and cooling loads.
Develop the basis of design (BOD) document in conjunction with your mechanical engineer and architect for EAp1: Fundamental Commissioning, noting key design parameters to help strategize design direction as outlined in the OPR.
The OPR and BOD serve the larger purpose of documenting the owner’s vision and your team’s ideas to meet those goals. The BOD is intended to be a work-in-progress and should be updated at all key milestones in your project. Writing the document gives you an opportunity to capture the owner’s goals, whether just to meet the prerequisite or to achieve points under EAc1.
Confirm that your chosen compliance path is the most appropriate for your project, and make any changes now. Following a review with the design team and owner, ensure that everyone is on board with contracting an energy modeler for Option 1 or meeting all the prescriptive requirements under Options 2 or 3.
Sometimes teams change from Option 1 to Options 2 or 3 very late in the design phase for various reasons including not realizing the cost of energy modeling. Making that change is risky, though: the prescriptive paths are all-or-nothing—you must comply with every item, without exception. Evaluate each requirement and consult with the contractor and estimator to ensure the inclusion of all activities within project management.
To avoid costly, last-minute decisions, develop a comprehensive, component-based cost model as a decision matrix for your project. The model will help establish additional cost requirements for each energy conservation measure. It will also illustrate cost reductions from decreased equipment size, construction rendered unnecessary by energy conservation measures, and reduced architectural provisions for space and equipment access. (See the Documentation Toolkit for an example.)
Use envelope design and passive strategies to reduce the heating and cooling loads prior to detailed design of HVAC systems. Passive strategies can reduce heating and cooling loads, giving the engineer more options, including smaller or innovative systems.
Load reduction requires coordinated efforts by all design members including the architect, lighting designer, interior designer, information-technology manager, and owner.
Involving facilities staff in the design process can further inform key design decisions, helping ensure successful operation and low maintenance costs.
Encourage your design team to brainstorm design innovations and energy-reduction strategies. This provides a communication link among team members so they can make informed decisions.
More energy-efficient HVAC equipment can cost more relative to conventional equipment. However, by reducing heating and cooling loads through good passive design, the mechanical engineer can often reduce the size and cost of the system. Reduced system size can save money through:
Review case studies of similar energy-efficient buildings in the same climate to provide helpful hints for selecting energy-efficiency measures. For example, a building in a heating-dominated climate can often benefit from natural ventilation and free cooling during shoulder seasons. (See Resources for leading industry journals showcasing success stories around the country and internationally.)
The relationship between first costs and operating costs can be complex. For example, more efficient windows will be more expensive, but could reduce the size and cost of mechanical equipment. A more efficient HVAC system may be more expensive, but will reduce operating costs. Play around with variables and different strategies to get the right fit for the building and the owner’s goals as stated in the OPR.
Review and confirm compliance with the mandatory requirements of all the relevant sections of ASHRAE 90.1-2007
Trust your project’s energy modeling task to a mechanical firm with a proven track record in using models as design tools, and experience with your building type.
Contract an energy modeling team for the project. These services may be provided by the mechanical engineering firm on the design team or by an outside consultant. Software used for detailed energy use analysis and submitted for final LEED certification must be accepted by the regulatory authority with jurisdiction, and must comply with paragraph G2.2 of ASHRAE Standard 90.1-2007. Refer to Resources for a list of Department of Energy approved energy-analysis software that may be used for LEED projects.
Design team members, including the architect and mechanical engineer at a minimum, need to work together to identify a percentage improvement goal for project energy use over the ASHRAE 90.1-2007-compliant baseline model. The percentage should be at least 10% to meet the prerequisite.
Plan on initiating energy modeling during the design process, and use it to inform your design—preferably executing several iterations of the design as you improve the modeled energy performance.
Ask the modeling consultant to develop an annual energy-use breakdown—in order to pick the “fattest” targets for energy reduction. A typical energy-use breakdown required for LEED submission and ASHRAE protocol includes:
Identify critical areas in which to reduce loads. For example, in a data center, the plug loads are the largest energy load. Small changes in lighting density might bring down the energy use but represent only a small fraction of annual energy use.
Don't forget that LEED (following ASHRAE) uses energy cost and not straight energy when it compares your design to a base case. That's important because you might choose to use a system that burns natural gas instead of electricity and come out with a lower cost, even though the on-site energy usage in kBtus or kWhs is higher. Generally you have to specify the same fuel in your design case and in the base case, however, so you can't simply switch fuels to show a cost savings
Explore and analyze design alternatives for energy use analyses to compare the cost-effectiveness of your design choices. For example, do you get better overall performance from a better window or from adding a PV panel? Will demand-control ventilation outperform increased ceiling insulation?
Simple, comparative energy analyses of conceptual design forms are useful ways to utilize an energy model at this stage. Sample scenarios include varying the area of east-facing windows and looking at 35% versus 55% glazing. Each scenario can be ranked by absolute energy use to make informed decisions during the design stage.
If your project is using BIM software, the model can be plugged into the energy analysis software to provide quick, real-time results and support better decisions.
Model development should be carried out following the PRM from ASHRAE 90.1-2007, Appendix G, and the LEED 2009 Design and Construction Reference Guide, Table in EAc1. In case of a conflict between ASHRAE and LEED guidelines, follow LEED.
Projects using district energy systems have special requirements. For EAp2, the proposed building must achieve the 10% energy savings without counting the effects of the district generation system. To earn points in EAc1 you can take advantage of the district system’s efficiency, but you have to run the energy model again to claim those benefits (see EAc1 for details).
While you could run the required energy model at the end of the design development phase, simply to demonstrate your prerequisite compliance, you don’t get the most value that way in terms of effort and expense. Instead, do it early in the design phase, and run several versions as you optimize your design. Running the model also gives you an opportunity to make improvements if your project finds itself below the required 10% savings threshold.
The baseline model is the designed building with mechanical systems specified in ASHRAE 90.1-2007, Appendix G, for the specific building type, with a window-to-wall ratio at a maximum of 40%, and minimally code-compliant specifications for the envelope, lighting, and mechanical components. It can be developed as soon as preliminary drawings are completed. The baseline is compared to the design case to provide a percentage of reduction in annual energy use. To avoid any bias from orientation, you need to run the baseline model in each of the four primary directions, and the average serves as your final baseline figure.
The design-case is modeled using the schematic design, orientation, and proposed window-to-wall ratio—¬the model will return design-case annual energy costs. Earn points by demonstrating percentage reductions in annual energy costs from the design to the baseline case. EAp2 is achieved if the design case is 10% lower than the baseline in new construction (or 5% less in existing building renovations).
Provide as much project and design detail to the modeler as possible. A checklist is typically developed by the energy modeler, listing all the construction details of the walls, roof, slabs, windows, mechanical systems, equipment efficiencies, occupancy load, and schedule of operations. Any additional relevant information or design changes should be brought to the modeler’s attention as soon as possible. The more realistic the energy model is, the more accurate the energy use figure, leading to better help with your design.
Invite energy modelers to project meetings. An experienced modeler can often assist in decision-making during design meetings, even without running complete models each time.
All known plug loads must be included in the model. The baseline and design-case models assume identical plug loads. If your project is deliberately attempting to reduce plug loads, demonstrate this by following the exceptional calculation method (ECM), as described in ASHRAE 90.1-2007, G2.5. Incorporate these results in the model to determine energy savings.
For items outside the owner’s control—like lighting layout, fans and pumps—the parameters for the design and baseline models must be identical.
It can take anywhere from a few days to a few weeks to generate meaningful energy modeling results. Schedule the due dates for modeling results so that they can inform your design process.
Review the rate structure from your electrical utility. The format can inform your team of the measures likely to be most effective in reducing energy costs, especially as they vary over season, peak load, and additional charges beyond minimum energy use.
Performing a cost-benefit analysis in conjunction with energy modeling can determine payback times for all the energy strategies, helping the iterative design process.
Using energy modeling only to check compliance after the design stage wastes much of the value of the service, and thus your investment.
The architect and mechanical engineer should carefully read the applicable ASHRAE Advanced Energy Design Guide for office, warehouse, or retail projects, as applicable.
Keep the owner abreast of the design decisions dictated by the standard. Fill in the team-developed checklist, within the climate zone table’s prescribed requirements, with appropriate envelope improvements, system efficiencies, and a configuration that meets the standard requirements.
As a prescriptive path, this option relies heavily on following the requirement checklist, which is used throughout the design process to track progress. To assist design development, provide all critical team members—not limited to the architect, mechanical and electrical engineers, and lighting designer—with a checklist highlighting their appointed tasks.
The architect, mechanical engineer, and lighting designer need to discuss each requirement and its design ramifications. Hold these meetings every six to eight weeks to discuss progress and make sure all requirements are being met.
Confirm that your project team is comfortable with following all the prescribed requirements. If not, switch to Option 1: Whole Building Energy Simulation.
The LEED Online credit form does not specify how to document each prescriptive requirement because they are so different for each project; it only requires a signed confirmation by the MEP for meeting AEDG requirements. You still have to provide documentation. Submit your checklist of requirements, and supporting information for each item, through LEED Online to make your case. If your project fails to meet even one requirement, it will fail to earn the prerequisite, thus jeopardizing LEED certification.
Although energy modeling consultant costs are avoided by this option, additional staff time will be required to document and track compliance status, as compared with conventional projects.
Energy efficiency measures prescribed by the guide can be perceived as additional costs in comparison with conventional projects. However, they are easy to implement and are cost-effective pn the whole.
Become familiar with the Core Performance Guide early in the design phase to know the multiple requirements and all requisite documents.
Note that the guide demands additional time, attention, and integrated process from the design team as compared to conventional projects. It’s not just a list of prescriptive requirements, but a prescribed process for achieving energy efficiency goals. LEED Online documentation requires proof of all steps outlined in Sections 1 and 2, including three conceptual design options and meeting minutes. The project manager, architect, and mechanical engineer should read the complete Core Performance Guide carefully to know beforehand the prescriptive requirements in Sections 1 and 2.
The project manager must take responsibility for ensuring that the requirement checklist is on track.
For Section 3, the design team needs to identify three or more of the listed strategies as possible targets for the project.
Create a checklist of requirements and assign a responsible party to each item.
The Core Performance Guide requires an integrated design contributed by the architect, mechanical and electrical engineers, and lighting designer. The project manager must take responsibility for shepherding and documenting the collaborative process to demonstrate compliance.
A long documentation list can be overwhelming for your team, so create a detailed checklist with tasks delegated to individual team members, allowing each member to focus on assigned tasks. The checklist can function as a status tracking document and, finally, the deliverable for LEED Online.
The architect and engineer, and other project team members, continue to develop a high-performance building envelope with efficient mechanical and lighting systems.
Constant communication and feedback among project team members, owner, and if possible, operational staff, during design development can minimize construction as well as operational costs and keep your project on schedule.
If you change or go through value-engineering on any specifications, such as the solar-heat gain coefficient of glazing, for example, be aware of impacts on mechanical system sizing. Making changes like this might not pay off as much as it first appears.
Consider using building information modeling (BIM) tools to keep design decisions up to date and well documented for all team members.
Schedule delays can be avoided if all team members share their ideas and update documents during the design development process.
The modeler completes the energy analysis of the selected design and system and offers alternative scenarios for discussion. The modeler presents the energy cost reduction results to the team, identifying the LEED threshold achieved.
It’s helpful for the energy modeling report to include a simple payback analysis to assist the owner in making an informed decision on the operational savings of recommended features.
The architect and HVAC engineer should agree on the design, working with the cost estimator and owner.
Demonstrating reductions in non-regulated loads requires a rigorous definition of the baseline case. The loads must be totally equivalent, in terms of functionality, to the proposed design case. For example, reducing the number of computers in the building does not qualify as a legitimate reduction in non-regulated loads. However, the substitution of laptops for desktop computers, and utilization of flat-screen displays instead of CRTs for the same number of computers, may qualify as a reduction.
Residential and hospitality projects that use low-flow showers, lavatories, and kitchen sinks (contributing to WEp1) benefit from lower energy use due to reduced overall demand for hot water. However, for energy-savings calculations, these are considered process loads that must be modeled as identical in baseline and design cases, or you have the choice of demonstrating the savings with ECM for process loads.
Perform daylight calculations in conjunction with energy modeling to balance the potentially competing goals of more daylight versus higher solar-heat gain resulting in high cooling loads.
If your project is pursuing renewable energy, the energy generated is accounted for by using the PRM. These results provide information about whether the energy is contributing to EAc2: Onsite Renewable Energy.
A cost-benefit analysis can help the owner understand the return on investment of big-ticket, energy-conserving equipment that lowers operating energy bills with a quick payback.
Complete at least half of the energy modeling effort by the end of the design development stage. Help the design team to finalize strategy through intensive, early efforts in energy modeling. Once the team has a design direction, the modeler can develop a second model during the construction documents phase for final confirmation.
If pursuing ECM for non-regulated loads, calculate energy saving for each measure separately if you are, for example, installing an energy-efficient elevator instead of a typical one so that the reduction would contribute to total building energy savings. Calculate the anticipated energy use of the typical elevator in kBTUs or kWh. Using the same occupancy load, calculate the energy use of the efficient elevator. Incorporate the savings into design case energy use within the PRM. Refer to the ECM strategy for detailed calculation guidelines.
Ensure that all prescriptive requirements are incorporated into the design by the end of the design development stage.
Revisit the Advanced Energy Design Guides (AEDG) checklist to ensure that the design meets the prescriptive requirements.
The mechanical engineer, lighting consultant, and architect revisit the checklist for an update on the requirements and how they are being integrated into the design. All prescriptive requirements should be specifically incorporated into the design by the end of the design development phase.
The mechanical engineer and architect track the status of each requirement.
While the LEED Online credit form does not require detailed documentation for each Core Performance Guide requirement, it is important that each item be documented as required and reviewed by the rest of the team to confirm compliance, especially as further documentation may be requested by during review. Your design team should work with the owner to identify cost-effective strategies from Section 3 that can be pursued for the project.
Construction documents clearly detail the architectural and mechanical systems that address energy-efficiency strategies.
Confirm that specifications and the bid package integrate all equipment and activities associated with the project.
If the project goes through value engineering, refer to the OPR and BOD to ensure that no key comfort, health, productivity, daylight, or life-cycle cost concerns are sacrificed.
During the budget estimating phase, the project team may decide to remove some energy-saving strategies that have been identified as high-cost items during the value-engineering process. However, it is very important to help the project team understand that these so-called add-ons are actually integral to the building’s market value and the owner’s goals.
Removing an atrium, for example, due to high cost may provide additional saleable floor area, but may also reduce daylight penetration while increasing the lighting and conditioning loads.
Although this prerequisite is a design-phase submittal, it may make sense to submit it, along with EAc1, after construction. Your project could undergo changes during construction that might compel a new run of the energy model to obtain the latest energy-saving information. Waiting until the completion of construction ensures that the actual designed project is reflected in your energy model.
Create a final energy model based completely on construction document drawings—to confirm actual energy savings as compared to ASHRAE 90.1-2007 requirements. An energy model based on the construction documents phase will provide realistic energy-cost savings and corresponding LEED points likely to be earned.
Make sure the results fit the LEED Online credit form requirements. For example, the unmet load hours have to be less than 300 and process loads will raise a red flag if they’re not approximately 25%. If any of the results are off mark, take time to redo the model. Time spent in design saves more later on in the LEED review process.
Finalize all design decisions and confirm that you’ve met all of the prescriptive requirements. Your team must document the checklist with relevant project drawings, including wall sections, specifications, and the MEP drawing layout.
Value engineering and other factors can result in design changes that eliminate certain energy features relevant to the prerequisite. As this compliance path is prescriptive, your project cannot afford to drop even one prescribed item.
Value engineering and other factors can result in design changes that eliminate certain energy features relevant to the credit. As this compliance path is prescriptive, your project cannot afford to drop even one listed item. Although perceived as high-cost, prescriptive requirements lower energy costs during operation and provide a simple payback structure.
The architect and mechanical engineer review the shop drawings to confirm the installation of the selected systems.
The commissioning agent and the contractor conduct functional testing of all mechanical equipment in accordance with EAp1: Fundamental Commissioning and EAc3: Enhanced Commissioning.
Find your Energy Star rating with EPA’s Target Finder tool if your building type is in the database. Input your project location, size, and number of occupants, computers, and kitchen appliances. The target may be a percentage energy-use reduction compared to a code-compliant building, or “anticipated energy use” data from energy model results. Add information about your fuel use and rate, then click to “View Results.” Your Target Finder score should be documented at LEED Online.
Plan for frequent site visits by the mechanical designer and architect during construction and installation to make sure construction meets the design intent and specifications.
Emphasize team interaction and construction involvement when defining the project scope with key design team members. Contractor and designer meetings can help ensure correct construction practices and avoid high change-order costs for the owner.
Subcontractors may attempt to add a premium during the bidding process for any unusual or unknown materials or practices, so inform your construction bidders of any atypical design systems at the pre-bid meeting.
The energy modeler ensures that any final design changes have been incorporated into the updated model.
Upon finalizing of the design, the responsible party or energy modeler completes the LEED Online submittal with building design inputs and a PRM result energy summary.
Although EAp2 is a design phase submittals, it may make sense to submit it (along with EAc1) after construction. Your project could undergo changes during construction that might require a new run of the energy model. Waiting until the completion of construction ensures that your actual designed project is reflected. On the other hand, it gives you less opportunity to respond to questions that might come up during a LEED review.
Include supporting documents like equipment cut sheets, specifications and equipment schedules to demonstrate all energy efficiency measures claimed in the building.
It common for the LEED reviewers to make requests for more information. Go along with the process—it doesn’t mean that you’ve lost the credit. Provide as much information for LEED Online submittal as requested and possible.
The design team completes the LEED Online documentation, signing off on compliance with the applicable AEDG, and writing the narrative report on the design approach and key highlights.
During LEED submission, the project team needs to make an extra effort to support the prerequisite with the completed checklist and the required documents. Although the LEED rating system does not list detailed documentation, it is best practice to send in supporting documents for the prescriptive requirements from the AEDG. The supporting documents should include relevant narratives, wall sections, mechanical drawings, and calculations.
Although the LEED Online sign-off does not include a checklist of AEDG requirements, it assumes that the team member is confirming compliance with all detailed requirements of the guide.
The design team completes the LEED Online credit form, signing off on compliance with the Core Performance Guide, and writing the narrative report on the design approach and key highlights.
During LEED submission, your project team needs to make an extra effort to support the prerequisite with the completed checklist and the required documents. Although not every requirement may be mentioned in the LEED documentation, the supporting documents need to cover all requirements with narratives, wall sections, mechanical drawings, and calculations.
Many of this option’s compliance documents are common to other LEED credits or design documents, thus reducing duplicated efforts.
Develop an operations manual with input from the design team in collaboration with facility management and commissioning agent if pursuing EAc3: Enhanced Commissioning.
The benefit of designing for energy efficiency is realized only during operations and maintenance. Record energy use to confirm that your project is saving energy as anticipated. If you are not pursuing EAc5: Measurement and Verification, you can implement tracking procedures such as reviewing monthly energy bills or on-the-spot metering.
Some energy efficiency features may require special training for operations and maintenance personnel. For example, cogeneration and building automation systems require commissioning and operator training. Consider employing a trained professional to aid in creating operation manuals for specialty items.
Energy-efficiency measures with a higher first cost often provide large savings in energy use and operational energy bills. These credit requirements are directly tied to the benefits of efficient, low-cost operations.
Excerpted from LEED 2009 for New Construction and Major Renovations
To establish the minimum level of energy efficiency for the proposed building and systems to reduce environmental and economic impacts associated with excessive energy use.
Demonstrate a 10% improvement in the proposed building performance rating for new buildings, or a 5% improvement in the proposed building performance rating for major renovations to existing buildings, compared with the baseline building performanceBaseline building performance is the annual energy cost for a building design, used as a baseline for comparison with above-standard design. rating.
Calculate the baseline building performance rating according to the building performance rating method in Appendix G of ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1) using a computer simulation model for the whole building project. Projects outside the U.S. may use a USGBC approved equivalent standard2.
Appendix G of Standard 90.1-2007 requires that the energy analysis done for the building performance rating method include all energy costs associated with the building project. To achieve points using this credit, the proposed design must meet the following criteria:
For the purpose of this analysis, process energy is considered to include, but is not limited to, office and general miscellaneous equipment, computers, elevators and escalators,kitchen cooking and refrigeration, laundry washing and drying, lighting exempt from the lighting power allowance (e.g., lighting integral to medical equipment) and other (e.g., waterfall pumps).
Regulated (non-process) energy includes lighting (for the interior, parking garage, surface parking, façade, or building grounds, etc. except as noted above), heating, ventilation and air conditioning (HVAC) (for space heating, space cooling, fans, pumps, toilet exhaust, parking garage ventilation, kitchen hood exhaust, etc.), and service water heating for domestic or space heating purposes.
Process loads must be identical for both the baseline building performance rating and the proposed building performance rating. However, project teams may follow the exceptional calculation method (ANSI/ASHRAE/IESNA Standard 90.1-2007 G2.5) or USGBC approved equivalent to document measures that reduce process loads. Documentation of process load energy savings must include a list of the assumptions made for both the base and the proposed design, and theoretical or empirical information supporting these assumptions.
Projects in California may use Title 24-2005, Part 6 in place of ANSI/ASHRAE/IESNA Standard 90.1-2007 for Option 1.
Comply with the prescriptive measures of the ASHRAE Advanced Energy Design Guide appropriate to the project scope, outlined below. Project teams must comply with all applicable criteria as established in the Advanced Energy Design Guide for the climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. in which the building is located. Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
The building must meet the following requirements:
Comply with the prescriptive measures identified in the Advanced Buildings™ Core Performance™ Guide developed by the New Buildings Institute. The building must meet the following requirements:
Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
Projects in Brazil that are certified at the “A” level under the Regulation for Energy Efficiency Labeling (PBE Edifica) program for all attributes (Envelope, Lighting, HVAC) achieve this prerequisite. The following building types cannot achieve this prerequisite using this option: Healthcare, Data Centers, Manufacturing Facilities, Warehouses, and Laboratories.
1Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
2 Projects outside the U.S. may use an alternative standard to ANSI/ASHRAE/IESNA Standard 90.1-2007 if it is approved by USGBC as an equivalent standard using the process identified in the LEED 2009 Green Building Design and Construction Global ACP Reference Guide Supplement.
The following pilot alternative compliance path is available for this prerequisite. See the pilot credit library for more information.
EApc95: Alternative Energy Performance Metric ACP
Design the building envelope and systems to meet baseline requirements. Use a computer simulation model to assess the energy performance and identify the most cost-effective energy efficiency measures. Quantify energy performance compared with a baseline building.
If local code has demonstrated quantitative and textual equivalence following, at a minimum, the U.S. Department of Energy (DOE) standard process for commercial energy code determination, then the results of that analysis may be used to correlate local code performance with ANSI/ASHRAE/IESNA Standard 90.1-2007. Details on the DOE process for commercial energy code determination can be found at http://www.energycodes.gov/implement/ determinations_com.stm.
1 Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
2 Projects outside the U.S. may use an alternative standard to ANSI/ASHRAE/IESNA Standard 90.1‐2007 if it is approved by USGBC as an equivalent standard using the process located at www.usgbc.org/leedisglobal
This database shows state-by-state incentives for energy efficiency, renewable energy, and other green building measures. Included in this database are incentives on demand control ventilation, ERVs, and HRVs.
Useful web resource with information on local/regional incentives for energy-efficiency programs.
ACEEE is a nonprofit organization dedicated to advancing energy efficiency through technical and policy assessments; advising policymakers and program managers; collaborating with businesses, public interest groups, and other organizations; and providing education and outreach through conferences, workshops, and publications.
The New Buildings Institute is a nonprofit, public-benefits corporation dedicated to making buildings better for people and the environment. Its mission is to promote energy efficiency in buildings through technology research, guidelines, and codes.
The Building Energy Codes program provides comprehensive resources for states and code users, including news, compliance software, code comparisons, and the Status of State Energy Codes database. The database includes state energy contacts, code status, code history, DOE grants awarded, and construction data. The program is also updating the COMcheck-EZ compliance tool to include ANSI/ASHRAE/IESNA 90.1–2007. This compliance tool includes the prescriptive path and trade-off compliance methods. The software generates appropriate compliance forms as well.
Research center at RPI provides access to a wide range of daylighting resources, case studies, design tools, reports, publications and more.
International association of energy modelers with various national and local chapters.
Non-profit organization aiming at design community to increase collaboration for designing energy efficient buildings.
The Low Impact Hydropower Institute is a non-profit organization and certification body that establishes criteria against which to judge the environmental impacts of hydropower projects in the United States.
The Building Technologies Program (BTP) provides resources for commercial and residential building components, energy modeling tools, building energy codes, and appliance standards including the Buildings Energy Data Book, High Performance Buildings Database and Software Tools Directory.
This website discusses the step-by-step process for energy modeling.
This online resource, supported by Natural Resources Canada, presents energy-efficient technologies, strategies for commercial buildings, and pertinent case studies.
This website is a comprehensive resource for U.S. Department of Energy information on energy efficiency and renewable energy and provides access to energy links and downloadable documents.
Information on cogenerationThe simultaneous production of electric and thermal energy in on-site, distributed energy systems; typically, waste heat from the electricity generation process is recovered and used to heat, cool, or dehumidify building space. Neither generation of electricity without use of the byproduct heat, nor waste-heat recovery from processes other than electricity generation is included in the definition of cogeneration., also called combined heat and power, is available from EPA through the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. Partnership. The CHP Partnership is a voluntary program seeking to reduce the environmental impact of power generation by promoting the use of CHP. The Partnership works closely with energy users, the CHP industry, state and local governments, and other clean energy stakeholders to facilitate the development of new projects and to promote their environmental and economic benefits.
Free download of AHSRAE energy savings guide, use for Option 2.
Research warehouse for strategies and case studies of energy efficiency in buildings.
An online window selection tool with performance characteristics.
This website lays out design process for developing an energy efficient building.
This website discusses ways to improve design for lower energy demand as they relate to the AIA 2030 challenge.
This website includes discussion of design issues, materials and assemblies, window design decisions and case studies.
This site lists multiple web-based and downloadable tools that can be used for energy analyses.
This database is maintainted by the California Energy Commission and lists resources related to energy use and efficiency.
Energy design tools are available to be used for free online or available to download.
This website lists performance characteristics for various envelope materials.
This is an online forum of discussion for energy efficiency, computer model software users.
Target Finder is a goal-setting tool that informs your design team about their project’s energy performance as compared to a national database of projects compiled by the EPA.
This directory provides information on 406 building software tools for evaluating energy efficiency, renewable energy, and sustainability in buildings.
Weather data for more than 2100 locations are available in EnergyPlus weather format.
Weather data for U.S. and Non-U.S. locations in BIN format.
A web-based, free content project by IBPSA-USA to develop an online compendium of the domain of Building Energy Modeling (BEM). The intention is to delineate a cohesive body of knowledge for building energy modeling.
A guide for achieving energy efficiency in new commercial buildings, referenced in the LEED energy credits.
This manual is a strategic guide for planning and implementing energy-saving building upgrades. It provides general methods for reviewing and adjusting system control settings, plus procedures for testing and correcting calibration and operation of system components such as sensors, actuators, and controlled devices.
This document is USGBC’s second (v2.0) major release of guidance for district or campus thermal energy in LEED, and is a unified set of guidance comprising the following an update to the original Version 1.0 guidance released May 2008 for LEED v2.x and the initial release of formal guidance for LEED v2009.
This manual offers guidance to building energy modelers, ensuring technically rigorous and credible assessment of energy performance of commercial and multifamily residential buildings. It provides a streamlined process that can be used with various existing modeling software and systems, across a range of programs.
Chapter 19 is titled, “Energy Estimating and Modeling Methods”. The chapter discusses methods for estimating energy use for two purposes: modeling for building and HVAC system design and associated design optimization (forward modeling), and modeling energy use of existing buildings for establishing baselines and calculating retrofit savings (data-driven modeling).
Required reference document for 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.
Is the Performance Summary Report generated by Trane Trace 700 (Ver 3.0) be enough for the LEED V4 EA credit?
Do I have to still fill out the "v4_Minimum Energy Performance Calculator_August_23_2016.xlsm" ?
Is there any standard energy simulation report format available?
We’ve got a comment for a hotel project that “secondary HVAC systems should be specified in the Baseline building if any of the exception(s) from G3.1.1 are applicable. The non-residential portion of the building appears to be greater than 20,000 square feet and some of the areas of the building are on a different schedule than the hotel.”
In that case, where the project may fall under case (a) of G3.1.1, which system type should the additional system types for non-predominant conditions conform to? Thank you!
Subtract the residential area (hotel) from the total area. Use the remaining area to reenter Table G3.1.1A.
Per 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 10371, we are allowed to claims savings for garage exhaust CO monitoring if we can demonstrate that it's not common practice. I am able to demonstrate that, but my question is how do we calculate those savings? In the past I have used a graph from the ASHRAE Applications Handbook which has three different occupany profiles and estimates savings for each profile. This project is a large mixed-use with office, residential, and a mall. According to the Applications graphs, this type of facility should see about 20% savings with variable speed control. However, the handbook states that this assumes either two-speed control or variable-pitch blades, both of which are much less efficient than VFDA variable frequency drive (VFD) is a device for for controlling the speed of a motor by controlling the frequency of the electrical power supplied to it. VFDs may be used to improve the efficiency of mechanical systems as well as comfort, because they use only as much power as needed, and can be adjusted continuously.. I think a more accurate way to calculate the actual savings is to take the percentages of the profile (ie 60% at 11am and 70% at 3pm) and apply the fan laws to calculate the BHP of the fans for each hour of the day. For example, the BHP at 11am would be 22% of the peak BHP. To be conservative I could use 2.2 as the fan law exponent, which has been approved by local utilities for incentives on previous projects. Thus an hourly calc can be performed and the annual usage can be tabulated. Has anyone tried this approach or a similar one?
Projects pursuing CS certification are allowed to prorate the model based on owner control. Why would they not have a similar path for manufacturing facilities pursuing NC certification?
For example, the "widget maker" consumes 70% of the building's total energy hence the modeler would be able to prorate the model as if 70% were outside the control of the owner.
thank you for any insight you can provide.
CS projects are split between the owner and tenant. It is the fundamental issue of control that makes the difference. If the widget maker builds a building then they control all of the energy use including the process loads and can make decisions that will reduce energy use of that process.
The owner control method for CS was a compromise which was allowed to enable CS projects to ramp up their energy savings over time. In v4 this adjustment went away.
I am working on a large warehouse project, which is an open space with the area of 10,000 square meter. This project is targeting at LEED 2009. As the space is quite big, I just wonder if there are any requirements on creating perimeter zones or not. If treating it as one zone, will it influence the energy results? Has anybody have any experience on this? Many thanks in advance!
The baseline must be modelled as per ASHRAE 90.1-2007 app. G. Therein it tells you how to divide the perimeter into virtual zones. You should do this for the proposed model as well as it is good practice (most of the time, there could be situations where it is not depending on the radiation infall from outdoors). As a good rule of thumb...whereever there is a thermostat, model the zone that thermostat is suposed to control. Again, check the standard...there are some good tips in there.
Thanks for your reply. I read the Table G3.1.7. To my understanding, the HVAC zones have been designed. There are four fan coil heaters distributed in the warehouse. Each air hear has a thermostat. However, I still wonder if it is required to divide the space into four zones as all the internal loads, system etc is the same throughout the warehouse. Many thanks.
To be honest, this is a modelling issue. The thing is that a zone is considered "well mixed" in most programs and does not take into account temperature variation across the zone as would occure in real life. To make sure the thermostats and systems respond "semi-realistically" it is usually a good idea to seperate these as suggested. However, it is situational and geometry together with air movement, both thermally induced and mechanically induced are really what should influence your judgement calls.
Does that make sense?
In a warehouse you would not typically see any perimeter zoning except maybe by the loading docks. All things being equal in each of the 4 areas you could probably combine them into one thermal block without much of an impact on energy use. Combining areas into fewer thermal blocks in my experience is typically done to simplify the model. As Jean suggests this is a judgement call on the part of the modeler. Like all judgement calls you should be able to defend the actions you take as thermodynamically similar enough to only minimally affect the energy use.
I agree and would point out that Marcus says "loading docks", but basically think of other "zones" that may experience other dissimilar thermal loading as well.
For example near a fully glazed wall or near a hot machine. The type of thermostat may also be a consideration. I'm in Europe and just this minute there's a project where we use radiative ceiling elements for heating combined with operative temperature thermostates. Here I would think about hot or cold radiative surfaces as well which may influence the thermostat and drive the heating surface temperatures of the radiative panels. In that case adding additional "virtual" surface to split zones may even negatively effect the thermostat reading, so I need to be careful. At the same time, large spaces (especially high ones) could show some stratification. My software can handle this by using a "non-well mixed" room air model to capture some of these effects without splitting the zone. I've not started this job, but these would be some of the thoughts that would go through my mind to consider.
These kind of impacts start really mattering if the systems are ramping up and down and negatively effect efficiencies which is especially prevelant in radiant systems. Air systems tend to "well mix" better and not suffer from these control symtoms as much.
Thanks for your reply.
This warehouse has very few windows. And I already created separate thermal block for loading bays. I just wonder if it is right to treat the whole open-plan warehouse as one zone and adding the flow rates from each air heater together in the ApacheHVAC.
Yes I understand that stratification may occur in the large space. But just wonder if it is necessary to do separate thermal blocks in this case to be in compliance with LEED requirements. Many thanks!
For LEED Table G3.1-7 tells you what you have to do. The exception for combining blocks will need to apply in order to combine zones into a single block. If all of the exception criteria apply then you can combine them. Jean has been trying to let you know the thinking that needs to go behind the combining of multiple zones into a single block.
I would divide the large open space into core and perimeter zones at a minimum. Since the the spaces are open to one another, I would make the partitions to be 100% hole.
Hello, I have a problem with choosing a basis for my simulation.
I have a building that was designed in 2015 and is about to be build. I need to perform simulations for "Optimize Energy performance" credit...
In LEED 2009 it's said the baseline building should be prepared according to Appendix G Standard 90.1-2007. But there were later also versions 90.1-2010 and 90.1-2013 (The building was designed in 2015!)
Should I then follow direct instructions in manual and prepare baseline model according to 90.1-2007 or rather 90.1-2013, because this is the most appropriate for my building?
Please let me know, in case contact via my mail firstname.lastname@example.org
I would be very thankful for your answers.
The baseline is determined by the version of LEED you register under, not the local code or the year it was designed.
If the project is registered under LEED 2009 then you use 90.1-2007. You can also use 90.1-2010 and there is a alternative point threshold if you do so published in a LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org.. If registered under LEED v4 you use 90.1-2010. I have not yet seen anything about using 90.1-2013.
Thank you very much Marcus!
In my project I am trying to reduce energy consumption, I am using LED lights, high efficient air cooled units (baseline is water cooled chillers).
The building already is underground building but still I can't achieve the required reduction in energy.
Is there an innovative idea which can significantly reduce the energy.
The client is rejecting the use of water cooled chillers.
It is hard to say what strategies will be effective at reducing your energy costs without knowing significantly more detail about the project. Very general questions like this can be difficult to answer in this kind of forum.
ONLY NON-RESIDENCE ALUMINUM FRAME
100 is the standard used to determine U-valueU-value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The greater the U-value, the less efficient the building element is as an insulator. The inverse of (1 divided by) the U-value is the R-value.
200 is the standard used to determine SHGCSolar heat gain coefficient (SHGC): The fraction of solar gain admitted through a window, expressed as a number between 0 and 1.
I am working on a hangar project. It is highly likely that aircraft cooling units (process load) will be added to the project at some point (most likely before initial operation but not decided yet). However they are currently only a placeholder in the design (shown in drawings but blank for info). What are my options for dealing with this in the model for LEED? I understand if they are definitely going in and will operate i should make a reasonable assumption as that is the energy consumption of building but the issue is that as they are not included in the project yet there are a lot of unknowns relating to there size etc. They are pretty big energy hogs so will contribute significantly to receptacle load if they go in which is why its a question worth asking. I don't want to exclude them but then they reviewer picks them up in the drawings and saying they currently aren't included in design isn't accepted as a response.
You should make a reasonable estimate.
We will often defer the submission of EAp2 until the construction phase (assuming you are doing a split submission) to make sure we accurately include any changes made during construction. This might be an option to consider.
I am working on a warehouse project targeting at LEED 2009 certification. I need to fill up the v2009_Minimum Energy Performance Calculator_v06 as part of the submission (if I understand right?). Now I have a few questions regarding this excel sheet. Really need your help, thanks!
1) In the tab of Shading and Fenestration, it requires to fill up the Above grade wall area and vertical glazing area for each orientation. Does anyone know where I can extract these numbers from? I did not find any numbers on the final BPRM report.
2) In the tab of Performance Outputs_1, it showed me quite a few issues, most of which are related to exterior lighting. There is no exterior lighting designed for this project, so I did not apply any exterior lighting for both baseline and proposed models. However it said that 'the baseline/or proposed exterior lighting equivalent full load hours differs by more than 5%, which is unexpected'. Does anyone have any experience in such issue? Many thanks in advance!
You are not required to use it. You can request that GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). change the forms in LEED Online to the older ones or you can simply upload the older forms. Make sure to use the section 1.4 spreadsheet with the v5 of the form. Don't use the v6 of the form and the old section 1.4 tables.
1. Not sure where you get these numbers in IES-VE. The reporting is quite limited so you will have to dig some. I would contact IES-VE.
2. There are problems with some of the issues raised in that section of the spreadsheet. If an issue raised does not seem applicable just enter NA. Equivalent full load hours are the energy use divided by the demand. It is a check used to make sure that the schedules for the operation of electrical equipment appear reasonable.
Many thanks for your quick reply!
Could you please also advise where to download the section 1.4 table with v5? I only found one updated in jan 2014 and unsure of that is the right one. Thanks.
Could you also advise what documents are required to submit as part of EAp2 and EAc1? To my undestanding, it should be the Section 1.4 table and Building Performance report from IES. Is that right? Do I need to submit anything else? such as Energy model? Many thanks.
The January 2014 version is the most recent.
That sounds right to me. IES is pretty weak on reporting especially on the HVAC side so it can be a good idea to show modeling inputs for HVAC through screen captures or other means. This is especially the case if you are doing anything slightly anomalous. Do not submit the model file.
Many thanks for your help!
May I ask why v6 is not preferred in this case? I found that v6 was much more convenient, for example it allowed me to use SI Units. Many thanks!
There is nothing wrong with the v6 form beyond some remaining functional issues. If you use the v6 form use it with the Minimum Energy Performance Calculator. If you use the v5 form use it with the Section 1.4 Tables. The problem is when you mix this up and use the v6 form with the Section 1.4 Tables. In that scenario you will not be providing sufficient information for the review.
The wall and window area by orientation can be obtained by going to ModelIT->Model Report and selecting Above grade glazing % under Section B: Data Assignment.
Because there is so much that you could take a screen shot of to report the HVAC inputs, I generally wait until I get review comments to provide any more detail than what is in the BPRM report or table 1.4. Once there are review comments I can provide screen shots of the particular system they have questions about. After all, the baseline sizing and efficiency requirements are predefined in the baseline prototype systems. I would provide screen shots with explanations of anything out of the ordinary that could cause questions in the review.
I am working on a residential project. The proposed case HVAC system is Water loop 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. with cooling tower and natural gas based condensing boilers. My question is: what will be the baseline system : system 1 Or System 2 of Ashrae 90.1.
That is a hybrid system so a System #1.
As per DES – Performance path option 1, the DES has to be modeled as purchased energy in both baseline and proposed case energy models.
For proposed model, the pumps which are downstream equipmentDownstream equipment consists of all heating or cooling systems, equipment, and controls located within the project building and site associated with transporting thermal energy into heated or cooled spaces. This includes the thermal connection or interface with the district energy system, secondary distribution systems in the building, and terminal units. within the LEED boundary shall be modeled with chilled water meter. So, how to model the pumps for purchased energy in baseline case?
Identical to the proposed since those pumps are not regulated by 90.1-2007 without addenda.
If you follow Addendum ai instead of DES Option 1 the Baseline pumps are defined there.
Thanks Marcus. So for projects which do not have pumps downstream, can we neglect the pumps energy consumption after modeling in base & proposed model.
You don't model the pumps at all if they are not downstream. You treat the chilled water as purchased energy which arrives under sufficient pressure to not require pumps.
Shall we use V4 credit form instead of V6 release currently used on LEED online ? the LEED Release is 2009 ID+C retail.
Our problem is the Additional Interior Lighting Power AllowanceInterior lighting power allowance is the maximum lighting power (in watts) allowed for the interior of a building. on retail project. If we use ASHRAE 91-2007 the Additional LPA is 2.6 W/ft2 (for Retail Area 3 type), but on the LEED online form the the Additional LPA is 1.4 W/ft2 as recommend from ASHRAE 91-2010, that we don't use it for this project. Do you know if we can decide to use the release before because on that the Additional LPA is compliance ASHRAE 91-2007
For LEED 2009 projects you normally use 90.1-2007.
Assuming you are asking the question in the right forum (2009 NC, EAp2), the additional allowance is based on the proposed design. You are allowed to install up to the allowance and not more. The Baseline model reflects the actual design as well. No savings are allowed to be claimed.
You can request to use the older forms (v5) by contacting GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC).. Make sure to use the v5 form with the section 1.4 tables spreadsheet or use the v6 form with the Minimum Energy Performance Calculator. Do not mix the two.
we have two major renovated Building in India
Building 01. No change in building envelope (used the existing wall, floor, window) but changes in whole MEP Design
Building 02. Changes in building envelope & MEP Design
we have some doubts in selecting the basecase building envelope for both buildings
1.Can we consider ASHRAE 90.1 basecase envelope for both buildings instead of existing building envelope (is it wrong)
2.If we consider existing building envelope for building 01 basecase means we need to consider the same wall, floor, window for both cases because there is no changes in building envelope(is it correct)
3.Can we consider the ASHRAE 90.1 basecase envelope for both buildings or Building 01
4.Is it mandatory to consider the existing building envelope for basecase building envelope
5.Is it anything wrong to consider ASHRAE building envelope for major renovated building basecase instead of existing building envelope
Please note that we have advantage of considering existing building envelope for basecase building envelope instead of ASHRAE building envelope
In another major renovation building we don't have existing building details such as (wall, window, floor U value, SHGCSolar heat gain coefficient (SHGC): The fraction of solar gain admitted through a window, expressed as a number between 0 and 1., VLT)
1.Can we consider ASHRAE 90.1 base case envelope instead of existing building envelope
Thanks in Advance
1. Yes, assuming the use of the space did not change significantly. You can't renovate an unconditioned warehouse, for example, into offices and model the existing conditions in the baseline.
3. Yes you could assuming it would be a conservative approach to do so.
4. see #3
5. It does not exactly follow the modeling protocol in Appendix G but there are exception granted such as the results being conservative (lower savings).
You can estimate the details in a variety of ways. Again if the result in conservative you can make the case to use the ASHRAE minimums instead of the existing conditions in the baseline model.
Our project is G+3 factory building and it is a major renovation and we are renovated wall, window, HVAC equipment
and we consider ASHRAE 90.1.2007 Building envelope for base case & renovated building envelope for proposed case
now the LEED reviewer ask to consider the existing building envelope before renovation for basecase and renovated building envelope for proposed case
1. What is the wrong in considering the ASHRAE 90.1.2007 building envelope for Basecase
(Additionally we have more saving in HVAC or considering existing building envelope before renovation for basecase but we don't need that advantage )
2.please advice how to address below review command for the above situation
"it does not appear that the existing envelope conditions prior to retrofit were modeled consistent with the requirements
of ASHRAE 90.1-2007 Table G3.1#5(Baseline)(f). For all envelope assemblies located in spaces that were conditioned prior to retrofit,
model the Baseline Case envelope U-factors, SHGCs, and F-factors using the existing conditions prior to retrofit.
Ensure that separate reports are provided for the existing renovation versus new construction envelope assemblies
in the Table 1.4 spreadsheet for both the Baseline and Proposed Case and clearly identify the existing assemblies
where energy efficient renovations have been made."
As long as you can make the case that the results are conservative (less savings) the reviewer should accept it.
Hi. As per Section 5c of Table G3.1 of ASHRAE 90.1-2007, “Vertical fenestration areas for new buildings and additions shall equal that in in the proposed design or 40% of gross above-grade wall area..”. The question is how about if the opaque wall (no window) is totally covered with tinted glass, is it necessary to comply with this Section? Please advice. Thank you.
An opaque wall covered in glass is a wall, not a window. All projects must comply.
A building that is being certificate under LEED 2009 will be built in a campus with a dedicated District Energy System (DES) based on a combined heat and power plant (CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source.). This DES is working for more than 5 years, serving several other buildings that started its activity along with the DES.
LEED Guidance for this case (Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 – Design & Construction, August 2010 – APPENDIX D) states that CHP electricity shall be allocated to the Proposed Building in the proportion of heat used by it. The question is how to calculate the proportion of heat that the new building will use (please note that historic data from the DES only accounts for the existing buildings only). Our proposal is:
1) If the DES system has capacity to feed the 100% of the new building heating needs (calculated by energy simulation), then we will make the calculation assuming that 100% of the proposed building heating needs will be fed by the DES. Heating energy use of the other buildings will remain the same;
2) If the DES system has not capacity to feed 100% of the new building heating needs (calculated by energy simulation), then we will make the calculation assuming that the proposed building will use all the capacity of the DES that is now available. DES heating energy supply to the existing buildings will remain unchanged.
Do you agree with this option ?
Please help us in solving the Errors in the Minimum Energy Performance Calculator.
Project Registered under => LEED NC BD+C -v3 (2009)
• Macros are not getting enabled
• Shading & Fenestration Tab => Under Baseline case the values namely ‘SHGC’ are not getting auto populated.
• Additional rows cannot be added in the Lighting Tab
• In Lighting tab - if we select Building Area method, it is auto updating values with Space by Space method
• Lighting tab => under Tradable surface the Allowable :LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. is showing as 0.13 instead of 0.15 (as per ASHRAE 90.1 -2007)
• General HVAC & Air Side HVAc Tabs - errors are being noticed
Might want to send these directly to USGBC - usgbc.org/contactus
I am modeling a 50,000 sf college cafeteria. The campus central plant boiler will provide steam to the cafeteria through a utility tunnel at basement level. Inside the basement, steam will be passed through a shell and tube heat exchanger to provide heat to the building hot water loop, as well as provide heating as needed in the condenser water loop via a direct steam injection tank and the SHW loop via a steam injection tank.
Energy Plus 8.5 has a steam boiler component with associated piping, steam traps, condensate pumps, and steam-to-air coil components. It does not currently support a steam-to-water heat exchanger or steam injection tank components. The available heat exchanger objects are for plant hydronic fluids only. The shell and tube heat exchanger will have an efficiency loss, while the direct steam injection tanks have no process loss (all energy in the steam heats the water) but do have tank losses. Since I can't model the system directly, I'm looking for suggested work-arounds. Could this system be modeled as district hot water system instead? Assuming a representative heat loss for the three steam components could be estimated, could that factor be applied to the district hot water system energy use to provide an adjusted district heat use? The same factor would be applied to the Baseline model output, assuming we use Addendum ai, G188.8.131.52.1, Purchased Heat Only.
You might want to look at the District Energy Systems v2 document as another option for modeling the district system.
Under ai or DESv2 Option 1 you could model the hot water system in the building and factor the efficiency of the heat exchanger in the determination of the energy rate for the steam.
Thank you for your prompt reply. DESv2 Option 1 will not be viable for this project because of the point limitations. Would Option 2 work? Thank you!
Potentially but you would need to model all the upstream equipmentUpstream equipment consists of all heating or cooling systems, equipment, and controls that are associated with a district energy system but are not part of the project building's thermal connection or do not interface with the district energy system. It includes the central energy plant and all transmission and distribution equipment associated with transporting the thermal energy to the project building and site..
A quick request for clarification.
Is 90.1-2007 Addenum ai, if used under a LEED 2009 NC project, have the EAc1 point restrictions similar to DESv2 Option 1?
Secondly, if using DESv2 Option 2, and modeling the upstream equipmentUpstream equipment consists of all heating or cooling systems, equipment, and controls that are associated with a district energy system but are not part of the project building's thermal connection or do not interface with the district energy system. It includes the central energy plant and all transmission and distribution equipment associated with transporting the thermal energy to the project building and site., can the steam system be modeled as a hot water system with an efficiency factor for the steam-to-water energy conversion?
No it does not have the point restrictions.
Maybe. You would need to demonstrate that there would be equivalency in energy use/cost and provide a thorough justification for doing so.
I am modeling a 50,000 sf college cafeteria that has a basement, a main floor and a mezzanine. A portion of the basement is part of the cafeteria. About 11,000 sf of the basement has been reserved as a future office space that will not be designed or fitted out until a later date and is not part of the design team's scope except as a core and shell space. It will have its own entrance and the using entity will be a department of the college. The cafeteria building will be served by district fossil fuel steam heat, and a cooling tower with condenser loop will serve a number of water-source heat pumps for cooling and heating. The capacities of the heating and cooling loops have been sized to accommodate the future office space loads. The office space does have a separate mechanical/electrical room. The delivery portion of the HVAC system has not been designed, but I think it is unlikely to be designed with a system that does not tie into the systems that will serve the cafeteria.
My question arises from reviewing ASHRAE 90.1-2007 Appendix G, Table G3.1 Section 10, as well a few of the posts on this forum. Since the future office space HVAC is not fully designed as part of the project scope, but is within the boundaries of the LEED project, I believe I need to model it as a fully occupied space (according to what I'm reading in forum posts). Since the HVAC system is not fully designed, it doesn't seem to fit exactly within Section 10b. But since the capacities of the cafeteria HVAC system will, by design, accommodate the future office space, the situation doesn't seem to fit Sections 10c and 10d where no heating system or no cooling system has been specified. Can I autosize water-source heat pumps, similar to others in the building, tied into the heating and cooling loops, and use this as a Proposed Design for the office space? In turn the exact same system(s) would be used In the Baseline model.
You do need to model it as fully occupied. You have the following options when modeling the Proposed system.
a. The default 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. system modeled in the Baseline case; the Proposed case modeled with any Dedicated Outside Air Handlers as designed and installed within the base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, etc. scope of work, plus a conservative estimate of the fan power and system efficiency for the water source heat pumps. Note: The conservative estimate of fan power and system efficiency for the water source heat pumps may be the worst-case values from manufacturers (Watts / cfm and EER), or the worst-case fan power and efficiency used in the projects in the past five years, or the tenant lease agreement that specifies the worst-case values. ECMEnergy conservation measures are installations or modifications of equipment or systems intended to reduce energy use and costs. motors are not allowed unless included within the tenant lease agreement.
b. The default VAV system to be modeled in both the Baseline and Proposed case, with the only energy efficiency measures being cooling tower controls and condenser pump power.
c. The default VAV system to be modeled in the Baseline case; the Proposed case to be modeled with water source heat pumps having constant volume fans at ASHRAE 90.1 Appendix G default fan power and system efficiency.
The building size is mandating to model the baseline with a water cooled chiller and I will compare the baseline with the design which is using HVAC that is (air cooled chiller + ice storage efficiency 30%+ diversity).
when I compared the results of the energy model between the total baseline energy consumption and the total energy consumption of the design , I found that I achieved 12% reduction (fulfilled the prerequisite requirement).
my questions are:
1. Is it accepted to model the design with the energy of HVAC considering air cooled chillers + diversity + ice storage
2. Should I be prepared to provide any evidence or clue on this HVAC scenario
1. If that is how it is designed then yes. Always model the Proposed as designed.
2. The mechanical schedules should be provided to verify that the project has been modeled as designed.
I am modeling a cooling tower the fan meets the requirement of Appendix G, but I am not sure what is the fan power should be used for the baseline, Should I use the same as proposed model fan power? or there is a calculation for that?
Minimum 38.2 gpm/hp (maximum 0.0262 hp/gpm or 19.5 W/gpm) per Table 6.8.1G
the building size is mandating to model the baseline with a water cooled chiller and I will compare the baseline with the design which is using HVAC that is (air cooled chiller + ice storage + diversity).
I have seen this point tackled in many comments earlier but we still have some doubts. We have a residential building of 16 floors which sits on a podium of 3 floors. Our issues are as follows:
1. Lighting Power Density
Our proposed design consists of complete lighting layout which has separate wiring for lighting including distribution board and separate power wiring to wall receptacle fixtures. We want to use space by space method by considering lighting of 12 W/m² for baseline bedroom by selecting Hotel/Motel Guest Rooms from Table 9.6.1 and12W/m² living room including kitchen as Dormitory Living Quarters.
a. Is the above approach fine as building plans are completely designed or do we need to include receptacle load as per Energy Star Multi Family High Rise Program document? (essentially what approach is agreeable by LEED)
b. Is it necessary to consider lighting irrespective of approach to only operate 2-3 hours per day or is it only for cases where LEED approach per 1712 is adopted?
2. Corridors, electrical, IT closet rooms located on typical residential floors are considered as non-residential conditioned spaces and system type selected is system 8. We also read comments from Marcus earlier which consider corridors in residential spaces as they only serve apartments.
a. Is our conservative approach understandable by selecting an efficient baseline system and hence improving baseline performance ?
b. IT closet and electrical rooms on each typical floor have normally high process load and they are located on each floor (for our case 16 floors). If above approach is considered ok, then our IT & electrical rooms will fall under system 4 due to high process load but if above approach is not ok, then what space category shall be selected for IT & electrical rooms including baseline system type and lighting?
1a. No Hotel/Motel Guest rooms cannot be used for multi-family residential buildings. 90.1 does not regulate the lighting in these buildings so you have to use the Energy Star multi-family simulation methodology.
1b. You have to use the allowable lighting schedule unless you can prove that that schedule does not apply to your situation.
2. For LEED you can do it either way. In my opinion the corridors are clearly residential as they only really serve a residential function.
2a. That could be justification for modeling it the way you suggest.
2b. Electrical closets are Electrical/Mechanical spaces. They typically do not contain much process energy loads as the "heat" from the electrical equipment is not usually included in the models. They often do not contain any separate space conditioning equipment. If they do then you might be able to justify a separate HVAC system. IT closets may contain some process loads. Again if they have separate space conditioning equipment installed then you could probably justify a separate baseline system.
Hi, I have some fans In my building which operate to circulate air. They are low speed when occupied and then ramp up to full speed with Temperature goes above 80F. Should these fans be part of the HVAC or process/receptacle energy (like ceiling fans would be).
It seems that the system can control the indoor temperature, cannot it?
If it can control it, it's a HVAC system.
Thanks, it can control dry resultant temperature (what the occupants feel) but not overall air temperature of the space as its just circulating the air (mixing it up, increasing air volumes).
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