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 22.214.171.124c, a manual control device would be sufficient to comply with mandatory provisions.
Submitting these forms is not common; however, it can be beneficial if you are applying for any exceptions.
Use the building area method.
Although there is no formal list of approved simulation tools, there are a few requirements per G2.2.1, including the ability of the program to provide hourly simulation for 8760 hours per year, and model ten or more thermal zones, which PHPP does not meet.
The automated Trace 700 report provides less information than is requested by the Section 1.4 tables spreadsheet. The Section 1.4 tables spreadsheet must be completed.
Assign HVAC systems as per Appendix-G and Section 6 but set thermostatic setpointsSetpoints are normal operating ranges for building systems and indoor environmental quality. When the building systems are outside of their normal operating range, action is taken by the building operator or automation system. out of range so that systems never turn on.
If it is only used for backup and not for regular use such as peak shaving—no.
SHGC is not a mandatory provision so it is available for trade-off and can be higher than the baseline.
You generally wouldn't need to upload any documentation, but particularly for a non-U.S. project, it may help to provide a short narrative about what they are based on.
Discuss your project’s energy performance objectives, along with how those are shaping design decisions, with the owner. Record energy targets in the Owners Project Requirements (OPR) for the commissioning credits EAp1 and EAc3.
You won’t earn this prerequisite by accident. The energy efficiency requirements here are typically much more stringent than local codes, so plan on giving it special attention with your team, including leadership from the owner.
Consider stating goals in terms of minimum efficiency levels and specific payback periods. For example: “Our goal is to exceed a 20% reduction from ASHRAE 90.1, with all efficiency measures having a payback period of 10 years or less.”
Develop a precedent for energy targets by conducting research on similar building types and using the EPA’s Target Finder program. (See Resources.)
For Option 1 only, you will need to comply with the mandatory requirements of ASHRAE 90.1-2007, to bring your project to the minimum level of performance. The ASHRAE 90.1-2007 User’s Manual is a great resource, with illustrated examples of solutions for meeting the requirements.
ASHRAE 90.1-2007 has some additional requirements compared with 2004. Read through the standard for a complete update. The following are some samples.
The prerequisite’s energy-reduction target of 10% is not common practice and is considered beyond code compliance.
Indirect sunlight delievered through clerestories like this helps reduce lighting loads as well as cooling loads. Photo – YRG Sustainability, Project – Cooper Union, New York A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective. Start with building orientation and passive design features first when looking for energy efficiency. Also look at envelope design, such as energy-efficient windows, walls and roof, before looking at HVAC and plug loads. HVAC may also be a good place to improve performance with more efficient equipment, but first reducing loads with smaller equipment can lead to even greater operational and upfront savings. A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective.
Don’t plan on using onsite renewable energy generation (see EAc2) to make your building energy-efficient. It is almost always more cost-effective to make an efficient building, and then to add renewables like photovoltaics as the “icing” on the cake.
Some rules of thumb to reduce energy use are:
Find the best credit compliance path based on your building type and energy-efficiency targets. Use the following considerations, noting that some projects are more suited to a prescriptive approach than others.
Option 1: Whole Building Energy Simulation requires estimating the energy use of the whole building over a calendar year, using methodology established by ASHRAE 90.1-2007, Appendix G. Option 1 establishes a computer model of the building’s architectural design and all mechanical, electrical, domestic hot water, plug load, and other energy-consuming systems and devices. The model incorporates the occupancy load and a schedule representing projected usage in order to predict energy use. This compliance path does not prescribe any technology or strategy, but requires a minimum reduction in total energy cost of 10% (5% for an existing building), compared to a baseline building with the same form and design but using systems compliant with ASHRAE 90.1-2007. You can earn additional LEED points through EAc1 for cost reductions of 12% and greater (8% for existing buildings).
Option 2: Prescriptive Compliance Path: ASHRAE Advanced Energy Design Guide refers to design guides published by ASHRAE for office, school, warehouse, and retail projects. These guides outline strategies to reduce energy use by 30% from ASHRAE 90.1-2001 levels, or an amount equivalent to a 10%–14% reduction from the ASHRAE 90.1-2007 standard. If you choose this compliance path, become familiar with the list of prescriptive requirements and commit to meeting them. (See the AEDG checklist in the Documentation Toolkit.)
Option 3: Prescriptive Compliance Path: Advanced Buildings Core Performance Guide is another, more basic prescriptive path. It’s a good option if your project is smaller than 100,000 ft2, cannot pursue Option 2 (because there is not an ASHRAE guide for the building type), is not a healthcare facility, lab, or warehouse—or you would rather not commit to the energy modeling required for Option 1. Your project can be of any other building type (such as office or retail). To meet the prerequisite, you must comply with all requirements within Sections 1 and 2 of the guide. If you choose this path, become familiar with the list of activities and requirements and commit to meeting them. (See Resources for a link to the Core Performance Guide and the Documentation Toolkit for the checklist of prescriptive items.)
EAc1: Optimize Energy Performance uses the same structure of Options 1–3, so it makes sense to think about the credit and the prerequisite together when making your choice. In EAc1, Option 1 offers the potential for far more points than Options 2 and 3, so if you see your project as a likely candidate for earning those points, Option 1 may be best.
Hotels, multifamily residential, and unconventional commercial buildings may not be eligible for either Option 2 or Option 3, because the prescriptive guidance of these paths was not intended for them. Complex projects, unconventional building types, off-grid projects, or those with high energy-reduction goals are better off pursuing Option 1, which provides the opportunity to explore more flexible and innovative efficiency strategies and to trade off high-energy uses for lower ones.
If your project combines new construction and existing building renovation then whatever portion contains more than 50% of the floor area would determine the energy thresholds.
Options 2 and 3 are suitable for small, conventional building types that may not have as much to gain from detailed energy modeling with Option 1.
Meeting the prescriptive requirements of Options 2 and 3 is not common practice and requires a high degree of attention to detail by your project team. (See the Documentation Toolkit for the Core Performance Guide Checklist.) These paths are more straightforward than Option 1, but don’t think of them as easy.
Options 2 and 3 require additional consultant time from architects and MEP engineers over typical design commitment, which means higher upfront costs.
Option 1 references the mandatory requirements of ASHRAE 90.1-2007, which are more stringent than earlier LEED rating systems that referred to ASHRAE 90.1-2004.
Option 1 energy simulation provides monthly and annual operating energy use and cost breakdowns. You can complete multiple iterations, refining energy-efficiency strategies each time. Payback periods can be quickly computed for efficiency strategies using their additional first costs. A building’s life is assumed to be 60 years. A payback period of five years is considered a very good choice, and 10 years is typically considered reasonable. Consult the OPR for your owners’ goals while selecting your efficiency strategies.
Option 1 energy simulation often requires hiring an energy modeling consultant, adding a cost (although this ranges, it is typically on the order of $0.10–$0.50/ft2 depending on the complexity). However, these fees produce high value in terms of design and decision-making assistance, and especially for complex or larger projects can be well worth the investment.
All compliance path options may require both the architectural and engineering teams to take some time in addition to project management to review the prescriptive checklists, fill out the LEED Online credit form, and develop the compliance document.
The architect, mechanical engineer, and lighting designer need to familiarize themselves and confirm compliance with the mandatory requirements of ASHRAE 90.1-2007, sections 5–9.
Use simple computer tools like SketchUp and Green Building Studio that are now available with energy analysis plug-ins to generate a first-order estimate of building energy use within a climate context and to identify a design direction. Note that you may need to refer to different software may not be the one used to develop complete the whole building energy simulations necessary for LEED certification.
Energy modeling can inform your project team from the start of design. Early on, review site climate data—such as temperature, humidity and wind, available from most energy software—as a team. Evaluate the site context and the microclimate, noting the effects of neighboring buildings, bodies of water, and vegetation. Estimate the distribution of energy across major end uses (such as space heating and cooling, lighting, plug loads, hot water, and any additional energy uses), targeting high-energy-use areas to focus on during design.
Use a preliminary energy use breakdown like this one to identify target areas for energy savings.Perform preliminary energy modeling in advance of the schematic design phase kick-off meeting or design charrette. The energy use breakdown can help identify targets for energy savings and point toward possible alternatives.
For existing buildings, the baseline energy model can reflect the pre-renovation features like rather than a minimally ASHRAE-compliant building. This will help you achieve additional savings in comparison with the baseline.
Projects generating renewable energy onsite should use Option 1 to best demonstrate EAp2 compliance and maximize points under EAc1. Other options are possible but won’t provide as much benefit. Like any other project, model the baseline case as a system compliant with ASHRAE 90.1-2007, using grid-connected electricity, and the design case is an “as-designed” system also using grid-connected electricity. You then plug in 100% onsite renewable energy in the final energy-cost comparison table, as required by the performance rating method (PRM) or the modeling protocol of ASHRRAE 90.1 2007, Appendix G. (Refer to the sample PRM tables in the Documentation Toolkit for taking account of onsite renewable energy.
LEED divides energy-using systems into two categories:
The energy model itself will not account for any change in plug loads from the baseline case, even if your project is making a conscious effort to purchase Energy Star or other efficient equipment. Any improvement made in plug loads must be documented separately, using the exceptional calculation methodology (ECM), as described in ASHRAE 90.1-2007. These calculations determine the design case energy cost compared to the baseline case. They are included in the performance rating method (PRM) table or directly in the baseline and design case model.
Besides energy modeling, you may need to use the exceptional calculation methodology (ECM) when any of the following situations occur:
Some energy-modeling software tools have a daylight-modeling capability. Using the same model for both energy and IEQc8.1: Daylight and Views—Daylight can greatly reduce the cost of your modeling efforts.
Provide a copy of the AEDG for office, retail, or warehouse, as applicable, to each team member as everyone, including the architect, mechanical and electrical engineers, lighting designer, and commissioning agents, are responsible for ensuring compliance. These are available to download free from the ASHRAE website. (See Resources.)
Find your climate zone before attempting to meet any detailed prescriptive requirements. Climate zones vary by county, so be sure to select the right one. (See the Documentation Toolkit for a list of climate zones by county.)
Develop a checklist of all requirements, and assign responsible team members to accomplish them. Hold a meeting to walk the team through the AEDG checklist for your project’s climate zone. Clarify specific design goals and prescriptive requirements in the OPR for EAp1: Fundamental Commissioning.
Early access to the AEDG by each team member avoids last-minute changes that can have cascading, and costly, effects across many building systems.
The AEDG prescriptive requirements include:
If your project team is not comfortable following these guidelines, consider switching to Option 1, which gives you more flexibility.
Although Option 2 is generally lower cost during the design phase than energy modeling, the compliance path is top heavy—it requires additional meeting time upfront for key design members.
Provide a copy of the New Buildings Institute Advanced Buildings: Core Performance Guide to each team member. The guide is available to download free from the NBI website. (See Resources.)
The guide provides practical design assistance that can be used throughout the design process.
Walk your team through the project checklist to clarify design goals and prescriptive requirements.
The guide provides an outline for approaching an energy-efficient design, in addition to a list of prescriptive measures. The first of its three sections emphasizes process and team interaction rather than specific building systems or features. Advise the owner to read through the guide in order to understand what is required of the architect and engineers.
Section 1 in the guide focuses on best practices that benefit the project during the pre-design and schematic design stages, such as analyzing alternative designs and writing the owner’s project requirements (OPR).
Section 2 of the Core Performance Guide describes architectural, lighting, and mechanical systems to be included. Section 3 is not required for EAp2 but includes additional opportunities for energy savings that can earn EAc1 points.
The guide mandates that your team develop a minimum of three different design concepts to select from for best energy use.
Though they can be a little daunting at first glance, a majority of the guide’s requirements overlap with other LEED credits, such as EAp1: Fundamental Commissioning, IEQp1: Minimum Indoor Air Quality Performance, and IEQc6.1: Controllability of Systems—Lighting Controls.
This compliance path is top-heavy due to upfront consultant time, but it provides adequate structure to ensure that your project is in compliance with the prerequisite requirements. For some projects it may be less expensive to pursue than Option 1.
The owner should now have finalized the OPR with the support of the architect, as part of the commissioning credits EAp1 and EAc3. The goals identified here will help your team identify energy-reduction and occupant-comfort strategies.
Consider a broad range of energy-efficiency strategies and tools, including passive solar, daylighting, cooling-load reduction, and natural ventilation to reduce heating and cooling loads.
Develop the basis of design (BOD) document in conjunction with your mechanical engineer and architect for EAp1: Fundamental Commissioning, noting key design parameters to help strategize design direction as outlined in the OPR.
The OPR and BOD serve the larger purpose of documenting the owner’s vision and your team’s ideas to meet those goals. The BOD is intended to be a work-in-progress and should be updated at all key milestones in your project. Writing the document gives you an opportunity to capture the owner’s goals, whether just to meet the prerequisite or to achieve points under EAc1.
Confirm that your chosen compliance path is the most appropriate for your project, and make any changes now. Following a review with the design team and owner, ensure that everyone is on board with contracting an energy modeler for Option 1 or meeting all the prescriptive requirements under Options 2 or 3.
Sometimes teams change from Option 1 to Options 2 or 3 very late in the design phase for various reasons including not realizing the cost of energy modeling. Making that change is risky, though: the prescriptive paths are all-or-nothing—you must comply with every item, without exception. Evaluate each requirement and consult with the contractor and estimator to ensure the inclusion of all activities within project management.
To avoid costly, last-minute decisions, develop a comprehensive, component-based cost model as a decision matrix for your project. The model will help establish additional cost requirements for each energy conservation measure. It will also illustrate cost reductions from decreased equipment size, construction rendered unnecessary by energy conservation measures, and reduced architectural provisions for space and equipment access. (See the Documentation Toolkit for an example.)
Use envelope design and passive strategies to reduce the heating and cooling loads prior to detailed design of HVAC systems. Passive strategies can reduce heating and cooling loads, giving the engineer more options, including smaller or innovative systems.
Load reduction requires coordinated efforts by all design members including the architect, lighting designer, interior designer, information-technology manager, and owner.
Involving facilities staff in the design process can further inform key design decisions, helping ensure successful operation and low maintenance costs.
Encourage your design team to brainstorm design innovations and energy-reduction strategies. This provides a communication link among team members so they can make informed decisions.
More energy-efficient HVAC equipment can cost more relative to conventional equipment. However, by reducing heating and cooling loads through good passive design, the mechanical engineer can often reduce the size and cost of the system. Reduced system size can save money through:
Review case studies of similar energy-efficient buildings in the same climate to provide helpful hints for selecting energy-efficiency measures. For example, a building in a heating-dominated climate can often benefit from natural ventilation and free cooling during shoulder seasons. (See Resources for leading industry journals showcasing success stories around the country and internationally.)
The relationship between first costs and operating costs can be complex. For example, more efficient windows will be more expensive, but could reduce the size and cost of mechanical equipment. A more efficient HVAC system may be more expensive, but will reduce operating costs. Play around with variables and different strategies to get the right fit for the building and the owner’s goals as stated in the OPR.
Review and confirm compliance with the mandatory requirements of all the relevant sections of ASHRAE 90.1-2007
Trust your project’s energy modeling task to a mechanical firm with a proven track record in using models as design tools, and experience with your building type.
Contract an energy modeling team for the project. These services may be provided by the mechanical engineering firm on the design team or by an outside consultant. Software used for detailed energy use analysis and submitted for final LEED certification must be accepted by the regulatory authority with jurisdiction, and must comply with paragraph G2.2 of ASHRAE Standard 90.1-2007. Refer to Resources for a list of Department of Energy approved energy-analysis software that may be used for LEED projects.
Design team members, including the architect and mechanical engineer at a minimum, need to work together to identify a percentage improvement goal for project energy use over the ASHRAE 90.1-2007-compliant baseline model. The percentage should be at least 10% to meet the prerequisite.
Plan on initiating energy modeling during the design process, and use it to inform your design—preferably executing several iterations of the design as you improve the modeled energy performance.
Ask the modeling consultant to develop an annual energy-use breakdown—in order to pick the “fattest” targets for energy reduction. A typical energy-use breakdown required for LEED submission and ASHRAE protocol includes:
Identify critical areas in which to reduce loads. For example, in a data center, the plug loads are the largest energy load. Small changes in lighting density might bring down the energy use but represent only a small fraction of annual energy use.
Don't forget that LEED (following ASHRAE) uses energy cost and not straight energy when it compares your design to a base case. That's important because you might choose to use a system that burns natural gas instead of electricity and come out with a lower cost, even though the on-site energy usage in kBtus or kWhs is higher. Generally you have to specify the same fuel in your design case and in the base case, however, so you can't simply switch fuels to show a cost savings
Explore and analyze design alternatives for energy use analyses to compare the cost-effectiveness of your design choices. For example, do you get better overall performance from a better window or from adding a PV panel? Will demand-control ventilation outperform increased ceiling insulation?
Simple, comparative energy analyses of conceptual design forms are useful ways to utilize an energy model at this stage. Sample scenarios include varying the area of east-facing windows and looking at 35% versus 55% glazing. Each scenario can be ranked by absolute energy use to make informed decisions during the design stage.
If your project is using BIM software, the model can be plugged into the energy analysis software to provide quick, real-time results and support better decisions.
Model development should be carried out following the PRM from ASHRAE 90.1-2007, Appendix G, and the LEED 2009 Design and Construction Reference Guide, Table in EAc1. In case of a conflict between ASHRAE and LEED guidelines, follow LEED.
Projects using district energy systems have special requirements. For EAp2, the proposed building must achieve the 10% energy savings without counting the effects of the district generation system. To earn points in EAc1 you can take advantage of the district system’s efficiency, but you have to run the energy model again to claim those benefits (see EAc1 for details).
While you could run the required energy model at the end of the design development phase, simply to demonstrate your prerequisite compliance, you don’t get the most value that way in terms of effort and expense. Instead, do it early in the design phase, and run several versions as you optimize your design. Running the model also gives you an opportunity to make improvements if your project finds itself below the required 10% savings threshold.
The baseline model is the designed building with mechanical systems specified in ASHRAE 90.1-2007, Appendix G, for the specific building type, with a window-to-wall ratio at a maximum of 40%, and minimally code-compliant specifications for the envelope, lighting, and mechanical components. It can be developed as soon as preliminary drawings are completed. The baseline is compared to the design case to provide a percentage of reduction in annual energy use. To avoid any bias from orientation, you need to run the baseline model in each of the four primary directions, and the average serves as your final baseline figure.
The design-case is modeled using the schematic design, orientation, and proposed window-to-wall ratio—¬the model will return design-case annual energy costs. Earn points by demonstrating percentage reductions in annual energy costs from the design to the baseline case. EAp2 is achieved if the design case is 10% lower than the baseline in new construction (or 5% less in existing building renovations).
Provide as much project and design detail to the modeler as possible. A checklist is typically developed by the energy modeler, listing all the construction details of the walls, roof, slabs, windows, mechanical systems, equipment efficiencies, occupancy load, and schedule of operations. Any additional relevant information or design changes should be brought to the modeler’s attention as soon as possible. The more realistic the energy model is, the more accurate the energy use figure, leading to better help with your design.
Invite energy modelers to project meetings. An experienced modeler can often assist in decision-making during design meetings, even without running complete models each time.
All known plug loads must be included in the model. The baseline and design-case models assume identical plug loads. If your project is deliberately attempting to reduce plug loads, demonstrate this by following the exceptional calculation method (ECM), as described in ASHRAE 90.1-2007, G2.5. Incorporate these results in the model to determine energy savings.
For items outside the owner’s control—like lighting layout, fans and pumps—the parameters for the design and baseline models must be identical.
It can take anywhere from a few days to a few weeks to generate meaningful energy modeling results. Schedule the due dates for modeling results so that they can inform your design process.
Review the rate structure from your electrical utility. The format can inform your team of the measures likely to be most effective in reducing energy costs, especially as they vary over season, peak load, and additional charges beyond minimum energy use.
Performing a cost-benefit analysis in conjunction with energy modeling can determine payback times for all the energy strategies, helping the iterative design process.
Using energy modeling only to check compliance after the design stage wastes much of the value of the service, and thus your investment.
The architect and mechanical engineer should carefully read the applicable ASHRAE Advanced Energy Design Guide for office, warehouse, or retail projects, as applicable.
Keep the owner abreast of the design decisions dictated by the standard. Fill in the team-developed checklist, within the climate zone table’s prescribed requirements, with appropriate envelope improvements, system efficiencies, and a configuration that meets the standard requirements.
As a prescriptive path, this option relies heavily on following the requirement checklist, which is used throughout the design process to track progress. To assist design development, provide all critical team members—not limited to the architect, mechanical and electrical engineers, and lighting designer—with a checklist highlighting their appointed tasks.
The architect, mechanical engineer, and lighting designer need to discuss each requirement and its design ramifications. Hold these meetings every six to eight weeks to discuss progress and make sure all requirements are being met.
Confirm that your project team is comfortable with following all the prescribed requirements. If not, switch to Option 1: Whole Building Energy Simulation.
The LEED Online credit form does not specify how to document each prescriptive requirement because they are so different for each project; it only requires a signed confirmation by the MEP for meeting AEDG requirements. You still have to provide documentation. Submit your checklist of requirements, and supporting information for each item, through LEED Online to make your case. If your project fails to meet even one requirement, it will fail to earn the prerequisite, thus jeopardizing LEED certification.
Although energy modeling consultant costs are avoided by this option, additional staff time will be required to document and track compliance status, as compared with conventional projects.
Energy efficiency measures prescribed by the guide can be perceived as additional costs in comparison with conventional projects. However, they are easy to implement and are cost-effective pn the whole.
Become familiar with the Core Performance Guide early in the design phase to know the multiple requirements and all requisite documents.
Note that the guide demands additional time, attention, and integrated process from the design team as compared to conventional projects. It’s not just a list of prescriptive requirements, but a prescribed process for achieving energy efficiency goals. LEED Online documentation requires proof of all steps outlined in Sections 1 and 2, including three conceptual design options and meeting minutes. The project manager, architect, and mechanical engineer should read the complete Core Performance Guide carefully to know beforehand the prescriptive requirements in Sections 1 and 2.
The project manager must take responsibility for ensuring that the requirement checklist is on track.
For Section 3, the design team needs to identify three or more of the listed strategies as possible targets for the project.
Create a checklist of requirements and assign a responsible party to each item.
The Core Performance Guide requires an integrated design contributed by the architect, mechanical and electrical engineers, and lighting designer. The project manager must take responsibility for shepherding and documenting the collaborative process to demonstrate compliance.
A long documentation list can be overwhelming for your team, so create a detailed checklist with tasks delegated to individual team members, allowing each member to focus on assigned tasks. The checklist can function as a status tracking document and, finally, the deliverable for LEED Online.
The architect and engineer, and other project team members, continue to develop a high-performance building envelope with efficient mechanical and lighting systems.
Constant communication and feedback among project team members, owner, and if possible, operational staff, during design development can minimize construction as well as operational costs and keep your project on schedule.
If you change or go through value-engineering on any specifications, such as the solar-heat gain coefficient of glazing, for example, be aware of impacts on mechanical system sizing. Making changes like this might not pay off as much as it first appears.
Consider using building information modeling (BIM) tools to keep design decisions up to date and well documented for all team members.
Schedule delays can be avoided if all team members share their ideas and update documents during the design development process.
The modeler completes the energy analysis of the selected design and system and offers alternative scenarios for discussion. The modeler presents the energy cost reduction results to the team, identifying the LEED threshold achieved.
It’s helpful for the energy modeling report to include a simple payback analysis to assist the owner in making an informed decision on the operational savings of recommended features.
The architect and HVAC engineer should agree on the design, working with the cost estimator and owner.
Demonstrating reductions in non-regulated loads requires a rigorous definition of the baseline case. The loads must be totally equivalent, in terms of functionality, to the proposed design case. For example, reducing the number of computers in the building does not qualify as a legitimate reduction in non-regulated loads. However, the substitution of laptops for desktop computers, and utilization of flat-screen displays instead of CRTs for the same number of computers, may qualify as a reduction.
Residential and hospitality projects that use low-flow showers, lavatories, and kitchen sinks (contributing to WEp1) benefit from lower energy use due to reduced overall demand for hot water. However, for energy-savings calculations, these are considered process loads that must be modeled as identical in baseline and design cases, or you have the choice of demonstrating the savings with ECM for process loads.
Perform daylight calculations in conjunction with energy modeling to balance the potentially competing goals of more daylight versus higher solar-heat gain resulting in high cooling loads.
If your project is pursuing renewable energy, the energy generated is accounted for by using the PRM. These results provide information about whether the energy is contributing to EAc2: Onsite Renewable Energy.
A cost-benefit analysis can help the owner understand the return on investment of big-ticket, energy-conserving equipment that lowers operating energy bills with a quick payback.
Complete at least half of the energy modeling effort by the end of the design development stage. Help the design team to finalize strategy through intensive, early efforts in energy modeling. Once the team has a design direction, the modeler can develop a second model during the construction documents phase for final confirmation.
If pursuing ECM for non-regulated loads, calculate energy saving for each measure separately if you are, for example, installing an energy-efficient elevator instead of a typical one so that the reduction would contribute to total building energy savings. Calculate the anticipated energy use of the typical elevator in kBTUs or kWh. Using the same occupancy load, calculate the energy use of the efficient elevator. Incorporate the savings into design case energy use within the PRM. Refer to the ECM strategy for detailed calculation guidelines.
Ensure that all prescriptive requirements are incorporated into the design by the end of the design development stage.
Revisit the Advanced Energy Design Guides (AEDG) checklist to ensure that the design meets the prescriptive requirements.
The mechanical engineer, lighting consultant, and architect revisit the checklist for an update on the requirements and how they are being integrated into the design. All prescriptive requirements should be specifically incorporated into the design by the end of the design development phase.
The mechanical engineer and architect track the status of each requirement.
While the LEED Online credit form does not require detailed documentation for each Core Performance Guide requirement, it is important that each item be documented as required and reviewed by the rest of the team to confirm compliance, especially as further documentation may be requested by during review. Your design team should work with the owner to identify cost-effective strategies from Section 3 that can be pursued for the project.
Construction documents clearly detail the architectural and mechanical systems that address energy-efficiency strategies.
Confirm that specifications and the bid package integrate all equipment and activities associated with the project.
If the project goes through value engineering, refer to the OPR and BOD to ensure that no key comfort, health, productivity, daylight, or life-cycle cost concerns are sacrificed.
During the budget estimating phase, the project team may decide to remove some energy-saving strategies that have been identified as high-cost items during the value-engineering process. However, it is very important to help the project team understand that these so-called add-ons are actually integral to the building’s market value and the owner’s goals.
Removing an atrium, for example, due to high cost may provide additional saleable floor area, but may also reduce daylight penetration while increasing the lighting and conditioning loads.
Although this prerequisite is a design-phase submittal, it may make sense to submit it, along with EAc1, after construction. Your project could undergo changes during construction that might compel a new run of the energy model to obtain the latest energy-saving information. Waiting until the completion of construction ensures that the actual designed project is reflected in your energy model.
Create a final energy model based completely on construction document drawings—to confirm actual energy savings as compared to ASHRAE 90.1-2007 requirements. An energy model based on the construction documents phase will provide realistic energy-cost savings and corresponding LEED points likely to be earned.
Make sure the results fit the LEED Online credit form requirements. For example, the unmet load hours have to be less than 300 and process loads will raise a red flag if they’re not approximately 25%. If any of the results are off mark, take time to redo the model. Time spent in design saves more later on in the LEED review process.
Finalize all design decisions and confirm that you’ve met all of the prescriptive requirements. Your team must document the checklist with relevant project drawings, including wall sections, specifications, and the MEP drawing layout.
Value engineering and other factors can result in design changes that eliminate certain energy features relevant to the prerequisite. As this compliance path is prescriptive, your project cannot afford to drop even one prescribed item.
Value engineering and other factors can result in design changes that eliminate certain energy features relevant to the credit. As this compliance path is prescriptive, your project cannot afford to drop even one listed item. Although perceived as high-cost, prescriptive requirements lower energy costs during operation and provide a simple payback structure.
The architect and mechanical engineer review the shop drawings to confirm the installation of the selected systems.
The commissioning agent and the contractor conduct functional testing of all mechanical equipment in accordance with EAp1: Fundamental Commissioning and EAc3: Enhanced Commissioning.
Find your Energy Star rating with EPA’s Target Finder tool if your building type is in the database. Input your project location, size, and number of occupants, computers, and kitchen appliances. The target may be a percentage energy-use reduction compared to a code-compliant building, or “anticipated energy use” data from energy model results. Add information about your fuel use and rate, then click to “View Results.” Your Target Finder score should be documented at LEED Online.
Plan for frequent site visits by the mechanical designer and architect during construction and installation to make sure construction meets the design intent and specifications.
Emphasize team interaction and construction involvement when defining the project scope with key design team members. Contractor and designer meetings can help ensure correct construction practices and avoid high change-order costs for the owner.
Subcontractors may attempt to add a premium during the bidding process for any unusual or unknown materials or practices, so inform your construction bidders of any atypical design systems at the pre-bid meeting.
The energy modeler ensures that any final design changes have been incorporated into the updated model.
Upon finalizing of the design, the responsible party or energy modeler completes the LEED Online submittal with building design inputs and a PRM result energy summary.
Although EAp2 is a design phase submittals, it may make sense to submit it (along with EAc1) after construction. Your project could undergo changes during construction that might require a new run of the energy model. Waiting until the completion of construction ensures that your actual designed project is reflected. On the other hand, it gives you less opportunity to respond to questions that might come up during a LEED review.
Include supporting documents like equipment cut sheets, specifications and equipment schedules to demonstrate all energy efficiency measures claimed in the building.
It common for the LEED reviewers to make requests for more information. Go along with the process—it doesn’t mean that you’ve lost the credit. Provide as much information for LEED Online submittal as requested and possible.
The design team completes the LEED Online documentation, signing off on compliance with the applicable AEDG, and writing the narrative report on the design approach and key highlights.
During LEED submission, the project team needs to make an extra effort to support the prerequisite with the completed checklist and the required documents. Although the LEED rating system does not list detailed documentation, it is best practice to send in supporting documents for the prescriptive requirements from the AEDG. The supporting documents should include relevant narratives, wall sections, mechanical drawings, and calculations.
Although the LEED Online sign-off does not include a checklist of AEDG requirements, it assumes that the team member is confirming compliance with all detailed requirements of the guide.
The design team completes the LEED Online credit form, signing off on compliance with the Core Performance Guide, and writing the narrative report on the design approach and key highlights.
During LEED submission, your project team needs to make an extra effort to support the prerequisite with the completed checklist and the required documents. Although not every requirement may be mentioned in the LEED documentation, the supporting documents need to cover all requirements with narratives, wall sections, mechanical drawings, and calculations.
Many of this option’s compliance documents are common to other LEED credits or design documents, thus reducing duplicated efforts.
Develop an operations manual with input from the design team in collaboration with facility management and commissioning agent if pursuing EAc3: Enhanced Commissioning.
The benefit of designing for energy efficiency is realized only during operations and maintenance. Record energy use to confirm that your project is saving energy as anticipated. If you are not pursuing EAc5: Measurement and Verification, you can implement tracking procedures such as reviewing monthly energy bills or on-the-spot metering.
Some energy efficiency features may require special training for operations and maintenance personnel. For example, cogeneration and building automation systems require commissioning and operator training. Consider employing a trained professional to aid in creating operation manuals for specialty items.
Energy-efficiency measures with a higher first cost often provide large savings in energy use and operational energy bills. These credit requirements are directly tied to the benefits of efficient, low-cost operations.
Excerpted from LEED 2009 for New Construction and Major Renovations
To establish the minimum level of energy efficiency for the proposed building and systems to reduce environmental and economic impacts associated with excessive energy use.
Demonstrate a 10% improvement in the proposed building performance rating for new buildings, or a 5% improvement in the proposed building performance rating for major renovations to existing buildings, compared with the baseline building performanceBaseline building performance is the annual energy cost for a building design, used as a baseline for comparison with above-standard design. rating.
Calculate the baseline building performance rating according to the building performance rating method in Appendix G of ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1) using a computer simulation model for the whole building project. Projects outside the U.S. may use a USGBC approved equivalent standard2.
Appendix G of Standard 90.1-2007 requires that the energy analysis done for the building performance rating method include all energy costs associated with the building project. To achieve points using this credit, the proposed design must meet the following criteria:
For the purpose of this analysis, process energy is considered to include, but is not limited to, office and general miscellaneous equipment, computers, elevators and escalators,kitchen cooking and refrigeration, laundry washing and drying, lighting exempt from the lighting power allowance (e.g., lighting integral to medical equipment) and other (e.g., waterfall pumps).
Regulated (non-process) energy includes lighting (for the interior, parking garage, surface parking, façade, or building grounds, etc. except as noted above), heating, ventilation and air conditioning (HVAC) (for space heating, space cooling, fans, pumps, toilet exhaust, parking garage ventilation, kitchen hood exhaust, etc.), and service water heating for domestic or space heating purposes.
Process loads must be identical for both the baseline building performance rating and the proposed building performance rating. However, project teams may follow the exceptional calculation method (ANSI/ASHRAE/IESNA Standard 90.1-2007 G2.5) or USGBC approved equivalent to document measures that reduce process loads. Documentation of process load energy savings must include a list of the assumptions made for both the base and the proposed design, and theoretical or empirical information supporting these assumptions.
Projects in California may use Title 24-2005, Part 6 in place of ANSI/ASHRAE/IESNA Standard 90.1-2007 for Option 1.
Comply with the prescriptive measures of the ASHRAE Advanced Energy Design Guide appropriate to the project scope, outlined below. Project teams must comply with all applicable criteria as established in the Advanced Energy Design Guide for the climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. in which the building is located. Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
The building must meet the following requirements:
Comply with the prescriptive measures identified in the Advanced Buildings™ Core Performance™ Guide developed by the New Buildings Institute. The building must meet the following requirements:
Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
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.
Tanks for the reply.
Probably there is kind of interpreting misunderstanding - from my side.
It appears that what you call "preheat" is the heating coil which is in the AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. serving the 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. boxes of the system. As this is zone 5A there is always such preheating of the OA before entering in the VAV boxes.
Hope that now I've understand it properly, or ?
It can be in the AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. or it could be in a separate DOAS system. You only have it in the baseline system if it is in the corresponding proposed system.
This might have been asked before but will the new 18% prerequisite affect the projects following ASHRAE 90.1 2010 adjusted point scale for LEED 2009? Thanks.
No the adjusted point scale remains the same.
We're working on a small project (7,500 SF) pursuing LEED NC v2009 designed with water-source VRFs served by a shared central condenser water system with cooling towers, boilers, and pumping. The CW system is located entirely off-site (outside the LEED project boundary) and serves multiple buildings within a LEED Campus boundary. 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 #5234 provides some guidance on the issue, but not enough for a clear understanding of how to handle this particular system. The definition of a DES within the LEED DES Guidelines doesn't directly apply to CW systems, but we're still unclear on how to appropriately account for this system and what approach to take. Question #1: Do we have to follow the LEED DES Guidelines? If so, how do we handle the Baseline system (would be System #3). Question #2: Are we allowed to segment the central plant capacity - meaning since I know the percentage of the central plant attributed to this building can I model an on-site plant configured like the central plant but with reduced capacities, flows, etc?
Are you reading DES v2? They have two options. Options 1 is to use virtual utility rate and model the central plant cost-neutral in proposed and baseline. But in your case, I think option 2 is better suited for you since you have more efficient cooling plant. And your central plant is just cooling tower, you can just model it as on-site plant, which is described in detail in DES v2.
Thanks for your response. I think the issue here is that condenser water systems are not directly covered in DES v2 and technically the primary space heating/cooling is being performed on site with the plant serving more as a heat sink. This entire system (cooling tower, boilers, pumps) is located offsite with this building only accounting for ~10% of the total load on the plant. If I pursue Option 2, then part-load operation becomes a concern because this building accounts for such a small percentage of the total capacity. My previous questions was "Are we allowed to segment the central plant capacity - meaning since I know the percentage of the central plant attributed to this building can I model an on-site plant configured like the central plant but with reduced capacities, flows, etc?"
You are not required to use the DESv2 but if you don't you will need to justify your own modeling protocol for the situation.
Even though the system you have is not directly addressed you can apply the same principle in the DESv2 to your situation.
Under Option 2 you model a virtual central plant that is on-site and sized to your project. See section 126.96.36.199.
Perhaps the wrong thread, but as the update is mentioned here, does anyone happen to know whether a performance requirement update for EAp2 is also planned for LEED EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating systems. 2009?
I don't expect so—it would have been included in this update.
My engineers' submittal for this prerequisite resulted in a lengthy list of comments, with a requirement that a narrative response to each comment be provided. However, there doesn't seem to be a logical place to upload a response so that the reviewer will be able to find it. I am inclined to tell my engineer to check the "special circumstances" box at the bottom of the form and upload his narrative response there. Is this appropriate? I'd appreciate any feedback, or recommendations as to how to respond to the reviewer.
I usually just upload them with all other supporting document in EAp2 under the process load explanation. There is no specific place to upload the response but the reviewer should have no problem finding it if you name it as response to comments or other obvious names
Thanks. We'll try it that way.
Hi all. Can we use latest standard of ASHRAE 90.1 2013 instead of 2007 as stipulated at reference guide? Noted that the latest standard will have more stringent requirement.
There is an interpretation concerning the use of the ASHRAE 90.1-2010 for LEED 2009 projects:
I have never heard about the use of ASHRAE 90.1-2013 for LEED 2009 projects. Why would you like to use v. 2013?
I do not believe that USGBC has developed an interpolation table related to 90.1-2013 yet.
Hi all, the reason is we are planning to use some assumption at ASHRAE 90.1 User Manual for our Energy Modelling. Since we can't purchase the older version. We only can purchase 2013 version. Any idea whether there is any implication on using ASHRAE 90.1 - 2013 User Manuals?
You can purchase older version here.
we are working on a project for which our client would like to pursue a Major Renovation certification.
All air handlers will be replaced. However, the client would like to keep the existing chiller.
For new construction projects, our 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. (1A) requires the baseline HVAC system 8 - VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with PFP Boxes and 2 water-cooled screw chillers.
Would we be allowed to use our existing chillers (2 air-cooled chillers with lower CoP than the ASHRAE 90.1 reference) for both our baseline and proposed building models since this equipment will not change?
Yes you can model the existing chiller in both models.
Thank you very much for your answer, Marcus. We will apply your recommendation.
I've received a comment from the LEED reviewer after they denied my approach in calculating the LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. for the proposed building (dwelling units).
They recommended to follow the "The Energy Star Multifamily High Rise Program Simulation Guidelines, section 188.8.131.52 says:
- "Hardwired fixtures in rooms, such as bedrooms and living rooms, that may be supplemented by lighting that is connected to receptacles must be estimated to provide illumination at a rate of no more than 3 ft2 per Watt."
But in some spaces (all bedrooms) the designed lighting provide illumination at a higher rate (over 7 ft2 per watt)?
Shall I only use 3 ft2 per my provided watts and account for the rest of the area using the 1.1 Baseline LPD?
Also the In-unit lighting worksheet of the Performance Path Calculator, calculates the Proposed LPD. Should this number be applied for all the proposed spaces identically (ex; all spaces would get 0.8 LPD)? although it is a combination of the actual design layout for the hardwired fixtures (0.5 LPD for some spaces like bedrooms) and the plug-ins lighting (1.1 LPD for the spaces with no fixtures on the layout like living rooms).
I hope someone here who went through this before can assist me to get over it too. Thank you in advance.
The proposed is modeled as designed. So if it is greater than the baseline allowance you model it that way.
Residential in-unit lighting is not regulated by 90.1. So you must model it identically in both models. If you wish to claim savings you follow the guidelines above. You can only claim savings for hardwired fixtures. The spaces must meet the illumination requirements in the guidelines and you need to demonstrate with room photometrics that they do meet those illumination levels. The proposed is modeled as designed. Any spaces or supplemental lighting in hardwired spaces must be modeled identically in both models at 1.1 W/sf. The baseline is 1.1W/sf. The lighting schedule is also restricted to 2.34 h/d.
The issue of 3 sf/W as a restriction limits the illumination from hardwired fixtures. If you have 7sf/W that means you have a lower rate of illumination, not a higher one. If that is the case i would be concerned that you will not be able to meet the illumination requirements at all. If you can't meet the illumination requirements you cannot use this methodology. By far the hardest part of this methodology is demonstrating that you meet the minimum illumination requirements since photometrics are not often generated for this type of project. I would start there and if you meet the illumination requirements then try and figure out the wattage per area to include in the units.
Thank you, Marcus for your response. I have some points to discuss here;
- I got a bit confused when you said "The proposed is modeled as designed. Any spaces or supplemental lighting in hardwired spaces must be modeled identically in both models at 1.1 W/sf. The baseline is 1.1W/sf." Well the hardwired spaces are the spaces with designed fixtures, do I model these ones as designed (0.5 W/sf) or identically to the baseline as (1.1 W/sf). I do understand that I should design the spaces with NO specified hardwired lighting in the proposed model as (1.1 W/sf).
- The way I apply the 3sf/W restriction limit is that I only apply it to a specific area in the space to match this rule and I apply 1.1 W/sf for the rest of the space (ex: if the fixture is 5 watts and the area is 20 ft2, I apply the 3ft/W for only 15 ft2 and the rest of the area would be modeled as 1.1 W/sf, so in average the space LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. will be 0.525 W/sf). The MFHR Performance Path Calculator does it in this way to find the average LPD of the space.
- In those spaces with hardwired fixtures you model the Proposed as designed.
- I do not think that is how it works. Let's say you have a hard wired fixture in a 10x10 bedroom. Your fixture would be limited to 33 watts.The bedroom must meet the illumination requirements without any supplemental lighting. If it doesn't you can't claim any savings in that room.
Perhaps if your room was L shaped and one leg had a hardwired fixture and the other did not you would separate the hardwired area from the non-hardwired area and the non-hardwired area would be 1.1 W/sf. That is my guess about what the calculator is trying to do. It would make sense when you had a space with a mix of hardwired and non-hardwired lighting. It would not make sense in a space with only hardwired lighting.
We are renovating a 1905 two-story small historical landmark building as a 12 room boutique hotel, thus cannot include HVAC systems due to planning and preservation restrictions, and the location does not have 4 seasons or summer/winter peaks, with a constant temperature all year long. For thermal comfort at night we are using an efficient electrical wall heater per room which the guest can turn on or off as needed. For this "optimize energy performance" pre-req and credits we are doing a whole building simulation, and do not know how to best include the wall heaters in the comparison, as we do not want the energy model to be rejected for wrong inputs in the system. So far we are including the wall heaters as miscellaneous loads, with the actual consumption of the panel in each room, and will be modeling the baseline with the same load. The question is if this load can actually be considered in plug loads or miscellaneous loads or does it need to be modeled as heating load? how to do this when the units do not turn on at a set point but rather the user decides to turn it on or of? Can we get away with including it in the design case but eliminating it from the baseline to avoid confusion even if this results in lower energy reduction for the design case?
It must be modeled as heating. It cannot be placed in the space as a load because it is the system that must meet the heating load. If you have electric space heating in a hotel room the baseline will be a packaged terminal 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. so you cannot model the baseline with the same load.
To model the operation you will need to assume a set point and then develop a schedule with will most accurately reflect the expected operation of the system.
If you include it in the design case and exclude it from the baseline the savings will increase and that would not be acceptable.
We have a hotel guest room that will use natural ventilation to meet the building code requirement for ventilation. In this case, I wonder how we should model the baseline case. Should it use natural ventilation as well or using 62.1 minimum requirement?
The fans in the Proposed HVAC system would be allowed to cycle since outdoor air is supplied by natural ventilation, while the Baseline HVAC system would supply the outdoor air mechanically and therefore require continuous fan operation during regularly occupied periods. The volume of outdoor air should remain identical and in both cases would still introduce an identical load on the system, but the method of delivery would be different. The baseline would be through the mechanical system and the Proposed through constant infiltration. This methodology is currently allowed within the LEED energy modeling protocol
Thanks for your help!
Is the methodology that you proposed supported by some statements of ASHRAE 90.1, Marcus?
In the past I modeled natural ventilation in the same way in the proposed model and in the baseline model. I modeled it as a "special infiltration", i.e. the ventilation doesn't occur when the outdoor conditions are extreme or when the building isn't occupied. As flow rates I considered ASHRAE 62.1, althought natural ventilation is obviously much less regular than mechanical ventilation.
I think the best way to think of window ventilation is as a DVC system. As such, I believe the baseline should be modeled with a mechanical delivery of ODA as a DVC such as to take account of heat recovery, which windows can't. The window ventilation should be modeled as a DVC system that responds such as to represent how the occupants would react and consider at a minimum thermal comfort and CO2Carbon dioxide concentration. The infiltration should modelled identically.
In Francesco's way both models must condition the same amount of ODA, but baseline can't take advantage of heat recovery to precondition outdoor air for free which is the one of the big reasons that window ventilation sucks...the other being the thermal comfort degredation.
The energy credit should keep its nose out of the comfort credit and the comfort credit should include air quality as a prereq and not just thermal comfort. If you have NatVent, you should be required to demonstrate this.
No one opens windows enough in winter.
With natural ventilation you don't have heat recovery but you save the energy that is needed by the fans. Advantages and disadvantage depend on the climate.
Although true that you save fan energy and maintenance, in the balance I find mechanical ventilation with heat recovery more sustainable...for most climates and most projects (especially those in CZ 4 and greater). I find you save sooo much energy in the two months of cold winter that it is simply difficalt to "make up" that amount of energy over the rest of the year. Take fan energy, as an example: as we move into the future EC motors become common place (already required by legislation in the EU), frequency converters as well, i.e. VSDs, and the recovery rates of heat recovery devices for larger commercial applications are pretty darn good. Energy saving aside, people have been kidding themselves about the IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors. of window ventilated spaces for a long time. And occupant comfort is seldom comparable.
Last but not least, I would point out that NatVent only works when properly designed...very few know how to do this IMO, and getting it done cheap and fast is not possible, so its not ordered that often. When was the last time you saw a NatVent "properly designed" building? Painting pretty arrows on how you expect the flows to go based on perfect (unpredictable) conditions does not count. End of rant. Sorry.
Your statements are correct and interesting, Jean. But if we consider the difference between theory and practice, I saw some pictures relative to some AHUs that were extremely dirty (actually the images were pretty terrifying...). If AHUs are not cleaned properly they don't guarantee air quality.
Anyway, I would like to understand whether the approach that I used for the baseline model is wrong according to ASHRAE.
The methodology is allowed by LEED as the adopting authority. I am not aware of it directly mentioned in 90.1.
Thank you, Marcus.
What do you think of the following approach?
In the past I modeled natural ventilation in the same way in the proposed model and in the baseline model. I modeled it as a "special infiltration", i.e. the ventilation doesn't occur when the outdoor conditions are extreme or when the building isn't occupied. As flow rates I considered ASHRAE 62.1, althought natural ventilation is obviously much less regular than mechanical ventilation.
As long as you model the special infiltration the same in both models there should be no problem with the approach described.
We are modeling a hospital building which is served by two 800kW CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. systems. The CHP systems are dedicated to this building only, i.e. Case 1 (same ownership, inside building) in the Reference Guide. The Reference Guide says that we should either simulate the system or do manual post-processing to calculate the hourly CHP performance. In our simulation tool (EnergyPlus), we cannot model the CHP directly. So, we have two questions regarding the two options recommended by the guide;
1. Since we cannot model the CHP directly, should we model the CHP following the calculation methodology in DES Guidance Appendix D?
2. Our second option is modeling the CHP in another tool (EnergyPro) and inserting the hourly performance results in the Exceptional Calculation Methodology section. Does this comply with ‘manual post-processing’?
Thanks in advance.
Are you sure EnergyPlus can't model a CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. system? I would think that it could do so.
1. No, Appendix D of the DESv2 only applies to district CHP systems where the energy used and generated by the CHP needs to be proportioned to more than one building. This does not apply to a CHP solely dedicated to an individual project.
2. If you are going to do that and EnergyPlus can't model the CHP then I would just use EnergyPro and avoid the potential problems of trying to reconcile two different models. Technically you could probably do what you suggest but it seems like a lot of extra effort that is not necessary.
Thank you Marcus. Indeed, EnergyPlus can model CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. systems but it can only model small scale residential 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. systems. That's why we cannot use this module directly. So, we will proceed with the second option and consider you advice. Thank you.
I am doing an ASHRAE 90.1-2007 PRM analysis. We have a DOAS CV laboratory design that has a requirement between 10-20ACH in lab zones and a room set point of 20degC.
The baseline system is System 5 – Packaged VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with Reheat
Section G184.108.40.206 states airflow rates shall be sized off supply-air-to-room-air difference of 11degC, or the required ventilation air/makeup air, whichever is greater. In our case the required ventilation rate is greater than the flow rate using an 11degC temperature difference (supplying at 9degC).
Design outdoor air requirement =12,400l/s
Supply flow rate at 11degC temperature difference = 7,500l/s
My question is, for the baseline building do we still supply our outdoor 12,400l/s air at 9degC + 2.3degC supply reset (G220.127.116.11) from the AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork.? Doing this leads to the baseline overcooling to 11.3degC (9+2.3) and then re-heating to 17-18degC to achieve the space set-point of 20degC. This creates an inefficient baseline and therefore a positive effect for the energy cost saving.
The same problem seems to have been posted here, with the answer suggesting that this is acceptable to overcool and then reheat:
Any help would be much appreciated.
It appears as if G3.1.1 exception d applies, so the 50% reduction applies during unoccupied periods. The rest of what you included above sounds right.
Marcus, thanks for your response. This proposed Laboratory system uses 2 AHU’s per floor, one AHU will be conditioning a wing to 25-35% RH 20degC during all occupied hours, the 2nd will be conditioning a wing to a more standard 40-70%RH 20degC. The baseline is system type 5, with one per floor.
To achieve the low 25% to 35% RH and 20degC the proposed system is using chemical desiccant dehumidification. To achieve 25%-35% RH and 20degC in the baseline the cooling coil off coil temperature of System type 5 would need to be 2degC (using a psychrometric chart).
Firstly, is it acceptable to change the baseline System type 5 cooling coil off coil temperature to 2degC, and therefore no longer be supplying at the 11degC delta T required by G18.104.22.168 (it would now be 18degC delta T).
Secondly, because there is only one system per floor in the baseline, this would then mean both wings would have to be conditioned at 25-35%RH (rather than only one wing) as the baseline has no re-humidification method for the wing with 40%-70% RH requirement. Does this then mean the low RH% wing needs to be modelled as System Type-3 but still with the 2degC cooling coil off coil temperature?
Thanks for your help.
1. No you can't change that parameter.
2. Check the exceptions to G3.1.1 to see if any apply. If they do you must implement them in the baseline. The humidity setting must be identical in both models. Any humidification system is considered a process load and must be modeled identically.
To clarify, from reading your second point dehumidification should also be modelled identically? Therefore the baseline will need to be modelled with a desiccant dehumidifier identical to the proposed rather than reducing the baseline cooling off-coil temperature.
I don’t see any other method for achieving the low RH requirement.
Dehumidification beyond what is required for the comfort of people would be considered a process load and should also be modeled identically.
This starts April 8th.
The Design Preliminary Review has been completed on one of my projects and we have one query from EAp2 which appears unclear. It states that ‘heating equipment should be heat pumps in both Baseline and Proposed Case’. The building has been designed with heat pumps for heating and hot water generation.
My query is; does the Baseline hot water generation need to be heat pumps? I have checked ASHRAE 90.1 Table 7.8 Performance Requirements for Water Heating Equipment and ‘electric water heater’ seems to be the only Baseline hot water heating equipment that I can select. Whether I use a heat pump or electric water heater for the Baseline has a big impact on energy consumption so would appreciate advice on this.
2 things come to mind:
- Your HVAC is not yet designed, in which case the HVAC for the two models is the same
- Your system type for the baseline is System 1 because this is a residential (includes hotel) project (Table G3.1.1A)
Hi Jean, thanks for your reply. Just to add further clarity the HVAC systems have been fully designed for this new building. We are using a heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. for space heating and service hot water. Also the building type is a commercial motorway fuel / gas station. Based on this should the baseline hot water system use a heat pump OR electric water heater ? Many thanks in advance.
(correction to previous comment -- System 2 PTHP for Residential, as in your case your proposed case heating fuel type is "electric" HP)
- If the predominant ft² is "motel" then it will count as residential.
- if the project ft² < 2300 m² (SI) & Nonres. and the preposed case has electric HP then you're looking at System 4 -- PSZ-HP
So is it correct to say that the DHWDomestic hot water (DHW) is water used for food preparation, cleaning and sanitation and personal hygiene, but not heating. / service hot water should be fueled via 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. as per the proposed. I am just referring to the hot water element of the model and not the HVAC system. Could you clarify please.
Technically the baseline hot water system is a heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. according to Table 7.8. However, the performance required for the "heat pump" is the same formula as for a small electric water heater. This is a bit confusing. The bottom line is that if you have a heat pump water heater in the proposed the baseline efficiency is calculated as if it was an electric resistance water heater. You should be able to claim the significant savings associated with a heat pump water heater.
Thanks all for your guidance above.
when will the results of the ballot be posted?
We have a project that consists of two connected buildings: an admin building and a factory building. The total area for the buildings is greater than 150,000 sq ft, therefore system 8 applies to the baseline case model. Unfortunately, our proposed system uses air cooled chillers and we are having a hard time achieving the required savings.
According to the USGBC, 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.
The above link is broken, and we cannot find anything on the USGBC website that gives guidance on alternative standards to ASHRAE 90.1-2007. So my question is, are there any approved alternative standards to ASHRAE 90.1-2007 for international projects? Has anyone successfully submitted an energy model using a different standard? On another note, is it even possible to achieve the required savings, without using water-cooled chillers, if your baseline model uses system 8 - VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with PFP Boxes?
Your feedback is greatly appreciated.
I am not aware of alternative standards.
Achieving the savings is possible. Consider that cooling is not the only end use.
Moreover, I think that the water cooled chillers of the baseline require an important amount of energy for pumping. What do people having more experience think about this point?
I do not recall an alternative baseline being approved yet. The process is pretty rigorous and requires some in depth modeling studies. It would be well beyond something an individual project team could attempt.
You will need to find the minimum savings elsewhere. Quite often manufacturing facilities will need to find energy savings within their process loads. There is an alternative compliance path for manufacturing facilities which can be found here.
We also have had similar problems in projects in Mexico in some areas where water is scarce and has a high amount of minerals, so cooling towers are not installed in HVAC systems because of the high O&M costs. We then try to achieve energy savings in other areas such as fan power consumption, pumping energy and interior lighting. In hot climate areas it can be difficult to achieve the minimum energy savings treshold because cooling is one of the highest end uses, so if your project is still in the version 3 of LEED you can also try to recommend the client to install an on site renewable energy system to achieve the required energy savings. In version 4, however, renewable energy systems cannot be accounted for pre-requisite EAp2, which makes good sense.
Is anyone aware of exemptions or opportunities to take additional credit for senior care/assisted living facilities? Someone mentioned they thought there were due to need for lighting and temperature accommodations, but didn't know the details and we have not found anything concrete in ASHRAE about this. Thanks!
Am not aware of any specific exemptions.
The lighting power density does not increase for older eyes. I think this is already accounted for in the LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. values. Temperature settings can be higher that other facilities they just need to be identical in the baseline.
The primary opportunity I see is that the facility runs 24/7 so any savings you can generate out of the systems will produce a greater amount of energy savings.
We are looking at a high rise residential project, to be NCV2009. Our electrician is stating all hallways need occupancy sensors. We believe this is not a practical option for the hallways of an apartment building, as they are 24 hour operation AND a security issue. Would they be required by the USGBC? This seems to meet the exception list for 22.214.171.124.
Also, how does this apply to the apartment units themselves? Thanks.
I agree that the hallway lighting would meet exception a and c of 126.96.36.199.
I think exception a applies to the apartments themselves.
We are doing Energy Simulation for Sports Hall Project (G+1 Story building). Sports hall having single playing court and it will be used for various sports activities. Sometimes, it will used for playing Badminton. Sometimes for Basket ball. Further, the sports hall has closed and surrounded with seating areas, camera/media rooms and other admin offices.
Areas: Sports Hall - 80% of total buildup area, Rest of the areas (Seating, office etc) - Rest 20%.
1. In Base case, we considered 1.4 W per Sq.ft for Indoor playing Field Area. Is it right?
2. The proposed LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. for Sports hall is 3.75 W/sq.ft. So we are not meeting the Minimum Energy
In this case, Whether we can get exception for this space (i.e sports hall) alone.
3. For getting exception, what are the design strategies need to be informed to client?
FYI - They (client) are not ready to reduce the LPD by reducing the no of lights or changing the wattage.
Please Help with ideas/solution.
Sam, I would argue that a multipurpose sports arena is not a "Gymnasium/Exercise Center". Other than the Seating Area for Sports arena, this kind of lighting is not regulated and is therefor a process load. It has to do with minimum lighting levels required by HD Television Cameras, Slow-motion cameras and regulations by organisations such as FIFA.
Be warned that certifying facilities with high process loads is hard, because they destroy energy...loads of it.
Thanks for the reply and agree with you.
Could u tell answer with more clearly for above raised questions?
LEEDuser is produced by BuildingGreen, Inc., with YR&G authoring most of the original content. LEEDuser enjoys ongoing collaboration with USGBC. Read more about our team
Copyright 2016 – BuildingGreen, Inc.