This prerequisite is a big one, not only because it’s required for all projects, but also because it feeds directly into EAc1: Optimize Energy Performance, where about a fifth of the total available points in LEED are at stake. Master these minimum requirements, and you can use the same compliance path as in EAp2 to earning points.
You won’t earn the prerequisite by accident, though. Although “energy efficiency” is on everyone’s lips, the mandatory and performance-based requirements for EAp2 go beyond code compliance in most places. That said, there is nothing to stop you from meeting the requirements with a reasonable amount of effort, and the environmental benefits as well as the operational cost savings are significant.
Most projects start by choosing which of the three available compliance paths to follow. We’ll look at them each in turn.
Option 1 alone gives you access to all of the points available through EAc1, and offers the most flexibility in giving you credit for innovative designs.
First, you need to meet the mandatory requirements of ASHRAE 90.1-2007 for all major components, including the envelope, HVAC, lighting, and domestic hot water. ASHRAE 90.1 has had some changes and new mandatory requirements since the 2004 version, which was referenced on previous LEED systems, so be sure to review the standard carefully.
Energy efficiency is an area where it behooves project teams to start early and work together to maximize savings. Playing catch-up later on can be costly.Second, you need to demonstrate a 10% savings (5% for existing buildings) for your designed building compared with a baseline case meeting the minimum requirements of ASHRAE 90.1 (or Title 24-2005, Part 6 for California projects). You do this by creating a computer model following rules described in Appendix G of ASHRAE 90.1.
Computer modeling offers the following key advantages:
Your building type may not have a choice—you may have to follow this path, because both Options 2 and 3 are prescriptive compliance paths that are only available to specific building types and sizes.
However, if your building type and size allow, and you don’t want to embark on the complex process of computer modeling, which also requires expert assistance from a modeler or from a member of the mechanical engineer’s team, the prescriptive compliance paths are a good way to earn the prerequisite simply by following a checklist.
Passive design strategies such as shading to reduce solar heat gain are the most cost-effective ways to improve energy performance.Note, however, that when you get to EAc1, there are a lot fewer points on the table for the prescriptive paths, and that you have to follow each prescriptive requirement. These paths also require more collaboration and focus early on in design than you might think. The design team must work together to integrate all of the prescriptive requirements, and Option 3 even requires documentation of certain design processes.
The Advanced Energy Design Guides are published by ASHRAE for office, warehouse, and retail projects less than 20,000 ft2—so if you don’t fall into one of those categories, you’re not eligible for this path.
These guides outline strategies to reduce energy use by 30% from 2001 levels, or an amount equivalent to approximately 10%–14% reduction from ASHRAE 90.1-2007. If you choose this compliance path, become familiar with the list of prescriptive requirements and commit to meeting all of them.
The Core Performance Guide path is a good option if all of the following are true:
Comply with all requirements within Sections 1 and 2 of the guide. If you choose this path, become familiar with the list of prescriptive requirements and commit to meeting them. Also note that it’s not just a list of prescriptive requirements, but a prescribed process for achieving energy efficiency goals. You must demonstrate that you considered a couple of alternate designs, for example, and that certain team meetings were held.
Energy efficiency offers a clear combination of environmental benefit and benefit to the owner through reduced operational expenses, and potentially reduced first costs, if you’re able to reduce the size and complexity of your HVAC system with a more efficient envelope.
High-tech HVAC systems, and onsite renewable energy generation are often signature components of green buildings, but consider these strategies more “icing” on the cake, rather than a place to start. Start with building orientation and passive design features first. Also look at envelope design, such as energy-efficient windows, walls and roof, before looking at HVAC and plug loads. A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective.
Projects connected to district energy systems will not be able to utilize the system efficiencies of the base plant to demonstrate compliance with the prerequisite. They can plan on benefiting from these systems under EAc1, however.
Focusing on energy efficiency and renewable energy generation can seem to add costs to a project, but there are a variety of utility-provided, as well as state, and federal incentives available to offset those premiums. (See Resources.)
Ideally if the software you are using cannot model a technology directly then seek a published workaround related to your software. If you can't find a published workaround then model it as you think it should be modeled and explain how you have modeled it in the preliminary LEED submission.
No, not if it is part of the LEED project. However, there is an exemption for existing building envelopes in Appendix G that allow you to model the existing condition in the baseline so you do not pay a penalty.
No, not for an existing building.
You must model accurately. Since you don't have enough savings in the building energy, find savings in the process. Either you will be able to demonstrate that compared to a conventional baseline the process being installed into the factory is demonstrably better than "similar newly constructed facilities," allowing you to claim some savings, or the owner needs to install some energy-saving measures into the process to get the project the rest of the way there. Either option can be difficult, but not impossible.
Account for process load reductions through the exceptional calculation method. A baseline must be established based on standard practice for the process in your location. Any claim of energy savings needs a thorough narrative explaining the baseline and the strategy for energy savings along with an explanation of how the savings were calculated.
It is common to have a 80%–90% process load in a manufacturing facility. The 25% default in LEED is based on office buildings. If you think your load is lower than 25%, it is recommended that you explain why in a short narrative. It is also recommended to briefly explain it if your load is 25% exactly, since that level commonly reveals that the process loads were not accurately represented.
The energy savings are based on the whole building energy use—building and process. LEED does not stipulate exactly where they come from.
For LEED 2009 you'll need touse 90.1-2007. There were some significant changes in 90.1-2010—too many to account for in your LEED review, and your project would also have a much harder time demonstrating the same percentage energy savings.
Yes according to LEED, although it is not recommended as a best practice, and it is usually more cost-effective to invest in energy savings in the building.
You can assume exterior lighting savings for canopies against the baseline, but not the shading effects of canopies.
If exterior lighting is present on the project site, consider it as a constant in both energy model cases.
Any conditioned area must be included in the energy model.
The Energy Star portion of the form does not apply to international projects.
Use the tables and definitions provided in 90.1 Appendix B to determine an equivalent ASHRAE climate zone.
International projects are not required to enter a Target Finder score. Target Finder is based on U.S. energy use data.
For Section 184.108.40.206c, a manual control device would be sufficient to comply with mandatory provisions.
Submitting these forms is not common; however, it can be beneficial if you are applying for any exceptions.
Use the building area method.
Although there is no formal list of approved simulation tools, there are a few requirements per G2.2.1, including the ability of the program to provide hourly simulation for 8760 hours per year, and model ten or more thermal zones, which PHPP does not meet.
The automated Trace 700 report provides less information than is requested by the Section 1.4 tables spreadsheet. The Section 1.4 tables spreadsheet must be completed.
Assign HVAC systems as per Appendix-G and Section 6 but set thermostatic setpointsSetpoints are normal operating ranges for building systems and indoor environmental quality. When the building systems are outside of their normal operating range, action is taken by the building operator or automation system. out of range so that systems never turn on.
If it is only used for backup and not for regular use such as peak shaving—no.
SHGC is not a mandatory provision so it is available for trade-off and can be higher than the baseline.
You generally wouldn't need to upload any documentation, but particularly for a non-U.S. project, it may help to provide a short narrative about what they are based on.
Discuss your project’s energy performance objectives, along with how those are shaping design decisions, with the owner. Record energy targets in the Owners Project Requirements (OPR) for the commissioning credits EAp1 and EAc3.
You won’t earn this prerequisite by accident. The energy efficiency requirements here are typically much more stringent than local codes, so plan on giving it special attention with your team, including leadership from the owner.
Consider stating goals in terms of minimum efficiency levels and specific payback periods. For example: “Our goal is to exceed a 20% reduction from ASHRAE 90.1, with all efficiency measures having a payback period of 10 years or less.”
Develop a precedent for energy targets by conducting research on similar building types and using the EPA’s Target Finder program. (See Resources.)
For Option 1 only, you will need to comply with the mandatory requirements of ASHRAE 90.1-2007, to bring your project to the minimum level of performance. The ASHRAE 90.1-2007 User’s Manual is a great resource, with illustrated examples of solutions for meeting the requirements.
ASHRAE 90.1-2007 has some additional requirements compared with 2004. Read through the standard for a complete update. The following are some samples.
The prerequisite’s energy-reduction target of 10% is not common practice and is considered beyond code compliance.
Indirect sunlight delievered through clerestories like this helps reduce lighting loads as well as cooling loads. Photo – YRG Sustainability, Project – Cooper Union, New York A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective. Start with building orientation and passive design features first when looking for energy efficiency. Also look at envelope design, such as energy-efficient windows, walls and roof, before looking at HVAC and plug loads. HVAC may also be a good place to improve performance with more efficient equipment, but first reducing loads with smaller equipment can lead to even greater operational and upfront savings. A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective.
Don’t plan on using onsite renewable energy generation (see EAc2) to make your building energy-efficient. It is almost always more cost-effective to make an efficient building, and then to add renewables like photovoltaics as the “icing” on the cake.
Some rules of thumb to reduce energy use are:
Find the best credit compliance path based on your building type and energy-efficiency targets. Use the following considerations, noting that some projects are more suited to a prescriptive approach than others.
Option 1: Whole Building Energy Simulation requires estimating the energy use of the whole building over a calendar year, using methodology established by ASHRAE 90.1-2007, Appendix G. Option 1 establishes a computer model of the building’s architectural design and all mechanical, electrical, domestic hot water, plug load, and other energy-consuming systems and devices. The model incorporates the occupancy load and a schedule representing projected usage in order to predict energy use. This compliance path does not prescribe any technology or strategy, but requires a minimum reduction in total energy cost of 10% (5% for an existing building), compared to a baseline building with the same form and design but using systems compliant with ASHRAE 90.1-2007. You can earn additional LEED points through EAc1 for cost reductions of 12% and greater (8% for existing buildings).
Option 2: Prescriptive Compliance Path: ASHRAE Advanced Energy Design Guide refers to design guides published by ASHRAE for office, school, warehouse, and retail projects. These guides outline strategies to reduce energy use by 30% from ASHRAE 90.1-2001 levels, or an amount equivalent to a 10%–14% reduction from the ASHRAE 90.1-2007 standard. If you choose this compliance path, become familiar with the list of prescriptive requirements and commit to meeting them. (See the AEDG checklist in the Documentation Toolkit.)
Option 3: Prescriptive Compliance Path: Advanced Buildings Core Performance Guide is another, more basic prescriptive path. It’s a good option if your project is smaller than 100,000 ft2, cannot pursue Option 2 (because there is not an ASHRAE guide for the building type), is not a healthcare facility, lab, or warehouse—or you would rather not commit to the energy modeling required for Option 1. Your project can be of any other building type (such as office or retail). To meet the prerequisite, you must comply with all requirements within Sections 1 and 2 of the guide. If you choose this path, become familiar with the list of activities and requirements and commit to meeting them. (See Resources for a link to the Core Performance Guide and the Documentation Toolkit for the checklist of prescriptive items.)
EAc1: Optimize Energy Performance uses the same structure of Options 1–3, so it makes sense to think about the credit and the prerequisite together when making your choice. In EAc1, Option 1 offers the potential for far more points than Options 2 and 3, so if you see your project as a likely candidate for earning those points, Option 1 may be best.
Hotels, multifamily residential, and unconventional commercial buildings may not be eligible for either Option 2 or Option 3, because the prescriptive guidance of these paths was not intended for them. Complex projects, unconventional building types, off-grid projects, or those with high energy-reduction goals are better off pursuing Option 1, which provides the opportunity to explore more flexible and innovative efficiency strategies and to trade off high-energy uses for lower ones.
If your project combines new construction and existing building renovation then whatever portion contains more than 50% of the floor area would determine the energy thresholds.
Options 2 and 3 are suitable for small, conventional building types that may not have as much to gain from detailed energy modeling with Option 1.
Meeting the prescriptive requirements of Options 2 and 3 is not common practice and requires a high degree of attention to detail by your project team. (See the Documentation Toolkit for the Core Performance Guide Checklist.) These paths are more straightforward than Option 1, but don’t think of them as easy.
Options 2 and 3 require additional consultant time from architects and MEP engineers over typical design commitment, which means higher upfront costs.
Option 1 references the mandatory requirements of ASHRAE 90.1-2007, which are more stringent than earlier LEED rating systems that referred to ASHRAE 90.1-2004.
Option 1 energy simulation provides monthly and annual operating energy use and cost breakdowns. You can complete multiple iterations, refining energy-efficiency strategies each time. Payback periods can be quickly computed for efficiency strategies using their additional first costs. A building’s life is assumed to be 60 years. A payback period of five years is considered a very good choice, and 10 years is typically considered reasonable. Consult the OPR for your owners’ goals while selecting your efficiency strategies.
Option 1 energy simulation often requires hiring an energy modeling consultant, adding a cost (although this ranges, it is typically on the order of $0.10–$0.50/ft2 depending on the complexity). However, these fees produce high value in terms of design and decision-making assistance, and especially for complex or larger projects can be well worth the investment.
All compliance path options may require both the architectural and engineering teams to take some time in addition to project management to review the prescriptive checklists, fill out the LEED Online credit form, and develop the compliance document.
The architect, mechanical engineer, and lighting designer need to familiarize themselves and confirm compliance with the mandatory requirements of ASHRAE 90.1-2007, sections 5–9.
Use simple computer tools like SketchUp and Green Building Studio that are now available with energy analysis plug-ins to generate a first-order estimate of building energy use within a climate context and to identify a design direction. Note that you may need to refer to different software may not be the one used to develop complete the whole building energy simulations necessary for LEED certification.
Energy modeling can inform your project team from the start of design. Early on, review site climate data—such as temperature, humidity and wind, available from most energy software—as a team. Evaluate the site context and the microclimate, noting the effects of neighboring buildings, bodies of water, and vegetation. Estimate the distribution of energy across major end uses (such as space heating and cooling, lighting, plug loads, hot water, and any additional energy uses), targeting high-energy-use areas to focus on during design.
Use a preliminary energy use breakdown like this one to identify target areas for energy savings.Perform preliminary energy modeling in advance of the schematic design phase kick-off meeting or design charrette. The energy use breakdown can help identify targets for energy savings and point toward possible alternatives.
For existing buildings, the baseline energy model can reflect the pre-renovation features like rather than a minimally ASHRAE-compliant building. This will help you achieve additional savings in comparison with the baseline.
Projects generating renewable energy onsite should use Option 1 to best demonstrate EAp2 compliance and maximize points under EAc1. Other options are possible but won’t provide as much benefit. Like any other project, model the baseline case as a system compliant with ASHRAE 90.1-2007, using grid-connected electricity, and the design case is an “as-designed” system also using grid-connected electricity. You then plug in 100% onsite renewable energy in the final energy-cost comparison table, as required by the performance rating method (PRM) or the modeling protocol of ASHRRAE 90.1 2007, Appendix G. (Refer to the sample PRM tables in the Documentation Toolkit for taking account of onsite renewable energy.
LEED divides energy-using systems into two categories:
The energy model itself will not account for any change in plug loads from the baseline case, even if your project is making a conscious effort to purchase Energy Star or other efficient equipment. Any improvement made in plug loads must be documented separately, using the exceptional calculation methodology (ECM), as described in ASHRAE 90.1-2007. These calculations determine the design case energy cost compared to the baseline case. They are included in the performance rating method (PRM) table or directly in the baseline and design case model.
Besides energy modeling, you may need to use the exceptional calculation methodology (ECM) when any of the following situations occur:
Some energy-modeling software tools have a daylight-modeling capability. Using the same model for both energy and IEQc8.1: Daylight and Views—Daylight can greatly reduce the cost of your modeling efforts.
Provide a copy of the AEDG for office, retail, or warehouse, as applicable, to each team member as everyone, including the architect, mechanical and electrical engineers, lighting designer, and commissioning agents, are responsible for ensuring compliance. These are available to download free from the ASHRAE website. (See Resources.)
Find your climate zone before attempting to meet any detailed prescriptive requirements. Climate zones vary by county, so be sure to select the right one. (See the Documentation Toolkit for a list of climate zones by county.)
Develop a checklist of all requirements, and assign responsible team members to accomplish them. Hold a meeting to walk the team through the AEDG checklist for your project’s climate zone. Clarify specific design goals and prescriptive requirements in the OPR for EAp1: Fundamental Commissioning.
Early access to the AEDG by each team member avoids last-minute changes that can have cascading, and costly, effects across many building systems.
The AEDG prescriptive requirements include:
If your project team is not comfortable following these guidelines, consider switching to Option 1, which gives you more flexibility.
Although Option 2 is generally lower cost during the design phase than energy modeling, the compliance path is top heavy—it requires additional meeting time upfront for key design members.
Provide a copy of the New Buildings Institute Advanced Buildings: Core Performance Guide to each team member. The guide is available to download free from the NBI website. (See Resources.)
The guide provides practical design assistance that can be used throughout the design process.
Walk your team through the project checklist to clarify design goals and prescriptive requirements.
The guide provides an outline for approaching an energy-efficient design, in addition to a list of prescriptive measures. The first of its three sections emphasizes process and team interaction rather than specific building systems or features. Advise the owner to read through the guide in order to understand what is required of the architect and engineers.
Section 1 in the guide focuses on best practices that benefit the project during the pre-design and schematic design stages, such as analyzing alternative designs and writing the owner’s project requirements (OPR).
Section 2 of the Core Performance Guide describes architectural, lighting, and mechanical systems to be included. Section 3 is not required for EAp2 but includes additional opportunities for energy savings that can earn EAc1 points.
The guide mandates that your team develop a minimum of three different design concepts to select from for best energy use.
Though they can be a little daunting at first glance, a majority of the guide’s requirements overlap with other LEED credits, such as EAp1: Fundamental Commissioning, IEQp1: Minimum Indoor Air Quality Performance, and IEQc6.1: Controllability of Systems—Lighting Controls.
This compliance path is top-heavy due to upfront consultant time, but it provides adequate structure to ensure that your project is in compliance with the prerequisite requirements. For some projects it may be less expensive to pursue than Option 1.
The owner should now have finalized the OPR with the support of the architect, as part of the commissioning credits EAp1 and EAc3. The goals identified here will help your team identify energy-reduction and occupant-comfort strategies.
Consider a broad range of energy-efficiency strategies and tools, including passive solar, daylighting, cooling-load reduction, and natural ventilation to reduce heating and cooling loads.
Develop the basis of design (BOD) document in conjunction with your mechanical engineer and architect for EAp1: Fundamental Commissioning, noting key design parameters to help strategize design direction as outlined in the OPR.
The OPR and BOD serve the larger purpose of documenting the owner’s vision and your team’s ideas to meet those goals. The BOD is intended to be a work-in-progress and should be updated at all key milestones in your project. Writing the document gives you an opportunity to capture the owner’s goals, whether just to meet the prerequisite or to achieve points under EAc1.
Confirm that your chosen compliance path is the most appropriate for your project, and make any changes now. Following a review with the design team and owner, ensure that everyone is on board with contracting an energy modeler for Option 1 or meeting all the prescriptive requirements under Options 2 or 3.
Sometimes teams change from Option 1 to Options 2 or 3 very late in the design phase for various reasons including not realizing the cost of energy modeling. Making that change is risky, though: the prescriptive paths are all-or-nothing—you must comply with every item, without exception. Evaluate each requirement and consult with the contractor and estimator to ensure the inclusion of all activities within project management.
To avoid costly, last-minute decisions, develop a comprehensive, component-based cost model as a decision matrix for your project. The model will help establish additional cost requirements for each energy conservation measure. It will also illustrate cost reductions from decreased equipment size, construction rendered unnecessary by energy conservation measures, and reduced architectural provisions for space and equipment access. (See the Documentation Toolkit for an example.)
Use envelope design and passive strategies to reduce the heating and cooling loads prior to detailed design of HVAC systems. Passive strategies can reduce heating and cooling loads, giving the engineer more options, including smaller or innovative systems.
Load reduction requires coordinated efforts by all design members including the architect, lighting designer, interior designer, information-technology manager, and owner.
Involving facilities staff in the design process can further inform key design decisions, helping ensure successful operation and low maintenance costs.
Encourage your design team to brainstorm design innovations and energy-reduction strategies. This provides a communication link among team members so they can make informed decisions.
More energy-efficient HVAC equipment can cost more relative to conventional equipment. However, by reducing heating and cooling loads through good passive design, the mechanical engineer can often reduce the size and cost of the system. Reduced system size can save money through:
Review case studies of similar energy-efficient buildings in the same climate to provide helpful hints for selecting energy-efficiency measures. For example, a building in a heating-dominated climate can often benefit from natural ventilation and free cooling during shoulder seasons. (See Resources for leading industry journals showcasing success stories around the country and internationally.)
The relationship between first costs and operating costs can be complex. For example, more efficient windows will be more expensive, but could reduce the size and cost of mechanical equipment. A more efficient HVAC system may be more expensive, but will reduce operating costs. Play around with variables and different strategies to get the right fit for the building and the owner’s goals as stated in the OPR.
Review and confirm compliance with the mandatory requirements of all the relevant sections of ASHRAE 90.1-2007
Trust your project’s energy modeling task to a mechanical firm with a proven track record in using models as design tools, and experience with your building type.
Contract an energy modeling team for the project. These services may be provided by the mechanical engineering firm on the design team or by an outside consultant. Software used for detailed energy use analysis and submitted for final LEED certification must be accepted by the regulatory authority with jurisdiction, and must comply with paragraph G2.2 of ASHRAE Standard 90.1-2007. Refer to Resources for a list of Department of Energy approved energy-analysis software that may be used for LEED projects.
Design team members, including the architect and mechanical engineer at a minimum, need to work together to identify a percentage improvement goal for project energy use over the ASHRAE 90.1-2007-compliant baseline model. The percentage should be at least 10% to meet the prerequisite.
Plan on initiating energy modeling during the design process, and use it to inform your design—preferably executing several iterations of the design as you improve the modeled energy performance.
Ask the modeling consultant to develop an annual energy-use breakdown—in order to pick the “fattest” targets for energy reduction. A typical energy-use breakdown required for LEED submission and ASHRAE protocol includes:
Identify critical areas in which to reduce loads. For example, in a data center, the plug loads are the largest energy load. Small changes in lighting density might bring down the energy use but represent only a small fraction of annual energy use.
Don't forget that LEED (following ASHRAE) uses energy cost and not straight energy when it compares your design to a base case. That's important because you might choose to use a system that burns natural gas instead of electricity and come out with a lower cost, even though the on-site energy usage in kBtus or kWhs is higher. Generally you have to specify the same fuel in your design case and in the base case, however, so you can't simply switch fuels to show a cost savings
Explore and analyze design alternatives for energy use analyses to compare the cost-effectiveness of your design choices. For example, do you get better overall performance from a better window or from adding a PV panel? Will demand-control ventilation outperform increased ceiling insulation?
Simple, comparative energy analyses of conceptual design forms are useful ways to utilize an energy model at this stage. Sample scenarios include varying the area of east-facing windows and looking at 35% versus 55% glazing. Each scenario can be ranked by absolute energy use to make informed decisions during the design stage.
If your project is using BIM software, the model can be plugged into the energy analysis software to provide quick, real-time results and support better decisions.
Model development should be carried out following the PRM from ASHRAE 90.1-2007, Appendix G, and the LEED 2009 Design and Construction Reference Guide, Table in EAc1. In case of a conflict between ASHRAE and LEED guidelines, follow LEED.
Projects using district energy systems have special requirements. For EAp2, the proposed building must achieve the 10% energy savings without counting the effects of the district generation system. To earn points in EAc1 you can take advantage of the district system’s efficiency, but you have to run the energy model again to claim those benefits (see EAc1 for details).
While you could run the required energy model at the end of the design development phase, simply to demonstrate your prerequisite compliance, you don’t get the most value that way in terms of effort and expense. Instead, do it early in the design phase, and run several versions as you optimize your design. Running the model also gives you an opportunity to make improvements if your project finds itself below the required 10% savings threshold.
The baseline model is the designed building with mechanical systems specified in ASHRAE 90.1-2007, Appendix G, for the specific building type, with a window-to-wall ratio at a maximum of 40%, and minimally code-compliant specifications for the envelope, lighting, and mechanical components. It can be developed as soon as preliminary drawings are completed. The baseline is compared to the design case to provide a percentage of reduction in annual energy use. To avoid any bias from orientation, you need to run the baseline model in each of the four primary directions, and the average serves as your final baseline figure.
The design-case is modeled using the schematic design, orientation, and proposed window-to-wall ratio—¬the model will return design-case annual energy costs. Earn points by demonstrating percentage reductions in annual energy costs from the design to the baseline case. EAp2 is achieved if the design case is 10% lower than the baseline in new construction (or 5% less in existing building renovations).
Provide as much project and design detail to the modeler as possible. A checklist is typically developed by the energy modeler, listing all the construction details of the walls, roof, slabs, windows, mechanical systems, equipment efficiencies, occupancy load, and schedule of operations. Any additional relevant information or design changes should be brought to the modeler’s attention as soon as possible. The more realistic the energy model is, the more accurate the energy use figure, leading to better help with your design.
Invite energy modelers to project meetings. An experienced modeler can often assist in decision-making during design meetings, even without running complete models each time.
All known plug loads must be included in the model. The baseline and design-case models assume identical plug loads. If your project is deliberately attempting to reduce plug loads, demonstrate this by following the exceptional calculation method (ECM), as described in ASHRAE 90.1-2007, G2.5. Incorporate these results in the model to determine energy savings.
For items outside the owner’s control—like lighting layout, fans and pumps—the parameters for the design and baseline models must be identical.
It can take anywhere from a few days to a few weeks to generate meaningful energy modeling results. Schedule the due dates for modeling results so that they can inform your design process.
Review the rate structure from your electrical utility. The format can inform your team of the measures likely to be most effective in reducing energy costs, especially as they vary over season, peak load, and additional charges beyond minimum energy use.
Performing a cost-benefit analysis in conjunction with energy modeling can determine payback times for all the energy strategies, helping the iterative design process.
Using energy modeling only to check compliance after the design stage wastes much of the value of the service, and thus your investment.
The architect and mechanical engineer should carefully read the applicable ASHRAE Advanced Energy Design Guide for office, warehouse, or retail projects, as applicable.
Keep the owner abreast of the design decisions dictated by the standard. Fill in the team-developed checklist, within the climate zone table’s prescribed requirements, with appropriate envelope improvements, system efficiencies, and a configuration that meets the standard requirements.
As a prescriptive path, this option relies heavily on following the requirement checklist, which is used throughout the design process to track progress. To assist design development, provide all critical team members—not limited to the architect, mechanical and electrical engineers, and lighting designer—with a checklist highlighting their appointed tasks.
The architect, mechanical engineer, and lighting designer need to discuss each requirement and its design ramifications. Hold these meetings every six to eight weeks to discuss progress and make sure all requirements are being met.
Confirm that your project team is comfortable with following all the prescribed requirements. If not, switch to Option 1: Whole Building Energy Simulation.
The LEED Online credit form does not specify how to document each prescriptive requirement because they are so different for each project; it only requires a signed confirmation by the MEP for meeting AEDG requirements. You still have to provide documentation. Submit your checklist of requirements, and supporting information for each item, through LEED Online to make your case. If your project fails to meet even one requirement, it will fail to earn the prerequisite, thus jeopardizing LEED certification.
Although energy modeling consultant costs are avoided by this option, additional staff time will be required to document and track compliance status, as compared with conventional projects.
Energy efficiency measures prescribed by the guide can be perceived as additional costs in comparison with conventional projects. However, they are easy to implement and are cost-effective pn the whole.
Become familiar with the Core Performance Guide early in the design phase to know the multiple requirements and all requisite documents.
Note that the guide demands additional time, attention, and integrated process from the design team as compared to conventional projects. It’s not just a list of prescriptive requirements, but a prescribed process for achieving energy efficiency goals. LEED Online documentation requires proof of all steps outlined in Sections 1 and 2, including three conceptual design options and meeting minutes. The project manager, architect, and mechanical engineer should read the complete Core Performance Guide carefully to know beforehand the prescriptive requirements in Sections 1 and 2.
The project manager must take responsibility for ensuring that the requirement checklist is on track.
For Section 3, the design team needs to identify three or more of the listed strategies as possible targets for the project.
Create a checklist of requirements and assign a responsible party to each item.
The Core Performance Guide requires an integrated design contributed by the architect, mechanical and electrical engineers, and lighting designer. The project manager must take responsibility for shepherding and documenting the collaborative process to demonstrate compliance.
A long documentation list can be overwhelming for your team, so create a detailed checklist with tasks delegated to individual team members, allowing each member to focus on assigned tasks. The checklist can function as a status tracking document and, finally, the deliverable for LEED Online.
The architect and engineer, and other project team members, continue to develop a high-performance building envelope with efficient mechanical and lighting systems.
Constant communication and feedback among project team members, owner, and if possible, operational staff, during design development can minimize construction as well as operational costs and keep your project on schedule.
If you change or go through value-engineering on any specifications, such as the solar-heat gain coefficient of glazing, for example, be aware of impacts on mechanical system sizing. Making changes like this might not pay off as much as it first appears.
Consider using building information modeling (BIM) tools to keep design decisions up to date and well documented for all team members.
Schedule delays can be avoided if all team members share their ideas and update documents during the design development process.
The modeler completes the energy analysis of the selected design and system and offers alternative scenarios for discussion. The modeler presents the energy cost reduction results to the team, identifying the LEED threshold achieved.
It’s helpful for the energy modeling report to include a simple payback analysis to assist the owner in making an informed decision on the operational savings of recommended features.
The architect and HVAC engineer should agree on the design, working with the cost estimator and owner.
Demonstrating reductions in non-regulated loads requires a rigorous definition of the baseline case. The loads must be totally equivalent, in terms of functionality, to the proposed design case. For example, reducing the number of computers in the building does not qualify as a legitimate reduction in non-regulated loads. However, the substitution of laptops for desktop computers, and utilization of flat-screen displays instead of CRTs for the same number of computers, may qualify as a reduction.
Residential and hospitality projects that use low-flow showers, lavatories, and kitchen sinks (contributing to WEp1) benefit from lower energy use due to reduced overall demand for hot water. However, for energy-savings calculations, these are considered process loads that must be modeled as identical in baseline and design cases, or you have the choice of demonstrating the savings with ECM for process loads.
Perform daylight calculations in conjunction with energy modeling to balance the potentially competing goals of more daylight versus higher solar-heat gain resulting in high cooling loads.
If your project is pursuing renewable energy, the energy generated is accounted for by using the PRM. These results provide information about whether the energy is contributing to EAc2: Onsite Renewable Energy.
A cost-benefit analysis can help the owner understand the return on investment of big-ticket, energy-conserving equipment that lowers operating energy bills with a quick payback.
Complete at least half of the energy modeling effort by the end of the design development stage. Help the design team to finalize strategy through intensive, early efforts in energy modeling. Once the team has a design direction, the modeler can develop a second model during the construction documents phase for final confirmation.
If pursuing ECM for non-regulated loads, calculate energy saving for each measure separately if you are, for example, installing an energy-efficient elevator instead of a typical one so that the reduction would contribute to total building energy savings. Calculate the anticipated energy use of the typical elevator in kBTUs or kWh. Using the same occupancy load, calculate the energy use of the efficient elevator. Incorporate the savings into design case energy use within the PRM. Refer to the ECM strategy for detailed calculation guidelines.
Ensure that all prescriptive requirements are incorporated into the design by the end of the design development stage.
Revisit the Advanced Energy Design Guides (AEDG) checklist to ensure that the design meets the prescriptive requirements.
The mechanical engineer, lighting consultant, and architect revisit the checklist for an update on the requirements and how they are being integrated into the design. All prescriptive requirements should be specifically incorporated into the design by the end of the design development phase.
The mechanical engineer and architect track the status of each requirement.
While the LEED Online credit form does not require detailed documentation for each Core Performance Guide requirement, it is important that each item be documented as required and reviewed by the rest of the team to confirm compliance, especially as further documentation may be requested by during review. Your design team should work with the owner to identify cost-effective strategies from Section 3 that can be pursued for the project.
Construction documents clearly detail the architectural and mechanical systems that address energy-efficiency strategies.
Confirm that specifications and the bid package integrate all equipment and activities associated with the project.
If the project goes through value engineering, refer to the OPR and BOD to ensure that no key comfort, health, productivity, daylight, or life-cycle cost concerns are sacrificed.
During the budget estimating phase, the project team may decide to remove some energy-saving strategies that have been identified as high-cost items during the value-engineering process. However, it is very important to help the project team understand that these so-called add-ons are actually integral to the building’s market value and the owner’s goals.
Removing an atrium, for example, due to high cost may provide additional saleable floor area, but may also reduce daylight penetration while increasing the lighting and conditioning loads.
Although this prerequisite is a design-phase submittal, it may make sense to submit it, along with EAc1, after construction. Your project could undergo changes during construction that might compel a new run of the energy model to obtain the latest energy-saving information. Waiting until the completion of construction ensures that the actual designed project is reflected in your energy model.
Create a final energy model based completely on construction document drawings—to confirm actual energy savings as compared to ASHRAE 90.1-2007 requirements. An energy model based on the construction documents phase will provide realistic energy-cost savings and corresponding LEED points likely to be earned.
Make sure the results fit the LEED Online credit form requirements. For example, the unmet load hours have to be less than 300 and process loads will raise a red flag if they’re not approximately 25%. If any of the results are off mark, take time to redo the model. Time spent in design saves more later on in the LEED review process.
Finalize all design decisions and confirm that you’ve met all of the prescriptive requirements. Your team must document the checklist with relevant project drawings, including wall sections, specifications, and the MEP drawing layout.
Value engineering and other factors can result in design changes that eliminate certain energy features relevant to the prerequisite. As this compliance path is prescriptive, your project cannot afford to drop even one prescribed item.
Value engineering and other factors can result in design changes that eliminate certain energy features relevant to the credit. As this compliance path is prescriptive, your project cannot afford to drop even one listed item. Although perceived as high-cost, prescriptive requirements lower energy costs during operation and provide a simple payback structure.
The architect and mechanical engineer review the shop drawings to confirm the installation of the selected systems.
The commissioning agent and the contractor conduct functional testing of all mechanical equipment in accordance with EAp1: Fundamental Commissioning and EAc3: Enhanced Commissioning.
Find your Energy Star rating with EPA’s Target Finder tool if your building type is in the database. Input your project location, size, and number of occupants, computers, and kitchen appliances. The target may be a percentage energy-use reduction compared to a code-compliant building, or “anticipated energy use” data from energy model results. Add information about your fuel use and rate, then click to “View Results.” Your Target Finder score should be documented at LEED Online.
Plan for frequent site visits by the mechanical designer and architect during construction and installation to make sure construction meets the design intent and specifications.
Emphasize team interaction and construction involvement when defining the project scope with key design team members. Contractor and designer meetings can help ensure correct construction practices and avoid high change-order costs for the owner.
Subcontractors may attempt to add a premium during the bidding process for any unusual or unknown materials or practices, so inform your construction bidders of any atypical design systems at the pre-bid meeting.
The energy modeler ensures that any final design changes have been incorporated into the updated model.
Upon finalizing of the design, the responsible party or energy modeler completes the LEED Online submittal with building design inputs and a PRM result energy summary.
Although EAp2 is a design phase submittals, it may make sense to submit it (along with EAc1) after construction. Your project could undergo changes during construction that might require a new run of the energy model. Waiting until the completion of construction ensures that your actual designed project is reflected. On the other hand, it gives you less opportunity to respond to questions that might come up during a LEED review.
Include supporting documents like equipment cut sheets, specifications and equipment schedules to demonstrate all energy efficiency measures claimed in the building.
It common for the LEED reviewers to make requests for more information. Go along with the process—it doesn’t mean that you’ve lost the credit. Provide as much information for LEED Online submittal as requested and possible.
The design team completes the LEED Online documentation, signing off on compliance with the applicable AEDG, and writing the narrative report on the design approach and key highlights.
During LEED submission, the project team needs to make an extra effort to support the prerequisite with the completed checklist and the required documents. Although the LEED rating system does not list detailed documentation, it is best practice to send in supporting documents for the prescriptive requirements from the AEDG. The supporting documents should include relevant narratives, wall sections, mechanical drawings, and calculations.
Although the LEED Online sign-off does not include a checklist of AEDG requirements, it assumes that the team member is confirming compliance with all detailed requirements of the guide.
The design team completes the LEED Online credit form, signing off on compliance with the Core Performance Guide, and writing the narrative report on the design approach and key highlights.
During LEED submission, your project team needs to make an extra effort to support the prerequisite with the completed checklist and the required documents. Although not every requirement may be mentioned in the LEED documentation, the supporting documents need to cover all requirements with narratives, wall sections, mechanical drawings, and calculations.
Many of this option’s compliance documents are common to other LEED credits or design documents, thus reducing duplicated efforts.
Develop an operations manual with input from the design team in collaboration with facility management and commissioning agent if pursuing EAc3: Enhanced Commissioning.
The benefit of designing for energy efficiency is realized only during operations and maintenance. Record energy use to confirm that your project is saving energy as anticipated. If you are not pursuing EAc5: Measurement and Verification, you can implement tracking procedures such as reviewing monthly energy bills or on-the-spot metering.
Some energy efficiency features may require special training for operations and maintenance personnel. For example, cogeneration and building automation systems require commissioning and operator training. Consider employing a trained professional to aid in creating operation manuals for specialty items.
Energy-efficiency measures with a higher first cost often provide large savings in energy use and operational energy bills. These credit requirements are directly tied to the benefits of efficient, low-cost operations.
Excerpted from LEED 2009 for New Construction and Major Renovations
To establish the minimum level of energy efficiency for the proposed building and systems to reduce environmental and economic impacts associated with excessive energy use.
Demonstrate a 10% improvement in the proposed building performance rating for new buildings, or a 5% improvement in the proposed building performance rating for major renovations to existing buildings, compared with the baseline building 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.
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 220.127.116.11.
Also, how does this apply to the apartment units themselves? Thanks.
I agree that the hallway lighting would meet exception a and c of 18.104.22.168.
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?
I ran into a similar situation with a v4 project. There are more space types in 90.1-2010 that make more sense for sports facilities like that, such as separating the audience seating area from the court sports. We were also able to apply the room cavity ratio adjustments. Maybe see if they would allow you to use those parts from 90.1-2010.
I disagree with the regulation of this lighting.
1. I think the baseline is 2.3 W/sf for court sports area under Sports Arena and this lighting is regulated and therefore not a process load. Lighting in the media room for cameras is probably not-regulated and is a process load.
2. You can't get an exception for excluding any energy use associated with the project. It is either regulated or not, if not it is a process load and must be included. You must meet the minimum savings or you can't earn LEED certification.
3. There is no exception.
The good news is that you can go over the interior lighting power density and show a negative savings for lighting (this is not mandatory). You will just have to make up for it elsewhere.
I'm glad you caught that. I also think it is regulated as a sport arena, but not the playing field space itself...right? Obviously as a building method it is regulated.
The court area (badmiton, basketball, volleyball, etc.) is included in this allowance under space-by-space at 2.3 W/sf. If it was a play field (football) the allowance is 1,.4 W/sf. The seating area would be separate at 0.4 W/sf under audience seating for a sports arena. The office would be 1.1 W/sf and the media room is probably multipurpose at 1.3 W/sf for the general illumination system and the camera lights are process.
Ah yes. I turned the page and there it was. You have persuaded me and jogged my rotten memory.
But let me consider a new angle. This applies to general lighting right? Can I claim that general lighting is different from the event lighting and consider the event lighting as a process load? So when there's no one playing and they're doing setup or cleaning or whatever, general lighting is on. But when the TV broadcasting starts the event lighting goes on.
The background is that I have been involved in the planning of several Stadium Arena and Multipurpose Sports Halls and the connected lighting power is always huge. So in my mind there is a "industry baseline" here and 25 W/m2 just doesn't feature on the playing area.
I think the event lighting is included in the allowance. I would have to look in the IES Handbook to be sure as they provide the illumination guidance that coincides with the W/sf allowance in 90.1. I could be wrong and this could be a gray area.
I am working on a project that has two parts to the building. There is an office component and a shop component. The office is going to be heated and cooled with a VRF system. The shop will not be air conditioned but will just be heated 100% from a waste oil burner. The oil is used from the trucks that they use at the facility.
Does anybody have any experience with something like this? How is this handled regarding energy modeling, etc.? The cost of the fuel should be 100% associated with the trucks that used the fuel. The shop portion of the building is getting the benefit of zero cost fuel.
Any guidance would be greatly appreciated. We are also thinking of applying for an innovation credit.
You need to use the same fuel and rate in both models. If the fuel cost is zero in the proposed it is zero in the baseline. If the cost is the cost of the motor oil then that cost must be identical. You can't derive a benefit in LEED from burning waste oil.
It is not eligible for an innovation credit either as there is no environmental or human health benefits from burning waste oil. Its highest and best use it to recycle it back into motor oil.
More generally, you cant show savings by fuel switching. Only way to get credit would be to classify the waste oil as renewable, and treat it as you might a biofuel. But as Marcus said, waste oil is not generally considered renewable, and the reviewers are not likely to accept that approach.
I'm working on a project where an existing building is being renovated but there is also a smaller new addition extending the building. When figuring out how many points we get for energy savings, we look in the table that has Existing Building and New Building columns, does LEED NC automatically put us in the New Building column? Or does the fact that a majority of the project area is renovation allow us to use the Existing Building column?
The EAp2 form will automatically calculate revised point thresholds base on the ratio of new to existing building area. So if you have a small addition your threshold will be closer to the new threshold than the existing. The formula used for each point is as follows:
existing % threshold + (new area % x (new % threshold - existing % threshold)) = adjusted % threshold
For example, if your project is 15% new construction - 5% + (15% x (10% - 5%)) = 5.75% this then becomes your minimum for meeting the prerequisite and the points would start at 8.6% following the same formula for the first point. After that is each point is in increments of 2% (10.6%, 12.6%, etc.).
We are doing a project that is a renovation and addition. Renovation of existing HVAC and addition of a gym as part of the same building (This area requires new MEP). Anyways, the existing area has lighting existing to remain, so I was wondering should both the baseline and proposed used the same existing lighting wattage (with NO savings)? If that's the case, table 1.4 updated on January 2014 does not seem to give the option to show existing wattage.
You are correct the existing lighting should be modeled identically. You will need to overwrite the information in Table 1.4.3A or add a note to the spreadsheet.
We have a culinary school with many kitchen hood exhaust, I wonder if the hood exhaust fan can be considered as process energy instead of regulated fan energy.
If that is the sole purpose of the unit, then yes it is a process load.
Is this new compliance path likely to have any effect, direct or indirect, on prereq/credit documentation?
I think it will eventually.
This is a new compliance path for demonstrating code compliance with 90.1 so it will eventually bring together code compliance and LEED documentation within the same methodology. That probably won't happen until states start to adopt 90.1-2016 which is not yet out. It will be a year or two at least and then only in the very few states that automatically adopt the latest version of the standard. Most states don't do so.
In order to work for LEED documentation the USGBC would need to develop the appropriate thresholds for percent savings relative to this new baseline. This also fixes a firm baseline so LEED 2009 projects, v4 projects and future LEED projects will be comparable to this baseline.
It will also hopefully get net zero on the scale for awarding points within LEED so that they can be appropriately awarded. Right now something like 50% better than 90.1-2007 earns all the EAc1 points available. If you get to 100% there is no additional reward within the point system.
This is a good step in the right direction.
Great! Thanks for explaining!
Hello, we are considering attempting the exceptional calculation method allowed in Section G2.5 for process load savings on a hospital project: the design is proposing equipment sterilization through central steam generation using fossil fuel boilers or heat recovery from power generators,
Can we take a baseline case that uses electrical power for sterilization, or it is not allowed that the baseline and proposed case have 2 different energy types?
I think you might be required to use the Healthcare version of LEED and this is an NC forum.
That aside, for all exceptional calculations related to claiming process load savings it is the responsibility of the project team to justify the baseline used for comparison. It should be based on standard industry practice for a hospital in your location. So if almost every comparable new hospital uses electric sterilization as the norm you may be able to use it as a baseline. However ASHRAE 90.1 does not allow savings related to fuel switching so you would likely need to make a pretty compelling case to claim savings related to fuel switching alone.
Based on the limited information provided I would say that the likelihood of being able to claim savings related to fuel switching alone is very low.
Thank you for your response, the savings are not only due to fuel switching but rather to the central steam network provided by a central plant (in replacement of sterilization equipment producing their own steam via electrical power). But as you said, even if the suggested baseline is accepted, it is not sure we can claim savings since the 2 systems are not using the same fuel type, and it is not allowed to claim savings related to fuel switching. Is there any Section of ASHRAE 90.1 or other reference document that you recommend to read for more guidance on those cases where savings are not only related to fuel switching?
I had posted on NC forum since I thought it was not only related to LEED for Healthcare but a more general question, thanks for the advice.
I had urged USGBC to publish some additional guidance for projects attempting to claim process load savings when I was chair of the EA TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system.. As far as I know nothing has been published. Specifically regarding fuel switching within 90.1 I again am not aware of anything in writing but there are some overall guiding principles associated with it development that I have read about over the years and fuel switching savings is an issue I have heard but again don't have a specific citation for you.
I may have helped you, now it's your turn to help us all.
The USGBC is seeking input and information related to the modeling of naturally ventilated and naturally conditioned buildings.
The currently accepted LEED methodology for claiming natural ventilation/conditioning savings has the following requirements. It is fully explained in the Advanced Energy Modeling Guide for LEED Technical Manual, Appendix D.1.
- The software must be able to directly model natural ventilation (EnergyPlus, IES-VE, etc.)
- Perform a comparative thermal comfort model to demonstrate similar comfort levels comparing mechanical to natural ventilation.
- Compare mechanical to natural ventilation only during met load hours. During unmet load hours it compares like systems (mechanical to mechanical or natural to natural).
The goal is to be able to offer project teams a simpler, sanctioned energy modeling methodology(s) to enable projects to claim energy savings related to natural ventilation/conditioning. The methodology should enable the use of all commonly used modeling software (DOE2, Trace, HAP, etc.) for estimating these energy savings. It should also likely enable projects to expand the acceptable thermal comfort comparison so projects can claim some savings for adaptive thermal comfort strategies.
We are differentiating between naturally ventilated, a la ASHRAE 62.1, and naturally conditioned or naturally cooled projects. Some thoughts on both are included below.
A modeling protocol could be developed which makes project teams aware that credit is available for fan savings in naturally ventilated spaces. 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 modeling protocol should be more straightforward than the existing protocol. As required by ASHRAE 90.1-2010 Appendix G Table G3.1-1Proposed (a), the proposed case should reflect the building design, however, different temperature and humidity control setpointsSetpoints are normal operating ranges for building systems and indoor environmental quality. When the building systems are outside of their normal operating range, action is taken by the building operator or automation system. could be allowed between the proposed and baseline case . Appropriate methodologies could include work arounds for specific software that produce conservative estimates of savings. The protocol should also address regularly occupied spacesRegularly occupied spaces are areas where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. which are not fully enclosed (typically in warmer climates). In order to develop a viable modeling protocol some additional modifications to the baseline requirements may also be necessary for various climates and situations. The baseline thermal comfort settings could reflect the project’s locations as the normal, acceptable conditions will vary in different cultures.
We are in the process of gathering information and suggestions on how best to accomplish these goals. We are seeking existing modeling protocols that have already been published (such as for utility incentive programs or other research) and your good ideas for how to address these issues. Please send links and ideas to my attention - email@example.com. Thanks.
I am very, VERY happy to see this subject. I am down right extatic to see that your discription shows you really know the issues and understand the basics.
Unfortunately, I don't like natural ventilation in terms of sustainable buildings. That being said, we will still have buildings (and future buildings) where the windows are used to ventilate and or cool (again, very happy this is distiguished as seperate issues).
I have written a paper on the subject that you can find here: http://www.ibpsa.org/proceedings/bausimPapers/2014/p1118_final.pdf
(caviat...there is a small error in one of the formulas...for questions, contact me directly - firstname.lastname@example.org)
Working with Dr. Gu, he has since then enabled a simplified version of occupant comfort driven window operation, based on the most important comfort factor (thermal comfort) which is available now in energyplus v8.4 as part of the AirFlowNetwork modules.
Other software to include this kind fuctionallity out of the box is IDA ICE. There may be others be now as well.
bottomline: I'll only accept designed naturally ventilated or cooled concepts if I can adiquately simulate that acceptable comfort levels can be maintained over the year. 90.1 keeps banking on unmet load hours. I believe discomfort hours is a better metric for this. And capturing those hours on a minute by minute basis may be required to catch the actual effects (see paper).
If you design it right, it can work...but in most cold climates the lost potential of heat recovery from mechanical ventilation simply can't be beat for enery savings.
Our Project have CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. (2 CNG Generator 500Kw with VAM Chillier 100TR)
what is rate we use for BASE Case and Design Case
For Design case we use the Fuel(CNG) cost invested to run a Generator to create Electricity
Which rate can we use for Base case
as per LEED Reference guide the Back up energy or Electricity cost may be considered as base case cost but I have a doubt in that base case cost arriving
1.we use diesel generator for Electricity back up can we arrive the electrical cost consumption using the specific fuel consumption from catalogue
But the cost of electricity is varying for both a cases because of the Specific fuel consumption of CNG Generator, Diesel Generator.
Can we take this advantage IN energy Simulation
As per this energy rates variation we get 20 - 25% saving can we claim this saving as a benefit of CHP.
is it acceptable manner
Awaiting for your reply
Samy, please see our FAQ on forum etiquette. Thanks!
The rate used for the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. in the proposed must be identical to the rate used in the baseline. You can't use the diesel rate for the baseline.
I am Currently working in a project aiming for certification under group certification. I am using DES V2 guideline and opting option 1. while modelling the proposed parameters, i am facing the following issues. Any response for these quires will be very help full.
1. As per option 1 - I need to model Downstream equipments only which means, that i can model only secondary pump with 11 W/GPM (CHW pumps). There is no need to model chillers, primary pumps and cooling towers as it is not required to model the upstream equipments. Is my interpretation is correct?
2. the whole site is using 2 secondary chilled water pumps serving 4 buildings in the site. Is there any methodology to model the proposed secondary chilled water pump?. these 4 buildings are of various size and height and the pump power should be modelled as per the actual requirement.is there any method or options available to model(segregate the pump power or heat of these 2 pump for these 4 buildings) these pumps?
3. Is ASHRAE specifies any methodology to model or calcualte the pump powder under these circumstances?
Appriciate prompt reply.
1. That sounds correct assuming there are pumps inside the building.
2. If you have pumps inside the building dedicated to that building alone then they are downstream. Anything outside the building, serving other buildings is upstream.
3. Proportionally but it sounds like you should not be modeling these pumps.
Again, based on your response for my questions, please confirm my understanding on modeling pumps for this project. The Project consists of 4 building out of which 2 buildings are aiming for Certification following Group certification process. there is a chiller plant in the utility building which houses all the chillers and associated pumps. this Utility building is not going for any certification. So, I am going with DES procedure opting option - 1 Stand alone scenario(Cost Neutral with modeling only Downstream equipments). since all these 4 Buildings served by that Chiller plant in the Utility building, none of the pumps are there inside those two buildings which are aiming for certification. So, In this case please let me know whether my modeling methodology is correct or not.
1. As there are no pumps in those two buildings aiming for certification, there is no need to model the pumps in proposed case. Am I Correct?
2. Is it possible to model a chilled water loop without a pump in energy analysis. we can delete the chiller and put a BTUA unit of energy consumed by or delivered to a building. A Btu is an acronym for British thermal unit and is defined as the amount of energy required to increase the temperature of 1 pound of water by 1 degree Fahrenheit, at normal atmospheric pressure. Energy consumption is expressed in Btu to allow for consumption comparisons among fuels that are measured in different units. meter but without chilled water pumps we cannot model the HVAC part.
3. If i am not modeling the pumps in the proposed case, my energy consumption of the pumps in the proposed case will be zero. am I correct?
4. If there is no pumps in the proposed design, what about the pumps in the base line? No need to model pumps in baseline (or) i need to model(what will be the W/Gpm)
5. If there is no Pumps in the proposed design, what should i enter in Table 1.4 for pumps? Can i write, 'Pumps are part of the Upstream so not applicable'?
Thanks for your time. Appriciate prompt reply.
1. Correct and no pumps in the baseline either. You are treating the chilled water as purchased energy.
2. It should be possible. Again treating the chilled water as purchased energy.
4. No pumps.
I am Energy Modeling a highrise new construction in NYC. The building total area is 150,000 SF but the nonresidential areas combined are more than 20,000 SF therefore the building complies with G.1.1 exception (a).
I used System 1 for the residential portion of the building 90,000 SF
Question: I am not sure if the nonresidential areas (28,000 SF combined) should be considered for system 7 since the building is over 5 floors or I deal with them individually where none of them is more than 25,000 SF or more than 3 floors so all will use system 3.
Thanks for help in advance.
I'm confused by your numbers. When you subtract the residential you should have 60,000 sf. This would be a system 5.
Thank you for your response Marcus.
Actually out of the 60,000 sf there's (16,000 sf Parking Garage, 12,000 Retail, 17,000 Church and the rest is common areas as corridors and stairs)
From your replied above I got that I should model the Residential 90,000 as system 1 and everything is as system 5. Correct me please if I am mistaken
In a residential high rise I would always include the corridors and stairs in the residential portion as that is the function they serve. If the parking garage is unconditioned it is excluded so now we have 29,000 sf. This is still a system 5. You then could apply G3.1.1 Exception b based on schedule differences and end up with a system #3 in the retail (the church area is greater and therefore predominant). At this point you probably have a choice. You could claim that you are now left with 17,000 sf and model a system 3 for the church as well or model the church as a system #5 and the retail as #3. Either way would probably be OK.
We are working on the certification of a building that will be connected to a DES using a CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. plant. The DES delivers to the building chilled and hot water for cooling, heating and DHWDomestic hot water (DHW) is water used for food preparation, cleaning and sanitation and personal hygiene, but not heating..
The DES has a 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. biomass plant (residue from city parks). The electricity produced is directly used into the DES. Actually the cogeneration system produces 3 times the whole electricity consumed by the plant, including chillers and circulation pumps consumption.
The thermal output of the cogeneration biomass plant is used within the DES to enhance the efficiency of the gas boilers that deliver hot water to the buildings.
The question is: do we have to follow the Appendix D of the 'Treatment of District or Campus Thermal Energy in LEED' guide?
From this guide and also from what is said in the reference guide EAc1 CASES 3 and 4. District CHP it seems that the electricity allocation for the building is related with the thermal output of the CHP. I think this would be restrictive in our case as the electricity output of the CHP covers all electricity needs of the DES plant.
We would appreciate any thought on this situation!
Where is the project located?
The project is in Spain, Barcelona
You are not required to follow that guidance as you can always use DESv2 Option 1 or 90.1-2007 Addendum ai. You will need to use some type of guidance to model your situation. Another option is this for European projects.
Marcus, thanks for your guidance. Instead of DESv2 Option 1, we are looking into DESv2 Option 2 in order to account for DES actual efficiencies. The DES we will be connected to includes a 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. plant producing heat, cold and electricity. The input energy of the DES is biomass and gas. The DES provides hot and cold water to its network of customers. The net electricity they produce is not sold to their customers but to a utility company.
The cogeneration plant consumes 28 units of biomass to produce 12 units of electricity and 9 units of heat. 4 units of electricity are consumed by the DES itself (for chillers to produce cold water and distribution pumps). The 8 remaining units of electricity are sold to the utility company. The heat is complemented with additional heat generated by a gas boiler using 4 units of gas and distributed as hot water to the clients. The DES distributes 12 units of hot water and 8 units of cold water to their clients.
We would like to use Option 2 of the DES guidelines. For this situation, the baseline would be modelled as per Appendix G with electricity for cooling and gas for heating.
According to the Option 2, DES guidelines, the proposed case will have the chillers and boiler of the DES plant and the cost of the produced energy is calculated as follows: cost of biomass divided by the total thermal outputs of the plant (cost of 28 units of biomass + 4 units of gas / (12+8 units of thermal outputs = $/kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu.).
If this is correct we are including energy inputs associated with the electricity sold to a third party (the utility). How do we take this into account?
Marcus, thank you for your guidance. In order to account for actual DES efficiencies, we are looking at DESv2 Option 2. The DES we will be connected to includes a 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. plant producing heat, cold and electricity. The input energy of the DES is biomass and gas. The DES provides hot and cold water to its network of customers. The net electricity they produce is not sold to their customers but to a utility company.
The cogeneration plant consumes 28 units of biomass to produce 12 units of electricity and 9 units of heat. 4 units of electricity are consumed by the DES itself (for chillers to produce cold water and distribution pumps). The heat is complemented with additional heat generated by a gas boiler using 4 units of gas and distributed as hot water to the clients. So, with 28 units of biomass and 4 units of gas, the DES distributes 12 units of hot water and 8 units of cold water to their clients while selling 8 units of electricity to the utility company.
According to Option 2 of the DES guidelines, the baseline would be modelled as per Appendix G with electricity for cooling and gas for heating.
For the proposed case, we simulate the chillers and boiler of the DES plant and the cost of the produced energy is calculated as follows: cost of biomass divided by the total thermal outputs of the plant (cost of 28 units of biomass + 4 units of gas / (12+8 units of thermal outputs = $/kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu.).
If this is correct we are including energy inputs associated with the electricity sold to a third party (the utility). How do we take this into account?
(cost of 28 units of biomass + 4 units of gas) / (12 units of hot water) = $/kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu. of fuel used to produce the hot water in the Proposed model
The 8 units of cold water are modeled as all electricity in the Proposed Case. The electricity produced by the cogen plant gets allocated to the building according to Appendix D of the DESv2. It does not matter how much electricity is used in the plant or sold to the utility.
We are working on the energy modeling for Industrial Manufacturing facility in which some places can be classified as “Semi heated spaces” as per ASHRAE 90.1 2007 definition. These semi heated spaces in our facility cater to some Industrial operations and are not exactly circulation service spaces like staircases, corridors etc. Also, there is a top-vent MH unit that is used to ventilate and heat the semi heated space. The unit heats fresh air in the heating coil and blows it into the room through a air –injector.
We would like to request some clarity on how to model this space in the baseline.
Our Initial understanding on this is that a "semi-heated" space is not a "conditioned space" per ASHRAE 90.1. Is it acceptable to model the space as unconditioned in the baseline and proposed models, and capture the semi-heating as neutral process energy? Or is there an alternative?
No it must be modeled as semi-heated. The insulation levels may change according to Table 5.5-X. The HVAC is modeled identical to the proposed system in the baseline.
We are currently working on an existing building under major renovation, pursing a LEED certification following NC protocol v.2009.
We have a doubt in relation to the table G.3.1.5.f requirements, regarding the reference thermal transmittance values of opaque elements and fenestration used for the existing baseline-building envelope construction:
Can the baseline model consider the above-mentioned performance values taken from a reference table issued by the National Energy Agency, reporting reference values and construction assemblies classified per age range and building use?
I don't think so but you might be able to make that case depending on the details. Hard to say for sure without knowing more about the situation. You really should determine the actual composition of the existing walls and calculate the assembly U-valueU-value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The greater the U-value, the less efficient the building element is as an insulator. The inverse of (1 divided by) the U-value is the R-value. accounting for the structure.
For a building with an elevation with 70% glazing and the others with less than 40%, how would the baseline elevations be modelled? Would the façade with 70% glazing be modelled with 40% glazing in the baseline and the other exactly as they are, or would all facades be modelled with proportionally reduced glazing so that in total (for all facades) glazing is 40% (although one facace may still exceed the 40% threshold)?
In other words, would the façade with 70% glazing be modelled in the baseline with 70% as well, if the total percentage of glazing for all facades does not exceed 40% (in total)?
See Table G3.1-5 Baseline (c). You distribute the 40% window area in the baseline model using the same proportions as the proposed design.
The way I like to think about it is surface for surface:
- If a proposed case surface has glazing on it more than 40%, then reduce that glazing on that surface in the baseline to 40%
- if a proposed case surface has glazing on it less than 40%, (this is true for both no glazing, i.e. zero or another percent like 38%), then the baseline is modeled EXACTLY the same
In practice this means that the total is often a bit less than 40%.
Thanks. That said, in case the total glazing (all facades) is less than 40%, no reduction is required even if one single facade may exceed 40% glazing.
On the other hand, in case the total glazing (all facades) exceeds 40%, the reduction will be proportional to all facades down to 40%, which means that even a single facade with less than 40% will be reduced by the same percentage as a facade exceeding 40%. Is that correct?
Looking in the Manual it says basically to reduce the m² for each and every window (above grade) by the same x% untill the total WWR of the (above grade) building is 40% or equal to the proposed case (as when the proposed case has less than 40%), whichever is smaller.
1. No baseline window may be larger than the proposed case window. It may be smaller.
We have a project that use heat recovery chiller to recovery heat from the waste heat from a nearby data center. The waste heat will preheat the outdoor air and the heat recovery chiller will provide the rest of the heating. So essentially all the heating is provided through waste heat and electricity used by the HR chiller. So should this project be considered using district heating or electricity? This will have really large impact on the baseline model. Thanks
If the heat source is not within the LEED project boundary and serves other facilities as well then it can be treated as district.
We are working on a project which falls under the category of System 6 - Packaged VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with PFP Boxes for the Baseline Building. The cooling system associated with this is "Direct Expansion" and you are referred to Section 6.4 for Efficiency Ratings/Levels.
In Section 6.4, it is not clear which equipment type corresponds to Packaged VAV with Direct Expansion? It appears that it could be from Table 6.8.1A, Table 6.8.1B or Table 6.8.1D. We believe the most representative system would be Table 6.8.1A Air Conditioners, Air Cooled (Package System).
Clarification on the above would be appreciated - thank you in advance!
I agree that these definitions are pretty murky. No, I don't think you are correct. See Table G3.1.1B...Package "terminal" units are system 1 and 2. The rest are all "rooftop" units. Whether the reheat occurs decentrally at the terminal (which is common in America) or centrally at the AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. is very unclear. However, in the USA these 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. terminal boxes are typically contain the reheat coil at the terminal (decentral). As they are also used to control the heating setpoint and not just to condition the air to say 22 C but used to heat by supplying air at up to 40 C (bear in mind for the baseline it must be Heating Setpoint + 11C and Cooling Setpoint - 11C), this makes sense.
DX means no chilled water, so you don't have a chiller.
Heating is electric, so no gas or oil
It's not a Vertical, Room or Terminal unit
DX is air cooled
As you have an electric heater, the DX is not a reversable HP, so not Table 6.8.1B either
That leave just Table 6.8.1A which applies to split AND single package systems. You have single package (split refers to the cooling dx coil being decentral as in the indoor units of a VRF system...again murky as this could also fit the system description, but VRF is not old and baseline enough, ha ha...again murky because the heating is split, ha ha).
As this is DX (air cooled), forget about water or evap cooled for equipment type. Then sort by kW and Heating Section Type.
To all those Americans reading this...I hope this offers a view into our world of confusion.
As Americans we expect everyone to know the vagaries of English and IP units and are equally confused when you don't! :-)
Despite the murkiness you have reached the right answer I think. Use Table 6.8.1A.
The project is a garment factory. We are modeling a 100% outdoor air IEC system for the proposed case. And the 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) is modeled in the baseline case. The IEC system provides a lot of outdoor air for the spaces. So can we model this supply outdoor air as the outdoor air of the baseline system? Beacause the outdoor air is too much, it causes a lot of energy consumption in the baseline system. This seems to be unreasonable.
The answer will depend on whether you have Exhaust Air Energy Recovery or not, and whether you have demand-control ventilation or not.
Please refer to ASHRAE 90.1 Sections 22.214.171.124, 126.96.36.199, G188.8.131.52, and G184.108.40.206.
The project is a garment factory. We are modeling a 100% outdoor air IEC system for the proposed case. And the 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) is modeled in the baseline case. The IEC system provides a lot of outdoor air for the spaces. So can we model this supply outdoor air as the outdoor air of the baseline system? Beacause the outdoor air is too much, it causes a lot of energy consumption in the baseline system. This seems to be unreasonable.
The quantity of outdoor air should be identical in both models (unless the proposed has demand controlled ventilation) based on the outside air in the proposed system design.
Our project is a multi-family residential project (8 stories) and we have modeled the baseline roof as a Residential, Insulation Above Deck U-ValueU-value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The greater the U-value, the less efficient the building element is as an insulator. The inverse of (1 divided by) the U-value is the R-value. per Table 5.5-1.
We have received a LEED Review Comment back stating that "Note that the residential area must comprise 60% or more of the space usage for this building in order for it to be classified as a residential facility. If the project cannot be classified as a residential facility based on the definition provided, revise the roof constructions in the Baseline model "
We have seen several opinions posted on LEED User in how to model Non/Resi Envelopes:
(1) To model all residential floors with Residential U-Values and to model all non-residential floors with non-residential u values
(2)To model all residential zones with Residential U-Values and to model all non-residential zones with non-residential u values
I have never seen this reference of 60% when discussing the classification of Non-resi/Resi U-Values. (I have combed through Addendum and CIRs). We have 59% of floor area devoted to the apartment units. The remaining area is corridors/ MER/ storage, amenities and based on the LEED Review comment would need to update our Baseline Roof to non-Residential.
Does anyone know if there is specific language in Appendix G or USGBC documentation which states how Non-Resi or Resi is determined?
Not sure where the 60% comes from. I don't see anything in your description that is nonresidential. Sounds like all residential to me. An example of a combination would be a building that has lower level retail or is a combaination of office and residential or a hotel with commercial space on the first floor, etc. If your building has a lobby and common area on the lower level and apartments then the whole building is residential.
For Appendix G the residential roof and walls should use the residential requirements from the 5.5-X tables and the nonresidential roof and walls should use the nonresidential requirements. Anything else makes no sense.
So if you have a high rise and the top floor is residential then you would have not nonresidential roof.
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