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 15% of the total available points in LEED are at stake. Master the minimum requirements under EAp2, and you will be well on your way to earning points under EAc1. Keep in mind that any LEED-NC v2.2 project registered after June 26, 2007 must achieve at least two energy use reduction points via EAc1 methodology. Plan for this in your approach to EAp2.
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.
All projects must meet all the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4, and 10.4) of ASHRAE/IESNA Standard 90.1-2004 (without amendments).
There are prescriptive compliance paths available for the prerequisite. However, all projects registered after June 2007 have to obtain two points under EAc1, which offers three compliance paths. You probably should choose a compliance paths that allows you to achieve both EAc1 and EAp2.
If energy modeling is not planned for the project, must meet either the prescriptive requirements (Sections 5.5, 6.5, 7.5, and 9.5) of ASHRAE 90.1-2004 (without amendments) or as selected for EAc1.
Energy modeling 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 90.1-2004 for all major components, including the envelope, HVAC, lighting, and domestic hot water. The best way to do is look up the list of mandatory requirements and fill the ASHRAE 90.1 compliance forms.
Second, you need to demonstrate energy cost savings as determined for EAc1 point goals for your designed building compared with a baseline case meeting the minimum requirements of ASHRAE 90.1. You can do this by creating a computer model following rules described in Appendix G of ASHRAE 90.1, or pursuing one of the other EAc1 compliance paths.
Computer modeling offers the following key advantages:
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 ASHRAE prescriptive compliance paths are a good way to earn the prerequisite simply by following a checklist.
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.
As a general rule that applies to all energy credits, 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.
If your building includes the use of purchased steam supplied to your HVAC system, the proposed (design) building should be modeled as if the steam system is “located” in the building—with the same efficiency with which it typically operates. The designed building is allocated only the fuel cost (for natural gas or oil) required to generate and deliver the steam needed for the building. The steam purchased is actually considered “free,” as steam rates are not included. And here is where your building really benefits—if the steam system also co-generates electricity along with steam, that electricity is assumed to be “free” to the proposed building, as well. (Refer to the latest guidelines from USGBC.)
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 big picture goals for the project 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.)
You will need to comply with the mandatory requirements of ASHRAE 90.1-2004, to bring your project to the minimum level of performance. The ASHRAE 90.1-2004 User’s Manual is a great resource, with illustrated examples of solutions for meeting the requirements.
Check the registration date of your project. If you registered after June 2007, you have to achieve two points under EAc1 as per USGBC addenda. There is lot of synergy between EAc1 compliance and meeting this prerequisite because of this reason. The prerequisite’s energy-reduction target (for EAc1 option 1) of 14% is not common practice and is considered beyond code compliance.
If you registered before 2007, you have a lower threshold and can follow the AHSRAE 90.1 2004 prescriptive compliance path. You do not technically have to earn any points in EAc1.
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.
Remember that the ASHRAE 90.1-2004 mandatory provisions and prescriptive and performance requirements are a starting point for energy efficiency. Plan to exceed these to earn points under EAc1.
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:
All compliance path options may require both the architectural and engineering teams to take some time in addition to project management to review the ASHRAE prescriptive checklists, fill out the LEED Online submittal template, and develop the compliance document.
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 in the Basis of Design.
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.
Load reduction requires coordinated efforts by all design members including the architect, lighting designer, interior designer, information-technology manager, and owner. While ASHRAE 90.1-2004 is a good starting point for this effort, don’t plan to stop there:
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:
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 reconfirm compliance with the mandatory requirements of all the relevant sections of ASHRAE 90.1-2004
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.
Of equal importance, make sure that any scope reductions or design changes don’t jeopardize meeting the ASHRAE 90.1-2004 requirements.
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 mechanical engineer, lighting consultant, and architect revisit the ASHRAE checklists 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 should track the status of each requirement on an on-going basis, through design iterations.
While the LEED Online submittal template does not require detailed documentation for each requirement, it is important that each item be documented in supporting documents and submitted to be reviewed by the rest of the team and the GBCI reviewer.
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.
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.
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.
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.
Most of the documentation for EAc1 is shared with EAp2. Don’t forget to document the mandatory provisions of ASHRAE 90.1 2004 for EAp2 compliance, however, because that will not requested in EAc1.
Excerpted from LEED for New Construction and Major Renovations Version 2.2
Establish the minimum level of energy efficiency for the proposed building and systems.
Design the building project to comply with both—
Design the building envelope, HVAC, lighting, and other systems to maximize energy performance. The ASHRAE 90.1-2004 User’s Manual contains worksheets that can be used to document compliance with this prerequisite. For projects pursuing points under EA Credit 1, the computer simulation model may be used to confirm satisfaction of this prerequisite.
If a local code has demonstrated quantitative and textual equivalence following, at a minimum, the U.S. Depart- ment of Energy standard process for commercial energy code determination, then it may be used to satisfy this prerequisite in lieu of ASHRAE 90.1-2004. Details on the DOE process for commercial energy code determi- nation can be found at www.energycodes.gov/implement/determinations_com.stm.
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 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.
A guide for achieving energy efficiency in new commercial buildings, referenced in the LEED energy credits.
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.
This website discusses the step-by-step process for energy modeling.
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.
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.
2008 guidelines and performance goals from the National Science and Technology Council.
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.
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 sample EAc1 LEED Online credit template shows documentation of a project using the California Title 24 energy code.
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.
This template is the flattened, public version of the dynamic template for this credit that is used within LEED-Online v2 by registered project teams. This and other public versions of LEED credit templates come from the USGBC website, and are posted on LEEDuser with USGBC's permission. You'll need to fill out the live version of this template on LEED Online to document this credit.
Documentation for this credit can be part of a Design Phase submittal.
We modeled our building using eQuest, from eQuest we get as simulation result the Building energy performance report BEPS and building utility performance report BEPU. The values in the BEPR for example are in MBtu, whereas the ones in the BEPU are in 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.. Which piece of information should be used to fill out the energy use in the templates?, from the unit conversion specified in LEED, the MBtu values when converter to kWh, are less than 1/1000 of the results in the BEPU. Are we doing the unit conversion wrong? should we just use the BEPR results and disregard the BEPU results?
Sounds like the conversion is off. Are you assuming 1000 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. or 1 million BTU?
I would recommend that you use the BEPU results for entering in the template.
I am working on a project with a limited site. The proposed building (six story hotel) has a distinct size that only fits on the site one way. How should I address Criteria 1.3: Building Configurations in order to pass the exploration of the alternate building configurations? Thanks.
I am working on a project that was denied EAp2 in final review due to a discrepancy in an exceptional calculation we provided. To summarize, we were having a hard time modeling the energy savings of ERV units in Energy Pro so we modeled the savings in excel separately. The reviewer pointed out that the energy savings of the ERVs was 89% of the total heating and cooling load of the building (which they believe is unlikely) and threw away the savings resulting in a total building energy savings of 8.5% and denial of EAp2. Upon investigating the entire building model we found that using the LEED module in Energy Pro (we had previously used the T24 module) the building performed 12.2% better WITHOUT modeling ERVs. I have also found a way to model ERVs, however it has no practical effect.
Regarding submitting an appeal, will LEED accept our revised energy model? What documents will I need to submit in order to ensure an open and shut acceptance of our appeal?
The exact opposite happened to one of my projects.
Exterior to the building process loads accounted for 95% of the total cost use. The energy cost savings for the ECMEnergy conservation measures are installations or modifications of equipment or systems intended to reduce energy use and costs. was about 38%.
The building without exterior process loads, but including building process loads, had an energy cost savings, also, of about 38%.
The reviewer challenged the ECM, but forced the project to keep the ECM. In your case they forced your project to remove it.
This type of game playing by reviewers does not surprise me. Why claim one project must keep an ECM, and another not, has no justification.
In our case the ECM was highly specialized. Only two engineering firms in the United States are qualified to design the systems. The LEED reviewer decided they were more qualified to determine what the ECM system design should be than either of the two qualified firms.
I would love to find out who the ECM reviewer was, to investigate what qualified them to design the ECMs, which were related to critical life-support of animal species. My guess, is they had no qualifications whatsoever. Yet, their opinion stood. The GBCI could do nothing about the review comment once the reviewer "invented" it.
I am sorry to say, that there is no way to know what the reviewers want for ECMs. It is a completely blind part of LEED Energy Analysis, one where reviewers can make up their own rules. Rules that are often wrong, but somehow become hardcore LEED requirements.
That there can be two completely different sets of LEED ECM requirements, it of great interest to me. That means the requirements are not applied evenly, or fairly, by the reviewers.
I assume that the LEED module is using 90.1- Appendix G. If everything is in order then there should be no reason the revised model would not be accepted. Be sure to include a thorough explanation of what you have done and provide the documentation requested. Make sure to examine the modeling results submitted for the final and the appeal and explain any major differences in the results and/or the inputs.
Thanks Marcus. I've now gone even deeper into the model and realized that Energy Pro models the incorrect baseline HVAC system. I would like to implement a work-around into the model to get it to model the correct baseline. The system is a VRF heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. and Energy Pro models it against a 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. while it should be modeled against a packaged heat pump since there is no gas available on site. There is an acceptable and published work around for modeling VRF systems for Title 24 compliance.
If you cannot speak to my specific case about the VRF system, can you please advise whether implementing a published acceptable work around in the energy model and resubmitting the appropriate documentation will be acceptable for an appeal?
I do not see anything in what you are suggesting that would unacceptable for an appeal.
Nevermind... Found an answer to my question.
42, the answer is always 42.
I am not sure to understand the G220.127.116.11 Equipment efficiencies of appendix G. My question is: for the system 4-PSZ-HP packaged rooftop heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source., Which table belongs the system 4 (among 6.8.1 tables)?
Thanks in advance.
It's not clear to me if the baseline geometry is allowed to be different from the proposed building geometry. (with the same area of floor, wall, roof and fenestration(if <40%), numbers of floors, exposed perimeters of concrete slabs on grade ...)
In order to transform an irregular floor area to a rectangular one.
The baseline geometry must be identical to the proposed. The only exception is the glazing area if the proposed is over 40% window to wall.
The Energy Cost Budget/PRM Summary indicates that the full load equivalent hours for interior fans in the Proposed and Baseline model are approximately 2,500 hours and 4,000 hours, respectively (determined from dividing the total energy consumption by the peak demand power for each model); however, it appears that this project is a 24-hour facility, and it is unclear if the HVAC fans are modeled as cycling to meet the cooling and heating loads of the building during unoccupied hours. Table G3.1.4 in the Proposed building column requires that HVAC fans that provide ventilation air in the Proposed model must be modeled as operating continuously during occupied hours and cycled to meet the cooling and heating loads of the building during unoccupied hours, unless one of the exceptions of Table G3.1.4 are met. In addition, Section G18.104.22.168 requires that supply and return fans reflected in the Baseline model must be modeled as operating continuously during occupied hours and cycled to meet the cooling and heating loads of the building during unoccupied hours, unless the operation of the fans is required to meet health and/or safety requirements during unoccupied hours. Therefore, the full load equivalent hours should be closer to 8,760 hours in each model if this project is operated as a 24-hour facility. Revise the Proposed and Baseline models, as needed, to meet the requirements of Table G3.1.4 in the Proposed building column and Section G22.214.171.124. If the full load equivalent hours for the fan operation in the Proposed or Baseline model remain low and this project is indeed a 24-hour facility, provide a supplemental narrative explaining the indicated modeling results. Ensure that all project operation schedules (occupancy, lighting, process loads, etc.) reflect the actual design.
My Modeling Fan cycling schedule is: Cycle with occupancy. Also although the building is 24 hr operation, schedule for the inmate inside the building is not 24 hr, they will go out of the building during the day time. Do I have to show 8,760 hr in each model. Is there criteria I have to consider.
You do not have to change it to 8760 hours unless you need to do so to comply with the Appendix G sections referenced in the comment. Do you meet one of the exceptions to G126.96.36.199? Thoroughly explain what you are doing and how it complies with the referenced Appendix G sections.
It appears as if the review comment tells you what criteria you must consider.
For couple of equipment which is heating only i met exception G3.1.4.a,
Is there a Fan Calculator for Ashrae 90.1-2004?
See the documentation toolkit tab above. The 2004 fan power calculations are on the first tab of that spreadsheet.
For base line building, Equipment capacity has been oversized by 15% for cooling and 25% for heating. Than i entered that value as cooling and heating capacity in cooling equipmentThe equipment used for cooling room air in a building for human comfort. and heating equipment. But the Leed review report read as " The Entered Value Plants report indicates that the cooling capacity and heating capacity has been user defined for each HVAC system in Baseline model; however section G188.8.131.52. requires that the cooling and heating capacity must be autosized in the Baseline model based on the building cooling and heating loads. Revise the packaged rooftop air conditioners in Baseline model to reflect autosized cooling and heating capacities".
My question is; Isn't that i am doing the same what the reviewer wants.
How did you size the baseline capacities? Typically it is auto-sized by the modeling software. If this is not the case explain how you sized it. If you did what the reviewer wants then just provide a thorough explanation.
Baseline capacities is sized by the software. Than i increased the sized by 15% for cooling and 25% for heating. Which then i input those value in Equipment capacities. Fox example from load calculation if the system load is 100 MBH for cooling, than i input 115 MBH as input capacity for equipment.
Is that correct. is the reviewer tying to explain different than this?
The reviewer sees the capacities as "user defined" in an input report. Again typically one would see "auto-sized" instead and an additional capacity entered as a percentage on the same report.
What you are doing sounds right however. Explain what you are doing to the reviewer including the calculations you are performing to determine the value you are entering in the software and provide input reports from the modeling software to back it up.
We are currently submitting documentation for a multifamily building located in a site with a parking garage and other three residential buildings that are not going for LEED rating. It is kind of hard to tell if the parking garage should be part of the LEED boundary or not since the parking serves all the residential buildings but we still would like to show energy saving by the installation of LED lights. We know that for the current rating (V3) the MPRs are very specific on this issue, but since the MPRs do not apply to V2.2. i would like to know what is the right way to proceed. Thanks.
It depends on where you draw the LEED Boundary. v2.2 was more flexible on this issue but the boundary still needs to make sense. Sounds like the garage is existing. Typically a portion of a shared existing parking garage would be included and then you could claim energy savings from that.
The garage is being built at the same time as our LEED building.
How about the other buildings?
Is it all one construction contract?
How does each particular boundary being considered affect the LEED checklist?
Too many questions would need to be answered to even guess at a proper boundary. Many of them have nothing to do with the energy scope.
Hello. We are currently working on a multifamily building with 5 stories. To create the baseline for the Energy Model, I dont know if in Appendix G it would fall under residential (System 1-2), or under " Non residential and 4 or 5 floors and <75000 SF or 5 floors or less & 75000 SF to 150000 SF (System 5-6). Thanks
Residential is always residential no matter how tall it is.
You could also check out LEED for Mid-Rise residential as it is specifically for residential building 4 to 6 stories.
Im not being able to find information on LEED for Mid-Rise residential from USGBC, can you tell me where to find it? Additionally, Im not sure if at this point would be able to change to this version (that seems to fit more accordingly to our project) and since v2.2 registrations are closed. Is there anything else we can work around that?
Hard to find this stuff on the new web site. Can anyone else point Victor to the general Mid-Rise information? Not sure about changing either.
Mid-Rise does follow these modeling guidelines - http://new.usgbc.org/resources/energy-star-multifamily-high-rise-simulat...
I am looking to validate our understanding of LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #2299.
The ruling states:
For EAp2, the cited exemption for meeting the requirements of Section 5-10 of ASHRAE 90.1-2004 applies to this project, provided that the project receives the designation, listing, or eligibility that is required by the exception.
The formal inquiry regarding EAp2 was only relative to exemption from Section 10, Building Envelope. However we are interpreting the ruling that a building listed in the National Historic Registry is exempt from meeting the requirements of Section 5-10 of ASHRAE 90.1-2004.
Is this correct ??
Based on Section 184.108.40.206 that appears to be the case. Projects on the Historic Register are given a blanket exception to the requirements of the standard in Section 5 through 10. This would include the mandatory provisions. The ruling is clear however that you must still demonstrate the required energy savings for LEED.
I'm working on a project where the design of the buildings includes little windows (40 cm x 20 cm) therefore PVC framing is not an option to comply with the max ASHRAE U Value because the glazing part would be really really small as the frame would be almost 3" each side, it doesn't even make sense to have a window. Not to talk about the price.
I was wondering if there is an exception for the mandatory values in ASHRAE for fenestration so I could use metal framing with or without thermal break without sacrificing the windows design.
Thank you in advance.
The window U-values are not mandatory. They are available for trade-off so design what makes sense.
It's no clear to me if the surrounding buildings can be modeled as permanent shading devices. Is it allowed to use the neighbours' shading on the proposed building in the energy simulation?
The current version of the standard does not allow you to model surrounding buildings. The 2010 version does but they are modeled identically in both the baseline and proposed. It does not make any sense to allow this type of shading for the proposed and not the baseline.
is appendix A of ASHRAE is only for proposed case?. in one of the project baseline case envelope is modeled based on appendix A, is it acceptable?
Usually just applies to the proposed. It could apply to an existing building envelope too so it might be used for a baseline situation.
Thanks for your reply. it really help me. can you please assist me regarding the one more issue. I am getting confused while modeling CW/HHW/Condenser water pump. The problem arises at the selection of GPM. For example., 19W/gpm...in this gpm is stand for actual gpm (which is proposed case). Suppose pump flow rate in proposed case is 100GPM, then in baseline case it would be 1900W (19w/GPM). Am i right?. Is it means flow rate should be same in both the cases?
Nope typically the flow is auto-sized in the baseline based on your temperatures. The power is typically an entered value calculated from the auto-sized flow. The 19W/gpm in G220.127.116.11 is required for the baseline. The proposed case should always be modeled as designed.
I have a small facility (20k sqft or so) that is approximately 45% office and 55% "transitional" residential.
I've modeled it as a residential with PTAC w/ HW Coil per zone, but I'm running into a couple of issues.
1. I'm not sure if modeling the zones as residential in the offices is truly appropriate. Should this be partially PSZ w/ furnace in the office zones?
2. The residential zones are so incredibly small, I'm getting a 2 kBtu load cooling load for each zone. PTACs can't be bought that small and the oversizing load is killing me in the proposed design.
Does Exception a under G3.1.1 apply?
I don't believe so.
The facility is under 20k sqft itself. So that eliminates exception (a).
The facility would either use System 1 or 3. So that eliminates exception (b) and (c).
The facility has no laboratory so that would eliminate exception (d).
So it sounds like you are required to model the whole building with a system 1.
Do you have PTACs in the proposed design too?
You can lump like zones together in the baseline.
I've lumped zones to stream line the simulation, but I don't think that has any benefit. I'm using multipliers to segment out the "like" zones.
I have PTACs in the proposed design with electric resistance heat. However we have an OSA unit that is gas-fired heat.
I'm getting killed on the heating because no one uses HW coils in PTACs. And I'm getting killed in cooling because my baseline PTACs are 2 kBtu units that are essentially nonexistent. We have 7 kBTU PTACs in the proposed.
Otherwise the units have high efficiency, 12 EER. The office area has 14 SEER split heat pumps.
I'm just not sure how to make this work.
I guess I do not understand the problems regarding HW coils and small PTACs in the baseline. Whether anyone uses a HW coil in PTACs or if they don't make small PTACs should not matter since you don't have to design it, just model it.
Sounds like this might be a "how to model it" question which tends to be software specific. Perhaps you should consider posting a question on the appropriate software listserv or contacting the software help.
When I compare the proposed 7 kBTU PTAC to a baseline 2 kBTU PTAC my energy consumption for cooling ine proposed supersedes the baseline significantly. And in reality I can't get a smaller PTAC to make the design meet the baseline.
Further because I have natural gas heat in the OSA unit I'm forced to use HW Coil baseline, but I can't get a PTAC with natural gas heat for design. I have to use electric heat, which again is killing me on my savings.
I have the model complete. It's pretty straight forward. I'm just trying to figure out how to make the Appendix G rules work and not get killed on the energy consumption.
Sorry I can't be of more help but detailed modeling issues are tough to try and address in a forum like this. I don't even understand why your baseline PTACs are so much smaller than the ones in your design. Like I said this sounds like a modeling issue. If you have a specific Appendix G question I can try to help.
If you are using electric resistance heat in the design I can understand why you are getting hammered compared to gas if the rates for gas are low and electric relatively high. Not sure what you can do about that.
I have one dubte about TABLE 5.5 of Standard 90.1.
For a renovation building without exterior wall modification applying for LEED NC 2009, it need to comply 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. of the exterior wall for the proposed building with table 5.5.
I use the Performance Rating Method through energy simulation.
Table 5.5 data is all prescriptive, not mandatory.
For building renovations see Table G3.1-5 Baseline (f) for modeling an existing building envelope.
Thanks Marcus, but in 5.4.1 say: "When insulation is required in Section 5.5..."
It is my dubte, if i have to comply 5.5 because mandatory provision 5.4.1 link to 5.5.
I know how to create to the model for baseline building, my dubte is for proposed building.
Thanks and sorry by my English
No worries I understand your confusion as I have addressed this question many times before. Please read the whole sentence and do not take a portion of it out of context.
5.4.1 references 18.104.22.168 to 22.214.171.124 which deals with the characteristics of the insulation materials, not the amount of insulation required. So this says where you have insulation being installed it must comply with certain characteristics. This does not link 5.4 to 5.5 and make 5.5 mandatory. So the insulation values are available for trade off.
I've been struggling with this issue for quite some time so any additional insight would be most appreciated. Here's my thought process based on a very literal interpretation. Section 126.96.36.199 states the following: "insulation shall extend over the full component area to the required R-value of insulation ...." And compliance with 188.8.131.52 is a stated requirement of 5.4.1. Therefore, it seems to me that Table 5.5 is linked to 5.4 making compliance with Table 5.5 mandatory.
Hello Stephen, your commentary is that i thought, but Marcus is right to explain that Table 5.5 is an alternative to the energy simulation. If you're using the energy simulation, the results of it penalize the isolation facility.
5.4.1 mark where isolation is required, it must be continuous, does not require installing insulation.
Your 184.108.40.206 excerpt is a characteristic of the insulation. The required R-value, the amount of insulation, is in the 5.5 tables. I can guarantee you that the 5.5 tables are not mandatory.
This is probably a simple question, but I can't find an answer to it in any LEED or ASHRAE resources. How do you determine if you fall under the "New Buidlings" or "Existing Building Renovations" cost savings percentage for this credit?
We have calculated a 24.6% cost savings improvement in the proposed buidling performance compared to the baseline buidling performance. The project is about 75% new and 25% existing renovation. There is no separation of the systems, so my guess would be we have to fall under the "New Building" column. If this is true, what is the cut off percentage to determine if you are in the new or existing column?
The threshold percentages are adjusted on an area weighted average basis. Picking some random numbers - if 10% is the new threshold and 6% is the existing threshold, then a 75% new and 25% existing adjusted threshold would be 9%.
If I follow correctly, under the NCv2.2 (LEED for Schools 2007) Rating System, with a 24.6% cost savings improvement new (75%) would get us 5 points and existing (25%) would get us 7 points. Therefore:
0.75 (5 points) + 0.25 (7 points) = 5.5 points
I'm assuming we can't round up, so we would go for 5 points for the credit.
Thanks for clarifying.
It might come out to about the same value but the weighted average is applied to the percent savings thresholds, not the points themselves. No half points and rounding. The entire table of thresholds and points is adjusted based on the ratio of new to existing.
Let's try another example in LEED for Schools 2007 14% new and 7% existing are both worth two points. Your project would have to get to 12.25% to earn 2 points (14-7)x(0.75)+7. Each subsequent point then uses the same 3.5% increment starting at 12.25%. So your 24.6% is worth 5 points.
We are working on a project with two high rise residential buildings, they do not share any common level except on the underground parking levels. Buildings are right next to each other.
I am confused on what HVAC system type / s are to be used in the non-residential areas for the baseline model.
In each building, levels 1st to 4th floors have some commercial areas (22,308 sf in total). From 90.1G3.1.1, it says I need to use additional HVAC system (System-6) in these areas.
1. Is my interpretation correct?
2. If it is,should I have system-6 in each level of each building?
3. If system-6 for non-residential and System-2 for residential areas will be used, then there should be no pumping energy?
1 - It would be typical to use a different system in the commercial areas. Which exception are you applying from G3.1.1?
2 - Not sure why there would be a system 6 on each level?
3 - Sounds right.
1. G3,1,1a, unlike 90.1-2007 G3.1.1 it doesn't say that "For systems 5, 6, 7, and 8, each floor shall be modeled with a separate HVAC system." but I am thinking to do the same.
2. I picked System 6 since it doesn't have heating under the category "4 or 5 floors or less than 75,000 ft² or 5 floors or less and
75,000–150,000 ft²" from Table G3.1.1A.
Is this approach acceptable?
OK the predominant condition is residential so a system 2 for residential is used assuming you have no gas heat.
For the commercial space, again assuming no gas heat, it seems like you should be modeling a system 4. Applying Option a - go into Table G3.1.1A using the square footage of the commercial space; so under 75k. Sounds like Option b also applies which leads you to the same system 4.
I just thaught that when it's more than 3 floors it' will be System 6, where I got confused..
Thanks a lot Marcus.
Technically if you apply G3.1.1 Exception a it would be a system 6 due to the number of floors, I stand corrected. Sorry for the confusion. If you apply G3.1.1 Exception b then it is a system 4. Since these exceptions are applied optionally it is your choice I suppose.
Nice to know that I have more than one option.
Thanks a lot!
Hi, Everyone, I try to search many places but didn't find "EAp2 Section 1.4 table.xls". It was said the file is under "credit resources", is this a wrong key word?or the file's name is wrong?
thank you very much for any suggestion.
Joey, the NC V2.2 Section 1.4 tables is in the EAc1 template (not EAp1) which can be previewed at http://www.usgbc.org/DisplayPage.aspx?CMSPageID=2464
under 'LEED Letter Templates'. Does that help?
The Green Engineer, LLP
Limits on interior and exterior light use can help in reducing energy loads.
EAc1 relies directly on the EAp2 documentation, and the strategies to earn the prerequisite are often similar to earning points under the credit.
Onsite renewable energy contributes to prerequisite achievement if pursuing energy modeling under Option 1.
Commissioning of energy-efficient building systems helps realize he operational benefits of the design.
The computer model developed for EAp2 – Option 1 is used in the M&V plan.
Daylighting reduces demand on installation and use of lighting fixtures resulting in energy use. To full realize the energy benefits, contorl electrical lighting with daylight sensors.
LEEDuser is produced by BuildingGreen, Inc., with YR&G authoring most of the original content. LEEDuser enjoys ongoing collaboration with USGBC. Read more about our team
Copyright 2013 – BuildingGreen, Inc.