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Beyond code compliance, but doable
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: Energy modeling
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:
- It can be used to provide feedback on your design both early on, and as the design progresses, so it’s best to use in this way rather than simply demonstrating compliance.
- It can help your team focus on the most cost-effective efficiency strategies, by plugging in different options and seeing the results.
- If your building is unconventional or complex in design, an energy model is the best way to account for that.
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.Option 2: ASHRAE Advanced Energy Design Guides
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.
Option 3: Advanced Buildings Core Performance Guide
The Core Performance Guide path is a good option if all of the following are true:
- your project is smaller than 100,000 ft2,
- you cannot pursue Option 2 because there is not an ASHRAE guide for the building type,
- your project is not a healthcare facility, lab, or warehouse,
- and you would rather not commit to the energy modeling required for Option 1.
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.
Reduce energy loads first
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.
District energy systems
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.
Look for incentives
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.)
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FAQs for EAp2
Is it acceptable to model a split-type AC with inverter technology compressor as a heat pump, like modeling VRF?
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.
A portion of our building envelope is historic. Can we exclude it from our model?
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.
For an existing building, do I need to rotate the model?
No, not for an existing building.
Our project has a large process load—75%. Despite our efforts to make an efficient HVAC design, the cost savings are minimal. What can we do to earn this prerequisite and be eligible for LEED certification? Is there any flexibility in how we model the process load?
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.
Our process load is higher than 25%. Do we have to justify that?
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.
Do the required savings for this prerequisite (and credit) need to come only from building energy, or also process loads?
The energy savings are based on the whole building energy use—building and process. LEED does not stipulate exactly where they come from.
Our local code references ASHRAE 90.1-2010. Should I use that for my documentation, or 90.1-2007?
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.
Our project doesn't have enough energy savings to earn the prerequisite. Can we get there by incorporating onsite renewables?
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.
Can I claim exterior lighting savings for canopy lighting even though a baseline model cannot include shading elements?
You can assume exterior lighting savings for canopies against the baseline, but not the shading effects of canopies.
The project is built on a site with existing exterior lighting installed. How should this be accounted for?
If exterior lighting is present on the project site, consider it as a constant in both energy model cases.
Can mezzanines open to floors below be excluded from the energy model?
Any conditioned area must be included in the energy model.
How do I provide a zip code for an international location?
The Energy Star portion of the form does not apply to international projects.
For a project outside the U.S., how do I determine the climate zone?
Use the tables and definitions provided in 90.1 Appendix B to determine an equivalent ASHRAE climate zone.
For a project outside the U.S., how do I determine the Target Finder score?
International projects are not required to enter a Target Finder score. Target Finder is based on U.S. energy use data.
Do hotel rooms need automatic light shut-off control?
For Section 9.4.1.1c, a manual control device would be sufficient to comply with mandatory provisions.
How commonly are the 90.1 mandatory compliance forms submitted as part of EAp2/EAc1?
Submitting these forms is not common; however, it can be beneficial if you are applying for any exceptions.
The Section 9 space-by-space method does not include residential space types. What should I use?
Use the building area method.
Can the Passive House Planning Package (PHPP) be used to energy model for LEED?
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.
Can the Trace 700 'LEED Energy Performance Summary Report' by uploaded to LEED Online in lieu of the Section 1.4 tables spreadsheet?
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.
Which baseline HVAC system do I use if my building has no heating or air conditioning?
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.
Our project has a diesel backup generator. Should we include it in our energy model?
If it is only used for backup and not for regular use such as peak shaving—no.
Can SHGC be higher in the proposed than in the baseline model?
SHGC is not a mandatory provision so it is available for trade-off and can be higher than the baseline.
Do I need to justify the electrical and fuel rates I am using in my model?
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.
Legend
- Best Practices
- Gotcha
- Action Steps
- Cost Tip
Pre-Design
Expand All
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. 
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.
USGBC
Excerpted from LEED 2009 for New Construction and Major Renovations
EA Prerequisite 2: Minimum energy performance
Required
Intent
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.
Requirements
Option 1. Whole building energy simulation
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:
- Comply with the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) in Standard 90.1-2007 (with errata but without addenda1) or USGBC approved equivalent.
- Inclusion of all the energy costs within and associated with the building project.
- Compare against a baseline building that complies with Appendix G of Standard 90.1-2007 (with errata but without addenda1) or USGBC approved equivalent. The default process energy cost is 25% of the total energy cost for the baseline building. If the building’s process energy cost is less than 25% of the baseline building energy cost, the LEED submittal must include documentation substantiating that process energy inputs are appropriate.
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.
OR
Option 2. Prescriptive compliance path: ASHRAE Advanced Energy Design Guide
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.
Path 1. ASHRAE Advanced Energy Design Guide for Small Office Buildings 2004
The building must meet the following requirements:
- Less than 20,000 square feet (1,800 square meters).
- Office occupancy.
Path 2. ASHRAE Advanced Energy Design Guide for Small Retail Buildings 2006
The building must meet the following requirements:
- Less than 20,000 square feet (1,800 square meters).
- Retail occupancy.
Path 3. ASHRAE Advanced Energy Design Guide for Small Warehouses and Self Storage Buildings 2008
The building must meet the following requirements:
- Less than 50,000 square feet (4,600 square meters).
- Warehouse or self-storage occupancy.
OR
Option 3. Prescriptive compliance path: Advanced Buildings™ Core Performance™ Guide
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:
- Less than 100,000 square feet (9,300 square meters).
- Comply with Section 1: Design Process Strategies, and Section 2: Core Performance Requirements.
- Health care, warehouse and laboratory projects are ineligible for this path.
Projects outside the U.S. may use ASHRAE/ASHRAE/IESNA Standard 90.1-2007 Appendices B and D to determine the appropriate climate zone.
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 located at www.usgbc.org/leedisglobal
Potential Technologies & Strategies
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.FOOTNOTES
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
Organizations
Database of State Incentives for Renewables and Efficiency (DSIRE)
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.
New York State Energy Research and Development Authority (NYSERDA)
Useful web resource with information on local/regional incentives for energy-efficiency programs.
American Council for an Energy-Efficient Economy
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.
New Buildings Institute
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.
U.S. Department of Energy, Building Energy Codes Program
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.
Rensselaer Polytechnic Institute: Daylighting Resources
Research center at RPI provides access to a wide range of daylighting resources, case studies, design tools, reports, publications and more.
IBPSA
International association of energy modelers with various national and local chapters.
Architecture 2030
Non-profit organization aiming at design community to increase collaboration for designing energy efficient buildings.
Low Impact Hydropower Institute
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.
U.S. Department of Energy Building Technologies Program
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.
Web Tools
Energy Analysis Tools
This website discusses the step-by-step process for energy modeling.
Advanced Buildings Technologies and Practices
This online resource, supported by Natural Resources Canada, presents energy-efficient technologies, strategies for commercial buildings, and pertinent case studies.
U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy
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.
U.S. EPA, Combined Heat and Power Partnership
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.
Advanced Energy Design Guides
Free download of AHSRAE energy savings guide, use for Option 2.
Lawrence Berkeley Lab: Building Technologies Department
Research warehouse for strategies and case studies of energy efficiency in buildings.
Efficient Windows Collaborative
An online window selection tool with performance characteristics.
Whole Building Design Guide (WBDG)
This website lays out design process for developing an energy efficient building.
AIA Sustainability 2030 Toolkit
This website discusses ways to improve design for lower energy demand as they relate to the AIA 2030 challenge.
Windows for High-Performance Commercial Buildings
This website includes discussion of design issues, materials and assemblies, window design decisions and case studies.
California Integrated Waste Management Board: Environmental and Economic Assessment Tools
This site lists multiple web-based and downloadable tools that can be used for energy analyses.
DEER: Database for Energy Efficient Resource
This database is maintainted by the California Energy Commission and lists resources related to energy use and efficiency.
Energy Design Resources - CA
Energy design tools are available to be used for free online or available to download.
Building Materials Property Table
This website lists performance characteristics for various envelope materials.
One Building
This is an online forum of discussion for energy efficiency, computer model software users.
EPA’s Target Finder
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.
Building Energy Software Tools Directory
This directory provides information on 406 building software tools for evaluating energy efficiency, renewable energy, and sustainability in buildings.
EnergyPlus Format Weather Data Resources
Weather data for more than 2100 locations are available in EnergyPlus weather format.
DOE-2 Format Weather Data Resources
Weather data for U.S. and Non-U.S. locations in BIN format.
BEMbook – Building Energy Modeling Book
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.
Technical Guides
Advanced Buildings Core Performance Guide
A guide for achieving energy efficiency in new commercial buildings, referenced in the LEED energy credits.
ENERGY STAR Building Upgrade Manual
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.
Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 – Design & Construction
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.
COMNET Commercial Buildings Energy Modeling Guidelines and Procedures
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.
2009 ASHRAE Handbook of Fundamentals, Chapter 19
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).
Treatment of Distric or Campus Thermal Energy in LEED v2 and LEED 2009 (Updated August 13, 2010)
Required reference document for DES systems in LEED energy credits.
Publications
ANSI/ASHRAE/IESNA Standard 90.1–2007 User’s Manual (ASHRAE).
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 Information Administration
Energy statistics from the U.S. government.
New Buildings Institute— Advanced Lighting Guidelines: 2003 Edition
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.
Building Energy Performance News
This website offers information on energy efficiency in buildings, highlighting success stories, breakthrough technology, and policy updates.
GreenSource magazine
Bimonthly publication on case studies and new technologies for energy efficiency in commercial buildings.
AIA Local Leaders in Sustainability: Green Incentives
AIA publication highlighting local and state green building incentives.
Federal Research and Devlopment Agenda for Net-Zero Energy, High-Performance Green Buildings
2008 guidelines and performance goals from the National Science and Technology Council.
Energy Design Resources (EDR) Simulation Guidebooks
Information about energy-efficient building practices available in EDR's Design Briefs, Design Guidelines, Case Studies, and Technology Overviews.
Software Tools
Building Energy Software Tools Directory
DOE tools for whole building analyses, including energy simulation, load calculation, renewable energy, retrofit analysis and green buildings tools.
Building and Fire Research Laboratory
This is a computer program that predicts the one-dimensional transfer of heat and moisture.
DesignBuilder and EnergyPlus
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.
Integrated Environmental Solutions – Virtual Environment Pro / Apache
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.
Advanced Energy Design Guide Checklist
Option 2: Prescriptive Compliance Path
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.
Advanced Buildings Core Performance Guide (CPG) Checklist
Option 3
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.
Energy Simulation Narrative
Option 1
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.
Equipment and Product Cut Sheets
All Options
In your supporting documentation, include spec sheets of equipment described in the Option 1 energy model or Options 2–3 prescriptive paths.
PRM Table
Option 1
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.
Samples
Tariff Charges
Option 1
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.
Samples
Modeled Energy Reductions
Option 1
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.)
U.S. Climate Zones
All Options
The climate zones shown on this Department of Energy map are relevant to all options for this credit.
Tools
Appendix G Fan Power Calculator
Option 1
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.
LEED Online Forms: NC-2009 EA
The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 EA credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.
Version 4 forms (newest):
- EAp1: Fundamental Commissioning
- EAp2: Minimum Energy Peformance
- EAp3: Fundamental Refrigerant Management
- EAc2: On-Site Renewable Energy
- EAc4: Enhanced Refrigerant Management
- EAc5: Measurement & Verification
Version 3 forms:
- EAp1: Fundamental Commissioning
- EAp2: Minimum Energy Peformance
- EAp3: Fundamental Refrigerant Management
- EAc1: Optimize Energy Performance
- EAc2: On-Site Renewable Energy
- EAc3: Enhanced Commissioning
- EAc4: Enhanced Refrigerant Management
- EAc5: Measurement & Verification
- EAc6: Green Power
These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictsions for these forms; for more information, visit LEED Online and click "Sample Forms Download."
Design Submittal
Documentation for this credit can be part of a Design Phase submittal.
LEEDuser is produced by BuildingGreen, Inc., with YR&G authoring most of the original content. LEEDuser enjoys ongoing collaboration with USGBC.
1381 Comments
Boilers minimum efficiency ASHRAE 90.1
Can anynone clarify if boilers minimum efficiency requirements set in table 6.8.1 F is based on fuel higher heating value (HHV) or lower heating value (LHV)?
The answer may be in the referenced testing standard 10 CFR Part 430 - http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=583697b320372e9df538012c...
http://www.ahrinet.org/App_Content/ahri/files/standards%20pdfs/BTS-2000.pdf
Is then referenced as the proceedure...see page 34 i think.
Exemptions to ASHRAE 90.1 - 2010
Hello all,
We're working on a project that has an area that is includeded under exemptions to ASHRAE 90.1-2010 Interior Lighting Requirements. I'm wondering if anyone out there has seen a case where these exemptions have not been followed by LEED? I.E. excluded by ASHRAE in modeling but made to be included by LEED / GBCI reviewers?
Even if it is an exemption you still must model it identically in the baseline and proposed. It basically becomes just another process or unregulated load. This is an Appendix G requirement (see Table G3.1.1-1) and LEED requirement that everything that impacts energy use must be modeled, no exceptions.
Outdoor Air Intake: Baseline vs. Proposed
We are currently working on a LEED project whose Baseline Building will have an HVAC system 5 installed. Taking into account that section G3.1.1 of ASHRAE 91.1-2007 states that “for systems 5, 6, 7, and 8, each floor shall be modeled with separate HVAC system” we have modeled the system accordingly.
For each floor we have divisions with different ratios of outdoor air intake and to respect those ratios we need to set the system to operate for the critical division. Taking into account that there are divisions with 100% of outdoor air in almost every floor, then almost every systems are being modeled for 100% of outdoor air, which is causing a great increase in the heat consumption.
The problem is that by doing the aforementioned, the outdoor air intake of the Baseline will not be the same as the Proposed, but, if we do not proceed like above mentioned (i.e., if we set the system for the minimum outdoor air intake) we’ll not be ensuring that every division has the outdoor air intake that it’s supposed to have.
In your opinion what should we do to solve this problem?
Thank you.
The OA must be identical in total in both models (unless there is DCV in the Proposed and not the Baseline). Hard to tell how you fix the problem without knowing more about how you are modeling it. You should be entering the amount of OA and not having the software calculate it. Also keep in mind that the Baseline systems do not actually have to function from a design perspective, just from an energy perspective.
EQUIPMENT CAPACITY OVERSIZING
I AM BEGINEER IN THIS FIELD. I HAVE A LITTLE DOUBT ABOUT EQUIPMENT CAPACITY OVERSIZING.
I JUST WANT TO KNOW THAT, IN WHICH PART OF THE HVAC SYSTEM (IN BASELINE CASE) EQUIPMENT CAPACITY OVERSIZING DONE. IS IT 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.'S, 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.'S, UNIT HEATERS ETC???...ANY SUGGESTIONS....THANKS IN ADVANCE
Very good question. Ideally all the systems, but if I were a reviewer, I would only look at the fan(s), chiller and boiler sizing. Here the sizing has the greatest impact on efficiency. If your coil is oversized, it may only impact on the pumping power. Pumping power inturn is very roughly estimated as no pressure drop in the piping is required to be dynamically simulated in the simulation. For the baseline pumping power is a function of mass flow. Electrical equipment is also not that critical in my opinion. Most softwares are limited in what they can actually size, by internal model assumptions.
Anyone else?
thanks sir. your comment really help me. I little bit wondered when i listen from my colleague that, oversizing can be done at system level or zone level but not at both. according to me, system level is what we can say it a source which generate a medium for HVAC it may be include but not limited to boilers, chillers etc but i am not confirmed about zone level, it might include fans or else. So, according to you can we oversize these all parts by 25 and 15 %?? Any thoughts??????
+++++ can you please give me more info on zone level equipments oversizing?
Correct it can't be done at both the system and zone level. In general it is done at the zone or the plant level, usually the zone level. Again it can't be at both.
Baseline Lighting Power density
Hi, Can you help with the following two issues:
1.I understand proposed total installed lighitng power has to be the same in the energy model and in SSc8. Does the Baseline lighting power has to be the same too? As an energy modeller can I disagree with the lighting consultant on how areas for "space by space" method are set?
2.How stringent is the definition of "decorative power allowance". I get the feeling the lighting consultant is playing the standard by arbitrarily defining decorative lighting fixtures to what seems to be general lighting in order to get more power allowance. What is your experience in this issue, anyone had any reviews regarding this?
Thanks in advance!
Santiago.
1. The exterior lighting in the models needs to be consistent with SSc8. You can disagree but will need to use the same value as it will be checked by the reviewer for consistency.
2. Whether this issue would be raised in a review depends on what gets submitted. Often not enough information gets submitted to evaluate it in a LEED review. To demonstrate whether it is decorative or not I would suggest that if it is removed the remaining lighting will meet the lighting design requirements. If that is the case then it is decorative, if not then it is at least part general and would not qualify for the extra allowance.
Energy modeling - Adjacente building
Hi,
I have a doubt when modeling proposed and baseline building.
If I have some adjacent buildings to the proposed model, should I include their geometry in the proposed/baseline model, in order to account for the shading effect?
Thanks.
Luana
You are not required to model adjacent building in the 90.1-2007 version. In 90.1-2010 you are required to model them identically.
Just because you are not required to do so does not mean that it isn't a good idea. For the sake of accuracy we certainly would model adjacent buildings or landscape features that would influence the energy use of the building.
Very interesting...I was once told by my reviewers to cut out my surrounding buildings and (in that project) large trees which were in both models (a pitty for all the background research and modelling of that kind of tree species for shading effect).
At the end of the day it is a energy usage comparison, so shouldn't make so much difference, unless you didn't shade certain parts with external blinds because there happens to be a huge tree in the way.
Yep Jean compliance models, like the one required for LEED, are for comparing the building design to a uniform baseline so as long as they contain some of the same assumptions the relative difference is minor. Improving the accuracy of the modeling results is sometimes a related but not always consistent objective when doing a compliance model strictly according to the rules.
Brewery Process Load - Baseline and Proposed Case Set-up
The brewery I am modeling has large percentage of energy consumption associated with the process load. From past posts I understand I need to write a thorough narrative explaining the standard practive baseline and the stategy for energy savings of process load for the Proposed Case.
We have the energy data of MBTUs/barrel from World Breweries Energy Benchmarking and MBTU/barrel calculated from another very similar brewery of the same company in another location. My questions are:
1. Can I use this MBTUs/barrel comparison to demonstrate the savings of process load of the Proposed Case from the Baselin Case for this project (by applying a percentage of process load to the total consummption)?
2. I am using Trane Trace for energy modeling. The process load added in the energy model is typically just a number under "Base Utilities". I am thinking using a total number for both baseline and proposed case based on MBUTs/barrel and the barrel production of this new brewary. Is that enough?
3. There are many chillers associated with only the process load . Should I model it in my energy model? (e.g. selecting chiller types, assign capacity and efficiency, etc) or just take them as a part of the lump sum number of process load?
1 and 2 are not nearly enough in my opinion. While the approach you describe is minimally acceptable for traditional process loads in many building types it is not nearly adequate when the calculation of the savings comes into play. You need to explicitly model the specific process loads.
NOTICE - preaching to the choir zone ahead . . . (also not meant to pick on just you Xun Jia)
Non-regulated process loads are too often either assumed or ignored by too many projects. Even marginally good modeling practice would be to model these loads as accurately as possible and not by entering "just a number" in the model. This often requires asking the owner to tell you the nature of those loads beyond figuring out electrical capacity. If the owner does not know then help them to figure it out. Just because it is not regulated and you are not designing the system does not mean that you should ignore the energy saving potential of these end uses in the spirit of LEED.
Move your thinking beyond the minimum.
UnmetLoadHours - Do we have clarity yet?
The definition of Unmet Load Hours has been vague for quite some time. ASHRAE 90.1 2010 was supposed to address this issue. Do we have some resolution about this yet? For example:
1) Do we count the sum of all the unmetloadhours for all the zones, or just the zone with the most unmetloadhours (this was a problem for 200 zone models)?
2) What is the tolerance of the zone temperature to the zone setpoint before the timestep is counted as unmetloadhour time, and what is it based on.
3) Is there an allowance for "pull down time", i.e. the time that it takes for the zone to reach setpoint after recoving from the setpoint change after night setback. During this time the loads will be unmet.
Looks like 2010 dropped the 50 differential but kept the 300 overall limit. The 2010 language indicates projects can exceed the 300 limit by providing sufficient justification that the accuracy of the simulation is not compromised.
I do not see that 2010 specifically addressed the issues you raise. Here is my understanding - 1) coincident unmet load hours in multiple zones only count as one unmet load hour; 2) probably depends on the software; 3) whether it counts or not depends on how you model the transition period - for example, if you can model steps or optimal start it can reduce the unmet load hours.
Energy modeling - ASHRAE §G3.1.2.4
Hi all,
We are undertaking the energy modeling of an office building and the Baseline is using a System 7, climatic zone is 4a. The building is connected to a heating District Energy System.
Could someone please help me to understand ASHRAE 90.1 §G3.1.2.4? The section states, “Supply and return fans shall operate continuously whenever
spaces are occupied and shall be cycled to meet heating and cooling loads during unoccupied hours. If the supply fan is modeled as cycling and fan energy is included in the energy-efficiency rating of the equipment, fan energy shall not be modeled explicitly.”
In our case, the supply fan is modeled as the cycling fan. I cannot see how the supply fan should be modeled without taking into account its energy consumption. Should the extract fan be cycled too?
Thanks for your help.
The energy efficiency rating is not the same as the energy consumption. Some measures of efficiency (COP, EER, SEER) include the fan energy (see G3.1.2.1). The second sentence means that if the fans do cycle and the efficiency includes fan power you do not model extra fan power as it is already included. For example, a heating/cooling system that cycles with temperature that has a dedicated outside air system that runs continuously would not add more fan power than already included in the efficiency measurement for the heating/cooling system..
The extract fan would follow the same rules.
LPD - SI vs IP
My turn - a question for those of you who have the SI version of 90.1. Is the lighting power density identical in both versions? For example, stairs in Table 9.6.1 in the IP version are 0.6 W/sf. Is the SI version 6.45 W/m2? Or is it rounded to 6.0 W/m2?
It is rounded to zero decimal place in SI version.
We did not round it up, and used the same number in SI version. We did round it up in previous project, and were asked to changed by reviewer.
Just to be clear - so the SI version in Table 9.6.1 lists 6.0 W/m2 for stairs?
Thats correct marcus. They remove the decimal place entirely. It lists stairs at 6W/m2.
Energy Modeling for DMV Inspection Station
We have a project in question that is DMV office and vehicle inspection station. The vehicle inspection lanes side of the building are approximately 50% of the total project square footage. The inspection lanes have a series of drive through lanes with 14' doors that remain open throughout the 12 hour operating period each day. Each lane is designed to accommodate any potential vehicle including commercial trucks and buses which drives the door sizes. This creates a scenario in which the full length of both entry and exit doors are open during occupied operation hours hours. The floor will have radiant heat for freeze protection and pre-manufactured operator booths that are heated and ventilated. In addition there is a series of testing equipment to include larger equipment and motors to test brakes, etc. What is the proper approach to take in the modeling of the overall building to avoid an undue hardship being placed on the model due to the open inspection lanes?
The doors will be open in both models so no extra hardship in comparison.
Check out Systems 9 or 10 from Table G3.1.1A in 90.1-2010 which can be used for heating only spaces.
Does PPR piping need insulation?
We have run into a situation with piping material used in a hotwater distribution system. Our client is using Polypropelene piping. (PPR)
The thermal transmitance of this piping is in the range of .1-.22 W/m.k.
Do they need insulation for this piping? Thermal transmitance for copper and iron piping is 400 and 80 W/m.k.
Looks like it needs insulated unless one of the exceptions to 6.4.4.1.3 applies.
Rudolph, take a look at ASHRAE 90.1-2010, Table 6.8.3A, note 'e'. It addresses the topic of non-metallic pipe. As LEED 2009 allows you to use addenda to ASHRAE 90.1-2007, if you can find the addendum that added note 'e' and comply with that particular addendum in its entirety, you might be able to get by with using PP piping without insulation (or at least reduced insulation). Good luck!
Make sure since this is a mandatory provision.
In my experience even plastic pipe will have enough heat loss that pipe insulation makes sense.
Seek not the exception to enable lower levels of efficiency but seek to improve energy efficiency.
Updating the LEEDOnline form after being accepted
Dear All,
If the USGBC awards 4 points under EA Credit 1, but then the design team decides to add significant lighting to the project which will increase the Proposed consumption (and consequently award 3 points), does the team need to "Appeal" the credit for this change? I.e., pay some $800 for an already approved credit in order to decrease the number of points?!
Can't we just communicate with the GBCI through their website and ask to update this issue? What would you guys do?
Thanks!
No need for an appeal.
Did you do a split D/C submission or a combined submission? If split and EAc1 was awarded in the design phase you can resubmit in the construction phase noting that something changed during construction. If combined contact GBCI through their web site and request the update.
Thanks Marcus!
It's actually a split.
But if it were the other way around and we wanted to claim additional savings after they have awarded the credit (the Electrical engineer decided to lower the lighting to get more points), we will need to appeal, correct?
Thanks.
I think that if you wanted to add a point after the review was complete and the certification had been accepted you would have to pay for an appeal.
Oh so we would need to appeal only if the LEED Certification has been awarded?
But I'm thinking in terms of GBCI's perspective, if they spend time reviewing a big thermal model and award the points, then the design team, assumingly, shifts from DX-Split units to more efficient VRV units, the whole model will change (at least everything related to Heating & Cooling).
I don't think the GBCI would be happy to review again this big complicated model, for free!
Assuming you submitted EAp2 in the design phase and it was approved in the design final review, any changes that happened in construction that affect the results are supposed to be resubmitted in the construction review phase. This hold true for all of the design phase credits.
Yes the reviewer will not be happy about it but they are obligated to review it again in the construction review phase as part of the review process. This review should not be nearly as extensive as the first one since it will be limited to fewer issues. This resubmission only gets one additional review, not two, so make sure to get it right!
For this reason we almost always defer the energy model to the construction review phase so we do not have to do the final model twice.
Great, thanks Marcus!
I'm assuming this applies to any design credit submitted & awarded during Design Review.
Yep that is my assumption too.
ASHRAE 90.1-2007 6.4.1.4 - Verification of Equipment Efficiences
There is a Brazilian HVAC manufacturer that has an centrifugal chiller with magnetic bearings equipment (air condensation). The equipment is not tested by AHRI and there is no laboratory in Brazil that can do this test. As there is no laboratory in Brazil that can do this test, we would like to know if this equipment falls into the option “d” of 6.4.1.4 (“if no certification program exists for a covered product, the equipment efficiency ratings shall be supported by data furnished by the manufacturer”).
Or, the equipment needs to be tested outside Brazil? Does AHRI tests this kind of equipment?
That is correct fabiano. The dificulty is that magnetic bearing chillers rarely comply with the full load eficiency requirements of ASHRAE 90.1-2007. Since AHRI 550-590 doesnt take magnetic bearings into account in determining chiller efficiency, it would seem that chiller is exempt. I doubt however, that a reviewer would allow you to exempt something as big as a chiller from efficiency requirements. LEED allows use of ASHRAE 90.1-2010, which takes magnetic bearing chillers into account, so long as the the entire 2010 standard is applied to the project.
Hi Rudolph,
According to the manufacturer test, the equipment full load efficiency complies with the requirements of ASHRAE 90.1-2007. Considering there is data furnished by the manufecturer, showing the equipment efficiency compliance, and that no certification program exists for this product, couldn’t we consider the item 6.4.1.4 compliance by using option “d”?
Sounds like you could possibly use 6.4.1.4 to demonstrate compliance.
I would probably investigate both options to demonstrate compliance. If 90.1-2010 covers this equipment and the manufacturer has published test data relative to the requirements then the baseline efficiency will be clear and straight forward. If not then using 6.4.1.4 may be possible but you will need to provide more explanation about how the equipment meets the efficiency requirements.
One correction to Rudolph's statement above - projects can use addenda to 90.1-2007 (the whole addendum must be applied) without having to apply 90.1-2010 in its entirety.
The table 6.8.1C does not specify the type of bearings, so I thought that this type of equipment should comply with the minimum efficiency of Air cooled, with condenser, electrically operated.
Do you agree with that? Or should I consider that the equipment falls to the section 6.4.1.4 item “d”?
LED Screens--In or out of the Baseline
I'm working on the a project that has LED "media screens" on each of its four facades. Would I include this energy and power load in the baseline as part of "process"--it's for advertising and entertainment, so it takes advantage of the ASHRAE exemption for such--or would it only be included in the design case because it's unique to this project ? In this latter case, I'm assuming that the energy consumption would need to be compensated for by other ECMs in the building in order to qualify for LEED.
It would be considered process and be modeled identically in both cases. Basically it sounds like a really big monitor so it would be treated the same as a small one.
Thanks, Marcus. Sounds so simple when you put it that way.
Option 1 for District Thermal Energy
I’m modeling a building that is connected to a district CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. system that produces heat and electricity.
No cooling system, neither in the building nor in the CHP system, is available. There is no back-up energy.
I’m using the document “Treatment of District or Campus Thermal Energy in LEED” and since detailed data concerning the CHP system are not available I’m using Option 1 (streamlined path).
The building is nonresidential and its surface is less than 2300m^2. For the baseline model shall I use system 3 or system 4 of table G3.1.1A? Because of Table 2 and Table 3 of “Treatment of District or Campus Thermal Energy in LEED”, I guess that I have to model "PSZ-AC w/distrct heating". Am I right?
What efficiencies shall I use (par. 2.4.1.2.3 and Appendix D regard Option 2 while I’m using Option 1)? I guess that I have to consider the purchased heat, not the primary energy, both for the model of the proposed building and for the baseline model, therefore efficiencies shall not be considered for heating. Am I right?
Regards
Assuming the ultimate heat source is fossil fuel (burned by the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source.) I would use system 3. Under Option 1 you are correct. Correct again on heating efficiency as the heat is just treated as purchased heat.
Thank you, Marcus.
In the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. system the energy source is woodchip, but I think that if one uses Option 1 it doesn't matter what fuel is burned, because considering renewable energy used in the district CHP system in order to get points is possible only if Option 2 is used. Right?
Yes you are correct.
SF used for energy model vs. building GSF
Our building energy model s.f.(table eap2-1) 74,000+/- does not match the gross building s.f. reported in 1.1A 94,000+/-. The difference is approximately 20,000 s.f. and is due to wall thickness and chases in a 4 level builidng. The LEED reviewer is stating that the two s.f. numbers must match - is there guidance in the LEED credit or ASHRAE 90.1 that indicates how this s.f. must be treated?
A gross to net difference of over 20% is extremely high. Normal range is under 10%. The energy model should be modeling gross sf overall and net for things like lighting.
If your project does indeed have such a difference I would suggest you provide a detailed narrative explaining it, show your calculations and perhaps even provide drawings to back up your claim.
EAp2 Prescriptive Path- Renovation and Addition
EAp2- Option 2 Prescriptive Method
The current project consists of an existing building that is being renovated along with a new addition to the building. The prescriptive method indicates that 1/2" of rigid insulation is required. Is this required for the existing building? What are the requirements to update the existing building envelope to the current ASHRAE standards? The new addition will be compliant to all ASHRAE prescriptive requirements. The addition is 40% of the entire project.
This prescriptive approach is all or nothing. If you were just renovating a building that renovation would need to comply with every strategy. The ASHRAE AEDG contains prescriptive requirements above the 90.1 prescriptive levels. So you would need to implement every item on the prescriptive list in the AEDG in order to use this option.
Office Building + warehouse + Production Floor
Hi all,
We have a project back in 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. 1 and in the struggling to understand energy modeling for such building combination.
Our office are using unitary split units with OA injection fan, while the production floor and warehouse are naturally ventilated.
Do we just simulate the office building only or has to include the production floor + warehouse.
Any feedback is greatly appreciated.
If the entire building is part of the LEED project submission then it all needs to be modeled.
You can use System 9 or 10 from Table G3.1.1A in 90.1-2010 for the unconditioned spaces.
Hi marcus,
in 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. 1, we need more cooling and rather not on heating. But the suggested system 9 or 10 (correct me if i'm wrong) were meant for heating for storage. while the actual, our warehouse and production floor are purely natural ventilated or unconditional spaces.
please assist.
System 9 and 10 would also cover ventilated only spaces. In 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. 1 the heating would likely not come on and therefore not affect the modeling results.
G3.1.2.9 and Miscellaneous Exhaust Fan Power
Section G3.1.2.9 says that baseline "system fan electrical power for supply, return, exhaust, and relief (excluding power to fan-powered VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. boxes) shall be calculated" using the formulas given. This statement has origins in section 6.5.3.1.1 which requires that fan power not exceed a calculated amount including "supply fans, return/relief fans, exhaust fans, and fan-powered terminal units associated with systems providing heating or cooling capability."
The question I have (and please point me to any existing precedent on this) is how exactly do we define which fans are "associated" with systems providing heating and cooling? Should section G3.1.2.9 be interpreted as:
a) System-wide Area Interpretation - Only the main supply, return, relief, and/or exhaust fans which serve the entire area served by the supply system are to be included. This would mean toilet exhaust fans or other fans serving only part of the area (maybe one or two rooms) are considered miscellaneous and remain the equal in proposed and baseline cases. Transfer fans would also be equal in the proposed and baseline cases even though they provide indirect cooling effect since they do not serve the entire area of the system (example is an electrical closet with fan that trades are with an open plenum).
b) Tied Fan Systems Interpretation - Only fans that must run when the HVAC system is running are included in these calculations (examples are laboratory exaust fans tied to the supply unit, toilet exhaust fans tied to the HVAC unit serving the adjacent area, other fans that are tied to the supply system to operate simultaneously). This would mean any exhaust fans on a switch (switched toilet exhaust fans, switched kitchen grease exhaust fans not tied to a makeup air unit, other fans that operate independently of the main HVAC system) or switched transfer fans for indirect cooling would not be included in the calculations and would remain equal between proposed and baseline cases.
c) Fans Provided Only for Cooling Effect - All fans that are provided for cooling effect (either direct or indirect) must be included in the calculations. Toilet exhaust fans, fume exhaust fans, kitchen grease exhaust fans, etc. would not be included in the calculations and would be modeled equally in the proposed and baseline cases since they are provided for ventilation rather than solely for cooling effect. Transfer fans provided for indirect cooling would be included in the calculations since they do provide cooling. These fans may not be directly associated with any particular HVAC system (penthouse fans with no cooling system, etc.), so the question would remain as to whether they must be included in the fan power calculations of other systems in the building or if they are to be modeled equally in the proposed and baseline cases since.
d) All Fans in the Building – All fans in the building, regardless of function, are included in the calculations since the fact that they move air means they potentially provide cooling effect. This would mean any fan (switched, tied to BMS, ventilation only, etc.) would be included in the calculations and no exceptions would be allowed for any fans to be treated as miscellaneous exhaust modeled equally in the proposed and baseline cases. This option is difficult because baseline systems do not necessarily serve the same areas as proposed systems and it may not be clear which baseline system the fan power should be associated with.
There may also be additional options not presented that better define how the section should be interpreted.
Any help would be great since it appears review of this matter is inconsistent.
Matt, I agree that this is a confusing subject. I usually treat exhaust fans as identical between the baseline and the proposed. But looking into this again, the contents of Section 6.5.3 of 90.1-2007 and the definition of "fan system" in the 90.1-2007 User's manual seem to make it clear that exhaust fans are included in the fan power allowance if they are greater than 1 HP and if they exhaust conditioned air. The Advanced Energy Modeling for LEED guidance also states that the total fan power for the baseline system design reflects the sum of "power modeled for supply, exhaust, return, and relief fans." I would be interested to hear more about the specific review comments you or others have received on the subject.
We agree with option b). We would typically include exhaust fans as part of the system if they are controlled centrally. If they are on a separate control like a wall switch then they are independent and should be modeled identically above the G3.1.2.9 calculations. Whether the exhaust fans serve all or only a portion of the area is irrelevant.
Thanks to all for weighing in on this. I tend to also agree with Option B since it encompasses fans that need to run in order for a complete HVAC system to function. Toilet exhaust fans often fall into this category in commercial buildings.
As a side note, I did also find in the ASHRAE 90.1-2007 User's Manual that "all fans that operate at peak design conditions" are to be included in the calculations, but that doesn't really address switched fans that are technically designed to be on but don't respond at all to outside temperature "design conditions". It makes sense to me that fans provided for alternate purposes (as evidenced by switched control or other independent control) are miscellaneous exhaust and should be modeled equally in the proposed and baseline cases.
Industrial machines are considered process energy?
We are working to certify and industrial plant and we are not sure whether the energy consumption from the machinery used for product manufacturing should be included in the energy modeling. ASHRAE 90.1 Section 2.3 states that "The provisions of this standard do not apply to:
a…
b…
c. equipment and portions of building systems that use energy primarily to provide for industrial, manufacturing, or commercial process"
Does the statement above apply for LEED projects? Is industrial load from the machinery considered a type of process energy for LEED? My understanding is that LEED certifies buildings, not processes, therefore this type of process energy should not be included in the calculations. But would like to hear your opinions and interpretations on this issue.
Thanks
ASHRAE 90.1 does not apply to the energy loads you've noted however they will need to be included in the energy model per the language of the reference guide.
Thanks David.
I'd still like to elaborate a bit more on that, I'm afraid I'm not asking the question correctly. The RG says on p. 237: "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)."
It never mentions industrial load, such as machinery and, by analogy, we can infer that load from production equipment doesn't compare with the types of load mentionded in the RG. Even though load from the machinery could pontentially be included under "Other", that would be a nonsense, since in industries, over 90% of the energy consumption is from the machines used for product manufacturing (this is the case of our project, the plant produced automobile pieces). Such situation, would make it unfeasible for most industrial plants to pursue LEED certification, because of the 10% reduction required in EAp2. Unless, of course, the client decides to interfere in his production process, which is not what LEED is aimed for in my understanding, since LEED is for bulding, not processes...
In this case the purpose of LEED is to save energy. It does not matter if it is process or non-process energy use.
David is right the requirements for this prerequisite and credit are clear - all energy use within and associated with the project must be included. So for an industrial facility to produce sufficient savings the process loads need to be addressed. There are many industrial facilities that have demonstrated energy savings related to their process and earned LEED certification.
Think beyond the building.
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