CI-2009 EAc1.3: Optimize Energy Performance—HVAC

  • CI_EAc1-3_Type1_HVAC Diagram

  • What’s in your scope

    This credit requires that you demonstrate energy savings from HVAC systems and components within your project scope—only systems installed as part of the LEED-CI project, or systems within the LEED boundary. (See more detail on scope below.)

    Two options, for up to ten points

    There are two options for achieving this credit, either of which could earn five or ten points for your project. 

    • Option 1 uses a prescriptive approach. You earn five points for calculating building loads and meeting mechanical system efficiency requirements in accordance with the Advanced Buildings: Core Performance Guide (CPG), Sections 1.4, 2.9, and 3.10. You can also, separately or in addition, earn five points by demonstrating appropriate zoning and controls to promote energy efficiency. 
    • Option 2 is a performance approach for projects that use energy modeling to predict how much energy they’ll save. Your project has to show 15% savings (compared to the minimum performance guidelines of ASHRAE 90.1-2007) to earn five points, or a 30% savings for an additional five points. These are challenging thresholds, because you can only count savings from HVAC systems and equipment and you have to reach one of these thresholds to earn any of the points—prorating is not an option. An Exemplary PerformanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. point via IDc1 is also available if you can demonstrate 33% energy savings. 

    Which way to go?

    If your HVAC equipment is fairly conventional, it will likely be listed in the CPG, making Option 1 the easiest approach for five points. More unique or innovative systems may find it better to go with energy modeling.

    Is your project located in a LEED-certified building? If so, investigate if the building already has an energy model that you could adapt for this credit, potentially saving cost and enabling you to earn a better score. If not, consider whether your project scope is large or complex enough to warrant using an energy model.

    Watch out for hidden requirements

    To achieve the first five points in Option 1 the design engineer has to demonstrate that the HVAC system in the space can maintain minimum temperature and humidity ranges that meet ASHRAE-55. This requirement makes those points tricky for projects that do not have humidity control, especially in regions with high humidity. These points also require that you have a mechanical system with efficiency requirements listed in the CPG included in your project. For example, a project with 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 only will not be eligible for the credit, but a project with a split system will. 

    Option 2 is challenging because for a small CI project the cost of creating an energy model might outweighs the benefit of the potential energy savings achieved from using the model as a design tool. If the base-building has already developed a model, this is often more cost-effective. 

    It’s the scope that matters

    A typical HVAC installation in an office fit-out has a minimal scope. Often the base building’s mechanical systems supply the space with heating and cooling and ventilation air. What is left to the fit-out team is the distribution system which includes diffusersIn an HVAC context, diffusers disperse heating, cooling, or ventilation air as it enters a room, ideally preventing uncomfortable direct currents and in many cases, reducing energy costs and improving indoor air quality (IAQ). In light fixtures, diffusers filter and disperse light., VAV boxes, and controls. In LEED Interpretation #10134, issued on 11/1/11, USGBC clarified the level of HVAC equipment that must be installed to make a LEED-CI or LEED-Retail-CI project eligible for EAc1.3, Option 1, as being one of the following:

    • Air handlers with Variable Speed Controls complying with the requirements of the Core Performance Guide Section 3.10 that supply at least 60% of the total supply air volume used within the project scope.
    • Mechanical equipment that complies with the prescriptive efficiency requirements of the Core Performance Guide Section 2.9, and provides at least 60% of the cooling or heating capacity for the project scope.
    • The project can comply with the requirements of the credit if the project team can show that the relevant criteria have been met for all HVAC systems serving the area within the project scope, whether or not the HVAC systems are installed as part of the tenant scope of work.

    Another LEED Interpretation, #10135, further clarifies project scope for this credit, noting that "'project scope' refers to all spaces within the LEED project boundary, regardless of whether or not they are included in the project's scope of work. The project can comply with the requirements of the credit as long as all spaces within the 'project scope' satisfy the requirements."

    This Interpretation also notes, "Each private office must have its own active controls. Grouping of offices using a single control does not meet the intent of the requirements."

    FAQs for EAc1.3

    If pursuing Option 2, what is the scope of the energy model if the space shares a central plant, and what type of software should be used?

    If your space shares a central HVAC plant you need to model the whole building. Consider using energy modeling software, like eQuest, that can separately account for the energy use of the base building separately from your project space by adding additional electricity and gas meters for each space within the model. This is easier and more accurate to model and more likely to be accepted by GBCI reviewers.

    For Option 1, Zoning and Controls, is a thermostat considered an “active control capable of sensing space demand"?

    Thermostats alone do not meet this definition. LEED Interpretation 10242, issued 10/1/12, clarifies what is expected:

    • "Active control is the control capable of sensing space occupancy and adjusting the HVAC system demand based on the changes in space occupancy, which does not equal a thermostat or a separate thermal zone for each space."
    • "For VAV systems and non-VAV systems, active controls typically regulate the required outdoor air flow for ventilation, such as using demand controlled ventilation with CO2Carbon dioxide sensors in each private office and specialty occupancy space, or regulate temperature set point based on occupancy by adjusting the HVAC system to operate under the unoccupied set back when occupant sensors indicate that the space is unoccupied."
    • "Alternatively, VAV systems meeting all the requirements in LEED Interpretation 5273 are also eligible. However, those systems which do not modulate the system level supply air flow but only redirect the excess air back to the ceiling void or return air duct under low demand conditions are not eligible for this alternative compliance path."
    • "For a VRF system or another constant volume system with separate thermal zones for each specialty occupancy or private office, the following active controls would be considered sufficient to meet the credit criteria". (See Interpretation 10242 for the full guidance.)

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Pre-Design

Expand All

  • Both Options

  • The designer and mechanical engineer review the referenced sections of the Core Performance Guide (CPG). 

  • Decide which option best suits your project. Either way, you can only achieve 5 or 10 points, and nothing in between.

    • Under Option 1 you can earn points for using efficient equipment (5 points) and/or zoning and controls (5 points).
    • Under Option 2 you have to show energy savings using a computer-based energy model demonstrating a 15% cost savings from the ASHRAE 90.1-2007 baseline building for 5 points or a 30% savings for 10 points. 

  • Option 1: Equipment Efficiency & Appropriate Zoning and Controls 

  • Review sections 1.4, 2.9, and 3.10 in the Advanced Buildings: Core Performance Guide (CPG) to understand the requirements and how they relate to the systems to be installed in the project:

    • Section 1.4: Mechanical System Design – Perform project-specific load calculations during design to properly size mechanical equipment and to ensure efficiency and comfort by meeting ASHRAE-55 requirements for temperature and humidity.
    • Section 2.9: Mechanical Equipment Efficiency requirements – Meet or exceed the minimum requirements for efficiency for listed equipment in the CPG.
    • Section 3.10: Variable Speed Control – Provide variable flow capabilities for air and fluid systems by specifying variable speed fans and pumps with a motor horsepower of 5 hp or greater. 

  • You can only count HVAC components that are within the CI scope of work.

  • To achieve the first five points in Option 1 the design engineer has to demonstrate that the HVAC system in the space can maintain minimum temperature and humidity ranges that meet ASHRAE-55. This requirement makes those points tricky for projects that do not have humidity control, especially in regions with high humidity.

  • Review the zoning and controls requirements to see what it will take to achieve these five points (you have to meet all three requirements to earn any points):

    1. Each solar exposure (interior space with an exterior wall) has to have a separate control zone.
    2. All interior spaces separated by full, floor-to-ceiling partitions have to be separately zoned.  
    3. Private offices and other spaces with special occupancies must have active controls that can sense occupancy and modulate the HVAC system in response to demand, such as a CO2 monitor or occupancy sensor.

  • Note: If the base building HVAC system can’t be modulated in response to space demand, as with many VAV systems where one zone cannot be the control point of the entire air-handler’s outside air damper minimum position, the design has to meet the following criteria.

    1. The system has to be capable of modulating air-handling units (AHUs) and zone minimum supply volume below 0.30 cubic feet per minute per square foot of supply volume for standard VAV terminals, or below 22.5% of the peak design flow rate for fan-powered VAV boxes. For spaces where the minimum outdoor air flow exceeds the minimum supply volumes specified here, use occupant sensors or DCV to achieve these minimum supply volumes.
    2. The building control system has to include controls for fan static pressure reset.
    3. The mandatory requirements of ASHRAE 90.1-2007 and ASHRAE 62.1-2007 have to be met.

  • A “zone” implies an area with independent control of mechanical HVAC that typically includes its own thermostat and sensors to control air flow or temperature in a space. 

  • Identify each solar exposure and the spaces that correspond to those exposures that have to have a separate control zone. An “exposure” is an external wall that’s included in your project scope. Identify all the external walls in your floor plan, and indicate which direction each faces: north, south, east, or west.

  • Identify all interior spaces (those without an exterior wall) to be separately zoned. 

  • Identify all private offices and spaces with specialty uses—such as break rooms and conference rooms—to understand how many active controls you’ll need.  

  • Small (<200 ft2) private spaces intended for temporary occupancy like janitor closets, and mechanical rooms can be included as part of a larger zone. 

  • It’s a good idea at this stage to have your mechanical engineer meet with the base building engineer or manager to get detailed information on the possibility of adding controls and outside air intake—and to explore the possibilities of improving the efficiency of the system as a whole. The base building manager can also benefit from becoming familiar with the tenant’s design, which might lead to greater control and system integration.

  • Option 2: Energy Cost Reduction – 15%–30% 

  • Find out if it’s feasible to pursue this option. You’ll need to have (or be able to generate) a computer-based energy model running on approved software.

  • Option 2 is best for projects with unique mechanical systems and energy efficiency strategies that are not included in Advanced Buildings: Core Performance Guide, thus not fitting well with Option 1. 

  • If your project has a larger HVAC scope, one that includes boilers, chillers, or air handling units, it may make sense to develop an energy model to assist in system sizing and selection.

  • If energy modeling has already been initiated by the base building project team, this is the way to go. If your project is located in a LEED-certified building, it’s likely that an energy model has already been done. If so, check with your building’s owner about accessing the energy model files and results. 

  • It is not easy to achieve 15% or better energy cost savings over current energy codes, such as ASHRAE 90.1-2007, from space heating, cooling, fans, and pumps alone, even though you can factor in HVAC load reductions from envelope improvements and lighting in the equipment energy use calculation.

  • Developing a simulation model isn’t cheap—in the range of $10,000–$30,000 depending on the complexity of the project—but modeling can provide a favorable payback through design optimization and energy savings. 

  • Many CI projects with limited HVAC design scope find it more cost-effective to pursue Option 1. The usefulness of energy modeling as a design and optimization tool depends upon how wide the project scope is—the more systems that can be influenced in the design process, the better.

  • The energy modeler should be contracted during early design phase to provide recommendations for a high-performing system and equipment selection along with ideas about potential energy savings, cost estimates, and payback periods.  

  • Pursuing the energy model option can help you document compliance with the energy prerequisite. It can also be useful in applying for financial incentives, which are usually based on a percentage reduction (energy saved) relative to your local code.

Schematic Design

Expand All

  • Both Options

  • Include key HVAC efficiency targets in the Owners Project Requirements (OPR) document for commissioning (see EAp1 and EAc2), with input from the mechanical engineer and other design team members. Use metrics such as number of points to be achieved, HVAC efficiency levels, or HVAC percentage improvement over a baseline. Having those targets in the OPR will help the team develop a design strategy to meet goals for energy efficiency.

  • Strategize a design direction to meet these goals. Identify ways to reduce energy use by involving the mechanical engineer, architect, lighting designer, owner, and landlord in system design discussions. If applicable, explore passive design techniques within the scope of the interior fit-out. 

  • Encourage an integrated design that includes input from the design team and owners, as well as the architect, lighting designer, mechanical engineer, and others - to align space utilization, window treatments, lighting layout, and thermal zoning to create the most effective design.

  • Option 1: Equipment Efficiency & Appropriate Zoning and Controls 

  • Review the Core Performance Guide (CPG) for guidance on load calculations, mechanical equipment selection, and zoning and control requirements. The CPG is a manual that has a format similar to ASHRAE guidelines, so it is best interpreted by a design engineer.

  • Pay attention to these key points about implementing the requirements of CPG Section 1.4: Mechanical System Design:

    • Following ASHRAE-55 requires part-load and full-load calculations to ensure optimal efficiency while keeping occupants comfortable throughout the year.
    • For heating and cooling equipment, you need to perform load calculations with assumptions that are consistent with the CPG, including accurate characterization of lighting, solar gain, glazing performance, occupancy, and ventilation loads based on the specific design characteristics of the project. 
    • For ventilation equipment, you need to document fan-sizing calculations with zone-by-zone load calculations. 
    • To perform part-load calculations, use benchmark data, average daytime temperatures, non-peak solar gain, and other assumptions to define part-load conditions for the heating and cooling system. 

  • Describe the features of your design that can facilitate efficient operation at part-load conditions, and document how your system plans to maintain adequate ventilation air and comfort as required by ASHRAE-55. 

  • If your project is also pursuing IEQc 7.1: Thermal Comfort—Design, the procedures and documentation for that credit will also work for following CPG Section 1.4.

  • Following Section 2.9: Mechanical Equipment Efficiency, specify all systems within your project scope at performance efficiency equal to or higher than the minimum efficiencies listed in CPG Tables 2.9.1–2.9.6. 

  • Following Section 3.10: Variable Speed Control, specify variable speed drives on pumps and fans greater than 5 hp. 

  • In typical air-conditioned spaces, 20%–30% of energy used is for delivering the conditioned air to the space through ducts and fans. The volume of air depends on the load requirement, which varies with occupancy, latent heat load, and outside weather. Because of variations within all these parameters, delivered air volume should be modulated in occupied spaces with CO2 monitors, VAV boxes, or both to save energy.

  • The majority of space uses can benefit from variable air volume (VAV) distribution. Some projects, like warehouses and data centers, may not include variable load parameters and so would not save energy with VAVs. In those cases, you can provide a supporting narrative arguing against installing VAV. These less typical projects might benefit from following Option 2. 

  • Review zoning and controls compliance. Make sure that under the proposed mechanical design each interior space with a different exposure is a separate control zone, all appropriate interior spaces have been zoned separately, and that the required demand responsive controls are included.

  • If they haven’t done so already, have your design engineer develop a cost estimate for the additional zoning and controls required to meet the requirements. Consider whether the benefits in terms of energy savings and improved indoor air quality of the additional controls are worth the cost of installation.

  • Consider space programming in collaboration with mechanical system zoning. You may want to link similar functions together for mechanical zoning reasons. A floor with an open-plan office space that will only be occupied in the daytime can be controlled by one zone that allows for a reasonable degree of efficiency. On the other hand, if that open-plan office floor also has enclosed conference rooms and private offices, a single zone won’t allow users to adjust temperature and airflow to the enclosed rooms when they are unoccupied, so energy will be wasted.

  • If your project is installing a Building Management System (BMS), consider scheduling or occupancy sensors that reduce air flow and setback the air-conditioning temperature in unoccupied spaces. 

  • Option 2: Energy Cost Reduction – 15%–30% 

  • Engage an energy modeler to review the preliminary designs and make recommendations on programming and integration with existing systems. If you still have any options relating to orientation and shading, look at those as well.  

  • Give your energy modeler all relevant, energy-related information on the project, including glazing specifications, wall insulation, roof specifications, building uses on other floors, approximate lighting power use, site plan, and the operating schedule of base-building mechanical systems. Collecting this information will involve the owner, who can connect the energy modeler with the base-building engineer. You can use past energy bills to approximate the energy performance that needs to be input by the energy modeler.

  • Determine the energy model’s scope. In general, to simulate the performance of building systems an energy model has to include all spaces served by a common HVAC system. However, central HVAC systems often extend beyond the scope of CI projects. For example, if the project scope is a single floor fit-out in a four story building, it’s likely that the building HVAC systems will serve all four floors. The model will simulate the energy use of all four floors, but the CI project can account for only a portion (25% in this case) of the energy use and energy savings from efficiency upgrades.

  • Start the energy modeling by building the design-case model. Follow Section 11 (Energy Cost Budget) or Appendix G (Performance Rating Method) of ASHRAE 90.1-2007 guidelines for assistance with modeling parameters. Input the existing building’s envelope characteristics, but use project design specifications for energy-using equipment and systems. 

  • Using the Energy Cost Budget method may be more cost effective for your project, as it’s less comprehensive and detailed. However, it does not include savings for energy efficient air distribution systems. If this is where your project is expected to realize significant energy savings, use the Performance Rating Method.  

  • If your project is in a LEED-certified building, a model using the performance rating method may already exist and can be modified to document this credit. 

  • Modifications to the building HVAC system that are to be implemented concurrently with your project should also be included. (These modifications need not be within your project scope.) 

  • Create the baseline model. Two baseline model calculation methods are available; explore both to determine which one is better for your project:

    • Existing Conditions Baseline. This model includes the existing conditions of the building, but all systems must comply with the minimum ASHRAE 90.1-2007 efficiency guidelines. This calculation method is more beneficial for projects located in less-efficient buildings. Savings calculations for this model are adjusted to include only the area within the project scope or building segment.  
    • Alternative Baseline. This is intended for projects located in energy-efficient or LEED-certified buildings. For buildings that exceed the efficiency guidelines of ASHRAE 90.1-2007, the baseline can be adjusted down to the meet these guidelines. In addition, the calculations include the overall savings of the modeled HVAC system and are not adjusted relative to the project area or building segment. These adjustments are allowed so the project isn’t penalized for being in an efficient, possibly LEED-certified, building.  

  • The operational performance of the base building affects the performance of the tenant space. Sometimes the current operator doesn’t know the specifications of the base-building systems that are being modeled, so request as much information as you can, including operations and maintenance manuals that might provide more details. 

  • If pursuing Option 2, and you need to model the whole building because your space shares a central HVAC plant, consider using energy modeling software, like eQuest, that can account for energy use of the base building separately from your project space.  This is more likely to be accepted by the reviewers.

Design Development

Expand All

  • All Options

  • Reduced energy loads can translate into lower construction costs because you might be able to get by with smaller equipment; including fans, pumps and auxiliary systems; and less ductwork. 

  • Option 1: Equipment Efficiency & Appropriate Zoning and Controls 

  • Review the following sections of the Core Performance Guide (CPG) and credit requirements:

    • Section 1. 4 – Check that the part-load calculations have been completed and that compliance with ASHRAE-55 has been confirmed.
    • Section 2.9 – Ensure that your project’s mechanical design and equipment comply with the CPG efficiency requirements.
    • Section 3.10 – Verify that the highest efficiency fans and pumps have been identified. Variable frequency drive pumps and variable air volume (VAV) distribution systems can be used to address fluctuating demand. Sensors and controls to measure air volumes and reduce energy waste during low occupancy should be installed. 
    • Appropriate Zoning and Controls – Further develop designs for the separate zones and controls to be installed. Confirm that these meet the requirements. 

  • Option 2: Energy Cost Reduction – 15%–30% 

  • Early in design development, engage the energy modeler in reviewing the recommendations for reaching the 15% and 30% energy reduction thresholds. See the LEED-NC energy modeling guidelines for an overview of the energy modeling process and specific guidance on creating the energy model. 

Construction Documents

Expand All

  • All Options

  • Call out the efficiency ratings of selected equipment on mechanical equipment schedules to make sure that the proper model is selected and that the system is installed according to design intent.

  • Option 1: Equipment Efficiency & Appropriate Zoning and Controls

  • Ensure that your project is in compliance with all the prescriptive requirements outlined in the Advanced Buildings: Core Performance Guide, Sections 1.4, 2.9, and 3.10. Complete the prescriptive checklist, and collect equipment cut sheets.  

  • This is an all-or-nothing option: If even one requirement is not met, all five points are lost.

  • Develop drawings and specifications for the zones and controls.

  • Option 2: Energy Cost Reduction – 15%–30% 

  • Ensure that specified HVAC systems and components match or exceed the efficiency requirements of the systems in the final, accepted energy model. Also, ensure that these systems, with their corresponding performance ratings, are included in the appropriate schedules and plans.

Construction

Expand All

  • Confirm the installation of the selected equipment. 

  • Document the credit requirements on LEED Online, per the option you selected.

  • For Option 1: Equipment Efficiency & Appropriate Zoning and Controls, document the following:

    • Section 1.4 - Upload a summary of load calculations for heating, cooling and fan sizing, including assumptions and results at full load and part load.
    • Section 2.9 – Have your mechanical engineer sign off on the template that the efficiency requirements have been met. 
    • Section 3.10 – Fill out the template with the variable speed fans and pumps included in the project, their location, and design wattage demand at 50% of design flow. 
    • Appropriate Zoning – Indicate that all requirements for zoning have been met on the template. Also, include a narrative that describes the building-level HVAC system as well as that serving the tenant space, how the zones were determined, the control logic, as well as anticipated energy savings. 

Operations & Maintenance

Expand All

  • Monitor equipment energy use over time to confirm that the projected savings are achieved.  

  • Engage a commissioning authority as part of EAc2: Enhanced Commissioning.

  • USGBC

    Excerpted from LEED 2009 for Commercial Interiors

    COPYRIGHT © 2009 BY THE U.S. GREEN BUILDING COUNCIL, INC. ALL RIGHTS RESERVED

    EA Credit 1.3: Optimize energy performance - HVAC

    5-10 Points

    Intent

    To achieve increasing levels of energy conservation beyond the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use.

    Requirements

    Option 1

    Implement 1 or both of the following strategies:

    • Equipment Efficiency—(5 points)

      Install heating, ventilation and air conditioning (HVAC) systems that comply with the efficiency requirements outlined in the New Building Institute’s Advanced Buildings™ Core Performance™ Guide Sections 1.4: Mechanical System Design, 2.9: Mechanical Equipment Efficiency and 3.10: Variable Speed Control.
    • Appropriate Zoning and Controls: (5 points)

      Zone tenant fit out of spaces to meet the following requirements:
      • Every solar exposure must have a separate control zone.
      • Interior spaces must be separately zoned.
      • Private offices and special occupancies (conference rooms, kitchens, etc.) must have active controls capable of sensing space use and modulating the HVAC system in response to space demand.

    OR

    Option 2

    Reduce design energy cost compared with the energy cost budget for regulated energy components described in the requirements of ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1). Projects outside the U.S. may use a USGBC approved equivalent standard2.

    AND

    Path 1 (5 points)

    Demonstrate that HVAC system component performance criteria used for tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. are 15% better than a system in minimum compliance with ANSI/ASHRAE/IESNA Standard 90.1–2007 (with errata but without addenda1) or USGBC approved equivalent.

    OR

    Path 2 (10 points)

    Demonstrate that HVAC system component performance criteria used for tenant space are 30% better than a system that is in minimum compliance with ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda1) or USGBC approved equivalent.

    Potential Technologies & Strategies

    Design the HVAC system components to maximize energy performance. Review compliance options for EA Credit 1.3 and determine the most appropriate approach. Option 1 provides a more prescriptive approach to recognizing energy-efficient HVAC design, while Option 2 is performance based.

    FOOTNOTES

    1. Project teams wishing to use ASHRAE approved addenda for the purposes of this credit may do so at their discretion. Addenda must be applied
    consistently across all LEED credits.

Web Tools

Energy Analysis Tools

This website discusses the step-by-step process for 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.

ASHRAE 2007 HVAC Compliance Forms

Key forms for this credit include the following: Standard 90.1-2007: HVAC Compliance Documentation (PDF), part 1; Standard 90.1-2007: HVAC Compliance Documentation (PDF), part 2; Standard 90.1-2007: HVAC Compliance Documentation (PDF), part 3; Standard 90.1-2007: HVAC Compliance Instructions (PDF).

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.

HVAC Design Narrative

Option 1

This example narrative of HVAC system serving the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. and the building level system describes how the zones and controls were determined, and anticipated energy savings.

HVAC Construction Documents

Options 1 and 2

The full HVAC system plans and specifications shown in this example demonstrate compliance with credit requirements.

HVAC Load Calculations

Option 1

These examples of summary load calculations for the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. show assumptions and results at full- and part-load, and compliance with ASHRAE-55.

CI-2009 LEED Online Sample Forms – EA

The following links take you to the public, informational versions of the dynamic LEED Online forms for each CI-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):

Version 3 forms:

These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions for these forms; for more information, visit LEED Online and click "Sample Forms Download."

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

200 Comments

0
0
Nick Chiarelli
May 08 2013
Guest

Partial Load Calculations & Fan Sizing

Hello,

This project is 12 floors served by base building 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, pumps, chillers, etc. Our scope was the tenant fitout of each floor while reusing the main base building systems feeding the floors. We installed fan boxes, 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, heat pumps and transfer fans. Will the "total tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. fan & pump sizing" only include the fans that are located on the floors we did work on, or will they have to include the fans and pumps associated with the base building AHU's, Chillers, Boilers, etc.?

Also, I have the load calculations from Carrier HAP but am not sure how to get the partial load condition calculations complete. Any advice?

Thanks,

Nick

1
1
0
Dylan Connelly Mechanical Engineer, Integral Group May 09 2013 LEEDuser Expert 2976 Thumbs Up

Nick,
We typically use Trane, but I assume you can do it the same way. Instead of running the loads for the worst case time of year. Run the loads for a mild time of year. Such as April. This will give you a partial load condition.

Post a Reply
0
0
Jimena Etchegaray Architect GREENM
Apr 29 2013
LEEDuser Member

EAc1.3 Simulation for LEED CI

HELLO.
We have a project that will be applying for LEED certification under CI for Retail. This project is supermarket within a mall, the retail space is rented. We have the following doubts for EA c1.3 using the second option ASHRAE APENDIX 11:
- is it necesary to simulate the whole mall, or jus the retail space that is under certification, in this case the supermarket.
- The Supermarket HVAC system consists in 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., and these AHU are supplied with cold water that comes from the HVAC central of the mall. For the proposed supermarket case, is it necesary to simulate the mall thermal central? or how do you suggest we should indicate the cold water that comes from the mall AHU?

1
1
0
Marcus Sheffer LEED Fellow, 7group Apr 30 2013 LEEDuser Expert 19813 Thumbs Up

We ran into this situation on a mall project as well. Technically the published information indicates that you have to model the whole mall. I think this is completely impractical and virtually impossible to do at any kind of reasonable cost.

What makes sense is to model the chilled water as purchased energy or down-size the central plant and create a virtual plant using the same efficiencies and losses from the actual plant like option 2 in the DES. Which one makes the most sense depends on if the chilled water is provided as part of the lease cost or if it is metered and billed separately.

We ended up recommending to our client that they submit a LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. but we did not hear if they actually did or not.

Post a Reply
0
0
Srimannarayana NCVK ESD Consultant
Mar 13 2013
Guest
151 Thumbs Up

CAV - How to meet section 3.1 requirement

Hi,

For one of my LEED CI project, air distribution is a CAV system. There is a VFDA variable frequency drive (VFD) is a device for for controlling the speed of a motor by controlling the frequency of the electrical power supplied to it. VFDs may be used to improve the efficiency of mechanical systems as well as comfort, because they use only as much power as needed, and can be adjusted continuously. for 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. though. To document EA c 1.3, i need to meet CPG requirement. But Sec 3.1 of core performance guide specifically says that VFD should be for 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. systems. In this regard can i still meet the compliance by showing VFD for CAV system? Please clarify

Thanks
Sriman

1
1
0
Rudolph Carneiro HVAC consultant, Sustentech Mar 21 2013 Guest 158 Thumbs Up

I'm guessing you meant section 3.10 and not 3.1? I'd say that they are not applicable since the VFDA variable frequency drive (VFD) is a device for for controlling the speed of a motor by controlling the frequency of the electrical power supplied to it. VFDs may be used to improve the efficiency of mechanical systems as well as comfort, because they use only as much power as needed, and can be adjusted continuously. will never ramp down the AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. to 50% of it rated flow. The VFD in this case reduces the energy consumption and maintins flow with small flutuations in fan speed, but should not go as far down as 1/2 the flow rate.

Post a Reply
0
0
Kasandra Martin Designer
Mar 12 2013
Guest
17 Thumbs Up

Gas Rooftop HVAC

Are there any guidelines with LEED CI for having gas fired rooftop hvac units?

1
3
0
Daniel LeBlanc Senior Sustainability Manager, YR&G Mar 25 2013 LEEDuser Expert 578 Thumbs Up

There is some language in section 2.9 of the Core Performance guide that deals with gas furnaces. You would be best to review the CPG and ensure that your equipment meets the requirements.

2
3
0
Kasandra Martin Designer Mar 26 2013 Guest 17 Thumbs Up

Where can I find the CPG? I have the reference guide for LEED CI. I will be going for option 2 of EA 1.3 so I don't reference that for it.

3
3
0
Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Mar 26 2013 LEEDuser Moderator

Kasandra, the CPG is listed as one of the Resources under the tab above.

Post a Reply
0
0
Alejandro Rivera Rivera Junior Engineer Studio Domus
Feb 26 2013
LEEDuser Member
5 Thumbs Up

Do we need to document out of scope HVAC equipment?

I am working on a project where all of the AHUs, except for one, are provided by the building owner. Thus, the scope of work is limited to the provision of one AHU (for the IT Room), the redistribution of existing units, and the ductwork.

My team would like to pursue OPTION 1 (Equipment Efficiency). In order to do this, do we need to document out of scope HVAC equipment? Or would it suffice to provide project-specific load calculations for the IT Room only, in order to comply with Section 1.4 of the Advanced Building Core Performance Guide?

Thanks for your help.

1
1
0
Daniel LeBlanc Senior Sustainability Manager, YR&G Mar 25 2013 LEEDuser Expert 578 Thumbs Up

Yes, you can document out of scope equipment that serves the project space if it meets the requirements. From what you've described, it seems that you would likely need to do so if your project scope has only one 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. for the IT room because it likely will not meet the 60% of the total supply air volume threshold. In that case, all HVAC system serving the space would need to meet the requirements.

Post a Reply
0
0
Marco Abdallah
Feb 21 2013
LEEDuser Member
298 Thumbs Up

"relevant criteria"

The project can comply with the requirements of the credit if the project team can show that the relevant criteria have been met for all HVAC systems serving the area within the project scope, whether or not the HVAC systems are installed as part of the tenant scope of work.

What is meant by "relevant criteria"? Do the HVAC systems have to comply with EAp2, Min. Energy Perf. to be used in this credit?

1
3
0
Marcus Sheffer LEED Fellow, 7group Feb 21 2013 LEEDuser Expert 19813 Thumbs Up

The relevant criteria refers to the issue LEED requires you to address. For example if following Option 1 Equipment Efficiency you can earn those points if the HVAC systems meets the requirements and it does not matter if the equipment in question was part of the tenant scope or work or not.

2
3
0
Marco Abdallah Feb 21 2013 LEEDuser Member 298 Thumbs Up

Ok, when following Opt 1 it seems to be clear. But what about Option 2 - the requirement by Opt 2 is to is to meet at least 15 % energy savings, there are no individual requirements for the devices in Opt 2.

Example: Central HVAC-systems are not included in the tenant scope. However we would like to pursue EAc1.3. Unfortunately the COP of the chiller in the basebuilding does not fulfill the minimum requirements of EAp2. If our simulation results in an energy saving > 15 % are we eligible for this credit?

3
3
0
Marcus Sheffer LEED Fellow, 7group Feb 21 2013 LEEDuser Expert 19813 Thumbs Up

Can you even get to 15% HVAC savings with a non-compliant chiller?

Since the chiller is not in the tenant scope it does not have to comply with the mandatory provisions under the prerequisite. Option 2 does not require compliance with the mandatory provisions in the credit language so if you can show the 15% I would think you could earn the points under this credit. I am not sure if this would be prohibited elsewhere like in the Reference Guide so you should check to be sure.

Post a Reply
0
0
Marco Abdallah
Feb 15 2013
LEEDuser Member
298 Thumbs Up

Option 2: Scope and EAp2

1) Is it possible to pursue option 2 even if all the central HVAC systems are not part of the tenant scope of work?
2) Is it possible to use the simulation (option 2) according Ashrae Appendix G also for EAp2, Minimum Energy Performance like in other rating systems?

Post a Reply
0
0
Lavanya Veerappa Ms LEAD Consultancy & Engineering services
Feb 12 2013
Guest
61 Thumbs Up

Active control modulating the HVAC system as per space demand

Does that mean a dedicated 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. box hooked with any one of the following meets the requirement:

1. Thermostat control
2. Occupancy sensor
3. CO2Carbon dioxide sensor

If the answer for option 1 or 2 is yes, then how is it going to modulate HVAC system as per space demand ? because thermostat only senses the temperature and occupancy sensor will only shut off/on the VAV and pump in fresh air as designed. However it will not help in pumping more fresh air if the occupancy increases (I assume that is what the space demand is)

I hope my interpretation is correct ?

1
3
0
Marcus Sheffer LEED Fellow, 7group Feb 12 2013 LEEDuser Expert 19813 Thumbs Up

The Bird's Eye View FAQ section above summarizes Interpretations around this issue. Looks like just thermostats do not cut it.

2
3
0
Lavanya Veerappa Ms, LEAD Consultancy & Engineering services Feb 18 2013 Guest 61 Thumbs Up

When themrostat can meet the space demand by modulating the VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. is there any requriement for other any active control components like occupancy sensor ?

3
3
0
Marcus Sheffer LEED Fellow, 7group Feb 18 2013 LEEDuser Expert 19813 Thumbs Up

Suggest you read the interpretations mentioned above (10242 and 5273) then request clarification if necessary. I can't tell if your system meets the criteria outlined in the interpretations based on what you have provided.

Post a Reply
0
0
Lavanya Veerappa Ms LEAD Consultancy & Engineering services
Feb 11 2013
Guest
61 Thumbs Up

LEED CI for Data center project

Hi,

A data centre project that i am working for is applying for LEED CI. We are planning to work on option 1 - prescriptive approach to meet enhanced energy performance.

We have considered VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. system with CO2Carbon dioxide sensor for all private offices, conference rooms and have provided separate zone for solar exposed areas. Also the mechanical system efficiency is considered as per CPG. However the zoning control is provided only for the office areas of the project. Is it mandatory to provide zoning control for unoccupied areas such as server rooms ? Also there is no guidelines given for equipment efficiency for CRAC units in CPG. Am i missing out on anything here..

1
9
0
Marcus Sheffer LEED Fellow, 7group Feb 11 2013 LEEDuser Expert 19813 Thumbs Up

No need for zoning controls in unoccupied spaces. CRAC efficiency in not covered by 90.1-2007. It is covered by 90.1-2010 Table 6.8.1K.

2
9
0
Lavanya Veerappa Ms, LEAD Consultancy & Engineering services Feb 12 2013 Guest 61 Thumbs Up

Thanks for the reply Marcus. I want to be more clear, the CRAC unit is connected to central plant which has air cooled screw chillers serving only critical load.

Does that mean i will have to meet efficiency of CRAC unit as per ASHRAE 90.1 2010 or will i be through with this credit (prescriptive approach) if i just meet the efficiency of the air cooled chillers as per CPG?

Or should i meet efficiency of both ?

3
9
0
Marcus Sheffer LEED Fellow, 7group Feb 12 2013 LEEDuser Expert 19813 Thumbs Up

Just the screw chillers would need to comply.

4
9
0
Lavanya Veerappa Ms, LEAD Consultancy & Engineering services Feb 15 2013 Guest 61 Thumbs Up

Thats great !! Thanks Marcus.

5
9
0
Cassini Kit Sustainability Consultant Feb 28 2013 Guest 25 Thumbs Up

Hi, I am currently working on a data center project also.
May I know if the CRAC unit contains compressor, that means it should be regarded as a air-cool chiller. Is it true that it has to comply with requirements in ASHRAE 90.1 2007 package-type type AC?
If no, are there any reference published by USGBC that it is not in the scope of LEED-CI 2009 version?

thanks very much.

6
9
0
Marcus Sheffer LEED Fellow, 7group Mar 01 2013 LEEDuser Expert 19813 Thumbs Up

Technically this type of unit is not covered by 90.1-2007 so there is no minimum efficiency it must meet. I would look to 90.1-2010 which includes this type of unit for minimum performance criteria.

7
9
0
Cassini Kit Sustainability Consultant Mar 07 2013 Guest 25 Thumbs Up

Hi Marcus, I just send an email to discuss with some staff in USGBC informally about the case of CRAC units with compressor. Then they refer to some specific technical team to review this case. And I asked if possible to adopt the requirement of CRAC units in ASHRAE 90.1 2010.

However, they answered that since there is no specific requirements in Core performance guide and LEED-CI rating system, it may not be excluded. They only suggest us to submit a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide to the LEED project review team for their official answer.

But you know if we apply a CIR, LEED review team may need 1-2 months to process and replied us 2 months later. The project schedule is tight that we can't wait for this..

So properly we have to change our design now.

8
9
0
Marcus Sheffer LEED Fellow, 7group Mar 08 2013 LEEDuser Expert 19813 Thumbs Up

So they said it can't be excluded but they would not tell you what minimum efficiency you needed to meet?

The least risky, most conservative and right thing to do path would be to make sure your units meet the minimums in 90.1-2010.

9
9
0
Amy Boyce Manager, LEED, USGBC Mar 08 2013 Guest 184 Thumbs Up

Cassini,
I'm sorry that the team was not able to provide a better answer without a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide. Since I don't know the details of the project, I will not weigh in on that, but I can tell you that the turn-around time for a project-specific CIR is 3 to 4 weeks. I don't know if that fits within your time frame, but I just wanted to let you know.

Post a Reply
0
0
Marco Abdallah
Feb 05 2013
LEEDuser Member
298 Thumbs Up

District Energy Systems: Confusion

We are working on a CI-Certification of a tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. (5 floors) in a highrise building with around 40 floors. The tenant does not have influence on the central HVAC system.
The main building is connected to a district heating system. Cold production is provided by central chillers and ice storage.

We modelled the tenant space with purchased heat. That means that we used typical local energy rates for heating, cooling and electricity without considering how the hot or cold water is produced.
However we now received a review comment which states that we should use the "Treatment of District or Campus Thermal Energy in LEED v2 and LEED 2009". Table 1 (EAc1 points restrictions) of this document points on Appendix A which says: "For Projects under the LEED-CI rating system DES have no effect on any EA section prerequisites or credits."

For me this means that the district heating as well as the cold production of the basebuilding does not have to be considered in EAc1.3.

Do we have to model the Proposed and Baseline Case with the standard boiler and chiller according ASHRAE?
OR
Should we model the tenant space with purchased heat according ASHRAE 90.1.2007, App. G3.1.1.1 Purchased Heat using typical energy rates? This would actually be same the approach as we already used.

Post a Reply
0
0
Mario Leonhardt
Jan 27 2013
Guest
2 Thumbs Up

Question

Can the LEED-CI certificate be obtained even after the renovation process has been completed? There has been no registrations or whatsoever before the renovation/construction.

Thank you for any help you can provide.

1
1
0
Marcus Sheffer LEED Fellow, 7group Jan 29 2013 LEEDuser Expert 19813 Thumbs Up

Yes it is possible assuming you took the actions necessary during design and construction to meet the prerequisites and earn enough points.

Post a Reply
0
0
Mark Taake United Excel Design
Dec 20 2012
LEEDuser Member
6 Thumbs Up

active control for private offices

I'm beginning to think that in many cases the private office active control requirement can be made to work for a VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. system only if each office has a separate motorized damper in the supply duct serving it along with an individual space temperature sensor. Given an example where three offices with similar zoning characteristics are served by a single air terminal, then the occupancy sensor would need to shut off air to the space via the motorized damper so that the other two (occupied) offices could continue to be served while the third office occupant went to a meeting. But if these offices had an exterior wall/glass exposure, east, for example, then control of space temperature would be lost during the period of unoccupancy unless each office also had a space temperature sensor which would act to override the occupancy sensor when the room temperature went out of range. A person going to a 2 hour meeting starting at 8:30 would come back to a very uncomfortable room, negating the ability to comply with ASHRAE 55. The alternative would be for each of these offices to have an air terminal unit. I don't mean to make this complicated but I see no other way of doing this. Am I missing something?

1
1
0
Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jan 16 2013 LEEDuser Moderator

Mark, this is not my area of expertise. However, I think that 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. 10242 might be of some guidance to you. Key parts of it are quoted above under LEEDuser's Bird's Eye View.

Post a Reply
0
0
Mark Taake United Excel Design
Dec 20 2012
LEEDuser Member
6 Thumbs Up

3 questions

Our project involves multiple renovations of areas within a large hospital. We are applying under CI rather than Healthcare because the project is not a total gut. Our intent is to follow Option 1 under EAc1.3.
QUESTION 1: CPG section 1.4 talks about "sizing heating and cooling equipmentThe equipment used for cooling room air in a building for human comfort.". The building is served by numerous central station 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. AHUs which our intent is to reuse (assuming our load calculations will support that, which we believe they will). On that basis, the project will not have any new equipment, other than VAV terminals where zoning requirements will not allow reuse of existing. This doesn't invalidate our ability to comply with 1.4, does it?
QUESTION 2: Regarding the zoning/control criteria, I had been under the belief that statement "interior spaces must be separately zoned" meant separately zoned from spaces with solar exposures. In the Checklist online there's a statement "all interior spaces separated by full, floor-to-ceiling partitions have to be separately zoned". Surely not from each other? If we have 3 identical interior spaces (e.g., all offices or all exam rooms) this doesn't mean there would need to be 3 different VAV terminals controlled by 3 different space thermostats, does it?
QUESTION 3:The hospital is served by a central plant of hot water boilers and centrifugal chillers. Because this plant serves the entire building, the capacity is considerably larger than what is needed to serve just our total project's work area. How does this get addressed when we fill out the compliance form?

1
1
0
Dylan Connelly Mechanical Engineer, Integral Group Jan 21 2013 LEEDuser Expert 2976 Thumbs Up

Mark,
Great questions.
1: This is discussed above under the section "It's the scope that matters." This section should give you your answer.
2: I have seen this statement interpreted as from each other by the LEED Reviewers. Regardless, if as you stated, you have 3 identical offices or exam rooms they would need to be separately zoned per the next requirement: "Private offices and special occupancies must have active controls...."
3: The form asks for your to input only your project space load and project space capacity. This would be the percentage of the base build's system that your project is going to use. Under "Criteria 3.10 it would appear that your input the fully size of the equipment.

Post a Reply
0
0
Marina Horchin ESD
Nov 30 2012
Guest
39 Thumbs Up

CIv2009: Advanced Buildings Core Performance Guide (CPG)

Hi Everyone,
We have two different versions of the CPG! One with " Printed Date: July 2007" and one "Revised Edition 1.11, July 2011" that have completely different required efficiencies for mechanical systems. The reference guide, LEEDonline forms or the CIRs fail to address that. Which one should we use to meet the intent of EAc1.3 Option 1?
Thanks,

1
4
0
Erik Dyrr Director, Sustainable Buildings and Operations, KEMA Nov 30 2012 Guest 347 Thumbs Up

We have always used the July 2007 version. I haven't seen an addendum or interpretation from USGBC about an update.

2
4
0
Marcus Sheffer LEED Fellow, 7group Dec 03 2012 LEEDuser Expert 19813 Thumbs Up

Yep the one in effect when LEED 2009 came out is the one you must use. However if you used to more recent one it would likely be approved.

3
4
0
Marina Horchin ESD Dec 03 2012 Guest 39 Thumbs Up

Thank you Marcus and Erik. We'll do just that. Since there is no specific guidance on the versions, I'll assume the older one will work just fine.
Thanks again.

4
4
0
Kasandra Martin Designer Dec 27 2012 Guest 17 Thumbs Up

http://www.powells.com/biblio/9780974296913?page=customercomments#produc...
Is this the book you are referring to? I need to buy this and want to make sure it is only available to purchase and wasn't available online to view somewhere.

Post a Reply
0
0
Orlin Velinov, PE Mechanical Engineer Termo Aire, LTDA
Nov 14 2012
LEEDuser Member
175 Thumbs Up

Naturally Ventilated Space

We have a tenant renovation project within existing building. Currently the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. does not have air conditioning system and is naturally ventilated. As part of the renovation the tenant is planing to add series of external shading devices to improve the comfort withing the tenant space and enhance the natural ventilation strategies that the existing space already has. The existing space has what appears to be well thought strategies for cross ventilation through operable window and operable ventilation openings with louvers and open floor plans with internal atrium enhancing the natural ventilation flow paths. The question is if there is any way we can take credit and get points under EAc1.3 for not providing AC? Any ideas how we can document such energy savings are welcome. As an idea, we can try to use energy simulation software such as Energy Plus or Design Builder which have capabilities to simulating natural ventilation and indoor conditions due to the natural ventilation and external shading strategy. We hope to be able to show that such conditions are in accordance with the thermal comfort requirements of ASHRAE 55 Section 5.3. On a separate model we can then run baseline with AC per ASHRAE 90.1 and proposed as designed and without AC, while both models use the same thermostat 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. equal to the one from the natural ventilation simulation, Looking at the ASHRAE 55, for the mean monthly outdoor temperatures we have in our climate we can maintain up to 80 deg.F indoor temperature and it would be considered within 90% acceptable limits! However, this method is a bit complicated and may be cost prohibitive for the about 3000 sq.ft. tenant space project we have. Any ideas and/or previous experience with similar documentation approach and requirements are appreciated.

Post a Reply
0
0
gustavo goldman
Oct 30 2012
Guest
170 Thumbs Up

solar exposure

The building has one of the facades facing east-south. There are trees at street level that block the sun. Also the prject is located in a densily built area with tall buildings that eventually block the sun . Would we need to control this specific zone with a sperate control being that the exposure would be minimal?

1
1
0
Marcus Sheffer LEED Fellow, 7group Oct 30 2012 LEEDuser Expert 19813 Thumbs Up

Yes I would think so. The reason for zoning the perimeter is not just relative to solar exposure. The perimeter also has greater conductive heat loss to the exterior. So the need for zoning could be climate dependent - if no heating is required and the solar exposure is zero it may not be necessary but that would be a pretty rare case.

Post a Reply
0
0
Keith Amann Sr. Sustainability Manager YR&G
Oct 24 2012
LEEDuser Member
585 Thumbs Up

accounting for equipment not listed in CPG tables

The Core Performance Guide, and it's reference standard (Consortium for Energy Efficiency Commercial Unitary AC and HP Specification) has no standard for large (760 kbtu/h) systems. Table 2.9.2 of the CPG only includes water cooled heat pumps < 135,000 Btu/h. Are these heat pumps not required to comply with this table? There is no other listing in the table that applies to this type and size unit, WSHP's cooled by a cooling tower (no chiller). The section states that equipment not listed shall be energy star, but this type of equipment is not energy star eligible.

Does the lack of a referenced baseline system type make a project ineligible for the credit following Option 1, or can an alternative approach be used to show equipment efficiency above what would be considered "standard performance" for a given piece of equipment?

1
1
0
Marcus Sheffer LEED Fellow, 7group Oct 25 2012 LEEDuser Expert 19813 Thumbs Up

I would think that means you would need to use Option 2 if the equipment is not covered by the CPG.

Post a Reply
0
0
Tiombe Parrish Sustainable Design Coordinator Jacobs GBNA
Oct 22 2012
LEEDuser Member
90 Thumbs Up

EER requirement and VFD air cooled equipment - Help

We have a proposed LEED Silver office building under LEED 2009 for Commercial Interiors. The intention is to follow NBI Advanced Buildings Core Performance Guide for EA Credit 1.3 Optimize Energy Performance-HVAC. Our stumbling block is an air-cooled chiller that was added for the computer room air handling units in the tenant fit-out. The chiller is a McQuay Pathfinder, Air-Cooled Rotary Screw Chiller with VFDA variable frequency drive (VFD) is a device for for controlling the speed of a motor by controlling the frequency of the electrical power supplied to it. VFDs may be used to improve the efficiency of mechanical systems as well as comfort, because they use only as much power as needed, and can be adjusted continuously.. The capacity is 272 tons. The NBI guide requires compliance with both full load (1.2 kw/ton) and IPLV (1.0 kw/ton).

My chiller is 1.5 kw/ton full load and 0.68 kw/ton IPLV. So it’s a bust at full load. Even at 75% part load I’m already down to 0.8 kw/ton.

It appears the NBI guide doesn’t give consideration for VFD machine until your’e up into a centrifugal water cooled.

So I’m left concluding that my vfd chiller cant even meet their requirements of a standard air-cooled.

The other rub on the design is a 105 degree ambient. When running the machine selection at standard design, 95% capacity gets the 272 tons required with a 10.3 EER. Unfortunately the full load capacity of the machine at standard design conditions is 288 tons at and EER of 9.6.

Has anyone run into this situation in the past and had a successful credit?

1
1
0
Marcus Sheffer LEED Fellow, 7group Oct 25 2012 LEEDuser Expert 19813 Thumbs Up

Perhaps Option 2?

Post a Reply
0
0
M.S. Chan PM BAI
Oct 19 2012
LEEDuser Member
29 Thumbs Up

Heat Pump for Domestic Water Heating

We are using heat pumps for domestic water heating. (The water source will be from the campus/district condenser water system.) Can we take credit in the energy calculations using heat pumps? If so, how is this modeled?

1
1
0
Marcus Sheffer LEED Fellow, 7group Oct 25 2012 LEEDuser Expert 19813 Thumbs Up

Not under this credit as all energy use not related to HVAC is held as neutral and cannot contribute savings.

Post a Reply
0
0
Victor Avedano Principal JALRW Eng. Group Inc.
Oct 17 2012
LEEDuser Member
102 Thumbs Up

Option 1 Zoning for a CI- Facility with out of scope areas withi

Good afternoon. We are currently submitting templates for a University facility. Under this credit we decided to go with Option 1 (Zoning and Controls) (5 points only) but there is a little bit of confusion since there are some interior areas in the building that are out of the scope while the building still classifies as CI. Basically the question would be, how can we or should we demonstrate compliance of these areas? Should we submit a tentative zoning for these areas even though the sizing of the equipment do not reflect this info? or should we submit these areas as having one or two zones (depending on the closeness to natural lighting) even though it does not really show any type of energy optimization and the conditions might change in the future?

1
1
0
Marcus Sheffer LEED Fellow, 7group Oct 25 2012 LEEDuser Expert 19813 Thumbs Up

If the area is outside the scope of the CI project I don't think it needs to comply but maybe I am missing something.

Post a Reply
0
0
Noriko Yasuhara CSR Design & Landscape Co., Ltd.
Sep 24 2012
LEEDuser Member
348 Thumbs Up

Mechanical Efficiency Requirements - Energy Star

Hi,

The Advanced Buildings Core Performance Guides asks for ENERGY STAR labeled package unitary equipment.

Does anyone has experience with ENERGY STAR "equivalent" equipment adoption in international projects?

Thanks in advance,

1
1
0
Scott Adams Architectural Standards Specialist, Starbucks Coffee Company Sep 24 2012 Guest 83 Thumbs Up

Yes, I have been able to get equipment accepted by showing to would be able to meet Energy Star requirements in Energy Star labeling was available. You would need to provide a comparative analysis of the equipment specs to the Energy Star standard and you would have to show that Energy Star labeled equipment is not available. You are most likely going to have to go through a project specific CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide though.

Post a Reply
0
0
John Kitsalis Principal New England Engineering, Inc.
Sep 18 2012
LEEDuser Member
64 Thumbs Up

Equipment Efficiency Section 1.4

This section is a little confusing and I am putting my interpretation of it up. Please let me know if I am correct.

Total Project Space Load (heating/cooling):
I did load calculations for the entire building and put the peak space load here.

Total Project Space Equipment Capacity (heating/cooling):
I added up all of the installed or designed equipment capacities here.

Total tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. fan and pump sizing:
I have no interpretation for this. In need of help.

1
1
0
Dylan Connelly Mechanical Engineer, Integral Group Sep 19 2012 LEEDuser Expert 2976 Thumbs Up

For "fan and pump sizing" we add up the total fan and pump capacity within the project scope (kW or hp).

Post a Reply
0
0
Rudolph Carneiro HVAC consultant Sustentech
Aug 07 2012
Guest
158 Thumbs Up

Solar exposures and efficiency

1) Is there an exception for small corner offices?
The office is about 90 square feet. The 2 solar exposures are north and east facing. The office will have it's own dedicated split highwall. The rest of the floor has many splits for many different rooms.
2) The split highwall has a SEER of 13.72. Are the reviewers really picky about the 14 SEER requirement from the advanced buildings CPG?

1
2
0
Marcus Sheffer LEED Fellow, 7group Aug 07 2012 LEEDuser Expert 19813 Thumbs Up

I am not aware of any exceptions. The prescriptive requirements must be met if following that option is my understanding.

2
2
0
Richard Manning Principal, Green Building Services Oct 30 2012 LEEDuser Member 23 Thumbs Up

The LEED Credit Form does not specifically require documentation of the SEER rating as it noted in the CPG.

Post a Reply
0
0
Luke Knapp P.E. Midwest Engineering Professionals
Jul 31 2012
Guest
24 Thumbs Up

Baseline System parameters with a DES

I'm designing a building on a college campus that has a DES. We opted to model option 1 for EAc1 (Building Stand-alone scenario). Our original baseline system was System 3, and we have district heating and cooling, so we shifted our baseline to 4-pipe CV 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.. The USGBC manual for treatment of District Thermal Energy says that any system parameters not specifically referenced in Table 3 (the baseline system revisions table) are modeled as specified in Appendix G.
Here lies the question: Appendix G doesn't specifically recognize a 4-pipe CV AHU system. My original system 3 was DX cooling and Fossil Fuel heat. There are several parameters that I need to model that aren't addressed by Appendix G's system 3 such as Hot Water design temps, HW Temp reset, Hot Water pump efficiencies, Chilled water design temps, Chilled water reset, and Chilled Water pump efficiencies.
Should I just use the values for other systems? It seems a little unfair because those other systems are more efficient that what System 3 would normally be. Any input would be appreciated.

1
1
0
Marcus Sheffer LEED Fellow, 7group Jul 31 2012 LEEDuser Expert 19813 Thumbs Up

Yes you use the values for the other systems that translates to a 4-pipe CV system (all of the hot water and chilled water baseline parameters). The chillers may be more efficient but the boilers are about the same efficiency in the baseline. I think the DES is just requiring an apples-to-apples comparison of HW/CW systems.

Post a Reply
0
0
Dominique Arrieta Gobbell Hays Partners, Inc.
Jul 06 2012
LEEDuser Member
100 Thumbs Up

Project Area

Hello, we have recently realized that our project gross area was one number, and the energy model done by our engineer did not include an atrium space in the middle of the project (project is on 3rd floor with this space in the middle) nor did he include shafts, etc. We are in the appeals phase and do not want to change the project gross area at this point. Does his model need to match our project area or can we explain this and not get denied? Seems like they have been very picky with this and we stand to make Platinum. Thanks.

1
3
0
Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jul 08 2012 LEEDuser Moderator

David, maybe I don't fully understand the question, but rather than reducing the gross floor areaGross floor area (based on ASHRAE definition) is the sum of the floor areas of the spaces within the building, including basements, mezzanine and intermediate‐floored tiers, and penthouses wi th headroom height of 7.5 ft (2.2 meters) or greater. Measurements m ust be taken from the exterior 39 faces of exterior walls OR from the centerline of walls separating buildings, OR (for LEED CI certifying spaces) from the centerline of walls separating spaces. Excludes non‐en closed (or non‐enclosable) roofed‐over areas such as exterior covered walkways, porches, terraces or steps, roof overhangs, and similar features. Excludes air shafts, pipe trenches, and chimneys. Excludes floor area dedicated to the parking and circulation of motor vehicles. ( Note that while excluded features may not be part of the gross floor area, and therefore technically not a part of the LEED project building, they may still be required to be a part of the overall LEED project and subject to MPRs, prerequisites, and credits.) to match the energy model, shouldn't you revise the energy model to include that space—assuming it's in your project boundary?

2
3
0
Dominique Arrieta Gobbell Hays Partners, Inc. Jul 09 2012 LEEDuser Member 100 Thumbs Up

We could do that, but we do not want to if we don't need to, seeing how we would have to appeal every point that was affected by the change in overall gross SF (a lot of points). My questions is, if we submit the energy calcs used with the lesser SF (no interior atrium space, also this space is on a different HVAC system than the project area) and leave the original gross SF unchanged, how do you think the reviewers would view this? Thanks for your help.

3
3
0
Daniel LeBlanc Senior Sustainability Manager, YR&G Jul 10 2012 LEEDuser Expert 578 Thumbs Up

David, in my experience the reviewers have no flexibility on this and from what you've described I don't see why they would make an exception here. It sounds like the interior atrium isn't within the project scope?

In any case the model should include these spaces and then separately account for energy use of the HVAC systems only for the spaces within the scope.

I agree with Tristan, adding those spaces back into the model is your best option. That way you can leave the gross SF in the other credits alone and have it be consistent across all credits.

Also - since you are in the appeals phase I would contact the LEED review team by e-mail with your proposed approach before your final submittal.

Post a Reply
0
0
Dana Villeneuve Sustainable Building Services Project Manager Architectural Energy Corporation
Jun 06 2012
Guest
102 Thumbs Up

Modeling of Retail Refrigeration System for LEED Retail CI

I'm working on a retail (grocery store) project which is pursuing LEED for Retail CI, and my question is, simply put: are we supposed to only model HVAC for EAc1.3 or can we include Refrigeration as well? Our store's refrigeration & HVAC systems are integrated together through a water loop pump and fluid cooler that serve both systems. Although the fluid cooler fan motor and the water loop pump motor have VFDs, the increase in energy consumption due to the motors overshadows the reduction in the cooling & heating savings of the HVAC system. The pumps are sized to handle heat rejection for both the refrigeration & HVAC systems, but the vast majority of the rejection of course comes from the refrigeration system, and we would therefore show little to no energy savings with these high-power motors if our model only illustrates HVAC components and not refrigeration components.

1
1
0
Daniel LeBlanc Senior Sustainability Manager, YR&G Jun 22 2012 LEEDuser Expert 578 Thumbs Up

Because the credit language asks for HVAC only, my gut reaction is that the reviewers will take issue with the inclusion of process loads. But it can't hurt to try to submit including the refrigeration as part of the HVAC design, especially if you've done the model already, and see if they accept your approach. Let us know what happens.

Post a Reply
0
0
Emma Eliasson Building Engineer Skanska Sweden AB
May 31 2012
LEEDuser Member
54 Thumbs Up

Option 2 - The Performance Rating Method

Hi,

LEED Reference Guide For Green Interior Design And Construction says in chapter EAc1.3 (# 6. Calculations) on p.168 that the standard has 2 energy comparison methods, both of which are appropriate for demonstrating energy cost savings to earn this credit. They are refering to the ECB method and the Performance rating method.

As I understand this are two dofferent methods. In my case I want to use the BPRM since I've already done this calulation for the CS-certification. But when I am about to fill in the form on LEED Online I can only see options for how to report the ECB-method. They want me to provide the ASHRAE Interactive ECB Compliance Report. I don't understand how to do the report when not using the ECB-method, but BPRM.

Can anyone help me to clarify this?

Thanks!
/Emma

Start a new LEED comment thread

Welcome !
May 20 2013
Type the characters you see in this picture. (verify using audio)
Type the characters you see in the picture above; if you can't read them, submit the form and a new image will be generated. Not case sensitive.

Copyright 2013 – BuildingGreen, Inc.