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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.
For example, if the project scope includes only 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 connected to a base building ventilation system, then only the VAV boxes would be included. If there are no HVAC components within the project scope, the project is not eligible for the credit....
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38 Comments
Computer Room Grade Air Conditioning Units
When utilizing the Core Performance Guide EER ratings I have not been able to find a computer room grade unit that can exceed these EER values. Is this a problem on a lot of projects or can the units be excluded from the EER criteria because they are of a critical nature?
David Posada replied Sustainability Manager, GBD Architects Mar 25 2010
We're wondering the same thing about a rack mounted cooling unit for a server room that our client's IT department has specified. The rack-mounted units direct cooling exactly where it is needed instead of cooling the whole room indirectly, so we believe it is the more efficient approach, but we can't find any units that meet the prescriptive requirements of the Core Performance Guide.
The schedule is tight enough that waiting for 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 may take too long to resolve this, and it seems crazy to have to pursue the energy modeling option for a very large TI when this is the only component that doesn't fit the perscriptive path.
Does anyone else have any thoughts or experience with this?
CI 2009 EAc1.3 Optimize Energy Performance - HVAC
Zoning and Controls
Please confirm what is meant by "active controls" for private offices and special occupancies. Does that need to be a seperate 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 for every single occupancy office or can we meeting the intent of this with some other technology?
Erik Dyrr replied Director, Sustainable Buildings and Operations, KEMA Feb 10 2010
A v2.0 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 and v3 ref guide state..."The system must be capable of modulating AHUs and zone minimum supply volume below 0.30 cfm/sf of supply volume for standard 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. terminals, or below 22.5% of the peak design flow rate for fan-powered VAV boxes. For spaces where the min. outdoor air flow exceeds the min supply volumes specified here, use occupant sensor or DCV to achieve these min supply volumes."
I have taken this to mean all offices must have a vav or be single zone. However, maybe if you have sensors in each office and all offices within a zone report unoccupied the VAV is turned down. I have not submitted in this fashion, but it may work.
Anyone else try this?
Must have VAV system for Option 1?
When we look into the LEED Reference Guide for Option 1, it seems to require 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 which we do not have (see pg. 168). We can show compliance with ASHRAE 90.1 Mandatory requirements but not the modulating air handling units and not the fan static pressure reset, both of which are features inherent with a VAV system. Is there something we're missing that would still allow us to use the Core Performance Guide efficiency requirements and not have to go to the effort and expense of an energy model?
Erik Dyrr replied Director, Sustainable Buildings and Operations, KEMA Feb 10 2010
Can you inform us of the type of air handling you do have?
The modulating aspect would still apply. If single zone units, then it is an on/off scenario.
Dave Intner replied Firmitas Architecture & Planning Feb 17 2010
Thanks for your reply, Erik.
The project is utilizing constant volume packaged gas/electric units, however, the units are specified with a variable frequency drive (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.) which will allow them to maintain a constant airflow to the space as the filters load up (and their static pressure drop increases). The higher filtration for this project is a result of the space being an OSHPD 3 occupancy.
By an ‘on-off’ scenario, are you talking about the fan shutting off when there is no demand? Due to the code's ventilation requirements, the fan will run when the space is occupied, continuously.
Erik Dyrr replied Director, Sustainable Buildings and Operations, KEMA Feb 17 2010
With a typical constant volume system I don't know how the project could meet the requirements of modulating the airflow. The only option I can think of is to modify the system with zone dampers controlled by occupancy or CO2Carbon dioxide sensors. But this is not likely a feasible option.
Dave Intner replied Firmitas Architecture & Planning Feb 18 2010
Thanks Erik. It seems we're in a situation where code ventilation requirements are trumping opportunities for efficiency.
What if no fan/pump motors are greater than or equal to 5 hp?
Option 1 of this credit states that all motors 5 hp and greater must have VFDs that decrease fan power to 30%. If none of the installed fan motors are 5 hp or greater, can this credit be achieved? Playing with the LEED credit form shows that you must enter something into this section, even if it's not applicable. Additionally, you must enter a percentage 30% or less for 5 points to be documented on the form.
Erik Dyrr replied Director, Sustainable Buildings and Operations, KEMA Mar 23 2010
This credit can still be achieved with motors that are 5 hp or less. In your specific case I would choose the alternative compliance check box at the bottom of the form and type a short narrative into the corresponding box, stating that all motors are less than 5 hp and do not require 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.'s. You might also choose to include an equipment schedule with the fan powers listed.
Applicability of CPG sections 2.9 and 3.10
Like Heather's question above, what if the equipment to be installed is less than 5 hp AND doesn't fall under the HVAC equipment categories listed in section 2.9 of the CPG, such as Variable Refrigerant Flow systems? The closest thing might be DX split systems, but this is not an apples-to-apples comparison since this equipment efficiency is regulated by ARI 340/360, yet VRF has no ARI standard, but is generally regarded to be more energy efficient. Can section 2.9 be deemed as not applicable in this case?
Also, what if the new HVAC systems are hydronic fan coils, less than 5 hp, served by an existing chiller and boiler outside the project scope? Can this credit still be achieved by just complying with section 1.4 of the CPG?
Erik Dyrr replied Director, Sustainable Buildings and Operations, KEMA Mar 23 2010
In answer to your first question, there does not seem to be a relevant 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, but your safest approach would be to not attempt a VRF system under the prescriptive approach. You can't deem a section of the CPG as not applicable, you have to meet it's requirements. If you can not do so, then the prescriptive approach can not be achieved by your project. In the previous question, it's an error with the LEED template functionality, less than 5 hp motors do not require 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.'s. Here, you're attempting to use a system type not supported by the CPG.
In regards to your 2nd question, the CPG is very clear that if the motor is rated at less than 5 hp, it does not require a VFD. In this case, if it's served by an existing chiller, than the chiller is outside the project scope and does not need to fulfill the requirements of the CPG.
John Bauer replied Jun 13 2010
I am working on the project in China (1 floor fit-out) which has 1 Water Sourced Heat PumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. that (connected to the condenser water riser) for the server room and the rest of the AC is Chilled Water Fan Coil Units (connected to the Chilled Water Riser). So based on that, the only item I need to consider for equipment efficiency under 2.9 is than only the heat pump since the FCU are not in table of the CPG (CEE) and the FCU are below the treshold for 3.10 - Correct ?
Paul Conrad replied Energy Engineer, CLEAResult Consulting Jun 21 2010
John,
I believe you still have to account for the chilled water system and it's accompanying FCU's in 2.9. If, however, the CPG does not appear to be applicable to your current system, then, as Erik says above, you can not use a prescriptive approach and must use a performance approach.
John Bauer replied Jun 21 2010
Thanks Paul: If I have Chiller and Pump outside and only 2 kW of fan power on the FCU what sense does it make to do a performance approach (compared with what system) - John
John Bauer replied Jun 21 2010
Paul: 1 more thing: The FCU are provided by the Landlord as part of the Core and Shell work. The only AC added is a Heat PumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. for Server Room that meets the CPG requirements - John
Paul Conrad replied Energy Engineer, CLEAResult Consulting Jun 23 2010
John,
I did a little more research, and it's a little nebulous as to what we're looking at here. As far as I can tell, you need to account for whatever energy you're using for space cooling. If it's a build out of only part of the building, you're obviously not going to use all the chilled water that the chiller is producing, however, you absolutely need to account for the FCU's that are in your space. They're the mechanical equipment serving your space.
If the FCU's meet the requirements of the CPG, then you're fine. If they don't or don't seem to apply, then you need to use an ASHRAE 90.1 Appendix G Performance approach, where you account for the entire building, but the only difference between the baseline and proposed building is the HVAC. Then you compare the Baseline HVAC energy use versus the Proposed.
John Bauer replied Jun 23 2010
The CPG refers to equipment that are either Split or Packaged Equipment (Fan Coils are not covered). Since the FCU, Envelope and Light Fixtures are by Landord how can I do Baseline vs Proposed ?
John Bauer replied Jun 23 2010
This is a Commecial Interior Job and we have only 1 Floor in a 50 Storey Building...............
Paul Conrad replied Energy Engineer, CLEAResult Consulting Jun 23 2010
John,
I just found some information that will ease your heart significantly. I just confirmed that you were right in your original assertion that only the Heat PumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. needs to be accounted for. The key idea is that the FCU's and Chiller are outside your scope of work.
Sorry for the confusion. If your heat pump meets the CPG, you should be fine on this credit.
John Bauer replied Jul 30 2010
Paul, thanks for easing my heart. We found a unit here in China that exceeds the ARI-ISO 13256-1 rating for CEE Water Cooled Tier 1 (14.0 EER) as there is no Tier 2 according to www.cce1.org 2009 Standards yet. So that should serve the CPG requirements and get us the 5 credits under EA 3.1 equipment efficiency.
John Bauer replied Jul 30 2010
www.cee1.org
Zoning and active controls- Can offices share controls?
We have recently been getting review comments back from the GBCI asking that "some form of active control is required for every individual office."
For our projects, every individual office has active controls. No office has been left out even if some offices within a zone share controls.
It looks like word "individual" has been added by the review team. The actual credit language states: "Private offices and specialty occupancies (conference rooms, kitchens, etc.) must have active controls capable of sensing space use and modulating HVAC system in response to space demand"
The CI reference guide also states on page 156, “These requirements have avoided establishing design guidelines as to when an area must be zoned separately… The project design team will need to evaluate the project particulars and provide reasonable justification for its zones and controls”.
Can anyone explain what might seem to be a contradiction between the reviewer responses and the Reference Guide?
Erik Dyrr replied Director, Sustainable Buildings and Operations, KEMA Apr 09 2010
I have always interperated it as each office or space must have individual controls. This has made it very difficult to achieve this point with any multi-zone system. I see your interpretation of the ref guide and agree that it could be read that way. And that interpretation is much more reasonable.
Typical 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. zones for private offices include about 3 standard size office per VAV box. If every office requires controllability, it is generally not reasonable or possible to do. If occupancy sensors could be used to reduce airflow when there is no occupancy in any of the 3 offices, this would allow many more projects to install this type of control and overall achieve more energy savings.
However, I don't have any answers for you. If you hear from USGBC on this, please forward the response.
Karen Joslin replied May 18 2010
In my experience the active controls are absolutely required in each space - this does mean separately from other spaces. There are some cases where a very small enclosed space next to and zoned with a larger space has been allowed based on the frequency and duration of the smaller space's use and how small it is. This is a case of many projects simply not being eligible for the credit.
Base line consideration
What should we consider as baseline if we are replacing some of the HVAC equipments?
Erik Dyrr replied Director, Sustainable Buildings and Operations, KEMA May 05 2010
If you are following Option 1, then the efficiency requirements of the new equipment are provided in the Core Performance Guide section 2.9. If your new equipment has a better efficiency than the values listed in the table, then it meets this part of the requirements. The design must also meet the requirements of section 1.4: Mechanical System Design and 3.10: Variable Speed Control (if applicable).
If you are following Option 2, then the baseline requirements are the minimum requirements of ASHRAE 90.1- 2007
HVAC system Modulation
Considering a multi-zoning office with separate constant volume systems and zone control on every solar exposure, private office & special occupancies; can modulation of HVAC system in response to space demand be controlled on chilled water side through 2-way modulating valves with a contant or Air supply modulation through 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 a must.
Adib Schreim
Erik Dyrr replied Director, Sustainable Buildings and Operations, KEMA May 05 2010
I'm not sure I understand the question, but I'll take a shot at answering. To my knowledge the fan system is what is required to modulate. So controlling the chilled water valve would not achieve this.
amy amster replied Jul 08 2010
Fluorotherm did a wonderful job, I am happy to recommend their products. Heat Exchangers replaced our old tank(s) heating system. We are saving money with the new products.
Clean room project
How can I model a clean room project where there is a lot of non process load in the HVAC. Can I assume HVAC as process load since it is not just for human comfort and is also for having the proper air changes per hour.
I have heard that CI v.2009 now requires documented two project experience in energy modeling, is that correct??
Paul Conrad replied Energy Engineer, CLEAResult Consulting Jul 30 2010
Xavi,
Modeling projects involving clean rooms can get ugly in a hurry. My advice would be to model two separate HVAC systems in the proposed design. One that solely serves the requirements of the clean room and the other serving the rest of the space, both of which use actual design values. I'd then put the exact same clean room system in the baseline design and claim no margin. The 2nd HVAC system serving the rest of the building, I'd make equal to the requirements for your building baseline according to ASHRAE 90.1-2007 Appendix G.
I don't have my Reference guide with me today, so I'm not sure on the two documented project rule as far as CI is concerned. I know it's true for NC.
Xavi B replied Jul 30 2010
Thanks a lot, it makes sense.
How do you document your energy modeling experience. I've been doing this for 10 years but outside US, and haven't done anyone for LEED yet, so I'm a little bit confused on how to demonstrate experience.
Paul Conrad replied Energy Engineer, CLEAResult Consulting Jul 30 2010
Don't quote me on this Xavi, but I believe it's just a narrative detailing your experience. I'll try and see if I can find out more of what's required.
Xavi B replied Jul 30 2010
I'll appreciate it since I have a LEED project to quote on, and I don't know if I will be allowed to do it.
Non-occupied Spaces
I'm working on a TI project where the tenant occupies 2 floors of an 8-story office building. I have an overhead 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 and I am working on the ductwork distribution to ensure the project meets the zoning and controls requirements. There are several interior spaces, with floor-to-ceiling walls, that are not regularly occupied. For example, IT closets, restrooms, storage rooms, etc.. Is there any LEED requirement for zoning these spaces separately? My thought is that these not regularly occupied and serving them from a VAV box dedicated to another space is appropriate. Does anyone have any experience with zoning in regards to this credit?
Paul Conrad replied Energy Engineer, CLEAResult Consulting Aug 25 2010
James,
For a TI project, the key to always remember is that you only have to account for the aspects of the building that are within your scope of work. If 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. equipment on the roof is currently in place, you don't need to account for it. If you're installing VAV boxes, you need to account for those, but not the rest of the system.
To address your zoning specific question, you only are required to zone them separately if they're served by a stand alone HVAC system.
Paul
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