Forum discussion

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

HVAC Appropriate Zoning and Control

Dear all, We are working on a Commercial Interiors project, where there is a base building chiller (not in our scope), and we have a F&C system. We are trying to achieve this credit with the Appropriate zoning and controls option, the form asks to select all that apply, the third option states: "there is no separate method for modulating the HVAC system in response to space demand" , which I suppose would be our case, since we do not have occupant sensors in private offices, nor CO2 sensors. The new forms do not allow us to verify compliance, but I'm wondering if we will be able to achieve the credit if this is the case. I hope this makes sense, thanks!

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Sat, 08/06/2016 - 18:09

It sounds like you will not be able to get this credit. There are two LEED Interpretations which have added additional requirements, particularly requiring modulation of air flow to meeting rooms in response to space demand. You'll also need occupancy sensors in private offices to reset HVAC to default levels, but you don't need to modulate the airflow in offices. Check the LI database for additional details.

Wed, 08/10/2016 - 16:14

Thank you Michael! Just to make sure we get it right, we would not need to install CO2 sensors? Only the occupancy sensors?

Thu, 08/11/2016 - 06:21

Whether you use CO2 sensors will depend on your system. The credit and LI do not require CO2 sensors, they require the system to modulate airflow when the room is not occupied. In most VAV installations, this would be accomplished with CO2 sensors, but in a CAV system you can use occupancy sensors to achieve the credit requirements.

Wed, 10/26/2016 - 07:28

Hello We have a similar case in a project. Chilled water is delivered by district cooling plant. The HVAC system in the fit out is limited to FCUs. Each zone has a seperate FCU. We plan to integrate occupancy sensors with thermostat. The FCUs are high efficient inverter motor driven We opt to Puruse the credit with Option 1: Prescriptive path, Efficiency requirements are FCUs are not covered in Section 2.9 of CPG. How do we demonstrate compliance of "Section 2.9: Mechanical Equipment Efficiency requirements – Meet or exceed the minimum requirements for efficiency for listed equipment in the CPG"

Wed, 10/26/2016 - 14:48

I think that if your equipment is not covered you comply by default. Anyone else have contrary experience?

Wed, 10/26/2016 - 17:14

There's another LI applicable to Option 1 that requires the base building systems serving the space to comply with the CPG. That would apply to your ventilation system as well as the chilled water (and heating if applicable.) To be honest, I have no idea how the CPG would apply to the district cooling system. As Marcus points out - if the CPG does not cover the equipment in the district cooling system then you should comply by default. That said, I know that LEED has guidance on how to treat district systems which I've never researched - that guidance may also be relevant.

Tue, 11/29/2016 - 05:56

Thanks for your inputs. Will keep you posted on the updates when we submit the application

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