[Trace-users] Load Calcs vs Energy Model for LEED

[Caballero, Catalina]

Hello experts,

We recently received comments back from LEED  and one of the comments says the following:

It appears the equipment capacities (fan volume, fan power, cooling capacity, etc.) for the HVAC systems in the Proposed model
are inconsistent with the equipment capacities in the actual design when comparing the LEED Energy Performance Summary Report
to the mechanical schedules provided for PIf4: Schedule and Overview Documents
G3.1.10 in the Proposed building column requires that the Proposed model reflect all HVAC systems at actual equipment capacities
and efficiencies. The HVAC equipment capacities cannot be autosized in the Proposed model. Revise the Proposed model to reflect
all HVAC systems at actual equipment capacities. In addition, update Table 1.4.7B, and provide a revised LEED Energy Performance
Summary Report and the System Enterd Values reports for the Proposed model reflecting the changes. Further, if the equipment
capacities and efficiencies are based on updated mechanical schedules and/or HVAC submittal sheets, provide the updated
mechanical schedules and/or HVAC submittal sheets.

The only question that I have is why would they require for the airflows, to be exactly the same, to the original load calculations when the load calculations looks for the worst case scenario (using ashrae basic envelope, lighting, values), while the energy model looks for the most energy efficient model (actual installed envelope, occupancy, etc). It make sense that they are looking for something similar but it’s definitely not going to match the capacities and or airflows, (load calcs tend to be oversized).

I would greatly appreciate your opinion.

Thanks.

Catalina Caballero.  AIA. Assoc., LEED GA.
Sustainability Coordinator

Johnson, Avedano, Lopez, Rodriguez & Walewski Engineering Group, Inc.
Engineering for High Performance Buildings.
MEPF - BIM - LEED - Cx

2510 NW 97 Ave, Ste 220, Miami, FL 33172.
P: 305.594.0660  Ext: 217 Ӏ F: 305.594.0907
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