Minimum IAQ Performance Calculator - Multiple Zone and 100% OA

The zone discharge airflow is the design supply airflow. The zone primary airflow is the amount that comes from the AHU or central system. The secondary re-circulation has to do with local re-circulation within the space.

The Evz will be calculated by the spreadsheet. You should definitely study the ASHRAE 62-1 Standard.

Hello Andrew, Thanks for initial information you mentioned.

I just have to expand some queries related to this post. My current project has dedicated AHUs per tenancy floors and OA is distributed to each AHU from a main unit at roofdeck. AHU is supplying the mixed air into interior spaces through VAVs, with single/primary air recirculation only (no secondary/local recirculation). We are using multiple zone mode. Queries:

1.0 With this condition, is it proper to have equal zone discharge (Vdz) and zone primary air (Vpz) flows per analyzed space?

2.0 Is the Total Zone Primary Air flow (Sum of Vpz) equal to the supply air capacity of AHU and to the System primary airflow (Vps) in the calculator spreadsheet?

3.0 Using the latest VRP calculator, what should be the resulting Occupant Diversity (D) range acceptable to reviewers. Is the System Population (Ps) should be equal to FTE declared in other credits?

4.0 What is exactly they are referring as the worst case scenario with lowest supply air flow? Below is a comment from LEED reviewer. Appreciate your help and advise.

"It appears that the Ventilation Rate Procedure (VRP) calculations may not have been performed for the worst-case conditions, as it is not clear if the cooling condition calculations analyze the lowest supply airflow rate that can reasonably be expected to occur when each space is fully occupied. This lowest supply flow condition when occupied is anticipated to be the worst-case ventilation condition. For interior zones in cooling mode, this flowrate is expected to be somewhere in between the minimum flow setting and the design cooling flowrate.

Provide revised calculations that address the worst-case condition or provide information to justify the parameters used."

Hi Eric Bautista,

How u have addressed the above comment of the reviewer? 
We also have recently received the same comment from the reviewer. I have also used in calculator is already based on equipment schedule (design flow rate) and no idea how to find the lowest supply airflow rate.

Thanks

Devendra C.