We are working on a project where there are multiple AHU's in the single floor. Few AHU's have MERV-14 filtration and in built HRW. The rest of the AHU's only has MERV-8. This is an airport terminal. Baseline system is system-8 Variable air volume system. While considering base case - one system per floor, how to model the fan power? The factor 'A" accounting for the pressure drop based on the proposed case. Do we have to model One AHU per floor considering the static pressure from MERV-14 and Heat recovery wheels? Alternatively model 2 AHU's per floor for each type of AHU.
Please let me know. Thank you.
Tyler Thumma
7GroupLEEDuser Expert
60 thumbs up
July 15, 2021 - 1:23 pm
You model one AHU per floor, and only apply the airflow through the device to the pressure drop adjustment. Let's say 30% of the total design airflow for that floor includes MERV 14 filtration, you would multiple the 0.9 in. w.c pressure drop adjustment by 30% of the Baseline AHU airflow. Heat recovery pressure drop adjustments are only applicable if heat recovery is required for the Baseline system per the footnote to Table G3.1.2.9.