Hi
Our situation is the following: the outdoor ventilation rates in the proposed building are higher than required by ASHRAE 62.1. Therefore, the baseline model will have lower outdoor ventilation rates at design conditions than the proposed model. So far, we have applied the specific values directly from ASHRAE 62.1.
I have two questions:
1. For the Minimal Air Quality Credit, the proposed building has a Distribution Effectiveness of 80 %, so the total required minimal l/s in the proposed will be higher than these specific values (factor 1/0.8). Should we apply the same factor in the baseline model?
2. Due to the economizer, the actual outdoor air flow rate to a zone can be much higher than the value sized for air quality. The allowed fan power depends on the "pressure drop adjustement A", which in turn depends on, amongs others, the flow rate through the heat recovery device, i.e. the total outdoor air flow. Is it correct to use the actual total outdoor air flow from the model for this calculation?
Thank you!
Sarah
Tyler Thumma
7GroupLEEDuser Expert
60 thumbs up
April 15, 2020 - 1:13 pm
1. The Baseline outdoor airflows should be the ASHRAE 62.1 minimum values as calculated for the Proposed design, so they would include any corrections such as zone air distribution effectiveness.
2. You should only apply the minimum outdoor airflow, not the economizer airflow, to the pressure drop adjustments that are applicable to outdoor air only.