Hi All
At risk of looking foolish has anyone succesfully presented an AHU serving a single zone when all those zones are identical? The specific project is a shopping mall where there are AHUs providing fresh air only to shops, each shop is in theory treated the same way and so whether partitons exist or not it would be the same occupancy throughout. Could one argue that is a large single zone the calculaiton does not ensure that air is evenly distributed and so is there any difference?
In reality the air is not perfectly distributed to a few shops and so does not meet the requirements of the credit. Of course the right thing to do is to rebalance but the system is accessed through tenant areas and ceilings that are not accesible in places and so the Client is keen to pursue whether we can consider the shops as a single zone.
All thoughts much appreciated.
Many thanks
Rick
Ben Stanley
Senior Sustainability ManagerWSP - Built Ecology
LEEDuser Expert
250 thumbs up
March 8, 2017 - 6:18 pm
Hi Rick,
I think that it's possible that you could approach the calculation as a single zone system. Here's the definition from the ASHRAE 62.1 standard for a ventilation zone. If there's a single ventilation zone, it's a single zone system for the calculations.
ventilation zone: any indoor area that requires ventilation and
consists of one or more occupiable spaces with similar occupancy
category (see Table 6-1), occupant density, zone air
distribution effectiveness (see Section 6.2.2.2), and zone
primary airflow (see Section 6.2.5.1) per unit area.
Note: A ventilation zone is not necessarily an independent
thermal control zone; however, spaces that can be
combined for load calculation purposes can often be combined
into a single zone for ventilation calculations purposes.