Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
In OpenStudio, one can only define/assign DSOA at the space level, but all (?) OA calculations are made at the zone level. As far as I have learned, when a zone has several spaces, and there are different DSOA for each of these spaces, then EnergyPlus randomly picks one of these DSOA to proceed with. The pick can and does differ from run to run, so, that is why I got random results from run to run. I was able to address this by calculating the average DSOA for all spaces of a zone, then assign this average DSOA to each of these spaces. That way, whatever EnergyPlus's pick-of-the-run may be, it'll always be the same DSOA, and at the zone level, the average DSOA should be all that matters anyway. Then I use the same DSOA for proposed and baseline, and my sizing and 8,760 h OA numbers indeed match.
