Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
I believe the I/O reference is referring to a situation where a large space is divided up artificially into more than two fictitious subzones to try to capture stratification and circulation, not a situation in which there are two zones connected by a real opening. Dividing up a large space like that is something that many people have tried but few have been successful at. Note that the I/O ref says "within a thermal zone" in the first sentence of your quote.
