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I’m running a simple test case with two identical zones (Office and Reception), empty and unconditioned, to reproduce a behavior I can’t explain that I’ve noticed in my project model.

I’m comparing three runs:

• 00-noairwall: Zones share a generic interior wall.
• 01-airwall-noflow: Zones separated by an AirBoundary, but no air mixing defined.
• 02-airwall: Same AirBoundary, plus two ZoneMixing objects (Office → Reception and Reception → Office) at an equal constant flow rate of 3 m³/s (0.1 m/s over the wall area).

• The results of 00-noairwall make sense: Reception heats up in the morning (east-facing windows), and Office heats up later (west‑facing windows).
• In 01-airwall-noflow, the two zone temperature curves converge toward each other, roughly averaging the two spaces.
• In 02-airwall, after adding the air mixing, both spaces' temperatures flatten and no longer reach the nighttime lows or daytime highs, with also a lag of a few hours. I probably would expect just a faster averaging between the zones, not such a dampening of their peaks.

Note that for mixing I also tried setting the "Air Exchange Method = SimpleMixing" in the "Construction:AirBoundary", instead of the ZoneMixing objects, but it gave identical results.

Am I missing any basic concepts of how interzone air mixing works?

I’m running a simple test case with two identical zones (Office and Reception), empty and unconditioned, to reproduce a behavior I can’t explain that I’ve noticed in my project model.

I’m comparing three runs:

• 00-noairwall: Zones share a generic interior wall.
• 01-airwall-noflow: Zones separated by an AirBoundary, but no air mixing defined.
• 02-airwall: Same AirBoundary, plus two ZoneMixing objects (Office → Reception and Reception → Office) at an equal constant flow rate of 3 m³/s (0.1 m/s over the wall area).

• The results of 00-noairwall make sense: Reception heats up in the morning (east-facing windows), and Office heats up later (west‑facing windows).
• In 01-airwall-noflow, the two zone temperature curves converge toward each other, roughly averaging the two spaces.
• In 02-airwall, after adding the air mixing, both spaces' temperatures flatten and no longer reach the nighttime lows or daytime highs, with also a lag of a few hours. I probably would expect just a faster averaging between the zones, not such a dampening of their peaks.

Note that for mixing I also tried setting the "Air Exchange Method = SimpleMixing" in the "Construction:AirBoundary", instead of the ZoneMixing objects, but it gave identical results.

Am I missing any basic concepts of how interzone air mixing works?

I’m running a simple test case with two identical zones (Office and Reception), empty and unconditioned, to reproduce a behavior I can’t explain that I’ve noticed in my project model.

I’m comparing three runs:

• 00-noairwall: Zones share a generic interior wall.
• 01-airwall-noflow: Zones separated by an AirBoundary, but no air mixing defined.
• 02-airwall: Same AirBoundary, plus two ZoneMixing objects (Office → Reception and Reception → Office) at an equal constant flow rate of 3 m³/s (0.1 m/s over the wall area).

• The results of 00-noairwall make sense: Reception heats up in the morning (east-facing windows), and Office heats up later (west‑facing windows).
• In 01-airwall-noflow, the two zone temperature curves converge toward each other, roughly averaging the two spaces.
• In 02-airwall, after adding the air mixing, both spaces' temperatures flatten and no longer reach the nighttime lows or daytime highs, with also a lag of a few hours. I probably would expect just a faster averaging between the zones, not such a dampening of their peaks.

Note that for mixing I also tried setting the "Air Exchange Method = SimpleMixing" in the "Construction:AirBoundary", instead of the ZoneMixing objects, but it gave identical results.

Am I missing any basic concepts of how interzone air mixing works?