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Hi all COMSOLers,

I'm building a time dependent model of passive heating wall called composite Trombe wall in COMSOL 5.1 with heat transfer and laminar flow modules. The geometry and model set up files are attached here, along with a flash gif. file to show how the air flows in the system.

To avoid over-heating in the summer and air reverse-flow in the winter, I want to control both the upper and lower vents' opening. As soon as there is a reverse flow for winter (warm air leaves room), or indoor temperature rising above 22 degree in summer, those vents will be closed.

I tried using these methods or tricks so far:
1, "phase change" function, to make the solid vent "vaporized" into air;
2, "deformed geometry" to downsize the vents to nothing;
3,"step" function to control the material in the vents domain to change from solid materiel to air;
4, or just cut the simulation into several pieces for vents on and off and on and off, which causes a lot of issues with initializing each model in order to match the results from the model of the time period before it.

Neither of them seems to work well for me, especially after I added "volume force" in fluid domains to create natural convection.

Is there anyway, for example, to use "events" function, or any other way, to make the vents show up and disappear during the simulation and also re-mesh the changed domains?

Thanks very much for any kind of help. Stuck in this issue for two weeks...Thanks a lot!

Jie