Nonzero flow rate even all openings are closed

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Nonzero flow rate even all openings are closed

Postby gregorkecskes » Thu Jan 26, 2017 7:14 am

Hi everybody,

I was calculated the attached model sub-hourly with 30 timesteps for 1 day(15th Feb). In order to regulate the CO2 level in the office, EMS-controlled ventilation flaps(doors in this model) open when the CO2 level raises above 1200ppm and close when falls below 1000ppm. Hence, the doors open/close 8 times during the day, as seen from the flow rates on the attached picture bottom-left and also from the temperature curve top-right. None of these ventilations occur at full hour. Therefore my expectation is, that after importing these simulation results for the CFD calculation, the flow rates at any full hour will be zero. But this is not the case. For 12:00 for example I get 243 l/s (see picture bottom-right).

1, Why do I get nonzero flow rate when all the doors are closed at this timepoint ?

2, My second question: I would like to run a CFD calculation at the end of the ventilation event in order to see, how cold is the the office at the end of the ventilation event. The ventilation occurs for example from 10:40 to 10:45(based on simulation results). How can I run a CFD calculation at 10:45 ?

3, Finally, what "Average zone air temperature" means exactly ? Is it the temperature at the moment of the CFD calculation, or is this calculated as a mean of the last hour before the CFD calculation ? Is it calculated by DesignBuilder or it is from E+ ?

Thank you
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