RE: [EnergyPlus_Support] WindandStack and night ventilation always off

[Lixing Gu <gu@xxxxxxxxxxxx>]

The ZoneVentilation:WindandStackOpenArea object calculates ventilation rate
based on wind and stack. Since the input of Height Difference is zero
(default value is used if the input is blank), the wind driven ventilation
is calculated only. The wind drive ventilation rate is a function of wind
speed. It is possible that the wind speed is zero during a period between 23
and 7. Could you check the wind speed?

Hope this helps.

Lixing Gu 

-----Original Message-----
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of dani_lore1984
Sent: Thursday, June 16, 2011 6:44 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] WindandStack and night ventilation always off

Dear all,
I'm simulating my building for an university work and I'm trying to evaluate
daily summer ventilation with my windows open. I've used
WindandStackOpenArea object and it works well but, I don't understand why,
during night time from 23:00 to 7:00 I have no ventilation also with
schedule "Always on".

ZoneVentilation:WindandStackOpenArea,
    NATURAL_B_T_Sala,        !- Name
    B_T_PAN-Sala,            !- Zone Name
    1.9,                     !- Opening Area {m2}
    Always On,               !- Opening Area Fraction Schedule Name
    autocalculate,           !- Opening Effectiveness {dimensionless}
    150,                     !- Effective Angle {deg}
    ,                        !- Height Difference {m}
    autocalculate,           !- Discharge Coefficient for Opening
    -100,                    !- Minimum Indoor Temperature {C}
    ,                        !- Minimum Indoor Temperature Schedule Name
    100,                     !- Maximum Indoor Temperature {C}
    ,                        !- Maximum Indoor Temperature Schedule Name
    -100,                    !- Delta Temperature {deltaC}
    ,                        !- Delta Temperature Schedule Name
    -100,                    !- Minimum Outdoor Temperature {C}
    ,                        !- Minimum Outdoor Temperature Schedule Name
    100,                     !- Maximum Outdoor Temperature {C}
    ,                        !- Maximum Outdoor Temperature Schedule Name
    40;                      !- Maximum Wind Speed {m/s}

Here the situation in the worst summer day (ventilation = "Energia per
ventilazione naturale", blue colums):
http://img850.imageshack.us/img850/5955/ventm.png

How is it possible?
Thanks in advance
 



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