Infiltration
Infiltration is the unintended flow of air from the outdoor environment directly into a thermal zone. Infiltration is generally caused by the opening and closing of exterior doors, cracks around windows, and even in very small amounts through building elements.
The basic equation used by EnergyPlus™ to calculate infiltration is:
Infiltration = (Idesign)(Fschedule) [A + B| Tzone− Todb | + C WindSpeed + D Windspeed2]
Where
A = constant term coefficient
B = Temperature term coefficient
C= Velocity term coefficient
D = Velocity squared term coefficient
The default coefficients (A=1; B, C and D = 0) create a constant airflow infiltration.
These library members are applied to the building’s zones in the room properties screen. TRACE® 3D Plus has standard library members that include typical infiltration rates.
The infiltration library member details screen displays the fields that must be defined:
Name
Defines the name of the library member. Standard library members can’t be modified.
Airflow rate
Defines the infiltration rate that will be applied to a given zone. The rate can be defined as a rate per area of floor (cfm/sq. ft. floor), wall (cfm/sq. ft. wall), and air changes per hour or by the full design volume (cfm).
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Default Value: 0.6 ACH
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Typical Range: 0 to 1
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Min & Max: 0 to 1,000,000
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Units: cfm/ft2 floor, cfm/ft2 wall, cfm/ft2 surface, cfm, ACH ; (m3/s)/m2 floor, (m3/s)/m2 wall, (m3/s)/m2 surface, m3/s
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