Net ZEB Case Studies - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 436

Fig. 7.62 (a) Physical enclosure: control volume of the occupied space
(surrounded with dashed-dotted line) and the typical cross-section of the
modeled section (thick dashed line), and (b) radiosity enclosure: boundary
for radiosity calculation (CV: convection; CND: conduction; IR: infrared
radiation)
Interzonal air convection correlation (Barakat, 1987)
(7.7)
where is the effective height of the zone (2.8 m, from the top of
workplane partitions toceiling). Itisalsousedasthecharacteristic heightin
the calculation of the Grashof number . and are the air temperatures
of the adjacent two zones. is the air conductivity. is the Prandtl
number of air (0.71). is the area of an imaginary opening between two
thermal zones. To account for the fact that the correlation just presented is
derived for interzonal convection through an opening between two thermal
zones, the value of is similar to that of a door (0.8 m × 2.05 m).
Natural ventilation. The outdoor air passing through the typical section is
able to mix well with a representative room air temperature, , at 5 air
changes per hour (ACH). At 5 ACH, the air velocity of indoor cross-airflow
will be about 0.025 m/s across the 18.3 m depth of the building. If the