Heat transfer coefficients

The passive cooling techniques such as night time cross ventilation is potentially an interesting strategy to provide substantial cooling energy savings in warm climates. The efficiency of the night cooling ventilation is determined by three main factors: the external air flow rate in the room, the flow pattern and the thermal mass distribution. Most of the software used to simulate building thermal performance assumes natural convection in the enclosure; therefore the convective heat transfer coefficients for internal room surfaces are underestimated.