Results Summary

This results summary section focuses only on the cases with natural ventilation. We only compare the cases with natural ventilation since in the mechanically ventilated cases a comparison (between mixing and displacement) is already done in each case. Even with this restriction it is still a limited comparison since some of the cases consider wind effects (CV), while others are not fully naturally cooled (the HYB cases use mechanically "powered" radiative cooling).

In each city we focus on two indicators of cooling system performance: the number of hours where the comfort temperature is above 27ºC and, for the cases with displacement ventilation, the number of hours where airflow is stratified.

The results of this comparison are similar in the three cities:

Comparing the natural displacement (DV) with the cross ventilation (CV) cases shows that cross ventilation is superior since it leads to a smaller number of overheating hours, as result of higher airflow rate. Generally larger airflow rates result in CV, when compared with DV.

In the case of the CV cases temperatures in the recirculation are generally higher than in the jet region, a direct consequence of the confinement effects that occur in the recirculations.

The advantage of the chilled floor is clear with a largely reduced number of overheating hours. The combination of this system with natural DV can be a suitable cooling solution in all three cities. Addition of the solar chimney is an effective way of increasing the number of hours with stratified flow, resulting in lower indoor temperatures.

Case Name	Airflow	Flow Pattern	Cooling Source
NAT CV	Natural	Cross-Vent.	Natural
NAT DV	Natural	Displacement-Vent.	Natural
HYB DV	Natural	Displacement-Vent.	Natural + Chilled Floor
HYB DV SC	Natural	Displacement-Vent.	Natural + Chilled Floor
MEC	Mechanical	Mixing	Cooled air