Description

In this case the single zone office building will be cooled using natural displacement-ventilation. Ventilation openings are located in the North (high level outflow) and south façade (low level inflow). The windows are open during working hours.

Cooling Strategy

Outside air is used to remove heat from the building in a displacement-ventilation configuration.

EnergyPlus Models Used

Displacement-Ventilation model (UCSD Displacement Ventilation) COMIS (buoyancy driven airflow)

Simulation Results

Analysis

In order to avoid excessive complexity and improve clarity in this analysis wind effects were not considered.

The results clearly display the positive effects of vertical stratification. The natural displacement of internal gains into the upper mixed layer is clearly beneficial; the number of overheating hours is visibly decreased compared with the previous, CV, case, in spite of the much lower airflow rates. Since, on average, the internal temperature is lower than outside vertical stratification is maintained in the majority of the hours of operation.

However, the percentage of overheating hours in the high gains scenario is clearly excessive. In order to deal with this problem we introduce a mechanically cooled chilled floor in the following cased (therefore changing its label to HYB hybrid cooling).