Methodology for the Evaluation of Natural Ventilation in ... - Cham

7.1 Buoyancy-Driven Ventilation ResultsThe results for the three buoyancy-driven ventilation experiments, single zone, two zone and fullmodel, are presented along with the comparisons to the numerical simulations.7.1.1 Single Heated Zone CaseThe simplified model with a single heated zone connected to the atrium was investigated usingonly the lower windows initially, and then using only the upper windows. This allowed viewingthe effect of window location on the flow patterns and resulting temperature distribution withinthe heated zone. The physical model was then created as a CFD simulation using PHOENICS.The single heated zone model was evaluated for temperature distribution, air flow rate throughthe model, and heat loss through the envelope. The temperature distribution was evaluated inboth the heated zone and within the atrium space. Additional temperature measurements wererecorded at the inlet and outlet conditions.The measured temperature data within the physical model provided insight into the influence ofwindow location on the internal temperature distribution. The data for the upper windows opencase and lower windows open case were compared using the situation with seven windows andthree stacks open for each case in Figure 45 through 47 below. The data recorded from thephysical model were non-dimensionalized and scaled for use in predicting the full buildingtemperatures. The full building temperatures and corresponding height within the space arepresented, using 20°C as the ambient conditions for the full building case. At the column,located at the edge of the heated zone where it connects to the atrium, the temperaturedistribution was similar for both the upper and lower window case (Figure 45). This was similarto the atrium temperature distribution, shown in Figure 47, where the location of inlet windowsdid not significantly affect the temperature stratification. The maximum temperature differencebetween the upper and lower window measurements for both the scaled column and atriummeasurements was 0.13°C.In the heated zone, the temperature patterns were somewhat different between the upper andlower window locations. When the upper windows were used, the temperature measurementclosest to the floor and ceiling were higher than for the lower window case at the mid-point ofthe heated zone, where the vertical temperature measurements were taken. For the lowerwindow experiments, the temperatures within the heated zone were very similar for the upperfour points, and then increased closer to the floor, which was located 3 cm above the heatedaluminum plate. The maximum temperature difference of 0.45°C occurred at a height of 1.1m(9.5cm as measured in the model) from the floor.119