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

the experiments. The variation at the column between the ground floor and first floor on thesouth side resulted from to two main factors; the addition of a railing at the first floor level andsome amount of heat transfer between the ground floor and the first floor.On the north half of the first floor, air exited at both the lower and upper windows for all of thewind speeds used in the wind-buoyancy cases. At the column, a distinct pattern betweenentering air velocities above 3 m/s, between 1 and 3 m/s and below 1 m/s was found (Figure 76).At the higher wind speeds, the temperatures at the column had less variation from floor toceiling; however, for the mid-range of wind velocities the temperature measured near the ceilingwas distinctly warmer than that of the lower measurement locations. At the mid-range of windspeeds, the warm air from the atrium entered the north half of the first floor, was further heatedby the interior loads, and then some of the air exited back into the atrium. At the mid-way pointbetween the atrium and the north façade, the air either moved toward the windows at the northfaçade and exited, or flowed toward the atrium and exited at the ceiling level of the first floornorth. At the lowest wind velocities, the cooler air from the atrium entered into the first floornorth zone and then was heated due to the interior loads and exited back into the atrium, as withthe mid-range air velocities. However, since there was less airflow with the lower wind speeds,the air reached higher temperatures. In the heated zone of the north half of the first floor adistinct temperature pattern arose with wind velocities less than 4 m/s (Figure 77). There wassome amount of heat loss through the floor of this zone, though a layer of insulation board andadditional R-13 batt-insulation was installed. The temperature of the air increases due to theheaters and rises toward the ceiling. The warm air that exited back into the atrium at ceilinglevel was seen in the temperature measurements from the heated zone.Figure 69. Temperature Distribution for Combined Wind-Buoyancy Driven Flow at 0.5 m/sIn the second floor, the temperature distribution varied noticeably with the inlet wind speeds atthe column (Figure 78). At higher wind speeds, 4-5 m/s, the temperature was uniform from floorto ceiling. However, at velocities less than 4 m/s, the temperature close to the ceiling roseconsiderably. For the lower two measurement locations at wind speeds at or below 1.5 m/s, the143