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

12:00 AM1:00 AM2:00 AM3:00 AM4:00 AM5:00 AM6:00 AM7:00 AM8:00 AM9:00 AM10:00 AM11:00 AM12:00 PM1:00 PM2:00 PM3:00 PM4:00 PM5:00 PM6:00 PM7:00 PM8:00 PM9:00 PM10:00 PM11:00 PMTemperature ( C)40353025201510Second Floor AverageGround Floor AverageFirst Floor North AverageFirst Floor South AverageOutside Air TemperatureFigure 19. Internal Temperatures from Extreme Heat Summer Day: Summer 2003Additionally, differences in temperature between the northern and southern halves of thebuilding were observed. During the summer months, the maximum temperature differencebetween the north and south floors was 4ºC; while during the winter months the difference wasas much as 8ºC. The maximum temperature difference for the summer period occurred duringthe nighttime hours, while the temperatures were similar for the north and south sides during thedaytime hours. The south side of the building tends to remain warmer than the north side due tosolar gains and thermal mass; it takes longer for the thermal mass to cool on the south side, sinceit is exposed to direct sunlight for more of the day than is the north side. This variation fromnorth to south was present and more appreciable during the winter months, with the temperaturedifference between the north and south halves remaining relatively consistent throughout theday. The solar gains had a significant impact on the south half, particularly when the sun waslower in the horizon and the solar shading devices attached to the façade were less effective. Thethermal mass retained the heat both from the solar gain and internal gains, and remained warmerduring the wintertime. During the summer months, the windows were also open, allowing moreair to flow through the building, causing a more even temperature throughout the building. Thesouth half remained somewhat warmer during the summer nighttime hours when the thermalmass released the heat stored from both internal loads and solar gain during the daytime hours.The variation from north to south for a sample period of time (late July through early August) isshown in Figure 21 and for a sample cold period (late October through beginning of November)in Figure 20.59