EFFECTS OF NOCTURNAL VENTILATION AND RADIANT COOLING/ HEATING FLOORS ON INDOOR AIR TEMPERATURES IN AN OFFICE BUILDING IN HOT ARID REGION

The effects of nocturnal ventilation and radiant cooling/heating floors on indoor air temperatures in an office building in hot arid region are evaluated. Climatic and indoor temperatures are measured and compared against predicted ones using TRNSYS®, obtaining a 7% difference. A parametric study was conducted that varied floor temperatures to simulate radiant floor heating on the coolest day and nocturnal ventilation or/and radiant floor cooling on the hottest day in 2009. Results indicated that, during the winter, radiant floor heating increased the indoor air temperatures from 13.5oC to 19.6oC. During the summer, the indoor air temperature decreased from 32.1oC to 27.4oC at midnight, with a nocturnal ventilation of 5 ACH. Combining ventilation and radiant floor cooling decreased the indoor air temperatures to 26.9oC (0.5oC lower). As a result, the effect of nighttime ventilation was significant on indoor temperatures in the building; however, the effect of radiant floor cooling was almost negligible.