Characterization of Thermal Comfort in a Passively Cooled Building Located in a Hot-Arid Climate

This article compares the thermal performance and comfort levels produced by dry and wet roofponds monitored during the summer of 2011 in Las Vegas, NV.  The measured data shows that under typical summer conditions, a dry roofpond with a depth of 15.24 cm. installed over typical U.S. residential construction is able to keep the maximum indoor operative temperature approximately 5.1 C° below the maximum outdoor air temperature, with the minimum indoor operative temperature remaining approximately 1.8 C° above the minimum outdoor air temperature. A wet roofpond with the same depth and construction characteristics is able to improve the performance of the dry roofpond by lowering the maximum indoor operative temperature an additional 3.4 C° (for a total reduction of approximately 8.5 C°), while also maintaining the minimum indoor operative temperature approximately 2.2 C° below the minimum outdoor air temperature. While neither one of the roofponds achieved comfortable conditions 100% of the time during the harsh  summer conditions found in Las Vegas, NV, a wet roofpond applied to a better insulated one-storey house featuring ceiling fans might be able to reduce the uncomfortable period to a few hours per day during the hottest days of the summer season.