Thermal Comfort Assessment of the Proposed Green Roof for the College of Architecture and Landscape Architecture, Tucson, Arizona

Abstract

This master's report describes a method for thermal comfort assessment of green roofs in the urban environment of hot arid regions. The dual goal of this study is to not only emphasize green roof technology but also to promote outdoor living by demonstrating techniques that achieve thermally comfortable microclimate. Methods of investigation for this project started with an experiment, which included building a physical model of 4'x4'x4' with three different roof types; asphalt shingle, corrugated metal and saturated/dry green roof. This model was then used to record the four environmental variables that were used to help predict thermal comfort. These are: Surface Temperature, Dry bulb Temperature, Globe Temperature, and Relative Humidity. Average air velocity was used. The premise behind conducting this experiment was to validate the superior performance of green roof over other roof types in a hot arid surrounding. Additionally, the gathered data was used for comparison with results derived from OUTDOOR© a computer program for the assessment of outdoor thermal comfort conditions. The project applied to a proposed green roof top at the College of Architecture and Landscape Architecture in Tucson, Arizona. Distinct locations were chosen on the proposed roof for performing thermal comfort analysis. Fish eye lens photography slogn with other data acquisition systems were used to simulate the conditions at the determined locations using the OUTDOOR© program. Results derived from this simulation were found to be conforming to original results from the experiment. The earlier evaluation brought forth the highly uncomfortable thermal conditions existing on the roof. Design strategies were suggested to counteract the existing situation and to bring temperatures within comfort zone. The final results indicate that simple but informed modifications to design can help provide desired outdoor thermal comfort levels even during the extreme climate found in the months of June and December.