Shade plays an important role in designing pedestrian-friendly outdoor spaces in desert cities. To improve thermal comfort through shading at a pedestrian mall, Arizona State University set up three, 10-m high photovoltaic canopy structures on its Tempe campus next to the Memorial Union (MU). The goal of this research is to quantify the impact of the installed photovoltaic canopies on microclimate and thermal comfort at the mall, using field observations and surveys. Our main objectives are threefold: (1) assess outdoor thermal comfort under photovoltaic canopies and in unshaded locations in a desert urban environment for different seasons and times of day; (2) investigate the relationship between measured and perceived comfort; (3) explore the determinants of thermal sensation, including non-climatic factors.

We installed six stationary, shielded temperature and humidity sensors underneath ASU’s photovoltaic canopies next to the MU and in nearby sun-exposed and tree-shaded locations, logging at a frequency interval of 5 minutes for a full year. Additional transect measurements were conducted hourly from 7:00 AM to 10:00 PM during a typical day in each season under clear and calm weather. During the transect observations, 1284 people were surveyed in the shade and sun close to the stationary sensors about their thermal comfort, perception, preference, recent sun exposure, activity, and adaptation level. This study will give insight into the relative importance of climatic and non-climatic factors that drive thermal comfort and highlights the importance of shade for the design of more walkable outdoor spaces in desert cities.