Comfy’Pack : Assessing urban microclimate conditions and outdoor thermal comfort at pedestrian scale

How does urban space shape small-scale pedestrian thermal environments in the context of intense heat? To answer this research question, various mobile sensing techniques are proposed recently. However, the assessment of thermal environments at pedestrian level is complex because of physical urban heterogeneity, highly variable microclimate conditions and dynamically changing environmental factors. Therefore, high spatio-temporal resolution data is needed, which implies adapted sampling frequency, low sensor inertia and suitable data post processing methods.

In this context, this work aims to present the portable meteorological measuring prototype, Comfy’PACK (Comfort Pedestrian Assessment of CitywalKs), to improve microclimate and pedestrian thermal comfort zoning in a dynamically changing physical urban environment. The wearable device consists of air temperature, humidity, solar radiation, wind speed and mean radiant temperature sensors, a GPS and a thermal camera. The experimental site is an identified future de-sealing site in the city of Nantes (France), aiming to improve local outdoor thermal comfort. After a detailed physical characterisation of pedestrian pathways on site, mobile measures are repeated over several days, investigating transitions between different thermal ambiances.

In this work we present the prototypes’ performances and its first application to an urban case study, evaluating small scale microclimate and thermal comfort conditions for pedestrians in relation with urban heterogeneity. Thermal comfort indicators are calculated, questioning their pertinence within various thermal environmental contexts. Data mapping will allow establishing a more detailed microclimate comfort zone classification. As part of the French research project PERMEPOLIS the findings will support the methodological development of soil de-sealing strategies and identification of alternative cool walking path in the urban space.