How do geometric forms of public squares affect year-round thermal comfort? A field study in a cold coastal city

Abstract

This study investigates the effects of geometric forms on thermal comfort in public squares in cold coastal cities. Field measurements were conducted across four representative squares during typical meteorological days throughout the year to collect climatic parameters, along with skin temperature and thermal comfort from 16 healthy university students. The Universal Thermal Climate Index (UTCI) was used as the thermal index, revealing differences in microclimatic conditions, physiological parameters, and thermal comfort. The results show that: (1) Geometric forms significantly influence microclimate and thermal comfort. Enclosure levels and sky view factor (SVF) primarily impact temperature, wind speed, and solar radiation, while orientation introduces seasonal variations through monsoon and maritime effects. (2) Higher enclosure levels and lower SVF are associated with higher neutral Universal Thermal Climate Index (NUTCI) values, with semi-enclosed spaces showing a broader thermal neutrality range. (3) Geometric forms affect the sensitivity of mean skin temperature (MST) to thermal changes, with lower SVF resulting in higher MST under neutral thermal sensation (TSV = 0). (4) In Dalian, the NUTCI for neutral thermal sensation ranges from 11.80 °C to 21.90 °C, while the no thermal stress range spans 5 °C to 31.80 °C. These findings provide insights for designing and renovating public squares in cold regions to improve outdoor thermal comfort and encourage outdoor activities.