Study on thermal comfort and optimization strategies in outdoor open spaces of hospitals in cold regions of China during summer

This paper aims to explore the differences in thermal comfort in outdoor open spaces with different thermal environmental backgrounds (under the ward building (DW) and outdoor garden (OG)) at a hospital in Xi'an, a city in a cold region of China. Meteorological measurements and a thermal comfort survey were conducted from May to July to assess the spatiotemporal location and thermal perceptions of patients and accompanying people. The Universal Thermal Climate Index (UTCI) was used to determine thermal benchmarks. Additionally, we employed two research methods: on-site meteorological measurements and questionnaire surveys. Results indicate that: 1) DW generally remained cooler than OG. During the early summer, "Slightly warm" was the predominant sensation, changing to "Warm" and "Slightly warm" in both areas during the midsummer. 2) Respondents in DW exhibited higher thermal sensitivity and acceptance, with a higher neutral UTCI (DW = 26.16 C-degrees, OG = 21.00(degrees)C) and a broader neutral UTCI range (DW = 21.22 C-degrees-31.10 C-degrees, OG = 15.41 degrees C-26.40 C-degrees) compared to OG. 3) People have adaptability to the thermal environment, their tolerance to heat is stronger in midsummer than in early summer (NUTCI: In early summer = 22.72 C-degrees, in midsummer = 24.86(degrees)C), and people living in warmer environments have higher adaptability to heat and lower thermal sensitivity.