A comparative field study of occupants’ thermal exposure in non-heating and decentralized heating environments

Abstract

Winter heating in the Hot Summer and Cold Winter (HSCW) region is a widely debated topic. This study aims to compare adaptive thermal comfort and the thermal exposure of occupants in non-heating and decentralized heating environments and enhance understanding of the dynamic thermal adaptation process under different indoor thermal conditions. A five-month follow-up field study on thermal comfort and adaptive behaviors was conducted in eight decentralized heating and 12 non-heating apartments in Chongqing, China. The results indicated that the indoor thermal environment and occupants' thermal comfort had been improved significantly with decentralized heating. In the heating period, the heated group's monthly average indoor air temperature was 2.8 °C (K) higher than that in the unheated group, and the thermal sensation vote of ‘neutral’ increased by 5%. Behavioral adaptation was used to explain the differences in the occupants' thermal comfort and neutral temperature between the heated and unheated groups. Thermal exposure to decentralized heating elevated the group's vigilance to cold conditions. Decentralized heating was found to have an asymmetric and moderate effect on thermal adaptation processes as indicated by the defined index “difference factor”. This evolution of neutral temperature was skewed to the right and had a one-week delay in response to the change of indoor air temperature. The thermal adaptation varied dynamically by invoking adjusting adaptive methods flexibly, and the potential of adaptability was malleable in the decentralized heating environment. It is suggested that the set-point of the heating temperature does not exceed 18.0 °C to preserve occupants' thermal adaptability.