A method for setting room temperature of district heating in northern China based on local thermal comfort

Abstract

Currently, the district heating system in northern China primarily employs two types of terminals, namely radiators and radiant floors. The heating design temperature is set for the center of the room without considering local thermal comfort for individuals. As the real thermal environment within buildings is non-uniform, variations in thermal sensation across different parts of the body will affect whole-body thermal comfort. Therefore, it is crucial to prioritize local thermal comfort when setting room temperatures for heating purposes. In this study, we analyzed the data from the chamber experiments and Chinese Thermal Comfort Database, focusing on the district heating environments of residences, office buildings, and university classrooms in severe cold and cold zones. We developed a thermal sensation evaluation model for analyzing the most uncomfortable body part, investigated the lower limit of acceptable air temperature for this specific body part and inferred appropriate setpoint based on both this limit and head-ankle temperature difference. The results indicate that ankles are the most uncomfortable part with an estimated lower limit of acceptable air temperature at approximately 18 °C. Consequently, we recommend setting room temperatures of 20 °C for radiator heating (RH) and 19 °C for floor heating (FH) to ensure ankle thermal comfort. The findings of this study can provide theoretical basis for reasonable settings of heating room temperature for the aforementioned three types of buildings in northern China, thereby further achieving energy conservation.