A local thermal sensation model suitable for thermal comfort evaluation of sensitive body segments

Abstract

Nowadays, an indoor environment is created by heating, ventilation, air-conditioning, and cooling (HVAC) systems that meet the cooling needs of occupants in summer, however, local thermal discomfort (like joint discomfort) is widespread. Existing studies have focused on local thermal sensation models to predict the thermal comfort of non-sensitive body segments (like the forehead) but only a few reports have focused on the thermal sensation of sensitive body segments. The existing models cannot be directly applied to predict the thermal comfort of sensitive body segments (joints). To address this problem, the present investigation first assessed the correlation between the thermal sensation voting (TSV) of sensitive and non-sensitive body segments. Subsequently, this study established a local thermal sensation model based on the skin temperature to evaluate the thermal sensation of body segments, especially the sensitive segments (joints). In the proposed model, the sensitivity coefficient, k, and the cold tolerance coefficient, c, were introduced. The k value represented the sensitivity of the body segments, while the c value reflected the point whereby the body segment began to significantly feel cold. By changing the k and c values, different local characteristic curves across body segments were obtained. Finally, this research validated the accuracy of the proposed model, and its prediction accuracy was within 15% when the deviation of TSV was ±1. Thus, the proposed local thermal sensation model could be applied for adjusting indoor parameters, and meeting local thermal needs on demand is the key to exploring the relationship between humans and the environment.