Evaluating thermal response when elderly people using local cooling devices: Correlation among overall and local thermal sensation with skin temperature

The thermal comfort of elderly people in warm indoor environments is important because of their higher risk of heat stress. The use of local cooling devices may help alleviate heat stress. In this study, 26 elderly participants were recruited for climate chamber experiments in neutral (26 degrees C, 40 % relative humidity (RH)), slightly warm (29 degrees C, 40 % RH; 28 degrees C, 60 % RH), and warm (33 degrees C, 40 % RH; 32 degrees C, 50 % RH) environments. Three local cooling devices were tested: a table fan, evaporative cooling device, and air-cooled jacket. This study found, in different warm environments, the use of local cooling devices by the elderly results in an mean skin temperature decrease of no more than 0.5 degrees C. The thermal sensation in the head and torso has the most significant impact on overall thermal sensation. The mean skin temperature (MST) remains an effective physiological indicator for estimating overall thermal sensation after using local cooling devices. The skin temperature in the head, limbs, and extremities plays a substantial role in predicting overall thermal sensation. The thermosensory mean skin temperature (TMST) proposed based on the skin temperature of these parts can more accurately predict overall thermal sensation than MST. This study provides a reference for the development of future local cooling devices. This study has implications for guiding the selection of devices for nursing homes or residential environments for the elderly, and it can be utilized to formulate recommendations for improving device design.