Predicting thermal comfort of residential shower rooms for optimal showering energy use

Showering is a typical daily activity directly related to people's comfort and health, dominating thermal energy consumption in residential buildings. This study developed a mathematical model to predict people's mean skin temperature (MST) and dynamic thermal sensation (DTS) during undressing and standing showering periods to identify the comfortable showering environment for different occupants. The model's validity was supported by comparing the calculated MSTs with the results collected by a previous experimental study. Moreover, 31 subjects (of different sexes, weights, and heights) were involved in the case studies. Results of the case studies showed that female and underweight subjects' MST and DTS varied more significantly than male and overweight subjects during undressing and showering periods. Additionally, it was found that both water and air temperatures significantly impact occupants' MST and DTS during showering, and the impact of water temperature was much more significant than the impact of air temperature. Moreover, by combining a previously developed energy consumption model, an optimal showering environment can be identified where both maintaining comfort and saving energy can be achieved. Based on the simulation results, the water temperature during showering was suggested to be not higher than 40 °C, especially for longer showering, to avoid thermal discomfort and energy overconsumption. However, the model was established based on theoretical deduction, with assumptions made. Additional measurements were needed to validate the model further and improve it.