Human body's entransy balance model and entransy dissipation characteristics in a radiant cooling room

The human body, as an open thermodynamic system, has been analyzed by scholars using exergy balance models to study the irreversible heat exchange with the indoor thermal environment. However, while exergy focuses on the conversion quality and utilization efficiency of energy in work production, entransy directly characterizes heat transfer capacity. This distinction suggests that entransy may be more suitable for analyzing such heat exchange processes. Therefore, this study first established a human body entransy balance model based on Gagge's two-node energy balance model and the theory of entransy. Subsequently, a formula for calculating entransy dissipation of the human body was derived. To demonstrate its application, a radiant cooling room was analyzed as a case study to quantitatively assess the impact of indoor thermal parameters on human entransy dissipation. The results indicated that as the indoor air temperature increased from 20 °C to 30 °C, the human body's entransy dissipation first gradually decreased to a minimum before increasing greatly. This minimum dissipation point coincided well with the human body's thermal neutral state. Furthermore, the air temperature at this inflection point was influenced not only by the relative humidity but also by the difference between the mean radiant temperature and the air temperature. The proposed human body's entransy balance model and dissipation formula may offer a novel approach for designing efficient indoor thermal environments.