Abstract:
Traditional methods of human thermal comfort analysis are based on the first law of thermodynamics. These methods use an energy balance of the human body to determine heat transfer between the body and its environment. By contrast, the second law of thermodynamics introduces the useful concept of exergy. It enables the determination of the exergy consumption within the human body dependent on human and environmental factors. Human body exergy consumption varies with the combination of environmental (room) conditions. This process is related to human thermal comfort in connection with temperature, heat, and mass transfer. A thermodynamic analysis of human heat and mass transfer based on the 2nd law of thermodynamics in presented. It is shown that the human body’s exergy consumption in relation to selected human parameters exhibits a minimal value at certain combinations of environmental parameters. The expected thermal sensation also shows that there is a correlation between exergy consumption and thermal sensation. Thus, our analysis represents an improvement in human thermal modelling and gives more information about the environmental impact on expected human thermal sensation. Exergy is only conserved, or in balance, for a reversible process, but is partly consumed in an irreversible process. For a real process the exergy input always exceeds the exergy output; this imbalance is due to irreversibilities and represents exergy destruction or exergy consumption.
In the present work, thermal variations was observed on 16 bodies part of human body and each part was carefully monitored on the basis of their thermal nature. A new thermal comfort questionnaire has been designed for gathering thermal sensation votes and Predicted mean vote was made based on the questionnaire taken from the subjects.
