Human Body Exergy Analysis Model in Building Thermal Comfort Evaluation

Abstract

To explore the application of the human body exergy analysis method in assessing the indoor thermal environment, strictly according to the definition of metabolic exergy, based on the two existing exergy analysis models, a more reasonable calculation method of metabolic exergy was first proposed and established, which is a new two-node exergy analysis model. Then, the experimental data in the ASHRAE database were used to verify the reliability of the established model. Finally, the human body exergy exchange rate and exergy loss rate with indoor and outdoor environmental parameters were revealed. The research results show that the new metabolic calculation method can more accurately analyze the human body’s exergy; the exergy loss rate is larger than the exergy exchange rate in the metabolic exergy rate; when the operating temperature is 25∘C, the exergy exchange rate mainly includes the radiation exergy rate and the convective exergy rate; operation at a temperature of 32∘C, the evaporation rate and respiration rate are the main components of the exergy exchange rate; the human body’s exergy loss rate has extreme values at low or high operating temperatures, and it is used separately for the evaluation of human thermal comfort. Combining the exergy loss rate and the exergy exchange rate can better evaluate the indoor thermal environment, the minimum exergy loss rate and the minimum exergy exchange rate under the given indoor conditions, both occur under outdoor high-temperature and low humidity conditions; outdoor temperature affects the human body exergy loss rate and human body exergy exchange rate more strongly than outdoor relative humidity.