Exergy Analysis of Human Respiration Under Physical Activity

Abstract

This paper presents an exergy analysis of the human body under physical activity. A model of the respiratory system and a model of the thermal system were used for this purpose. These models consider heat and mass transfers in lungs, tissues and blood. Each component of these models is represented by a uniform compartment governed by equations for diffusion, convection, O2 consumption, CO2/heat generation and heat and mass transfer with the environment. The models allow the calculation of the exergy destruction in the lung and tissues, and the contribution of each entropy generation mechanism in the total generation. Furthermore, a discussion is proposed regarding the efficiency of the human body under physical exercise.