Fundamental characteristics of the transient response of a heat and moisture exchanger with a CaCl ₂ component

The fundamental characteristics of a medical heat and moisture exchanger with filter (HMEF), the artificial nose, were investigated experimentally and numerically. Transient changes in the temperature and humidity in HMEF were measured. Saturated air at 37°C simulating exhalation by a patient was fed into the HMEF for 180 s, then dry air at 26°C simulating inhalation was fed in the opposite direction. CaCl ₂ installed in the HMEF intensified the condensation of water and retained water in the HMEF. The water vaporized in the returning dry air, allowing and a patient to inhale air with some humidity. The results also revealed that the condensed water can not be completely returned to the inhalation supply. The numerical results showed the difference in the process of condensation and vaporization.