Apparent latent heat of evaporation from clothing: attenuation and “heat pipe” effects

• DOI: 10.1152/japplphysiol.00612.2007
• Publication Date: 2007-10-18T21:18:20Z
• Authors: George Havenith; Mark G. Richards; Xiaoxin Wang; Peter Bröde; Victor Candas; Emiel den Hartog; Ingvar Holmér; Kalev Kuklane; Harriet Meinander; Wolfgang Nocker
• Keywords: Thermal manikin

Investigating claims that a clothed person's mass loss does not always represent their evaporative heat (EVAP), thermal manikin study was performed measuring balance components in more detail than human studies would permit. Using clothing with different levels of vapor permeability and losses from skin controlled at 34 degrees C ambient temperatures 10, 20, constant pressure (1 kPa), additional wet compared dry were analyzed. EVAP based on (E(mass)) measurement direct the extra by due to (E(app)) compared. A clear discrepancy observed. E(mass) overestimated E(app) warm environments, both under overestimations observed cool depending permeability. At C, apparent latent (lambda(app)) pure cooling lower physical value (lambda; 2,430 J/g) reduced increasing resistance up 45%. temperatures, lambda(app) increases via evaporation moisture condenses inside clothing, analogous pipe. For impermeable even exceeds lambda four times 10 C. These findings demonstrate traditional way calculating person can lead substantial errors, especially for low permeability, which be positive or negative, climate type. The model presented explains subject data previously seemed contradictive.