Mass Transfer thru Sweat “Humid and Hot'”or“Dry and Hot”？ Latent heat:Energy required for the phase change (i.e. qeap=hg·meap 侣 liquid-->gas)J/Kg Mevap Evaporation rate Kg/s ip=inA.[par(T,）-pPar(T】 五n Mass Transfer Coefficient in analogy to hf(uir.) Ts skin surface temp.;T air temp.Mass Transfer thru Sweat evap fg evap q hm = ⋅  fg h mevap  “Humid and Hot” or “Dry and Hot” ? [ ( ) ( )] m hA T T evap m s sat s sat = − ρ ϕρ∞ ∞  Latent heat : Energy required for the phase change (i.e. liquid-->gas) J/Kg Evaporation rate Kg/s m h Mass Transfer Coefficient in analogy to ~( ) n air h fu  Ts skin surface temp.; T∞ air temp