抄録
The heat transfer rate through lined clothes was measured for various lining materials. Heat transfer resistance, which is a scale of the heat retention capability of clothes, increased as a function of the amount of lining material used per unit area. The heat transfer resistance of clothes with down lining was large, those with feather and cotton fibers were 3/4 that of down, and those with crimped polyester fiber and wool fiber were 1/2 that of down. The heat transfer coefficient of lining is given by the sum of the conductive heat transfer coefficient and the radiant heat transfer coefficient. The conductive heat transfer coefficient decreases with an increase in the thickness of the lining. The radiant heat transfer rate through the lining decreases with the shading of the lined material. The decreasing fraction in the radiant heat transfer coefficient against empty air space is defined as the shading fraction. The shading fraction increased with an increase in the amount of lining used, and the shading fraction of the down lining was large, as was the heat transfer resistance of lined clothes. The shading fraction of feather lining was small, which was the reason for the small heat transfer resistance of clothes with feather lining, despite having the same thickness as the down lining. Fiber diameters of lining fiber used were 16, 34 and 40 μm for cotton, crimped polyester and wool fibers, respectively, and the shading fraction of fiber lining for a given amount of lining per unit area increased with a decrease in fiber diameter. The shading fraction of fiber lining increased with the surface area of the lining, calculated using the fiber diameter, and was independent of the kind of lining material used. The shading fraction correlated with the surface area of the fiber lining. Down is an excellent material for retaining heat in lined clothes because of the large shading fraction of radiant heat transfer due to its large surface area consisting of stalks and small fibers, and its relatively large lining thickness per unit amount, which results in a small conductive heat transfer rate.
