Heat is transferred at a rate of 0.1 kW through glass wool insulation (density = 100 kg/m3 ) with a 5 cm thickness and 2 m2 area. If the hot surface is at 70°C, determine the temperature of the cooler surface.
GIVEN
• Glass wool insulation with a density (?) = 100 kg/m3
• Thickness (L) = 5 cm = 0.05 m
• Area (A) = 2 m2
• Temperature of the hot surface (Th) = 70°C
• Rate of heat transfer (qk) = 0.1 kW = 100 W
FIND
• The temperature of the cooler surface (Tc)
ASSUMPTIONS
• One dimensional, steady state conduction
• Constant thermal conductivity
SKETCH
PROPERTIES AND CONSTANTS
The thermal conductivity of glass wool at 20°C (k) = 0.036 W/(m K)
For one dimensional, steady state conduction, the rate of heat transfer is
Solving this for Tc
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