A picture window has dimensions of 1.40\ m\times2.50\ mZS

Alfred Martin

Alfred Martin

Answered question


A picture window has dimensions of 1.40 m×2.50 m and is made of glass 5.20 mm thick. On a winter day, the temperature of the outside surface of the glass is 20.0C, while the temperature of the inside surface is a comfortable 19.5 C. (a) At what rate is heat being lost through the window by conduction? (b) At what rate would heat be lost through the window if you covered it with a 0.750-mm-thick layer of paper (thermal conductivity 0.0500wmk

Answer & Explanation

Debbie Moore

Debbie Moore

Beginner2021-12-17Added 43 answers

We can calcualte the thermal resistance via
=0.52×102 m0.8 WmK
The rate of heat loss can be determined from
=1.4 m×2.5 m×[19.5(20)]K6.5×103m2KW
=2.1×104 W
Bertha Jordan

Bertha Jordan

Beginner2021-12-18Added 37 answers

b. Kpaper=0.05 WmK, Lpaper=0.075 cm
After converting the window with paper there will be additional thermal resistance
for Rpaper
=0.075×102 m0.05 WmK
=0.015 m2KW
=0.0125 m2KW
To calculated the rate of heat loss, calculate Rtask
=1.4 m×2.5 m×[19.5(20)]0.0125 m2KW
=6.4×103 W

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