A cool early spring breeze passes over the roof of a poorly-insulated home. The surface area of the roof is 250 m2, and the temperature of the roof is maintained at 20°C from heat escaping the house. The air temperature is 5.0°C, and the convective heat transfer coefficient is 12.0 W/m2-K. Determine the rate of convective heat transfer from the roof.
Given: A = 250 m2; Tf = 5.0°C; Ts = 20°C; h = 12.0 W/m2-K
What will be an ideal response?
Qconv = hA(Tf -Ts) = (12.0 W/m2-K)(250 m2)(5°C - 20°C) = 45,000 W = -45.0 kW
Heat is lost from the roof to the air.
You might also like to view...
____________________ refers to the initial value, setting, or configuration prior to any user changes.
Fill in the blank(s) with the appropriate word(s).
The illumination from a point source 4 ft. above a surface is 100 foot-candles, and the surface is normal to the source. What will be the illumination level if the surface is tilted 45°?
A) 50 foot-candles. B) 100 foot-candles. C) 71 foot-candles.
What are the characteristics of lizards?
What will be an ideal response?
The scanning device many teachers use to read computer answer sheets would be classified
as a processor.
Indicate whether the statement is true or false.