Question

Rate of heat leaving +rubric for answering question!

A window pane that measures 20.0 cm by 15.0 cm is set into the front door of a house. The temperature outdoors is -15.0° C and inside is 22.0° C. If the glass is 0.32 cm thick, at what rate does heat leave the house through the window? If the single paned window is replaced with a double paned window with an air gap of 0.50 cm between the two glass panes, each 0.32 cm thick, at what rate does heat leave the house through the double paned window? a) b)

Answer 1

(a) At what rate does heat leave the house through the window?

using a formula, we have

(Q / t) = $\kappa$ A (T_in - T_out) / d

where, $\kappa$ = thermal conductivity for the glass = 0.75 W/m ⁰C

T_in = inside temperature = 22 ⁰C

T_out = outside temperature = - 15 ⁰C

d = thickness of the glass = 0.32 cm = 0.0032 m

A = area of the glass = (0.2 m) (0.15 m) = 0.03 m²

then, we get

(Q / t) = (0.75 W/m ⁰C) (0.03 m²) [(22 ⁰C) + (15 ⁰C)] / (0.0032 m)

(Q / t) = [(0.8325 W.m) / (0.0032 m)]

(Q / t) = 260.1 W