# Energy transfer by conduction through a window

1. Apr 9, 2010

### amaryllia

1. The problem statement, all variables and given/known data
A glass windowpane in a home is 0.62 cm thick and has dimensions of 1.0 m x 2.0 m. On a certain day, the indoor temperature is 25˚C and the outdoor temperature is 0˚C.
a) What is the rate at which energy is transferred by heat through the glass?
b) How much energy is lost through the window in one day, assuming the temperatures inside and outside remain constant?

2. Relevant equations

For part a:
P = kA(delta T/L)

P = power (J/s)
k = thermal conductivity of glass, in my book it is 0.84
A = area of window = 2 m2
delta T = difference of temps from inside and outside window = 25oC
L = thickness of window = 0.0062 m

For part b:
q = P(delta T)

q = energy
P = power = 6774 J/S
delta T = 1 day = 86400 s

3. The attempt at a solution

When I solve this, I get 6774 J/s for part A, and 5.85 x 108 Joules for Part B.
Just wondering if I got the right answers/used the right equations. Thanks!

2. Apr 10, 2010

### rock.freak667

That looks like the correct method to me.