Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Energy transfer by conduction through a window

  1. Apr 9, 2010 #1
    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. jcsd
  3. Apr 10, 2010 #2


    User Avatar
    Homework Helper

    That looks like the correct method to me.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook