A 1 m X 1 m glass window is 3 mm thick. If the temperature is -10 C outside and 20 C inside how much heat will pass through the window in 1 hour?

Question

A 1 m X 1 m glass window is 3 mm thick.  If the temperature is -10 C outside and 20 C inside how much heat will pass through the window in 1 hour?

jamesj · Answer

ok, what have have you learnt about thermal conductivity?

jamesj · Answer

You need to have some basic theory of energy being transmitted through materials.  In particular, if a material has thermal conductivity of $ k $, an  area $ A $, thickness $ d $ and a temperature difference across both sides of the material of $ \Delta T $ for temperature, then the rate of heat transfer is
$$ Rate = \frac{kA\Delta T}{d} $$

jamesj · Answer

The units of the rate is Watts = Joules/sec.

Now, in your problem, you are given $ A, d, \Delta T $.  Do you know $ k $ for glass?  If so, you can calculate the rate for this pane of glass.

From that you can find how many Joules are transferred in one hour = 60^2 seconds.

jamesj · Answer

Make sense?  Looking familiar?

anonymous · Answer

the specific heat or heat capacity of glass is 840J/kg x K is that the k?

jamesj · Answer

No.  You want the thermal conductivity of glass, which is a different quantity.