1. 14-6 Heat Transfer: Conduction
Experimentally shown the following: The heat flow per unit time is given by
(14-5)

2. 14-6 Heat Transfer: Conduction
Building materials are measured using R−values rather than thermal conductivity:
Experimentally shown the following: The heat flow per unit time is given by
(14-5)

3. 14-6 Heat Transfer: Conduction
(14-5)
𝑄= 𝑘 𝐿 𝐴 (𝑇 1 − 𝑇 2 )𝑡
Σ 𝑅 𝑖 = 𝑅 1 + 𝑅 2 +…+ 𝑅 𝑖
𝑄= 1 𝑅 𝐴 (𝑇 1 − 𝑇 2 )𝑡
𝑄=𝐴 𝑇 1 − 𝑇 2 𝑅 𝑡

4. 14-6 Heat Transfer: Conduction
2. A thermopane window consists of two glass panes, each 0.6 cm thick, with a 1-cm-thick sealed layer of air in between. If inside the room temperature is 230C and the outside temperature is 00C, determine the rate of energy transfer through 1m2 of the window. ( k=0.84 J/smK kair = J/smK )