1. Heat Loss through Window Panes ME 340 Heat Transfer Presentation Theron Mitchell and Nathan Cramer

2. Objective Determine difference in efficiency between dual-pane windows and single-pane windows

3. Set Up Insulated box with one side panes of glass Alcohol Thermometer Light bulb (heat source) turned on until temperature exceeds test range (50 degrees C) Thermometer shaded to remove direct radiative heating from lightbulb

4. Set Up First experiment performed using dual-pane Second experiment performed using single-pane

5. Set Up Time measured for interior temperature to drop 20 degrees C Process repeated for single and double panes

6. Results Amount of time Amount of time required for temperature drop consistently 40-50% longer for double pane glass

7. Heat Flux Example Temperature difference (exterior temp to interior temp) = 38 degrees C (Approx 68 degrees F) Double Pane Windows q” = 640 W/m^2 Single Pane Windows q” = 975 W/m^2

8. Conclusion Double pane windows are approximately 40% more efficient than single pane windows