Heat Loss through Window Panes

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Heat Loss through Window Panes
ME 340Heat Transfer Presentation
Theron MitchellandNathan Cramer
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Objective

• Determine difference in efficiency between
  dual-pane windows and
  single-pane windows

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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

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Set Up

• First experiment performed using dual-pane
• Second experiment performed using single-pane

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Set Up

• Time measured for interior temperature to drop
  20 degrees C
• Process repeated for single and double panes

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Results

• Amount of time
• Amount of time required for temperature drop
  consistently 40-50 longer for double pane glass

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Heat Flux Example

• Temperature difference (exterior temp to interior
  temp)
• 38 degrees C (Approx 68 degrees F)
• Double Pane Windows q 640 W/m2
• Single Pane Windows q 975 W/m2

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Conclusion

• Double pane windows are approximately 40 more
  efficient than single pane windows