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Home Depot Windows

Home Depot Windows

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Home Depot Windows

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Presentation Transcript

  1. Home Depot Windows Autumn Glenn Phil Harris ME 340 – Winter 2009

  2. Introduction • Validate Home Depot Claims • Justification • Economic troubles lead people to look for ways to significantly save money • Sometimes advertising draws people to a product for only marginal benefits • Validate Calculator model they used

  3. Home Depot Claim • Single vs. Double • 6500 Series • Vinyl Window • Premium Line with Argon gas • Calculator ** Percentages very similar**

  4. Heat Transfer Problem • Analyze Single and Double Paned Windows, Compare • Analyze Single Pane • Forced Convection Inside and Outside • No Free Convection (Inside or Outside) • Radiation • Wall Inside to Window • Window to Wall • No Solar Radiation • Conduction through the window Outside Inside T ∞ = 293 K hi = 100 W/m2K T ∞ = 273 K ho = 250 W/m2K Forced Convection Forced Convection Wall to Window Window to Wall Conduction εwall = .89 ε window = .9

  5. Heat Transfer Problem Outside Argon k=.0156W/m2K Inside • Analyze Double Pane • No Free Convection (Inside or Outside) • Radiation • Wall Inside to Window • Window to Wall Inside • Pane 1 to Pane 2 • Pane 2 to Pane 1 • No Solar Radiation • Free convection inside the window • Forced Convection Inside and Outside • No Conduction (based on single pane results 277.8 – 276) T ∞ = 293 K hi = 100 W/m2K T ∞ = 273 K ho = 250 W/m2K Free Convection Forced Convection Forced Convection Wall to Window Window to Wall Pane 1 to Pane 2 εwall = .89 ε window = .9 Pane 2 to Pane 1

  6. Results of Analysis • Single Pane • Heat Loss, q = 2,361 Watts • Double Pane • Heat Loss, q = 807 Watts • Projected Savings of Double vs. Single • (807/2,361) = 34.2% • Error = Assumptions and Simplifications

  7. Berkeley National Laboratory • Contributing Factors • House type • Single-story or Two-story • Geographic location • Orientation, • Electricity and gas cost, • Building configuration details (such as wall, floor, and HVAC system type) • Windows • Size • Shading • Thermal properties

  8. Conclusion and Recommendations • Conclusion • Double pane are more energy efficient • Home Depot's results are reasonable • Accurate Calculator • Recommendations • High cost of more efficient windows may not be realized for years – Do research • Use the tools out there – Be an Engineer • Link To Calculator (Named “RESFEN”) http://windows.lbl.gov/software/resfen/31/default.htm

  9. Appendix MathCad Screen Shot