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Lecture 6

Lecture 6. Energy Conservation & Heat-Transfer Control Areas of Interest in Chapter 5: Retrofitting Building Materials House Insulation & Heating Calculations Air Infiltration Impact of Energy Conservation Measures Cooling. Fig. 5-1, p. 132. Fig. 5-2, p. 132. Table 5-1, p. 133.

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Lecture 6

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  1. Lecture 6 Energy Conservation & Heat-Transfer Control Areas of Interest in Chapter 5: • Retrofitting • Building Materials • House Insulation & Heating Calculations • Air Infiltration • Impact of Energy Conservation Measures • Cooling

  2. Fig. 5-1, p. 132

  3. Fig. 5-2, p. 132

  4. Table 5-1, p. 133

  5. Conduction Equation Qc = k x A x ΔT t d Qc = heat transfer k = material’s thermal conductivity A = surface area ΔT = temperature difference between inside & outside surfaces • = material thickness t = time

  6. Insulation factor is standardized as R = d/k • The higher the ‘R’ value, the greater the insulating ability • Qc/t = (1/R) x A x ΔT

  7. Table 5-2a, p. 134

  8. Table 5-2b, p. 134

  9. R ~ 22 to 23 Fig. 5-3, p. 135

  10. Zero energy buildings See also LEED (Leadership in Energy & Environmental Design) p. 136

  11. Fig. 5-4, p. 136

  12. Fig. 5-5a, p. 137

  13. Fig. 5-5b, p. 137

  14. How many Air Exchanges are Good? • Average is 1 complete air exchange per hour. • Almost 50% of heating bill is due to air exchange losses. • ASHRAE: 0.35 exchanges per hour. • Lack of ventilation can cause unpleasant odors • Common products and fixtures can cause irritation • Health problems from mold and mildew • Dangerous gases from combustion sources (e.g., CO) • Proper home ventilation also prevents damage: • Moisture damage: window sill rot, attic eaves, & other exposed surfaces • Moisture will also peel paint, promote infestation by insects and increase mold growth

  15. Fig. 5-6, p. 139

  16. p. 139

  17. Annual Heating Degree Days Fig. 5-8, p. 142

  18. What is a Degree Day? Degree-day (DD) = 65°F – Tavg Where Tavg = mean daily temperature per day or (TH – TL)/2 Total all degree-days and assuming negative degree-days are zero since no heating is required, then you would have previous slide.

  19. Location • Prevailing winds • Trees • Landscape contours (hills, valleys, side hill)

  20. Fig. 5-9, p. 144

  21. Table 5-3, p. 145

  22. Fig. 5-10, p. 146

  23. Project 1 • This is a team project. • Approach this as if you had a job working for a contracting company doing energy efficiency work. • Select one home from the group to do an energy study • Use the forms C1-C10 in back of your book to do survey (or the available pdf file) • Analyze home and compare calculated heating bills to heating bills as they are now • Analyze home after the improvements are hypothetically completed and estimate heating bill

  24. Format • Title page with title, home address, team personnel • Table of contents with each person’s name next to their responsibility • Short text with plain paper pictures to illustrate problem areas • Important: List all assumptions used in this report • Floor Plan sketch with dimensions • Summary paragraph • Summary of current Qtotal • Summary of improved Qtotal • Cost estimates to make improvements (use a SWAG) • Estimated savings and simple payback period • Calculation work sheets

  25. What is expected in your Project • Title Page • Table of Contents • Floor plan • Pictures of problem areas and short discussion of each • Worksheets for Qtotal as the house is now • Worksheets for Qtotal after the improvements are made • Sheet on cost of the energy improvements to home • Summary discussion paragraph on before and after results, cost of improvements, and simple payback period. Answer the question “Will it pay to make the home improvements?”

  26. Project 1 Due by July 9th This is a drop dead date. No late submissions will be accepted.

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