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Conservation

Conservation. Doing without and more with less. Outline. Energy conservation Principles Space heating Lighting Recycling Transportation Industry. Why conservation?. Electricity Conservation saves 3 X as much fuel as the energy you don’t use. Therefore, a 3-fold reduction in pollution

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Conservation

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  1. Conservation Doing without and more with less

  2. Outline • Energy conservation • Principles • Space heating • Lighting • Recycling • Transportation • Industry

  3. Why conservation? • Electricity Conservation saves 3 X as much fuel as the energy you don’t use. • Therefore, a 3-fold reduction in pollution • Saves money • Deprivation: Dealing with less. • Efficiency: Doing more with less

  4. Home heating • The goal is to maintain a constant, comfortable temperature. • Therefore, Heat in = Heat out. • Heat out: • Conduction (50-70%) • Convection (up to 30%) • Radiation (5-10%)

  5. Conduction losses • The rate of heat loss (power loss) is proportional to the temperature difference and the surface area. • Qloss/t = k A T Material of heat conductivity, k Area T outside T inside Q loss

  6. Reducing heat losses • Heat loss is proportional to temperature difference. • Q1 / Q2 = T1 / T2 • Q1/Q2 = (67-35)/(75-35) = 32/40 = 80% • A 20% savings. T in = 75 F OR T out = 35 F T in = 67 F

  7. The law of heat conduction • Q loss / t = A T / R • R is the R-value, which is a measure of the resistance to heat loss for a given material of given thickness. • i.e. R fiberglass = 3.7 ft2-F-hr/Btu per inch. • The higher R, the lower the heat loss. • Example: A single pane of glass has R = 1 Q loss(glass)/Qloss(fiberglass) = (1/Rglass)/(1/Rfiber) = 3.7 X more loss.

  8. An insulated wall Air layers: In: R = .17 R = .68 Insulating Sheathing: R = 2.06 Fiberglass: R = 11.0 Gypsum siding: R = .45 R total = 14.36 Air layers Fiber glass Gypsum siding Insulating Sheathing

  9. Heating needs • HDD = The length of the heating season, in days, times the average temperature difference • HDD = 150 days (65 F – 35 F) = 4,500 • Macomb has 6000 HDD • Heating need per season: Qtotal = HDD (Area)(24 hrs/day)  R An 8 x 20 foot wall with R = 14.36 in Macomb. Q total = 6000 (160 ft^2)(24) / 14.36 = 1.6 x 10^6 Btu/season. Natural Gas costs 40c per 1 x10^5 Btu, so $6.4 dollars burned to make up loss from that wall.

  10. Air infiltration • Typical house exchanges air with outside every hour. • Good insulation can reduce that to every 5 hours. • Must have better air-purifying

  11. Lighting and Electrical use • Fluorescent bulbs have 10 X longer lifetime, and use 15 W compared to 75W, representing an energy savings of 5 x, and a money savings of 50 x. • Leaking electricity – Most appliances don’t turn fully off. Up to 5% of America’s use of electricity for “standby”mode.

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