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Conservation Doing without and more with less. Outline  Energy conservation –Principles –Space heating –Lighting –Recycling –Transportation –Industry.

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Presentation on theme: "Conservation Doing without and more with less. Outline  Energy conservation –Principles –Space heating –Lighting –Recycling –Transportation –Industry."— Presentation transcript:

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 Area T outside T inside Q loss Material of heat conductivity, k

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 out = 35 F T in = 75 F T in = 67 F OR

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 ft 2 -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 Fiber glass 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 Insulating Sheathing Gypsum siding

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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