1 / 11

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

diane
Télécharger la présentation

Conservation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

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 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.

More Related