CE 11 Homework 3

CE 11 Homework 3 - C E 11 Homework 3 NEP and LCA Stephen...

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CE 11 Homework 3: NEP and LCA Stephen Hom 2/18/2009 1. NEP = NPP – C/ , where = -1921(1/(283.15-139.4)-1/(MAT-139.4)) τ τ Annual NEP rf = 1.44 – 10/[-1921(1/143.75-1/(303-139.4))] = 7.61 kg of C/m 2 Annual NEP ds = 0.32 - .30/[-1921(1/143.75-1/(295-139.4))] = .615 kg of C/m 2 NEP rf / NEP ds = 7.61/.615 = 12.4 2. (a) The different amounts represent an equal carrying capacity. In general, 1 paper bag carries the same amount of stuff as 2 plastic bags. (b) The production of plastic bags consumes less energy than the production of paper bags. This view is confirmed by all three studies. (c) According to two of the studies, the production of plastic bags contributes far fewer air pollution emissions than the production of paper bags. The Clambrone study, however, shows no major difference in air pollution emissions between the two materials. (d) One factor that might be responsible for differences in the data is different LCA models may have been used. Thus, different "sectors" contribute different values to the same input data. Another factor is that the studies may have used different plastic and paper bags.
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CE 11 Homework 3 - C E 11 Homework 3 NEP and LCA Stephen...

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