lecture 14

Question 1

LCA

Answer 1

compilation of a products inputs and outputs and their impact through its life cycle
cradle to grave

extraction of materials
manufacturing
transportation
use
disposal
end-of-life potential

energy conversion always less than 100%

Question 2

use of LCA

Answer 2

quantifies waste
used to compare and select most sustainable options
determine part of life which contributes most emissions
help improve design
considers impact on society and environment

Question 3

single stage in product life

Answer 3

energy and raw materials go in
product is made
water, air, solid, and other waste produced

Question 4

LCA framework

Answer 4

1. goal and scope definition (describe and set system boundaries)
2. inventory analysis (identify water, energy, materials)
3. impact assessement (effects of inventory)
4. interpretation (evluate and select)

Question 5

functional unit (1)

Answer 5

quantative unit to establish a basis for comparision between other products
assures equivalence
should relate functions
(eg impact of one reusable cup and functional equivalent of dispoable cups)

Question 6

sources for life cycle inventory (2)

Answer 6

anything that quanitifies energy and raw materials at any stage of life

meter readings
lab test results
reference books
journals
published article
patents
povernment documents
reports
databases

Question 7

3. LCIA

Answer 7

life cycle impact assment

evaluation of possible human and enviromental impacts of ressources and emissions
links the product and potential impact
science-based characterization
global warming
eutrophication
acidification

uses comparisions to determine greater impact (GWP of different emissions)

Question 8

ISO standard for LCIA

Answer 8

standards for conducting impact assessment
1. selection and definition of impact categories
category of environmentall issues
based on goal and scope

examples
acidification
global warming
land use
water use

2. classification
   assigning inventory results to impact categories
3. characterization
   quantative determination of impacts from inventory results
   models impacts

Question 9

4. life cycle interpretation

Answer 9

analysis to select preferred product

two objectives
1. analyse results, draw conclusions, explain limitation, provide recommendations
2. provide a complete presentation in accordance of goal/scope

Question 10

results of LCA

Answer 10

product design may be changed
materials may be replaced
entire process may be changed

Question 11

materials flow analysis

Answer 11

used to dtermine the amount of material that is eventually converted into desired product

law of conservation of mass
input-output=accumulation
steady state output accum= 0, input=output

Question 12

materials flow efficiency

Answer 12

ratio of mass in desired product and total mass entering system

Question 13

embodied energy

Answer 13

sum of all the energy consumed during materials life cycle

can be determined by considering the energy required at each stage of the life cycle
energy total/unit mass of product
etotal/P

Question 14

materials flow system analysis

Answer 14

extraction efficiency
manufacturing efficiency
consumption efficiency
recycling effiency
system efficiency
reuse factor

Question 15

limitations of LCA

Answer 15

accuracy depends on data availability
can be resource and time consuming (weight resources against potential benefits)
does not consider product efficiency, performance, or social acceptance
(needs to be used with technical and social evaluation, not alone)
does not factor cost (needs to be used with cost-analysis)