Tuesday, 30 June 2009

[week 20] multi criteria comparison

The same functional unit requirements makes it possible to compare the system designs. System design 4 is not complying to the requirement of a thin rod package because of the bracings.

There is some uncertainty in use time, dimensions and environmental index. Especially the kenaf core construction still has some uncertainties and topics for further research.

The C2C bonus is the added value of the material next to the functional unit. Biosphere materials have the possibility of energy recovering after use.

The table below compares known variables for an end grade. Higher numbers are better. Numbers are therefore normalized with best practice =1.

name

function

Environmental index

C2C bonus

total +factor

1. technical

o

0,19

+- 10%

O

0,19

2. steel-

wood

o

0,13

+- 10%

O

0,13

3. kenaf

core tube

o

0,56

+- 10%

+

0,84

4. wood

joints

-

1,0

+- 10%

+

1

5. solid

wood

o

0,1

+- 10%

+

0,15

Because of not fitting the functional unit the wood joints are not chosen as final design.

Kenaf core tubes are the best option in total.


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