sin αst

CONCEPTUALISATION
concepts. This approach assists in making subjective opinions, about one alternative solu-
tion versus another, more objective. The evaluation criteria do not vary markedly in im-
portance and they are thus not weighted in the conceptual phase. This is in accordance
with the recommendations of VDI Guideline 2225 [27] that suggests omitting the use of
weighting factors due to the fairly low level of information in this early development stage
[7, p. 194].
Each solution’s compliance to the evaluation criteria is rated on a 0-4 scale that is elabo-
rated on figure 4.15. Points 0 and 4 are only awarded if the solution characteristics are
excessive, that is, unsatisfactory or very good (ideal).
Pts. Meaning
0
Unsatisfactory
1 Just tolerable
2 Adequate
3 Good
4 Very good (ideal)
Figure 4.15: Meaning of the evaluation points (as recommended in VDI Guideline 2225) [27]
The qualitative evaluation criteria, adopted from the requirement specification, are listed
and rated for each wind turbine variant in table 4.2.
29