measurement and comparison of solar radiation estimation models ...

Evaluation of Group 1:
There is only one equation in this group. The results for MBE = -595.294 W/h,
RMSE = 685.838 W/h, t-stat=5.797 and e=-12.727 were obtained from Eq. 4.1.
Evaluation of Group 2:
There are two equations in this section. They were Eqs. 4.7 and 4.10. The best
results for MBE = -10.324 W/h, t-stat=0.100 and e=-0.2207 were obtained from Eq.
4.10 and best results for RMSE = 325.248 W/h from Eq. 4.7.
Evaluation of Group 3:
Six models were compared in this part. The best results for MBE = -0.968 W/h,
RMSE = 337.305 W/h, t-stat=0.010 and e=-0.0207 were obtained from the new
developed model Eq. 4.11.
Evaluation of Group 4:
There were also two models in this group. The best results for MBE = 1.112
W/h, t-stat=0.007 and e=0.02377 were obtained from the new developed Eq. 4.12 and
the best result RMSE = 440.037 W/h was obtained from Eq. 4.8.
Among the solar radiation models, for all test methods, the author’s model given
by Eq. (4.14) was found to be the most accurate model, followed by Eq. (4.13) and Eq.
(4.12) respectively. By looking at the relative percentage errors, it has seen that the new
developed models gave the closest values rather than the other models. They were
followed by Eq. (4.9) and Eq. (4.7).
Table 12. Comparison of statistical methods for global solar radiation models
Method
Model
MBE ( W/m²) RMSE ( W/m²) t-stat e%
1 -595,294 685,838 5,797 -12,727
2 -213,304 409,644 2,023 -4,5603
3 -202,884 406,316 1,911 -4,3375
4 225,261 350,564 2,781 4,81593
5 -409,445 575,035 3,363 -8,7537
6 -222,139 417,388 2,085 -4,7492
7 113,374 325,248 1,233 2,42385
8 -260,684 440,037 2,439 -5,5733
9 -158,001 365,375 1,591 -3,378
10 -10,324 343,676 0,100 -0,2207
11 -0,968 337,305 0,010 -0,0207
12 1,112 530,150 0,007 0,02377
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