Example of Calculation of the Shading Correction Factor kB

Using Figure 2.34, the calculation procedure for shading correction factor kB for a solar generator at 47°N with b = 45° and g = 15° will now be described. After the solar generator azimuth g = 15° and the horizon have been entered in the shading diagram for 47°N, it emerges that shading occurs only from October to February. Hence kB needs to be determined for this period.

The following is obtained for October’.

SGPS = 21 ■ 3% + 15 ■ 2% + 5 ■ 1% = 98%

SGPB = 1 ■ 2% + 1 ■ 1% = 3% ) kB = 1 – SGPB/SGPS = 0.97 The following is obtained for November.

SGPS = 23 ■ 3% + 12 ■ 2% + 2 ■ 1% = 95%

Подпись: Shadowing Diagram for 47° N I 1% | 2% | 3% | 2% | 1% | Solar azimuth YS in Grad

SGPB = 2 ■ 2% + 2 ■ 1% = 6% ) кв = 1 – SGPB/SGPS = 0.94

Figure 2.34 Complete shading for kB calculation, with the solar generator azimuth and the horizon entered

The following is obtained for December:

SGPS = 25 ■ 3% + 12 ■ 2% = 99%

SGPB = 2 ■ 3% + 5 ■ 2% = 16% ) kB = 1 – SGPB/SGPS = 0.84 The following is obtained for January:

SGPS = 24 ■ 3% + 12 ■ 2% + 1 ■ 1% = 97%

SGPB = 1 ■ 3% + 4 ■ 2% + 1 ■ 1% = 12%

) kB = 1 – SGPB/SGPS = 0.88

The following is obtained for February:

SGPS = 21 ■ 3% + 14 ■ 2% + 4 ■ 1% = 95%

SGPB = 1 ■ 2% + 2 ■ 1% = 4% ) kB = 1 – SGPB/SGPS = 0.96

With kB = 1 for the remaining months.

Section A5 contains shading diagrams for 41, 44, 47, 50 and 53°N that were realized using the same method, as well as an assessment diagram with the same scale, which can be used as a master copy. These documents allow for sufficiently accurate calculation of the shading correction factor kB for Central Europe and much of Southern Europe.

Подпись: Direct beam energy on an inclined surface: HGB — kB ■ RB ■ HB — kB ■ RB ■ (H — HD) (2.24)

The shading correction factor kB can in turn be used to calculate irradiated direct beam energy in a manner that takes account of shading. This calculation is performed in the guise of a correction of Equation 2.15 by multiplying by kB:

Updated: August 2, 2015 — 7:55 pm