Editing Diffuse sky radiation (section)

==As a part of total radiation==
One of the equations for total solar radiation is:<ref>{{cite book|last1=Mukherjee|first1=D.|last2=Chakrabarti|first2=S.|title=Fundamentals of Renewable Energy Systems|url=https://books.google.com/books?id=fdxdezgeXAcC&pg=PA22|year=2004|publisher=New Age International|isbn=978-81-224-1540-7|page=22}}</ref>

: <math>H_t= H_b R_b + H_d R_d + (H_b+H_d) R_r </math>

where ''H<sub>b</sub>'' is the beam radiation irradiance, ''R<sub>b</sub>'' is the tilt factor for beam radiation, ''H<sub>d</sub>'' is the diffuse radiation irradiance, ''R<sub>d</sub>'' is the tilt factor for diffuse radiation and ''R<sub>r</sub>'' is the tilt factor for reflected radiation.

''R<sub>b</sub>'' is given by:

: <math>R_b=\frac{\sin(\delta) \sin(\phi-\beta)+ \cos(\delta)\cos(h) \cos(\phi-\beta)}{\sin(\delta) \sin(\phi)+ \cos(\delta)\cos(h) \cos(\phi)}</math>

where ''δ'' is the [[solar declination]], ''Φ'' is the latitude, ''β'' is an angle from the horizontal and ''h'' is the solar [[hour angle]].

''R<sub>d</sub>'' is given by:

: <math>R_d=\frac{1+\cos(\beta)}{2}</math>

and ''R<sub>r</sub>'' by:

: <math>R_r=\frac{\rho(1-\cos(\beta))}{2}</math>

where ''ρ'' is the [[reflectivity]] of the surface.