5 
the following model allows calculation of the angle of incidence of 
the following model allows calculation of the angle of incidence of 
6 
sunlight onto an inclined surface 
sunlight onto an inclined surface 
7 


8 
The equation of time has been changes to the Duffie & Beckman 2nd edition 
The equation of time has been changed to the Duffie & Beckman 2nd edition 
9 
form, cited as coming from Iqbal 1983. The equation for 'B' has also 
form, cited as coming from Iqbal 1983. The equation for 'B' has also 
10 
been changed to the 2nd Ed D&B form. 
been changed to the 2nd Ed D&B form. 
11 


12 
For the longitude correction we use the spherical geometry convention 
For the longitude correction we use the spherical geometry convention 
13 
of making east positive. D&B are americocentric, obviously :) 
of making east positive. D&B are americocentric, obviously :) 
14 


15 

See further notes and references at the end of the file. 
16 


17 
by John Pye, 2006 
by John Pye, 2006 
18 
*) 
*) 
19 
MODEL sunpos; 
MODEL sunpos; 
233 
END values; 
END values; 
234 
METHOD self_test; 
METHOD self_test; 
235 
ASSERT abs(delta  (13{deg})) < 0.5{deg}; 
ASSERT abs(delta  (13{deg})) < 0.5{deg}; 
236 
ASSERT abs(R_b1.80) < 0.005; 
ASSERT abs(R_b1.80) < 0.05; 
237 
END self_test; 
END self_test; 
238 
END example_1_7_3; 
END example_1_7_3; 
239 

