The error you are making is that L_st for the CET is 15 degrees East not West or -15 degrees West
Thus the Solar Time - Standard Time = 4*(-15-5.98) + E = -83.92 + E
Tim
--- Timothy P. McDowell Executive Vice President Thermal Energy System Specialists, LLC 22 N Carroll St, Suite 370 Madison, WI 53703 608-274-2577
On 2013-04-15 05:42, Fariborz Kargar wrote:
Hi again,Seville is on 37.38 N, 5.98 W. Considering the equation 1.5.2 from "Solar Engineering of Thermal Processes" (by Duffie and Beckman) we will have:1- Seville has 1 hour difference with GMT---> so: L_st = 15 * 1 = 15 degrees West(on 21st of Dec we have n=355, so B= (n-1)360/365---> B = 349.17, therefore E = 2.17 min (equation 1.5.3))Solar Time-Standard Time = 4 (L_st-L_loc) + E = 4 (15- 5.98) + 2.17 = 38.25 minutesHence on 21st of Dec at Solar Time = 12:00 we will have the local standard time equal to : 11:22at this time: solar zenith angle should be minimum. But surprisingly, this is not we see in the curves. that is why it is confusing for me. In the Graph the minimum Zenith angle happens at 8509: means 14:00- How can you interpret this discrepancy?