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<p>The error you are making is that L_st for the CET is 15 degrees East not West or -15 degrees West</p>
<p>Thus the Solar Time - Standard Time = 4*(-15-5.98) + E = -83.92 + E</p>
<p>Tim</p>
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<pre>---
Timothy P. McDowell
Executive Vice President
Thermal Energy System Specialists, LLC
22 N Carroll St, Suite 370
Madison, WI 53703
608-274-2577</pre>
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<p>On 2013-04-15 05:42, Fariborz Kargar wrote:</p>
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<div dir="ltr"><span style="font-family: arial,sans-serif; font-size: 13px;">Hi again, </span>
<div style="font-family: arial,sans-serif; font-size: 13px;">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:</div>
<div style="font-family: arial,sans-serif; font-size: 13px;">1- Seville has 1 hour difference with GMT---> so: L_st = 15 * 1 = 15 degrees West</div>
<div style="font-family: arial,sans-serif; font-size: 13px;">(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)) </div>
<div style="font-family: arial,sans-serif; font-size: 13px;">Solar Time-Standard Time = 4 (L_st-L_loc) + E = 4 (15- 5.98) + 2.17 = 38.25 minutes </div>
<div style="font-family: arial,sans-serif; font-size: 13px;">Hence on 21st of Dec at Solar Time = 12:00 we will have the local standard time equal to : 11:22 </div>
<div style="font-family: arial,sans-serif; font-size: 13px;">at 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? </div>
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