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<p><Also, I was familiar with the 1D IAM datafile format for a collector that follows the zenith/altitude angle of the sun, but I am unfamiliar with how to setup a 2D IAM file for such a collector. The default proforma for the type1288 component references a sample 2D IAM file, so I assume 2D is applicable and 1D is not. If the collector will track the altitude angle automatically, why do I need a 2D IAM datafile?></p>
<p>There are three TESS models that incoporate the test results from the EN12975-2 collector standard.</p>
<p>Type 1288 takes a 2-D IAM file based on the longitudinal and transverse angles</p>
<p>Type 1289 takes a 1-D IAM file based on the incidence angle for beam radiation</p>
<p>Type 1290 takes the b0 and b1 parameters popularized by ASHRAE for the 1-D IAM calculations based on the incidence angle of beam radiation</p>
<p> </p>
<p>To answer your question about why you would need 2-D IAMs, it's the most rigorous of all the solutions - by far. The collector you are studying may track the altitude angle automatically but another collector may not track at all. Or the user may want to study the impact of imperfect tracking, or limitations in the tracking angles. The other reason is much simpler - many collector tests report 2-D IAMs for tracking collectors based on the longitudinal and transverse angles. That's why there are three version (88,89,90), differing only in IAM. Just there to give the user an option corresponding to the information he/she may have available.</p>
<p> </p>
<p>Jeff</p>
<p> </p>
<p>Jeff Thornton</p>
<p>President - TESS</p>
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