<div>
<div>Hi Ery,</div>
<div> </div>
<div>I think illumination value can't be calculated from radiation data. Different skymodel and altitude of the sun provide different efficacy.</div>
<div> </div>
<div>Thanks,</div>
<div> </div>
<div>Eddy Santosa</div>
<div> </div>
<div> </div><br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Date: Mon, 6 Apr 2009 16:27:14 -0600<br>From: Ery Djunaedy <<a href="mailto:erydjunaedy@gmail.com">erydjunaedy@gmail.com</a>><br>
Subject: [Bldg-sim] illuminance data in TMY2 file<br>To: <a href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a>,<br> <a href="mailto:radiance-general@radiance-online.org">radiance-general@radiance-online.org</a><br>
Message-ID:<br> <<a href="mailto:a590350904061527v7bc912e8sc0b7334daeaaeeaa@mail.gmail.com">a590350904061527v7bc912e8sc0b7334daeaaeeaa@mail.gmail.com</a>><br>Content-Type: text/plain; charset="iso-8859-1"<br>
<br>All,<br><br>Attached is the illuminance (global horizontal) for Boise, ID, from<br>TMY2 data. Note the valley in the graph on the left bottom corner<br>which is caused by the very low illuminance values for January (the<br>
values are in the hundreds, compared to tens of thousand in February).<br>I know for a fact that in Boise January is not (much) darker than<br>December or February.<br><br>Furthermore, the corresponding radiation data do not have that dip in<br>
January. The illumination values are calculated based on the radiation<br>data, right? So if there is nothing wrong in the radiation data, is<br>this related to the model used in converting radiation data into<br>illumination values?<br>
<br>I also checked another site in Idaho, it has the same dark January.<br><br>Any thoughts?<br><br>Thanks,<br><br>Ery<br>-------------- next part --------------<br>A non-text attachment was scrubbed...<br>Name: BoiseIlluminance.jpg<br>
Type: image/jpeg<br>Size: 93828 bytes<br>Desc: not available<br>URL: <a href="http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20090406/1c2d5184/attachment-0001.jpg">http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20090406/1c2d5184/attachment-0001.jpg</a><br>
<br>------------------------------<br></blockquote></div>