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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoPlainText>One more thought since peak load from windows was mentioned earlier: <o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>In calculating peak cooling loads for sizing equipment (using Trane TRACE), I have almost always found that the solar gains through windows were more significant than conductance gains through windows...usually about 1.5 times greater, sometimes much more. This of course depends on the U-value, SHGC, and orientation of the assemblies. Unless a building is highly internal load driven, I generally find that solar gain through windows is one of the top three driving factors in peak cooling load (including lighting, plug loads, ventilation, etc). Adding effective building shades can often result in appreciably smaller cooling equipment, potentially allowing the equipment to operate under more favorable part-load conditions as well as saving money up front.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>With that said, peak design load and annual energy are two different animals. I agree that the overall percent energy savings on an annual basis will be pretty low. Just wanted to mention this peak load side effect.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Christian <o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> equest-users-bounces@lists.onebuilding.org [mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Michael Wilson<br><b>Sent:</b> Thursday, May 31, 2012 3:03 PM<br><b>To:</b> 'Bobby Sy'; equest-users@lists.onebuilding.org<br><b>Subject:</b> Re: [Equest-users] building shade effect<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>While I wouldn’t expect big savings from the shades, I think it might be a bit higher than what you’re seeing because of the way its modelled. Using proportional transmittance doesn’t account for how the shading varies with sun angle. When the sun is high, less solar will get through. As Bill says, I would model this as a building shade, actually putting each louver in. It looks like the louvers are tubular, so you can probably approximate that with a vertical shade and another one at 45°. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>While this sounds like a lot of work, if you use copy and paste in the inp file it probably isn’t as bad as it sounds. Just need to change the z coordinate once you’ve put the first ones in. You might consider doing it in Excel, with a formula for the z, and then copying the results into the inp file. That would be pretty quick.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Mike<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><i><span lang=EN-CA style='font-size:9.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Michael Wilson, P.Eng., Enerficiency Consulting<o:p></o:p></span></i></p><p class=MsoNormal><i><span lang=EN-CA style='font-size:9.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>PO Box 1911 - 458 Abbs Rd., Gibsons, BC V0N 1V0 | 604-886-9864 | <a href="http://www.enerficiency.ca">www.enerficiency.ca</a><o:p></o:p></span></i></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <a href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a> <a href="mailto:[mailto:equest-users-bounces@lists.onebuilding.org]">[mailto:equest-users-bounces@lists.onebuilding.org]</a> <b>On Behalf Of </b>Bobby Sy<br><b>Sent:</b> May-30-12 7:19 PM<br><b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> [Equest-users] building shade effect<o:p></o:p></span></p></div><p class=MsoNormal><span lang=EN-CA><o:p> </o:p></span></p><div><p class=MsoNormal><span lang=EN-CA>Hello everyone!<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA>I am working on a project, a high rise office building. The architect added louvers as part of the design which I admire for sophistication. Attached is a picture that shows the louvers outside for shading. But, when I did the initial run, the effect of the louvers is only around 1% energy improvement from the baseline.<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA>Please let me know if there is a better way to do it in eQuest. What I did was to measure the louver thickness and proportioned it to the glass area that it covers. I put the fraction as "Transmittance:" in Building and Fixed Shades properties. Doe 2 help says: <o:p></o:p></span></p><h5><span lang=EN-CA style='color:#666600'>TRANSMITTANCE</span><span lang=EN-CA><o:p></o:p></span></h5><p class=MsoBodyText><span lang=EN-CA style='color:#666600'>Fraction of incident solar radiation that is transmitted by the shading surface. The default value is 0.0, which means the surface is opaque. A value greater than 0.0 represents a device that passes some solar radiation, such as a tree, lattice, or fabric. Using SHADE-SCHEDULE allows seasonal variation in transmittance. Daylighting calculation assumes TRANSMITTANCE = 0.</span><span lang=EN-CA><o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA>The design team quite find it hard to believe that the louvers have very minimal effect. I told them to consider the window to wall ratio (almost 60%) and that fact that they will be using a clear glass, even with these louvers partial UV rays still pass through the gaps that spreads allover the glass surface that adds to the heat load for air conditioning. Ive noticed to some of my other projects in tropical countries, building shades don't have much effect to energy efficiency. Did anyone encounter the same result with building shades? <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA>Thanks,<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA>Bob<o:p></o:p></span></p></div></div></body></html>