<div>Hi Chris,</div>
<div> </div>
<div>CIBSE suggest to replace g with gcos(theta) in the Grasshof number. That means, it accounts for the roof being tilted in natural convection. When it comes to roofs, there is another aspects that starts to be important ... the roof finishing in tiles will have a 'detoriated' velocity underneath the tiles. It is mainly that one directing the convective losses ...</div>
<div> </div>
<div>Am I correct on this?</div>
<div> </div>
<div>Leen<br><br><br></div>
<div class="gmail_quote">On Sat, Feb 11, 2012 at 11:45 PM, Chris Yates <span dir="ltr"><<a href="mailto:chris.malcolm.yates@gmail.com">chris.malcolm.yates@gmail.com</a>></span> wrote:<br>
<blockquote style="BORDER-LEFT:#ccc 1px solid;MARGIN:0px 0px 0px 0.8ex;PADDING-LEFT:1ex" class="gmail_quote">
<p>It's true wind does dominate external convection.</p>
<p>Cibse guide A will give you all the numbers that you're looking for </p><span class="HOEnZb"><font color="#888888">
<p>Chris</p></font></span>
<div class="HOEnZb">
<div class="h5">
<div class="gmail_quote">On 11 Feb 2012 22:40, "Paul Hay" <<a href="mailto:phcjam@yahoo.com" target="_blank">phcjam@yahoo.com</a>> wrote:<br type="attribution">
<blockquote style="BORDER-LEFT:#ccc 1px solid;MARGIN:0px 0px 0px 0.8ex;PADDING-LEFT:1ex" class="gmail_quote">
<div>
<div style="FONT-FAMILY:times new roman,new york,times,serif;FONT-SIZE:12pt">
<div><span>I've only seen </span>reference values of interior convection coefficients for tilted surfaces, not exterior coefficients: which are available for summer & winter conditions, due to the difference in wind velocity.<br>
</div>
<div> </div>
<div>Paul Hay MBA, BA(Arch)<br>Managing Partner<br>PAUL HAY Capital Projects<br><br><span style="FONT-STYLE:italic">Caribbean Capital Project Management & Planning</span><br><br><img alt=""><br><br>P.O.Box 3367<br>Constant Springs, Kgn. 8<br>
Jamaica, W.I.<br><br></div>
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<div> <br></div><br><br>
<div style="FONT-FAMILY:times new roman,new york,times,serif;FONT-SIZE:12pt">
<div style="FONT-FAMILY:times new roman,new york,times,serif;FONT-SIZE:12pt">
<div dir="ltr"><font face="Arial">----- Forwarded Message -----<br><b><span style="FONT-WEIGHT:bold">From:</span></b> leen peeters <<a href="mailto:l.f.r.peeters@gmail.com" target="_blank">l.f.r.peeters@gmail.com</a>><br>
<b><span style="FONT-WEIGHT:bold">To:</span></b> <a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a> <br><b><span style="FONT-WEIGHT:bold">Sent:</span></b> Saturday, February 11, 2012 2:59 PM<br>
<b><span style="FONT-WEIGHT:bold">Subject:</span></b> [Bldg-sim] exterior convection coefficient for tilted roof<br></font></div><br>
<div>
<div>Dear,</div>
<div> </div>
<div>can anyone point me to some reference values for exterior convection coefficients for tilted surfaces like a roof?</div>
<div> </div>
<div>Thanks</div>
<div> </div>
<div>Leen</div></div><br>_______________________________________________<br>Bldg-sim mailing list<br><a href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org" target="_blank">http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org</a><br>
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