<HTML><BODY>   <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d">Dear Daisy</span></p> <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d"> </span></p> <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d">assuming you have an external blind outside of your single skin facade, the single skin facade is thermally equivalent to your thermal envelope (the inner skin of the double skin facade) and the blind is the same, you will still have higher temperatures in the air gap than the ambient air temperature. Therefore, as written, I would expect higher cooling loads.</span></p> <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d"> </span></p> ! <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d">However, the double skin facade allows you to have the blind lowered in high rise buildings for more hours of the year, usually. Therefore, taking this aspect into account, the double skin facade may prove beneficial. Also, if you can close the air gap in the winter, you will have improved U-value. Again, the double skin facade may prove beneficial.</span></p> <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d"> </span></p> <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d">Best</span></p> <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d">Achim</span></p> <p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: #1f497d"> </span></p> <br /><br />--------- Original-Nachricht --------<br /> Von: "Íõ¾Õ»¨" <luckygrass100@hotmail.com><br /> An: "achim.geissler@intergga.ch" <achim.geissler@intergga.ch>, "esp-r@lists.strath.ac.uk" <esp-r@lists.strath.ac.uk><br /> Betreff: RE: [esp-r] boundary conditions for nonsymmetric constructions<br /> Datum: 29/04/10 04:31<br /> <br />  <font size="4">Dear Achim,</font><br /> <font size="4"></font> <br /> <font size="4">   I  accept that  higher cooling loads for a double skin facade as opposed to a single skin facade with external blind is normal.But I  compared cooling load in summer with external respiration double skin facade as opposed to a single skin facade! for the south wall.Because of natural ventilation by thermal pressure between the airgap and environment,it is expected that cooling load with external respiration double skin facade is smaller,Assuming they have equivalent shading effect.Right?Thank you for your answers.Daisy.</font><br /> <font size="4"></font> <br /> <font size="4"></font> <br /> <font size="4"></font> <br /> <font size="4"></font> <br /> <hr /> <br /> CC: esp-r@lists.strath.ac.uk<br />From: achim.geissler@intergga.ch<br />To: luckygrass100@hotmail.com<br />Subject: Re: [esp-r] boundary conditions for nonsymmetric constructions<br />Date: Wed, 28 Apr 2010 22:28:10 +0200<br /><br />Dear Daisy<br /> <div><br /></div> <div>higher cooling loads for a double skin facade as opposed to a single skin facade with external blind is to be expected. The facade air gap will usually have higher temperatures than ambient. Thus, conduction is increased.</div> <div><br /></div> <div>Best</div> <div>Achim</div> <div><br /> <div> <div>On Apr 28, 2010, at 4:24 PM, Íõ¾Õ»¨ wrote:</div><br /> <blockquote><span style="word-spacing: 0px; font: medium Helvetica; text-transform: none; color: #000000; text-indent: 0px; white-space: normal; letter-spacing: normal; border-collapse: separate" class="ecxApple-style-span"> <div class="ecxhmmessage" style="font-size: 10pt; font-family: Verdana"><font size="4">When I define the boundary conditions which apply to each surface in the model by selecting<span class="ecxApple-converted-space"> </span></font><font size="4"><em>check via vertex contiguity</em><span class="ecxApple-converted-space"> </span>facility.It scans the polygons of a model looking for surfaces in<br />various zones which are close matches<br />in terms of shape and position.After that,I began to take the action<span class="ecxApple-converted-space"> </span><em>simulation</em>.It warned that<span class="ecxApple-converted-space"> </span><em>Surface X has a nonsymmetric construction interior.It faces Y  which is composed of interior (which may not match).</em>Here,X and Y are surfaces matching in terms of shape and position.They are the same surface actually separating two adjacent zones.They just have opposite directions for the two zones.And<span class="ecxApple-converted-space"> </span><em>interior</em>is the name of construction defined by myself.I wonder whether the warnings affect simulation results?</font><br /><font size="4">I am simulating thermal performance of external respiration double skin facade.I built zones for airgap between the two curtain walls.But it turned out that cooling load in summer with double skin facade for south wall is bigger than cooling load with single skin facade for south wall.I can't explain this.I am thinking whether It is caused by the wrong surface connections &boundary conditions described above?</font><br /><font size="4">I am expecting your kind answers.Thank you in advance!Daisy.</font><br /><br /> <hr /> ¸ü¶àÈÈÀ±×ÊÑ¶¾¡ÔÚÐÂ°æMSNÊ×Ò³£¡<span class="ecxApple-converted-space"> </span><a href="http://cn.msn.com/">Á¢¿Ì·ÃÎÊ£¡</a><span class="ecxApple-converted-space"> </span>_______________________________________________<br />esp-r mailing list<br /><a href="mailto:esp-r@lists.strath.ac.uk">esp-r@lists.strath.ac.uk</a><br /><a href="http://lists.strath.ac.uk/mailman/listinfo/esp-r">http://lists.strath.ac.uk/mailman/listinfo/esp-r</a></div></span></blockquote></div><br /> <div><span style="word-spacing: 0px; font: 12px Helvetica; text-transform: none; color: #000000; text-indent: 0px; white-space: normal; letter-spac! ing: normal; border-collapse: separate" class="ecxApple-style-span"> <div style="word-wrap: break-word"> <div><a href="mailto:achim.geissler@intergga.ch">achim.geissler@intergga.ch</a></div> <div><br /></div> <div><br /></div></div></span><br /></div><br /></div> <br /><hr />ÁÄÌì+ËÑË÷+ÓÊÏä ÏëÒªÇáËÉ³öÓÎ,ÊÖ»úMSN°ïÄã¸ã¶¨! <a href="http://3g.msn.cn/" target="_new">Á¢¿ÌÏÂÔØ£¡</a><BR><BR>________________________________________________________________<BR>Diese Mitteilung wurde von http://www.breitband.ch uebermittelt.<BR>Einer der schnellsten Kabel-Internet Zugaenge!<BR></BODY></HTML>