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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>I had a question about calculating baseline 90.1 efficiency for electric DWHs (tank type).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Based on Table 7.8, my efficiency needs to be SL = 20 + 35*sqrt(V) at a 70 degree delta T between water and ambient, where SL is the standby loss in btuh, and V is the volume of the tank.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>If, in my proposed model, I have a 240 gallon tank (meaning my baseline has the same volume), it would appear that the maximum standby loss at a 70 degree delta should be 562 btuh [20 + 35 * sqrt(240)]<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Since eQuest calculates the heat loss by multiplying the UA (thermal conductivity of storage tank) by the tank, it would appear that my UA for this particular example would be 562 / (70*240), or 0.0334.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>That way, at a 70 degree delta, the heat loss (SL) would be 0.0334 Btu/hr-gal-F * 240 gallons * 70 F = 562 btuh<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Does that sound about right? <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks to anyone that has a quick chance to review!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b><span style='font-family:"Arial","sans-serif";color:teal'>GHT Limited<br></span></b><b><span style='font-family:"Arial","sans-serif"'><ns0:PersonName><span style='color:black'>James Hansen</span></ns0:PersonName></span></b><b><span style='color:black'>, PE, LEED AP<o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>Senior Associate</span></b><b><span style='color:black'><o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'><ns0:Street><ns0:address><span style='color:black'>1010 N. Glebe Rd, Suite 200</span></ns0:address></ns0:Street></span><o:p></o:p></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'><ns0:place><ns0:City><span style='color:black'>Arlington</span></ns0:City><span style='color:black'>, </span><ns0:State><span style='color:black'>VA</span></ns0:State><span style='color:black'> </span><ns0:PostalCode><span style='color:black'>22201-4749</span></ns0:PostalCode></ns0:place></span><span style='color:black'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:black'>703-338-5754 (Cell)</span><span style='color:black'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:black'>703-243-1200 (Office)</span><span style='color:black'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:black'>703-276-1376 (Fax)</span><span style='color:black'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:teal'><a href="http://www.ghtltd.com/"><span style='font-size:10.0pt;color:blue'>www.ghtltd.com</span></a><o:p></o:p></span></p><p class=MsoNormal><b><span style='color:#31849B'><o:p> </o:p></span></b></p><p class=MsoNormal><o:p> </o:p></p></div><P align=left><FONT size=2><FONT face=Tahoma><FONT color=#0000ff>
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