Kathryn,<br><br>I think that .5 cfm/sf is too low. I never saw it used when I was designing HVAC systems except for an occasionally used interior space. I immediately change it to1.0 cfm/sf which I feel is a good place to start. For highly loaded rooms with lots of internal gain I sometimes up that amount after I have checked the other possible inputs.<br>
<br>Carol<br><br><div class="gmail_quote">On Tue, Sep 7, 2010 at 1:55 PM, Kathryn Kerns <span dir="ltr"><<a href="mailto:kathryn.kerns@bceengineers.com">kathryn.kerns@bceengineers.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
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<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size: 10pt; font-family: Arial;">Everyone, </span></font></p>
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<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size: 10pt; font-family: Arial;">We are having a discussion at the office about how to define
the supply airflow and energy model baseline. I pick the baseline system type
per Appendix G (packaged single zone, packaged VAV, etc., set the heating
sizing ratio to 1.25 and the cooling sizing ratio to 1.15, leave the heating and
cooling capacities blank so the model will auto-size, and then set the default
airflow to 0.5 cfm/sqft and let eQuest run. I then check to see if the baseline
energy model unmet hours are less than 300 and are within 50 hours of the
proposed model. If the baseline energy model is above 300 unmet hours or isn’t
within 50 hours of the proposed model, I will then start tweaking the airflow
in the baseline energy model thermal blocks that are causing the unmet hour
issues to solve the problem. </span></font></p>
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<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size: 10pt; font-family: Arial;">Is this what everyone else is doing or do leave the airflow with
the default values it calculated with the 0,5 cfm/sqft limit and enter capacity
values in the previously blank HVAC cooling and heating capacities slots so the
baseline energy model stops auto-sizing? </span></font></p>
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<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size: 10pt; font-family: Arial;">Thanks.</span></font></p>
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<p style="margin: 0in 0in 0.0001pt;"><b><b><font size="3" color="black" face="Arial"><span style="font-size: 12pt; font-family: Arial; color: black;">Kathryn Kerns</span></font></b></b></p>
<p style="margin: 0in 0in 0.0001pt;"><i><b><i><font size="2" face="Arial"><span style="font-size: 11pt; font-family: Arial; font-weight: bold; font-style: normal;">Systems Specialist</span></font></i></b></i></p>
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<p style="margin: 0in 0in 0.0001pt;"><b><b><font size="1" color="black" face="Times New Roman"><span style="font-size: 9pt; color: black;">| Ph: 253.922.0446 | Fx: 253.922.0896 |</span></font></b></b><font size="1" color="black"><span style="font-size: 7pt; color: black;"> </span></font></p>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Carol Gardner PE<br>
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