<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2800.1400" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=251270821-28042004>David,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=251270821-28042004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=251270821-28042004>We've
run into this as well. One issue that is relatively common with simulated
VAV systems is that the economizer operation and the VAV box operation can be
completely independent of each other, even if you don't want them to be.
This may or might not be an issue in an actual system depending on how the
controls are configured. Even if the design flow of outside air is
sufficient to cool a zone, the reduced flow at some level of
VAV turndown may not be sufficient. For this reason, there are hours
of the year (typically cooler periods) when a constant volume unit may show less
simulated cooling energy. </SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=251270821-28042004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=251270821-28042004>One
solution to this is to schedule increased levels of outside air during cooler
months, perhaps in the morning. The solution depends on when the cooling
load is not being met by outside air alone. </SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=251270821-28042004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=251270821-28042004>You
can also set the priorities of air flow and temperature reset. Varying
these will impact the trade off between fan energy and cooling
energy.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=251270821-28042004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=251270821-28042004>Good
luck.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=251270821-28042004></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=251270821-28042004>
<P><FONT size=2>_______________________</FONT></P>
<P><FONT size=2>Pat Bailey, P.E.<BR>Principal<BR>GeoPraxis, Inc<BR>205 Keller
Street<BR>Petaluma, CA 94952<BR><BR>www.geopraxis.com<BR>707.766.7010
(v)<BR>707.766.7014 (f)</FONT> </P></SPAN></FONT></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> postman@gard.com
[mailto:]<B>On Behalf Of </B>David Lanceta<BR><B>Sent:</B> Wednesday, April
28, 2004 11:35 AM<BR><B>To:</B> BLDG-SIM@GARD.COM<BR><B>Subject:</B>
[BLDG-SIM] eQUEST/economizer<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>Hi everybody!</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>First of all, I would like to say thank you to
everybody that have helped me in the past, I used to send emails to everyone
but I´m sure I´ve forgotten some of them.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>I´m simulating an office building with eQUEST,
and I´m trying to know how much energy can be saved up. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>The HVAC system type is "Standard VAV with HW
Reheat" for all the zones, the cold deck reset is 55ºF. I´ve also set up a
drybulb temperature economizer, high limit 65ºF.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I think that when the drybulb
exterior temperature is below 55ºF there should be free-cooling,
but checking the temperature values this only happens when it´s under
49ºF </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>does anybody know why it could be?</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>thanks</FONT></DIV>
<DIV><FONT face=Arial size=2>=================================<BR>David
Lanceta <BR>Área de Mecánica de Fluidos<BR>Centro Politécnico
Superior<BR>Universidad de Zaragoza<BR>María de Luna 3, tel (0034)9761000 ext
5044<BR>50015 ZARAGOZA<BR>ESPAÑA<BR></FONT></DIV><PRE>
==================
You received this e-mail because you are subscribed
to the BLDG-SIM@GARD.COM mailing list. To unsubscribe
from this mailing list send a blank message to
BLDG-SIM-UNSUBSCRIBE@GARD.COM
</PRE></BLOCKQUOTE><PRE>
===========================
You received this e-mail because you are subscribed
to the BLDG-SIM@GARD.COM mailing list. To unsubscribe
from this mailing list send a blank message to
BLDG-SIM-UNSUBSCRIBE@GARD.COM
</PRE></BODY></HTML>