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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Hi Mohannad,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>Did you check your
orientations? A surface to the north is 180 degrees (check it in type 16)
(instead of 0 degrees)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Regards,<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Mariėlle Nuchelmans</span></font><font
size=1 face=Arial><span style='font-size:8.0pt;font-family:Arial'><o:p></o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>Van:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Sabine Jansen -
BK [mailto:S.C.Jansen@tudelft.nl] <br>
<b><span style='font-weight:bold'>Verzonden:</span></b> vrijdag 2 april 2010
10:26<br>
<b><span style='font-weight:bold'>Aan:</span></b> Mohannad Bayoumi;
trnsys-users@cae.wisc.edu<br>
<b><span style='font-weight:bold'>Onderwerp:</span></b> Re: [TRNSYS-users]
Higher cooling demand in the north zone! - QVENT andQCOOL</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div id=idOWAReplyText16695>
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<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Hello Mohannad,</span></font><font
color=black><span style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Just to make sure, you didn’t mean the <strong><b><font
face=Arial><span style='font-family:Arial'>latitude</span></font></b></strong> is
MINUS 24.65 (so on the southern hemisphere, in which case the sun will come
from the north)?</span></font><font color=black><span style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Otherwise, your latitude is around the
latitude of the tropic of cancer. This is a special location and what I would
do is plot the solar radiation per m2 per orientation just to check if
then you understand. You can also leave out the solar radiation first, to
check if this is really the cause. </span></font><font color=black><span
style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
<p class=MsoNormal><strong><b><font size=2 color=black face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:black'>Qvent is defined as (see
manual): QVENT sensible ventilation energy <u>gain</u> of zone</span></font><o:p></o:p></b></strong></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>So that negative values are given if
there are ventilation outputs, i.e. LOSSES. This should only occur of your
ventilation air is a lower temperature than you indoor air.</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
<p class=MsoNormal><strong><b><font size=2 color=black face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:black'>Qcool is defined as:
QCOOL sensible <u>cooling</u> demand of zone (<u>positive values) </u></span></font><o:p></o:p></b></strong></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>This means POSITIVE values are given for
energy outputs (so this is an opposite definition of Qvent) </span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Qcool can be positive while Qvent is
negative, when solar or internal gains are bigger than the total losses and
thus additional cooling is required.</span></font><font color=black><span
style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Qcool refers to the cooling demand of your
zone that is needed according to the energy balance of your zone (and your
setpoints). If you use external air at external air temperature (and no other
cooling items, such as a cooling floor), Qcool is your total cooling demand. </span></font><font
color=black><span style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>However, if you use ventilation air at a
temperature different from Toutside, this means additional cooling is required
to produce the air at this temperature. I think in that case you need to
calculate the energy required for cooling down the air (from Toutside to Tair-inlet)
in order to come to the total cooling demand. Qvent is in this case not related
to the cooling demand, only to the energy balance of the zone.</span></font><font
color=black><span style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>I hope this is of any help.</span></font><font
color=black><span style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Kind regards, Sabine Jansen</span></font><font
color=black><span style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>p.s. The energy balance of the zone is
given in balance output 4, but in the manual there is one small error in the
definition of Qtrans, which should be defined in the opposite way, that is, it
is also included as a GAIN in the balance equation, meaning positive values are
gains to the zone and negative values are losses.</span></font><font
color=black><span style='color:black'><o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-bottom:10.0pt'><font size=3 color=black
face="Times New Roman"><span style='font-size:12.0pt;color:black'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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face="Times New Roman"><span style='font-size:12.0pt'>
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<p class=MsoNormal style='margin-bottom:12.0pt'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>Van:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Mohannad
Bayoumi [mailto:mohannad.b@gmail.com]<br>
<b><span style='font-weight:bold'>Verzonden:</span></b> do 1-4-2010 23:46<br>
<b><span style='font-weight:bold'>Aan:</span></b> trnsys-users@cae.wisc.edu<br>
<b><span style='font-weight:bold'>Onderwerp:</span></b> [TRNSYS-users] Higher
cooling demand in the north zone! - QVENT andQCOOL</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Hello, <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I am simulating the energy demand for a floor in an office building -
Lat 24.65°. <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>The floor has 4 main zones facing the 4 different orientations.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>U-Outwall: 0.15 Wh/m2.K<o:p></o:p></span></font></p>
</div>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>U-Glass: 0.5 Wh/m2.K<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>G-Glass: 56 %<o:p></o:p></span></font></p>
</div>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>External shading factor: 88%<o:p></o:p></span></font></p>
</div>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I keep getting a higher cooling demand (QCOOL) for the northern zone
against the eastern and the western ones. I tried many times with and
without inner loads and shading devices. I also tried with mechanical
ventilation - <st1:metricconverter ProductID="18°C" w:st="on">18°C</st1:metricconverter>
temperature of supplied air and 0.2 h^-1 Leaking.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>1- What can be the reason for these surprising results?<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I still can not understand why the QVENT values are in negative while
the QCOOL are in positive, although the cooling process is to lead the heat
away from the body or the space. <o:p></o:p></span></font></p>
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<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>2- If I would like to find out the total cooling demand of a zone,
should I use the QCOOL or QVENT values, or should I add them together?? <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Thank you<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Mohannad Bayoumi<o:p></o:p></span></font></p>
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