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<div>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'>My
understanding is that if you assign multiple zones to a PVVT, it is modeled as
a single central water-cooled DX cooling/heating coil serving multiple
zones. One zone is designated as the control zone and the central coil is
controlled based on its thermostat. </span></font><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>According to the DOE2.2 help file: <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>“</span></font>The airflow to all other zones is
proportionate to the airflow of the control zone. In other words, the
thermostats in the non-control zones have no effect on either airflow or supply
air temperature. They may, however, modulate a reheat coil or baseboard.”
<o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'>Thus,
there may be times where there is simultaneous cooling and heating for some
zones. The only way to have one compressor per zone is to assign each zone to
its own SYSTEM.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'>For
the HP system type, when multiple zones are assigned to a single SYSTEM, each
zone is modeled as having its own compressor and DX heating/cooling coil.
This eliminates simultaneous heating and cooling. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>This is all based on my review of the DOE2.2 help
file. If anyone has a different experience, I would appreciate hearing
about it.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Doug Maddox<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The Weidt Group<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>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-family:"Times New Roman"'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Xiaobing Liu<br>
<b><span style='font-weight:bold'>Sent:</span></b> Thursday, September 18, 2008
5:23 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Dan Russell;
bldg-sim@lists.onebuilding.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Bldg-sim] WLHP Loop
with Chilled Water and Geothermal WaterSources</span></font><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-family:"Times New Roman"'><o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Dan:</span></font><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-family:"Times New Roman"'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt;font-family:"Times New Roman"'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>For your simulation, I think you can model
it as a typical boiler and cooling tower system and then convert the heat
rejection and heat addition loads of WLHP loop to the required energy use
of the hot and cold water if you know the efficiency of the heat exchanger
that isolates the WLHP loop from the hot/cold water. It may be a bit more
challenging if you want to couple the chilled water system with the WLHP
system. My initial thought is that you can create a dummy zone that is cooled
by the chilled water system and has the internal load identical with the heat
rejection load of the WLHP. You may have to run the simulation twice and
manually input the internal load to the dummy zone. Why don't you use cooling
tower to cool the WLHP water? Cooling tower should be cheaper to run than the
chiller.</span></font><font size=3 face="Times New Roman"><span
style='font-size:12.0pt;font-family:"Times New Roman"'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt;font-family:"Times New Roman"'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Regarding eQUEST using PVVT to represent
air-side of WLHP (water-to-air heat pump), the reason is PVVT has more
flexibility to model packaged DX coil unit. By specifying stages of cooling and
heating capacity, minimum airflow ratio, and applying proper performance
curves, PVVT can model either conventional heat pump with single stage
compressor and constant speed fan, or more advanced heat pump with
two-stage compressor and variable speed fan. In addition, with PVVT, you
can simulate a DOAS that heats and/or cools the OA with a water-to-air heat
pump after OA is preconditioned with ERV.</span></font><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-family:"Times New Roman"'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt;font-family:"Times New Roman"'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Hope it helps,</span></font><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-family:"Times New Roman"'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt;font-family:"Times New Roman"'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>Xiaobing</span></font><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-family:"Times New Roman"'><o:p></o:p></span></font></p>
</div>
<blockquote style='margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>-----Original Message-----<br>
<b><span style='font-weight:bold'>From:</span></b>
bldg-sim-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org]<b><span
style='font-weight:bold'>On Behalf Of </span></b>Dan Russell<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, September 16, 2008
11:43 AM<br>
<b><span style='font-weight:bold'>To:</span></b> bldg-sim@lists.onebuilding.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [Bldg-sim] WLHP Loop with
Chilled Water and Geothermal Water Sources</span></font><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-family:"Times New Roman"'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'>I
have a building that is predominantly VAV with UFAD using a boiler/chiller
plant. However, one portion of the building is residential which we would
like to use WLHP’s for. I would like to use purchased hot water
(geothermal at 110 deg from City) and the chilled water from the building plant
to maintain the WLHP Loop between 60 and 90 deg. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'>Any
ideas on how to model this?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'>Also,
I’ve been a bit confused on how eQuest uses PVVT systems to represent the
air-side of WLHP systems. Any references or resources anyone has that
explains the theory behind this would be greatly appreciated.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'>Thanks,
<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=4 color="#a0002f" face=Cheltenham><span
style='font-size:14.0pt;font-family:Cheltenham;color:#A0002F'> </span></font><font
size=5 color="#a0002f" face=Cheltenham><span style='font-size:18.0pt;
font-family:Cheltenham;color:#A0002F'>Dan Russell, EIT <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color="#a0002f" face=Cheltenham><span
style='font-size:10.0pt;font-family:Cheltenham;color:#A0002F'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color="#a0002f" face=Cheltenham><span
style='font-size:10.0pt;font-family:Cheltenham;color:#A0002F'><img width=200
height=174 id="Picture_x005f_x0020_1" src="cid:image001.jpg@01C919D8.5DE9E610"
alt="cid:image001.jpg@01C840A4.E711B250"></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p>
</blockquote>
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