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<p class="MsoNormal"><font face="Arial" color="blue" size="2"><span style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">Shaojie:</span></font><o:p></o:p></p>
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<p class="MsoNormal"><font face="Arial" color="blue" size="2"><span style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">The difference between (single/multi-zone and simplified single zone) is actually the default type of air-side HVAC system used for
simulating the air-side part of a water source heat pump unit. When "single/multi-zone" is selected, the default air-side HVAC system is PVVT; When "simplified single zone" is selected, the default air-side HVAC system is "Water Loop HP". When PVVT is used,
it is capable of either serving one single zone or multi-zones with one water source heat pump unit. On the other hand, each "Water Loop HP" can only serve one single zone.</span></font><o:p></o:p></p>
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<p class="MsoNormal"><span style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">In most case, the difference in the simulation results is due to the different performance curves used for the two air-side HVAC systems. The <span class="229395215-05052009">cooling
</span>performance curves for "Water Loop HP" are normalized<span class="229395215-05052009"> (approximately)</span> at 86F entering water temperature <span class="229395215-05052009">and
</span>67<span class="229395215-05052009">F </span>entering indoor wetbulb<span class="229395215-05052009">, while the heating performance curves are normalized at </span>68F<span class="229395215-05052009"> entering water temperature and</span><span class="229395215-05052009"> <span style="FONT-SIZE: 10pt; COLOR: green; FONT-FAMILY: Arial"><font color="#0000ff">70F
entering indoor drybulb</font></span></span>, which is the ARI rating conditions for "Water Loop Heat Pump Application" of a water source heat pump unit. However, the
<span class="229395215-05052009">cooling </span>performance curves for "<span class="229395215-05052009">PVVT</span>" are normalized at <span class="229395215-05052009">77</span>F entering water temperature <span class="229395215-05052009">and
</span>67<span class="229395215-05052009">F</span><span class="229395215-05052009">
</span>entering indoor wetbulb<span class="229395215-05052009">, while the heating performance curves are normalized at </span><span class="229395215-05052009">32</span>F<span class="229395215-05052009"> entering water temperature and</span><span class="229395215-05052009"> <span style="FONT-SIZE: 10pt; COLOR: green; FONT-FAMILY: Arial"><font color="#0000ff">70F
entering indoor drybulb</font></span></span>, which is the ARI rating condition for "Ground Loop Heat Pump Application" of a water source heat pump unit. Unfortunately, in current version of eQUEST, the default EIRs for cooling and heating are the same for
both PVVT and "Water Loop HP". As a result, user has to check and modify the default EIRs <span class="229395215-05052009">(and capacities if it is specified by user)</span>with the <span class="229395215-05052009">heat pump performance data
</span>at conditions consistent with the normalization points of the performance curves (with adjustment for fan power if it is calculated separately).</span><o:p></o:p></p>
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<p class="MsoNormal"><font face="Arial" color="blue" size="2"><span style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">As an alternative, user can load all the consistent performance curves and data (e.g. EIRs and condenser pressure drop) by selecting
heat pump from heat pump library, which is an add-on feature of eQUEST and can be download at
</span></font><font face="Arial" size="2"><span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"><a href="http://www.climatemaster.com/index/equest">http://www.climatemaster.com/index/equest</a><font color="blue"><span style="COLOR: blue"> for free after registration.</span></font></span></font><o:p></o:p></p>
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<p class="MsoNormal"><font face="Arial" color="blue" size="2"><span style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">I also noticed that, if the "location set" is specified as "California (Title 24)" in eQUEST wizard when creating the simulation, an
air-side economizer is added to the water source heat pump simulated with the PVVT system, but not for the "Water Loop HP". (It does not happen when "All eQUEST Locations" is selected for "location set". In this case, there is no air-side economizer for both
PVVT and "Water Loop HP". ) It appears a bug and should be fixed. The easiest way to remove the air-side economizer from PVVT is to set the input entry of "Outside Air Control" to "Fixed Fraction" for all the heat pump units simulated with PVVT.</span></font><o:p></o:p></p>
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<p class="MsoNormal"><font face="Arial" color="blue" size="2"><span style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">Sorry for the inconvenience, I believe these issues will be addressed in the new release of eQUEST.</span></font><o:p></o:p></p>
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<p class="MsoNormal"><font face="Arial" color="blue" size="2"><span style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">Regards,</span></font><o:p></o:p></p>
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<p class="MsoNormal"><font face="Arial" color="blue" size="2"><span style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">Xiaobing</span></font></p>
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<blockquote>
<div class="OutlookMessageHeader" dir="ltr" align="left"><font face="Tahoma" size="2">-----Original Message-----<br>
<b>From:</b> bldg-sim-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org]<b>On Behalf Of
</b>eric wang<br>
<b>Sent:</b> Monday, May 04, 2009 3:49 PM<br>
<b>To:</b> bldg-sim@lists.onebuilding.org bldg-sim@lists.onebuilding.org<br>
<b>Subject:</b> [Bldg-sim] WLHP Wizard Options<br>
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<div>Hi,</div>
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<div><span style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">I try to model WLHP and find there are two options (single/multi-zone and simplified single zone) in the SD wizard if I pick water loop as heat pump source. The two models give me different
annual energy costs. If I choose the simplified single zone model, there are no cooling or heating sources under the air-side HVAC system tab. I am not sure what else makes the results different besides the heating/cooling performance curves and system types.
Any suggestions are highly appreciated.<o:p></o:p></span></div>
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<div>Thanks,</div>
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<div>Shaojie</div>
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