In the past week I have been comparing a GSHP to a WLHP system with a cooling tower system and it seems to me that eQuest is underestimating cooling tower energy use, particularly fan energy use. Are there any resources that explain how eQuest calculates cooling tower energy use, or has anyone done tests to confirm cooling tower energy use?<br>
<br>I am concerned that the cooling tower allows the fan to operate at below 0.01% of it's design airlfow in a given hour, this means that when there are low cooling loads, the fan is allowed to short-cycle--a condition not allowed in the real world.<br>
<br>Thanks,<br><br>--<br>Karen<br><br><div class="gmail_quote">On Wed, May 14, 2008 at 9:57 AM, Adam Young <<a href="mailto:way@freese.com">way@freese.com</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
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<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">Good morning,</span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">I am having similar results with a
ground-coupled heat pump and am following this thread closely. I am only
realizing savings of about 5% to 10% over an air-source HP.</span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">I believe I am incorrectly separating out
the fan-energy on the air-source units. What is the procedure for getting the fan
and compressor energy separate on the air-source units (12 SEER air-source unit
per 90.1-2004, baseline design)? If I understand correctly, the GCHP efficiency
stated under ARI 13256 does not include external fan energy or external pump
energy, and therefore, the stated GCHP efficiency can be converted into EIR
directly. Correct? </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">Also, for the GCHP the correct number to
use is the "GLHP EER" value from the manufacturer based on ARI
13256, which is higher than the water-loop HP (WLHP) ARI EER? Is that correct?</span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">Experience tells me a GCHP should realize
more savings than what I am getting, which leads me to believe I am inputting "garbage"
into the model. Thanks for your help!</span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<div>
<p><i><b><i><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy; font-weight: bold;">Adam
Young</span></font></i></b></i><font color="navy"><span style="color: navy;"></span></font></p>
<p><font color="navy" face="Times New Roman" size="3"><span style="font-size: 12pt; color: navy;"> </span></font></p>
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<p><b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma; font-weight: bold;">From:</span></font></b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma;">
<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>] <b><span style="font-weight: bold;">On Behalf Of </span></b>Demba Ndiaye<br>
<b><span style="font-weight: bold;">Sent:</span></b> Wednesday, May 14, 2008 8:05
AM<br>
<b><span style="font-weight: bold;">To:</span></b> Tom Butler;
<a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a><br>
<b><span style="font-weight: bold;">Subject:</span></b> Re: [Bldg-sim] Space
Cooling Energy Consumption with GSHP</span></font></p>
</div><div><div></div><div class="Wj3C7c">
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">Thomas, </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">You should definitively have more savings
than that, even if there is the pump energy. </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">One first thing to check: the efficiency
of GSHP should be much higher than that of air-source heat pumps in both
heating and cooling modes. </span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<div>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">______________</span></font><font color="navy"><span style="color: navy;"></span></font></p>
<p><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">Demba
Ndiaye</span></font></p>
</div>
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<div style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">
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<p><b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma; font-weight: bold;">From:</span></font></b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma;">
<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>] <b><span style="font-weight: bold;">On Behalf Of </span></b>Tom Butler<br>
<b><span style="font-weight: bold;">Sent:</span></b> Tuesday, May 13, 2008 5:53
PM<br>
<b><span style="font-weight: bold;">To:</span></b> <a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a><br>
<b><span style="font-weight: bold;">Subject:</span></b> [Bldg-sim] Space Cooling
Energy Consumption with GSHP</span></font></p>
</div>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">I
am modeling an apartment style dormitory for a project in Atlanta, GA.
Each of the 45 units is served by its own heat pump, along with a few zones for
public areas. For an energy efficiency grant application I have compared the
designed system, a ground source heat pump, with an air source heat pump
prescribed by 90.1. Other than the systems, the models are identical. </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">The
energy use for space cooling is significantly higher for the GSHP system
(24,000 kWh vs. 17,000 kWh). Because the power required to run pumps offsets
the savings in heating energy, this destroys the rationale for spending the
extra money on the Ground Source Heat Pump, as well as our chances of receiving
the grant.</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Has
any one encountered this issue? </span></font></p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Thanks</span></font>
</p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">tb </span></font></p>
<p><b><font color="black" face="Garamond" size="3"><span style="font-size: 12pt; font-family: Garamond; color: black; font-weight: bold;">Thomas Butler,</span></font></b>
<font color="black" face="Garamond"><span style="font-family: Garamond; color: black;">LEED
AP</span></font><b><span style="font-weight: bold;"> </span></b><br>
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