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<p class=MsoNormal><span style='color:#404040'>Ana, <o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#404040'>As I read the help files, I
believe you are correct that you need to develop only one set of curves which
governs the equipment operation for both heating and cooling. I’ve not
developed custom curves for this chiller type, but I have a couple thoughts
that might be helpful.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#404040'>One suggestion is to dig into
the hourly chiller reports. I think you will see a set of variables with the
phrase “chiller/heater only” in the variable name.( I say “I
think” because I recently looked at the reports for a “Heat Pump”
chiller (not a “Loop to Loop Heat Pump” Chiller.))<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#404040'>These variables seem to report
on the heating mode operation of the “chiller.” One is titled, “Electric
Heat Use, Heater/Chiller only.” I am not clear what “Electric Heat
Use” would represent: I think this is likely the kW power consumption in
heating mode operation?<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#404040'>Hopefully, there is also a
report variable which tells you what “mode” the equipment is
operating at – there are 4 modes of operation as described in the eQuest
help for “Loop-to-Loop” chiller type<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#404040'>You can calculate and spot check
the kW/ton that the chiller is operating at, by digging into these reports and
doing some calculations on the data. There are also report variables which show
the what eQuest calculated for the adjusted EIR, so you can check against what
you think it should be from your curve coefficients.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#404040'>Another thought is to examine
the default curves provided for the “Loop to Loop Heat Pump” in
eQuest. Pull the coefficients from the performance curve properties and graph
them in excel (fix one of the variable so you can do it in 2D.) Doing some
comparisons with your curves might help you figure out the situation.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#404040'>One thing I’ve noticed
when looping into this is the variable “MIN-COND-T” (in eQuest
under Chiller Properties: Condenser tab.) In cooling mode operation this seems
to limit the minimum condenser temp – check the hourly report on “Condenser
entering temperature”. For a ground loop HX system, the default value (of
70 F) seems high, since the ground source loop would often be below this temp.
I’m unsure how to interpret this –it’s something I’ve
noticed but not delved into.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:#404040'>Regards,<o:p></o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;color:#404040'><o:p> </o:p></span></p>
<p class=MsoNormal><b><span style='font-size:11.0pt;color:#28AAE1'>Molly Curtz</span></b><b><span
style='font-size:11.0pt;color:#28AAE1'><o:p></o:p></span></b></p>
<p class=MsoNormal style='text-align:justify'><span style='font-size:10.0pt;
color:#595959'>Mechanical Engineer<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:justify;text-indent:.5in'><span
style='font-size:10.0pt;color:#595959'><o:p> </o:p></span></p>
<p class=MsoNormal style='text-align:justify'><b><span style='font-size:11.0pt;
color:#595959'>Arup<o:p></o:p></span></b></p>
<p class=MsoNormal style='text-align:justify'><span style='font-size:10.0pt;
color:#595959'>403 Columbia Street Suite 220 Seattle WA 98104<o:p></o:p></span></p>
<p class=MsoNormal style='text-align:justify'><b><span style='font-size:10.0pt;
color:#595959'>t</span></b><span style='font-size:10.0pt;color:#595959'> +1 206
749 9674 <b>d</b> +1 206 493 2234 <o:p></o:p></span></p>
<p class=MsoNormal style='text-align:justify'><b><span style='font-size:10.0pt;
color:#595959'>f</span></b><span style='font-size:10.0pt;color:#595959'> +1 206
749 0665 <b><o:p></o:p></b></span></p>
<p class=MsoNormal style='text-align:justify'><span style='font-size:10.0pt;
color:#595959'>www.arup.com<o:p></o:p></span></p>
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<p class=MsoNormal><span style='color:#404040'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> equest-users-bounces@lists.onebuilding.org
[mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Ana N.<br>
<b>Sent:</b> Thursday, September 30, 2010 6:58 AM<br>
<b>To:</b> cmg750@gmail.com<br>
<b>Cc:</b> equest-users@lists.onebuilding.org<br>
<b>Subject:</b> Re: [Equest-users] FW: Custom curves - Loop to Loop Heat Pump<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>Carol,
<br>
<br>
DOE22Vol2-Dictionary_47b, pages 220-221 indicate that only one curve should be
used. That is why I tried creating only one curve. I assume we should create
one curve EIR= t ( t evaporator leaving, t cond entering). It is
relatively simple for the cooling mode. In the heating mode, the evaporator
leaving temperature is actually the source fluid leaving temperature
(manufacturers typically provide the data for the source fluid entering
temperature), while the condenser entering temperature would be the load fluid
entering temperature (manufactures typically provide the data for the load
fluid leaving temperature). Do you agree with this rationale?
Unfortunately, I do not like much the results I got.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>DOE22Vol2-Dictionary
says that curves should be normalized at the Eurovent rating condition, rather
than ARI. </span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>Thank
you<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <br>
Ana<br>
<br>
<o:p></o:p></span></p>
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style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
<hr size=2 width="100%" align=center id=stopSpelling>
</span></div>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>Date: Wed, 29 Sep 2010 18:49:39 -0700<br>
Subject: Re: [Equest-users] FW: Custom curves - Loop to Loop Heat Pump<br>
From: cmg750@gmail.com<br>
To: ananeddav@hotmail.com<br>
CC: equest-users@lists.onebuilding.org<br>
<br>
Hi Ana,<br>
<br>
As always it would be good to see what you are looking at so if you feel
comfortable sending your .inp and .pd2 files please do. I'm not sure why the
HIR field is grayed out but I can understand why 2 HIR curves would confuse
eQUEST. You will have to do a parametric run or just run your model twice, once
with one curve and again with the other curve. Also, be sure to read the
information about curves and curve inputs in the DOE2 manual. All the data
needs to be normalized around the ARI conditions and the ARI conditions always
equal 1.0. It can be confusing at first.<br>
<br>
Good luck!<br>
<br>
Carol<o:p></o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>On
Wed, Sep 29, 2010 at 2:29 PM, Ana N. <<a href="mailto:ananeddav@hotmail.com">ananeddav@hotmail.com</a>>
wrote:<o:p></o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <br>
</span>Dear e-quest users,<span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
<br>
</span>I am modeling a central ground source heat pump that provides both
cooling and heating by using the Loop to Loop Heat Pump. I am trying to derive
the performance curves based on a very detailed set of data provided by the
manufacturer. What confuses me is that HIR field under the performance curve
tab is grayed out. <span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span> <span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span>I have derived one curve by combining the performance data for
cooling and heating mode (by using methodology described for chillers, “<a
href="http://www.taylor-engineering.com/downloads/articles/ASHRAE%20Symposium%20AC-02-9-1%20Electric%20Chiller%20Model-Hydeman.pdf"
target="_blank"><span style='color:windowtext;text-decoration:none'>Tools and
Techniques to Calibrate Electric Chiller Component Models</span></a>, ASHRAE
Symposium” ). I am not sure this is the correct approach. Should I create
one EIR curve by combining the data for cooling and heating (EIR= f(T
evaporator leaving, T cond entering) and leave HIR curve “grayed
out”?<span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span>I also run the model with two separate curves <span style='font-size:
10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span>EIR= f (T evaporator leaving, T cond entering), <span style='font-size:
10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span>HIR= f(T evaporator leaving, T cond entering),<span style='font-size:
10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span>each derived using the performance data for corresponding mode of
operation.<span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span> However, when I run the model with two different HIR curves, the
result remains unchanged as if e-quest does not use this curve at all.<span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span>At this point, I am using default EIR=f( part load). I am still using
e-quest 3-63.<span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span> <span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span>I would really appreciate sharing your experience in modeling the Loop
to Loop Heat Pump and deriving custom curves.<span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'><br>
</span> <span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span>Thank you<span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
<br>
</span>Ana<span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
</span> <span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><br>
<br clear=all>
<br>
-- <br>
Carol Gardner PE<o:p></o:p></span></p>
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