<div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:large;color:#0000ff">Dear Kyle,</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:large;color:#0000ff">I've got DX coil part load curves well figured out, but don't model chillers very often, so they haven't got much attention from me. That said, and assuming the chiller curves work consistently with the approach used for DX coils, I think...</div><div class="gmail_default" style=""><ul style=""><li style=""><font color="#0000ff" face="tahoma, sans-serif" size="4">Chilled water flow should be assumed at the AHRI test condition for all curve derivations.</font></li><li style=""><font color="#0000ff" face="tahoma, sans-serif" size="4">The curves don't pay attention to the returning / entering water temp, only the leaving / supply water temp.</font></li><ul><li style=""><font color="#0000ff" face="tahoma, sans-serif" size="4">Capacity as f(T) looks at leaving CH water temp and entering condenser water temp</font></li><li style=""><font color="#0000ff" face="tahoma, sans-serif" size="4">EIR as f(T) uses the same temps as above</font></li><li style=""><font color="#0000ff" face="tahoma, sans-serif" size="4">EIR as f(PLR) only looks at the ratio of current load vs rated capacity</font></li><li style=""><font color="#0000ff" face="tahoma, sans-serif" size="4">You have no control over the entering / return CHW temp. "It is what it is" based on load and leaving water temperature control.</font></li></ul><li><font color="#0000ff" face="tahoma, sans-serif" size="4">CHW flow rate (assuming a variable flow pump) normally varies with load, not water temp. </font></li></ul><div><font color="#0000ff" face="tahoma, sans-serif" size="4">I hope that is helpful.</font></div><font color="#0000ff" face="tahoma, sans-serif" size="4"><br></font></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Mar 8, 2017 at 10:34 AM, Kyle Fridgen via Bldg-sim <span dir="ltr"><<a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal">Hi Modellers,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">In EnergyPlus, we are attempting to model the part load performance of an air cooled chiller by generating custom performance curves using the E+ HVAC curve fit tool. We are unsure exactly what performance data to request from the manufacturer
to do so.<u></u><u></u></p>
<p class="MsoNormal"><u></u><u></u></p>
<p class="MsoNormal">For the biquadratic CAP_FT and EIR_FT, we plan to request data at various Leaving CHW Temperature (say 44-54°F) and Outdoor Air Dry Bulb Temperatures (~55-105°F). However, to define the load on the chiller at these points, we need to specify
more information.<u></u><u></u></p>
<p class="m_5688809602368954041MsoListParagraph"><u></u><span style="font-family:Symbol"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><u></u>Should CHW flow rate be held constant at 2.4 GPM/ton (AHRI)?<u></u><u></u></p>
<p class="m_5688809602368954041MsoListParagraph"><u></u><span style="font-family:Symbol"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><u></u>Should Entering CHW Temperature be held constant (~54°F)? I imagine not because there would be no Delta T when you reset leaving CHW Temperature up higher. So, should the CHW delta T be held constant instead?
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">For the quadratic EIR_FPLR, at 100% load, the ratings would be at AHRI conditions: 2.4 GPM/ton, 54/44°F Entering/Leaving Chilled Water Temperature, 95°F Outdoor Air Dry Bulb Temperature. For part load ratios:<u></u><u></u></p>
<p class="m_5688809602368954041MsoListParagraph"><u></u><span style="font-family:Symbol"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><u></u>Should CHW flow rate be varied with a fixed Entering CHW Temperature? Or vice-versa?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">We would appreciate insight from anyone who has run into this before!<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Thanks,<u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Kyle<u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><p><span style="font-size:10pt;font-family:Arial,sans-serif;color:black;background-image:initial;background-repeat:initial"></span></p>James V Dirkes II, PE, BEMP, LEED AP<br>CEO/President<br>The Building Performance Team Inc.<br>1631 Acacia Dr, GR, Mi 49504<br><br>Direct / Mobile: 616.450.8653<br><a href="mailto:jim@buildingperformanceteam.com" target="_blank">jim@buildingperformanceteam.com</a><br><br><a href="http://buildingperformanceteam.com" target="_blank">Website </a>l <a href="https://www.linkedin.com/pub/jim-dirkes/7/444/413" target="_blank">LinkedIn</a><p align="center" style="margin-bottom:0in;margin-bottom:.0001pt;text-align:center"><b><i><span style="font-size:14.0pt;line-height:115%;font-family:"MS Reference Sans Serif","sans-serif""> </span></i></b><span style="font-family:"MS Reference Sans Serif","sans-serif""></span></p><p style="vertical-align:middle">
</p><p style="margin-bottom:6.0pt;text-autospace:none"><span style="font-family:Calibri,sans-serif"><font size="4" color="#0000ff"></font></span></p><pre style="white-space:pre-wrap"><p style="margin-bottom:6.0pt;text-autospace:none"><font face="Calibri, sans-serif"><span style="font-size:13.3333px"><b>Coffee cup conversation:</b>
</span></font><span style="font-size:13.3333px;font-family:Calibri,sans-serif">Our friends, our company, our culture, our country, ourselves are not renewed once and for all. They are renewed every day.</span></p></pre></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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