John<div><br></div><div>You may have already looked over what the 2.1 manual has to offer as far as explanation on this.</div><div><br></div><div>IV.71</div><div><br></div><div><div>H. Calculate the cooling part load ratio. </div>
<div><br></div><div>Some central systems control the operation of the central cooling coil based upon temperature signals from the zone thermostats (COOL-CONTROL = WARMEST). Other central systems control the operation of the central cool ing coil based upon the coil exit air temperature (COOL-CONTROL = CONSTANT, RESET, or SCHEDULED). In the latter case, the controller for the cool ing coil has a throttl ing range. As the temperature of the air leaving the coil rises and falls within the controller's throttling range, the controller varies the operation of the coil, increasing or decreasing the output of the- coil. The action of the controller must be simulated because it will have an effect on the coil surface conditions and thus also on moisture removal by the coil. Because this controller responds to the temperature of the air stream, the sensible part load ratio of the coil or unit will be calculated. This value will then be used the following hour to modify the coil exit air temperature as a function of controller set point, coil capacity, and controller throttling range (see DKTEMP algorithm description). </div>
<div><br></div><div>First, the program calculates the total and sensible cool ing equipment capacities (QCT and QCS) </div><div><br></div><div>where </div><div><br></div><div>QCT = COOLING-CAPACITY * QCMl (IV.178) </div>
<div><br></div><div><div>and </div></div><div><br></div><div>QCMl = CVAL(COOL-CAP-FT,EWB,EDB) [COOL-CAP-FT is a correction </div><div>function to the total cooling capacity to adjust for off-rated </div><div>
entering wet-bulb and entering dry-bulb temperatures] </div><div><br></div><div>and</div><div><br></div><div>QCS = COOL-SH-CAP * QCM2 {however, for direct expansion units, QCS = </div><div>(COOL-SH-CAP * QCM2) + [CONS{l) * CFM * (1.0 - CBF) * </div>
<div>(TM - 80.0)]} </div><div><br></div><div>or</div><div><br></div><div>QCS = QCT, whichever is smaller, </div><div><br></div><div>where </div><div><br></div><div>QCM2 = CVAL{COOL-SH-FT,EWB,EDB) [COOL-SH-FT is a correction function, </div>
<div>similar to QCMl, but to the sensible portion of the total </div><div>cooling capacity]. </div><div><br></div><div>The equipment cooling part load ratio (PLRC) and the sensible part load </div><div>
ratio «PASTPLRC» are then calculated,</div><div> </div><div><br></div><div>PLRC = QC/QCT </div><div><br></div><div>and</div><div><br></div><div><PASTPLRC> = QC - QCLAT / QCS </div><div><br></div><div>For direct expansion equipment, the electric power consumed by the heating </div>
<div>element in the crankcase is calculated as CRANKCASE-HEAT * (1.0 - PLRC).</div><div><br></div><div><br></div><div><br></div><br><div class="gmail_quote">2011/2/2 Nick Caton <span dir="ltr"><<a href="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div lang="EN-US" link="blue" vlink="purple">
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Hi John,</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">To answer your first question… For a DX cooling system, my
understanding is that COOL-EIR-FT’s temperatures are the outside drybulb
(at the condenser/heatpump) and the entering wetbulb temperature at the evaporator
(mixed air conditions). This mirrors how packaged equipment efficiencies/capacities
are presented in manufacturers’ literature. See attached discussion
for an example.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">I understand COOL-CAP-FT and COOL-SH-FT curves work from the same
temperatures.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">To your second question… I’m with you! </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">I’d like to see the equation for “hourly electricity
consumption” for an air-cooled DX process written out in its entirety
showing all the affecting – I was searching for something analogous to [</span>Volume
2: Dictionary<span> > </span>HVAC
Components<span> > </span>CHILLER > Chiller
Energy Consumption] <span style="font-size:11.0pt;color:#1F497D">for airside DX cooling systems a while ago and also came up
empty-handed. I have a hunch the effects of the 3 bypass curves (which are
a mystery to me) may have something to do with the hourly calculated total
capacity and/or EIR though… perhaps those need to work their way into
your equation? </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Regarding the hourly results you’re using to check your
work… I’m not sure whether those are the correct figures to work
from, but I’d caution to be mindful of the wonky effects of altitude on
calculated capacities/airflows when working with hourly outputs – recent discussion
on the list brought more to light on this topic – and the effects are
more pervasive than I originally thought…</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">~Nick</span></p>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><img width="119" height="37" src="cid:image001.jpg@01CBC2DC.E74789D0" alt="cid:489575314@22072009-0ABB"></span><b><span style="font-size:11.0pt;color:#2D4D5E"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;color:#2D4D5E"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;color:#2D4D5E">NICK CATON, E.I.T.</span></b><b><span style="color:#2D4D5E"></span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:#CC9900">PROJECT ENGINEER</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">Smith & Boucher Engineers</span><span style="font-size:7.5pt;color:#CC9900"></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">25501 west valley parkway</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">olathe ks 66061</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">direct 913 344.0036</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">fax 913 345.0617</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><a href="http://www.smithboucher.com" title="blocked::www.smithboucher.com" target="_blank"><span style="font-size:10.0pt">www.smithboucher.com</span></a></span><u><span style="font-size:10.0pt;color:blue"> </span></u><span style="font-size:11.0pt;color:#1F497D"></span></p>
</div>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10.0pt">From:</span></b><span style="font-size:10.0pt"> <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Grando,
John<br>
<b>Sent:</b> Wednesday, February 02, 2011 12:18 PM<br>
<b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Subject:</b> [Equest-users] Curve Coefficients</span></p>
</div>
</div><div><div></div><div class="h5">
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal"><span style="font-size:10.0pt">I'm
basically trying to figure out how eQUEST comes up with the total Electric
consumption for a DX coil. I thought it was the below</span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:10.0pt"> </span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:10.0pt">Total
Capacity * Capacity Curve [T] * Total EIR * EIR Curve [T] * EIR Curve [PLR] but
it's not coming out exactly the same. Does anyone have any input for what
I'm missing. The attached .xls is an example for one day. The total
capacity is 79.983 kBTU/Hr and the EIR is 0.2722.</span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:10.0pt"> </span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:10.0pt"> </span></p>
</div>
<div>
<p class="MsoNormal"><span> </span><span style="font-size:10.0pt"></span></p>
</div>
<div style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><b><span style="font-size:10.0pt;color:blue">John Grando</span></b><b><span style="font-size:10.0pt;color:black"> </span></b><b><span style="font-size:10.0pt;color:blue">LEED AP</span></b><b><span style="font-size:10.0pt;color:black">| </span></b><b><span style="font-size:10.0pt;color:gray">Mechanical
Engineer<br>
</span></b><span style="font-size:10.0pt;color:gray">Phone: 212-615-3705 | Fax: 212-615-3700<br>
</span><span style="font-size:10.0pt;color:blue"><a href="mailto:jgrando@cosentini.com" target="_blank">jgrando@cosentini.com</a><br>
<br>
</span><b><span style="font-size:10.0pt;color:gray">Cosentini Associates - A Tetra Tech Company<br>
</span></b><span style="font-size:10.0pt;color:gray">Two Pennsylvania Plaza - Third Floor - New York, NY 10121<br>
</span><span style="font-size:10.0pt;color:blue"><a href="http://www.cosentini.com/" target="_blank">www.cosentini.com</a></span><span style="font-size:10.0pt"></span></p>
</div>
<div>
<p class="MsoNormal"><span> </span><span style="font-size:10.0pt"></span></p>
</div>
<div>
<p class="MsoNormal"><span> </span><span style="font-size:10.0pt"></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:10.0pt"> </span></p>
</div>
<p class="MsoNormal"><br clear="all">
NOTICE OF CONFIDENTIALITY This E-mail message and its attachments (if any) are
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and the attachments (if any) may contain information that is confidential,
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<div style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 1.0pt 0in">
<p class="MsoNormal" style="border:none;padding:0in"><u><span style="font-size:10.0pt;color:blue"><span style="text-decoration:none"> </span></span></u></p>
</div>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
</div></div><p class="MsoNormal"><b><span style="font-size:10.0pt">From:</span></b><span style="font-size:10.0pt"> <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Grando,
John<br>
<b>Sent:</b> Wednesday, February 02, 2011 7:55 AM<br>
<b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Subject:</b> [Equest-users] Curve Coefficients</span></p><div class="im">
<p class="MsoNormal"> </p>
<p class="MsoNormal"><span style="font-size:10.0pt">Hello,</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt"> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt">For
the curve COOL-EIR-FT the two inputs for a water loop heat pump system are
"entering wetbulb temperature" and "entering water
temperature". I understand that the water temperature is the
condenser water, but is the entering wetbulb temperature for the evaporator
side?</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt"> </span></p>
<p class="MsoNormal"><span> </span><span style="font-size:10.0pt"></span></p>
</div><p class="MsoNormal"><b><span style="font-size:10.0pt;color:blue">John Grando</span></b><b><span style="font-size:10.0pt;color:black"> </span></b><b><span style="font-size:10.0pt;color:blue">LEED AP</span></b><b><span style="font-size:10.0pt;color:black">| </span></b><b><span style="font-size:10.0pt;color:gray">Mechanical
Engineer</span></b><span style="font-size:10.0pt"></span></p>
<p class="MsoNormal"><span> </span><span style="font-size:10.0pt"></span></p>
<p class="MsoNormal"><span> </span><span style="font-size:10.0pt"></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt"> </span></p>
<p class="MsoNormal"><br clear="all"></p><div class="im">
NOTICE OF CONFIDENTIALITY This E-mail message and its attachments (if any) are
intended solely for the use of the addressees hereof. In addition, this message
and the attachments (if any) may contain information that is confidential,
privileged and exempt from disclosure under applicable law. If you are not the
intended recipient of this message, you are prohibited from reading,
disclosing, reproducing, distributing, disseminating or otherwise using this
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is not intended to waive any right or privilege. If you have received this
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<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
</div>
</div>
<br><br>---------- Forwarded message ----------<br>From: "Nick Caton" <<a href="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>><br>To: "John T. Forester" <JohnTF@BVHis.com>, <<a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a>><br>
Date: Wed, 19 Jan 2011 17:43:56 -0600<br>Subject: RE: [Equest-users] Air-Cooled EIR Curves<br>
<div lang="EN-US" link="blue" vlink="purple">
<div>
<p class="MsoNormal"><span style="color:#1F497D">Hi John,</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">Hmm… intuitively I think this
makes sense, but I haven’t actually gone through creating a set of custom packaged
DX curves before – lets’ first verify we’re looking at the same definition:</span></p>
<p class="MsoNormal">Volume
2: Dictionary<span> > </span>HVAC
Components<span> > </span>SYSTEM<span> > </span>Cooling Equipment<span> > </span>DX Cooling</p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Times New Roman","serif"">COOL-EIR-FT</span></b></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Takes the U-name
of a bi-linear or bi-quadratic curve that describes the Electric Input Ratio
for cooling <u>as a function of entering wet-bulb temperature and outdoor
dry-bulb temperature (for direct expansion coils)</u> or entering wet-bulb
temperature and entering water temperature for a Water Loop Heat Pump (HP)
system. At ARI conditions, the value of the curve should be 1.</span></p>
<p class="MsoNormal"><span style="color:#1F497D">I’m pretty sure the entering
wet-bulb is that found entering the evaporator coil – the mixed air about to be
conditioned. If you check out a typical set of packaged DX unit performance
tables (If you want a specific example to follow along, I’ve just cracked open an
<a href="http://tech.lennoxintl.com/C03e7o14l/HS7CbNGGFw/ehb_lgh_abox_1010.pdf" target="_blank">engineering
guide for the Lennox LGH series</a>* to page 21), you’ll find they’ve got OA DB
along one axis (85/95/105/115) and Entering WB along the other axis
(63/67/71). It would appear the same tables could also be used to reference
data for COOL-CAP-FT and COOL-SH-CAP curves.</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">Make sense now?</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">‾Nick</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">*Disclaimer: I have no particular
ties or intent/business to advocate Lennox over their competitors – all of
their major competitors publish similar reference/sizing tables, and this
particular unit’s guide just happened to be near the top of my reference stack.</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<div>
<p class="MsoNormal"><span style="color:#1F497D"><img border="0" width="119" height="37" src="cid:image001.jpg@01CBB7FA.CA2EE8D0" alt="cid:489575314@22072009-0ABB"></span><b><span style="color:#2D4D5E"></span></b></p>
<p class="MsoNormal"><b><span style="color:#2D4D5E"> </span></b></p>
<p class="MsoNormal"><b><span style="color:#2D4D5E">NICK CATON, E.I.T.</span></b><b><span style="font-size:12.0pt;color:#2D4D5E"></span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:#CC9900">PROJECT ENGINEER</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">Smith &
Boucher Engineers</span><span style="font-size:7.5pt;font-family:"Times New Roman","serif";color:#CC9900"></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">25501 west
valley parkway</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">olathe ks 66061</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">direct 913
344.0036</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">fax 913
345.0617</span></p>
<p class="MsoNormal"><span style="color:#1F497D"><a href="http://www.smithboucher.com" title="blocked::www.smithboucher.com" target="_blank"><span style="font-size:10.0pt">www.smithboucher.com</span></a></span><u><span style="font-size:10.0pt;color:blue"> </span></u><span style="color:#1F497D"></span></p>
</div>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10.0pt">From:</span></b><span style="font-size:10.0pt">
<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>John T.
Forester<br>
<b>Sent:</b> Wednesday, January 19, 2011 4:50 PM<br>
<b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Subject:</b> [Equest-users] Air-Cooled EIR Curves</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Quick question,</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">When creating custom EIR fT and EIR fPLR curves for
air-cooled packaged DX units with digital scroll compressors, what are the two
independent variables? The DOE2 help says to use entering wet-bulb and
outside air dry-bulb. Where is the entering wet-bulb temperature
measured? Intuitively, this doesn’t seem correct to me.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Thanks,</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">John</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:gray">John T. Forester, P.E., LEED AP, Mechanical Design Engineer </span><b><span style="font-size:10.0pt;color:#0000A0">I BVH
Integrated Services I</span></b><b><span style="font-size:10.0pt;color:black"> </span></b><span style="font-size:10.0pt;color:gray">617.658.9008 tel </span><b><span style="font-size:10.0pt;color:#0000A0">I</span></b><b><span style="font-size:10.0pt;color:gray"> </span></b><span style="font-size:10.0pt;color:gray">617.244.3753
fax</span><span style="font-size:10.0pt;color:#0000A0"> <b>I</b></span><b><span style="font-size:10.0pt;color:gray"> </span></b><span style="font-size:10.0pt;color:gray">One Gateway
Center Suite 506, Newton MA 02458 </span><b><span style="font-size:10.0pt;color:#0000A0">I <a href="http://www.bvhis.com" target="_blank">www.bvhis.com</a> I
Hartford ● New Haven ● Boston</span></b><span style="font-size:10.0pt"></span></p>
<p class="MsoNormal"> </p>
</div>
</div>
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