<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:p="urn:schemas-microsoft-com:office:powerpoint" xmlns:a="urn:schemas-microsoft-com:office:access" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:rs="urn:schemas-microsoft-com:rowset" xmlns:z="#RowsetSchema" xmlns:b="urn:schemas-microsoft-com:office:publisher" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" xmlns:c="urn:schemas-microsoft-com:office:component:spreadsheet" xmlns:odc="urn:schemas-microsoft-com:office:odc" xmlns:oa="urn:schemas-microsoft-com:office:activation" xmlns:html="http://www.w3.org/TR/REC-html40" xmlns:q="http://schemas.xmlsoap.org/soap/envelope/" xmlns:rtc="http://microsoft.com/officenet/conferencing" xmlns:D="DAV:" xmlns:Repl="http://schemas.microsoft.com/repl/" xmlns:mt="http://schemas.microsoft.com/sharepoint/soap/meetings/" xmlns:x2="http://schemas.microsoft.com/office/excel/2003/xml" xmlns:ppda="http://www.passport.com/NameSpace.xsd" xmlns:ois="http://schemas.microsoft.com/sharepoint/soap/ois/" xmlns:dir="http://schemas.microsoft.com/sharepoint/soap/directory/" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:dsp="http://schemas.microsoft.com/sharepoint/dsp" xmlns:udc="http://schemas.microsoft.com/data/udc" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:sub="http://schemas.microsoft.com/sharepoint/soap/2002/1/alerts/" xmlns:ec="http://www.w3.org/2001/04/xmlenc#" xmlns:sp="http://schemas.microsoft.com/sharepoint/" xmlns:sps="http://schemas.microsoft.com/sharepoint/soap/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:udcs="http://schemas.microsoft.com/data/udc/soap" xmlns:udcxf="http://schemas.microsoft.com/data/udc/xmlfile" xmlns:udcp2p="http://schemas.microsoft.com/data/udc/parttopart" xmlns:wf="http://schemas.microsoft.com/sharepoint/soap/workflow/" xmlns:dsss="http://schemas.microsoft.com/office/2006/digsig-setup" xmlns:dssi="http://schemas.microsoft.com/office/2006/digsig" xmlns:mdssi="http://schemas.openxmlformats.org/package/2006/digital-signature" xmlns:mver="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns:mrels="http://schemas.openxmlformats.org/package/2006/relationships" xmlns:spwp="http://microsoft.com/sharepoint/webpartpages" xmlns:ex12t="http://schemas.microsoft.com/exchange/services/2006/types" xmlns:ex12m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:pptsl="http://schemas.microsoft.com/sharepoint/soap/SlideLibrary/" xmlns:spsl="http://microsoft.com/webservices/SharePointPortalServer/PublishedLinksService" xmlns:Z="urn:schemas-microsoft-com:" xmlns:st="" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Steven,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>We successfully developed a methodology for simulating ground-coupled Multistack heat pumps in eQUEST. I have included below portions of our SEED Report (Oregon’s stated required program for publicly funded buildings). A lot of the text is specific to the project we were working on, but the general idea is there.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>The project ended up pursuing a standard chilled/heating water arrangement for the final design, so the Multistack heat pump was not installed.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I hope this information helps.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Regards,<br>Dana<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal>Heating and cooling will be provided by hot and chilled water, respectively, from a ground-coupled heat pump Multistack unit and will be connected to a condenser water vertical bore field. A Multistack unit is essentially a unit that contains a number of heat pump modules linked together in parallel. Depending on the load, each module can provide either heating water <i>or</i> chilled water. The condenser water loop is then connected to a vertical bore field onsite, where 200 ft deep bores located 20 feet on center is anticipated. The Multistack on this project utilizes seven modules. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>As eQUEST cannot directly model a Multistack unit, an alternate approach had to be taken in order to approximate the operation of the equipment. In summary, the Multistack was modeled in eQUEST by simulating each module of the Multistack as an individual chiller for heating and cooling. A general diagram on how the system is modeled in eQUEST can be seen in Figure 8 on the following page while more detailed explanations can be seen on the following pages.<o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><img width=644 height=774 id="_x0000_i1030" src="cid:image002.jpg@01CBC778.09F00940" alt="Mutlistack Diagram"></span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Figure: How the Multistack was simulated in eQUEST<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=Subheader>Chilled water<o:p></o:p></p><p class=MsoNormal>The chillers have a total flow of approximately 640 gpm and provide 45-degree chilled water with a 57-degree return water temperature. Connected to the chilled water loop are two pumps, in parallel that provide the 640 gpm flow.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Each chiller module is modeled as an electric hermetic centrifugal chiller with a capacity of 70 tons. Each stage is scheduled remain off until the stage before has been loaded to 100% and has an EER of 23 (EIR of 0.1483).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Default capacity curves were used for the preliminary analysis, however, customizes curves will be used once the information becomes available. A screenshot of the eQUEST layout in the Water-Side HVAC tab can be seen below in Figure 9.<o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><img width=645 height=447 id="Picture_x0020_2" src="cid:image004.jpg@01CBC778.09F00940"></span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=Subheader>Heating water<o:p></o:p></p><p class=MsoNormal>Since there is no heat pump boiler, an alternative method had to be developed to simulate the production of hot water. The heat pump chiller (LOOP-TO-LOOP-HP) in eQUEST is a heat pump that provides heating and chilled water simultaneously, with the larger load rejecting heat to the smaller load. This system could not be used for both the heating and cooling of the Multistack unit because it internal heat recovery when the dominant load rejects or adds heat to the small load. The Multistack has multiple smaller modules that operate in either cooling or heating only, and therefore do not provide integral heat recovery. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Since the LOOP-TO-LOOP-HP needs to be connected to a chilled water loop to work properly in eQUEST, the chillers had to be connected to a "dummy" chilled water loop. In order to avoid a "loop has zero flow" error, the loop had a minimal process chilled water flow that reset down to zero after the first hour of the year. The chillers were then connected to the hot water loop that serves the building. Since the hot water demand will always be higher than the dummy process chilled water flow the chillers will be driven by the hot water loop. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The chillers have a flow of 715 gpm and provide 110-degree hot water with a 90-degree return water temperature. Connected to the hot water loop are two pumps, in parallel, that provide the 715 gpm flow.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In eQUEST, it is required that secondary hot water pumps and chilled water pumps be connected to each heat pump chiller. Since the design is a variable primary flow and the chilled water is a dummy load, the secondary hot water pump power and the dummy chilled water pump power was zeroed out. <o:p></o:p></p><p class=MsoNormal>eQUEST also does not allow the heat pump chiller to be connected to any condenser water loop except the type "LAKE/WELL". In order to keep the ground coupled performance level, both the chilled water and heating water chillers connected to lake/well loops. Details of the condenser water loop can be seen in the next section. A screenshot of the eQUEST layout in the Water-Side HVAC tab can be seen below in Figure 9.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Also included in the design is a hot water condensing boiler to provide additional heating capacity during extreme peaking cooling. Since eQUEST uses TMY2 weather data that generally uses hourly averages, extreme cold days are never modeled, and therefore the boiler never turns on.<o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><img width=645 height=507 id="_x0000_i1028" src="cid:image006.jpg@01CBC778.09F00940"></span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=Subheader>Condenser water<o:p></o:p></p><p class=MsoNormal>Due to modeling limitations of the heat pump chiller, each condenser water loop was modeled as a LAKE/WELL loop. Each heating and cooling module was given its own loop to track and verify performance in the hourly reports. Each loop was scheduled to supply 55-degree condenser water back to the chillers, as scheduled in drawings. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The design consists of two condenser water loops connected in parallel. In the model, the two pumps were divided up amongst the chillers, with each pump set to single speed. Since each pump would only turn on when the chiller it was attached to was operating, it would loosely represent a variable speed drive pump with multiple stages. <o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Dana Troy</span></b><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><br></span><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Senior Energy Analyst</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><br></span><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>LEED AP<sup>®</sup></span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'> <br><br></span><a href="http://www.glumac.com/"><span style='font-size:12.0pt;font-family:"Times New Roman","serif";text-decoration:none'><img border=0 width=339 height=37 id="Picture_x0020_1" src="cid:image010.jpg@01CBC777.FF581770" alt="http://www.glumac.com/glumacsig.gif"></span></a><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><o:p></o:p></span></p><div><div><div><div><div class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><hr size=2 width=330 style='width:247.5pt' noshade style='color:#9ACB33' align=left></span></div></div></div></div></div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#1F497D'>320 SW Washington, Suite 200</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><br></span><span style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Portland, OR 97204-2640</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><br></span><span style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#1F497D'>T. 503.227.5280 F. 503.274.7674<br><br></span><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#333333'>Thinking. Inside the building.</span></b><span style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#333333'><a href="http://www.glumac.com/">www.glumac.com</a></span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'> <br><img border=0 width=309 height=23 id="Picture_x0020_3" src="cid:image011.gif@01CBC777.FF581770" alt="http://www.glumac.com/consider.gif"></span><span style='color:#1F497D'><o:p></o:p></span></p></div><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></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;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Steven Savich [mailto:ssavich@systemswestengineers.com] <br><b>Sent:</b> Tuesday, February 08, 2011 9:57 AM<br><b>To:</b> Dana Troy<br><b>Cc:</b> equest-users@lists.onebuilding.org<br><b>Subject:</b> Re: [Equest-users] Modeling Multstack Units in eQUEST<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><pre>Dana,<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>What solution did you end up using to model the Multistack heat pump chiller coupled to a vertical bore field in eQuest?<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Any pointers would be greatly appreciated.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Thanks,<o:p></o:p></pre><pre>Steven<o:p></o:p></pre><pre><o:p> </o:p></pre><p class=MsoNormal><span style='font-family:"Bookman Old Style","serif"'>Steven Savich, LEED AP</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Bookman Old Style","serif"'>Systems West Engineers</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Bookman Old Style","serif"'>411 High Street</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Bookman Old Style","serif"'>Eugene, OR 97401-2427</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Bookman Old Style","serif"'>(541) 342-7210</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Bookman Old Style","serif"'>(541) 342-7220 (fax)</span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><pre><o:p> </o:p></pre><pre>Has anyone had any luck modeling a Multistack<o:p></o:p></pre><pre>(<a href="http://www.multistack.com/">http://www.multistack.com/</a>) unit in eQUEST?<o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <o:p></o:p></pre><pre><o:p> </o:p></pre><pre>We have a project that uses a Multistack unit to provide hot and chilled<o:p></o:p></pre><pre>water to a project and is coupled to a vertical bore field. eQUEST does<o:p></o:p></pre><pre>not have the capability to model system directly, so I have been trying<o:p></o:p></pre><pre>to look into other methods, all which are falling short. So far I have<o:p></o:p></pre><pre>tried:<o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <o:p></o:p></pre><pre><o:p> </o:p></pre><pre>* Using the "Loop-to-Loop Heat Pump" chiller; however, this<o:p></o:p></pre><pre>system does not work like the Multistack, as the Multistack does not<o:p></o:p></pre><pre>have internal heat exchange, has multiple compressor stages which are<o:p></o:p></pre><pre>all piped in parallel with the condenser water, and can only be<o:p></o:p></pre><pre>connected to a Lake/Well loop.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>* Using a separate chilled water loop and hot water loop, each<o:p></o:p></pre><pre>of which are connected to a WLHP loop with a vertical bore HX. This<o:p></o:p></pre><pre>would be perfect, as I can put as many chillers and boilers on the loops<o:p></o:p></pre><pre>as there are stages in the Multistack; however, eQUEST does not have a<o:p></o:p></pre><pre>heat-pump boiler, so the boiler cannot be connected to the vertical bore<o:p></o:p></pre><pre>field.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>* Using a dummy space/zone/system connected to a dummy heat<o:p></o:p></pre><pre>recovery chiller. The chiller would then reject heat to the hot water<o:p></o:p></pre><pre>loop that supplies the rest of the building. This would work, however<o:p></o:p></pre><pre>the chiller demand is driven by the cooling load of the dummy system and<o:p></o:p></pre><pre>it is impossible to create a dummy cooling load that would exactly match<o:p></o:p></pre><pre>the heating load required by the hot water loop.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>* And finally, using a domestic hot water loop because the<o:p></o:p></pre><pre>boiler type can be set to "heat pump", however, the heat cannot be<o:p></o:p></pre><pre>rejected to a condenser water loop.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <o:p></o:p></pre><pre><o:p> </o:p></pre><pre>So I guess the question I am asking is has anyone either successfully<o:p></o:p></pre><pre>modeled the Multistack unit OR modeled a heat pump boiler?<o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Thanks in advance.<o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <o:p></o:p></pre><pre><o:p> </o:p></pre><pre>-Dana<o:p></o:p></pre><pre><o:p> </o:p></pre><pre><o:p> </o:p></pre><pre>Dana Troy<o:p></o:p></pre><pre>Energy Analyst<o:p></o:p></pre><pre>LEED(r) Accredited Professional<o:p></o:p></pre><pre><o:p> </o:p></pre><pre> <<a href="http://www.glumac.com/">http://www.glumac.com/</a>> <o:p></o:p></pre><pre><o:p> </o:p></pre><pre>________________________________<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>320 SW Washington, Suite 200<o:p></o:p></pre><pre>Portland, OR 97204-2640<o:p></o:p></pre><pre>T. 503.227.5280 F. 503.274.7674<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>Thinking. Inside the building.<o:p></o:p></pre><pre>www.glumac.com <<a href="http://www.glumac.com/">http://www.glumac.com/</a>> <span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></pre></div></body></html>