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<DIV>Pasha:</DIV>
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<DIV>Thank you for the response. The system I am modeling is 4-pipe with a heat recovery chiller and two air cooled heat pumps that will suppliment either chilled or hot water as needed. The equipment is European, Trane. From what I am reading, both in system descriptions in DOE2 and equipment literature, the heat pumps usede are really designed for a 2-pipe system, thus not easily modeled drectly. The design has 3-way valves directing water from each heat pump to either loop. I read through the water to water system, I think there is a chance energy use modeled that will not happen in reality.</DIV>
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<DIV>Based on the equpment sizes, and on preliminary model results, i do not see both heat pumps running AND the chiller at the same time. So, I am pretty sure i can do the following:</DIV>
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<DIV>Chilled water plant: Heat recovery chiller and one heat pump to provide chilled water. there is enough capacity here to provide peak cooling of the building plus a little to spare.</DIV>
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<DIV>Hot water heating : heat from the revcovery chiller, and two electric boilers sized and modeled to mimic the capacity and EIR (inverse of COP) of the heat pumps. The only time the building may require enough heat to run both heat pumps, there is little if any chance the cooling needs would have to be met by both the chiller and a heat pump.</DIV>
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<DIV><STRONG>I guess I am asking if anyone can pick apart this logic. </STRONG></DIV>
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<B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> Pasha Korber-Gonzalez <pasha.pkconsulting@gmail.com><BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> Paul Brooks <equestpaul@yahoo.com><BR><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B> Tue, June 8, 2010 3:01:14 PM<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [Equest-users] how to model an air cooled heat pumpfor hot water<BR></FONT><BR>
<DIV>Paul,</DIV>
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<DIV>I have run into this similar issue, just because the system is available in real life doesn't mean that it can be modeled in DOE2 (at least not at this point in time.)</DIV>
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<DIV>Suggest reading up on your "Water-to-Water HP" system & the "Loop-to-loop HP" option in the attached file from DOE2. I learned that I can select these units but they will only work when attached to a geothermal loop for heat rejection, but I think what you are wanting is the Water-to-water HP which will then allow you to connect to the HW Loop for HW supply. The unforntunate thing here is that DOE2 will not let you model your heat rejection to the air or even a cooling tower, it <U>has</U> to be connected to a circulation loop of type-lake/well for the heat rejection part...you will have to use engineering judgement and additional calcs to modify your results to represent the heat rejection of the air-cooled unit in real life.</DIV>
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<DIV>Start with the attached doc, and then feel free to connect back with me for more details on how I used eQuest to represent a similar approach that you are trying to take.</DIV>
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<DIV>cheers,</DIV>
<DIV>pasha<BR><BR></DIV>
<DIV class=gmail_quote>On Tue, Jun 8, 2010 at 11:44 AM, Paul Brooks <SPAN dir=ltr><<A href="mailto:equestpaul@yahoo.com" rel=nofollow target=_blank ymailto="mailto:equestpaul@yahoo.com">equestpaul@yahoo.com</A>></SPAN> wrote:<BR>
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<DIV>I have a system that is using an air cooled heat pump to provide chilled water for cooling, and or hot water for heating. I tried modeling an aircooled heat pump, but was unable to connect the heating side to the hot water loop. </DIV>
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<DIV>It seems the best thing to do is to model an electric boiler, and make the operating chatictaristics mimic a heat pump. any thoughts? </DIV>
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