<p dir="ltr">Thanks Daniel. It seems you're right and maybe the curve is not intended to be used outside the range you mentioned.</p>
<p dir="ltr">Thank you everybody for the quick responses.</p>
<div class="gmail_quote">El 18/11/2015 19:45, "Daniel Knapp" <<a href="mailto:danielk@arborus.ca">danielk@arborus.ca</a>> escribió:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I’m not sure I understand why the 39+ capacity curve falls after after 54ºF, but I don’t think that the 39+ and 39- curves have been switched. The 39+ curve goes negative at about 11ºF so it won’t work as a replacement for the 39- curve. Also the 39- curve flattens out as it drops to -13ºF and then starts to rise again. I suspect the curves are intended to be used over an operating range of about -10ºF to 50ºF. Below -10ºF the heat pump chiller shuts off and goes to supplemental resistance heating. Above 54ºF the heat pump chiller is unlikely to have a call for heating? It does seem a bit strange.<br>
<br>
Cheers,<br>
Dan<br>
<br>
—<br>
Daniel Knapp, PhD, PPhys, LEED® AP O+M<br>
<a href="mailto:danielk@arborus.ca">danielk@arborus.ca</a><br>
<br>
Arborus Consulting<br>
Energy Strategies for the Built Environment<br>
<a href="http://www.arborus.ca" rel="noreferrer" target="_blank">www.arborus.ca</a><br>
76 Chamberlain Avenue<br>
Ottawa, ON, K1S 1V9<br>
Phone: <a href="tel:%28613%29%20234-7178%20ext.%20113" value="+16132347178">(613) 234-7178 ext. 113</a><br>
Fax: <a href="tel:%28613%29%20234-0740" value="+16132340740">(613) 234-0740</a><br>
<br>
<br>
<br>
<br>
> On Nov 18, 2015, at 11:49 AM, Fernando Varela <<a href="mailto:fvarela@ind.uned.es">fvarela@ind.uned.es</a>> wrote:<br>
><br>
> Dear Bill and Jeff:<br>
><br>
> The problem arises when you plot for a fix hot water outlet (let's say 113ºF) the whole curve for exterior temperatures (from 9 to 59ºF), using the expression of 39- curve for values till 39ºF and 39+ for the rest of them.<br>
><br>
> It shows like this:<br>
><br>
> <image.png><br>
><br>
> Shouldn't COP increase with higher exterior temperatures for a fixed hot water outlet temperature? It seems even to decay after 54ºF...<br>
><br>
> With capacity curves is the same, but in that case it makes more sense.<br>
><br>
> Thanks.<br>
><br>
><br>
><br>
> Fernando Varela Díez<br>
> Dpto. Ingeniería Energética - ETSI Industriales<br>
> Email: <a href="mailto:fvarela@ind.uned.es">fvarela@ind.uned.es</a><br>
> Tlf: 91 398 6468<br>
><br>
> Universidad Nacional de Educación a Distancia (UNED)<br>
> C/ Juan del Rosal, 12. Despacho 2.20<br>
> Ciudad Universitaria, 28040, Madrid<br>
><br>
><br>
><br>
> 2015-11-17 16:03 GMT+01:00 Bishop, Bill <<a href="mailto:bbishop@pathfinder-ea.com">bbishop@pathfinder-ea.com</a>>:<br>
> Fernando,<br>
><br>
> The curves look okay to me. I plotted them out for a range of hot water temperatures from 90F to 130F.<br>
><br>
> - I plotted the “…39+” curve for the range of entering dry bulb from 40F to 60F.<br>
><br>
> - I plotted the ”…39-“ curve for the range of Edb from 20F to 38F.<br>
><br>
> - Both curves show decreasing capacity as the heat pump chiller makes hotter water, which makes sense.<br>
><br>
> - Both curves show decreasing capacity with lower outside air condenser temperatures, which makes sense.<br>
><br>
> - The “…39-“ curve shows rapidly decreasing capacity with decreasing condenser temperature below 39F, which makes sense since larger portions of the chiller heat pump heat is needed to defrost the condenser coils.<br>
><br>
> - I’m guessing that the curves are normalized to 110F HWT and 44F Edb.<br>
><br>
> I can share an Excel file I used to generate the curves and chart if anybody wants it.<br>
><br>
> ~Bill<br>
><br>
><br>
><br>
> <image001.png><br>
><br>
><br>
><br>
><br>
><br>
> William Bishop, PE, BEMP, BEAP, CEM, LEED AP | Pathfinder Engineers & Architects LLP<br>
><br>
> Senior Energy Engineer<br>
><br>
> <image010.jpg> <image011.jpg><br>
><br>
><br>
><br>
> 134 South Fitzhugh Street Rochester, NY 14608<br>
><br>
> T: (585) 698-1956 F: (585) 325-6005<br>
><br>
> <a href="mailto:bbishop@pathfinder-ea.com">bbishop@pathfinder-ea.com</a> <a href="http://www.pathfinder-ea.com" rel="noreferrer" target="_blank">www.pathfinder-ea.com</a><br>
><br>
> <image012.png>Carbon Fee and Dividend - simple, effective, and market-based.<br>
><br>
><br>
><br>
><br>
><br>
> From: Equest-users [mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a>] On Behalf Of Fernando Varela<br>
> Sent: Tuesday, November 17, 2015 5:04 AM<br>
> To: <a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br>
> Subject: [Equest-users] eQuest heat pump performance curves<br>
><br>
><br>
><br>
> Dear users:<br>
><br>
><br>
><br>
> I've noticed that eQuest heat pump performance curves:<br>
><br>
><br>
><br>
> ChlrHPAirHeatCap-fHW&39+<br>
><br>
> ChlrHPAirHeatCap-fHW&39-<br>
><br>
><br>
><br>
> which refer, respectively, to the temperature capacity factor of the heat pump in normal and defrost mode, seem to be exchanged. This is, ChlrHPAirHeatCap-fHW&39+ curve seems to be the defrost mode curve, and ChlrHPAirHeatCap-fHW&39- the curve regarding to normal mode.<br>
><br>
><br>
><br>
> I've plotted (with fixed condensing temperature) both capacities varying exterior temperature, and observing the results taking the curves in the opposite way as it shoud be (below 39ºF,ChlrHPAirHeatCap-fHW&39+, and ChlrHPAirHeatCap-fHW&39- above 39ºF ), the resulting HP capacity curve seems more like it should be.<br>
><br>
><br>
><br>
> Am I doing something wrong?<br>
><br>
><br>
><br>
> Thank you in advance.<br>
><br>
> <image013.jpg><br>
><br>
> Fernando Varela Díez<br>
> Dpto. Ingeniería Energética - ETSI Industriales<br>
> Email: <a href="mailto:fvarela@ind.uned.es">fvarela@ind.uned.es</a><br>
> Tlf: 91 398 6468<br>
><br>
> Universidad Nacional de Educación a Distancia (UNED)<br>
> C/ Juan del Rosal, 12. Despacho 2.20<br>
> Ciudad Universitaria, 28040, Madrid<br>
><br>
><br>
><br>
><br>
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</blockquote></div>