[Equest-users] eQuest heat pump performance curves

[Bishop, Bill]

Fernando,
The curves look okay to me. I plotted them out for a range of hot water temperatures from 90F to 130F.

-        I plotted the “…39+” curve for the range of entering dry bulb from 40F to 60F.

-        I plotted the ”…39-“ curve for the range of Edb from 20F to 38F.

-        Both curves show decreasing capacity as the heat pump chiller makes hotter water, which makes sense.

-        Both curves show decreasing capacity with lower outside air condenser temperatures, which makes sense.

-        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.

-        I’m guessing that the curves are normalized to 110F HWT and 44F Edb.
I can share an Excel file I used to generate the curves and chart if anybody wants it.
~Bill

[cid:image001.png at 01D1211F.2E537820]


William Bishop, PE, BEMP, BEAP, CEM, LEED AP | Pathfinder Engineers & Architects LLP
Senior Energy Engineer

[cid:image010.jpg at 01D1211F.2E537820]  [cid:image011.jpg at 01D1211F.2E537820]



134 South Fitzhugh Street                 Rochester, NY 14608

T: (585) 698-1956                        F: (585) 325-6005

bbishop at pathfinder-ea.com<mailto:wbishop at pathfinder-ea.com>             www.pathfinder-ea.com<http://www.pathfinder-ea.com/>

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From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Fernando Varela
Sent: Tuesday, November 17, 2015 5:04 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] eQuest heat pump performance curves

Dear users:

I've noticed that eQuest heat pump performance curves:

ChlrHPAirHeatCap-fHW&39+
ChlrHPAirHeatCap-fHW&39-

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.

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.

Am I doing something wrong?

Thank you in advance.
[Image removed by sender.]


Fernando Varela Díez
Dpto. Ingeniería Energética - ETSI Industriales
Email: fvarela at ind.uned.es<mailto:fvarela at ind.uned.es>
Tlf: 91 398 6468

Universidad Nacional de Educación a Distancia (UNED)
C/ Juan del Rosal, 12. Despacho 2.20
Ciudad Universitaria, 28040, Madrid


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