Modeling GLHP systems

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Dear All:

I am trying to model a ground loop heat pump system in equest, but I keep
getting the following errors: " WLHP loop: Ground Loop has exceeded a
hi/low alarm limit and will shut down associated HVAC equipment for the
hour. Loop T: 17.91 Limit: 20.00. Verify that alarm limits are
reasonable, verify primary equipment sizing, especially ground-loop
heat-exchangers, and verify that the HP performance curves are suitable for
the intended operating range." as well as "Ground-loop HX: Ground Loop Heat
Exchanger 1 is undersized for the load and is producing an extreme
temperature of -4F."

Since the design is a closed loop system (vertical pipes) I have created a
GLHE of type 'Vertical Well-Sweden G-function', connected to a circulation
loop of the type 'water loop heat pump'. I have also inserted the GSHP
curves from DOE 22. I'm not sure if the problem is the parameters I have
defined in the model, or from the way I have set things up in EQUEST. I
would really appreciate it if someone with more experience than me can help
me out with my problem. I have attached my files in case someone has the
time to take a look at them.

Best Regards,

Behnam Jowkar, MASc, BEng, LEED GA

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FYI, eQUEST does not auto-size the ground loop. If you haven?t entered the number of boreholes, etc. then eQuest won?t create a ground loop of sufficient size.

Best,

Daniel Knapp, PhD, P Phys, LEED? AP O+M

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