Ground Source Water-to-Water HP in eQuest

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This topic appears to be a gray area within eQUEST. Has anyone been able to successfully model a Ground Source Water-to-Water HP connected to a closed loop Geothermal Well Field?

The WWHP is to serve a radiant floor. In addition to the WWHP, the design also has multiple Water-to-Air Heat Pumps connected to the same well field. Issues rise when trying to figure out how to model the effect of the WWHP on the Well Loop.

In the past I have used the Loop-to-Loop Chiller to model a WWHP, but the chiller requires a connection to a Lake-Well type loop.

Thanks in advance.

Robert Garcia

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I believe the methodology that has been implemented with success is to
use the WTW HPs with the lake well, but to use a schedule for well water
temperatures either taken from a separate run with WTA and closed loop,
or to take the temperatures from another yearly sim in either GLHE-PRO
or GS2000.

Alan Jackson, LEED AP

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That's pretty much what I've done for a few projects.

1. Calc your loads incident on the loop, either using eQuest or
another program

2. Use those loads to determine the annual thermal behavior of the
ground loop using a program like the free GS2000 or a similar
ground-loop design tool.

3. Use the thermal behavior output of your ground-loop software of
choice to create a custom temperature schedule. If you want a more
detailed explanation of the step-by-step process within eQuest, search
for my name in the eQuest/Bldgsim archives.

NICK CATON, E.I.T.

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If you don't want to use outside programs to estimate the ground heat
exchanger response, you can input the condenser loads directly into the
ground heat exchanger water loop as a process load.

For GSHP's, just make sure you're using heat of extraction spec data for
your condenser loads, not total heating capacity.

Integrating the loads from multiple systems (DHW, Bldg, et. al.) into a
single GHX also yields a more cost effective (fewer bores) GHX from an
installation perspective.

Anthony Hardman

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ClimateMaster had a bundled version of eQuest with an add-on for
simulating GSHP. It's free.
http://www.climatemaster.com/index/equest

David Elfstrom, P.Eng, LEED? AP

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