I've chatted with Rashmi and feel like others may want to know how this
can be done in the future... Also copying [Equest-users] on this
discussion as advised by a list administrator.

See attached screengrab for a simple visual of how I accomplished
this...

Setting up the 4-pipe system sourced from a closed ground loop:

1. Create a 'chiller' of the type 'water-to-water heat pump'
2. Create an independent circulation loop of the type 'lake/well'
3. Create a ground loop heat exchanger of the type 'lake/well'
4. Select as the chiller CW loop and GLHX circulation loop the
independent loop you created - they should connect without errors
5. Assign a custom temperature schedule for the lake/well ground
loop in the screen that pops up when you double click the GLHX (read on)
6. Make sure the default head/pump properties for the circulation
loop and GLHX make sense for your system - adjust as necessary. (i.e.
if it's a closed ground loop, there shouldn't be static head)

The tricky thing is that both Rashmi and I were dealing with closed-loop
ground heat exchanger (not lake/well). The solution I came to model
this was to temporarily save the project in a separate directory to keep
my work, then go back to the wizards and heat/cool the same building
reasonably using the DX/DX heating/cooling ground source heatpump
option, with all appropriate ground and field properties well defined.

Once this is done, you can have eQuest additionally generate an hourly
report over of the resulting ground loop temperatures throughout the
year (actual procedure eludes my memory, but it's in the archives).
Once this is done, I used that raw data to come up with the resulting
weekly average temperatures in the ground loop using excel. I then used
these figures to create a custom temperature schedule for the actual
project, which was assigned to the GLHX as mentioned above. This way
you're reasonably accurately representing what temperatures the
water-to-water equipment is seeing coming out of the ground throughout
the year based on your actual geographic, ground loop, and soil
condition variables as defined.

The final logical step, and one I'm currently working on learning for
myself, is defining a custom performance curve for the water-to-water
equipment that's representative of the real thing. I have been advised
the default chiller curves as well as the water-to-air heatpump curves
from the Climatemaster eQuest add-on are not appropriate for modeling
water-to-water heatpumps.

Best of luck!

PS: Apologies for the screenshot's quality - I had issues making it
small enough for the mailing list to accept.

NICK CATON, E.I.T.