I couldn't find any postings on this subject, but maybe I was just using
the wrong search words so here goes. I'm trying to model a geothermal
system that runs open loop from a large aquifer with a 10 deg change in
the water replaced into the aquifer. There will be 2-4 large heat pumps
operating on hot and cold water loops with one heat pump operating
between the two loops. See attached diagram.
The air side of the system will be 4 pipe fan coils since the
maintenance team is familiar with this type of system. There will be a
condensing boiler for backup heating.
* how to simulate an open loop ground well?
* do i need to create hot, cold and GSHP loops under water-side
HVAC...if so how do I tie them together?
Any tips on how to model this system will be very helpful, Thanks much!
Jacob Goodman , LEED AP
Hi Jacob,
Open loop geothermal systems are not explicitly model-able within
eQuest, but you're not out of luck. Use another program to determine
monthly or weekly annual ground loop temperature behavior (whoever did
your field sizing/design should be able to produce this), define a
Lake/Well GLHX in detailed mode, and create/assign a schedule of those
temperatures to the GLHX.
For more information, seek my contributions to the following thread in
the archives (I wrote something of a mini-guide to your situation):
Re: [Equest-users] [Bldg-sim] loop to loop heatpump in equest
Sorry to be brief but this should give you a good direction to run in ;)
NICK CATON, E.I.T.
Jacob,
I'm sure you've figured this out by now but eQuest has substantial
limitations with regards to the system you're trying to model.
I would start by reading all the pertinent threads dealing with loop to loop
heat pumps and heat recovery chillers to get an idea of what can and can't
be done (lots to learn there).
If your "open loop" is a production - reinjection type setup, the initial
temperature will be close (within 5o) to the mean annual outdoor air
temperature. I'll spare you all the disclaimer's with regards to that
statement!
Anthony Hardman