Probably I?ll have to model a "packaged unit for simultaneous and
independent production of heating and cooling energy" (in other words, a
"polyvalent system"): it is a heat pump that works among the hot water
loop, the chilled water loop, and water coming from an aquifer (open loop).
You can see pages 5, 8, and 20-22 of this brochure:
http://www.flaktwoods.com/d2005274-af58-418a-9a2b-8d7a63bee1ee

Through a heat exchanger connected with the hot water loop, the system can
produce also domestic hot water.

Consider that the three loops (hot water, chilled water, source) can be
?on? at the same time. Consider summer conditions: the building needs
cooling and domestic hot water, but the DHW requirements aren?t very
important. The part of rejected heat that isn?t necessary for the DHW
production is transferred to aquifer water.

Have you ever modeled such a system? With which software? Did you have to
post process the output data (if it was a LEED application, did you follow
the ?exceptional calculation method??)

I think that there two problems:
1) modeling the fact that part of the heat that is rejected by the chilled
water loop through the heat pump is transferred to the hot water loop
2) modeling the fact that water can be taken from the aquifer; heat can be
transferred to the aquifer water if the cooling need is greater than the
heating need or, vice-versa, heat can be taken from the aquifer if the
heating need is greater than the cooling need.

Thank you for your attention.

Regards