I'm aware of TRACE's ability to model geothermal chiller-heaters using bi-directional cascade effects, but how can I get TRACE to do this without a ground loop?  All I have is the evaporater side of the chiller producing chilled water and then rejecting the heat to the condenser side where it supplements the fossil fuel boilers. 

Can I just set the heat rejection type from "ground loop" to "heating plant" and then specify my backup boiler?  If I do this, I loose the ability to select "bi-directional cascade." Is this okay?

Finally, if this chiller is one of several chillers in a chiller plant, should it be sequenced in a "side-car" or "base load" arrangement?

Thanks!