Secondary chiller in plant loop in 5ZoneVAV Chilledwaterstorage idf
In the EnergyPlus Example files for Chilled Water Storage-Mixed vs Stratified(5ZoneVAV-ChilledWaterStorage-Mixed.idf & 5ZoneVAV-ChilledWaterStorage-Stratified.idf), the Secondary chiller is present in the Mixed storage idf while only Primary in stratified idf file. What is the logic or rule to configure the plant loops and when we should consider using two chillers vs only one with TES implemented?
Unless the author of these files comes by, I'll go on a limb and say that there's no logic or rule, they just decided to put another one... It might not even have been the same person that did the two examples.