We are working on a CI-Certification of a tenant space (5 floors) in a highrise building with around 40 floors. The tenant does not have influence on the central HVAC system.
The main building is connected to a district heating system. Cold production is provided by central chillers and ice storage.

We modelled the tenant space with purchased heat. That means that we used typical local energy rates for heating, cooling and electricity without considering how the hot or cold water is produced.
However we now received a review comment which states that we should use the "Treatment of District or Campus Thermal Energy in LEED v2 and LEED 2009". Table 1 (EAc1 points restrictions) of this document points on Appendix A which says: "For Projects under the LEED-CI rating system DES have no effect on any EA section prerequisites or credits."

For me this means that the district heating as well as the cold production of the basebuilding does not have to be considered in EAc1.3.

Do we have to model the Proposed and Baseline Case with the standard boiler and chiller according ASHRAE?
Should we model the tenant space with purchased heat according ASHRAE 90.1.2007, App. G3.1.1.1 Purchased Heat using typical energy rates? This would actually be same the approach as we already used.