I am modeling a mixed use commercial retail, offices (3 floors) and residential tower (20+ floors) to meet and exceed 90.1-2007. Climate zone 5.  Retail and offices are heating and cooling  using water souce heat pump with condensing boiler. Heat rejection is through parkade exhaust fan system (in lieu of cooling tower). Residential tower is heating only hot water baseboard heating using condensing boiler. According to 90.1-2007, the residential units to be modeled with cooling as packaged AC unit. In Trace700,  I set up the systems accordingly, and the cooling plant for WSHP and PTAC. Heating plant with boiler.

1) how can I separate the commercial portion and the residential portion? my first run seems the program using the WSHP for heating the whole building.

2) how to model the energy saving of heat rejection to the parkade exhaust fan in lieu of cooling tower?

Thanks.