I am working on a project that has 2 buildings each one will be submitted to LEED as a separate project. The first building is an office building that is served by water cooled self-contained units. The second building is a residential building that is served by water source heat pump. The first two floors of the residential building are retail spaces served by WSHPs. The WSHP of the retail spaces are connected to the office building condensing plant via a heat exchanger and there will be an energy meter to measure the energy cost. ASHRAE 90.1 does not have guideness about purchased condensing water. I am thinking of modeling the same condensing plant equipment of the office building for the retail spaces to account for the energy cost, is this a reasonable approach? The other option I am thinking of is modeling the retail spaces with the same system as the baseline.

Thank you,