Hi All,

I have modeled a multifamily building for LEED which uses a variable
refrigerant flow system. In the building each stack of apartment's heating
and cooling is provided by one unit, but the stack next door is provided by
a different unit. The efficiency is determined by the outdoor unit and
varies slightly by size, which is not the same for all apartment units. I
have modeled several apartments as one thermal block and I had calculated an
overall system efficiency by doing a weighted average based on system size.
My reviewer has commented that per G3.1.10a I need to use the individual
system size and efficiency for each system. I am wondering if they will
accept a weighted average by thermal block instead of an overall system
average. It seems quite clear under G3.1.9 that modeling multiple
apartments on the same wall is perfectly acceptable. Do you need to have
multiple systems serve each zone? I did not think this is possible.

Any thoughts/experience with this situation would be greatly appreciated.

Thanks,

Michael Shields