[Equest-users] LEED Review Comment - District Energy with Different HVAC Systems

[Michael Mantai]

We submitted a model that included two different baseline HVAC system types.
It is a manufacturing building with an office space included.  The
production spaces are most of the building square footage, and based on the
size have a System Type 5.  The building uses district steam for heating in
the air handling units serving the production spaces, so we applied the
District Energy rules and modeled both the baseline and proposed cases with
steam heating.  However, I claimed an exception on the office area due to
different loads and schedules and modeled that space with a Baseline System
3.  The actual building is using a VRV heat pump system in the office area,
so I did not apply the rules of the District Energy guidance to that system;
instead I modeled the baseline as having a gas furnace per 90.1.  The LEED
reviewer did not comment on the use of the different baseline systems, but
they did comment that the System 3 in the baseline needed to be modeled
using steam per the District Energy guidance.  I've read the guidance and it
does not appear to provide any rules for buildings that have HVAC systems
that use a combination of packaged heating and district heating.  It seems
ludicrous to model 1-ton packaged rooftop units with steam heat in the
baseline when the proposed case doesn't use steam.  Anyone else dealt with
this scenario?