Hello,
I've got a question about the NECB Reference Building heating system type
for Multi-Unit Residential Buildings. Specifically what should it be when
you have water-loop heat pumps connected to a fossil fuel boiler?
Table 8.4.4.7.-A of the 2015 NECB states that Reference Building HVAC
systems for Multi-Unit Residential areas are:
"Where the proposed building or space is heated as well as being cooled with
an air-cooled unitary, packaged terminal or room air conditioner (or heat
pumps), or fan coils, the reference building or space's HVAC system shall be
modeled as being identical to that of the proposed building or space;
otherwise, the reference building or space shall use through-the-wall
systems."
I'd consider water-loop heat pumps to be in the "through-the-wall systems"
category so the cooling would be air-cooled DX. It doesn't describe the
heating source for "through-the-wall systems" but 8.4.4.9.4 says that the
energy type of the reference building's heating system shall be identical to
the energy type of the proposed building's heating system. The code
considers heat pump to be an energy type so I think it should be an
air-source heat pump. I'm just not sure about the auxiliary heat - electric
resistance or hot water?
I tried running this in CAN-QUEST but got some errors. When I run a
4-storey office building with WLHP, the reference building is coming out as
air-source heat pump with electric resistance heat so I'm leaning toward
using that. I can see there being an argument for hot water auxiliary heat
though based on the proposed building having a fuel-fired boiler (to avoid
fuel switching).
Thanks,
Aaron
Aaron Smith, P.Eng
Principal, Mechanical Engineer
LEEDR AP BD+C, BEMP, BEAP, CGD
t: (902) 422-7393
f: (902) 423-4945
e:
www.mreng.ca
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