Net ZEB Case Studies - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 376

heat pump. To resolve this, the controls were tweaked. As a result, the space
doesnotreachthedaytimesetpointasquickly.Anothermethodforreducing
energy use would be to delay the setpoint increase until after some solar
gainshaveoccurred(around10A.M.)suchthatthespaceiswarmedforfree.
The suitability of this approach depends on the lifestyle of the occupants.
As can be expected, the rooms of the house are not being used exactly as
planned. The most extreme instance of this is that the garage was converted
into a workshop. To warm the space, the owners installed a 5 kW electric
resistance heater. For the few months that this went undetected by the
Concordia University research team, this heater was using one-third of the
electricity that was used to heat the entire house! This is despite the fact
that the garage represents a mere 10% of the floor area of the house and
was never heated to the temperatures of the rest of the house. If the space
must be heated, it would be favorable to either heat it with the central heat
pump, or more interestingly, with the BIPV/T roof. Since the BIPV/T outlet
air is often less than 15 °C, it would still be of use in the garage (due to
adaptive comfort, elevated activity levels, and the fact that warm clothes
may be warn) despite not being useful in the house.
The shallow ÉcoTerra roof slope resulted in poorer than expected BIPV/T
performance. A solution to overcome this (for future houses) would be to
build the roof on-site to remove the constraint from module transportation.
Alternatively, a heater could be used to act as a catalyst in melting snow.
More complex approaches could be to route exhaust ventilation air through
the BIPV/T air space or to have a small steeper solar collector that is used
to melt snow. While all of these solutions come at some cost (energy,
equipment),itmaybeworthwhileconsideringthatmeasuredwintertimePV
generation was only at a fraction of its potential.
Despite the high resolution of monitoring equipment for certain aspects of
the house performance - particularly the innovative technologies - it would
have been ideal to submeter many of the electricity consumers, including
lights, appliances, the HRV and air cleaner, and the other fans. A total
of two-thirds of the electricity use is measured only in aggregate form,
leaving some uncertainty as to exact final use. As a result, detailed studies,
such as understanding the electric lighting use and its relationship with
occupancy and daylight availability, cannot be performed. Another aspect
of monitoring that could be improved is to have a single data acquisition
system recording all data. In the current configuration, the heat pump is