Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 215

design, when the architect or interior designer has the best opportunity to
select good acoustic strategies. Using the daylighting analogy again, it is
possible to use acoustic simulation approaches to “auralize” a room such
that the simulationist can produce the predicted acoustic environment of
a building before it is built. Several tools for acoustic assessment in BPS
are available, including CATT-Acoustic and the ESP-r acoustic module.
Mahdavi (2012) stated several future needs of building acoustics simulation
including more detailed algorithms and an extensive and accurate database
of material acoustical properties.
4.3.3.7 Occupant Behavior
The role of occupant behavior in a Net ZEB cannot be overlooked because
suchbuildingscanbeparticularly sensitivetooccupants(Hoes etal. ,2009).
Occupant behavior has been shown to affect energy use by a factor of two
or more (Gram-Hanssen, 2010; Haldi and Robinson, 2011). Many studies
(O'Brien, Kapsis, and Athienitis, 2013; Rubin, Collins, and Tibbott, 1978;
Saldanha and Beausoleil-Morrison, 2012) have demonstrated that
predicting the energy use associated with occupant behavior is quite
difficult; especially if occupants are not motivated by cost savings (e.g., in
their workplace) (Rea, 2000). Buildings with passive features (e.g., natural
ventilation) often give more control to occupants to maintain comfort,
which can also lead to significant uncertainty (Hoes et al. , 2009). Also, as
building envelopes become better-insulated, HVAC systems become more
efficient, and the number of electricity-consuming devices (e.g., computers
and appliances) increases, the so-called plug loads contribute an increasing
share of total energy use. The challenge associated with designing for plug
loads is that they are often based on small appliances and other equipment
that occupants install themselves after the design is realized. While plug
loads are often considered beyond the control of building designers and in
the past, merely quantified to estimate peak cooling loads for HVAC sizing,
the Net ZEB definition normally positions them within the energy balance.
Therefore, Net ZEB designers must estimate them with better accuracy and
even try to influence them through good design. This is especially true in
small buildings and houses, where the energy use is largely at the mercy of
the habits of the occupants and not formally managed. In larger buildings,
the diversity of occupants normally reduces energy use uncertainty.
The value of comfort (thermal, visual, and acoustic) and productivity (in
the workplace) is paramount. If a building does not provide comfortable