Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 214

Visual Comfort
The objectives of electric lighting and daylighting are to ensure adequate
light levels to achieve the task at hand, ensure that conditions are not too
bright and avoid glare, and minimize total energy use (electric lighting
energy and the resulting HVAC energy required to remove unwanted heat
gains). Visual comfort metrics based on workplane illuminance, while being
the conventional method for controlling electric lighting, has not yielded
consistent predictions of daylight glare (Wienold and Christoffersen, 2006).
Daylightglareprobability(DGP)(WienoldandChristoffersen,2006),which
is based on vertical eye illuminance, glare source luminance, and occupant
orientation and position, has demonstrated - through experiments - good
predictions of visual discomfort. Daylighting and DGP can be quantified
in several BPS tools, including OpenStudio/Radiance, DAYSIM, Evalglare,
and DIVA for Rhino. Effort should be made to minimize the occurrence
of glare through careful sizing and positioning of glazing, exterior fixed
shading, appropriate selection of surface reflectances, providing furniture
and floor layouts with flexible occupant positioning, and installing effective
window shades/blinds. Aside from causing visual discomfort and reducing
productivity in workplaces, frequent glare can motivate occupants to
semipermanently close window blinds and prevent useful daylight from
entering the space (O'Brien, Kapsis, and Athienitis, 2013). Hourly or
sub-hourly analyses should be performed because even momentary diurnal
glare can prompt occupants to leave blinds closed (Bordass, Leaman, and
Willis, 1994; Reinhart, 2004). All of these strategies can be tested using the
aforementioned tools.
Acoustic Comfort
Several common strategies in Net ZEBs (openness of interiors, hard
surfaces, exposed thermal mass, and operable windows) are generally
contradictory to good acoustic performance, as explained in Chapter 3 . For
that reason, coupling an acoustic model into a building performance model
with detailed occupant model could yield some insightful results.
During the design and modeling of Net ZEBs, detailed knowledge of interior
surfaces (including furnishings) including scattering coefficient and
impedance is very useful. However, as with daylighting simulation, detailed
acoustical information is typically not known until the later stages of design.
Thus, reasonable estimates of these properties must be made earlier in