Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 158

with complex integrated systems. However, their simplicity allows them to
offer more design guidance than advanced tools. Designers alternate theuse
of different tools in an iterative way during each design phase to obtain the
desiredenergyperformance.Thissectiontakesacloserlookathowdifferent
tools can be integrated to the concept design, design development, and
technicaldesignstagesofNetZEBs.Thesuggestedtoolsarecommonlyused
by building designers. They only represent a small fraction of all building
energy simulation software available on the market. A comprehensive
database of BPS programs can be found in the tools directory developed by
the US Department of Energy (DOE) (2013a).
4.2.4 Concept Design
When designing Net ZEBs, the intent is to reduce building energy
consumption first. In the concept design stage, the aim is to approach this
goal by prioritizing the following building aspects:
1. Daylight
2. Solar protection
3. Building thermal inertia (thermal mass)
4. Natural ventilation
5. Building envelope insulation
6. Building-integrated solar energy technologies.
These aspects all need to be considered because they help define essential
parts of the architectural concept - including building form, orientation of
surfaces, and fenestration - and are difficult to modify at a later stage of the
design.Iftheseaspectsareaddressedcarefullyduringtheearlydesignphase
and the operation of the building is considered, achieving net-zero energy
can be a realistic goal. These aspects influence each other and are essential
to optimize a building for solar energy collection. For example, compact
buildingsthathaveasmallenvelopeareatovolumeratiohavetheadvantage
of low thermal energy losses, but conversely, have less daylight and natural
ventilation potential. To reach net-zero energy, the concept design phase
shouldbedevelopedinaniterativeproceduretogetthemostrationaldesign
satisfying the points raised earlier. For example, if the window-to-wall ratio
is very low, it is difficult to achieve significant daylighting or natural
ventilation, and if this detail is not considered early on, it will be translated