Net ZEB Case Studies - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 429

of decision-making in the design process makes it more time and cost
prohibitive to implement any significant change to the set direction of the
project. (See Chapter 4 for more detailed discussion).
These design changes can come from any one of the building stakeholders.
They can come from the designers due to incomplete or erroneous
information or coordination; the building owner due to scope, program,
budgeting, or timeline changes; the contractors due to design/
constructabilityerrors,constructionerrors,orothersite-specificconditions.
In this respect, the early design stage is crucial for ensuring that the most
important elements for any building design project are accounted for.
Therefore, right from the early design stage of a project, construction costs
and operations and maintenance costs must be considered (Paulson, 1976).
Otherwise, making major changes late in the design process usually causes
downstream consequences, such as redesign, recoordination with all
affected professional disciplines, and rebuilding of energy models, among
other things. From a construction perspective, such late design changes
may also have important effects on coordination of trades and sequencing
of the work, thereby increasing construction costs and causing delays.
Furthermore, such changes during construction can produce effects that
extend even further to the normal operations and maintenance, and
expected usage of the completed building.
Some important design parameters in solar Net ZEBs that must be
addressed at the early design stage have already been discussed but are
summarized here with comments on their impacts on the global project of
the RSF.
1. Building siting, orientation, and geometry (including roof pitch and
area). Building siting and orientation are the first steps in determining
solar accessibility on any particular building site. From there, building
geometry further defines the quantity of solar energy that can be
captured in a project.
The RSF is sited on a predominantly east-west axis to maximize
building insolation. The wings are spaced far enough apart to avoid
self-shading and the roof slope is 10 ° to facilitate installation with a
standing seam metal roof while making it easy to maintain or replace
components of the PV system.