Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 151

approaches to modeling different Net ZEB features and systems, and
suggestions on how to use BPS tools to influence design and visualize the
design space.
While the two sections each approach the Net ZEB design problem from
a different perspective - practice and research - they yield very similar
conclusions. One of the main conclusions is that the design of Net ZEBs
requiresthatenergy-relateddesignconsiderationsoccursignificantlyearlier
in the design process than for conventional buildings. Also, the most
permanent design decisions should be made early in the design process.
Many of these specifications - building form, thermal mass strategies,
opening area, envelope design, structural systems, and potential for
integration of renewable energy systems - greatly affect energy use. Finally,
one of the key needs in simulation tools development is to enable escalating
model resolution in simplified tools as the design progresses. Certain
phenomena should be assessed early in design because they could be very
influential over building form and other major decisions, but require
detailed analysis, namely, natural ventilation, daylighting, and control
strategies are nontrivial aspects. This chapter provides theory and examples
for possible simplified methods.
4.2 Integrating Modeling Tools in the Net ZEB Design
Process
4.2.1 Introduction
The design process of conventional buildings without specific objectives
related to energy or environmental aspects is generally linear. The building
owner establishes his priorities and requirements; the architect is
responsible for building siting, orientation, form, and building envelope;
the structural and electrical engineers are responsible for their respective
systems; and the mechanical engineer selects and sizes the appropriate
HVAC system. The issue with this type of design process is that major
irreversible decisions about the building design, such as form and
orientation, are sometimes made with little regard for energy performance.
When the design target is to build a Net ZEB, energy consumption,
environmental impact, and comfort are major concerns. Relevant decisions
have to be made carefully during early design stages because they have an
enormous impact on building energy consumption and potential for RET