Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 190

provide information on the relative effectiveness of design techniques and
technologies to approach net-zero energy.
The use of simplified tools in early design is further justified by the fact that
(a) there are diminishing returns on model accuracy as model resolution
increases, and so, simple models can still provide significant accuracy (see
Figure 4.10 ), and (b) simple tools are typically easier to understand and
thus, confidence through understanding tends to be higher. However,
transparency of the underlying mathematical model of BPS tools should be
high so that users are aware of their assumptions and limitations. One of
the reasons why designers may avoid simplified tools in favor of detailed
ones is that they feel detailed models are risk-free since all building aspects
are supposedly modeled in an integrated way. However, evidence suggests
that the use of complex tools, beyond a certain point, can decrease model
accuracy (Chwif, Barretto, and Paul, 2000). This is primarily because
complex models have many more inputs (e.g., building details) that may be
obscure to nonexperts who enter or set them inappropriately. Furthermore,
errors in complex models are more difficult to identify and may go
unnoticed.
Fig. 4.10 The conceptual relationship between model integration and
accuracy and computational time
Recommended simplified tools and approaches for early-stage Net ZEB
design are as follows:
- Databases and case studies represent a starting point for exploring
other high-performance buildings of a similar type and climate. These
can identify successful and poor design features. Example Net ZEB
databases include Net-zero energy buildings map of international