Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 192

aforementioned risks of complex models is partially avoided. The
primary limitation to this category of tool is the available range of
preconceived designs and building systems. Examples of simplified
tools (and their underlying simulation engine) include: HOT3000
(ESP-r), DAYSIM (RADIANCE), Example File Generator (EnergyPlus),
eQUEST (DOE2.2), COMFEN (RADIANCE and EnergyPlus), and SPOT
(RADIANCE).
The aforementioned categories of tools are mostly well-tested and have
minimal inputs, rapid output of results, and are mostly fast to learn and
deploy. In many cases, these tools have underlying assumptions that are
reasonable and prevent inexperienced building designers from venturing
into unrealistic parameter values. This is very convenient for designers and
other tool users who may not have detailed information at the beginning of
design.Theseadvantagescomeatthecostofreducedflexibility(e.g.,limited
number of technologies, design features, and geometries).
Only when the design advances to a detailed level should a model of higher
resolution be used. Two proven strategies for incorporating escalating
model resolution into the design process are the following:
1. Use of multiple models or interfaces of increasing complexity for a
single simulation engine is one promising approach for escalating
model resolution through the design process. Certain tools have
multiple component models with different levels of detail. For instance,
EnergyPlus has three photovoltaic models of increasing detail: simple,
equivalent one-diode, and Sandia (Department of Energy, 2013b). A
simulationist could conceivably start a building model with the simplest
PV model, thus providing faster results with reasonable accuracy and
then progress to more complex models as data become available (e.g.,
exact product specifications) and the demand for accuracy increases
(e.g., when the energy balance is being performed). Similarly, other
building features, such as daylighting, HVAC, and envelopes, lend
themselves well to escalating model resolution.
Another way that a single tool can facilitate evolving model complexity
is to use one of the simulation front ends (the last category of simplified
tools, presented earlier) to build an initial model as a take-off point and
then proceed using the simulation engine directly to add details. For
example, numerous front ends for EnergyPlus (e.g., Example File
Generator (DOE EERE, 2013b)) enable simulationists to create a simple