Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 166

Fig. 4.3 Natural ventilation in an atrium (BC-EPFL Lausanne Switzerland,
Architect: R. Luscher Lausanne, Energy Concept: Sorane S.A, Ecublens)
Similar to the case of thermal inertia, evaluating the effectiveness of natural
ventilation requires coupling the thermal and the airflow networks. Such
coupling is provided in advanced building simulation tools (e.g., TRNSYS
and TRNFLOW (University of Wisconsin, 2012), EnergyPlus (DOE, 2012)).
During theconcept design phase, however, theimplementation ofa detailed
model is difficult because it would be very time consuming and it would
require many assumptions, such as details ofthe building envelope, internal
gains, fenestration, and shading devices. At this stage of the design, simple
tools like COMIS are better adapted for early-stage natural ventilation
modeling. These simple tools can evaluate the air exchange rate and the
effectiveness of the natural ventilation with a limited number of inputs
like the wind pressure coefficients, the height of the openings and their
discharge coefficient (a characteristic of openings that takes both the