Net ZEB Design Processes and Tools - Modeling, Design, and Optimization of Net-Zero Energy Buildings - page 170

In order to assess thermal bridges and condensation, simple tools like
catalogs and handbooks from the American Society of Heating,
Refrigerating and Air-Conditioning Engineers (ASHRAE) can be used
(ASHRAE, 2009). For innovative or one-of-a kind solutions, more complex
tools like 2D and 3D conduction software can be useful, such as THERM
(LBNL, 2012), HEAT 2D, and HEAT 3D (Blomberg, 1996). These tools
can be used first to obtain the internal surface temperature for extreme
conditions and second to evaluate the heat flow across the bridge for a
certain temperature difference. Effective U -values including framing and
thermal bridging can then be calculated. These effective U -values can then
be used in simulation tools like EnergyPlus, TRNSYS, IDA ICE or ESP-r
(ESRU, 2010) to estimate the heating and cooling energy consumption.
4.2.5.2 Daylight
In the design development phase, details regarding window types and sizes
as well as fixed shading devices are finalized. Calculations integrate more
elements than in the concept design phase because information such as
the coefficient of reflection of the internal walls and the window visible
transmittance and frame fraction are now known. At this point, detailed
simulation tools can be more appropriate than simple tools because they
can integrate frame details and shading devices. They can also take into
account interactions between zones, especially between atria and adjacent
zones. Figure 4.4 presents a comparison of the daylighting evaluation in
zones adjacent to an atrium obtained with both detailed and intermediate
simulation tools. This figure shows that while both tools provide similar
results for the first floor, there are significant discrepancies for the second
and third floors. In addition, the atrium mean daylight factor predicted
by the intermediate software is much greater than that predicted by the
detailed software. This shows the importance of revising calculations with
more appropriate tools as the design is refined. A comparison between
the results obtained with a Radiance simulation and a photograph of the
constructed atrium is shown in Figure 4.5 .