A Look at LBNL's COMFEN Software

Sophisticated building modeling software provides the design community with tools to simulate performance of each elevation of a building based on location, date and time, and product type. COMFEN, from the Lawrence Berkeley National Laboratory, is a leading tool for the building industry in modeling overall energy performance, heat gain, daylighting and thermal comfort.

(All images supplied by LBNL)

COMFEN Chicago
This sample COMFEN model of a building in Chicago shows the solar heat gain coefficient and visible light transmittance on each face of the structure, with double-clear low-emissivity glass used throughout. For each face of the building, COMFEN can model annual energy use (bar graph in the middle left), and monthly average window heat gain (bar graph in the middle right). The program can also model daylighting for any given date and time, for each elevation of the building (modeled is the daylighting projection for 12 p.m. on June 21). COMFEN also offers thermal comfort information for each elevation, throughout the day (in the lower right).
COMFEN Phoenix
For comparison, pictured is the model of a sample building in Phoenix, with the same glass type (double-clear low-E). 
COMFEN Chicago, Energy Use
COMFEN allows users to compare a side-by-side energy use comparison of different glass types. Pictured is a sample analysis of two types of glazing systems in Chicago, with energy use calculated for each orientation. The above chart shows, for example, that spectrally selective low-emissivity glass products will have a larger impact on the west, east and south elevations, but minimal impact on the north elevation.
COMFEN Chicago, Heat Gain
COMFEN offers comprehensive heat gain simulations for each elevation of a building, at any time of day throughout the year. Pictured is the heat gain analysis for a building in Chicago, which shows the growing intensity of heat on the west façade during the afternoon hours (heightened during the summer months), on the east façade during the morning hours (also heightened during the summer months), and throughout the day on the south façade. The north façade, with no direct sunlight, experiences very little heat gain throughout the day, year round. 
COMFEN Chicago, Heat Gain (with and without shading)
Pictured is a heat-gain map of just the west façade, with and without shading. The simulations on the left show two types of insulating glass units without shading; the simulations on the right show two glass units with interior and exterior blinds. The exterior blinds provide the largest impact on heat-gain for the west façade.
COMFEN Chicago, Daylighting (with and without shading)
COMFEN’s daylighting analysis allows users to perform side-by-side comparisons of several glass types for any orientation, on given day, for any given location. Pictured is the west face of a building in Chicago on June 21. The far right column shows a double-clear low-E insulating glass unit with interior blinds, in comparison with two other types of IGUs without shading.