Question-and-Answer Resource for the Building Energy Modeling Community
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If you are using the WindowMaterial:GlazingGroup:Thermochromic object for switching between light and dark tints in one window surface, then according to this section of the Input Output Reference discussing the output variables available ...
The overall properties (U-factor/SHGC/VT) of the thermochromic windows at different specification temperatures are reported in the EIO file. These window constructions are created by EnergyPlus during run time. They have similar names with suffix “_TC_XX” where XX represents a specification temperature.
There is an example file called ThermochromicWindow.idf that uses this object. If you run a simulation and examine the EIO output file, then you will find a line that specifies SHGC for each reference temperature defined by the Optical Data Temperature input field.
This data in the EIO file is only calculated once while processing model inputs, not every timestep. You could manually calculate SHGC at each timestep using the window surface output variables Surface Window Transmitted Solar Radiation Rate and general surface output variable Surface Outside Face Incident Solar Radiation Rate per Area (multiplied manually by the window surface area).
