I am having same problem as below....Did anyone ever receive a helpful answer to this thread?
For example, I made a 10ftx 10 ft x10 ft cube with the same very low U value on each of the six surfaces. I did a thermal analysis for various window areas on the south wall. My understanding of basic passive solar design is that expect that should get passive gains during day and losses at night from night, at some optimum window area (e.g. 10% of window area) would get a decrease in heating load from passive gain.
However Ecotect showed that the heating load constantly increased as window area increased in small increments from 1ft x 1ft to 9ft x 9ft. Tried various window types, usually low e double pane and various parameters for window and walls to optimize absorptionand transmission surface normals are outward but got same results
If it cannot model this simple situation how reliable the thermal model is for passive design?