I just saw what is happening with my simulation. Is was not obvious until I saw the "Zone Component Load Summary Report". It revealed a 39% heat loss through the floor slab in contact with ground. Looks like E+ registers a peak design load through the slab on ground within the summer design day that is a heat loss instead of a heat gain in the space. My opinion is that slab on ground heat loss shall be disregarded for a peak cooling load calculation. The "Zone Component component Load Summary Report" is not a default in E+. It is available as an Openstudio measure and in the IDF editor in the class "Output:Table: Summary Report". The default in the idf file is "AllSummary". It is necessary to change the field to "AllSummaryandSizingPeriod". This scenario explains why I was getting the wrong impression of having "adiabatic walls".

I just saw what is happening with my simulation. Is was not obvious until I saw the "Zone Component Load Summary Report". It revealed a 39% heat loss through the floor slab in contact with ground. Looks like E+ registers a peak design load through the slab on ground within the summer design day that is a heat loss instead of a heat gain in the space. My opinion is that slab on ground heat loss shall be disregarded for a peak cooling load calculation. The "Zone component Load Summary Report" ground, which obviously does not make sense. This report is not a default in E+. Energyplus. It is available as an Openstudio measure and in the IDF editor in the class "Output:Table: Summary Report". The default in the idf file is "AllSummary". It is necessary to change the field to "AllSummaryandSizingPeriod". This scenario That explains why I was getting the wrong impression of having "adiabatic walls".