Kia ora @charlie.brooker
I agree with you that the ‘storage’ term is by definition a disparity between the gains and losses determined for each month by the Load Balance component. As noted in the discussion in upir 2020 post:
Understanding the storage amount in the Load Balance graph - @Charlie.brooker
Having tried building this type of report myself in a spreadsheet I know that it is combining output from at least 2 very different EnergyPlus reports. I can see how this accounting of typical flows might not in some circumstances account for all the energy flows in a model. Specifically, I note very big “storage” values can be made to appear when I manipulate the window opening temperature control setpoints. I have very deliberately pointed out to my students that this so-called storage term in the otherwise extremely useful Load Balance graph is an error term which if small could be presumed to be energy stored in the fabric of the building - but that if it is genuinely ‘storage’ then one might expect it to be randomly positive or negative depending on the season. If it is large and systematically gains or losses, then it is more likely an indication that there is something in their model they do not understand. Not wrong, but possibly an indication of behaviour they do not quite understand in the model.
Thanks for the heads up about the air-side economiser I will investigate.