Addendum to: "Zone aggregation errors in grey-box models of commercial building air-conditioning energy consumption"

This addendum accompanies a study investigating the modelling errors introduced when representing a multi-zone building as a single equivalent thermal zone in grey-box building energy models. Grey-box models combine simplified physical representations with data-driven parameter estimation and are widely used when measurement data are limited. Although real buildings consist of multiple thermal zones, single-zone models are often used to reduce model complexity and parameter estimation challenges.The study considers buildings served by fan coil units with a dedicated outdoor air system (FCU + DOAS). Reference data were generated using forward multi-zone simulations, which allowed controlled variation of inter-zone heterogeneity in parameters such as thermal properties, temperature setpoints, and occupancy-related latent loads. These simulation datasets were then used to evaluate the impact of zone aggregation on parameter estimation and on the accuracy of predicted sensible and latent cooling loads.This addendum provides additional details on (i) the numerical implementation of the models, (ii) the specification of the forward simulations, and (iii) the estimated parameters (results from the inverse problem).