Context-based thermodynamic modeling of buildings spaces

• Events can render current thermodynamic models less effective for prediction.
• Environments are modeled using several models, instead of a single RC model.
• We describe time-variant environments with a set of RC thermodynamic models.
• A connection is established between thermodynamic modeling and hybrid systems.
• A connection is established between context and thermodynamic modeling.

Thermodynamic models are frequently used for modeling the thermal behavior of building spaces. However, the occurrence of events such as, for example, doors, windows and blinds being opened or closed, can drastically affect the underlying processes that govern the dynamics of temperature evolution of building spaces, rendering current thermodynamic models less effective for control and prediction. This article presents a framework for appropriate model structure and parameter selection that accounts for such discrete disturbances based on the notion of context. Contexts are modeled as discrete configurations, capable of representing different thermodynamic behavior models for a building space. Depending on how context changes, our thermodynamic model transitions through a set of different linear time-invariant sub-models. Each sub-model is effective in representing the thermal behavior of the space under a given context and the result is a hybrid automaton that effectively adjusts to the discrete and continuous dynamics of the building environment. We present an application example and use the outputs of EnergyPlus as reference for model performance evaluation. We show, through different context changes, how a context-based model can be used to represent, with reasonable accuracy, the evolution of temperatures in a simulated thermal zone.