Modeling Building Energy Systems: Flows and Heat Exchange

This lecture covers the modeling of energy systems in buildings, focusing on the dynamics of air flows and heat exchange processes. It begins with an overview of the building model, emphasizing the importance of understanding heat loss and the need for heating systems to compensate for these losses. The instructor explains the principles of mass and energy balance, detailing how air infiltration affects heating requirements. The lecture introduces constitutive equations for calculating thermodynamic properties, including enthalpy and entropy, and discusses the role of heat exchangers in optimizing energy use. The concept of degrees of freedom in unit models is explored, highlighting the importance of specifying parameters to ensure calculability. The instructor also addresses the sequential and simultaneous approaches to solving flowsheets, emphasizing the need for a systematic methodology in modeling interconnected units. The lecture concludes with practical considerations for implementing heat recovery systems and optimizing energy consumption in building designs.