Transient Solution Methods for Dynamic Thermal Modelling within CFD

This paper reports the results of a study to test two novel procedures to model dynamic thermal conditions of an enclosure within Computational Fluid Dynamics (CFD). The main area of investigation is the performance of the procedures in simulating the varying thermal response of the building fabric, the effects of external thermal load changes and the consequential effect on the air inside the enclosure. The dynamic thermal modelling procedures proposed utilise a transient time-varying grid schedule and Freeze-Flow techniques. Freeze Flow pauses the solution of all governing equations of fluid flow, except temperature. The proposed procedures provide the potential for solving the problem of generating large quantities of data, whilst effectively modelling heat transfer through the building fabric and internal air simultaneously using CFD alone. The study has established that both procedures provide accurate simulations (when compared with a fully transient CFD simulation) and identified which of the two procedures is the most efficient and suitable for dynamic thermal modelling within CFD.