Numerical and Experimental Study of Solidification Behavior in Thermal Storage Systems

This dissertation investigates thermal energy storage systems for building applications through experimental validation, computational modeling, and geometric optimization of phase change material (PCM) systems. The study addresses limitations in empirical data, HVAC integration, and configuration design for building-integrated storage. A literature review of ice thermal energy storage methods, focusing on resistance networks, quasi-steady techniques, and enthalpy-based formulations, provides the foundation for PCM model development. A shell-and-tube system using PureTemp 8 and ethylene glycol was tested under controlled conditions, and results validated a quasi-steady analytical model with axial discretization as well as CFD simulations using the enthalpy-porosity method. The investigation extended to an air-PCM system employing PureTemp 20 in an inline tube bank downstream of a mini-split air conditioner, with CFD models incorporating SST k–ω turbulence modeling and validated against experimental and analytical benchmarks. Parametric analysis evaluated the influence of airflow rate and inlet temperature on solidification progression, heat transfer, energy storage capacity, and system performance. Geometric optimization compared rectangular and cylindrical encapsulations under constant PCM volume, using Fourier number and thermal-aerodynamic indices to assess design trade-offs. The results provide validated modeling approaches and experimental benchmarks for PCM systems under HVAC-relevant conditions, along with a framework for selecting and optimizing geometries based on application-specific requirements.