Modeling phase change materials embedded in building enclosure: A review

Thermal energy storage (TES) has the capability to absorb, store and release heat based on dynamic surrounding environmental conditions. Sensible energy storage captures or releases heat with changes in material's temperature while latent heat is associated with a phase change at an isotherm or near isothermal temperature. Latent heat storage such as using a phase change material (PCM) gains growing attentions recently due to its ability of storing significant thermal energy within a small volume, making it one of most promising technologies for developing energy efficient buildings. To quantify their technical and economic feasibility for building's applications, computational models of TES that can be integrated into whole building energy simulations are highly demanded. This paper reviews the different modeling methods generally used for PCM simulations. A few numerical modeling methods are observed in literature for modeling PCMs including the enthalpy method, the heat capacity method, the temperature transforming model, and the heat source method. The study compares and highlights the advantages, disadvantages and limitations of these models and methods. It particularly explores the viability of these methods for building applications. The paper further reviews the PCM models that have been integrated into prevalent whole building simulation programs such as EnergyPlus, TRNSYS, ESP-r etc. The study reveals that the heat capacity method is mostly used in programs, despite of its limitations on time and spatial resolutions. Further research is found necessary to identify the efficiency and accuracy of these methods in building applications.