Development of Reduced Order Thermal Models of Building Integrated Active PCM-TES (OR-16-021)

This paper presents an experimental and numerical study focusing on the development of control-oriented thermal models of varying resolution for an actively charged/discharged phase change material thermal energy storage (PCM TES) system intended for building integration. This PCM TES system consists of five layers of PCM panels with an air channel between the middle layers. Conditioned air is drawn through the cavity to charge and discharge the PCM. The PCM TES system is tested in an environmental chamber where its dynamic response was carefully monitored. The monitored data is used for model development and validation. Compared to a detailed 30th order RC model, simplified 4th order and 2nd order models are shown to be able to satisfactorily predict the thermal energy storage and release of the PCM TES system. To simplify the PCM characterization input and to reduce the simulation time, a five-parameter equation is developed to model the PCM specific heat and a four-parameter equation for its thermal conductivity. The presented modeling methodology is applicable for similar PCM TES systems with multiple PCM layers and air flow channels.