A dynamic state-space model for predicting the thermal performance of ventilated electric heating mortar blocks integrated with phase change material

Thermal active building system (TABS) is promising to increase the flexibility of building energy systems. In this research, the thermal characteristics of a ventilated mortar block in the operation mode that the air is directly exhausted are analyzed by models. The block is integrated with phase change material (PCM) and ventilation tubes to increase both heat storage capacity and heat extraction flexibility. The simplified thermal model of the block, which combines the thermal network model and number of transfer unit model (NTU), is established and rearranged in standard state-space form based on the experimental system. The calculation process is also improved. Different modeling methods are compared, and the accuracy of the model is also validated by the testing data of three kinds of ventilated mortar blocks, which have different layers of PCM inside. Furthermore, parametric analysis is also conducted. The results show that for the current operational mode where the air is directly exhausted, the thickness of the mortar block and the diameter of the tube have a dominant impact on the surface and outlet air temperature, while velocity has a lower impact on the outlet air temperature.