Numerical and experimental investigation on dynamic thermal performance of floor heating system with phase change material for thermal storage

The floor heating system with phase change materials (PCMs) for thermal storage is an effective approach to increase the floor thermal capacity and reduce indoor temperature fluctuation range. A two-dimensional numerical model of the floor heating system combined with PCM was developed to investigate its dynamic thermal performance in winter. To verify the reliability of the model, an experimental room was established in Beijing, China. The experiment results agreed well with the modelling results, which demonstrated that the numerical model was reliable. The effects of the phase change temperature, latent heat and thermal conductivity of PCM on the thermal performance of the floor were numerically investigated. The results showed that the phase change temperature and thermal conductivity of PCM had a significant influence on thermal comfort. At the same time, these two thermal physical parameters also played a critical role in improving the utilization rate of PCM. Conversely, the latent heat, in the range of 100 to 200 kJ/kg, had no obvious influence on the thermal performance of the floor. PCM with phase change temperature of 313 K was recommended, which could increase the average indoor temperature by 2.2 K, increase the thermal energy storage ratio by 12% and reduce indoor temperature fluctuation range by 2.2 K.