Thermal Characteristics Of Floor Radiant Heating Using Capillary Mat And Phase Change Materials For Energy Storage

Phase change material integrated with capillary mat are applied in low-temperature radiant floor heating. Thermal characteristics of this heating mode have been investigated both experimentally and numerically.First, a low-temperature radiant floor heating system was set up with the capillary mat and the common PE pipe combined with sand and phase change material (PCM), respectively. Experimental investigations were performed on the heating performance and charge/discharge characteristics of these four different combinations. The results showed that, in the daytime, the time to attaining the same room temperature for sand-capillary combination is only40%of that for sand-PE pipe combination and the corresponding time for PCM-capillary mat combination is44%of that of PCM-PE pipe combination. At night, after the auxiliary heat source is closed, the room heating effect was examined for these four combinations for heat storage in floor layer. It was found that phase change material as the heat storage layer releases heat2times longer that using the sand. Further experiments were performed on the PCM-capillary mat combination for different flow rates of hot water and the results showed that the heat storage rate by higher flow rate of1.4m3/h is1.4times larger than the lower flow rate of0.81m3/h. The time period keeping the comfortable room temperature for high flow rate is1.14times longer than that for the low flow rate.Based on the experiment, preliminary simulation was made on the temperature of the floor structure layer by CFD software. The simulation results show reasonable agreement with the measured data in both charge and discharge process. The simulation and experimental results are helpful to the design of solar-hot-water radiant heating system with the combination of the PCM and the capillary mat.