화학공학소재연구정보센터
International Journal of Energy Research, Vol.45, No.4, 5177-5189, 2021
MgSO4 composites in a ferroaluminophosphate for enhancement of volumetric heat storage capacity at a low charging temperature
Ferroaluminophosphate (FAPO(4)-5)/MgSO4 composites were prepared as a series of new materials with low charging temperatures and improved volumetric heat storage capacities. A microporous zeolithic compound FAPO(4)-5 was used as an adsorbent of water vapor and a matrix of MgSO4 salt particles. Composites with various MgSO4 contents (5-40 wt%) were then prepared using a wet impregnation method. The MgSO4 salt particles were impregnated into the micropores and textural pores of FAPO(4)-5 without the crystal structure of the host material, confirmed by XRD patterns. Although nitrogen adsorption isotherms of the composites showed approximately a half of FAPO(4)-5 pore was blocked by MgSO4, the water uptake of the composites reached the sum of those from FAPO(4)-5 and MgSO4. The dehydration temperature of MgSO4 in the FAPO(4)-5 matrix decreased with its decreasing content due to the easier dehydration of FAPO(4)-5. The heat storage recovery of the 25 wt% loaded sample at 80 degrees C was 85.5% while that of MgSO4 was 52.2%. The swelling and agglomeration of the composites containing 25 wt% and less salt were suppressed by the micro and textural pores of FAPO(4)-5. The composite at 25 wt% of MgSO4 loading exhibited a total volumetric heat storage capacity of 174 kW h m(-3) based on the volume in the hydrated state.