| The development of thermal storage technology can effectively solve the problem of energy discontinuous in time and space, and enhance the efficiency of energy utilization. The investigation of thermal energy storage materials at present is mainly on the sensible heat storage material and the latent heat storage material(PCM). Both of them have some deficiencies in the using process. The weakness of former is the small heat storage density and difficulty in control for the reason of large temperature range of heat storage and release. The latter may produce liquid in the processing of phase change which needs container; however, the liquid is very corrosive at high temperature which put forward higher requirements on the vessel. In order to make full use of the advantages of both materials, inorganic salt-ceramic composite material is proposed.The mixed sintering process was adopt to composite the phase change materials KF-KCl and SiO2 composite ceramic materials, and the polyvinyl alcohol was addition as the adhesive, B2O3 as sintering aids, the ceramic matrix composite heat storage material was successfully developed. The XRD analysis showed that: there was good chemical compatibility between the various substances composite heat storage material composed of KF-KCl/SiO2. The TG-DSC analysis indicates that: the composite material has a heat absorption peak at 591.7?, the latent heat of phase transformation was 157.4J/g. The composite material has the characteristics of high thermal storage density and no need of container which can achieve a high temperature thermal storage.In the paper, the influence of raw material ratio, forming pressure, sintering temperature, holding time and sintering additive content on the sintering quality of composite heat storage material were studied through a large number of tests, and the best ratio of the content of inorganic salt was determined as 40%, the molding pressure was 20 MPa, the holding time was 5min, the sintering temperature was 750?, the holding time was about 120 min, the content of sintering aids was 5%.In order to meet the requirements of composite heat storage material retention capability of heat storage in the long-term using the process, the thermal cycling test of 100 times were proposed on the KF-KCl/SiO2 composite heat storage material, and every 10 times the tests of the quality, the phase transition temperature and phase change enthalpy. The weight loss increases with the increasing of test times, after 70 times the rate of weight loss slow down, and after 100 times the composite weight loss rate was about 3.32%, the latent heat value decreased by 3.24%, the phase transition temperature keeps constant and the compressive strength was 25 MPa. The results indicates that the KF-KCl/SiO2 composite heat storage material with good thermal cycling stability and thermal shock stability. |
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