Performance comparison of high-temperature packed bed operation with PCM and sensible-heat pellets

A comparison is made between two specific thermal energy storage materials, zirconium oxide (ZrO2) as a sensible‐heat material and a salt/ceramic composite (Na2SO4/SiO2) as a phase change material, for high‐temperature applications. Second‐law thermodynamic analyses along with material stability tests are employed as criteria for the assessment of these materials. To facilitate the analysis, case studies are presented, and the thermal behaviour of the packed bed for each scenario is simulated by an experimentally validated computational model. The case studies are designed to examine the role of the heat of fusion and the material quantity in the thermal performance of the packed bed. For stability evaluation, these materials are exposed to a number of thermal cycles in a high temperature test environment. The zirconium oxide pellets not only offer excellent physical stability but prove to be thermodynamically promising as well. © 1997 by John Wiley & Sons, Ltd.