变压力条件下带相变储热备用的先进钙基热化学储热瞬态行为与热力学分析

Abstract A cascaded thermal energy storage system integrating calcium-based thermochemical energy storage (TCES) with latent heat storage (LHS) backup unit was developed, targeting medium-to-high-temperature applications and enhanced system performance under Brayton-like Carnot battery operation. In this paper, a high-pressure fixed-bed TCES reactor employing Ca(OH) 2 /CaO was developed and experimentally tested to assess thermal performance, kinetic behavior under varying steam temperatures and pressures and cycling stability. Besides, a comprehensive one-dimensional transient numerical model was established to simulate the coupled heat transfer behavior of the cascaded TCES and LHS unit, and to assess thermodynamic metrics including round-trip efficiency, energy density, and exergy utilization. It turns out that the TCES material maintains a relatively high conversion rate of 76.9 % after undergoing ten consecutive hydration and dehydration cycles at the reactor scale, with the decomposition temperature set at 550 °C and the operating pressure at 2 MPa. Besides, the results indicate that the integrated TCES-LHS system achieves a volumetric energy density of 342.8 kWh/m 3 at a porosity of 0.4. The integrated system could also achieve a round-trip efficiency of up to 52.7 % and enhanced exergy efficiency of 61.6 %. This work advances the practical deployment of calcium-based TCES with LHS backup in a high-efficiency Carnot battery or concentrated solar power system.