Low thermal conductivity is a significant issue for the deployment of phase change based thermal energy stores. A structured methodology is required to find the best overall design, in order to assess its techno-economic feasibility. In this study the optimised structural configuration of graphite composites for this purpose are first considered from three different perspectives using both experimental measurements and numerical simulations. Both steady state and dynamic performance are taken into account, with the latter being considered both with and without phase change. In all three cases it is demonstrated that thin, parallel graphite sheets offer the most optimal results compared to other options. Resulting in the highest composite thermal conductivity measured to date at a loading of 3.5 mass%. The next step in achieving the best overall performance is the optimisation of this composite in the context of a plate and frame heat exchanger. For this purpose a simplified analytical model of this configuration was developed and validated. This was used in conjunction with the log mean temperature difference approach to optimise the exchanger for two typical applications: low temperature, low duty and high temperature, high duty. The results indicate that, even under an idealised configuration, the system will only be suitable for high temperature applications with gas heat transfer fluids and short discharge times (~1 h). For low temperature applications it may be possible to use liquid heat transfer fluids but also only for short discharge times. From an economic perspective, the range of graphite sheets currently available on the market will have to be reduced in cost by two or more orders of magnitude in order to be cost-effective.

对于基于相变的热能存储器的部署，低导热率是一个重要的问题。需要一种结构化的方法来找到最佳的总体设计，以便评估其技术经济可行性。在这项研究中，首先使用实验测量和数值模拟从三个不同的角度来考虑为此目的而优化的石墨复合材料的结构构造。同时考虑了稳态和动态性能，考虑了有或没有相位变化的情况。在所有三种情况下，与其他选择相比，平行的石墨薄板可提供最佳的结果。迄今为止，在3.5质量％的负载下测得的最高复合导热系数。要获得最佳的总体性能，下一步就是在板框式换热器中优化这种复合材料。为此，开发并验证了此配置的简化分析模型。它与对数平均温差方法结合使用，以针对两种典型应用优化交换器：低温，低负荷和高温，高负荷。结果表明，即使在理想配置下，该系统也仅适用于气体传热流体且排放时间短（约1小时）的高温应用。对于低温应用，可以使用液体传热流体，但也只能用于较短的排放时间。从经济角度来看，