Optimised Solar Thermal Storage System for Delivering Process Heat at Temperatures Above 160 C

本研究的核心目标是开发一种新型的利用相变材料(PCM)的太阳能蓄热系统。相变材料是一类吸收或释放能量时发生相变的材料。它们通常在吸收热量时进入液体状态，并在吸收热量时固化。相变材料具有很高的储能潜力，这是因为相变材料的潜热容量是指材料发生相变时所吸收或释放的能量。该系统旨在利用聚光太阳能集热技术的发展，该技术提供高温，并将其与PCM储热相结合。本研究旨在利用潜热储存能力，储存相对较大的太阳能热能，并在需求点释放能量。这项研究将特别关注提供适用于中温范围工业过程的温度和加热曲线。详细的科学目标开发相变材料，提高所需的性能，如导热系数和熔化温度。这项活动将使用计算机模拟进行，然后进行实验验证。确定影响相变材料热循环稳定性和长期(季节性)储存能力的因素，并采取措施减轻热循环和长期储存的负面影响。热循环稳定性的定义是材料在保持其热性能的同时可以经历加热和冷却循环的次数。初步调查将通过标准材料特性测试进行，然后使用扫描电子显微镜(SEM)进行显微镜检查。将确定退化因素，然后应用纠正措施，并对材料进行重新测试。开发一种模型来解释熔化和凝固过程中的相变边界运动，并利用从熔化和凝固模型中获得的知识来优化换热器设计。新颖的模型来理解、量化和可视化相变材料的熔化和凝固过程。相变材料经过优化以经历更多的热循环，用于长期能量存储时降解较少。开发一种新型的换热器，以利用相变材料的熔融和凝固轮廓。在工业规模上，用于储热和输送的系统设计，使用优化的PCM作为存储介质。对社会有益英国的工业过程占全国能源使用量的近16%，其中一半以上的能源来自不可再生能源，这项研究希望通过改进存储技术和提高温度的能力，使太阳能成为工业环境中可行的替代能源。拟议工作的潜在应用包括食品加工业、茶叶工业和聚合物制造中的工艺。

The core aim of the study is the development of a novel solar thermal energy storage system using phase change materials (PCM). PCM are a class of material which change phase when absorbing or releasing energy. They typically enter a liquid form when absorbing heat and solidify when the heat is extracted. PCMs have high thermal energy storage potentials due to the material property of latent heat capacity, the amount of energy absorbed or released when a material undergoes a phase change. The system aims to take advantage of the developments in concentrating solar thermal collector technology which deliver high temperatures and couple it with PCM heat storage. This study aims to use latent heat storage capability to store a relatively large amount of solar thermal energy and release the energy at the point of demand. The research will give specific attention to delivering temperatures and heating profiles suitable for mid-temperature range industrial processes.Detailed scientific objectivesDevelopment of PCM which enhances desirable properties such as thermal conductivity and melting temperatures. This activity will be carried out using computer simulation followed by experimental verification.Identify the factors affecting the thermal cycle stability and long-term (seasonal) storage capability of PCM and incorporate measures to mitigate the negative effects of thermal cycling and long-term storage. Thermal cycling stability is defined as the number of times a material can undergo heating and cooling cycles while maintaining its thermal properties. Initial investigation will be carried out through standard material characterisation tests followed by microscopy using scanning electron microscope (SEM). Degradation factors will be identified, followed by the application of corrective measures and the material will be re-tested. Development of a model to explain the phase change boundary movement during melting and solidifying and development of heat exchanger design with optimisations led by knowledge gained from the melting and solidifying model.NoveltyModel to understand, quantify and visualise the melting and solidifying process of PCM.PCM optimised to undergo more thermal cycles and degrade less when used for long-term energy storage.Development of a novel heat exchanger designed to take advantage of the melting and solidifying profile of PCM.An industrial scale, system design for storage and delivery of heat, using an optimised PCM as the storage medium.Benefit to societyWith industrial processes accounting for nearly 16% of national energy usage in the United Kingdom and over half of that energy coming from non-renewable sources, it is the hope of this study, to make solar thermal energy a viable alternative in an industrial setting, through improvements in storage technology and capability to deliver higher temperatures. The potential applications of the proposed work include processes in the food processing industry, tea industry and polymer manufacture.