Heat Transfer and Phase Change Materials for Thermal Energy Storage and Thermal Management Applications

在面临日益增长的能源需求和气候变化挑战的世界上，储存来自可持续能源（例如太阳能）的热能或回收工业过程中的废热具有重要意义。此外，有效的热管理对于提高许多能源系统的效率和可靠性至关重要，例如蒸汽和燃气轮机、核反应堆以及海上油气生产系统中的海底管道。由于具有较高的熔合潜热，相变材料（PCM）可以在熔化（或凝固）过程中吸收（或释放）大量的热能，同时保持近乎恒定的温度。这些特点使pcm在热能储存和热管理系统中具有吸引力。然而，由于低导热系数和过冷问题，PCMs的实际应用受到了限制。****本研究计划旨在用多尺度方法解决这些挑战。建议将具有高导热系数的纳米颗粒添加到碱性PCM中以增加其整体导热系数。纳米颗粒也可以作为成核剂，可以减少或消除过冷问题。纳米增强型PCMs （NPCMs）将与宏观结构相结合，以进一步增强传热。将开发一个具有这种多尺度增强功能的实验装置，用于太阳能热能储存，以及海底管道的新隔热技术。为了更好地了解npcm的凝固和熔化过程，并实现各种储热和热管理系统的优化设计，将进行数学建模和实验研究。****本研究项目的实验数据和预测工具将为开发效率更高、成本更低的潜热储能和热管理系统提供有价值的见解。来自可再生能源的热能储存将在预计500亿美元的能源储存市场中占据重要份额，并为全球节能和环境保护做出巨大贡献。此外，本研究提出的新型保温技术可能会显著提高海底油气生产线的安全运行，并有助于加拿大和全球海上能源行业的持续增长

Storage of thermal energy from sustainable energy sources (e.g., solar) or recovery of waste heat in industrial processes has great importance in a world facing challenges of growing energy demand and climate change. Also, effective thermal management is critical for the improvement of efficiency and reliability of many energy systems, such as steam and gas turbines, nuclear reactors, and subsea pipelines in offshore oil and gas production systems. With a high latent heat of fusion, a phase change material (PCM) can absorb (or release) significant amounts of thermal energy during melting (or solidification) processes while it maintains a nearly constant temperature. These features make PCMs attractive in thermal energy storage and thermal management systems. However, the practical applications of PCMs have been limited due to the low thermal conductivity and subcooling problems.****This research program aims to address these challenges with a multi-scale approach. Nanoparticles with a high thermal conductivity are proposed to be added into a base PCM to increase its overall thermal conductivity. The nanoparticles may also serve as nucleating agents that could reduce or eliminate the subcooling problem. The nano-enhanced PCMs (NPCMs) will be integrated with macroscale structures for further heat transfer enhancement. An experimental unit with this multi-scale enhancement will be developed for solar thermal energy storage, as well as new thermal insulation techniques for subsea pipelines. Both mathematical modelling and experimental investigations will be conducted to better understand the solidification and melting processes of the NPCMs, and to achieve optimal design of various thermal energy storage and thermal management systems.****The experimental data and predictive tools from this research program will provide valuable insight into the development of latent heat thermal energy storage and thermal management systems with higher efficiency and reduced cost. Storage of thermal energy from renewable sources will gain significant share in a projected $50 billion energy storage market, and greatly contribute to the global effort of energy conservation and environmental protection. Also, the new thermal insulation technique proposed in this research may significantly improve safety operations of subsea oil and gas production lines and help the continuous growth of the offshore energy industry in Canada and worldwide.**