Foundational Design Rules for Solid-Liquid Phase Change Material - Heat Exchanger (PCM-HX)

基于相变材料(PCM)的潜热蓄能系统(LHESS)的使用是一个日益引起研究/商业兴趣的领域；它为能源供应和需求的时间依赖性以及温度管理之间的冲突提供了解决方案。随着当今社会推动更多的可再生/可持续能源生产，这种技术将发挥更大的作用，例如：太阳能家用热水系统，夜间冷藏用于空调和制冷需求的多余能源，建筑物中的相变材料提高整体能效，能源生产系统中的储热，以及用于各种电子设备温度控制的PCM-LHESS。 各种LHESS的核心是流体到PCM热交换器(HX)，用于将能量移入/移出存储系统；由管道或通道、翅片、挡板等组成；类似于用于更传统的流体到流体热交换的HX，不同之处在于现在PCM填充热交换器的一侧。传统的HX在几十年的实验工作基础上，有定义良好和准确的设计规则(-NTU，LMTD，设计手册)来指导设计选择。 然而，PCM-HX没有设计规则。数值模拟仍然不能用于真实复杂的三维LHESS的完整表征，因此新的设计必须通过改变几何、材料和操作参数进行实验测试，这导致了一个漫长而昂贵的过程，不能保证最终将找到经济和实用的设计。这就解释了为什么现在市面上的LHEs很少！ 因此，确定PCM-HX系统的设计规则是PCM蓄热领域所需要的最重要的进步，通过加快LHESS的设计，导致概念验证和技术采用，也将极大地帮助此类系统获得经济上的支持。 我的研究计划的主要目标是回答相关的概念性问题，以比较不同的PCM-HX的特征，并使用比较图来确定用于LHESS的PCM-HX的基本设计规则。 为了实现这一目标，将使用申请人实验室中已建立的台式实验装置来研究和表征五种不同的PCM-HX几何结构。将测量与热传递速率、系统中的温度、流量和压降有关的数据。根据所有的实验结果，将努力确定用于比较每种PCM-HX的性能的正确参数，并由此开发新的规则和理论来辅助针对特定应用的PCM-HX的设计和选择。 设计规则的确定将作为PCM-HX系统领域的基础，从而实现更快、更经济的设计和应用。这将对行业产生变革性的影响。

The use of phase change materials (PCMs) based Latent Heat Energy Storage Systems (LHESS) is an area of increased research/commercial interests; offering solutions to the problem of conflicting time-dependency of the availability and demand of energy as well as temperature management. Such a technology will play a bigger role with today's push for increased renewable/sustainable energy production in our society's energy mix, for example: solar domestic hot water systems, cold storage from night time excess energy for air conditioning and refrigeration needs, PCMs in buildings enhancing overall energy efficiency, thermal storage in energy production systems, and PCM-LHESS used for temperature control of various electronic devices. At the heart of a large variety of LHESS is a fluid-to-PCM heat exchanger (HX) to move the energy in/out of the storage system; composed of pipes, or channels, fins, baffles, etc.; similar to HX used for more traditional fluid-to-fluid heat exchange with the exception that now, PCM fills one side of the heat exchanger. Traditional HX have well defined and accurate design rules (-NTU, LMTD, design handbooks) based on decades of experimental work to guide in design selection. However, no design rules exist for PCM-HX. Numerical modeling still cannot be used for the complete characterization of a real complex 3D LHESS, so new design must be tested experimentally, by varying geometrical, material and operational parameters, resulting in a long and costly process, with no guarantee that an economical and functional design will ultimately be found. This explains why very few LHESS are commercially available today! Therefore, the determination of design rules for PCM-HX systems is the single most important advancement required in the field of thermal storage with PCMs, and through enabling faster designs of LHESS, leading to proof of concepts and technological adoptions, will also greatly help the economic case to be made for such systems. The main goal of my research program is to answer the relevant conceptual questions required to comparatively characterize different PCM-HX and use the comparative figures to determine foundational design rules for PCM-HX used for LHESS. To achieve this goal, five different PCM-HX geometries will be studied and characterized using a benchtop experimental setup already built in the applicant's lab. Data related to the heat transfer rates, temperatures in the system, flow rates and pressure drops will be measured. With all the experimental results, work will be done on determining the right parameters to be used to compare the performance of each PCM-HX, and from this, develop novel rules and theory to assist in the design and selection of PCM-HX for given applications. The determination of design rules will serve as a foundation for the area of PCM-HX systems, enabling faster and more economical designs and applications. This will have a transformational impact in the industry.