The development of a bench-scale fluidized bed reactor for thermochemical energy storage under partial vacuum

加拿大住宅空间供暖和热水需求的很大一部分可以通过太阳能满足；然而，太阳能热能技术在加拿大的普及目前受到太阳能采暖季节太阳辐射低时所需的相当大的蓄热系统的限制。与传统的在液态水中存储显热所需的大型储罐相比，固体吸附材料与气相中的水之间的热化学反应具有更高的储能密度，提供了更紧凑和无损失的储热解决方案。通过吸附进行的热化学储存是间接的，在吸附过程中，当水蒸气与吸附剂表面结合时，释放出热能。使饱和材料受到与吸附过程中释放的热量相同的热量将打破这些键(解吸)，使材料再生以经历进一步的吸附-解吸循环。在常压下用固定床反应器对包括合成沸石在内的吸附剂进行了研究，结果表明，这些材料具有较高的储能密度和较长的寿命周期。这项研究计划将遵循NSERC成功参与期间为未来工作提出的建议，并将探索压力和流态化对13X沸石吸附的影响，以应用于低温热能储存。预计在较低的反应器温度下，在反应器中的部分真空下可以实现更快的脱附，并且反应器中压力的逐渐降低将延长吸附过程中的热释放。作为固定床设计的延伸，流态化有望改善气固两相之间的传热传质。在用多物理软件模拟了小型沸腾床反应器的综合模型后，将建立一个实验阶段的装置，分别在正压和负压下观察13X沸石的吸附和脱附过程。

A significant portion of Canadian residential space heating and hot water needs can be met with solar thermal energy; however, the penetration of solar thermal technology in Canada is currently limited by the sizable thermal storage systems that are required during the heating season when solar insolation is low. In comparison to the conventionally large tanks required for storing sensible heat in liquid water, thermochemical reactions between solid adsorbent materials and water in the gas phase possess much higher energy storage densities, providing a more compact and loss-free thermal storage solution. Thermochemical storage via sorption is indirect, where enthalpy is released when water vapour bonds with the surface of an adsorbent during adsorption. Subjecting the saturated material to an equal amount of heat as that released during adsorption will break those bonds (desorption), regenerating the material to undergo further adsorption-desorption cycles. Adsorbents including synthetic zeolites have been investigated using fixed bed reactors at atmospheric pressure and promising results have been obtained with respect to the high energy storage densities and long life cycle of these materials. This research program will follow recommendations made for future work identified during a successful NSERC Engage period, and will explore the effects of pressure and fluidization on the sorption of zeolite 13X for the application of low-temperature thermal energy storage. It is expected that faster desorption at a lower reactor temperature can be achieved under a partial vacuum in the reactor, and that a gradual reduction of pressure in the reactor will prolong the release of heat during adsorption. As an extension of the fixed bed design, it is expected that heat and mass transfer between the gas and solid will be improved with fluidization. After a comprehensive model of a bench-scale fluidized bed reactor has been simulated in a multiphysics software, an apparatus will be constructed for an experimental phase in which the adsorption and desorption of fluidized zeolite 13X will be observed under positive and negative (vacuum) gage pressure respectively.